Modality-specific, multitask locomotor deficits persist despite good recovery after a traumatic brain injury.

OBJECTIVE: To study the effects of sensory modality of simultaneous tasks during walking with and without obstacles after moderate to severe traumatic brain injury (TBI). DESIGN: Group comparison study. SETTING: Gait analysis laboratory within a postacute rehabilitation facility. PARTICIPANTS: Volunteer sample (N=18). Persons with moderate to severe TBI (n=11) (9 men, 3 women; age, 37.56+/-13.79 y) and a comparison group (n=7) of subjects without neurologic problems matched on average for body mass index and age (4 men, 3 women; age, 39.19+/-17.35 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Magnitudes and variability for walking speeds, foot clearance margins (ratio of foot clearance distance to obstacle height), and response reaction times (both direct and as a relative cost because of obstacle avoidance). RESULTS: The TBI group had well-recovered walking speeds and a general ability to avoid obstacles. However, these subjects did show lower trail limb toe clearances (P=.003) across all conditions. Response reaction times to the Stroop tasks were longer in general for the TBI group (P=.017), and this group showed significant increases in response reaction times for the visual modality within the more challenging obstacle avoidance task that was not observed for control subjects. A measure of multitask costs related to differences in response reaction times between obstructed and unobstructed trials also only showed increased attention costs for the visual over the auditory stimuli for the TBI group (P=.002). CONCLUSIONS: Mobility is a complex construct, and the present results provide preliminary findings that, even after good locomotor recovery, subjects with moderate to severe TBI show residual locomotor deficits in multitasking. Furthermore, our results suggest that sensory modality is important, and greater multitask costs occur during sensory competition (ie, visual interference).

Can measures of cognitive function predict locomotor behaviour in complex environments following a traumatic brain injury?

PRIMARY OBJECTIVE: To determine the relationships between clinical measures of executive function and attention, and laboratory measures of anticipatory locomotor adaptations with dual tasks following a TBI. METHODS AND PROCEDURES: Ten people with moderate or severe TBI were compared to 10 healthy subjects for neuropsychological measures in the clinic, as well as locomotor patterns and reading time in the laboratory for adapted Stroop tasks (Bar and Word) during unobstructed and obstructed walking. MAIN OUTCOMES AND RESULTS: As previously found 1 (Vallee M, McFadyen BJ, Swaine B, Doyon J, Cantin JF, Dumas D. Effects of environmental demands on locomotion after traumatic brain injury. Archives of Physical Medicine Rehabilitation 2006;87:806--813) during the locomotor activities, subjects with TBI walked slower, had higher clearance margins and took longer to read during the Stroop tasks than healthy subjects. In general, subjects with TBI also showed deficits in executive functions and attention. Significant relationships were specifically observed between scores on Trail Making B and clearance margins for subjects with TBI, but not for healthy subjects. Alternatively, significant relationships between clinical scores on Stroop and dual task Stroop reading times were obtained for healthy subjects but not for subjects with TBI. CONCLUSIONS: These results suggest that measures of executive functioning and attention may be associated to locomotor behaviour in complex environments following a moderate to severe TBI.

Effects of environmental demands on locomotion after traumatic brain injury.

OBJECTIVE: To determine the effects of increasingly demanding environments related to simultaneous visual tasks and physical obstructions on the locomotor ability of people with traumatic brain injury (TBI). DESIGN: Group comparison study. SETTING: Gait analysis laboratory within a postacute rehabilitation facility. PARTICIPANTS: Volunteer sample of 9 people (8 men, 1 woman; age, 39.3+/-13.0y) with moderate to severe TBI and a comparison group of 9 subjects without neurologic problems matched for age and sex (8 men, 1 woman; age, 39.7+/-12.3y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Reading times for the Stroop bar and Stroop word tasks, walking speeds, stride lengths, and obstacle clearance margin. RESULTS: The TBI group was slower than the control group in performing the Stroop bar task during sitting (P=.002), and while avoiding the narrow obstacle (P=.05), and in performing the Stroop word task while avoiding the wide obstacle (P=.019). Despite their relatively normal gait speeds on level ground, subjects with TBI walked more slowly than control subjects for the narrow (P=.024) and the wide (P=.019) obstacle conditions and for the most complex dual task (P=.042). Greater lead-limb clearance margins were observed for the TBI group than for control subjects for all conditions whereas no differences were found for the trail limb except at the far end of the wide obstacle. CONCLUSIONS: Despite their good recovery of locomotor function, with respect to normal level walking speeds and ability to avoid obstacles, subjects with moderate and severe TBI showed residual deficits in relation to greater difficulties in dealing with environments that challenge their locomotor and attentional abilities. The use of such naturally based dual tasks may help identify some of the environmental obstructions to social participation after TBI.

Residual effects of a traumatic brain injury on locomotor capacity: a first study of spatiotemporal patterns during unobstructed and obstructed walking.

OBJECTIVES: To understand the residual locomotor effects of a traumatic brain injury (TBI) on unobstructed and obstructed walking. PARTICIPANTS: Eight young, high-functioning adults with TBI and 4 healthy subjects. MAIN OUTCOME MEASURES: Spatiotemporal gait parameters and their relation to specific clinical measures of severity and locomotor and balance abilities. RESULTS: Subjects with TBI walked slower and showed a tendency for greater foot clearances in all conditions. Slower walking was due to decreased stride lengths and not cadence, while higher foot clearances were due to placing the trailing foot farther from the obstacle and increasing hip flexion angles during avoidance. CONCLUSIONS: The results suggest that this highly functional TBI population used increased caution. Measures of injury severity did not provide simple predictions of locomotor ability, but the one-legged stance test with eyes closed correlated to walking capacity.