Macro-EMG and MUNE Changes in Patients with Amyotrophic Lateral Sclerosis: One-Year Follow Up

ABSTRACT

Objective: We assessed changes in Motor Units (MU) and extent of MU loss using macro-electromyography (macro-EMG) and Motor Unit Number Estimation (MUNE). Methods: We applied these techniques to a sample of 61 Amyotrophic Lateral Sclerosis (ALS) patients basally (T0) and after 4 (T1), 8 (T2), and 12 (T3) months. Macro Motor Unit Potentials (macro-MUPs) were derived from Biceps Brachii (BB) muscle; MUNE was performed both in BB and Abductor Digiti Minimi (ADM) muscles of the same side. Results: Macro-MUPs area resulted in progressive increase at T1, T2, and T3 with respect to T0. Fiber density (FD) at T3 decreases a bit than at T2. Functioning MUS number decreased in both the muscles throughout the entire follow-up with respect to T0 and the rate of MU decrease was similar in both the muscles, but steeper distally. Conclusions and Significance: Macro-EMG increase and FD decrease suggest that a process of MU rearrangement begins to fall after 8 months of disease course. Combined use of macro-EMG and MUNE techniques in ALS patients allows to track over time changes in muscle MU features and number in face of progressive anterior horn cells death during disease's evolution.

KEYWORDS: :

• Amyotrophic lateral sclerosis
• macro-EMG
• MUNE
• time changes