Adaptation of postural responses during different standing perturbation conditions in individuals with incomplete spinal cord injury.
Incomplete spinal cord injury (ISCI) frequently disrupts afferent and efferent neural pathways underlying co-requisite voluntary and involuntary muscle activation required for functional standing and walking. To understand involuntary postural control mechanisms necessary for standing, we compared eight individuals with ISCI to eight controls with no impairment. The aim of this study was to investigate anticipatory and reactive balance responses in individuals with ISCI. The ability to adapt to changes in balance conditions was assessed by monitoring automatic postural responses (APRs) during a series of expected and unexpected changes in perturbation direction (backward translation versus toes-up rotation). Both groups were able to modulate appropriately within one or two trials following an unexpected change in condition. Onset times of anterior tibialis and medial gastrocnemius (MG) were significantly slower in the ISCI group during expected and unexpected conditions. These findings demonstrate that persons with mild to moderate lower extremity sensorimotor deficits are able to generate and adapt APRs to a rapid and unexpected contextual change during a simple standing balance task.
Thigpen
Mary T
MT
Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32608, United States. mthigpen@phhp.ufl.edu
Cauraugh
James
J
Creel
Gwen
G
Day
Kristin
K
Flynn
Sheryl
S
Fritz
Stacy
S
Frost
Shirley
S
Respess
Robert
R
Gardner-Smith
Portia
P
Brack
Mia
M
Behrman
Andrea
A
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*