Muscle performance relates to physical function and quality of life in long-term chronic inflammatory demyelinating polyradiculoneuropathy

The aim of the present study was to determine the severity and distribution of assessed muscle weakness and to relate muscle performance to measures of function and quality of life in long-term chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Fourteen patients with 8.7 years (3.3-11.5) of confirmed CIDP consecutively referred to the referral center for CIDP patients at Aarhus University Hospital, Denmark, during the period 1992-2002 were compared with matched healthy controls. The main outcome parameter was muscle performance assessed with isokinetic dynamometry. Overall disability sum score (ODSS), neurological symptom score (NSS), neuropathy impairment score (NIS), health-related quality-of-life survey (SF-36), nerve conduction studies, physical fitness, hand and walking performance, and quantitative sensory testing were secondary variables. The mean (95% CI) isokinetic strength of all measured muscles was reduced by 19.4% (5.9-32.8%) (p < 0.01). In the legs, distal weakness was predominant, strength at ankle being 37.0% (14.7-59.2%) reduced. Isokinetic strength was closely related to manual muscle strength, ODSS, NIS, walking performance, and physical components of SF-36. In conclusion, isokinetic strength relates to measures of function, impairments, gait performance, and physical components of health-related quality of life in long-term CIDP. Furthermore, a detailed characterization of severity and distribution of weakness has been provided using this technique.