Related Experiment Video
Updated: Nov 2, 2025
Measuring Contralateral Silent Period Induced by Single-Pulse Transcranial Magnetic Stimulation to Investigate M1 Corticospinal Inhibition
Published on: August 23, 2022
Duration and reliability of the silent period in individuals with spinal cord injury
Hannah J Sfreddo1, Jaclyn R Wecht1, Ola A Alsalman1,2
1James J. Peters VA Medical Center, Bronx, NY, USA.
Design:
Prospective cohort study.
Objectives:
We aim to better understand the silent period (SP), an inhibitory counterpart to the well-known motor evoked potential (MEP) elicited by transcranial magnetic stimulation (TMS), in individuals with spinal cord injury (SCI).
Setting:
Veterans Affairs Hospital in New York.
Methods:
EMG responses were measured in the target abductor pollicis brevis at rest (TMS at 120% of resting motor threshold (RMT)) and during maximal effort (TMS at 110% of RMT). Participants with chronic cervical SCI (n = 9) and AB participants (n = 12) underwent between 3 and 7 sessions of testing on separate days. The primary outcomes were the magnitude and reliability of SP duration, resting and active MEP amplitudes, and RMT.
Results:
SCI participants showed significantly lower MEP amplitudes compared to AB participants. SCI SP duration was not significantly different from AB SP duration. SP duration demonstrated reduced intra-participant variability within and across sessions compared with MEP amplitudes. SCI participants also demonstrated a higher prevalence of SP 'interruptions' compared to AB participants.
Conclusions:
In a small group of individuals with chronic cervical SCI, we confirmed the well-known findings that SCI individuals have lower TMS evoked potential amplitudes and a tendency toward higher TMS motor thresholds relative to able-bodied controls. We did not observe a significant difference in SP duration between individuals with versus without SCI. However, SP duration is a more reliable outcome within and across multiple sessions than MEP amplitude.
