title: Motor function-muscle strength relationship in spinal muscular atrophy.
abstract: The relationship between motor function and muscle strength in patients with spinal muscular atrophy (SMA) is still controversial. In 120 genetically proven SMA patients, aged 5 years or older, we measured muscle strength in the arms and legs by a hand-held dynamometer, forced vital capacity by a spirometer, and the time needed to walk 10 m, arise from the floor, and climb steps. SMA patients had markedly reduced muscle strength, approximating 20% of that predicted from age- and gender-matched normative data. Knee extensors were the weakest muscles in SMA patients. The young ambulant SMA patients performed better than adults in all the timed tests and had greater muscle strength on knee extension. This study shows a good relationship between motor ability and muscle strength in SMA and confirms that age-related loss of function in SMA is due to loss of muscle strength.
authors.affiliation: Neuromuscular Unit, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136 Bologna, Italy. merlini@ior.it
authors.forename: Luciano
authors.initials: L
authors.lastname: Merlini
authors.forename: Enrico
authors.initials: E
authors.lastname: Bertini
authors.forename: Carlo
authors.initials: C
authors.lastname: Minetti
authors.forename: Tiziana
authors.initials: T
authors.lastname: Mongini
authors.forename: Lucia
authors.initials: L
authors.lastname: Morandi
authors.forename: Corrado
authors.initials: C
authors.lastname: Angelini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vita
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004550:Elbow / Q000503:physiopathology; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology*; D020966:Muscular Disorders, Atrophic / Q000503:physiopathology*; D011446:Prospective Studies; D012727:Sex Characteristics; D016138:Walking / Q000502:physiology