F46. Rostral to caudal spreading patterns of clinical and electrophysiological features in amyotrophic lateral sclerosis with bulbar-onset

Abstract

Introduction The region of onset and speed of progression in amyotrophic lateral sclerosis (ALS) are subtype-related and highly variable. The present study was to explore the spreading pattern of clinical and electrophysiological features in amyotrophic lateral sclerosis with bulbar-onset (BO-ALS), a special subtype of ALS with more rapid progression and poorer prognosis than ALS with initial limb-onset. Methods We retrospectively reviewed the clinical and electrophysiological data of 42 consecutive in-patients with BO-ALS from 2009 to 2016, and then diagnostic latency (within 6 months or not) was used to group the patients for comparison of data. Results The distribution of weakness, fasciculation, and amyotrophy was significantly different in muscles innervated by bulbar and spinal segments, with the highest involvement in bulbar segment, followed by that in cervical and then in lumbosacral segment. Likewise, the distribution of abnormal muscle spontaneous activity and neurogenic MUPs detected in electromyography was also found in similar gradients from bulbar, cervical, and thoracic to lumbosacral segment. Meanwhile, significantly lower incidence of electrophysiological involvement in lumbosacral segment was observed in patients with shorter diagnostic latency (within 6 months from the onset). In addition, with more frequent finding of widespread neurogenic abnormalities in electromyography, younger patients were easier to receive a definite diagnosis. Conclusion Our study revealed a rostral-caudal spreading pattern of lower motor unit involvement in BO-ALS, which would help guide the early diagnosis of BO-ALS and make detailed care plans for the patients.