title: Is overwork weakness relevant in Charcot-Marie-Tooth disease?
abstract: BACKGROUND
  In overwork weakness (OW), muscles are increasingly weakened by exercise, work or daily activities. Although it is a well-established phenomenon in several neuromuscular disorders, it is debated whether it occurs in Charcot-Marie-Tooth disease (CMT). Dominant limb muscles undergo a heavier overload than non-dominant and therefore if OW occurs we would expect them to become weaker. Four previous studies, comparing dominant and non-dominant hand strength in CMT series employing manual testing or myometry, gave contradictory results. Moreover, none of them examined the behaviour of lower limb muscles.
  
  
  METHODS
  We tested the OW hypothesis in 271 CMT1A adult patients by comparing bilateral intrinsic hand and leg muscle strength with manual testing as well as manual dexterity.
  
  
  RESULTS
  We found no significant difference between sides for the strength of first dorsal interosseous, abductor pollicis brevis, anterior tibialis and triceps surae. Dominant side muscles did not become weaker than non-dominant with increasing age and disease severity (assessed with the CMT Neuropathy Score); in fact, the dominant triceps surae was slightly stronger than the non-dominant with increasing age and disease severity.
  
  
  CONCLUSIONS
  Our data does not support the OW hypothesis and the consequent harmful effect of exercise in patients with CMT1A. Physical activity should be encouraged, and rehabilitation remains the most effective treatment for CMT patients.
authors.affiliation: IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Piscosquito
authors.affiliation: MRC Centre for Neuromuscular diseases, UCL Institute of Neurology, London, UK.
authors.forename: M M
authors.initials: MM
authors.lastname: Reilly
authors.affiliation: Department of Neurology, Ophthalmology and Genetics, University of Genoa, Genoa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Schenone
authors.affiliation: Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Verona, Italy.
authors.forename: G M
authors.initials: GM
authors.lastname: Fabrizi
authors.affiliation: Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Verona, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Cavallaro
authors.affiliation: Federico II University Department of Neurological Sciences, Naples, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Santoro
authors.affiliation: Department of Neurosciences, University of Messina, and Clinical Centre NEMO SUD, Fondazione Aurora Onlus, Messina, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Vita
authors.affiliation: Neurology Clinic, Magna Graecia University, and Neuroimaging Research Unit, National Research Council, Catanzaro, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Quattrone
authors.affiliation: Department of Neurosciences, Catholic University and Don Gnocchi Foundation, Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Padua
authors.affiliation: Department of Neurosciences, University of Parma, Parma, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Gemignani
authors.affiliation: Department of Pharmacological Sciences, University School of Pharmacy, Milan, Italy IMDEA-Food, Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Visioli
authors.affiliation: MRC Centre for Neuromuscular diseases, UCL Institute of Neurology, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Laurà
authors.affiliation: IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Calabrese
authors.affiliation: MRC Centre for Neuromuscular diseases, UCL Institute of Neurology, London, UK.
authors.forename: R A C
authors.initials: RA
authors.lastname: Hughes
authors.affiliation: Department of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Radice
authors.affiliation: IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Solari
authors.affiliation: IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Pareyson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002607:Charcot-Marie-Tooth Disease / Q000150:complications* / Q000503:physiopathology; D012090:Cumulative Trauma Disorders / Q000209:etiology / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018908:Muscle Weakness / Q000209:etiology* / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology; D055815:Young Adult
keywords: CLINICAL NEUROLOGY; HMSN (CHARCOT-MARIE-TOOTH); NEUROGENETICS; NEUROPATHY; REHABILITATION