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

目的：对患者进行随访2.6年的神经生理和心理生理检查。方法：每年对75例健康老年人进行事件相关电位（ERP）和定量背景脑电图（EEG）、迷你精神状态检查（MMSE）、连续表现测试（CPT）和选择性注意测试。(KN-VST)。同时进行精神病学访谈、体格检查、血尿检查和脑部计算机断层扫描，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：在2.6年的时间里，几乎所有区域的P300潜伏期都延长了10 m秒。以前的作者报道，使用横断面方法，P300潜伏期的延长伴随着衰老，每年延长1-2 m秒。定量脑电图分析显示，几乎所有区域的快波显著增加，中心区域的慢波（慢θ波；4.0-6.0 Hz）显著减少，几乎所有区域的α波（中波段α波；9.0-11.5 Hz）显著减少。本研究发现，反映老年脑功能衰退的慢波增加和快波减少在70岁出头的健康老年人中并不存在。在CPT中，计算信号检测灵敏度指标d'值。在2.6年期间d'不变或增加的组中，P300潜伏期没有显著变化。相比之下，在d'减少的组中，观察到P300潜伏期明显延长。

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.