Data from: Intra-Rater reliability and validity of outcome measures in Myotonic Dystrophy Type 1

Objective To investigate intra-rater reliability, concurrent- and
construct validity of muscle strength, balance, and functional mobility
measures in individuals with non-congenital DM1. Methods Seventy-eight
adults with non-congenital DM1 participated in visit 1 and 73 of the
subjects participated in visit 2 separated by 1-2 weeks. The assessments
consisted of muscle strength tests with Hand-Held Dynamometry (HHD) and
Stationary Dynamometry in the lower limb. The balance tests comprised of
Step Test, Timed Up and Go test, Feet-Together stance, Tandem-Stance,
One-Leg-Stance, and modified Clinical Test of Sensory Integration and
Balance on a balance platform. The functional mobility tests consisted of
the 10-meter Walk Test (10mWT) and 10-times Sit-To-Stand test. Results The
HHD and Stationary Dynamometry were sufficiently intra-rater reliable for
most muscle groups on a group- (SEM%≤15%) and individual level
(MDD95%≤30%), but HHD was most reliable. Stationary Dynamometry measured a
higher torque than HHD for all extensor muscles, but for single
individuals none of the devices were favored. Overall, intra-rater
reliability and validity were only sufficient for the dynamic balance
tests and not the static balance tests. Both functional mobility tests
were sufficiently reliable and valid, but the 10mWT was most reliable.
Conclusion Overall, HHD is recommended as a reliable and valid tool for
single individuals and for flexor muscles on a group level. For balance
assessments, the dynamic balance tests are recommended as the most valid
and reliable balance tests. Both functional mobility tests are recommended
for valid and reliable outcomes, but the 10mWT was superior for
reliability.