Objective: Delirium in the elderly results in increased morbidity, mortality, and functional decline. Particularly in dementia delirium is underdiagnosed. To increase diagnostic accuracy, we investigated whether the maintenance of activation assessed by EEG discriminates delirium concomitant with dementia(D+D) from dementia without delirium(DP) and cognitively unimpaired elderly(CU).
Method: Routine and quantitative EEG (rEEG/qEEG) with additional prolonged activation (3min eyes-open-period) were evaluated in hospitalized elderly with acute geriatric disease. Patients were assigned post hoc to three comparable groups (D+D/DP/CU) by expert consensus based on DSM-IV criteria. Dementia diagnosis was confirmed with cognitive and functional tests and caregiver rating (IQCODE).
Results: While rEEG at rest showed low accuracy of delirium diagnosis, in qEEG DP and CU revealed a specific activation pattern of high significance found to be absent in D+D. Stepwise logistic regression confirmed that the differentiation of D+D from DP is best resolved using activated upper alpha and delta powerdensity, which, compared to rEEG, enables an 11% increase of diagnostic correctness to 83%, resulting in 67% sensitivity and 91% specificity. Among frail CU and D+D almost 90% were correctly classified.
Conclusion: Dementia associated delirium can be discriminated reliably from dementia alone in a meaningful clinical setting. Thus, EEG evaluation in chronic encephalopathy should be optimized by a simple activation task and spectral analysis especially in the demented elderly.
- EEG spectral analysis
- delirium diagnosis