Response to venlafaxine on EEG in unmedicated bipolar depression: which entropy, up or down?

Sermin Kesebir, Sultan Tarlacı, Rüştü Murat Demirer, Nevzat Tarhan

Üsküdar University, NPİstanbul Brain Hospital, İstanbul, Turkey

DOI 10.36148/2284-0249-411


We examined changes in the entropy area in bipolar depression patients at baseline and at the end of the first hour following per oral 75 mg venlafaxine intake.


For this purpose, 10 patients diagnosed with bipolar disorder type I, depressive episode according to DSM-5, who applied to our outpatient unit and gave voluntary consent for our study were evaluated consecutively. EEG was taken at the end of the first hour following basal and per oral 75 mg venlafaxine intake. Different entropies were calculated by transferring the last sample digital data with EZ-Entropy software. EZ-Entropy software is a free distributed program that automatically and also user friendly calculates entropy. It basically works via the MathLab interface. 


Four entropy types among seven types of entropies are increased (ApEn, SampEn, FuzzyEn, PemEn), while three entropy types decreased (DistEn, CEn, SDEn). All these mean entropy changes in increases and decreases were statistically significant under paired samples t-test correlation results.


Pathologies thus seem to reduce the brain’s adaptation ability to response stimuli, or in other words make the brain less prone to deviate from equilibrium. This is nevertheless not homogeneous.

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