Electroencephalography as a diagnostic tool in dementia
I. Rosen
Bok Engelsk 1997
| Utgitt | 1997
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| Omfang | Side 110- 116
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| Opplysninger | Clinical electroencephalography is a relatively simple andinexpensive diagnostic tool with a high sensitivity for diffuseorganic encephalopathy of various aetiologies but with a rather lowspecificity for the type of diagnosis. The highest sensitivity isshown in DAT and Parkinson dementia, and in these conditions thedegree of EEG abnormality is correlated with the disease severity.Quantification of EEG makes these correlations more reliable andprovides a method for monitoring therapeutic effects. Dementias withpredominantly frontal pathology show much less EEG abnormality, andin these conditions the EEG is often normal despite obvious clinicaldementia. Also, alcohol dementias often show normal EEG patterns. Atan early stage of clinical evaluation, EEG may be useful in thediscrimination of organic dementia from pseudodementia, because EEGis usually normal in depression, confusion, agitation and otherpsychiatric conditions. In pseudodementia due to intoxication withsedatives the EEG is usually dominated by diffuse beta activity. Atthe stage of differential diagnosis of an organic brain disorder, EEGcannot reliably discriminate between encephalopathies secondary tohydrocephalus, AIDS, cerebrovascular disease, B-12 deficiency andprimary degenerative diseases such as DAT. More specific EEG patternsare seen in acute cerebrovascular lesions, metabolicencephalopathies, i.e. Of hepatic origin, Creutzfeldt-Jakob disease,herpes encephalitis, and nonconvulsive status epilepticus as possiblecauses of a rapidly deteriorating mental and neurological condition.Repeated EEG recordings over time would add significantly to thediagnostic information. New techniques such as topographical brainmapping, analysis of the EEG during REM sleep, coherence analysis ofthe EEG activity, and the combination of quantified EEG techniqueswith evoked potentials and event-related potentials will presumablyadd to the sensitivity as well as the specificity of theelectrophysiological methods in the diagnosis of dementia.
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| Emner |
