Intraclass correlations of seizure duration by wavelet transform, sample entropy, and visual determination in electroconvulsive therapy

Electric Field, Ictal Theta Power, and Clinical Outcomes in Electroconvulsive Therapy

BACKGROUND

Electroconvulsive therapy (ECT) is efficacious for treatment-resistant depression. Treatment-induced cognitive impairment can adversely impact functional outcomes. Our pilot study linked the electric field to ictal theta power from a single suprathreshold treatment and linked ictal theta power to changes in phonemic fluency. In this study, we set out to replicate our findings and expand upon the utility of ictal theta power as a potential cognitive biomarker.

METHODS

Twenty-seven participants (18 female and 9 male) received right unilateral ECT for treatment-resistant depression. Pre-ECT magnetic resonance imaging and finite element modeling determined the 90th percentile maximum electric field in the brain. Two-lead electroencephalographs were digitally captured across the ECT course, with the earliest suprathreshold treatment used to determine power spectral density. Clinical and cognitive outcomes were assessed pre-, mid-, and post-ECT. We assessed the relationship between the electric field in the brain, ictal theta power, clinical outcome (Inventory of Depressive Symptomatology), and cognitive outcomes (phonemic and semantic fluency) with linear models.

RESULTS

Ictal theta power in the Fp1 and Fp2 channels was associated with the electric field, antidepressant outcome, and phonemic and semantic fluency. The relationship between ictal theta power and phonemic fluency was strengthened in the longitudinal analysis. The electric field in the brain was directly associated with phonemic and semantic fluency but not with antidepressant outcome.

CONCLUSIONS

Ictal theta power is a potential cognitive biomarker early on in the ECT course to help guide parameter changes. Larger studies are needed to further assess ictal theta power's role in predicting mood outcome and changes with ECT parameters.

Intraclass correlations of seizure duration by wavelet transform, sample entropy, and visual determination in electroconvulsive therapy

Although electroconvulsive therapy seizure duration has been shown to have limited relevance to efficacy, seizure duration remains important for clinically valid stimulus efficiency. There has been no report on seizure duration using sample entropy with Thymatron (Somatics, Inc), which is widely used in Japan. Furthermore, wavelet transform analysis is also suitable for a seizure because of the wide range of dominant frequencies. Therefore, in this study with Thymatron, the intraclass correlations of seizure duration determined by sample entropy, wavelet transform, and visual determination were investigated to determine whether these methods were applicable for clinical use. Wavelet transform, sample entropy, and the human rater had high intraclass correlations for seizure duration. The present results indicate that wavelet transform and sample entropy can be useful in the clinical electroconvulsive therapy setting, and they may also be suitable for clinical research into the mechanisms of the generalized tonic‐clonic seizures related to the efficacy of electroconvulsive therapy.

The intraclass correlations of electroconvulsive therapy‐induced seizure duration determined by sample entropy, wavelet transform, and visual determination were investigated to determine whether these methods were applicable for clinical use. sample entropy, wavelet transform, and the human rater had high intraclass correlations for the seizure durations. The present results indicate that sample entropy and wavelet transform can be useful in the clinical electroconvulsive therapy setting.