Finger-thumb coupling contributes to exaggerated thumb flexion in stroke survivors
| Autor: | Joseph D. Towles, William Z. Rymer, Megan O. Conrad, Kristen M. Triandafilou, Heidi C. Fischer, Derek G. Kamper |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Reflex Stretch Volition musculoskeletal diseases medicine.medical_specialty Physiology Motor Activity Thumb Fingers Physical medicine and rehabilitation Isometric Contraction medicine Humans Spasticity Stroke survivor Muscle Skeletal Stroke Hand Strength Electromyography business.industry General Neuroscience Articles Middle Aged Flexor muscles medicine.disease Coactivation Paresis body regions Coupling (electronics) Hemiparesis medicine.anatomical_structure Torque medicine.symptom business |
| Zdroj: | Journal of Neurophysiology. 111:2665-2674 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.00413.2013 |
| Popis: | The purpose of this study was to investigate altered finger-thumb coupling in individuals with chronic hemiparesis poststroke. First, an external device stretched finger flexor muscles by passively rotating the metacarpophalangeal (MCP) joints. Subjects then performed isometric finger or thumb force generation. Forces/torques and electromyographic signals were recorded for both the thumb and finger muscles. Stroke survivors with moderate ( n = 9) and severe ( n = 9) chronic hand impairment participated, along with neurologically intact individuals ( n = 9). Stroke survivors exhibited strong interactions between finger and thumb flexors. The stretch reflex evoked by stretch of the finger flexors of stroke survivors led to heteronymous reflex activity in the thumb, while attempts to produce isolated voluntary finger MCP flexion torque/thumb flexion force led to increased and undesired thumb force/finger MCP torque production poststroke with a striking asymmetry between voluntary flexion and extension. Coherence between the long finger and thumb flexors estimated using intermuscular electromyographic correlations, however, was small. Coactivation of thumb and finger flexor muscles was common in stroke survivors, whether activation was evoked by passive stretch or voluntary activation. The coupling appears to arise from subcortical or spinal sources. Flexor coupling between the thumb and fingers seems to contribute to undesired thumb flexor activity after stroke and may impact rehabilitation outcomes. |
| Databáze: | OpenAIRE |
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