1-Hz repetitive transcranial magnetic stimulation increases cerebral vasomotor reactivity: a possible autonomic nervous system modulation.
BACKGROUND
Neuromodulation techniques, i.e. repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), can modify cerebral hemodynamics. High frequency rTMS appeared to decrease cerebral vasomotor reactivity (VMR), while there is still poor evidence about the effect of low frequency (LF) rTMS on cerebral blood flow (CBF) and VMR.


OBJECTIVE
The present study aimed to test if LF rTMS decreases CBF and increases cerebral VMR. Monolateral or bilateral hemispheric involvement and duration of the effect were considered. A possible role of autonomic nervous system in CBF and VMR modulation was also investigated.


METHODS
Twenty-four right-handed healthy subjects underwent randomly real (12) or sham (12) 20-min 1-Hz rTMS on left primary motor cortex. Mean flow velocity and VMR of middle cerebral arteries were evaluated by means of transcranial Doppler before (T0), after 10 min (T1) and after 2 (T2), 5 (T3) and 24 h (T4) from rTMS. Heart rate variability (HRV) was studied within the same timing interval, assessing low frequency/high frequency (LF/HF) ratio as index of autonomic balance.


RESULTS
After real rTMS compared with sham stimulation, MFV decreased bilaterally at T1 (F = 3.240, P = .030) while VMR increased bilaterally (F = 5.116, P = .002) for at least 5 h (T3). LF/HF ratio decreased early after real rTMS (F = 2.881, P = .040).


CONCLUSIONS
1-Hz rTMS may induce a bilateral long-lasting increase of VMR, while its effect on MFV is short-lasting. Moreover, HRV changes induced by rTMS suggest a possible autonomic nervous system modulation.
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy. Electronic address: f.vernieri@unicampus.it.
Fabrizio
F
Vernieri
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Claudia
C
Altamura
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Paola
P
Palazzo
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Riccardo
R
Altavilla
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Emma
E
Fabrizio
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Rita
R
Fini
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Jean-Marc
JM
Melgari
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Matteo
M
Paolucci
Service of Medical Statistics and Information Technology (SeSMIT), AFaR, Centro "San Benedetto Menni - Fatebenefratelli", Rome, Italy; Clinical and Molecular Epidemiology, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Pisana, Rome, Italy.
Patrizio
P
Pasqualetti
Neurology Unit, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 200, Rome 00128, Italy.
Paola
P
Maggio
D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D014666:Vasomotor System / Q000502:physiology*
Cerebral hemodynamics; Cerebral vasomotor reactivity; Repetitive transcranial magnetic stimulation; Transcranial Doppler