The later part of high-frequency oscillations in human somatosensory evoked potentials is enhanced in aged subjects.
High-frequency oscillations (HFOs) in the range of 300-900 Hz have been shown to occur simultaneously with the primary response (N20) of the human somatosensory cortex following median nerve stimulation. We studied the effects of aging on somatosensory evoked HFOs. Somatosensory evoked potentials (SEPs) were recorded with a filter set at 10-2000 Hz following right median nerve stimulation in 15 normal young subjects and 15 normal aged subjects. The HFOs were obtained by digitally filtering the wide-band SEPs (10-2000 Hz) using a band-pass of 300-900 Hz. In the aged subjects, the number of negative peaks, amplitudes, duration and area of the HFOs between N20 peak and HFO endpoint were significantly larger than those of young subjects. However, those between N20 onset and N20 peak did not differ between the groups. These results suggest that the later part of HFOs is associated with aging.
Nakano
S
S
Health Care Division, Yanagi-cho Works, Toshiba Corporation, Kawasaki, Japan. shuji.nakano@toshiba.co.jp
Hashimoto
I
I
D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged