Comparison of the delta EEG in the first and second non-REM periods in depressed adults and normal controls.

The distribution of period-analyzed delta activity in the first and second non-rapid eye movement (NREM) periods was compared in nine symptomatic depressed outpatients and nine normal controls. The groups did not differ in ratios of delta zero-cross or delta power in the first to the second NREM periods. Further, neither group showed a systematic change in delta count or delta power across the first two NREM periods. Our findings suggest that ratios of delta activity in the first two NREM periods may not systematically differentiate depressed adults from normal subjects.