A Belgian natural history study evaluated the sensitivity of walking tests, MRC score and isokinetic dynamometer in 24 walking patients with ANO5-related LGMD R12 over two years. These results are compared with quantitative MRI examination of the thigh muscles.
The investigators show that :
- Possible muscle changes in patients with early or late stage muscle degeneration are not detected over the two years of follow-up, regardless of the test method.
- The fat fraction measured by MRI of the muscles of patients who were enrolled in the study at an “intermediate” stage of the disease (fat replacement between 20% and 70%) shows a detectable increase one year after the start of the follow-up.
- Muscle strength measured by isokinetic dynamometer shows a decrease in the thighs one year after the start of follow-up, which makes it a good measurement tool for clinical trials.
- Walking tests and the MRC score do not detect any significant change in muscle function, even after two years of follow-up.
- Fat replacement in thigh muscles is not homogeneous within the same muscle, indicating the need to assess the whole muscle.
