Bilateral synergy as an index of force coordination in chronic stroke
- 329 Downloads
Dysfunction in bilateral coordination post-stroke is responsible for impaired bilateral movements. This study examined bilateral synergies using the uncontrolled manifold (UCM) approach while individuals in a chronic stage after stroke executed bilateral isometric force control at three submaximal force levels. Nine patients with stroke and nine age-matched healthy controls performed 24 trials of wrist and fingers extension at 5, 25, and 50% of MVC. The UCM findings revealed: (a) decreased bilateral synergies in patients with stroke as compared to controls at 50% of MVC and (b) reduced good variability and increased bad variability components in patients with stroke at 50% of MVC. Moreover, correlation analyses across both groups showed that a reduction of bilateral synergies was related to increased force error at 50% of MVC and an inconsistent force ratio between the two hands across multiple trials correlated with increased good and bad variability at 5% of MVC. Current findings indicate that quantifying bilateral synergies may provide meaningful profiles for estimating impairments as well as improvements of cooperative behaviors between two hands post-stroke.
KeywordsStroke Bilateral force control Uncontrolled manifold Bilateral synergies Coordination Upper extremity
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interest.
- Benjamini Y, Hochberg Y (1995) Controlling the false discovery rate—a practical and powerful approach to multiple testing. J R Stat Soc B Met 57:289–300Google Scholar
- Kang N, Cauraugh JH (2014a) Bimanual force variability and chronic stroke: asymmetrical hand control. PLos One 9:e101817Google Scholar
- Kelso JAS (1984) Phase transitions and critical behavior in human bimanual coordination. Am J Physiol 246:1000–1004Google Scholar
- Sainburg R, Good D, Przybyla A (2013) Bilateral synergy: a framework for post-stroke rehabilitation. J Neurol Transl Neurosci 1:1025Google Scholar