Spinal muscular atrophy outcome measures

Editors-in-Chief: C. Michael Gibson, M.S., M.D.; Priyamvada Singh, MBBS

Overview
There is currently no cure for spinal muscular atrophy. There has been great interest in identifying agents that can increase the amount of full- length SMN protein by upregulating expression of the SMN2 gene. Many clinical trials are ongoing to find the most reliable outcome measures.

Several new outcome measures have shown encouraging results and helped in designing future clinical trials. Some of them currently used in clinical trials are as follows –
 * Quantitative muscle ultrasound
 * The Six-Minute Walk Test (6MWT) – In case of ambulatory SMA patients.


 * 10 minute walk/run test


 * The Hammersmith Motor Scale


 * The Hammersmith Functional Motor Scale Expanded (HFMSE)


 * Knee flexor strength test


 * The Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND)


 * The Gross Motor Function Measurement


 * Motor unit number estimation (MUNE)


 * Compound motor action potential (CMAP) amplitude


 * Serologic biomarkers (SMN mRNA and protein levels)