EARLY MODIFICATION OF STRETCH REFLEX IN PARKINSONS-DISEASE

We stretched quadriceps femoris in healthy subjects and in patients wi th a recent diagnosis of PD in order to assess whether modifications o f the long-latency component of the stretch reflex is an early event i n the course of Parkinson's disease (PD). We found a modified mechanic al and electromyographic (EMG) behavior in stretching relaxed muscles of patients while voluntary activation greatly reduced differences bet ween normal and Parkinsonian subjects, suggesting that a lower thresho ld of the response is an early sign in PD.