RESULTS We found that none of the 19 instruments have sufficiently comprehensive reporting of measurement or feasibility performance as would be required by regulatory authorities .
INTRODUCTION In an accompanying study we reported on the content of several activity rating scales that have been used for muscle disease .
To further aid in achieving consensus we conducted a systematic review to assess the quality of the 19 activity rating scales  design ed specifically for muscle disease .
Indicators of need for mechanical ventilation in Duchenne muscular dystrophy and spinal muscular atrophy.
STUDY OBJECTIVES The purpose was to investigate a possible relationship between different parameters of physical function , spirometric measurements , and the approaching need for mechanical ventilation . DESIGN A nonr and omized , prospect i ve , descriptive study of 11 patients with spinal muscular atrophy type II ( SMA-II ) and 14 patients with Duchenne muscular dystrophy ( DMD ) . At a home visit , the anthropometric indices of age , height , and weight were recorded , the degree of disability was scored , and measurement of the strength of eight muscle groups and spirometry was performed . The interdependence of the variables was analyzed and the intergroup differences evaluated . Eighteen months later , it was found that one of the authors ( B.J. ) , who was blind to the results of the first examination had instituted home mechanical ventilation on seven of the patients . The data were analyzed retrospectively for their predictive value as indicators of approaching ventilator dependency . RESULTS The seven patients who needed mechanical ventilation were the patients with DMD with the highest disability score ( Egen Klassifikation [ EK ] sum > 20 ) and the smallest values for FVC < 1.2 L ( FVC% < 30 ) . We found a significant correlation ( p = 0.002 ) between FVC% and the EK sum at the first examination and between the FVC% and the time until treatment with mechanical ventilation  was instituted ( p = 0.023 ) . Although 7 of the 11 patients with SMA type II had FVC below 1.2 L and some of them had an EK sum score higher ( indicating more disability ) than some patients with DMD who needed mechanical ventilation , none of them required mechanical ventilation . CONCLUSION In this investigation , a combination of EK sum and FVC% provided a better indication of the approaching need for mechanical ventilation in the patients with DMD than the variables separately
RESULTS We found that none of the 19 instruments have sufficiently comprehensive reporting of measurement or feasibility performance as would be required by regulatory authorities .
INTRODUCTION In an accompanying study we reported on the content of several activity rating scales that have been used for muscle disease .
To further aid in achieving consensus we conducted a systematic review to assess the quality of the 19 activity rating scales  design ed specifically for muscle disease .