Facilitation of the maximum voluntary contraction in hemiplegia by concomitant cutaneous stimulation

The effects of rapid brushing on the maximum voluntary contraction (MVC) and tonic vibratory reflex (TVR) of various muscles requiring facilitation (quadriceps, biceps femoris and tibialis anterior) were studied in two samples of hemiplegics. Brushing was studied under experimental and placebo conditions. In the first experiment, brushing produced significant facilitation of MVC and TVR in the quadriceps, replicating the findings of Spicer and Matyas (1980) and Matyas and Spicer (1980). However, the effect of the TVR failed to predict the gain in MVC that resulted from brushing. In the second sample of hemiplegics, brushing produced significant facilitation of the MVC and TVR in the biceps femoris but not in the tibialis anterior. The results for biceps femoris confirmed the results obtained with quadriceps. The failure to replicate this effect with tibialis anterior may have resulted from problems with the application of the stimulus to the relevant dermatome. Further exploration of the effect of cutaneous stimulation relating to this muscle is required to resolve this issue. The results of this experiment, with its replication of the facilitatory effect of brushing on TVR and MVC in two muscle groups, suggest that investigations of the effect of cutaneous stimulation on the acquisition and retention of voluntary movement should now take place.