Memory and mood outcomes after anterior thalamic stimulation for refractory partial epilepsy

PURPOSE Bilateral deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) reduces seizures and is relatively safe but may be accompanied by complaints of memory problems and depression. This study examined incidence of memory and depression adverse events (AE) in the SANTE study blinded phase and their relationship to objective neurobehavioral measures, baseline characteristics, quality of life and long-term neurobehavioral outcome. METHOD The neurobehavioral AE and neuropsychological data from a previously reported prospective randomized trial (SANTE) were analyzed. Reliable change indices (RCI) were calculated for memory and mood measures. Analyses examined relationships among AEs, RCIs, demographic and seizure variables, and long-term neurobehavioral outcome. RESULTS No significant cognitive declines or worsening of depression scores were observed through the blinded phase or in open-label at 7-years. Higher scores were observed at 7 years on measures of executive functions and attention. Depression and memory-related AEs were not associated with reliable change on objective measures or 7-year neurobehavioral outcome. The AEs were without significant impact on life quality. Memory and depression AEs were not related to demographic or seizure characteristics, change in seizure frequency, frequency of AE or depression report. CONCLUSION Bilateral ANT DBS was associated with subjective depression and memory AEs during the blinded phase in a minority of patients that were not accompanied by objective, long-term neurobehavioral worsening. Monitoring and neuropsychological assessment of depression and memory are recommended from a theoretical standpoint and because more memory and depression AEs occurred in the active stimulation than control group.