Cortical involvement in myopathies: insights from transcranial magnetic stimulation

Publication date: Available online 3 August 2017
Source:Clinical Neurophysiology
Author(s): Raffaele Nardone, Viviana Versace, Luca Sebastianelli, Francesco Brigo, Stefan Golaszewski, Monica Christova, Eugen Gallasch, Leopold Saltuari, Eugen Trink
OBJECTIVEThere is increasing evidence that an involvement of central nervous system (CNS) can occur in several myopathies. Transcranial magnetic stimulation (TMS) may represent a valuable tool for investigating important neurophysiological and pathophysiological aspects of cortical involvement in neuromuscular disorders. In this review paper we aimed to perform a systematic search of the studies employing TMS techniques in subjects suffering from myopathies.METHODSA literature search was conducted using PubMed and Embase. We identified and reviewed 9 articles matching the inclusion criteria. One hundred twenty patients were included in these studies, which have applied TMS in patients with muscle disorders.RESULTSTo date, a few studies using TMS have been performed in myopathic patients and detected subclinical abnormalities in cortical reactivity and plasticity. The most consistent finding was a decrease in intracortical inhibition, which likely represents a non-specific compensatory mechanism of the CNS in an attempt to overcome the muscle deficit through an increase of the motor cortex output to deficient muscles.CONCLUSIONSApplication of TMS to characterize the pathophysiology of the CNS in these subjects appears to be safe and may lead to the development of valuable biomarkers. Well-defined motor cortical excitability patterns can be identified in the different muscle diseases, even if preliminary findings should be confirmed in future studies in larger cohorts of patients.SIGNIFICANCETMS studies may shed new light on the physiological and pathophysiological mechanisms underlying the cortical involvement in muscle disorders.



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