Whole-body fasciculation detection in amyotrophic lateral sclerosis using motor unit MRI (MUMRI)

Objective Compare fasciculation rates between amyotrophic lateral sclerosis (ALS) patients and healthy controls in body regions relevant for diagnosing ALS using motor unit MRI (MUMRI) at baseline and 6 months follow-up, and relate this to single-channel surface EMG (SEMG). Methods Tongue, biceps brachii, paraspinals and lower legs were assessed with MUMRI and biceps brachii and soleus with SEMG in 10 healthy controls and 10 patients (9 typical ALS, 1 primary lateral sclerosis [PLS]). Results MUMRI-detected fasciculation rates in typical ALS patients were higher compared to healthy controls for biceps brachii (2.40±1.90 cm-3min-1 vs. 0.04±0.10 cm-3min-1, p=0.004), paraspinals (1.14±1.61 cm-3min-1 vs. 0.02±0.02 cm-3min-1, p=0.016) and lower legs (1.42±1.27 cm-3min-1 vs. 0.13±0.10 cm-3min-1, p=0.004), but not tongue (1.41±1.94 cm-3min-1 vs. 0.18±0.18 cm-3min-1, p=0.556). The PLS patient showed no fasciculation. At baseline, 6/9 ALS patients had increased fasciculation rates compared to healthy controls in at least 2 body regions. At follow-up every patient had increased fasciculation rates in at least 2 body regions. The MUMRI-detected fasciculation rate correlated with SEMG-detected fasciculation rates (τ=0.475, p=0.006). Conclusion MUMRI can non-invasively image fasciculation in multiple body regions and appears sensitive to disease progression in individual patients. Significance MUMRI has potential as diagnostic tool for ALS.