Funded By:
By D.D. Kilmer, R.T. Abresch, S.G. Aitkens, G.T. Carter,W.M.
Fowler, Jr.,
E.R. Johnson, C.M. McDonald, and and N.J. Wright.
RTC/Neuromuscular Diseases, Department of Physical Medicine & Rehabilitation, University of California, Davis, and NIDRR Grant H133B30026.
Facioscapulohumeral dystrophy (FSHD) is one of several disordersincluded in the facioscapulohumeral syndrome. This syndrome includes individuals with facial involvement in spinal muscular atrophy and congenital myopathy.FSHD can occur with or without inflammatory cells in the muscle (as in polymyositis) and some cases are associated with Coat's disease (deafness).
FSHD is a myopathy, usually slowly progressive, and inherited as adominant trait. It is a rare neuromuscular disease with anestimated prevalence between 10 to 20 cases per millionindividuals. While the characteristics are well known (weakness of the face, shoulder and hip girdle, and anterior compartmental muscles of the leg), description of these characteristics has been primarily based on clinical observations, and there have not been any studies using specific measurements to evaluate each characteristic in terms of a natural history profile. In addition, there have been few, if any, investigations of the incidence and description of some of the characteristics such as contractures, spine deformity, pulmonary and cardiac function, intellectual and cognitive function, and psychosocial adjustment.
The purpose of this study was to develop a comprehensive impairmentand disability profile for FSHD. Impairment was evaluated by measurements of strength, contractures, spine deformity, cardiac and pulmonary function, and intellectual capacity. Disability evaluations consisted of measures of mobility and upper extremity function, cardiac and pulmonary disease, and psychosocial adjustments.
Fifty-three individuals followed in a regional neuromusculardisease clinic, 1982-1992, were reviewed. Thirty-two were males and 21 were females. Average age was 38 years with an average age of symptom onset of 16 years at the time of the first clinic visit. Five individuals were nonambulatory, and age at loss of ambulationaveraged 33 years. Four were known to have died during the ten year period with a mean age of death at 68 years. All participants from the clinic did not receive all measurements so the individuals in each of the impairment and disability profiles would be considered as samples of the larger clinic population.
When appropriate, results were compared with able-bodied subjects(controls) and/or established reference standards. The effect of age and disease duration was evaluated by both one-time event (cross sectional) and longitudinal analysis. In the former, the first measurement obtained on every subject was plotted againstyears of age and disease duration. In the latter, each measurement for each individual for a three or more year period of time was analyzed for any age or disease duration effect.
Body Composition Profile: Anthropometric and body compositionmeasurements were obtained in a sample of 14 individuals. Anthropometric measures of height, bisacromial and biiliac diameters, wrist and ankle circumferences, and chest depth were within normal limits in the FSHD group when compared to gender and age matched control subjects and reference standards. Weight, and the circumferential diameter of the forearm were also within normal limits. The calf (-7%), thigh (-10%), and upper arm (-11%)circumferences were, however, significantly reduced in the FSHDgroup indicating mild loss of musculature. Body fat, as evaluated by skinfold thickness at five sites, was within normal limits. For all parameters, there was no significant age or disease duration effect indicating that muscle wasting was very slowly progressive.
Muscle Weakness Profile: Muscle strength was evaluated by bothmanual muscle testing (MMT) units and quantitative measurements of strength.
MMTs: MMTs were obtained in a sample of 22 individuals. Gradingwas on a 0-5 scale, in which 5 is normal, for 34 muscle groups. The total strength grade for all muscle groups combined was 3.7 MMT units (complete range of motion against gravity plus minimal resistance from the therapist.) In cross-sectional one-time event analysis, there was a very slow but significant rate of decline in mean total strength of -0.022 MMT units per year of disease duration.Average grades for clusters of muscle groups showed that the lowerextremity muscles were weaker than the upper extremity muscles, the proximal muscles weaker than the distal muscles, extensor muscles weaker than flexor muscles, and the ankle dorsiflexors weaker than the plantar flexors. In general, the rate of strength decline was more rapid in the weaker muscle groups of the lower extremities.
