Quantitative EEG Correlates of Outcome in Older Psychiatric Patients: Part II: Two-Year Follow-Up of Patients With...

The authors examined quantitative electroencephalographc (QEEG) coherence in 37 depressed elderly patients and performed 2-year follow-up evaluations. All subjects had equivocal cognitive impairment, but none had delirium or dementia. More than 40% (16/37) recovered from depression, and 38% (14/37) remained well for 2 years. Twenty-four percent (n = 9) had died within 2 years, most from cardiac causes. Low trans-Rolandic coherence from the left hemisphere was strongly associated with mortality: 44% (7/16) of those with low coherence died, and 78% (7/9) of those who died had low coherence. Among survivors (n = 28) at follow-up, low coherence was significantly associated with lower functional status. These findings suggest that the coherence variable measures actual neurophysiology differences between groups of depressed patients and these differences are associated with the heterogeneous outcomes of depression in elderly patients.