Relationships between impairment and disability in patients with neuromuscular disease

The intention of this study was to determine the relationship between impairment of the legs and disability in patients with neuromuscular disease. Impairment was assessed by measuring muscle strength with an isokinetic dynamometer (Cybex II) and by measuring reaction time and movement time. Disability was indexed by assessing functional abilities by means of a rating scale originally developed for patients with amyotrophic lateral sclerosis (ALS) and actual performance by means of the Sickness Impact Profile (SIP). Fourteen patients with neuromuscular disease and fourteen matched controls (matched on sex, age, weight and height) were studied. The results showed strong relationships between impairment and disability. Having established these relations, future research will be directed at demonstrating a causal relationship between impairment and disability.