University of Hertfordshire

By the same authors

Documents

  • Ulrike Hammerbeck
  • Nada Yousif
  • Damon Hoad
  • Richard Greenwood
  • Jörn Diedrichsen
  • John C Rothwell
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Original languageEnglish
Pages (from-to)499-508
Number of pages10
JournalNeurorehabilitation and Neural Repair
Volume31
Issue6
Early online date1 Feb 2017
DOIs
Publication statusPublished - 1 Jun 2017

Abstract

BACKGROUND: Recovery from stroke is often said to have "plateaued" after 6 to 12 months. Yet training can still improve performance even in the chronic phase. Here we investigate the biomechanics of accuracy improvements during a reaching task and test whether they are affected by the speed at which movements are practiced.

METHOD: We trained 36 chronic stroke survivors (57.5 years, SD ± 11.5; 10 females) over 4 consecutive days to improve endpoint accuracy in an arm-reaching task (420 repetitions/day). Half of the group trained using fast movements and the other half slow movements. The trunk was constrained allowing only shoulder and elbow movement for task performance.

RESULTS: Before training, movements were variable, tended to undershoot the target, and terminated in contralateral workspace (flexion bias). Both groups improved movement accuracy by reducing trial-to-trial variability; however, change in endpoint bias (systematic error) was not significant. Improvements were greatest at the trained movement speed and generalized to other speeds in the fast training group. Small but significant improvements were observed in clinical measures in the fast training group.

CONCLUSIONS: The reduction in trial-to-trial variability without an alteration to endpoint bias suggests that improvements are achieved by better control over motor commands within the existing repertoire. Thus, 4 days' training allows stroke survivors to improve movements that they can already make. Whether new movement patterns can be acquired in the chronic phase will need to be tested in longer term studies. We recommend that training needs to be performed at slow and fast movement speeds to enhance generalization.

Notes

The final, definitive version of this paper has been published in Neurorehabilitation and Neural Repair, Vol. 31 (6), first published online February 2017, DOI: https://doi.org/10.1177/1545968317693112. Published by SAGE Publishing, All rights reserved.

ID: 11842025