The influence of transcutaneous electrical nerve stimulation (tens) on hemiplegic spasticity and voluntary muscle power /

These studies investigated possible relief of spasticity in hemiparetic subjects by transcutaneous electrical nerve stimulation (TENS) and its underlying mechanisms. The first two studies quantified the disorders in reflex and voluntary motor functions and addressed the reproducibility of their measurement and their correlation with spasticity scores. Soleus stretch reflexes were enhanced and isometric voluntary contraction force was decreased linearly with increasing spasticity. The last two studies addressed the effects of single and repetitive TENS stimulation on spasticity, reflex and isometric voluntary contractions. Compared to placebo stimulation, single 45 min sessions of TENS prolonged H and stretch reflex latencies for up to 60 min following stimulation. Repetitive (15 daily, 60 min) applications significantly decreased spasticity scores, Hvib/Hctl ratios, stretch reflexes and co-contraction while improving dorsiflexion force. The improvement in spasticity and voluntary motor control may partly have been mediated by presynaptic inhibition and reduced hyperactive stretch reflexes thereby 'unmasking' descending control