EEG findings in dementia with Lewy bodies and Alzheimer's disease

Objectives-To evaluate the role of the EEG in the diagnosis of dementia wit h Lewy bodies (DLB). Methods-Standard EEG recordings from 14 patients with DLB confirmed at post mortem were examined and were compared with the records from 11 patients wi th Alzheimer's disease confirmed at postmortem. Results-Seventeen of the total of 19 records from the patients with DLB wer e abnormal. Thirteen showed loss of alpha activity as the dominant rhythm a nd half had slow wave transient activity in the temporal lobe areas. This s low wave transient activity correlated with a clinical history of loss of c onsciousness. The patients with Alzheimer's disease were less Likely to sho w transient slow waves and tended to have less marked slowing of dominant r hythm. Conclusions-The greater slowing of the EEG in DLB than in Alzheimer's disea se may be related to a greater loss of choline acetyltransferase found in D LB. Temporal slow wave transients may be a useful diagnostic feature in DLB and may help to explain the transient disturbance of consciousness which i s characteristic of the disorder.