The value of neurophysiological index in evaluating the progression of amyotrophic lateral sclerosis

Abstract

Objective To evaluate the value of neurophysiological index (NI) in evaluating the rate of progression of amyotrophic lateral sclerosis (ALS). Methods Forty-eight patients with ALS were enrolled in Zhongda Hospital of Southeast University from January 2010 to August 2016, of whom 36 patients met the ALS definite diagnostic criteria, 12 patients met the ALS probable diagnostic criteria (following study confirmed those patients met the ALS definite diagnostic criteria), including 8 bulbar-onset and 40 upper extremity onset forms of the disease. Fifty-four age- and sex-matched healthy subjects served as controls. After evaluated by the ALS Functional Rating Scale-revised (ALSFRS-R), all subjects underwent electrophysiological examination in the Electromyography Lab of the hospital. The rate of disease progression (ΔFS) =48-total ALSFRS-R score at initial visit/symptom duration (months). The relevance between the complex muscle action potential (CMAP), F frequency, distal motor latency (DML), NI and the ΔFS was investigated respectively. Results In ALS group, the ALSFRS-R score was 14.56±10.10, the duration from onset to diagnosis was (14.56±10.10) months, and the ΔFS was 1.54±1.18 per month. The median nerve NI in ALS group was 0.60±0.76, in control group was 2.56±0.78, with statistically significant difference between two groups (t=-12.5, P<0.01). The ulnar nerve NI in ALS group was 0.70±0.55, in control group was 0.96±0.10, also with statistically significant difference between two groups (t=-0.31, P=0.003). The median nerve NI and ulnar nerve NI both were negatively correlated with ΔFS (r=-0.63, P=0.000; r=-0.506, P=0.007). The ΔFS was exponentially based on median nerve NI (R2=0.668, P<0.01). Conclusion NI is an objective electrophysiological index, which could be used to evaluate the rate of disease progression in ALS, and to evaluate the prognosis of the disease. Key words: Amyotrophic lateral sclerosis; Nerve conduction; Neurophysiological index; Prognosis