Fatigue in patients with multiple sclerosis: from movement preparation to motor execution.
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.
IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy. Electronic address: margheritarusso@virgilio.it.
Margherita
M
Russo
Regional Epilepsy Centre "Bianchi Melacrino Morelli" Hospital, Reggio, Calabria, Italy.
Domenica
D
Crupi
IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy.
Antonino
A
Naro
Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, Italy.
Laura
L
Avanzino
Department of Neuroscience, University of Messina, Italy.
Maria
M
Buccafusca
Department of Neuroscience, University of Messina, Italy.
Vincenzo
V
Dattola
Department of Neuroscience, University of Messina, Italy.
Carmen
C
Terranova
Department of Clinical and Experimental Medicine, University of Messina, Italy.
Fabrizio
F
Sottile
Department of Neuroscience, University of Messina, Italy.
Vincenzo
V
Rizzo
Department of Physiology, Pharmacology and Neuroscience, City University of New-York, Medical School, New York, USA.
Maria Felice
MF
Ghilardi
Department of Neuroscience, University of Messina, Italy.
Paolo
P
Girlanda
Department of Experimental Medicine, Section of Human Physiology and Centro Polifunzionale di Scienze Motorie, University of Genoa, Italy.
Marco
M
Bove
Department of Neuroscience, University of Messina, Italy.
Angelo
A
Quartarone
D000328:Adult; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009044:Motor Cortex / Q000503:physiopathology*; D009068:Movement / Q000502:physiology*; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D014836:Volition; D055815:Young Adult
Fatigue; Kinematic parameters; Motor task; Multiple sclerosis; Premotor facilitation; Transcranial magnetic stimulation