[Effect of aging on P300 in normal subjects].
The P300 component of the event-related brain potential (ERP) is generated when subjects discriminate stimulus events which differ from one another. There are many reports about the effect of age on P300 in clinically normal subjects. However, these subjects may include individuals with silent cerebral infarctions or abnormal periventricular hyperintensity (PVH) on MRI. In this study, we completely excluded such subjects using MRI and examined the effect of aging on P300. One hundred four neurologically normal subjects (mean age 58.6 years, 55 men, 49 women) who had no lesions or severe PVH on MRI were selected. An oddball stimulus paradigm was employed and ERPs were elicited by presenting a series of binaural 1000 (82%) and 2000Hz (18%) tones through headphones. Prolongation of P300 latency was significantly correlated with advancing age (p less than 0.001): P300 latency increased by approximately 1.7 msec per year of age, with a prominent increase after age 60. But there was no significant difference between males and females in P300 latency. The significant correlation between age and P300 amplitude was observed only at Pz (p less than 0.05). These results indicate that there is a gradual mental decline with aging in normal subjects without silent cerebral infarctions or PVH.
Yamashita
K
K
Third Division of Internal Medicine, Shimane Medical University, Izumo, Japan.
Kobayashi
S
S
Koide
H
H
Yamaguchi
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values