Evoked Potential Tests of Augmenting-Reducing.

Two evoked potential tests of augmenting-reducing, using flash and sine wave modulated light stimuli, were administered to 23 normal Ss to determine: a) generalizability between tests; b) short-term reliability; c) influence of electrooculographic (EOG) activity; d) relationships between perceptual discrimination of stimuli and evoked response measurements; e) correlation between evoked responses, extraversion and neuroticism (Eysenck Personality Inventory). Four months later 11 Ss were retested before and after pilocarpine fixation of the pupil in miosis, to assess long-term reliability and pupillary factors. Although mean amplitudes of sine and flash responses were significantly positively correlated, correlations between linear slope measures of their intensity-response functions were low. Both short- and long-term reliability were high for mean amplitudes, but relatively low for most slope measures. Ocular factors, as reflected in EOG and changes with pupillary miosis, appeared to exert relatively little influence on the evoked potential measures of augmenting-reducing. Subjective perceptual discrimination performance was not correlated with evoked potential measures. Extraversion was correlated with some evoked response augmenting indicators; neuroticism yielded inconsistent results. Generally, results varied with lead placement. [ABSTRACT FROM AUTHOR]