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. CLINICAL IMPLICATIONS: Seizure measures at first ECT may guide selection of ECT schedule to optimize ECT. LIMITATIONS: The study examined short term antidepressant effects only. The results may not be generalized to medication-resistant depressives.

Once vs. three times weekly ECT in melancholia: a randomized controlled trial.

Once weekly and three times weekly schedules of ECT, each at two stimulus dose levels (high and low), were compared for therapeutic efficacy in melancholia. Three times weekly ECTs were more efficacious than once weekly ECTs. A high stimulus dose did not enhance the efficacy of once weekly ECTs. However, the patients who remitted did so over a comparable time-course regardless of the ECT schedule. Although three times weekly ECTs are superior, 55% of patients responded to once weekly ECTs. There is therefore a need for research to identify the patients for whom once weekly ECT may be sufficient.

EEG seizure in bilateral ECT is different between low and high stimulus doses.

Melancholic depressive patients referred for ECT were randomized to receive either low dose (n = 20) or high dose (n = 20) stimulus applied bifrontotemporally. The two stimulus groups were comparable on the clinical variables. The EEG seizure was recorded on two channels (right and left frontal), digitized, coded and analyzed offline without knowledge of ECT parameters. EEG seizure was of comparable duration in the two stimulus (high dose and low dose) groups. A new composite measure, Strength-Symmetry-Index (SSI), based on strength and symmetry of seizure EEG was computed using fractal geometry. The SSI of the early-seizure was higher in the high dose than in the low dose ECT group. In a stepwise, logistic regression model, this variable contributed to 65% with correct classification of high dose and low dose ECT seizures.

Gender but not stimulus parameters influence prolactin response to electroconvulsive therapy.

The post-ictal prolactin (PRL) response represents one of the most consistent findings of electroconvulsive therapy (ECT), but correlates variably with the gender of the patient, ECT stimulus waveform, dose and electrode placement. Forty patients with endogenous depression (29 drug-naive) received either high-energy (240 mC) or low-energy (60 mC) bilateral brief-pulse ECT once or three times a week. The PRL and growth hormone (GH) levels were estimated using double antibody radioimmunoassay. The average post-ECT PRL levels differed significantly from the pre-ECT levels, with a seven- to nine-fold increase in PRL at each week of treatment. No such difference was observed in the GH levels. All patients showed an increase in PRL levels, whereas 42% failed to show an increase in GH levels. The delta PRL response (difference between post-ECT and pre-ECT serum hormone levels) was not significantly different between the drug-naive and medicated patients nor between the high-energy and low-energy groups at first ECT. Similarly, no difference was observed between the once-weekly and thrice-weekly groups at the third week of ECT. At each week of treatment, the delta PRL was significantly higher in females than in males, unlike the GH response. Electroencephalographic (EEG) seizure duration did not correlate with either delta PRL or delta GH at first ECT and third week ECT. Apart from gender, none of the variables, such as age, baseline severity of illness, presence of psychotic symptoms, drug-naive status, stimulus dose, seizure duration, seizure strength, pattern and symmetry, frequency of ECT and degree of improvement predicted the delta PRL response. Neither stimulus energy nor frequency of ECT had a significant effect on PRL response. Gender differences in PRL response to ECT merit further investigations.

Strength Symmetry Index: a measure of seizure adequacy in ECT.

Seizure electroencephalography (EEG) was recorded from two channels--right (Rt) and left (Lt)--during bilateral electroconvulsive therapy (ECT) (n = 12) and unilateral ECT (n = 12). The EEG was also acquired into a microcomputer and was analyzed without knowledge of the clinical details. EEG recordings of both ECT procedures yielded seizures of comparable duration. The Strength Symmetry Index (SSI) was computed from the early- and midseizure phases using the fractal dimension of the EEG. The seizures of unilateral ECT were characterized by significantly smaller SSI in both phases. More unilateral than bilateral ECT seizures had a smaller than median SSI in both phases. The seizures also differed on other measures as reported in the literature. The findings indicate that SSI may be a potential measure of seizure adequacy that remains to be validated in future research.