Post-seizure EEG fractal dimension of first ECT predicts antidepressant response at two weeks.
BACKGROUND
Duration of seizure by itself is an insufficient criterion for a therapeutically adequate seizure in ECT. Therefore, measures of seizure EEG other than its duration need to be explored as indices of seizure adequacy and predictors of treatment response. We measured the EEG seizure using a geometrical method-fractal dimension (FD) and examined if this measure predicted remission.


METHODS
Data from an efficacy study on melancholic depressives (n = 40) is used for the present exploration. They received thrice or once weekly ECTs, each schedule at two energy levels - high or low energy level. FD was computed for early-, mid- and post-seizure phases of the ictal EEG. Average of the two channels was used for analysis.


RESULTS
Two-thirds of the patients (n = 25) were remitted at the end of 2 weeks. As expected, a significantly higher proportion of patients receiving thrice weekly ECT remitted than in patients receiving once weekly ECT. Smaller post-seizure FD at first ECT is the only variable which predicted remission status after six ECTs. Within the once weekly ECT group too, smaller post-seizure FD was associated with remission status.


CONCLUSIONS
Post-seizure FD is proposed as a novel measure of seizure adequacy and predictor of treatment response.


CONCLUSIONS
Seizure measures at first ECT may guide selection of ECT schedule to optimize ECT.


CONCLUSIONS
The study examined short term antidepressant effects only. The results may not be generalized to medication-resistant depressives.
Gangadhar
B N
BN
Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India.
Subbakrishna
D K
DK
Janakiramaiah
N
N
Motreja
S
S
Narayana Dutt
D
D
Paramehwara
G
G
D000328:Adult; D003866:Depressive Disorder / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy*; D004311:Double-Blind Method; D004565:Electroconvulsive Therapy / Q000379:methods*; D004569:Electroencephalography; D005260:Female; D017709:Fractals; D006801:Humans; D016015:Logistic Models; D008297:Male; D017711:Nonlinear Dynamics; D011379:Prognosis; D012640:Seizures / Q000175:diagnosis* / Q000523:psychology; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome