Eeg spectral characteristics in resistant depression patients on transcranial magnetic stimulation treatment

Abstract

to examine the EEG spectral characteristics during TMS in resistant depression therapy. The sample consisted of 32 depressive patients diagnosed with recurrent depressive disorder or bipolar affective disorder. TMS, as well as EEG, were conducted during the previous inefficient thymoanaleptic therapy with reduced doses. TMS was performed in the left prefrontal cortex. Treatment course consisted of 15 procedures with 100% threshold intensity. During a single procedure, the patient received 20 cycles of stimulation pulses with the frequency of 15 Hz, duration of 20 seconds and interval of 60 seconds between single cycles. EEG was recorded with the use of the «NEURO-KM» apparatus (Russia) with band pass from 0.5 to 45 Hz and time constant of 0.3 sec before and after the course of TMS. Spectroscopic analysis of EEG was conducted using the Fast Furies Transformation analysis with average of no less than 30 periods for 2 seconds with subsequent mapping with the use of the «BRAINSYS» system (Russia). After conducting TMS, EEG changes were generalized and included the reconstruction of all frequencies of the electrical brain activity. However, the major changes were seen in alpha-rhythm spectrums: its index increased in all cortical areas, mostly in the occipital cortex, thereby forming the alpha-rhythm focus in these areas.