Preprogrammed reactions in individuals with Down syndrome: The effects of instruction and predictability of the perturbation

Mark Latash, G. L. Almeida, D. M. Corcos

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Preprogrammed reactions to unexpected loadings and unloadings of an elbow joint resisting an extending bias load were studied in subjects with Down syndrome. The subjects were instructed to either 'let go' or 'return back as fast as possible.' Both predictable and unpredictable perturbation directions were used. Integrated electromyograms of the two elbow flexors and two elbow extensors were used to characterize the preprogrammed reactions. All the subjects were able to modulate their preprogrammed reactions in response to a change in the instruction. They were also able to grade the preprogrammed responses corresponding to the magnitude of the perturbation. Two basic patterns of modulation were observed, 'reciprocal' and 'coactivation.' There were no effects of the predictability of the perturbation direction. Reconstructed joint compliant characteristics suggested an unchanged gain in the arc of the tonic stretch reflex. We propose that there are no abnormalities in the preprogrammed reactions of some individuals with Down syndrome. The apparent 'clumsiness' of individuals with Down syndrome in a changing environment is assumed to reflect an adaptation to their impaired decision-making ability. The high variability of motor performance in subjects with Down syndrome may result from mixing different strategies for solving motor tasks.

Original languageEnglish (US)
Pages (from-to)391-399
Number of pages9
JournalArchives of Physical Medicine and Rehabilitation
Volume74
Issue number4
StatePublished - Jan 1 1993

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Down Syndrome
Elbow
Stretch Reflex
Elbow Joint
Aptitude
Electromyography
Decision Making
Joints
Direction compound

All Science Journal Classification (ASJC) codes

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation

Cite this

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Preprogrammed reactions in individuals with Down syndrome : The effects of instruction and predictability of the perturbation. / Latash, Mark; Almeida, G. L.; Corcos, D. M.

In: Archives of Physical Medicine and Rehabilitation, Vol. 74, No. 4, 01.01.1993, p. 391-399.

Research output: Contribution to journalArticle

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