ASSESSMENT OF SPASTICITY IN HEMIPLEGIC CEREBRAL-PALSY .1. PROXIMAL LOWER-LIMB REFLEX EXCITABILITY

The quadriceps and hamstring muscles of 13 children with hemiplegic ce rebral palsy were studied using ramp and sinusoidal stretches at three different muscle lengths. Overall, the hamstring muscles showed great er velocity sensitivity than the quadriceps, with the hamstrings havin g the lowest reflex velocity and frequency thresholds close to maximum knee extension. At this position, the hemiparetic hamstrings alone sh owed a weakly significant reduced reflex frequency threshold compared with non-paretic muscles. For all other muscle lengths, non-paretic an d hemiparetic muscles displayed similar reflex thresholds when subject ed to sudden, discontinuous or repetitive rhythmical, sinusoidal stret ches. The number of muscles for which a reflex threshold could be esta blished declined progressively as the angle at the knee joint approach ed 900 of flexion. Muscles for which no reflex threshold could be demo nstrated had similar velocities and frequencies of stretch as those in which a reflex was obtained.