Objective: previous reports hypothesized a dysfunction of motor skill learning in Restless Legs Syndrome (RLS) in terms of decreased movement-related cortical plasticity; however, a direct demonstration of impaired plasticity is lacking. We aim to probe the short-term mechanisms of cortical plasticity through repetitive transcranial magnetic stimulation (rTMS) in idiopathic RLS. Materials and methods: motor evoked potentials (MEPs) during inhibitory rTMS were recorded, using a figure-of-eight coil, from the right first dorsal interosseus muscle of 6 right-handed RLS patients and 6 age-matched controls. By using a stimulus intensity of 110% of the resting motor threshold (rMT), a single session of low-frequency (1 Hz) rTMS over the left primary motor cortex was performed in the evening. The session consisted of 20 trains and 50 stimuli per train (1,000 stimuli in total), with an intertrain interval of 30 s. Results: no difference was found for the rMT. Smaller MEPs amplitude at the end of the rTMS were observed in all subjects, although this was significantly more evident in controls than in patients. Conclusion: compared to controls, RLS subjects exhibited only partially inhibitory rTMS-induced motor cortex plasticity, suggesting an impairment of GABA-mediated short-term mechanisms of excitability and plasticity. This finding, although preliminary, might be viewed as a target of specific non-invasive brain stimulation techniques modulating sensory-motor cortical networks in RLS.

Impaired short-term cortical plasticity in Restless Legs Syndrome: a pilot rTMS study

Lanza G
Primo
;
Bella R
Penultimo
;
2016

Abstract

Objective: previous reports hypothesized a dysfunction of motor skill learning in Restless Legs Syndrome (RLS) in terms of decreased movement-related cortical plasticity; however, a direct demonstration of impaired plasticity is lacking. We aim to probe the short-term mechanisms of cortical plasticity through repetitive transcranial magnetic stimulation (rTMS) in idiopathic RLS. Materials and methods: motor evoked potentials (MEPs) during inhibitory rTMS were recorded, using a figure-of-eight coil, from the right first dorsal interosseus muscle of 6 right-handed RLS patients and 6 age-matched controls. By using a stimulus intensity of 110% of the resting motor threshold (rMT), a single session of low-frequency (1 Hz) rTMS over the left primary motor cortex was performed in the evening. The session consisted of 20 trains and 50 stimuli per train (1,000 stimuli in total), with an intertrain interval of 30 s. Results: no difference was found for the rMT. Smaller MEPs amplitude at the end of the rTMS were observed in all subjects, although this was significantly more evident in controls than in patients. Conclusion: compared to controls, RLS subjects exhibited only partially inhibitory rTMS-induced motor cortex plasticity, suggesting an impairment of GABA-mediated short-term mechanisms of excitability and plasticity. This finding, although preliminary, might be viewed as a target of specific non-invasive brain stimulation techniques modulating sensory-motor cortical networks in RLS.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/372438
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