title: Differences in F-Wave Characteristics between Spinobulbar Muscular Atrophy and Amyotrophic Lateral Sclerosis.
abstract: There is limited data on the differences in F-wave characteristics between spinobulbar muscular atrophy (SBMA) and lower motor neuron dominant (LMND) amyotrophic lateral sclerosis (ALS). We compared the parameters of F-waves recorded bilaterally from the median, ulnar, tibial, and deep peroneal nerves in 32 SBMA patients, 37 patients with LMND ALS, and 30 normal controls. The maximum F-wave amplitudes, frequencies of giant F-waves, and frequencies of patients with giant F-waves in all nerves examined were significantly higher in the SBMA patients than in the ALS patients and the normal controls. The mean F-wave amplitude, maximum F-wave amplitude, frequency of giant F-waves, and frequency of patients with giant F-waves in the median and deep peroneal nerves were comparable between the ALS patients and normal controls. Giant F-waves were detected in multiple nerves and were often symmetrical in the SBMA patients compared with the ALS patients. The number of nerves with giant F-waves seems to be the most robust variable for differentiation of SBMA from ALS, with an area under the curve of 0.908 (95% CI: 0.835-0.982). A cut-off value of the number of nerves with giant F-waves (≥3) for diagnosing SBMA showed high sensitivity and specificity: 85% sensitivity and 81% specificity vs. ALS patients. No significant correlations were found between the pooled frequency of giant F-waves and disease duration in the SBMA (r = 0.162, P = 0.418) or ALS groups (r = 0.107, P = 0.529). Our findings suggested that F-waves might be used to discriminate SBMA from ALS, even at early stages of disease.
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical CollegeBeijing, China; Neuroscience Center, Chinese Academy of Medical SciencesBeijing, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Cui
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Yuzhou
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Cui
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Dongchao
authors.initials: D
authors.lastname: Shen
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing, China.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Ding
keywords: F-wave; amyotrophic lateral sclerosis; giant F-wave; motor neuron; nerve conduction study; spinobulbar muscular atrophy