Margherita Russo1, Domenica Crupi2, Antonino Naro3, Laura Avanzino4, Maria Buccafusca5, Vincenzo Dattola5, Carmen Terranova5, Fabrizio Sottile6, Vincenzo Rizzo5, Maria Felice Ghilardi7, Paolo Girlanda5, Marco Bove4, Angelo Quartarone5. 1. IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy. Electronic address: margheritarusso@virgilio.it. 2. Regional Epilepsy Centre "Bianchi Melacrino Morelli" Hospital, Reggio, Calabria, Italy. 3. IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy. 4. Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, Italy. 5. Department of Neuroscience, University of Messina, Italy. 6. Department of Clinical and Experimental Medicine, University of Messina, Italy. 7. Department of Physiology, Pharmacology and Neuroscience, City University of New-York, Medical School, New York, USA.
Abstract
BACKGROUND: The neural mechanisms underlying fatigue in multiple sclerosis (MS) are still poorly understood. Cortico-cortical and cortico-subcortical circuitry abnormalities may play a central role in its pathogenesis. Our previous studies suggest that central fatigue may be related to an impairment of volition drive during movement preparation. OBJECTIVE: We further explored the central mechanisms of fatigue at the premovement level in MS patients during a sustained motor task. METHODS: In MS patients with (MS-F) and without (MS-NF) fatigue and age-matched healthy controls, we evaluated the motor cortex excitability and the premovement facilitation (PMF) through transcranial magnetic stimulation before and after 5min of sequenced finger-tapping movements at a fixed frequency of 2Hz. RESULTS: In MS-F patients, the number of correct sequences performed and the ability to keep a fixed movement rate during the 5-min motor task were significantly decreased in comparison to the normal controls and MS-NF patients. Also, in MS-F patients, post-exercise PMF was significantly decreased. The PMF abnormalities were highly correlated with the performance decay. CONCLUSIONS: PMF may be considered as a kind of servo-mechanism which could play a crucial role during sustained motor task in order to prevent motor performance disruption and to avoid motor exhaustion.
BACKGROUND: The neural mechanisms underlying fatigue in multiple sclerosis (MS) are still poorly understood. Cortico-cortical and cortico-subcortical circuitry abnormalities may play a central role in its pathogenesis. Our previous studies suggest that central fatigue may be related to an impairment of volition drive during movement preparation. OBJECTIVE: We further explored the central mechanisms of fatigue at the premovement level in MSpatients during a sustained motor task. METHODS: In MSpatients with (MS-F) and without (MS-NF) fatigue and age-matched healthy controls, we evaluated the motor cortex excitability and the premovement facilitation (PMF) through transcranial magnetic stimulation before and after 5min of sequenced finger-tapping movements at a fixed frequency of 2Hz. RESULTS: In MS-F patients, the number of correct sequences performed and the ability to keep a fixed movement rate during the 5-min motor task were significantly decreased in comparison to the normal controls and MS-NF patients. Also, in MS-F patients, post-exercise PMF was significantly decreased. The PMF abnormalities were highly correlated with the performance decay. CONCLUSIONS: PMF may be considered as a kind of servo-mechanism which could play a crucial role during sustained motor task in order to prevent motor performance disruption and to avoid motor exhaustion.
Authors: Fioravante Capone; Francesco Motolese; Emma Falato; Mariagrazia Rossi; Vincenzo Di Lazzaro Journal: Front Neurol Date: 2020-04-22 Impact factor: 4.003