COMPARISON OF THE SEMMES-WEINSTEIN MONOFILAMENTS WITH THE PRESSURE-SPECIFYING SENSORY DEVICE

Measuring human sensibility remains a challenge, with the primary limi tation being the instrumentation traditionally available. The Pressure -Specifying Sensory Device (PSD) permits quantitation of the human pre ssure perception threshold by means of transducers that couple two rou nded prongs to a personal computer. If just one prong is perceived in constant contact with the skin, the cutaneous pressure threshold is di rectly obtained, scaling along a continuum from .05 to 100 g/mm2 (read out on computer monitor). This measurement is analogous to that obtain ed with the series of Semmes-Weinstein monofilaments (SWM) (readout in logarithmic marking on nylon rod). The present study evaluated twenty normal volunteers and ten nerve-impaired patients with both the PSD a nd the SWM. There was a poor correlation between the measurement of fo rce (r = 0.2 1) and pressure (r = 0.29) obtained with the PSD and the SWM. This study reaffirms the value of measuring pressure perception t hreshold during the sensibility evaluation, while calling attention to selection of instrumentation for obtaining this measurement.