Directional sensibility for quantification of tactile dysfunction.

Examination of tactile directional sensibility, i.e., the ability to tell the direction of an object's motion across the skin, has been recommended by several authors for examination of patients with somatosensory disorders. Recent findings about the physiological mechanisms underlying directional sensibility suggested possibilities to further improve the test. In the present investigation a test was constructed that allowed a semiquantification of the directional sensibility of six body areas within 20 min. Normal values were obtained by testing healthy subjects (n = 40), and the normal values were compared to those obtained in a group of patients with tactile symptoms (n = 20). Ten of the patients had abnormal sensory conduction in one or several nerves, and they also had abnormal directional sensibility. Hence, examination of directional sensibility, according to the present protocol, provides a semiquantitative test that appears to be as sensitive as electrophysiological measurement of conduction in detecting dysfunction in tactile nerves.