Brain stem auditory, pattern-reversal visual, and short-latency somatosensory evoked potentials: latencies in relation to age, sex, and brain and body size

To determine standards of normality for auditory, somatosensory and visual evoked potentials commonly used in the assessment of neurological disease, 8 AEP, 1 VEP and 12 SEP components were recorded to stimulation of left and right ears, eyes, and median nerves in 286 normal subjects ranging in age from 4 to 95 years. Peak and interpeak latencies, and left-right differences in latency, were analyzed as a function of age, sex, and estimates of brain and body size. Major features of the results were: (1) Peak latencies of all components showed statistically significant increases in latency with age except that VEP P100 latency decreased significantly between 4 and 19 years and did not change between 20 and 59 years. (2) In adults the peak latencies of all components were significantly later in males than in females. For AEPs and VEPs these differences were explained by sex differences in brain size, and for adult SEPs were explained by sex differences in arm and shoulder dimensions. No significant sex differences in VEP and SEP latencies were seen in children. (3) Most interpeak latencies showed significant differences in relation to age or sex. (4) Age and sex are useful predictors of latency for nearly all peak and interpeak latencies; in addition, height is a useful predictor of SEP peak latencies. (5) Left-right latency differences showed little age-related, and no sex-related, change. The interlaboratory use of these or other normative data was discussed. It was concluded that these AEP and SEP norms can probably be used in other laboratories if stimulating and recording conditions are similar. However, VEP results are difficult to transfer due to the poorly understood effects of variation in stimulus conditions. Some issues regarding the optimal characterization of norms were also discussed.