Whole-body fasciculation detection in amyotrophic lateral sclerosis using motor unit MRI.

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 cmminvs. 0.04 ± 0.10 cmmin, p = 0.004), paraspinals (1.14 ± 1.61 cmminvs. 0.02 ± 0.02 cmmin, p = 0.016) and lower legs (1.42 ± 1.27 cmminvs. 0.13 ± 0.10 cmmin, p = 0.004), but not tongue (1.41 ± 1.94 cmminvs. 0.18 ± 0.18 cmmin, 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.