QUANTITATIVE EEG CORRELATES OF OUTCOME IN OLDER PSYCHIATRIC-PATIENTS .2. 2-YEAR FOLLOW-UP OF PATIENTS WITH DEPRESSION

The authors examined quantitative electroencephalographic (QEEG) coher ence in 3 7 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 depres sion, 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-Ro landic 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 foll ow-up, low coherence was significantly associated with lower functiona l status. These findings suggest that the coherence variable measures actual neurophysiologic differences between groups of depressed patien ts and these differences are associated with the heterogeneous outcome s of depression in elderly patients.