Modality-Specific, Multitask Locomotor Deficits Persist Despite Good Recovery After a Traumatic Brain Injury  Bradford J. McFadyen, PhD, Jean-François Cantin, PhD, Bonnie Swaine, PhD, Guylaine Duchesneau, MPs, Julien Doyon, PhD, Denyse Dumas, PT, Philippe Fait, MSc  Archives of Physical Medicine and Rehabilitation  Volume 90, Issue 9, Pages 1596-1606 (September 2009) DOI: 10.1016/j.apmr.2009.03.010 Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 1 Experimental setup showing the walking path, obstacle placement, force plate used to trigger both cognitive tasks (arrow), and orientation of computer monitors presenting the visual Stroop task. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 2 Walking speeds (A, B) and intrasubject variability in walking speeds (C, D) during unobstructed and obstructed walking. Data are indicated for subjects with TBI (dark boxes) and control subjects (pale boxes) with no division of attention and with simultaneous visual and auditory Stroop tasks. The box plots indicate medians (thick horizontal bars), the 75th (top of box) percentile range, and 25th (bottom of box) percentile range, whereas I-bars indicate full ranges. Outliers (empty circles) represent values that were at least 1.5 times greater or less than the interquartile range. Significant differences (P≤.05) are shown within groups (thin solid line) and between groups (dashed line). Abbreviations: _A, auditory Stroop tasks; NO, unobstructed walking; O, obstructed walking; _V, visual Stroop tasks. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 3 Clearance margins for lead (A) and trail (B) limbs and intrasubject variability in clearance margins for the same limbs (C, D) during unobstructed and obstructed walking. Data are indicated for subjects with TBI (dark boxes) and control subjects (pale boxes) without any division of attention and with simultaneous visual and auditory Stroop tasks. The box plots indicate medians (thick horizontal bars), the 75th (top of box) percentile range, and the 25th (bottom of box) percentile range, whereas I-bars indicate full ranges. Outliers (empty circles) represent values that were at least 1.5 times greater or less than the interquartile range. Significant differences (P≤.05) are shown within groups (thin solid line) and between groups (dashed line). Abbreviations: _A, auditory Stroop tasks; NO, unobstructed walking; O, obstructed walking; _V, visual Stroop tasks. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 4 Response reaction times for stimulus 1 (A, B) and 2 (C, D) during unobstructed and obstructed walking. Data are indicated for subjects with TBI (dark boxes) and control subjects (pale boxes) with simultaneous visual and auditory Stroop tasks. The box plots indicate medians (thick horizontal bars), the 75th (top of box) percentile range, and the 25th (bottom of box) percentile range, whereas I-bars indicate full ranges. Outliers (empty circles) represent values that were at least 1.5 times greater or less than the interquartile range. Significant differences (P≤.05) are shown within groups (thin solid line) and between groups (dashed line). Abbreviations: _A, auditory Stroop tasks; NO, unobstructed walking; O, obstructed walking; _V, visual Stroop tasks. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 5 Intrasubject variability in response reaction times for stimulus 1 (A, B) and 2 (C, D) during unobstructed and obstructed walking. Data are indicated for subjects with TBI (dark boxes) and control subjects (pale boxes) with simultaneous visual and auditory Stroop tasks. The box plots indicate medians (thick horizontal bars), the 75th (top of box) percentile range, and the 25th (bottom of box) percentile range, whereas I-bars indicate full ranges. Outliers (empty circles) represent values that were at least 1.5 times greater or less than the interquartile range. Significant differences (P≤.05) are shown within groups (thin solid line) and between groups (dashed line). Abbreviations: _A, auditory Stroop tasks; NO, unobstructed walking; O, obstructed walking; _V, visual Stroop tasks. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions

Fig 6 Multitask costs (A, B) and intrasubject variability (C, D) for stimuli 1 and 2. Data are indicated for subjects with TBI (dark boxes) and control subjects (pale boxes) with simultaneous visual and auditory Stroop tasks. The box plots indicate medians (thick horizontal bars), the 75th (top of box) percentile range, and 25th (bottom of box) percentile range, whereas I-bars indicate full ranges. Outliers (empty circles) represent values that were at least 1.5 times greater or less than the interquartile range. Significant differences (P≤.05) are shown within groups (thin solid line) and between groups (dashed line). Abbreviations: _A, auditory Stroop tasks; _V, visual Stroop tasks. Archives of Physical Medicine and Rehabilitation 2009 90, 1596-1606DOI: (10.1016/j.apmr.2009.03.010) Copyright © 2009 American Congress of Rehabilitation Medicine Terms and Conditions