OBJECTIVE: To investigate whether differences in visual evoked potential (VEP) latencies in a large sample of healthy subjects are influenced by different head size or sex or both. METHODS: Black-and-white pattern-reversal checkerboard VEPs at a frequency of 2c/deg. were recorded in a group of 54 normal subjects of both sexes (age 30.15+/-9.12 years). P100 latency was measured in all subjects and the data were analyzed in the whole sample and in a selected subgroup of subjects of both sexes with comparable head size. RESULTS: In the study group overall, the P100 latency was slightly shorter in females than males and this small difference reached only weak statistical significance (P<0.04) whereas head size differed significantly between sexes (females<males) (P<0.001). No difference was found in the P100 latency in the subgroup of the two sexes with a comparable range of head size. CONCLUSIONS: These findings suggest that VEP latency is relatively constant in a sample of healthy subjects. The slight sex difference in P100 latencies observed in a normal sample is mainly related to the slightly smaller average head size in females than in males. SIGNIFICANCE: Head size, not sex, should be considered for VEP latency normative studies.
OBJECTIVE: To investigate whether differences in visual evoked potential (VEP) latencies in a large sample of healthy subjects are influenced by different head size or sex or both. METHODS: Black-and-white pattern-reversal checkerboard VEPs at a frequency of 2c/deg. were recorded in a group of 54 normal subjects of both sexes (age 30.15+/-9.12 years). P100 latency was measured in all subjects and the data were analyzed in the whole sample and in a selected subgroup of subjects of both sexes with comparable head size. RESULTS: In the study group overall, the P100 latency was slightly shorter in females than males and this small difference reached only weak statistical significance (P<0.04) whereas head size differed significantly between sexes (females<males) (P<0.001). No difference was found in the P100 latency in the subgroup of the two sexes with a comparable range of head size. CONCLUSIONS: These findings suggest that VEP latency is relatively constant in a sample of healthy subjects. The slight sex difference in P100 latencies observed in a normal sample is mainly related to the slightly smaller average head size in females than in males. SIGNIFICANCE: Head size, not sex, should be considered for VEP latency normative studies.