The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands) for one week. The question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research. These devices are mainly used for orientation (determining where you are), navigation (determining where to go) and communication (exchanging information with others or accessing information services). But the devices can also be used for tracking, i.e. saving a travelled route into a track log. This ability makes the technology useful to collect spatial-temporal data and thus as ‘sensors’ for observing and measuring activities of people [The availability of so-called geopositioning devices such as GPS  devices has grown enormously in the last decade and is still increasing. More and more people own a f people .GPS is a Global Navigation Satellite System (GNSS). GNSS is a system for location or position determination – so called geopositioning . Using aGNSS is an essential Positioning Determination Technology for many fields of study. Although in recent years the system has undergone a significant ‘modernisation’ to improve its quality , the cap1.2.The most general definition of a sensor is ‘a device which detects or measures a physical property’ (Compact Oxford English Dictionary). A more specific definition of a sensor is ‘a device that responds to a physical stimulus  and transmits a resulting impulse (as for measurement or operating a control)’ (Merrian Webster). Seeing GPS as a sensor requires use of the latter definition. Rather than a physical property it measures the location and motion of a GPS device and the person or object that carries it. The output is in the form of a track log with 3-dimensional spatial location coordinates and a time stamp. In an effort to characterize different types of sensors, Michahelles and Schiele  distinguet al [et al. [et al. [GPS is not the only technology for sensing location and activity of humans. For a few years already, mobile phone technology, RFID and Bluetooth can also provide easy-to-handle sensing data on location and activity. However, these technologies have their particular drawbacks with regards to the type of experiments described below. For more on those technologies see Shoval’s ideas about ‘human sensing’  and tracet al  and Ahas [et al.  using mo [et al.  using Bl [et al.  using RF [et al.  using Wi1.3.With the increasing use of GPS and other tracking technologies, the number of scientific publications on these technologies and their application is also increasing. The aim of this paper is to add a new dimension to the evaluation of tracking studies, namely to evaluate the sensory qualities that GPS technology offers for researching measures of urban quality, where most research focuses on other fields of expertise.Transportation science is a major field of research in which tracking studies have developed and on which tracking research builds . Janelleet al. [Envisage and embody ‘blue sky’ innovations;Explore user experiences and social implications outside commercial implementation;Tackle technical problems that lead to system developments without an early return.Studies focussing on location based services (LBS), a relatively new field of study, form the major part of GPS technology-oriented research. In their opening article to the new Journal of Location Based Services, Raper et al.  set out In general, studies related to LBS strongly attach to the importance of data visualisation (see ), but geFuture studies are another popular field of study in which tracking technologies get attention. For example, Ahas and Ular  go as fa1.4.In general, many studies focus on technical issues regarding GPS, rather than on the application of knowledge derived from a tracking study. If they are knowledge-oriented, studies often focus on a singularly empiricist approach, rather than on application of knowledge. There is a tendency to fill the gap between empirics and application by collecting greater and greater data sets, since ‘the more data the better you know what to do’. Although for some issues, like performing diagnostics on the level of a complete transportation system, this might be so; this argument does not always hold up. Still, handling large data sets is a significant problem that has to be dealt with in all but the smallest studies using GPS, so that automation of data processing will become ever more necessary. In addition, reduction of data complexity through data visualisation might offer complementary alternatives to data mining.However, since the major focus in the body of literature on tracking is on progress of GPS technology, studies in the fields discussed above often lack attention to the particular problems regarding knowledge application in the field of planning . If the et al. developed interesting research techniques based on observation and counting [Although the sudden interest for patterns of use in tracking studies might suggest that research into use aspects of urban quality in urban design is new, there are interesting examples available based on other research techniques and approaches. For example, Gehl counting . Classiccounting  who focuHence, it is interesting to look at the value of GPS as a research technique in the context of urban studies and in particular urban design and planning for two reasons: (1) it might add to the knowledge on the use value of urban spaces, (2) it offers an intriguing new technique which enables research possibilities not available with either traditional urban analysis techniques or low-tech research techniques for studying behaviour patterns in time and space. So the main question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people, in particular in the context of studies regarding urban quality? By looking at two different research projects by TU Delft using GPS, this question is answered along three lines. Firstly, what is the contribution of GPS to traditional methods of urban research? Secondly, what is the performance of GPS as sensor instrument? Thirdly, in what ways can GPS-devices be deployed in urban settings?In this paper we will first describe the general process and database architecture and the particular approaches used in the different case studies. Next, we show how the empirical results in the different research projects provide insight into GPS as a sensor technology with relevance for studies on urban quality.2.2.1.GPS devices have been used by TU Delft to track people in several experiments. The experiments, of which we describe two here, had different research aims and took place on different scales. In the first experiment described in this paper, GPS devices were deployed in the INTERREG IIIB Spatial Metro project to observe pedestrians visiting the historic city centres of Norwich (U.K.), Rouen (France) and Koblenz (Germany) ,31. In tapplicability gap between empirical studies on behaviour and the making of an urban design [applicability gap: (a) the tendency to collect more knowledge on restricted parts of situations, burdening the synthesising capacities of designers, (b) knowledge generated through empirical research not being geared towards the information need of designers – for example empirical researchers tending to communicate verbally, while designers tend to communicate visually, and (c) designers not formulating synthesis-oriented research questions for spatial scientists.The GPS-experiments described in this paper were set up to tackle questions about urban quality in the field of urbanism, i.e. the design and planning of urban areas. However, the application of data from GPS experiments in urbanism is not a matter of course. The expert meeting ‘Urbanism on Track’ in 2007 showed that GPS does not automatically bridge what can be called the n design . Klaasenn design  lists thDespite these limitations, GPS is an interesting new instrument to map and measure urban quality in new ways. The particular cases in this paper refer to different types of urban quality that can be studied using GPS. Spatial Metro is a research program which focuses on urban quality from the perspective of pedestrians. The aim of the program is to find new and exciting ways of improving city centres for pedestrians. GPS was used as an instrument to analyse both individual routes  and col2.2.In general, the GPS experiments developed by TU Delft contain two main parts. Firstly, spatial-temporal data and background information is collected during field work. Secondly, the collected data is retrieved and processed.The field work consists of the following four phases see : (a) preFollowing the field work the data is retrieved from the GPS devices and processed for further analysis. During the processing phase the valid trajectories are converted into three types of ‘shape files’  using GPSU batch utility. These shape files can be linked in ArcGIS using the Data Interoperability Tool (DIT). In ArcGIS the layers containing the trajectories are merged and connected to the Access database using a unique trip ID.The Access database containing the interview data and some characteristics of the trips are converted into SPSS for frequency, cross-table and cluster analysis. In ArcGIS, several actions are undertaken: data is selected (query) based on the combination of SPSS and GIS and analysed using filtering, layering and calculations, such as density analysis. A distinction between two types of density calculations can be made: point density (time corrected) representing the total time spent on a location and line density representing the number of people.In the ‘visualisation & interpretation’ phase the results of the analysis phase are exported to static and dynamic file formats leading to illustrated temporal maps (e.g. .ai or .pdf) and animated temporal maps (e.g. .mov or .swf). Based on interpretation of the results, conclusion maps are drawn. The final versions of these maps are produced in an iterative process by exporting new output from ArcGIS.2.3.For the Spatial Metro project the GPS tracking devices were distributed continuously during daytime over a period of one week at two parking facilities in each of the three cities ,31. ThesA questionnaire was filled out on return at the access point. No sensitive, private information revealing the identity of the participant was collected. Data collection was limited to trip-related data and general characteristics of the visitors. Data collection was limited to daytime use. The distribution and collection locations opened at 10 am and closed at 6 pm. Tracking data that was stored on the GPS device was extracted in office at a later stage.In the next phase the spatial-temporal data was processed by evaluating, cleaning and validating the raw data. After that, the valid tracking data layers were projected in a Geographic Information System. In the following phase two types of drawings were made. The first type of drawings combines spatial-temporal data with e.g. an aerial image, access routes and arrival points, commercial activities, points of interest and investments. These drawings result in a visual analysis of the local spatial conditions in relation to actual behaviour of the tracked sample. The first type based on projection of the data on top of other geographical information and the second one based on density analysis of the data determined by the themes of the questionnaire.origin, familiarity, purpose and duration [age, gender and group type. These maps offer the possibility to visually compare spatial patterns for specific subgroups of participants.The second type of drawings delivers a set of specific spatial patterns based on the aspects of duration ,31 and a2.4.After a request from TU Delft, the municipality approached families in three neighbourhoods of the new town of Almere. Each family asked to participate in the research consisted of a father, a mother and one or two children in the age range of 16–18. This family constellation was chosen for the expected wide range of activity and movement patterns within one family unit. Initially, fifteen families agreed to participate. In the end, 40 participants of 13 families carried GPS devices for one week. The field work see  started During the week of data collection all tracking data was stored in the memory of the GPS device. The spatial-temporal data was stored at an interval of two seconds. On the eighth day after distribution, the devices were collected again during which a second interview took place and maps were drawn filling in blanks when devices were forgotten by participants. Hereafter, processing of both spatial-temporal and personal data started. The first step of processing was evaluation and cleaning. The second step was to split up tracks into trips based on each round trip from home. The third step was to enter the data in a database according to the developed protocol see . Once thIn Almere each member of 13 families was tracked for one week, covering several hundred trips. The data provides information about use of the network over periods of 24 hours, including starting and end time and length of a trip or activity, speed and transport modes of transportation, the radius from home or from activity locations. As expected, data collection encountered several problems that led to incomplete data: a lag in time to first fixation (fix) after leaving home, insufficient charging of batteries, forgetting or switching off GPS devices by participants. But a significant set of valid data remained for visual and quantitative analysis.3.3.1.In this section we show how the theory behind and the empirical results from the different research projects provide insight into the value of GPS as a sensor technology in urban studies. For both cases, the particular problem setting is described, followed by an explanation of analytical methods used in the context of that problem and how GPS tracking fits. Both case descriptions provide insight in the main measurements to be performed on GPS data to be relevant for that particular problem setting.3.2.Norwich, Rouen and Koblenz are relatively small cities  located in the United Kingdom, France and Germany, respectively. Each city has a historical centre and functions as a regional attractor serving a large hinterland. Concerned about future retail developments, the administrations of these cities struggle to keep up the vitality of their urban core as the central shopping district and in particular as an attractive place for living.The aim of the overall Spatial Metro project is to make investments in public space happen; in particular to improve the city centres for pedestrians. In this light, the role of TU Delft was to develop tools to measure the effects of the investments in for example city beautification, street furniture, lighting and information systems . Based oTU Delft developed and used two tools: (1) street interviews to collect information about the experiences of visitors (used in 2005 and 2006) and tracking technologies (GPS tracking) to collect data on actual movement and routing (used in 2007). Sixty-six people were interviewed in 2005. The interviews resulted in maps of great public spaces: ‘great to shop’, ‘great to enjoy’, ‘great to discover’ and ‘the greatest’. Further it resulted in an indication of gender, frequency of visit, age, origin, time spent, money spent, access mode and purpose.Using the GPS devices, in total 1,300 pedestrians were tracked and interviewed. On average 60% of the data was valid. The remaining 40% was not usable due to problems with fixation, batteries, blur (clouds of points) and fragmentation. The origin of these issues is clear: the signal reception in dense urban areas is weak; signals reflect on buildings, people tend to go into buildings, and pedestrians move relatively slowly . Also, Most insight gained from the experiment came from the spatial-temporal data adding another layer of information to the interview data and to the spatial analysis, providing in particular more insight in daily processes in the city. The combination with information exogenous to the GPS data, such as morphological maps, provides a technique to discover anomalies and to draw conclusions about qualities of public space. Density analyses offer a tool to discover ‘hotspots’ of use in the city based on actual movement, not on perception and post-hoc questionnaires. The use of a questionnaire offers a method to distinguish between trajectories on several different aspects, providing unique thematic maps and the ability to compare different aspects based on SPSS cross-tabulations. Finally, the use of dynamic maps for data visualisation offers temporal diagrams. These show not only trajectories, but also directions and flows of movement.Both static and dynamic ways of visualisation offer tremendous insight in pedestrian behaviour, leading to conclusions about differences in urban quality between places and about opportunities for improving the local situation, which can be applied in planning practice.To get the full picture, data collected using GPS should be used in combination with data on the location of programs, activities and points of interest, morphology and quality of public space, and with counting data. Placing counting devices in the right locations might provide a system to extrapolate the GPS sensor data.3.3.New towns have a number of generic characteristics. The plan to develop a new town is generally derived from an unambiguous socio-economic paradigm. The spatial layout and stratification of the circulating system, using subsystems of different speeds, is based on avoiding risk and conflict between transport modes and inhabitants. Most new towns lie within the influence sphere of an old, central city and often depend on it functionally. The plan for a new town often projects a particular life style, which projection is supposed to solve the social and spatial problems of the dominant central city. In general, new towns are built up in a short time with a simple or particular physical structure. The construction of housing in new towns conforms to market principles and relies on a fast and efficient building process for large groups of inhabitants that mostly originate from the central, dominant city. Almere is a morphologically polynuclear new town in the reclaimed land of the Flevopolder. The town exists of spatially separated suburban neighbourhoods. New towns in general and Almere in particular has attracted heavy criticism in the last decades with regard to mobility issues and quality of living, the need for renewal of some its parts, the (re)development of a city centre and the continuing planning tasks of housing construction.Over the last decade TU Delft developed and applied several spatial-analytical methods –37 to anurban life needs a ‘parallel’ organised urban frame.Secondly, this theory explains how the process of planning and construction of cities can be related to the physical structure of the urban frame. In particular, the factor time in the process of planning has a strong influence on the structure of public space, i.e. the structure of the urban frame and of parks and squares in the city. The theory distinguishes between urban systems that are organized as a ‘parallel’ system or as a ‘serial’ system ,38 see . The plaSo far, methods of analysis in Almere have focused on analysing the spatial structure, layout and process of planning. The GPS tracking experiment, part of ongoing studies on Almere, produces a new layer adding a mapping of actual behaviour to this analysis. This could contribute to substantiating or falsifying the theory on ‘parallel’ and ‘serial’ systems constructed of ‘frame’, ‘pattern’ and ‘circuit’.The problem for which GPS is used in the example of Almere is the following. In a ‘serial’ spatial urban frame there is often only one way to connect points of origin and destination, to connect the sequence of activities during a day. But, quality of life and the accommodation of multiple life styles demand a wider range of choice of possible routes, differing in time and space. The quality of urban life derives from coincidences, i.e. of ‘parallel’ use of the spatial urban frame, a condition for being related with others and other places in time and space. One possible measure of urban quality then is the degree to which round trips use the same route back and forth see .Another interesting measure made possible by tracking research is accumulated length of trip for particular purposes. The GPS tracking project in Almere made clear that in spite of an extensive pedestrian network and cycling network, parents transport their children to sport facilities during the week largely by car. Preliminary data analysis and extrapolation suggests that this might add up to a staggering total weekly amount of 800,000 to 1,200,000 km just for the city of Almere . Such daIn the case of Almere, there seems to be a partial paradox between the ‘serial’ process of planning the town resulting in a hierarchical structure of the urban frame and the crisscross way in which people use this urban frame by living in it day and night see . However4.TU Delft used GPS tracking technologies in two experiments on different scales and in different ways of device distribution. In this paper we aimed to assess the value of GPS as a sensor technology. The two different research projects described in this paper provide some insight there. The main question in this paper was: what is the value of GPS as ‘sensor technology’ measuring activities of people, in particular in the context of studies regarding urban quality? By looking at two different research projects by TU Delft using GPS, this question is answered in this section along three lines. Firstly, what is the contribution of GPS to traditional methods of urban research? Secondly, what is the performance of GPS as sensor instrument? Thirdly, in what ways can GPS-devices be deployed in urban settings?Traditional methods of research in urban design and planning are mostly visual in nature, such as morphological analysis, functional-spatial analysis, exploration of design alternatives, superimposition of thematic maps, etcetera. Although the interest in actual use of, in particular, public space has been present since the birth of the profession of urban planning, the actual use of methods studying it have remained limited. In the field of geography, the study of temporal-spatial patterns of use has developed, in particular in the field of time geography , but hasSo, the contribution of GPS to traditional methods of urban research can be valued from these three angles: visualisation, accuracy and the validation of other research techniques. Visualisation plays a very important role in dealing with tracking data. In the processing stage it is important in case of manual validation of data. In the interpretation and analysis stage it is important as a tool for analysis. And last, but not least, visualisation is instrumental in communicating research results from tracking studies both to experts across disciplinary boundaries and to non-experts such as politicians or civilians. The visual nature of tracking information makes it more akin to other research techniques in urban planning and design than previous research techniques to analyse people’s behaviour patterns in space and time. So, on the one hand the easily visualisable tracking data connects directly to the visual data used in urban planning and design – it can be literally layered on top of each other - while on the other hand it brings previously numerically and verbally oriented fields of knowledge into the language domain of urban planning and design. With regard to accuracy, GPS is proving to be significantly more accurate for registering routes and activity locations than post-hoc mapping or diary taking by participants. Moreover, research based on GPS tracking, and possibly in the future complete ‘urban sensor systems’, gives not only the possibility to visualise real-time behaviour. More important, it assists professionals in understanding and validating the performance of traditional urban analyses.Looking at these three angles on the value of GPS in relation to other methods of urban research, most important is that this knowledge provides new – visual, accurate and combinable - arguments and as such a new evidence base for projecting and predicting future urban developments.The performance of GPS as sensor instrument depends on a number of factors, both related to the technology and to factors outside the technological features. We highlight the importance of technological improvements, the scale of tracking studies, and the role of the experiment protocols.Technically and practically GPS tracking still has its problems and for research purposes further technological development is necessary. Increased quality of GPS-receivers and, for example, integration with other technologies such as the mobile phone system, is important to improve the quality of spatial-temporal data collection. Important technical issues are battery life time, time to (first) fix, accuracy of reception and avoiding blur and fragments. In addition to hardware improvements, software - such as scripts and data-mining algorithms - needs to be improved to further raise the quality and to speed up data processing.The experiments confirm the findings in Schaick and Spek  that scaThe cases show that data quality is not only dependent on the technical performance of the global positioning system. In the set up described in this paper, data quality very much relies on the parties involved. More than in the case of Spatial Metro, data quality in the Almere case is dependent on the involvement of the participants, as well as their commitment to and understanding of what they are doing. In comparison, data quality in the Spatial Metro case was heavily dependent on commitment and understanding of the experiments by research assistants. In the former the use protocols were most important, while in the latter the distribution protocol was essential to uphold data quality in the end, both with regard to technical issues as well as diminishing the risk of unusual routes taken by participants as a result of participating in the experiment. The extended time period in the Almere case enabled further support during the experiment such as a manual, a quick user guide and a 24/7 service desk).Our third criterion for valuing GPS as sensor technology is the possibilities it offers for deploying GPS-devices in urban settings. Technically, the experiments show – confirming the literature - GPS is not ideal in dense urban environments, for example because of loss of signal and reflections of the surfaces in urban environments. Furthermore, data completeness and accuracy suffers from people going in and out of buildings. Since GPS experiments are still dependent on distributing GPS devices that are carried by people or vehicles, urban environments do offer places such as car parks to control distribution of devices in a controlled setting, but the logistics of experiments are a limiting factor. Although these issues lead to a decreased amount of possibilities for carrying out tracking experiments, data validation still leaves a good portion of data. However, due the type of errors caused by deployments in urban settings, data processing in the experiments has proven to be a time consuming process.In general we conclude that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research. In both cases the GPS delivered spatial-temporal data next to background information gathered by a questionnaire. The spatial-temporal data delivered a new layer of information on top of other geographical information. The strong feature of the method is the combination of spatial-temporal data (behaviour in space and time), spatial conditions, social-demographic information of the participants and characteristics of the trips. This enables to split up patterns based on personal and trip related aspects. The methods, as developed by TU Delft, add information to the traditional ways of analysis and do therefore not a priori replace existing ways of collecting information, such as counting and observing. Still, the current experiments only show a small range of applications in comparison to what is possible, in particular to further study the qualities of public space in particular and of urban systems in general.5.To conclude this paper we would like to indicate a number of future developments in light of the experiments by TU Delft. We want to highlight the following developments: (1) the almost ubiquitous availability of geopositioning data in a nearby future, (2) the combination of positioning sensors with other types of sensors, (3) automation of data collection and processing, (4) the evaluative capacities of tracking technologies, and (5) the increased relevance of multiple, visual environments to communicate results from tracking studies.Firstly, the above section showed that the scale of experiments is limited considerably because of logistical and data processing concerns when using the current generation of available GPS devices. If GPS would be available wider and people could just share their tracks, the only thing needed is a platform and a set of protocols to upload spatial-temporal data. This would enable open-source collection of spatial-temporal data and therefore feature GPS as a worldwide applicable sensor technique collecting spatial-temporal data, quantitative information and qualitative information.Secondly, we foresee that combining GPS with other types of sensors, such as those measuring air quality, and sensory and emotional experiences of people would enable a next generation of tracking research to offer more directly applicable knowledge to the field of urban planning and design. This would require the development of new process architectures that combine several different data sets and the connection of data flows from stationary and mobile sensors.Thirdly, automatic recognition of individual track aspects is necessary to enlarge the scale of tracking experiments. Important variables with regard to individual tracks for which automation of data processing might be valuable are: (a) destination , (b) route , direction), (c) exit and access and direction with regard to a delimited research locale. With regard to the automatic recognition of collective, aggregate variables would be relevant: (a) flows of masses of people and (b) emerging shared destinations .Fourth, experts in tracking research and urban planners interested in these instruments foresee that GPS tracking can be used as a tool for evaluating the effects of interventions, i.e. the transformation of urban areas, or for continuous monitoring instrument of urban areas . HoweverLastly, in addition to the need for increasingly sophisticated data handling on the quantitative side of GPS-data analysis, visualisation remains in our view at the heart of the strength and relevance of using tracking technologies in urban studies. With this outlook, we see tracking studies evolving from the experimental stage to a full blown research instruments in a wide range of knowledge domains.


Family violence is a complex, multidimensional and pervasive presence in many Aboriginal communities. Although practitioners acknowledge that intimate partner violence (IPV) is a grave concern in the North, as in other jurisdictions in Canada, there is a paucity of literature about IPV and the local response to that violence.The purpose of this study is to report on a synthesis of Northern Territorial literature and a 3-year media watch conducted in the Canadian territories.This review is part of a multidisciplinary 5-year study occurring in the Northwest Territories (NT) and northern regions of the Prairie Provinces of Canada. The methods included a review of the literature through CINAHL, PubMed, Academic Search Complete, Social Sciences Index and JSTOR (1990–2012) combined with a media watch from 2009 to 2012. A thematic content analysis was completed.Themes included: colonization; alcohol and substance use; effects of residential schooling; housing inadequacies; help-seeking behaviors; and gaps within the justice system. Identified themes from the media watch were: murders from IPV; reported assaults and criminal charges; emergency protection orders; and awareness campaigns and prevention measures.When synthesized, the results of the literature review and media surveillance depict a starting context and description of IPV in the Canadian territories. There are many questions left unanswered which build support for the necessity of the current research, outline the public outcry for action in local media and identify the current published knowledge about IPV. Violence is intolerable and destructive to individuals, families, communities and to all societies. In the Canadian territories, as in other parts of the circumpolar world, intimate partner violence (IPV) is, unfortunately, well known to the people who live there. The effects of IPV are discussed publicly by local activists in the hope of obliterating its occurrence and yet whispered behind closed doors in some remote locations where relationships are intimately bound. The variables that increase the incidence of IPV are intermingled with the support, or lack thereof, as well as the uniqueness of Aboriginal and remote communities. Furthermore, these confounding variables as well as the micro and macro effects of IPV are traumatic and intersect private and public domains. There is a paucity of published academic literature about IPV in the Canadian north, but stories of charged perpetrators, victims and fatalities appear in abundance in the local newspapers. For that reason, the methods in this study combine a focused literature review with a media watch from 2009 to 2012.Similarities do exist between circumpolar countries especially in rural and remote areas where there are rugged terrains in isolated locations, arctic temperatures, isolation, small populations and limited resources. For that reason, the experience in the northern Territories of Canada may resonate with the IPV experience in other countries. The impact of the western world colliding with traditional values and lifeways along with colonization has disenfranchised people. These experiences may be felt across the circumpolar world. Furthermore, there is a need to explicate rural and remote context and experiences since the more prevalent urban interventions do not fit in the northern regions, which are distinctly different.This study begins with a background to both the definition of IPV and a context to the unique northern region within which services are provided to women and their children experiencing IPV. A description of methods utilized within the review is provided. The results of the systematic literature review and media watch are identified as well as considerations for practice, policy, research and education in the Canadian North.IPV is defined as coercive, harmful and abusive behavior, such as physical, sexual, emotional and/or psychological abuse, by a current or former partner within an intimate relationship . This inUnderstanding IPV as a health and social issue requires exploring the problem in context . The regThe territories have a significantly lower population in comparison to the provinces in Canada, which contradicts the incredibly vast geographic area that these 3 territories encompass. In 2011, the population of YT was 33,897, NT was 41,462, and in NU it was 31,906 . To furtFor example, in the NT there are 33 communities but at this time, only 5 have emergency housing shelters for women and families fleeing abusive situations. Also, these few shelters are not always able to provide services due to funding and/or staffing shortages. In addition to the paucity of shelter services, many women are required to leave their home communities to access assistance. This isolates them, not only from family support, but also from their culture. In addition to a severe lack of shelter services, 11 communities do not have Royal Canadian Mounted Police (RCMP) detachments. Subsequently, a violent incident in one of these communities may have women waiting hours for authorities to arrive.The low community populations within the NT, often only a few 100 people, have additional complexities to women experiencing IPV beyond a lack of formal services, or their less frequent use of them. The very short web of relationships within a community makes it difficult and uniquely complex in terms of accessing formal supports and/or services. For example, the abusive partner may be a relative of an important community leader or service provider, such as the local band council, employed at the Health Centre or local airport. These intersecting relationships can further complicate a woman's experience, willingness or ability to access services. It asks the question if indeed it may add to her fear, silence and success in fleeing a violent relationship.Aboriginal people encompass a huge proportion of the territories, with First Nations, Métis or Inuit people living in 85% of NU, 51% of NT and 23% of YT. We acknowledge that IPV is a form of violence against women, Existing literature on IPV specifically denotes family violence, spousal or domestic violence or IPV as a serious issue faced by Aboriginal women and more generally, within Aboriginal communities –10. “AboThe electronic databases used for this literature review included CINAHL with Full Text, PubMed, Academic Search Complete, Social Sciences Index and JSTOR using 2 different search engines Proquest and EBSCOhost (1990–2012). We also included a review of government documents, local reports and 2 dissertations relevant to the project. Keywords used included: domestic violence, family violence, IPV, spousal assault, battered women, violence against women and conjugal violence in the YT, NT, NU and Northern Canada. A secondary search through references within articles that met our selection criteria was also completed. Articles were selected if they met 2 particular criteria. First of all, articles were included that reported on research  results about IPV. Second, articles were included that provided results that occurred in the 3 territories and Northern provinces.Since there is very little published research from the Canadian Territories, we saw merit in expanding the accumulated data to include local sources of information and a review of media from 2009 to 2012. This included news and online reports from the Canadian Broadcasting Corporation (CBC) North and the 2 territorial newspapers. Keywords were used to search on-line news as well as a real-time surveillance of news reports. Newspaper articles were printed, collated and categorized by a central topic. Although non-academic, these documents add a context to what is publicly known or perceived about incidents in the Canadian North. From these, themes were assigned based on analysis of media collected over the 3-year period.This project has received ethical approval from the Research Ethics Board at the University of Regina and a research license from the Aurora Research Institute.In Canada, most IPV research has been concentrated within more southern and urban locations; little work has highlighted rural areas and/or the Canadian North. This changed in 2004 when Statistics Canada's General Social Survey (GSS) piloted a survey on victimization and collected data from residents in the NT, NU, and YT . Though Among Aboriginal people in Canada, family violence is a social issue that evolved as a consequence of social injustices and cultural oppression experienced with colonization . The higColonization not only transformed the geographical location of Aboriginal people but also shifted gender regime away from males, most obviously in the mid-1970s . DispropThe patriarchal nature of North American society was introduced with colonization. There was a shift from an egalitarian Aboriginal society, where men and women shared equal power in the subsistence economy, to the post-colonial society. Aboriginal men struggled to impose patriarchy amidst a socio-economic downturn as women became the main wage earners.Post-resettlement, Inuit women were more likely to embrace schooling and became employed outside the home. Among the Dene people, women were more likely to attain higher education, training and become the wage earners as compared to their male counterparts. Additionally, men's more traditional wage-earning roles, trapping and hunting, were experiencing a decline. This led to a situation wherein men were threatening violence to women who were expressing an interest in advanced education. Within Aboriginal families, post-colonial changes led to a power shift between genders as well as within gender roles, and contributed to the low self-esteem among Aboriginal males. In addition to esteem, increased rates of alcohol and substance use, depression and suicide were seen in men. Similar rates were also seen in Aboriginal women and attributed to both the cultural changes since colonization as well as socio-economic factors such as family violence . Durst  attributKorhonen  describeMany women who experience IPV have histories of substance abuse; alcohol and drug abuse had been linked as both a predisposing and aggravating factor to IPV in Aboriginal communities . The incThe residential school experience of Canada's Aboriginal people has been identified as a contributing factor to IPV . The hisOne critical issue that continuously challenged community response to IPV is housing. Housing inadequacy and overcrowding has been closely linked to IPV in Northern Canada . AdditioIn general, it is highly unlikely that families report violence that happens within the home or involve resources outside the home with what is usually considered a private matter ,11. IPV Recent studies on help-seeking rates for IPV in Canada had shown that although Aboriginal women are more likely to be abused by their partners than non-Aboriginal women, the rates of help-seeking are similar . The likIn the NT and YK, a civil legislation targeting family violence including IPV was initiated . The intAlthough media reports may hold certain biases and/or personal opinions, they are a source of information that is useful to examine in terms of occurrences in the North and the response and reaction to these elicited events. Themes from the data include reported murders from IPV, reported assaults and criminal charges, emergency protection orders (EPOs) and awareness campaigns and prevention measures.Murdered women and children in the past 3 years have accounted for the deaths of 5 women and 2 children in the NT and NU in 5 violent incidents, respectively. The first homicide in this timeframe in 2009 was a Dene woman living in the remote community of Gameti, NT who was beaten to death by her husband. The perpetrator received a 7-year sentence for manslaughter. The NT Coroners report was released in 2012 with recommendations related to the death . Second,Although this is not a comprehensive review of the media, there were 15 assaults and criminal charges directly noted to be IPV reported in the Northern newspapers during this period of time. The contexts are varied but do provide descriptions of the nature of IPV in the territories. A few examples of particulars extrapolated from the clippings are included here that suggest that children are sometimes present; substance  is a factor; holiday celebrations may be a factor; the perpetrators were often repeat offenders; weapons can include anything in the near vicinity of the outburst—telephones, fists, feet, knifes, rifles, fire; and in some cases family were called for assistance.The woman told police that her spouse had forcibly held her down on a bed and “at one point forced her eye open” said Aitken. The woman crawled into the crib of the couple's 16-monthy-old son and was holding the child when her spouse tried to pull her out. When he couldn't, he slapped her across the face. Aitken told the court the man would not allow his spouse to leave or use the phone. She eventually was able to call her family in Inuvik and alert them to the situation. She then “hid in the bedroom until the police arrive” said Aitken. The captions are interesting and perhaps sensationalized to grab the reader's attention. One reporter wrote the following:The media has also reported both satisfaction and dissatisfaction with EPOs. EPOs have been in place for close to a decade. EPOs were initiated in the NT to provide safety and protection from intimate partner perpetrators by inhibiting their access to their partner where there is evidence of abuse and violence. The RCMP enforces the EPO following judicial authorization. Some reports indicate that women are fearful of RCMP believing that RCMP do not always respond to the immediate needs of women or that when they do there is a prejudiced overtone to the response . One manThe literature on IPV in the NT is scant, which is not unexpected since the location itself is mostly remote and under-resourced. However, it is this very remoteness and scarcity of resources that add to the complexity and the compounded effects that are experienced by families and whole communities who are intimately bound to each other. Although there is not an abundance of literature, researchers have focused on studying the aetiology, attributes, consequences of IPV and gaps in services. This broadens our understanding of some aspects of IPV. For example, knowledge is elucidated to identify influences of colonization, residential school and housing inadequacies on the creation of unhealthy environments. Whereby, violence culminates from suffering and pain too great to bear or where shame and blame become normalized in intergenerational dysfunction. Gaps in the service are also exposed. For example, the mental health needs of a colonized population and underserviced places are notably present but solutions are not readily available or identifiable. Researchers are skimming the surface of the issue as attempts are made to provide explanations of IPV in Northern Canada that lead to concrete efforts to care for residents and manage the effects of IPV. This is not enough. There is a need for a more comprehensive research agenda.It is evident that social determinants of health, for example housing inadequacies, do not act in isolation, rather they are interwoven factors with poverty, unemployment, low literacy, etc. affecting territorial people and contributing to stressful living. In addition, the historical context of colonialism and male-dominated societies has created a volatile and oppressive milieu for women. Since the variables that appear to influence IPV are multifactoral, it is acknowledged that a comprehensive approach to both the investigation of IPV and the analysis of the data is required.This study has offered a targeted literature review of IPV in Canada's NT along with the results of a 3-year media watch. The themes from the published literature are contextually enhancing our understanding of both the IPV experience and the circumstances of those experiences. Colonization, alcohol and substance use, effects of residential schooling, housing inadequacies, help-seeking behaviors and gaps within the justice system are all explanatory to IPV. Media reports provide a perception of events surrounding homicides, assaults and charges to perpetrators as a result of IPV and also describe current interventions, such as EPOs and public awareness campaigns. The synthesis contributes to circumpolar knowledge of IPV.It is important to note that there are existing resources provided in all 3 territories through government departments , and policing services. The Coalition against Family Violence, led by the NT Status of Women, has been instrumental in influencing policy direction with the government and in public awareness of zero tolerance to violence. Most recently, the Department of Justice in the NT has created a 9-month programme for male perpetrators of violence that is offered through the Healing Drum Society. Education sessions have been offered for police and front-line workers. Narrative therapy sessions are currently provided to assist counsellors. These activities are making a difference to local families.This review illuminates the need for further investigation and action to eradicate violence in the North. Furthermore, the elevated number of IPV incidents indicates the need for establishing healthy relationships essential for healthy families, communities and societies, for productive and fully functioning growth and development, and for civility and peace within our homes and homelands. Finally, we can surmise that if violence were eradicated the environment at all levels  would be more conducive to happy and whole communities.


Pre-operative planning and intra-operative guidance in neurosurgery require detailed information about the location of functional areas and their anatomo-functional connectivity. In particular, regarding the language system, post-operative deficits such as aphasia can be avoided. By combining functional magnetic resonance imaging and diffusion tensor imaging, the connectivity between functional areas can be reconstructed by tractography techniques that need to cope with limitations such as limited resolution and low anisotropic diffusion close to functional areas. Tumors pose particular challenges because of edema, displacement effects on brain tissue and infiltration of white matter. Under these conditions, standard fiber tracking methods reconstruct pathways of insufficient quality. Therefore, robust global or probabilistic approaches are required. In this study, two commonly used standard fiber tracking algorithms, streamline propagation and tensor deflection, were compared with a previously published global search, Gibbs tracking and a connection-oriented probabilistic tractography approach. All methods were applied to reconstruct neuronal pathways of the language system of patients undergoing brain tumor surgery, and control subjects. Connections between Broca and Wernicke areas via the arcuate fasciculus (AF) and the inferior fronto-occipital fasciculus (IFOF) were validated by a clinical expert to ensure anatomical feasibility, and compared using distance- and diffusion-based similarity metrics to evaluate their agreement on pathway locations. For both patients and controls, a strong agreement between all methods was observed regarding the location of the AF. In case of the IFOF however, standard fiber tracking and Gibbs tracking predominantly identified the inferior longitudinal fasciculus that plays a secondary role in semantic language processing. In contrast, global search resolved connections in almost every case via the IFOF which could be confirmed by probabilistic fiber tracking. The results show that regarding the language system, our global search is superior to clinically applied conventional fiber tracking strategies with results similar to time-consuming global or probabilistic approaches. The neurological network of the human brain comprises complex functional units such as the language system, which consists of multiple functional areas connected via white matter pathways. These subcortical networks are of major interest for pre-operative neurosurgical planning and intra-operative guidance close to eloquent structures to prevent neurological deficits such as post-operative aphasia.Insight into the general architecture of the language system is provided by various anatomo-functional connectivity studies with invasive and non-invasive techniques. Intra-operative subcortical mapping (ISM) locates pathways by inducing temporal neurological dysfunctions with electrical stimulation Both types of functional connectivity studies have been supplemented by diffusion tensor imaging (DTI) local and global approaches are required:For the detection of language related white matter tracts, ISM can be applied during awake surgery. In such a procedure, the patient undergoes repetitive language testing while the subcortical surface of the resection cavity is being stimulated. This invasive method can also be used to verify the results of DTI fiber tractography Several local approaches based on the principle of fiber tracking such as streamline propagation (SP) In contrast, global approaches consider a larger subspace of the diffusion tensor field at once to infer global characteristics of the diffusion process and to model uncertainty in the diffusion data. For instance, fast marching methods evolve a diffusion front according to the underlying tensor profiles and compute fibers with an assigned level of confidence by backward processing based on gradient descent Either of these global approaches computes fibers or probability maps of high quality, however, the computational effort is beyond a clinically acceptable time frame. Other global approaches introduce the concept of target-orientation explicitly by reconstructing connections between two predefined ROIs. This reduces the amount of data while the level of quality is maintained. The guided fiber approach * shortest path algorithm, whose time complexity is optimal Our previously presented approach In this work, GS was compared with the aforementioned fiber tracking algorithms, SP and TD, which are commonly used in clinical practice To evaluate the reconstruction capabilities of the considered methods, two neuronal pathways, the arcuate fasciculus (AF) and the inferior fronto-occipital fasciculus (IFOF), were selected. These pathways are of particular interest for neurosurgical interventions as they connect the Broca and Wernicke areas by a dual route that is part of the language processing system. The AF, which is a part of the superior longitudinal fasciculus, is generally regarded as the dorsal language pathway responsible for phonological processing Despite of this controversy, the IFOF was selected to challenge the above tractography approaches as its reconstruction in the context of semantic language processing has been shown to be a difficult task. A combined fMRI and DTI study for language relevant cortical sites and white matter pathways of healthy subjects identified problems of fiber tracking to reveal the terminals of the IFOF in the middle temporal gyrus that are relevant for semantic processing For this purpose, fiber tracts reconstructed by all methods on image data of both patients undergoing tumor surgery and healthy controls were assessed by a neuromedical expert under the qualitative aspect of anatomical feasibility. Then, the agreement of the reconstruction methods on the location of neuronal pathways was evaluated quantitatively by distance- and diffusion-based similarity metrics. In addition, all methods were validated on ground-truth data of simulated DTI software phantoms comprising fiber configurations of varying complexity.This study was approved by the ethics committee of the University of Erlangen-Nuremberg according to the ethics committee proposal number 3578. This included all clinical investigations with pre- and intra-operative MRI and functional neuronavigation, and subsequent data analyses for all patients and controls. Written informed consent was obtained from all patients and controls. All clinical investigations were conducted according to the Declaration of Helsinki.Image data originated from 25 right-handed patients  equipped with a gradient system with a field strength of up to 40 mT/m (effective 69 mT/m) and a slew rate of up to 200 T/m/s (effective 346 T/m/s).During the acquisition of functional data using fMRI, visual stimulation was performed because of the reduced signal-to-noise ratio as compared to auditory stimulation. For each subject, 30 rest and activation measurements were obtained according to a block paradigm (“boxcar”) with a total duration of 15 minutes. Activities included reading, naming of objects, answering questions and inferring verbs and sentences from given nouns The functional data was acquired using an echo-planar imaging (EPI) sequence  that correspond to the Broca and Wernicke areas. These areas could be determined for all subjects successfully and were selected as ROIs for all tractography approaches.2, b2, field of view 240 mm, 1500 Hz/Px bandwidth, measurement time: 5 min and 31 sec). For each slice, five measurements were acquired and averaged by the MRI scanner. The image resolution was 3. One reference image without diffusion sensitization as well as six images with diffusion sensitization in non-collinear directions were obtained according to the oblique double gradient encoding scheme   with a resolution of Additionally, if the tumor exhibited contrast enhancement on the preoperative images, the T1-weighted axial spin echo sequence was repeated after intravenous application of contrast media (0.2 ml/kg gadolinium diethylenetriamine penta-acetic acid). In nonenhancing tumors, an additional T2-weighted turbo spin echo sequence  was acquired.To validate the fiber reconstruction methods on ground-truth data, three DTI software phantoms were selected from a database with fiber configurations of different complexity including branching and kissing pathways as well as a spiral with more than three turns According to a study on the influence of signal-to-noise ratio (SNR) on the pathway reconstruction * shortest path algorithm is then defined by accumulating the negative proportional function The approach of GS to anatomical connectivity In this work, this cost function is extended in two ways: At first, the divergence irection  is incorsotropy   [6] to stropy  ( .(1)(2)The cost function is additionally supported by thresholds for the maximum bending angle between adjacent fiber segments and the minimum FA value at sample points. Thereby, the reconstruction of anatomically unlikely fibers of strong curvature or of fibers intersecting isotropic regions can be avoided. Moreover, anatomical knowledge can be incorporated to reconstruct specific pathways by restricting the search space to an adjustable bounding box. This is especially useful for the dual route of the language system, since anisotropic diffusion is different along the AF and IFOF The algorithms SP and TD evaluated in this study are clinically approved and implemented in various DTI applications Fibers are propagated in both ortho- and retrograde directions and are terminated as soon as the FA value drops below a predefined threshold. To propagate fibers from the current location, different schemes are applied by SP and TD: In case of TD, the diffusion tensor is multiplied with the fiber direction of the previous fiber segment to obtain the next fiber point. In regions of high anisotropy, fibers are deflected towards the major eigenvector, whereas in isotropic regions, the incoming direction is maintained or only slightly affected by the tensor Several similarity metrics for reconstructed fiber tracts were proposed in the literature, which are either applied to cluster fibers or to evaluate approaches for pathway reconstruction by comparing the divergence of fibers from ground-truth data or from the results of other methods. In general, the similarity of two fibers can be quantified by their spatial displacement The spatial similarity of the resulting fiber tracts ined as  , measureed as  . If the first point of these closest point pairs is denoted as Secondly, overlapping fiber segments have to be identified to avoid biasing of the similarity metric, as fibers of GS terminate in ROIs, whereas fibers of SP, TD and GibbsT are not restricted by them. For two fibers (bottom), more fiber segments than necessary would be excluded. Therefore, the trimming approach was extended as follows: Again, the two closest point pairs at each end are considered, but trimming is applied to at most one of the fibers at each end under the condition that only one of the closest point pairs refers to an intermediate point, while the other refers to an end point.This approach is suited to cut protruding endings of otherwise coherent fibers, as the overall structure of the fibers is not altered. However, in case of diverging fibers as illustrated in In addition to geometric properties, similarity in terms of diffusion is evaluated for each pair of fiber tracts as   to reveaFor detailed assessment of the capabilities to reconstruct anatomically feasible fiber tracts in the presence of nearby tumors, the clinically approved methods SP and TD, and the global approaches GibbsT and GS were compared with each other using the similarity metrics defined above. These methods were additionally compared with ConProb by visually assessing the overlap of the fibers with the probability maps.All methods were applied in native space for direct comparison. Fiber tracking in standard space, provided by a registration method capable to deal with tumor data, was not applied because this study is intended to provide results of direct relevance for state-of-the-art neurosurgery.After an evaluation of SP, TD, GibbsT and GS using DTI software phantoms, all methods were applied on two pathways of the language system, the AF and the IFOF. Details about the parameters and adjustments to the connectivity problems for either method are presented in the following: Generally, for both the simulated and the image data, the step length of SP and TD was set to 0.5 mm. The search space of GS was defined by a cubic grid with 74 neighboring points and an average step length of GS to 2 mm, resulting in a smallest and largest step length of 1.3 and 2.3 mm, respectively. The threshold on the bending angle of GS was set to For the software phantoms, ROIs covering the full diameter of the fiber tracts were manually positioned at both ends of the simulated pathways. As the diffusion characteristics were different for each DTI phantom, FA thresholds were defined individually and set to For the experiments based on image data of patients and healthy controls, ROIs corresponding to the speech areas obtained by fMRI were defined. The fibers created by SP and TD were separated into the dorsal and the ventral pathway by two manually defined ROIs placed at the middle of each tract.Due to the aforementioned drawbacks of deterministic fiber tracking methods in regions of low FA, they may not succeed in locating a connection between these ROIs. Therefore, two modifications to the parameters and ROIs were applied: At first, tracking was performed with FA thresholds of 0.25 and on failure with 0.2. Secondly, ROIs were incrementally expanded by at most 4 voxels or 7.6 mm in each dimension until a connection was found with either FA threshold. In the following, this process is denoted as ROI padding. The decision rule about which fiber tract to select for the similarity metric was defined as follows: If fiber tracking with an FA threshold of 0.25 required no more than two additional ROI paddings as compared to fiber tracking with an FA threshold of 0.2, the fiber tracts with FA threshold of 0.25 were used. Otherwise, the fiber tracts with FA threshold of 0.2 contributed to the similarity value.GibbsT was applied using the MITK implementation as presented in The fiber reconstruction itself was applied using the following parameters: Regarding ConProb, connection probability maps for both ROIs (without padding) were generated in the Matlab-based DTI & FiberTools In order to search for anatomical connections with GS, the bounding box was manually placed for both the AF and IFOF by considering anatomical features and activation centers. In case of the AF, the bounding box was placed to include the white matter of the left hemisphere without the rostral part of the temporal lobe. Regarding the IFOF, the upper boundary of the bounding box was placed above the frontal horn of the lateral ventricle, and the inner boundary directly medial to the external capsule. In all cases, the FA threshold was initially set to 0.3 and reduced to 0.15 in case of failure. In contrast to SP, TD and GibbsT, ROI padding was not applied for GS.Prior to statistical evaluation, each pair of reconstructed fiber tracts was inspected visually to ensure that the expected anatomical space of the language site is covered. For this purpose, the neuromedical expert (coauthor A. Z.) investigated slices of the T1 MR images with an overlaid display of fiber tracts, fMRI activation clusters, and tumor segmentation (if applicable) as illustrated in The evaluation of the methods on ground truth data using DTI phantoms is presented in the next section. The results of the evaluations carried out on the controls with unaffected brain anatomy are explicated in the second section, on the brain tumor patients in the third section.For a qualitative evaluation on simulated data, success and failure to connect the ROIs was assessed in a first step. All methods successfully reconstructed branching and kissing pathways for images with both SNR 15 and 30, leading to similarity results. In case of the simulated spiral, only about two thirds of the first cycle was covered by SP and TD before the fibers terminated at the border of the pathway . Fiber sBased on the previously defined similarity metric On image data of control subjects, both SP and TD were able to reconstruct neuronal pathways, although relaxation of the FA threshold and incremental ROI padding had to be applied in some cases to obtain fibers. In one case, the FA threshold had to be reduced to 0.2 for the ventral pathway. For the remaining fibers along the ventral and all fibers along the dorsal pathway, an FA threshold of 0.25 was sufficient. The ROIs were padded on average by 0.17 and 0.67 voxels for the dorsal and ventral pathways, respectively. GibbsT established dorsal and ventral connections in all cases with an average ROI padding of 0.17 and 3.33 voxels respectively. Similarly, GS could establish dorsal and ventral connections in all control subjects with an FA threshold of 0.3.After visual inspection, the fiber tracts generated by all methods along the dorsal pathway were confirmed to follow the AF anatomically in all cases of the control group. Regarding the match between the ventral fibers and the anatomy of the IFOF, GS was successful in all cases, while SP and TD established connections along the correct pathway in five and three cases, respectively. In the remaining cases, at least one of the methods reconstructed fibers corresponding to the ILF. Similar results were created by GibbsT for the ventral fibers. Here, fibers did not match the IFOF, but the ILF for all cases which is exemplified for the control patient in For the control group, complete agreement of all methods was found for the AF, whereas less matching pairs between GS and SP and between GS and TD were found for the IFOF, and none for GS and GibbsT. Regarding the geometric similarities along the AF, fiber tracts of GS and SP were on average closer than of GS and TD and of GS and GibbsT. Along the IFOF, fiber tracts of GS and TD were closer than those of GS and SP. For GibbsT, no fiber was found for the IFOF.To elucidate the effect of methods on FA, values of In the patient group, SP and TD depended more on the relaxation of the FA threshold and incremental ROI padding. In all but four cases, an FA threshold of 0.25 enabled reconstruction along dorsal and ventral pathways, in the remaining cases a relaxation to 0.2 was required for both pathways. The average paddings by SP and TD were 1.0 and 0.81 (at most 3) voxels for the dorsal, and 1.63 and 1.33 (at most 4) voxels for the ventral reconstruction. GibbsT established dorsal and ventral connections in 14 and 11 cases with an average ROI padding of 2.07 and 3.09, respectively.GS reconstructed the dorsal phonological pathway in all but four patients with an FA threshold of 0.3. The remaining cases had either tumors of WHO grade III or IV, or the distance between pathways and the tumor was smaller than 5 mm. By reducing the FA threshold to 0.15, connections could be found in these cases as well. For the ventral semantic pathway, fiber tracts were found by GS in all but two patients with an FA threshold of 0.3. In the remaining cases, patients with a WHO grade IV tumor in the left temporal lobe and a WHO grade II tumor in the temporal stem, GS applied with an FA threshold of 0.15 found no fiber tracts.After visual inspection, the fiber tracts along the dorsal pathway were confirmed as anatomically feasible in the majority of all patients for SP, TD and GibbsT: 15, 17 and 14 out of 25 cases with ROI padding averages of 1.0, 0.81, and 1.64 respectively. The results of GS were confirmed to follow the AF for all subjects in the patient group.In contrast to the positive results obtained for all methods dorsally, fiber tracts reconstructed by SP and TD along the ventral pathway correlated in some cases with the ILF rather than the IFOF. This problem becomes apparent in By replacing the frontal ROI with the rostral part of the external capsule, the focus of SP and TD could be changed to the IFOF. However, even after this modification, only some fiber tracts with anatomical correspondence to the IFOF could be reconstructed. Regarding the anatomic feasibility of the results of GS, all successfully reconstructed fiber tracts followed the trajectories of the IFOF.For only one case, ventral fibers of GibbsT followed the IFOF (ROI padding of 3), and the ILF in eight cases (average ROI padding of 2.7) which is shown for the patients in Apparently, when observing the results in Regarding the comparison of diffusion values, higher average FA values were observed along the AF than along the IFOF in all compared fiber tract pairs except for the pair GS and GibbsT  and timings were recorded for each subject including loading of data and ROIs, preprocessing such as computation of the diffusion tensors, execution of the methods and automatic filtering with ROIs. SP and TD required between 5 and 10 minutes, and GS took 20 minutes on average. The computation of the connection probability maps amounted to between 15 and 45 minutes. In contrast, the optimization of the Gibbs tracking approach took about two hours.In this study, five different methods for reconstructing neuronal pathways of the language system were compared: GS and GibbsT as representatives for global approaches, two clinically applied fiber tracking techniques, namely SP and TD, and ConProb, a connection-oriented probabilistic tractography approach.For the simulated DTI data, GS was able to obtain valid fiber tracts for all configurations, whereas SP, TD, and GibbsT failed to determine connecting fiber tracts in case of the spiral. This clearly indicates the methodological advantages of GS for connectivity problems with known start and end regions. The relatively large spatial deviation between GS and SP or TD can be explained by the grid dependency of GS that becomes obvious as the alignment is improved with grids of higher angular resolution.Regarding the pathways in the image data, smaller numbers of corresponding pairs of fiber tracts and generally higher distance values were observed for the IFOF as compared to the AF. In addition, average FA values along the IFOF were significantly lower in comparison to the AF. This explains the weaker agreement between the considered methods on the location of the IFOF, and implies that this pathway is more difficult to reconstruct. An additional explanation for these difficulties might be a lower diameter of this pathway and the associated risk to lose track more easily.In general, a stronger agreement between methods was observed in controls compared to the brain tumor patients as shown by fewer excluded fiber tract pairs. These results clearly indicate the influence of tumors on white matter tracts, which is also reflected by smaller FA values in the presence of nearby tumors. This is a possible reason for the more complicated reconstruction of feasible fibers in brain tumor patients, which is also in line with the detailed analysis of the influence of tumors on FA values in With respect to methods, the application of probabilistic fiber tracking Regarding the strong concept of Gibbs tracking, the results for the dorsal pathway strongly correlated with the results of the other methods. This is in line with a successful application of this method on different tract systems of the brain Regarding the global search, SP and TD, slightly better average FA values were observed for GS than for SP or TD, which might be due to the inclusion of FA into the cost function. As a result, the search space is preferably expanded to regions with higher anisotropic diffusion, which may result in fibers located closer towards the center of pathways.While GS was able to reconstruct the AF and in particular the IFOF with initial settings in most cases, both SP and TD required a reduction of the FA threshold and padding of the ROI volume in order to establish a connection at all. Moreover, visual inspection of fiber tracts resulting from reconstruction with SP and TD showed a tendency to erroneously reconstruct fibers along the ILF rather than along the IFOF. The difficulties of both deterministic approaches to reconstruct the AF, and the IFOF in particular, can be attributed to the design of the algorithms, which only take the local tensor information into account for fiber reconstruction. Especially for pathways with multiple terminations such as the IFOF On the other hand, global approaches like GS make use of the entire tensor information and establish connections which are optimal in respect of the available diffusion data between two ROIs. The underlying concept of cost minimization is justified since it is anticipated that functional areas are connected by preferably short and direct pathways as a result of the morphological evolution of white matter pathways in the brain However, since GS avoids time-consuming computations, it can be considered as a compromise between these approaches and deterministic fiber tracking. As anatomical connectivity can be resolved with sufficient accuracy and results are provided in a fast way, GS is well suited for clinical application. In particular, in combination with DTI protocols that acquire smaller numbers of gradient images and with clearly defined start and end ROIs located by fMRI Despite of its considerable advantages, one limitation of the GS approach remains. In case of functional areas that are connected via multiple alternative pathways, GS requires anatomical knowledge to appropriately define the search space with the bounding box. However, as this mechanism can be used to draw the focus to either pathway, GS is the superioralternative to investigate anatomical connectivity, since SP and TD are not able to take advantage of such an approach.In this study, two deterministic approaches to fiber tracking, streamline propagation (SP) and tensor deflection (TD), a dedicated approach for anatomical connectivity analysis (GS), Gibbs tracking (GibbsT) and a connection-oriented probabilistic tractography approach (ConProb) were compared with respect to their capability to reconstruct neuronal pathways of the language system. Based on DTI data of a patient group with supratentorial tumors close to pathways and functional areas, and of a control group, two pathways of the semantic system were considered. In addition to visual validation based on anatomical knowledge, the evaluation of diffusion values and distances between fiber tracts showed that GS produces superior results as compared to SP, TD, and GibbsT. In particular, the ventral language connections via the IFOF were revealed by GS in most cases which was in line with the probability maps of ConProb. In contrast, SP, TD, and GibbsT often failed with standard settings for ROIs and thresholds on fractional anisotropy (FA). Despite relaxation of FA thresholds and expansion of ROIs, SP, TD, and GibbsT still failed in some cases. Overall, GS proved to be more reliable with less failures and less adjustments required.