High frequency repetitive transcranial magnetic stimulation decreases cerebral vasomotor reactivity.
OBJECTIVE
Repetitive Transcranial Magnetic Stimulation (rTMS) has been recently employed as a therapeutic strategy for stroke, although its effects on cerebral hemodynamics has been poorly investigated. This study aims to examine the impact of high frequency rTMS on cerebral vasomotor reactivity (VMR).


METHODS
Twenty-nine healthy subjects were randomly assigned to real (19) or sham 17-Hz rTMS, applied on primary motor cortex (M1) of the dominant hemisphere. All subjects underwent Transcranial Doppler of the middle cerebral arteries to evaluate mean flow velocity and VMR before (T(0)) and within 10 min (T(1)) following rTMS. Four subjects underwent further VMR evaluations at 2 (T(2)), 5 (T(3)) and 24 h (T(4)) after rTMS. As a control condition, 10 subjects underwent real (5) or sham rTMS on calcarine cortex. In addition, five acute stroke patients underwent five daily rTMS sessions on the affected hemisphere mimicking a therapeutic trial.


RESULTS
Following real rTMS on M1 (p=0.002) and calcarine cortex (p<0.001) VMR decreased with respect to T(0) in both hemispheres, while no change was observed after sham rTMS (p>0.6). VMR tended to remain lower than T(0) until T(3.) Cerebral VMR decreased independently of the stimulated side also in the patients' group.


CONCLUSIONS
High frequency rTMS reduces cerebral VMR, possibly as a secondary effect on autonomic control of cerebral hemodynamics.


CONCLUSIONS
The effect of rTMS on cerebral hemodynamics should be carefully considered before proceeding toward a therapeutic application in stroke patients.
Neurologia Clinica, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Roma 00128, Italy. f.vernieri@unicampus.it
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Rossini
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001341:Autonomic Nervous System / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000294:innervation* / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D014057:Tomography, X-Ray Computed; D050781:Transcranial Magnetic Stimulation; D017585:Ultrasonography, Doppler, Transcranial; D014666:Vasomotor System / Q000502:physiology*