The effects of repetitive transcranial magnetic stimulation (rTMS) on procedural memory and dysphoric mood in patients with major depressive disorder

OBJECTIVE To study the effects of depression and treatment with repetitive transcranial magnetic stimulation (rTMS) on sequence learning. BACKGROUND Prefrontal dysfunction in depression may affect sequence learning and be amenable to normalization by rTMS. METHOD The serial reaction time test (SRTT) was administered to 19 patients with major depressive disorder (MDD) and 20 nondepressed control participants. MDD patients were examined before and following treatment with rTMS to the left dorsolateral prefrontal cortex in daily sessions of 1600 stimuli at 10 Hz and at an intensity of 110% of the motor threshold. Treatment occurred over a 2-week interval of time. RESULTS MDD and nondepressed groups differed significantly with respect to baseline response speed. Following treatment with rTMS, MDD participants demonstrated significantly improved mood, improved response speed, and improved procedural learning. CONCLUSIONS Findings suggest that rTMS over a 2-week period improves performance on tasks of response speed and procedural memory in patients with MDD. These cognitive effects are greater in those patients who showed a significant antidepressant effect to rTMS intervention