Cognitive correlates of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant depression- a pilot study

Patients received forty 20-min sessions of fast-frequency (10 Hz) rTMS of the left dorsolateral prefrontal cortex (DLPFC) over 20 days. Concept-shift ability (accuracy and duration of performance) was assessed daily with a Modified Concept-Shifting Task (mCST) in patients and in eight healthy volunteers. General cognitive functioning test (Repeatable Battery for the Assessment of Neuropsychological Status; RBANS), Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HAM-D) were applied before the first and after the last rTMS.Compared to before rTMS on the first 10 days, the patients performed the mCST significantly more accurately after rTMS on the last 10 days (p？<？.001, partial eta squared=.78) while the same comparison in healthy volunteers was not statistically significant (p？=？.256, partial eta squared=.18). A significant improvement in immediate memory on RBANS and reduction in BDI and HAM-D scores were also observed after the last compared to before the first rTMS.The rTMS is associated with an improvement in selective cognitive functions that is not explained by practice effects on tasks administered repeatedly.Name: "Repetitive Transcranial Magnetic Stimulation (rTMS) in the treatment of depression, assessed with HAM-D over a four week period."URL: www.actr.org.auRegistration number: ACTRN012605000145606A repetitive transcranial magnetic stimulation (rTMS) is either a slow-frequency (≤1 Hz) or a fast-frequency (>1 Hz) non-invasive brain stimulation method [1]. A number of meta-analyses have shown that the rTMS appears to have antidepressive properties although the effect sizes were only modest, most likely due to different rTMS protocols adopted and different methods of meta-analysis used for (review see [2,3]). When focusing on the location and frequency of stimulation, it appears that such antidepressive properties are associated specifically with the left frontal fast-frequency rTMS [4]. The rTMS appears especially promising for approxi