A real electro-magnetic placebo (REMP) device for sham transcranial magnetic stimulation (TMS).
OBJECTIVE
There is growing interest in neuropsychiatry for repetitive transcranial magnetic stimulation (rTMS) as a neuromodulatory treatment. However, there are limitations in interpreting rTMS effects as a real consequence of physiological brain changes or as placebo-mediated unspecific effects, which may be particularly strong in psychiatric patients. This is due to the fact that existing sham rTMS procedures are less than optimal. A new placebo tool is introduced here, called real electro-magnetic placebo (REMP) device, which can simulate the scalp sensation induced by the real TMS, while leaving both the visual impact and acoustic sensation of real TMS unaltered.


METHODS
Physical, neurophysiological and behavioural variables of monophasic and biphasic single-pulse TMS and biphasic 1Hz and 20Hz rTMS procedures (at different intensities) were tested in subjects who were expert or naïve of TMS. Results of the real TMS were compared with those induced by the REMP device and with two other currently used sham procedures, namely the commercially available Magstim sham coil and tilting the real coil by 90 degrees .


RESULTS
The REMP device, besides producing scalp sensations similar to the real TMS, attenuated the TMS-induced electric field (as measured by a dipole probe) to a biologically inactive level. Behaviourally, neither expert nor naïve TMS subjects identified the "coil at 90 degrees " or the "Magstim sham coil" as a real TMS intervention, whilst naïve subjects were significantly more likely to identify the REMP-attenuated TMS as real.


CONCLUSIONS
The "goodness of sham" of the REMP device is demonstrated by physical, neurophysiological, and behavioural results.


CONCLUSIONS
Such placebo TMS is superior to the available sham procedures when applied on subjects naïve to TMS, as in case of patients undergoing a clinical rTMS trial.
Rossi
Simone
S
Dipartimento di Neuroscienze, Sezione Neurologia, Università di Siena, Policlinico Le Scotte, Viale Bracci, I-53100 Siena, Italy. rossisimo@unisi.it
Ferro
Marisa
M
Cincotta
Massimo
M
Ulivelli
Monica
M
Bartalini
Sabina
S
Miniussi
Carlo
C
Giovannelli
Fabio
F
Passero
Stefano
S
D000328:Adult; D055590:Electromagnetic Phenomena / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D010919:Placebos; D015203:Reproducibility of Results; D012535:Scalp / Q000294:innervation / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation* / Q000379:methods*
D010919:Placebos