Adapting human postural reflexes following localized cerebrovascular lesion

Analysis of bilateral long latency responses

Richard P. Di Fabio*, Mary Beth Badke, Pamela W. Duncan

*Corresponding author for this work

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

The symmetry and adaptability of long latency stretch responses was studied in a group of 4 adult hemiplegics and 5 normals of similar age. Subjects stood on a moveable platform which directly rotated the ankles unexpectedly during a series of horizontal anterioposterior (AP) translations. When the platform was rotated toes-up, long latency discharge of gastrocnemius and hamstring muscles enhanced loss of balance by pulling the body backwards. Toes-down platform rotation elicited a reflex response from tibialis anterior and quadriceps which inappropriately pulled the body forward. Attenuation of these long latency responses was necessary to minimize functional destabilization. Normal and stroke subjects demonstrated appropriate suppression of long latency responses, but the magnitude of attenuation was not uniform in hemiplegics. Adaptation was decreased in the proximal synergists compared to normal. Latency of muscle activation in the paretic limb was prolonged, and a preference for initial non-paretic limb activation was evident. Both lower extremities in hemiplegics showed a disruption of timing between distal and proximal synergists. These results suggest that stroke victims retain or recover the ability to modulate stretch reflex activity for balance. Temporal and spatial responses asymmetrics surface as critical factors underlying disequilibrium associated with localized cerebrovascular lesion.

Original languageEnglish
Pages (from-to)257-264
Number of pages8
JournalBrain Research
Volume363
Issue number2
DOIs
Publication statusPublished - 22 Jan 1986
Externally publishedYes

Keywords

  • balance
  • electromyogram (EMG)
  • posture
  • reflex
  • stroke

Fingerprint Dive into the research topics of 'Adapting human postural reflexes following localized cerebrovascular lesion: Analysis of bilateral long latency responses'. Together they form a unique fingerprint.

  • Cite this