Inter-rater reliability of the Rasch-modified medical research council scoring criteria for manual muscle testing in neuromuscular diseases.

It was argued that researchers and clinicians are not able to make judgments between most categories of the original Medical Research Council (MRC) scale and that a modified short version would reach higher agreement levels. We aimed to assess the inter-rater reliability for both the original and the Rasch-modified MRC scoring criteria of Manual Muscle Strength tests (MMSt) in patients with neuromuscular diseases. Two MRC scoring criteria were used to score muscle strength using MMSt in 40 muscle groups of the upper and lower limbs in patients with neuromuscular disorders. Three investigators performed the evaluations; the order of the MMSt and the use of the scales were performed according to the preferences of the investigators. The agreement coefficient (Gwet's AC2 ) was used to compute the reliability. Sixty patients (mean age of 39.3 years ± 15.2) with neuromuscular diseases were included. The mean AC2 for the muscle groups of the upper limbs ranged from 0.82 to 0.96 using the modified MRC scale and from 0.86 to 0.96 using the original MRC scale. The AC2 for the lower limb muscle groups ranged from 0.80 to 0.91 (modified MRC scale) and from 0.87 to 0.93 (original MRC scale). These values might be interpreted as "almost perfect agreement" with no significant differences between the scales. The results indicate that both MRC scoring criteria have significant reliability among trained observers. Moreover, the Rasch-modified MRC scale is as reliable as the original MRC scale and can be used in future clinical studies.

Alternative instrument for the evaluation of handgrip strength in Duchenne muscular dystrophy.

BACKGROUND: The commonly used dynamometers can be ineffective in evaluating handgrip in patients with Duchenne muscular dystrophy (DMD), especially children with generalized muscle weakness. The aim of this study was to analyze whether the modified sphygmomanometer is an effective instrument for handgrip strength evaluation in patients with DMD, during different stages of the disease. METHOD: The handgrip strength of 33 patients was evaluated by the Jamar dynamometer and the modified sphygmomanometer. Motor function was evaluated by the Motor Function Measurement (MFM) scale. Four evaluations, with a six-month interval between each, were performed: Evaluation 1 (N = 33), Evaluation 2 (N = 24), Evaluation 3 (N = 15), and Evaluation 4 (N = 8). A linear regression model with mixed effects was used for the longitudinal data and descriptive analysis of strength for all four evaluations. RESULT: The first evaluation data presented very high correlations between the dynamometer and the modified sphygmomanometer (r = 0.977; p < 0.001). The longitudinal analysis showed a significant difference between Evaluation 1 and the other handgrip strength evaluations obtained using the dynamometer (p < 0.05) but not the modified sphygmomanometer (p > 0.05). Null values were obtained only when using the dynamometer device. CONCLUSION: The modified sphygmomanometer seems to be more suitable than the dynamometer for measuring handgrip strength in all stages of DMD.