Cognitive Performance as A Function of Right-Sided, Low-Frequency rTMS Administration Using CNS Vital Signs
Major Depressive Disorder (MDD) is a complex, widespread, and recurrent psychiatric disorder. Although the majority of affected individuals respond adequately to pharmacotherapy and/or psychotherapy, there persists a sub-population of affected individuals who do not improve despite these interventions. Electric convulsive therapy has been described in the research as the most efficacious options for treatment resistant depression. However, due to the neurocognitive deficits associated with ECT, interest in transcranial magnetic stimulation (TMS), a non-invasive approach that stimulates the cerebral cortex, as an alternative to ECT has become a major research focus. The efficacy of both high-frequency and low-frequency rTMS for depression have been well documented although the impact on neurocognitive functioning is not completely understood. Research to date has demonstrated neurocognitive improvement following rTMS to the left dorsolateral prefrontal cortex only. Therefore, this study focused on the neurocognitive changes associated with rTMS when administered to the right dorsolateral prefrontal cortex and the supplementary motor area, utilizing data from the existing EVMS registry for patients receiving TMS. Measures assessed depression (Beck Depression Inventory-II), anxiety (Beck Anxiety Inventory), and neurocognitive functioning (CNS-Vital Signs tests of executive function, cognitive flexibility, and complex attention). A series of ANOVAs were conducted to examine: a) whether statistically significant differences exist in neurocognitive scores following 2 and/or 6 weeks of rTMS treatment as compared to pre-treatment; and b) whether any significant improvements in neurocognitive scores occur independent of a reduction in depression and anxiety scores. As expected, results revealed statistically significant improvements for all three neurocognitive domains across all three time points with the greatest improvement taking place during the first two weeks of treatment with a stabilizing effect thereafter. Results also revealed changes in depression and anxiety scores that were not significantly correlated with Executive Functioning, Complex Attention, and Cognitive Flexibility change scores. Therefore this study substantiates the use of right-sided, low-frequency rTMS as a treatment alternative to ECT as it provides support for improved cognitive functions that occur independent of mood improvements.
Major depressive disorder, Neurocognition, rTMS, Clinical Psychology
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