Background Within the field of renal transplantation there is a lack of qualified and trainee surgeons and a shortage of donated organs. Any steps to tackle these issues should, in part, be aimed at future doctors.
Background
Within the field of renal transplantation there is a lack of qualified and trainee surgeons and a shortage of donated organs. Any steps to tackle these issues should, in part, be aimed at future doctors.Methods A questionnaire was distributed to final year students at a single medical school in the UK to assess their exposure to and knowledge of renal transplantation.
Methods
A questionnaire was distributed to final year students at a single medical school in the UK to assess their exposure to and knowledge of renal transplantation.Results Although 46% of responding students had examined a transplant recipient, only 14% had ever witnessed the surgery. Worryingly, 9% of students believed that xenotransplantation commonly occurs in the UK and 35% were unable to name a single drug that a recipient may need to take.
Results
Although 46% of responding students had examined a transplant recipient, only 14% had ever witnessed the surgery. Worryingly, 9% of students believed that xenotransplantation commonly occurs in the UK and 35% were unable to name a single drug that a recipient may need to take.Conclusions This survey demonstrates a lack of exposure to, and knowledge of, the field of renal transplantation. Recommendations to address the problems with the recruitment of surgeons and donation of organs, by targeting medical students are made.
Conclusions
This survey demonstrates a lack of exposure to, and knowledge of, the field of renal transplantation. Recommendations to address the problems with the recruitment of surgeons and donation of organs, by targeting medical students are made.

Background With the potential for improved quality of life and increased life expectancy, renal transplantation is the first choice treatment for most patients with end-stage renal failure [ 1 , 2 ]. However, in the UK there is an ever-increasing disparity between the number of patients on the waiting list and those being transplanted [ 3 ]. This is predominantly due to a rise in the incidence of renal failure amongst an aging, racially diverse society in conjunction with a shortage of donated organs [ 4 ]. The field of renal transplantation also suffers from a lack of surgeons. Indeed, it is predicted that by the year 2005 there will a shortage of over twenty consultant renal transplant surgeons [ 5 ]. Any measures to deal with these problems must include educating and attracting the doctors of tomorrow; medical students [ 6 , 7 ]. However, the General Medical Council's core curriculum model for undergraduate teaching has lead to significant changes in the way that specialist subjects are taught [ 8 ]. This survey was conducted to assess the exposure to, and knowledge of, renal transplantation amongst medical students at a single medical school in the United Kingdom.
Background
With the potential for improved quality of life and increased life expectancy, renal transplantation is the first choice treatment for most patients with end-stage renal failure [ 1 , 2 ]. However, in the UK there is an ever-increasing disparity between the number of patients on the waiting list and those being transplanted [ 3 ]. This is predominantly due to a rise in the incidence of renal failure amongst an aging, racially diverse society in conjunction with a shortage of donated organs [ 4 ].The field of renal transplantation also suffers from a lack of surgeons. Indeed, it is predicted that by the year 2005 there will a shortage of over twenty consultant renal transplant surgeons [ 5 ].Any measures to deal with these problems must include educating and attracting the doctors of tomorrow; medical students [ 6 , 7 ]. However, the General Medical Council's core curriculum model for undergraduate teaching has lead to significant changes in the way that specialist subjects are taught [ 8 ]. This survey was conducted to assess the exposure to, and knowledge of, renal transplantation amongst medical students at a single medical school in the United Kingdom.Methods In July 2003 a PRHO job fair was held for final year medical students of Bristol University, which all 140 students within the year attended. An anonymous questionnaire was distributed to every student, after the aims of the study had been explained, at the end of a series of short lectures. (Figure  1 ). The questionnaire consisted of six questions, three to assess their exposure to the field and three to assess their knowledge. The form was collected immediately upon completion, with no opportunity to confer. Figure 1 Questionnaire distributed to the students. The questionnaire had been piloted on a random sample of thirty final year medical students from the year before, whereby the form was distributed electronically to their University email accounts. This confirmed that the length and wording of the questionnaire, and the level of knowledge required to complete it were appropriate for the target population. All statistical analysis was performed using the chi square test, with a p value of 0.05 or less taken to demonstrate statistical significance.
Methods
In July 2003 a PRHO job fair was held for final year medical students of Bristol University, which all 140 students within the year attended. An anonymous questionnaire was distributed to every student, after the aims of the study had been explained, at the end of a series of short lectures. (Figure  1 ). The questionnaire consisted of six questions, three to assess their exposure to the field and three to assess their knowledge. The form was collected immediately upon completion, with no opportunity to confer.The questionnaire had been piloted on a random sample of thirty final year medical students from the year before, whereby the form was distributed electronically to their University email accounts. This confirmed that the length and wording of the questionnaire, and the level of knowledge required to complete it were appropriate for the target population.All statistical analysis was performed using the chi square test, with a p value of 0.05 or less taken to demonstrate statistical significance.Results Questionnaires were completed by seventy-six of the 140 medical students in the year (54%). Of these responding students, thirty-two (42%) had never completed either a general medical or general surgical placement at one of the two centres for renal transplantation within the region, both of which are affiliated to the University of Bristol. National data of renal transplantation activity shows that these two centres differ in the number of transplants performed each year [ 3 ]. Over the 2002/3 and 2003/4 period Southmead Hospital, Bristol performed approximately three times as many transplants per year than Derriford Hospital, Plymouth (2002/3: 101 in Bristol, 36 in Plymouth, 2003/4: 132 in Bristol, 42 in Plymouth). Sixty-five students (86%) had never been in the operating theatre during a renal transplant. Of the eleven students that had witnessed a transplant the majority, seven, had been unscrubbed (9%). One student had been scrubbed and observing and a further three students (4%) had actually assisted with the procedure. Closer analysis of these eleven students demonstrates that only one of the eleven had been on placement at Derriford Hospital (χ 2 , p = 0.006). Thirty-five (46%) of the students had examined a patient with a transplanted kidney but only thirty-three (43%) could accurately draw on a diagram the usual site of surgical incision that would be made on someone undergoing a left sided renal transplant. Interestingly, fourteen of the students that claimed to have examined a transplant recipient were unable to accurately draw the site of incision. Of the students that had examined a transplant recipient twenty-two had been on placement at one of the hospitals with transplant centres and thirteen had not (χ 2 , p = 0.128). Fifty students (66%) were aware that in addition to the use of organs from brain stem dead donors, kidneys could also be transplanted from living donors. Eighteen students (24%) could not name any additional sources of organs and seven (9%) thought that xenotransplantation, using porcine kidneys, is carried out in the UK. None of the students suggested non-heart beating donation. Nineteen students (25%) were unable to name a drug that might be taken by a patient with a renal transplant. Twenty-one students (28%) were able to suggest just one.
Results
Questionnaires were completed by seventy-six of the 140 medical students in the year (54%). Of these responding students, thirty-two (42%) had never completed either a general medical or general surgical placement at one of the two centres for renal transplantation within the region, both of which are affiliated to the University of Bristol. National data of renal transplantation activity shows that these two centres differ in the number of transplants performed each year [ 3 ]. Over the 2002/3 and 2003/4 period Southmead Hospital, Bristol performed approximately three times as many transplants per year than Derriford Hospital, Plymouth (2002/3: 101 in Bristol, 36 in Plymouth, 2003/4: 132 in Bristol, 42 in Plymouth).Sixty-five students (86%) had never been in the operating theatre during a renal transplant. Of the eleven students that had witnessed a transplant the majority, seven, had been unscrubbed (9%). One student had been scrubbed and observing and a further three students (4%) had actually assisted with the procedure. Closer analysis of these eleven students demonstrates that only one of the eleven had been on placement at Derriford Hospital (χ 2 , p = 0.006).Thirty-five (46%) of the students had examined a patient with a transplanted kidney but only thirty-three (43%) could accurately draw on a diagram the usual site of surgical incision that would be made on someone undergoing a left sided renal transplant. Interestingly, fourteen of the students that claimed to have examined a transplant recipient were unable to accurately draw the site of incision. Of the students that had examined a transplant recipient twenty-two had been on placement at one of the hospitals with transplant centres and thirteen had not (χ 2 , p = 0.128).Fifty students (66%) were aware that in addition to the use of organs from brain stem dead donors, kidneys could also be transplanted from living donors. Eighteen students (24%) could not name any additional sources of organs and seven (9%) thought that xenotransplantation, using porcine kidneys, is carried out in the UK. None of the students suggested non-heart beating donation.Nineteen students (25%) were unable to name a drug that might be taken by a patient with a renal transplant. Twenty-one students (28%) were able to suggest just one.Discussion This survey highlights both a low exposure to, and a lack of knowledge about, the field of renal transplantation amongst medical students. This is cause for concern as it has implications for the future recruitment of trainees to the speciality and, potentially, to the procurement of organs. Previous work has highlighted the multiple factors that deter surgical trainees from this speciality [ 5 ]. These include the on-call commitment, unpredictable workload and a lack of exposure to the speciality, at an early stage in training. Based on this information, calls have been made to increase the exposure of surgical trainees by the inclusion of transplantation within basic surgical training (BST) rotation programmes [ 5 ]. However, as there are only 23 surgical centres performing renal transplantation within the UK it is unlikely that all trainees would be exposed to the field. In order to gain exposure to the maximum number of doctors, early in their careers, targeting medical students may yield the best results. Indeed, a recent crisis meeting regarding recruitment to renal transplant surgery identified that early positive exposure to the field is vital, and should begin at the undergraduate level [ 6 ]. This survey highlights that the potential for the promotion of renal transplantation within the undergraduate course is currently relatively unexplored. The lack of knowledge regarding sources of organs commonly used within the UK is also of concern. In order to increase the number of kidneys available UK Transplant funds a number of non-heart beating programmes. Such initiatives can potentially increase the transplant rate by 20–40% [ 9 ]. Identifying all potential heart beating and non-heart beating donors is fundamental to providing a successful service, and reducing the gap between donors and patients on the waiting list. However, if future doctors are unaware of the existence of these programmes then such schemes are unlikely to reach their full potential. One of the limitations of this study is the selection bias from a 54% response rate. From talking to some of the students who did not complete the questionnaire it became apparent that those who had no experience or knowledge of the speciality were less likely to participate. This means that the results are probably over reporting the exposure to and knowledge of renal transplantation. A further limitation is that this work only represents the situation at one medical school. We believe that this situation is not unique to Bristol University and recommend that a national study be performed to assess the true extent of the situation. If transplantation rates are to be maximised and recruitment into the speciality improved, then ideally, all doctors should have some exposure to renal transplantation during the early stages of their career. Indeed a recent study has demonstrated that increased knowledge about organ donation is associated with higher levels of medical education, an increased likelihood of holding an organ donor card and feeling more comfortable in approaching relatives of potential organ donors [ 7 ]. Whilst it is realised that teaching time is of a premium at medical school this would be the ideal opportunity to promote transplantation. We believe that conventional methods such as ward based teaching, lectures and tutorials could be supplemented with a more multidisciplinary exposure. For example, involving students in patient education open days or the production of information leaflets/web pages could allow students to see from themselves the improvement in quality of life brought about by transplantation; Such learning experiences may prove more memorable for some students than those of the operating theatre.
Discussion
This survey highlights both a low exposure to, and a lack of knowledge about, the field of renal transplantation amongst medical students. This is cause for concern as it has implications for the future recruitment of trainees to the speciality and, potentially, to the procurement of organs.Previous work has highlighted the multiple factors that deter surgical trainees from this speciality [ 5 ]. These include the on-call commitment, unpredictable workload and a lack of exposure to the speciality, at an early stage in training. Based on this information, calls have been made to increase the exposure of surgical trainees by the inclusion of transplantation within basic surgical training (BST) rotation programmes [ 5 ]. However, as there are only 23 surgical centres performing renal transplantation within the UK it is unlikely that all trainees would be exposed to the field. In order to gain exposure to the maximum number of doctors, early in their careers, targeting medical students may yield the best results. Indeed, a recent crisis meeting regarding recruitment to renal transplant surgery identified that early positive exposure to the field is vital, and should begin at the undergraduate level [ 6 ]. This survey highlights that the potential for the promotion of renal transplantation within the undergraduate course is currently relatively unexplored.The lack of knowledge regarding sources of organs commonly used within the UK is also of concern. In order to increase the number of kidneys available UK Transplant funds a number of non-heart beating programmes. Such initiatives can potentially increase the transplant rate by 20–40% [ 9 ]. Identifying all potential heart beating and non-heart beating donors is fundamental to providing a successful service, and reducing the gap between donors and patients on the waiting list. However, if future doctors are unaware of the existence of these programmes then such schemes are unlikely to reach their full potential.One of the limitations of this study is the selection bias from a 54% response rate. From talking to some of the students who did not complete the questionnaire it became apparent that those who had no experience or knowledge of the speciality were less likely to participate. This means that the results are probably over reporting the exposure to and knowledge of renal transplantation. A further limitation is that this work only represents the situation at one medical school. We believe that this situation is not unique to Bristol University and recommend that a national study be performed to assess the true extent of the situation.If transplantation rates are to be maximised and recruitment into the speciality improved, then ideally, all doctors should have some exposure to renal transplantation during the early stages of their career. Indeed a recent study has demonstrated that increased knowledge about organ donation is associated with higher levels of medical education, an increased likelihood of holding an organ donor card and feeling more comfortable in approaching relatives of potential organ donors [ 7 ]. Whilst it is realised that teaching time is of a premium at medical school this would be the ideal opportunity to promote transplantation. We believe that conventional methods such as ward based teaching, lectures and tutorials could be supplemented with a more multidisciplinary exposure. For example, involving students in patient education open days or the production of information leaflets/web pages could allow students to see from themselves the improvement in quality of life brought about by transplantation; Such learning experiences may prove more memorable for some students than those of the operating theatre.Conclusions This survey, carried out at a single UK medical school, has highlighted a low level of exposure to, and a lack of knowledge about, renal transplantation amongst medical students. These worrying results may influence the outcomes of any measures put in place to improve the recruitment of surgeons and the procurement of organs. If the trends within these areas are to be reversed then greater emphasis should be placed upon the promotion of renal transplantation within the undergraduate curriculum.
Conclusions
This survey, carried out at a single UK medical school, has highlighted a low level of exposure to, and a lack of knowledge about, renal transplantation amongst medical students. These worrying results may influence the outcomes of any measures put in place to improve the recruitment of surgeons and the procurement of organs. If the trends within these areas are to be reversed then greater emphasis should be placed upon the promotion of renal transplantation within the undergraduate curriculum.Abbreviations UK  United Kingdom PRHO  Pre-registration house officer
Abbreviations
UK  United KingdomUKPRHO  Pre-registration house officerPRHOCompeting interests The author(s) declare that they have no competing interests.
Competing interests
The author(s) declare that they have no competing interests.Authors' contributions AGE designed the questionnaire, performed the study and was involved in the preparation of the manuscript. ARW and JDM were also involved in the design of the questionnaire and manuscript preparation.
Authors' contributions
AGE designed the questionnaire, performed the study and was involved in the preparation of the manuscript. ARW and JDM were also involved in the design of the questionnaire and manuscript preparation.


Electroconvulsive therapy (ECT) often results in a number of short- and long-time side effects including memory impairment for past and current events, which can last for several months after ECT treatment. It has been suggested that unilateral ECT (uECT) with electrodes placed over the non-dominant (typically right) hemisphere significantly reduces side effects, especially memory disturbances. It is important to note that cerebral dominance equates to speech dominance and avoiding this area of the brain also reduces speech dysfunction after ECT. Traditionally, the routine clinical determination of cerebral dominance has been through the assessment of hand, foot and eye dominance, which is an easy and inexpensive approach that, however, does not ensure accuracy. This review of literature on different methods and techniques for determination of cerebral dominance and provides evidence that functional transcranial Doppler sonography (fTCD) represents a valid and safe alternative to invasive techniques for identifying speech lateralisation. It can be concluded that fTCD, notwithstanding its costs, could be used as a standard procedure prior to uECT treatment to determine cerebral dominance, thereby further reducing cognitive side-effects of ECT and possibly making it more acceptable to both patients and clinicians.

Introduction Electroconvulsive therapy (ECT) is often regarded by the general public as a controversial procedure for the treatment of mental disorders. This is despite evidence of its safety and efficacy [ 1 ], and its benefit over anti-depressants in patients resistant to conventional medications and those with life threatening conditions such as catatonia and depressive stupor. The evidence suggests that in unipolar depression ECT has better efficacy when compared with older tricyclic antidepressants and monoamine oxidase inhibitors, as well as newer drugs such as paroxetine [ 2 ]. Notwithstanding the efficacy of ECT, its use is declining in some countries [ 3 ], while in a few others, including Italy – where ECT was first introduced in 1938 by Cerletti and Bini – it is prohibited. Aside from political reasons and public pressure, the declining trend in ECT use could be the result of the introduction of more effective antidepressants. A further possible explanation for the reduction in ECT use may relate to the concern over adverse effects of the procedure. There are a number of short-term side effects including headache, nausea and, sometimes, brief confusion. However, the main side effect of concern is memory impairment for past events (retrograde amnesia) and for current events (anterograde amnesia) that can last for several months after a course of ECT treatment. Some of these side effects are substantially reduced by advances in safety and the introduction of controlled-current ECT machines. The utilisation of muscle relaxants, anaesthetics and resuscitation equipment, and electroencephalographic monitoring during the application of ECT are considered now considered routine. In addition, ECT guidelines issued by the UK National Institute for Clinical Excellence [ 4 ] restrict the use of ECT only to patients with severe symptoms to which "an adequate trial of other treatment options has proven ineffective" (p. 5). The risk associated with ECT has also been reduced with the introduction of refined ECT procedures, such as "maintenance ECT" or "unilateral ECT" (uECT) [ 5 ]. It has been suggested that unilateral treatment significantly reduces side effects, especially memory disturbances [ 6 , 7 ]. Despite the well-documented efficacy of unilateral over bilateral ECT, current practice still favours bilateral treatments [ 8 , 9 ]. Unilateral treatment, for the majority of patients, entails that electrodes are placed over the non-dominant, right hemisphere. Given that memory impairment could be reduced by unilateral electrode placement and the fact that placement of electrodes to the dominant hemisphere may cause a greater disturbance in memory compared to non-dominant uECT, determination of cerebral dominance appears to be critical [ 10 ]. It is important to note that cerebral dominance here equates to speech dominance, including a lateralised capacity of the cortex to be the locus of language-specific memory traces [ 11 ]. Avoiding the stimulation of the speech area will therefore reduce speech dysfunction after ECT. Traditionally, the routine clinical determination of cerebral dominance has been through the assessment of hand, foot and eye dominance. It certainly is an easy and inexpensive approach, but it does not ensure accuracy.
Introduction
Electroconvulsive therapy (ECT) is often regarded by the general public as a controversial procedure for the treatment of mental disorders. This is despite evidence of its safety and efficacy [ 1 ], and its benefit over anti-depressants in patients resistant to conventional medications and those with life threatening conditions such as catatonia and depressive stupor. The evidence suggests that in unipolar depression ECT has better efficacy when compared with older tricyclic antidepressants and monoamine oxidase inhibitors, as well as newer drugs such as paroxetine [ 2 ]. Notwithstanding the efficacy of ECT, its use is declining in some countries [ 3 ], while in a few others, including Italy – where ECT was first introduced in 1938 by Cerletti and Bini – it is prohibited. Aside from political reasons and public pressure, the declining trend in ECT use could be the result of the introduction of more effective antidepressants.A further possible explanation for the reduction in ECT use may relate to the concern over adverse effects of the procedure. There are a number of short-term side effects including headache, nausea and, sometimes, brief confusion. However, the main side effect of concern is memory impairment for past events (retrograde amnesia) and for current events (anterograde amnesia) that can last for several months after a course of ECT treatment. Some of these side effects are substantially reduced by advances in safety and the introduction of controlled-current ECT machines. The utilisation of muscle relaxants, anaesthetics and resuscitation equipment, and electroencephalographic monitoring during the application of ECT are considered now considered routine. In addition, ECT guidelines issued by the UK National Institute for Clinical Excellence [ 4 ] restrict the use of ECT only to patients with severe symptoms to which "an adequate trial of other treatment options has proven ineffective" (p. 5). The risk associated with ECT has also been reduced with the introduction of refined ECT procedures, such as "maintenance ECT" or "unilateral ECT" (uECT) [ 5 ].It has been suggested that unilateral treatment significantly reduces side effects, especially memory disturbances [ 6 , 7 ]. Despite the well-documented efficacy of unilateral over bilateral ECT, current practice still favours bilateral treatments [ 8 , 9 ]. Unilateral treatment, for the majority of patients, entails that electrodes are placed over the non-dominant, right hemisphere. Given that memory impairment could be reduced by unilateral electrode placement and the fact that placement of electrodes to the dominant hemisphere may cause a greater disturbance in memory compared to non-dominant uECT, determination of cerebral dominance appears to be critical [ 10 ]. It is important to note that cerebral dominance here equates to speech dominance, including a lateralised capacity of the cortex to be the locus of language-specific memory traces [ 11 ]. Avoiding the stimulation of the speech area will therefore reduce speech dysfunction after ECT. Traditionally, the routine clinical determination of cerebral dominance has been through the assessment of hand, foot and eye dominance. It certainly is an easy and inexpensive approach, but it does not ensure accuracy.Unilateral ECT and cerebral dominance The practice of determining cerebral dominance from handedness appears to mirror Broca's view that a person's handedness is opposite to hemispheric language specialisation. This, however, is incorrect, since there is no "mirror-image" cortical language organisation in left-handers. Several attempts to improve cerebral dominance assessment by introducing additional clues such as handwriting posture (i.e. inverted or hooked style versus non-inverted) and familial sinistrality have not substantially improved the prediction as to determination of cerebral dominance [ 12 , 13 ]. For example, the use of hand writing posture to determine speech dominance has been shown to be completely invalid [ 14 - 16 ]. A great majority of left-handers have also an ipsilateral functional specialisation for language (i.e. left hemispheric, as in the majority of right-handers). Although right-handers are more clearly lateralised than left-handers in this regard, a certain proportion of right-handers have language localised in the right-hemisphere. This has been confirmed by various techniques, ranging from the old and invasive procedures such as the intracarotid sodium amytal test and ECT, to the new and more sophisticated techniques such as functional magnetic resonance imaging (fMRI) and functional transcranial Doppler sonography (fTCD). The pooling of empirical data from a number of studies [ 17 - 27 ] which used both old and new, non-invasive techniques to determine cerebral dominance for language is shown in Table  1 . Table 1 Percentages of right- and left-handers with speech localised predominantly in the left, right hemisphere, or bilaterally, according to different studies and techniques Study Right-handers Left-handers Left Bilateral Right Left Bilateral Right Milner, 1975* 96 0 4 70 15 15 Rossi & Rosadini, 1967* 99 1 0 40 10 50 Pratt & Warrington, 1972 # 99 0 1 - - - Warrington & Pratt, 1973 # - - - 70 7 23 Geffen et al., 1978 # 92 0 8 67 0 33 Geffen & Traub, 1979 ‡ 84 9 7 61 15 24 Springer et al. 1999 & 94 6 0 - - - Pujol et al. 1999 & 96 4 0 76 14 10 Szaflarski et al. 2002 & - - - 78 14 8 Hund-Georgiadis et al. 2002 & 94 0 6 47 12 41 Knecht et al. 2000 † - - 4 - - 27 * intracarotid sodium amytal test #  ECT ‡  dichotic listening test & fMRI †  fTCD From Table  1  one can see that if the hemisphere for uECT treatment were solely ascertained from handedness assessment, then a small proportion of right-handers and a much larger proportion of left-handers would have treatment administered to the dominant hemisphere. One could also see from it that about 3% of right-handers and 25% of left-handers have speech localised in the right hemisphere. This represents the error rate percentage in both groups if uECT was administered to all patients on the right side of the cranium. However, the overall error rate is lower since the incidence of left-handedness is low, and is likely to be in the range of 6.4% to 12.5% [ 28 ]. A strict application of the "mirror-image" cortical organisation (i.e. considering left-handers as right-hemisphere dominant and therefore performing left-sided uECT) is even more destructive, illogical, and would increase the error rate. For example, in the survey of the use of ECT by psychiatrists in New Zealand [ 9 ], 20% of respondents reported using uECT depending on handedness. Adverse effects caused by determining speech dominance on the basis of handedness would be lower if right-sided ECT was always administered, thus making handedness assessment unnecessary. Given the additional risk of uECT treatment on the dominant hemisphere, which is even more disruptive than bilateral ECT [ 29 ], correct identification of cerebral dominance appears to be crucial. The importance of identification of cerebral dominance prior to electrode placement has been highlighted by a number of authors [ 6 , 10 , 28 ], but routine ECT practice has remained unchanged.
Unilateral ECT and cerebral dominance
The practice of determining cerebral dominance from handedness appears to mirror Broca's view that a person's handedness is opposite to hemispheric language specialisation. This, however, is incorrect, since there is no "mirror-image" cortical language organisation in left-handers. Several attempts to improve cerebral dominance assessment by introducing additional clues such as handwriting posture (i.e. inverted or hooked style versus non-inverted) and familial sinistrality have not substantially improved the prediction as to determination of cerebral dominance [ 12 , 13 ]. For example, the use of hand writing posture to determine speech dominance has been shown to be completely invalid [ 14 - 16 ].A great majority of left-handers have also an ipsilateral functional specialisation for language (i.e. left hemispheric, as in the majority of right-handers). Although right-handers are more clearly lateralised than left-handers in this regard, a certain proportion of right-handers have language localised in the right-hemisphere. This has been confirmed by various techniques, ranging from the old and invasive procedures such as the intracarotid sodium amytal test and ECT, to the new and more sophisticated techniques such as functional magnetic resonance imaging (fMRI) and functional transcranial Doppler sonography (fTCD). The pooling of empirical data from a number of studies [ 17 - 27 ] which used both old and new, non-invasive techniques to determine cerebral dominance for language is shown in Table  1 .Percentages of right- and left-handers with speech localised predominantly in the left, right hemisphere, or bilaterally, according to different studies and techniques* intracarotid sodium amytal test#  ECT‡  dichotic listening test& fMRI†  fTCDFrom Table  1  one can see that if the hemisphere for uECT treatment were solely ascertained from handedness assessment, then a small proportion of right-handers and a much larger proportion of left-handers would have treatment administered to the dominant hemisphere. One could also see from it that about 3% of right-handers and 25% of left-handers have speech localised in the right hemisphere. This represents the error rate percentage in both groups if uECT was administered to all patients on the right side of the cranium. However, the overall error rate is lower since the incidence of left-handedness is low, and is likely to be in the range of 6.4% to 12.5% [ 28 ]. A strict application of the "mirror-image" cortical organisation (i.e. considering left-handers as right-hemisphere dominant and therefore performing left-sided uECT) is even more destructive, illogical, and would increase the error rate. For example, in the survey of the use of ECT by psychiatrists in New Zealand [ 9 ], 20% of respondents reported using uECT depending on handedness. Adverse effects caused by determining speech dominance on the basis of handedness would be lower if right-sided ECT was always administered, thus making handedness assessment unnecessary. Given the additional risk of uECT treatment on the dominant hemisphere, which is even more disruptive than bilateral ECT [ 29 ], correct identification of cerebral dominance appears to be crucial. The importance of identification of cerebral dominance prior to electrode placement has been highlighted by a number of authors [ 6 , 10 , 28 ], but routine ECT practice has remained unchanged.From intracarotid injection to transcranial sonography Until recently, an accurate determination of speech dominance prior to a course of ECT treatment was possible only through invasive procedures such as intracarotid sodium amytal test [ 30 ], also known as the Wada tests, and through the administration of ECT itself – the ECT Test [ 10 ]. Lateralisation of language capacity using the Wada test is based on the temporary anaesthesia of one half of the brain. The subject in the study receives sodium amytal – a short-acting anaesthetic – into (usually) the left carotid artery. This causes the left hemisphere to be temporarily rendered dysfunctional. As a result, if this were the patient's dominant hemisphere, the subject's language capacity – primarily speech production – is affected. Conversely, injecting sodium amytal into the right carotid artery leaves this language capacity intact. By using this technique it is possible to identify precisely which hemisphere hosts language, which is considered necessary for patients who are to go through neurosurgical procedures. Although accurate, the use of Wada procedure in a normal healthy population is generally considered as unsuitable. Using ECT for the determination of cerebral dominance is, as mentioned previously, associated with adverse effects and therefore may not be entirely appropriate, although Weiner [ 31 ] suggests giving left and right side ECT alternately followed by the administration of a simple verbal performance test and then continuing treatment with the side associated with the better result. The advent of sophisticated and non-invasive technologies during the 1980s and 1990s has enabled a non-invasive approach to the assessment of speech dominance. One of the most elegant, mobile, and cost effective methods for determining cerebral dominance for speech is functional transcranial Doppler sonography (fTCD). fTCD is increasingly used in both clinical and research settings and is a new and robust technique based on the same principles as fMRI. Subjects in studies using this method are asked to generate as many possible words within 5-second periods after a letter presented on the computer screen cues for word generation. Basically, fTCD measures cerebral blood flow velocity which corresponds to brain activity. The physical foundation for this technique is quite old and is based on the work of the Austrian mathematician and physicist, Christian Doppler (1803–1853), who discovered that the change in pitch results from a shift in the frequency of the sound waves. This means that the speed of a physical object (i.e. blood) can be estimated by measuring the rate of change of pitch. To complete the fTCD procedure, the additional sound produced through the arteries is required. Recently, it has been argued that fTCD can reliably replace the Wada procedure in patients undergoing brain surgery [ 32 ]. The validity of fTCD has been established by comparing fTCD with the Wada test, which is considered as the ultimate (gold standard) test of cerebral lateralisation for speech. Several independent studies [ 33 - 35 ] have found highly significant correlations between these two methods. A high agreement between fTCD and fMRI has also been identified [ 36 ] for the assessment of cerebral speech lateralisation.
From intracarotid injection to transcranial sonography
Until recently, an accurate determination of speech dominance prior to a course of ECT treatment was possible only through invasive procedures such as intracarotid sodium amytal test [ 30 ], also known as the Wada tests, and through the administration of ECT itself – the ECT Test [ 10 ]. Lateralisation of language capacity using the Wada test is based on the temporary anaesthesia of one half of the brain. The subject in the study receives sodium amytal – a short-acting anaesthetic – into (usually) the left carotid artery. This causes the left hemisphere to be temporarily rendered dysfunctional. As a result, if this were the patient's dominant hemisphere, the subject's language capacity – primarily speech production – is affected. Conversely, injecting sodium amytal into the right carotid artery leaves this language capacity intact. By using this technique it is possible to identify precisely which hemisphere hosts language, which is considered necessary for patients who are to go through neurosurgical procedures. Although accurate, the use of Wada procedure in a normal healthy population is generally considered as unsuitable. Using ECT for the determination of cerebral dominance is, as mentioned previously, associated with adverse effects and therefore may not be entirely appropriate, although Weiner [ 31 ] suggests giving left and right side ECT alternately followed by the administration of a simple verbal performance test and then continuing treatment with the side associated with the better result.The advent of sophisticated and non-invasive technologies during the 1980s and 1990s has enabled a non-invasive approach to the assessment of speech dominance. One of the most elegant, mobile, and cost effective methods for determining cerebral dominance for speech is functional transcranial Doppler sonography (fTCD). fTCD is increasingly used in both clinical and research settings and is a new and robust technique based on the same principles as fMRI. Subjects in studies using this method are asked to generate as many possible words within 5-second periods after a letter presented on the computer screen cues for word generation. Basically, fTCD measures cerebral blood flow velocity which corresponds to brain activity. The physical foundation for this technique is quite old and is based on the work of the Austrian mathematician and physicist, Christian Doppler (1803–1853), who discovered that the change in pitch results from a shift in the frequency of the sound waves. This means that the speed of a physical object (i.e. blood) can be estimated by measuring the rate of change of pitch. To complete the fTCD procedure, the additional sound produced through the arteries is required.Recently, it has been argued that fTCD can reliably replace the Wada procedure in patients undergoing brain surgery [ 32 ]. The validity of fTCD has been established by comparing fTCD with the Wada test, which is considered as the ultimate (gold standard) test of cerebral lateralisation for speech. Several independent studies [ 33 - 35 ] have found highly significant correlations between these two methods. A high agreement between fTCD and fMRI has also been identified [ 36 ] for the assessment of cerebral speech lateralisation.Conclusion This review of the literature on ECT and cerebral dominance provides evidence that fTCD represents a valid and safe alternative to invasive techniques for identifying speech lateralisation. It seems therefore, that fTCD, notwithstanding costs, could be used as a standard procedure prior to uECT treatment to determine cerebral dominance, thereby further reducing cognitive side-effects of ECT and possibly making it more acceptable to both patients and clinicians.
Conclusion
This review of the literature on ECT and cerebral dominance provides evidence that fTCD represents a valid and safe alternative to invasive techniques for identifying speech lateralisation. It seems therefore, that fTCD, notwithstanding costs, could be used as a standard procedure prior to uECT treatment to determine cerebral dominance, thereby further reducing cognitive side-effects of ECT and possibly making it more acceptable to both patients and clinicians.Competing interests none declared.
Competing interests
none declared.