EEG findings are often normal in Parkinson's disease. In advanced cases, however, marked slowing is noted. Sleep may be markedly abnormal with frequent awakenings, prolonged sleep latency, reduced REM sleep, periodic leg movements, and increased frequency of REM behavioral disorder.
Patients with AD carrying the sigma-4 allele have more pronounced slow-wave activity than patients with AD without the sigma-4 allele, although the disease progression rate does not change. These differences in EEG may suggest differences in the degree of the cholinergic deficit in these subgroups.
In patients with Huntington disease, EEG changes show gradual, progressive slowing and the progressive attenuation of amplitude. About 30% of the patients have low-voltage EEGs, with amplitudes < 10 μV. Epileptiform activity occurs in about 3% of cases, which tend to be juvenile. Because EEG correlates poorly with the clinical symptoms, impressive EEG changes are not observed in Pick disease.
Learn more about EEG in dementia.
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Cite this: Helmi L. Lutsep. Fast Five Quiz: Dementia Practice Essentials - Medscape - Mar 13, 2023.