Author/Editor		Prevec, TS; Berić, A
Title		Measurement of light touch perception thresold by contingent negative variation
Type		članek
Source		Exp Brain Res
Vol. and No.		Letnik 84
Publication year		1991
Volume		str. 643-8
Language		eng
Abstract		An objective method developed to measure the threshold of light touch perception using contingent negative variation (CNV) is described. The light touch stimulus was a slight indentation of the skin produced through a displacement controlled stimulating probe (tip diameter of 2 mm). It was applied as the conditioning (Sl) stimulus of the classical CNV paradigm of Sl, S2, and R. To increase the CNV amplitude, the S2 stimulus was either a red or a yellow LED. The subjects were required to respond to only one of two by pressing a button. When the light touch stimulus was perceived, the CNV was recorded in all 19 healthy adult volunteers. In 14 of them, a systematic determination ofthe threshold ofthe ball ofthe thumb and index finger, thenar, hypothenar, face, shoulder, anterior thigh, foot dorsum and great toe ball, have been done. The thresholds of the light touch perception as defined by objective CNV measurement are very close to the results uf the subjective psychophysiological determinations in normals. The amplitude of the averaged CNV (12 responses) started to decrease when stimulus intensity was reduced to the point that the subjects were able to perceive only a fraction of the presented touch stimuli. We believe, therefore, that the objective CNV determination of the light touch perception threshold is precise and sensitive enough to be used in research as well as in clinical applications.
Descriptors		CONTINGENT NEGATIVE VARIATION SENSORY THRESHOLDS TOUCH ADULT ELECTRODES FACE HAND LEG MIDDLE AGE REACTION TIME SHOULDER SKIN