Effects of aging and sex on middle-latency somatosensory evoked potentials: normative data

Objectives: To investigate the exact relationship of middle-latency somatosensory evoked potential (SEP) components (in particular the third negative component N60) to age and sex in a normal population. Middle-latency SEPs are believed to show a considerable inter-individual variability and there is little published information on normative data of these components. Methods: Eighty-three healthy subjects aged 13–80 years were investigated using a standard SEP procedure. Results: Both latency and amplitude of N60 increased substantially with age. Least square polynomial regression analysis showed that a quadratic curve best described its relationship (r2=0.67 for the latency, r2=0.18 for the amplitude). Data did not differ significantly with reference to sex or side of stimulation. Conclusions: The use of polynomial regression analysis for the determination of the normal range of N60 latencies and amplitudes has to be highly recommended. It might improve the accuracy with which abnormal results are detected in studies investigating the value of middle-latency SEPs in various diseases.