The sensitivity of the sole of the foot in patients with Morbus Parkinson.

The sensory input of the foot has an important influence on balance. In patients with Morbus Parkinson (PD-patients) balance control is often impaired. Therefore, the aim of this study was to quantify the sensitivity of the plantar foot in PD-patients. Five sites of the plantar foot were examined in 24 PD-patients and in 20 controls using Semmes-Weinstein Monofilaments for touch pressure and a vibration-exciter (30 Hz) for vibration. The results show significantly higher thresholds in PD-patients. For each tested location (except the heel) the thresholds are at least twice as high as in controls. Moreover, this study proved the correlation between motor and somatosensory systems: the stronger the motor deficiencies in PD-patients (Unified Parkinson's Disease Rating System score) the higher the sensitivity thresholds for vibration. In conclusion, reduced sensitivity of the plantar foot may contribute to impaired balance control.