Relation between electroconvulsive therapy, cognitive side effects, neuron specific enolase, and protein S-100

To investigate whether electroconvulsive therapy (ECT) induces brain tissue damage expressed as an increase in neuron specific enolase and protein S-100.

A total of 179 serial measurements of S-100 and NSE serum concentrations were performed on 14 patients during the course of a bilaterally stimulated ECT series. Cognitive performance was assessed by psychometric testing carried out on the day before the start of ECT as well as on the days after the third, sixth, and last ECT. Pre-ECT and post-ECT concentrations of NSE and S-100 were compared by non-parametric tests.

On average, 9.5 (SD 2.9) (range 3-12) ECTs were applied; 13 of 14 patients received at least six ECTs. The average duration of convulsion (computed for all ECTs) was 29.0 (SD 10.5) seconds. At no point during the ECT series was there a significant increase in the average NSE or S-100 concentrations compared with the baseline investigation before the start of the ECT series. The maximal measured post-ECT values of NSE and S-100 were 26.6 ng/ml and 0.46 ng/ml, respectively. The cumulative energy doses applied, seizure durations, and ECT induced changes in cognitive performance scores were never significantly correlated with the NSE or S-100 serum concentrations.

This pattern of findings suggests that a modern ECT, fulfilling current quality standards, induces no brain tissue damage detectable by changes in NSE or protein S-100.