High (15 Hz) and low (1 Hz) frequency transcranial magnetic stimulation have different acute effects on regional cerebral blood flow in depressed patients

• Published in: Psychological medicine 2003-08, Vol.33 (6), p.997-1006
• Main Authors: LOO, C. K., SACHDEV, P. S., HAINDL, W., WEN, W., MITCHELL, P. B., CROKER, V. M., MALHI, G. S.
• Format: Article
• Language: English
• Subjects: Adult; Anxiety - diagnosis; Biological and medical sciences; Blood flow; Brain - blood supply; Brain - metabolism; Cortical activation; Depression; Depressive Disorder, Major - diagnosis; Depressive Disorder, Major - psychology; Depressive Disorder, Major - therapy; Diagnostic and Statistical Manual of Mental Disorders; Female; Functional Laterality - physiology; Hemodynamics - physiology; High frequency; Humans; Male; Medical sciences; Miscellaneous; Outcomes; Oximes - pharmacokinetics; Prefrontal Cortex - blood supply; Prefrontal Cortex - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Radio Waves; Radiopharmaceuticals - pharmacokinetics; Severity of Illness Index; Single photon emission computed tomography; Skull; Tomography, Emission-Computed, Single-Photon; Transcranial magnetic stimulation; Transcranial Magnetic Stimulation - instrumentation; Treatment; Treatments
• ISSN: 0033-2917; 1469-8978
• DOI: 10.1017/S0033291703007955

Background. High and low frequency repetititve transcranial magnetic stimulation (rTMS) are both effective in treating depression but have contrary effects on motor cortical activity. This study aimed to understand further the mechanisms of action of high and low frequency rTMS by examining their acute effects on regional cerebral blood flow (rCBF) in depressed patients. Method. Eighteen depressed subjects underwent brain single photon emission computerized tomography (SPECT) scanning using split-dose 99mTc-HMPAO, and were examined during sham and active rTMS to the left prefrontal cortex, at 15 Hz or 1 Hz (N=9 each). Relative rCBF changes were examined by statistical parametric mapping and by regions of interest analysis. Results. High (15 Hz) frequency rTMS resulted in relative rCBF increases in the inferior frontal cortices, right dorsomedial frontal cortex, posterior cingulate and parahippocampus. Decreases occurred in the right orbital cortex and subcallosal gyrus, and left uncus. Low (1 Hz) frequency rTMS led to increased relative rCBF in the right anterior cingulate, bilateral parietal cortices and insula and left cerebellum. High frequency rTMS led to an overall increase, whereas low frequency rTMS produced a slight decrease, in the mean relative rCBF in the left dorsolateral prefrontal cortex. Conclusions. High (15 Hz) and low (1 Hz) frequency rTMS led to different frontal and remote relative rCBF changes, which suggests different neurophysiological and possibly neuropsychiatric consequences of a change in frequency of rTMS.