Fundamentals of transcranial electric and magnetic stimulation dose: definition, selection, and reporting practices.
BACKGROUND
The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose of EM stimulation and how it should be reported.


METHODS
This paper provides fundamental definitions and principles for reporting of dose that encompass any transcranial EM brain stimulation protocol.


RESULTS
The biologic effects of EM stimulation are mediated through an electromagnetic field injected (via electric stimulation) or induced (via magnetic stimulation) in the body. Therefore, transcranial EM stimulation dose ought to be defined by all parameters of the stimulation device that affect the electromagnetic field generated in the body, including the stimulation electrode or coil configuration parameters: shape, size, position, and electrical properties, as well as the electrode or coil current (or voltage) waveform parameters: pulse shape, amplitude, width, polarity, and repetition frequency; duration of and interval between bursts or trains of pulses; total number of pulses; and interval between stimulation sessions and total number of sessions. Knowledge of the electromagnetic field generated in the body may not be sufficient but is necessary to understand the biologic effects of EM stimulation.


CONCLUSIONS
We believe that reporting of EM stimulation dose should be guided by the principle of reproducibility: sufficient information about the stimulation parameters should be provided so that the dose can be replicated.
Department of Psychiatry and Behavioral Sciences, Duke University, Durham, North Carolina 27710, USA. angel.peterchev@duke.edu
Angel V
AV
Peterchev
Timothy A
TA
Wagner
Pedro C
PC
Miranda
Michael A
MA
Nitsche
Walter
W
Paulus
Sarah H
SH
Lisanby
Alvaro
A
Pascual-Leone
Marom
M
Bikson
D001921:Brain / Q000502:physiology*; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods*; D004599:Electric Stimulation Therapy / Q000295:instrumentation / Q000379:methods*; D004574:Electromagnetic Fields; D006801:Humans; D015203:Reproducibility of Results; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation / Q000379:methods*