A FOLLOW-UP STUDY ON NEUROPHYSIOLOGICAL FUNCTIONs OF THE NORMAI ELDERLY PEOPLE USING QUANTITATIVE EEG AND EVENT RELATED POTENTIALS

目的：对神经生理和心理生理检查进行2.6年的随访研究。研究方法：对75例健康老年人进行了事件相关电位（ERP）、定量背景脑电图（EEG）、简易精神状态检查（MMSE）、持续操作测验（CPT）和选择性注意测验。（KN-VST）。还进行了精神病学访谈、体格检查、血液和尿液检查以及脑计算机断层扫描，以排除并发或既往中枢神经系统疾病、可能影响中枢神经系统的身体疾病。结果：P300潜伏期在2.6年间延长了10毫秒。以往作者用横断面方法报道了P300潜伏期随年龄增长每年延长1-2毫秒。定量EEG分析显示几乎所有区域的快波显著增加，主要在中央区的慢波（较慢的θ波; 4.0-6.0 Hz）显著减少，几乎所有区域的α波（中频α波; 9.0-11.5 Hz）显著减少。本研究表明，反映老年脑功能衰退的慢波增加和快波减少，在70年代初的健康老年人中没有发现。在CPT中，计算d'值，即信号检测灵敏度的指数。在2.6年内d'不变或增加的组中，P300潜伏期没有显著变化。相反，在显示d '降低的组中，观察到P300潜伏期显著延长。

Objective : We made a 2.6-year follow-up study of neurophysiological and psychophysiological examination. Methods : Seventy-five healthy elderly people were examined every year with eventrelated potentials (ERP) and quantitative background EEG, mini mental state examination (MMSE), continuous performance test (CPT), and selective attention test. (KN-VST). The psychiatric interview, physical examination, blood and urine examination and brain computed tomography were also performed in order to exclude concurrent or past central nervous system disease, physical illness that could affect central nervous system. Results : The P300 latency showed an elongation of 10 m sec during 2.6 years in almost all areas. The previous authors reported that an elongation of P300 latency accompanied with aging was 1-2 m sec per year using cross-sectional method. Quantitative EEG analysis showed a significant increase in fast waves in almost all areas, a significant decrease in slow waves (slower theta ; 4.0-6.0 Hz) predominantly in the central area and a significant decrease in alpha waves (medium-band alpha ; 9.0-11.5 Hz) in almost all areas. The present study revealed that the increase in slow waves and the decrease in fast waves reflecting the decline of brain functions in the old age were not found in early seventies in healthy elderly people. In CPT, d' values, an index of signal detection sensitivity, were calculated. In the group showing either unchanged or increased d' during 2.6 years, P300 latency did not change significantly. In contrast, in the group showing decreased d', significant elongation of P300 latency was observed.