Attention-related changes in short-term cortical plasticity help to explain fatigue in multiple sclerosis. (September 2016)

• Record Type: Journal Article
• Authors: Conte, Antonella; Li Voti, Pietro; Pontecorvo, Simona; Quartuccio, Maria Esmeralda; Baione, Viola; Rocchi, Lorenzo; Cortese, Antonio; Bologna, Matteo; Francia, Ada; Berardelli, Alfredo
• Is Part Of: Multiple sclerosis. Volume 22:Number 10(2016)
• Page Start: 1359
• Page End: 1366
• Publication Date: 2016-09
• Subjects: Multiple sclerosis -- fatigue -- attention -- 5-Hz rTMS -- paired associative stimulation -- cortical plasticity; Central nervous system -- Diseases -- Periodicals; Myelin sheath -- Diseases -- Periodicals; Inflammation -- Periodicals; Multiple sclerosis -- Periodicals; Central Nervous System Diseases -- Periodicals; Demyelinating Diseases -- Periodicals; Inflammation -- Periodicals; Multiple Sclerosis -- Periodicals; Système nerveux central -- Maladies -- Périodiques; Gaine de myéline -- Maladies -- Périodiques; Inflammation (Pathologie) -- Périodiques; Sclérose en plaques -- Périodiques; Electronic journals; 616.834005
• DOI: 10.1177/1352458515619780
• Languages: English
• ISSNs: 1352-4585

Abstract

Background: In multiple sclerosis (MS), pathophysiology of fatigue is only partially known. Objective: The aim of this study was to investigate whether the attention-induced modulation on short- and long-term cortical plasticity mechanisms in primary motor area (M1) is abnormal in patients with MS-related fatigue. Methods: All participants underwent 5-Hz repetitive transcranial magnetic stimulation (rTMS), reflecting short-term plasticity, and paired associative stimulation (PAS), reflecting long-term plasticity, and were asked to focus their attention on the hand contralateral to the M1 stimulated. A group of age-matched healthy subjects acted as control. Results: In patients with MS, 5-Hz rTMS and PAS failed to induce the normal increase in motor-evoked potential (MEP). During the attention-demanding condition, 5-Hz rTMS- and PAS-induced responses differed in patients with MS with and without fatigue. Whereas in patients with fatigue neither technique induced the attention-induced MEP increase, in patients without fatigue they both increased the MEP response, although they did so less efficiently than in healthy subjects. Attention-induced changes in short-term cortical plasticity inversely correlated with fatigue severity. Conclusion: Short-term and long-term plasticity mechanisms are abnormal in MS possibly owing to widespread changes in ion-channel expression. Fatigue in MS reflects disrupted cortical attentional networks related to movement control.