Contractures and involuntary muscle overactivity in severe brain injury

Abstract

Primary objective: The aim of the present study was to evaluate the association of contractures with an increase or reduction of non-spastic muscle overactivity due to severe cerebral damage.

Methods and procedures: Forty-five patients with tetraparesis after severe cerebral damage were investigated. Three groups were defined based on the presence of spasticity (revealed as resistance to passive stretch (= hypertonia)), and the presence of contracture of the relevant knee joint: Group_s(17 patients with hypertonia without contracture), Group_s+c(20 patients with hypertonia and contracture), and Group_c(eight patients without hypertonia and with contracture). In all groups spontaneous involuntary muscle activity was assessed continuously over a 12-hour period through isometric measurement of knee joint flexion torque. A mathematical algorithm differentiated an hourly muscle activity spectrum (PI_h). The frequency of peaks (peaks_h) from the activity spectrum was determined.

Main outcomes and results: We revealed that Group_shad higher PI_hand more frequent peaks_hcompared with Group_s+cand Group_c(p < 0.05). Group_chad comparable PI_hand peaks_hcompared with Group_s+c(p > 0.05).

Conclusion: The presence of contractures was associated with lower involuntary muscle overactivity in terms of lower PI_hand less frequent peaks_h, indicating that contractures may be associated with reduced non-spastic positive features of the upper motor neurone syndrome in patients with severe brain damage.

• Spasticity
• muscle overactivity
• upper motor neurone syndrome
• muscle contracture