Quantified electroencephalographic changes in depressed patients with and without dementia.

We carried out quantified electroencephalograms (qEEG) in 17 patients with probable Alzheimer's disease (AD), who also met the DSM-III-R criteria for either dysthymia or major depression, and 18 AD patients with comparable intellectual impairment but no depression, 13 patients with depression but no AD, and 10 age-matched normal controls. There was a significant effect for depression in alpha relative power: depressed patients (with or without AD) showed a significantly lower alpha relative power in the right posterior region as compared to nondepressed patients; however, this change was observed over the right hemisphere in depressed non-AD patients, and in left, medial, and right posterior regions in depressed-AD patients. Depressed patients without AD showed a significant global decrease in delta power, whereas depressed patients with AD showed significant increments in delta power in posterior brain areas.

Quantified electroencephalographic correlates of neuropsychological deficits in Alzheimer's disease.

The authors examined relationships between quantified EEG (qEEG) variables and neuropsychological performance in 54 consecutive patients with probable Alzheimer's disease (AD). Patients were studied with qEEG and a neuropsychological battery that assessed memory, attention, verbal functions, set-shifting abilities, and procedural learning. More severe memory, attention, and verbal deficits were significantly correlated with lower alpha relative power, and increased theta relative power was significantly correlated with poor set-shifting abilities.

Quantified electroencephalographic correlates of depression in Alzheimer's disease.

While depression is one of the most frequent psychiatric problems among patients with probable Alzheimer's disease (AD), its mechanism is not well known. We performed quantified EEGs in a consecutive series of seven patients with mild dementia and depression, six patients with mild dementia and no depression, eight patients with moderate dementia and depression, and eight patients with moderate dementia and no depression. Regardless of the severity of dementia, depressed patients had a significantly higher percent theta in posterior brain areas.