Relation of nonverbal intelligence assessed by Cattell's Culture Fair Intelligence Test to latencies of the somatosensory evoked potentials elicited by stimulation of the posterior tibial nerves in right-handed male and female subjects.

Abstract

The association of nonverbal intelligence (NVI) with latencies of the somatosensory evoked potentials from the right and left posterior tibial nerves (PTNs) was studied in right-handed male and female subjects without familial sinistrality (FS-). There was a significant negative linear correlation between N49-P39 interpeak latencies from the right and left PTNs in females and a significant positive linear correlation between these parameters in males. There was no significant correlation between P58-N49 interpeak latencies and NVI in females, but a significant negative linear correlation in males. The N76-P58 interpeak latencies were found to be positively linearly related to NVI only in females; there was no correlation between these parameters in males. There was no significant correlation between IQ and side differences in SEP latencies in females. The right minus left P39 latencies from the right and left PTN were found to be negatively linearly related to IQ in males. In females with nearly equal heights, latencies of N49 waves were found to be negatively linearly related to IQ. In males with nearly equal heights, only P39 and P58 waves from the right PTN were found to be negatively linearly related to IQ. These results did not support the hypothesis of speed of information processing by the brain in behavioral intelligence. An asymmetrical organization of the male brain seems to be disadvantageous for nonverbal intelligence; the female brain appeared to be independent of the degree of asymmetrical organization of the brain in this respect.