Local and Transient Changes of Sleep Spindle Density During Series of Prefrontal Repetitive Transcranial Magnetic Stimulation in Patients With a Major Depressive Episode

The neuromodulatory effects of brain stimulation therapies notably involving repetitive transcranial magnetic stimulation (rTMS) on nocturnal sleep, which is critically disturbed in major depression and other neuropsychiatric disorders, remain largely undetermined. We have previously reported in major depression patients that prefrontal rTMS sessions enhanced their slow wave activity (SWA) power, but not their sigma power which is related to sleep spindle activity, for electrodes located nearby the stimulation site. In the present study, we focused on measuring the spindle density to investigate cumulative effects of prefrontal rTMS sessions on the sleep spindle activity. Fourteen male inpatients diagnosed with medication-resistant unipolar or bipolar depression were recruited and subjected to 10 daily rTMS sessions targeting the left dorsolateral prefrontal cortex (DLPFC). All-night polysomnography (PSG) data was acquired at four time points: Adaptation, Baseline, Post-1 (follow-up after the fifth rTMS session), and Post-2 (follow-up after the tenth rTMS session). Clinical and cognitive evaluations were longitudinally performed at Baseline, Post-1, and Post-2 time points to explore associations with the spindle density changes. The PSG data from 12 of 14 patients was analyzed to identify sleep spindles across the sleep stages II–IV at four electrode sites: F3 (frontal spindle near the stimulation site), F4 (contralateral homologous frontal region), P3 (parietal spindle in the hemisphere ipsilateral to the stimulation site), and P4 (contralateral parietal region). Statistical analysis by two-way ANOVA revealed that spindle density at F3 increased at Post-1 but decreased at Post-2 time points. Moreover, the local and transient increase of spindle density at F3 was associated with the previously reported SWA power increase at F3, possibly reflecting a shared mechanism of thalamocortical synchronization locally enhanced by diurnal prefrontal rTMS sessions. Clinical and cognitive correlations were not observed in this dataset. These findings suggest that diurnal rTMS sessions transiently modulate nocturnal sleep spindle activity at the stimulation site, although clinical and cognitive effects of the local changes warrant further investigation.

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A 6-month follow-up study on response and relapse rates following an acute trial of repetitive transcranial magnetic stimulation in patients with major depression

CNS Spectrums ◽

10.1017/s1092852920001807 ◽

2020 ◽

pp. 1-6

Author(s):

Chiara Arici ◽

Beatrice Benatti ◽

Rita Cafaro ◽

Laura Cremaschi ◽

Luca Degoni ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Major Depression ◽

Magnetic Stimulation ◽

Rating Scale ◽

Repetitive Transcranial Magnetic Stimulation ◽

High Rate ◽

Late Response ◽

Young Mania ◽

Relapse Rates

Abstract Background Little is known about the post-acute effects of repetitive transcranial magnetic stimulation (rTMS) in patients with major depression. The present study focused on the 6-month follow-up of a sample of patients with major depression, after the completion of an acute 4 weeks rTMS trial, with the aim of evaluating response (in terms of sustained and late response) and relapse rates. Methods Following the completion of an acute trial of rTMS (T0-T4), 31 drug-resistant depressed patients (bipolar or unipolar) entered a naturalistic follow-up period of 6 months, with three timepoints (T5, T6, and T7) during which they were assessed with the Hamilton Depression Rating Scale and the Young Mania Rating Scale. Results Results showed that in the 6 months following an acute transcranial magnetic stimulation (TMS) trial, a higher rate of late responders was observed among previously acute TMS nonresponders (63.64%, 7 out of 11) compared to the rate of relapse among those who had acutely responded to TMS (10%, 2 out of 20). In addition, an overall high rate of maintained response (90%) was observed. Conclusion Present findings seem to support the possibility of obtaining a clinical response also after the end of an acute TMS trial in patients with major depression. The concomitant low rate of relapse observed at the end of follow-up along with a high rate of maintained response provides further support to the post-acute efficacy of TMS. Nonetheless, further controlled studies, with larger samples and longer follow-up observation, are needed to confirm the reported results.

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