Facial electromyography as a predictor of treatment outcome in depression

Electromyograms (EMGs) from the corrugator, zygomatic and splenius capitis muscle sites and Beck depression inventory scores were obtained from 21 depressed in-patients shortly after admission and after two weeks in hospital. Contrary to the result of a previous study by other investigators, significant covariaton between depressive symptoms and corrugator EMG levels was not seen. However, consistent with a second finding of the previous study, initial corrugator EMG levels were shown to be significantly predictive of treatment outcome. Further, initial EMG from the zygomatic was also found to predict changes in depression. The explanation is unclear and further research is needed.