Resting-State Electroencephalogram Complexity Is Associated With Oral Ketamine Treatment Response: A Bayesian Analysis of Lempel-Ziv Complexity and Multiscale Entropy.
Brain and behavior November 1, 2024 Jules S Mitchell, Toomas E Anijärv, Adem T Can et al.
Subanesthetic doses of ketamine show promise for treating suicidality, but predictive biomarkers are lacking. This study examined EEG-derived complexity measures—Lempel-Ziv complexity (LZC) and multiscale entropy (MSE)—in 31 participants receiving six weekly oral doses of racemic ketamine (0.5-3 mg/kg). Responders, defined by a ≥50% reduction in Beck Suicide Scale score or a score ≤6, showed elevated baseline eyes-open complexity compared to nonresponders, which decreased from baseline to post-treatment. Elevated baseline eyes-open LZC in responders was localized to the left frontal lobe. EEG complexity metrics may serve as sensitive biomarkers for predicting and evaluating oral ketamine treatment response.