Laterality of motor cortical function measured by transcranial magnetic stimulation threshold tracking

Introduction: Threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS) examines cortical function and is useful for diagnosis of motor neuron disorders. Differences in cortical function have been identified between dominant and non-dominant limbs using constant stimulus methods, but they remain unclear, potentially due to methodological differences. In this study we aimed to clarify differences in cortical function between dominant and non-dominant limbs using TTTMS. Methods: Single-pulse TMS, TTTMS, and nerve conduction studies were performed in 25 healthy, right-handed participants by recording from the abductor pollicis brevis muscle. Results: There were no side-to-side differences observed in resting motor threshold, motor evoked potential (MEP) amplitude, MEP latency, central motor conduction time, cortical silent period, short-interval intracortical inhibition and facilitation, compound muscle action potential (CMAP) amplitude, CMAP latency, F-wave latency, or neurophysiological index. Conclusions: These findings suggest that, when using TTTMS, there are no differences in cortical function between dominant and non-dominant hemispheres. Muscle Nerve 55: 424–427, 2017