A new approach to quantifying the EEG during walking: Initial evidence of gait related potentials and their changes with aging and dual tasking.
BACKGROUND
The electroencephalogram (EEG) can be a useful tool to investigate the neurophysiology of gait during walking. Our aims were to develop an approach that identify and quantify event related potentials (ERPs) during a gait cycle and to examine the effects of aging and dual tasking on these gait related potentials (GRPs).


METHODS
10 young and 10 older adults walked on a treadmill while wearing a wireless 20-channels EEG and accelerometers on the ankles. Each heel strike extracted from the accelerometers was used as an event to which the electrical brain activity pattern was locked. The subjects performed usual and dual task walking that included an auditory oddball task. GRPs amplitude and latency were computed, and a new measure referred to as Amplitude Pattern Consistency (APC) was developed to quantify the consistency of these GRP amplitudes within a gait cycle. The results were compared between and within groups using linear mixed model analysis.


RESULTS
The electrical pattern during a gait cycle consisted of two main positive GRPs. Differences in these GRPs between young and older adults were observed in Pz and Cz. In Pz, older adults had higher GRPs amplitude (p = 0.006, p = 0.010), and in Cz lower APC (p = 0.025). Alterations were also observed between the walking tasks. Both groups showed shorter latency during oddball walking compared to usual walking in Cz (p = 0.040). In addition, the APC in Cz was correlated with gait speed (r = 0.599, p = 0.011) in all subjects and with stride time variability in the older adults (r = -0.703, p = 0.023).


CONCLUSIONS
This study is the first to define specific gait related potentials within a gait cycle using novel methods for quantifying waveforms. Our findings show the potential of this approach to be applied broadly to study the EEG during gait in a variety of contexts. The observed changes in GRPs with aging and walking task and the relationship between GRPs and gait may suggest the neurophysiologic foundation for studying walking and for developing new approaches for improving gait.
['Maidan|I|I|', 'Patashov|D|D|', 'Shustak|S|S|', 'Fahoum|F|F|', 'Gazit|E|E|', 'Shapiro|B|B|', 'Levy|A|A|', 'Sosnik|R|R|', 'Giladi|N|N|', 'Hausdorff|J M|JM|', 'Mirelman|A|A|']
D061725:Accelerometry D000328:Adult D000368:Aged D000375:Aging D004569:Electroencephalography D005071:Evoked Potentials D005080:Exercise Test D005260:Female D005684:Gait D006801:Humans D008297:Male D008875:Middle Aged D000073456:Multitasking Behavior D011930:Reaction Time D016138:Walking
EEG Dual task Gait cycle Gait related potentials (GRP)