Rosén I
Department of Clinical Neurophysiology, University Hospital, Lund, Sweden.
Dement Geriatr Cogn Disord. 1997 Mar-Apr;8(2):110-6. doi: 10.1159/000106615.
Clinical electroencephalography is a relatively simple and inexpensive diagnostic tool with a high sensitivity for diffuse organic encephalopathy of various aetiologies but with a rather low specificity for the type of diagnosis. The highest sensitivity is shown in DAT and Parkinson dementia, and in these conditions the degree of EEG abnormality is correlated with the disease severity. Quantification of EEG makes these correlations more reliable and provides a method for monitoring therapeutic effects. Dementias with predominantly frontal pathology show much less EEG abnormality, and in these conditions the EEG is often normal despite obvious clinical dementia. Also, alcohol dementias often show normal EEG patterns. At an early stage of clinical evaluation, EEG may be useful in the discrimination of organic dementia from pseudodementia, because EEG is usually normal in depression, confusion, agitation and other psychiatric conditions. In pseudodementia due to intoxication with sedatives the EEG is usually dominated by diffuse beta activity. At the stage of differential diagnosis of an organic brain disorder, EEG cannot reliably discriminate between encephalopathies secondary to hydrocephalus, AIDS, cerebrovascular disease, B12 deficiency and primary degenerative diseases such as DAT. More specific EEG patterns are seen in acute cerebrovascular lesions, metabolic encephalopathies, i.e. of hepatic origin, Creutzfeldt-Jakob disease, herpes encephalitis, and nonconvulsive status epilepticus as possible causes of a rapidly deteriorating mental and neurological condition. Repeated EEG recordings over time would add significantly to the diagnostic information. New techniques such as topographical brain mapping, analysis of the EEG during REM sleep, coherence analysis of the EEG activity, and the combination of quantified EEG techniques with evoked potentials and event-related potentials will presumably add to the sensitivity as well as the specificity of the electrophysiological methods in the diagnosis of dementia.
临床脑电图是一种相对简单且廉价的诊断工具，对各种病因的弥漫性器质性脑病具有较高的敏感性，但诊断类型的特异性较低。在阿尔茨海默病和帕金森病痴呆中显示出最高的敏感性，在这些情况下，脑电图异常程度与疾病严重程度相关。脑电图的量化使这些相关性更可靠，并提供了一种监测治疗效果的方法。以额叶病变为主的痴呆症脑电图异常要少得多，在这些情况下，尽管临床痴呆明显，但脑电图通常正常。此外，酒精性痴呆症脑电图模式通常也正常。在临床评估的早期阶段，脑电图可能有助于区分器质性痴呆和假性痴呆，因为在抑郁症、意识模糊、躁动和其他精神疾病中脑电图通常是正常的。在因镇静剂中毒导致的假性痴呆中，脑电图通常以弥漫性β活动为主。在器质性脑疾病的鉴别诊断阶段，脑电图无法可靠地区分继发于脑积水、艾滋病、脑血管疾病、维生素B12缺乏症的脑病以及诸如阿尔茨海默病等原发性退行性疾病。在急性脑血管病变、代谢性脑病（即肝源性）、克雅氏病、疱疹性脑炎以及非惊厥性癫痫持续状态（可能是导致精神和神经状况迅速恶化的原因）中可看到更具特异性的脑电图模式。随着时间的推移进行重复脑电图记录将显著增加诊断信息。诸如脑地形图、快速眼动睡眠期间脑电图分析、脑电图活动相干分析以及将量化脑电图技术与诱发电位和事件相关电位相结合等新技术可能会提高电生理方法在痴呆诊断中的敏感性和特异性。
