Electrophysiological changes in late life depression and their relation to structural brain changes.
BACKGROUND
Late life depression is often accompanied by slowed information processing during neuropsychological testing, and this has been related to underlying cerebrovascular disease. We investigated whether changes in electrophysiological markers of information processing might share the same pathological correlates.


METHODS
Differences in power spectra frequency, contingent negative variation (CNV), post-imperative negative variation (PINV), and auditory P300a amplitude and latency in 19 patients with DSM-IV major depression aged ≥ 60 years were compared with 25 recordings in age-matched healthy controls. Associations with total brain volume and degree of white matter hyperintensities (WMH) were examined in those who had undergone additional magnetic resonance imaging (MRI).


RESULTS
Compared with healthy controls, patients had more slow-wave delta (group difference: p = 0.024) and theta activity (p = 0.015) as well as alpha activity (p = 0.005) but no decrease in beta band frequency (p = 0.077). None of these changes related differently to brain volume or WMH in patients or controls. Patients further showed prolonged P300a latencies (p = 0.027), which were associated with decreased total brain volume in patients but not controls (interaction by group: p = 0.004). While there were no overall differences in PINV between both groups, patients showed a decrease in PINV magnitude with increasing WMH, a relation that was not seen in controls (interaction by group: p = 0.024).


CONCLUSIONS
Patients with late life depression show changes in several electrophysiological markers of cerebral arousal and information processing, some of which relate to brain atrophy and WMH on MRI.
Köhler
Sebastian
S
School for Mental Health and Neuroscience, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands.
Ashton
C Heather
CH
Marsh
Richard
R
Thomas
Alan J
AJ
Barnett
Nicky A
NA
O'Brien
John T
JT
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D001284:Atrophy; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000473:pathology* / Q000503:physiopathology*; D004569:Electroencephalography; D004594:Electrophysiology; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D013997:Time Factors