Non-Conscious Negativity Bias as a Predictor of Depression Severity in TMS Patients

Abstract

Abstract Background: Patients who undergo TMS (transcranial magnetic stimulation) are typically assessed using subjective rating scales. However, more objective assessments may lead to the development of biomarkers that may be better able to predict outcomes after TMS. In this study, we evaluated the non-conscious negativity bias test as an objective measure of depression severity. Design: This was a retrospective study of a convenience sample of 8 patients undergoing TMS treatment for major depression. Patients took a test of non-conscious negativity bias from a computerized platform (Total Brain). This test involved patients recognizing a facial emotional expression (fear, anger, disgust, sadness, happiness, or neutrality) as quickly as possible. After this first task, a set of two faces was presented, with one face repeated from the previous first task, and one face new. Both faces displayed the same emotion, and the task was to select the face seen from the previous task. Raw scores were time to correct responses for each of the four negative emotions (fear, sadness, anger, and disgust). Raw scores were converted to a percentile score based on age, education level, and gender. Percentiles of 1-30 were categorized as low, 30-70 as medium, and 70-100 as high. Results: Out of 4 patients who scored in the low category on the test, all of them (100%) rated their depression on the PHQ9 in the moderately severe to severe range (15-27). Out of the 4 who were not in the low category on the test, 1 rated their depression on the PHQ9 as severe (25%). Using the Fisher Exact test, the association between the variables approached significance (p=0.14). Discussion: In this retrospective study, results from an implicit negative bias test were suggestive of depression severity in patients undergoing TMS. A larger sample size may help clarify its use in real-world populations. Research Category and Technology and Methods Clinical Research: 10. Transcranial Magnetic Stimulation (TMS) Keywords: TMS, Depression, Biomarker, Cognitive