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 .
Mitochondrial disease in adults: A scale to monitor progression and treatment
The natural history of mitochondrial diseases is poorly understood , limiting our ability to offer prognostic advice to patients or to evaluate therapy . One major obstacle to improving our underst and ing is the lack of a clinical rating scale to monitor the extensive clinical spectrum of mitochondrial disease . In this article , the authors describe the development and validation of a practical and semiquantitative rating scale , the Newcastle Mitochondrial Disease Adult Scale .
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 .