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

目的：对神经生理学和心理生理学检查进行2.6年的随访研究。方法：每年对75名健康老年人进行事件相关电位(ERP)、定量背景脑电、简易精神状态检查(MMSE)、连续操作测验(CPT)、选择注意测验。(KN-VST)。同时进行精神访视、体格检查、血尿检查及脑部CT检查，排除合并或既往中枢神经系统疾病，即可影响中枢神经系统的躯体疾病。结果：在2.6年中，几乎所有区域的P300潜伏期都延长了10ms。前人用横断法研究发现，随着年龄的增长，P300潜伏期每年延长1-2毫秒。定量脑电分析显示，几乎所有区域的快波显著增加，慢波(较慢的theta；4.0-6.0赫兹)显著减少，几乎所有区域的阿尔法波(中频段阿尔法；9.0-11.5赫兹)显著减少。本研究表明，在70年代初的健康老年人中，没有发现反映老年脑功能下降的慢波增加和快波减少。在CPT中，计算信号检测灵敏度指数d‘值。在2.6年中表现出d‘不变或增加的组中，P300潜伏期没有显著变化。相反，在d‘减少组，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.