Comparison between upper limb onset classic amyotrophic lateral sclerosis and flail-arm syndrome / 西安交通大学学报(医学版)

Objective: To investigate the clinical and electrophysiological characteristics of upper limb onset classic amyotrophic lateral sclerosis (ALS) and ALS variant flail-arm syndrome (FAS) so as to provide reference for differential diagnosis and prognosis. Methods: We recruited 120 upper limb onset classic ALS and 18 FAS patients from Neurology Department of The First Affiliated Hospital of Xi'an Jiaotong University between January 2013 and December 2018. The clinical and electrophysiological characteristics and survival were compared between the two groups. Results: Compared with those in upper limb onset classic ALS, FAS patients' diagnostic level was lower (P<0.001), diagnostic delay time was longer (15 mon vs. 11 mon; Z=-2.749, P=0.005), progression rate was slower (0.33 vs. 0.64; Z=-3.055, P=0.002), and time from the first region to the second was longer (33 mon vs. 8 mon; Z=-4.852, P<0.001). FAS patients were as likely to have single lateral upper limb onset as those with upper limb onset classic ALS, but the proportion of patients with bilateral upper limbs onset in FAS group was higher than that in the upper limb onset classic ALS group (33.3% vs. 8.3%; χ2=7.261, P=0.007), the proportion of proximal upper limb being more severely affected was higher in FAS group (55.6% vs. 18.3%; χ2=8.856, P=0.003). The proportion of FAS patients with high upper limb reflex or pathologic sign was lower (11.1% vs. 72.5%; χ2=25.759, P<0.001). Compared with upper limb onset classic ALS, FAS group's ratio of compound muscle action potential (CMAP)abductor pollicis brevis/CMAPabductor digiti minimi was higher, but without statistical significance; needle electrode electromyographic results were similar between the two groups. Survival time of FAS patients was longer than that of patients with upper limb onset classic ALS (53 mon vs. 22 mon; Z=-4.421, P<0.001), and FAS diagnosis itself was an independent prognostic factor of lower death risk compared with the diagnosis of upper limb onset classic ALS (HR=0.174, 95% CI: 0.061-0.496, P=0.001). Conclusion: Although natural histories of FAS and upper limb onset classic ALS are different, their EMG performance is similar. Characteristics including bilateral arms onset, proximal symptoms being severer than distal ones, lower motor neuron findings being more prominent have some implications for diagnosis of FAS.

Electrophysiological characteristics of the split hand syndrome in amyotrophic lateral sclerosis and the variant / 中华神经科杂志

Objective To study the electrophysiological characteristics of hands muscle of upper limb onset amyotrophic lateral sclerosis (UL-ALS), and the variant-flail arm syndrome (FAS) for diagnosis and differential diagnosis. Methods We chose 55 UL-ALS and 12 FAS patients as the cases, 20 cervical spondylotic amyotrophy (CSA) patients as the case controls, and 20 healthy volunteers as the normal controls from January 2013 to March 2018 in the Third Central Hospital of Tianjin. Conventional nerve conduction studies of the median nerve and ulnar nerve were performed in all the patients. The main analysis was done in the compound muscle action potential (CMAP) recorded on the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) and the ratio of the two. Results The ratio of CMAPAPB/CMAPADM of ALS was 0.59 (0.25, 0.79), which was depressed obviously compared with FAS (1.02 (0.92, 1.18), Z=-4.440, P=0.000), CSA (1.88 (1.42, 3.19), Z=-5.902,P=0.000) and the normal controls (0.96 (0.88, 1.15), Z=-5.416, P=0.000). The low ratio of CMAPAPB/CMAPADM (<0.6) was encountered in 40％(23/55) ALS patients, 0 CSA patient and 1/12 FAS patients. An absent APB CMAP and an abnormally low APB/ADM CMAP amplitude ratio (<0.25) were observed only in 25.4％ (14/55) ALS patients. The area under receiver operating characteristic curve in patients of UL-ALS was 0.911 (P=0.000), and in FAS was 0.518 (P=0.559). Using a cut-off value of CMAPAPB/CMAPADM=0.7 for diagnosing ALS yielded 85.5％sensitivity and 95.0％specificity. Conclusion The split hand syndrome is not specific for ALS; however, the low APB/ADM CMAP amplitude ratio may help predict prognosis and can be the diagnostic marker for ALS.

Surgical Treatment in Cervical Myelopathy Combined with Flail Arm Syndrome / 계명의대학술지

Flail arm syndrome (FAS) is a variant of the amyotrophic lateral sclerosis also known as Lou Gehrig's disease. FAS is a kind of motor neuron disease that represents a bilateral proximal muscle wasting of upper extremities. Degenerative cervical spondylosis is a common cause of cervical myelopathy and radiculopathy. The coexistence of cervical spondylosis and motor neuron disease can cause difficulties in diagnosis and treatment. This case is a cervical spondylotic myelopathy associated with FAS who had undergone surgical treatment. After the operation, subjective symptoms of the patient was more aggravated and it may be owing to natural history of FAS. The surgical treatment must be made very carefully in cervical spondylotic myelopathy patient combined with motor neuron disease.

Ventilation function disorder of flail arm syndrome / 中华内科杂志

Objective To study the features of ventilation function in patients with flail arm syndrome (FAS).Methods The clinical data of 351 patients with sporadic amyotrophic lateral sclcrosis (ALS) fron 2009 to 2013 were retrospectively reviewed.Among them,329 were classical ALS and 22 were FAS.The differences of forced vital capacity (FVC) between FAS and classical ALS were analyzed.Results The percent predicted FVC (FVC％pred) values were (88.0 ±9.5)％ in FAS and (84.3 ± 16.8)％ in classical ALS including 4 and 128 patients with abnormal FVC％ pred (＜80％) in FAS and classical ALS,respectively.The FVC％ pred levels were significantly higher in FAS subjects [(88.0 ± 9.5) ％] than in classical ALS subjects of bulb [(80.0 ± 14.8) ％] or those of upper limb [(80.8 ± 16.0) ％] onset with duration over 12 months (All P ＜ 0.05).The proportion of subjects with FVC％pred ＜ 80％ was statistically lower in FAS [18.2％ (4/22)] than in both classical ALS of upper limb onset [42.8％ (80/187);P=0.037] and classical ALS with duration over one year [48.5％ (48/99);P =0.009].Conclusions Impaired ventilation function occurs less and later in FAS than that in classical ALS of upper limb onset with duration over one year,suggesting later and less requirement for non-invasive positive pressure ventilation treatment for FAS patients.Differentiation of FAS subjects from ALS helps assess prognosis and make treatment plan for these patients.

Comparison between Flail Arm Syndrome and Upper Limb Onset Amyotrophic Lateral Sclerosis: Clinical Features and Electromyographic Findings

Flail arm syndrome (FAS), an atypical presentation of amyotrophic lateral sclerosis (ALS), is characterized by progressive, predominantly proximal, weakness of upper limbs, without involvement of the lower limb, bulbar, or respiratory muscles. When encountering a patient who presents with this symptomatic profile, possible diagnoses include upper limb onset ALS (UL-ALS), and FAS. The lack of information regarding FAS may make differential diagnosis between FAS and UL-ALS difficult in clinical settings. The aim of this study was to compare clinical and electromyographic findings from patients diagnosed with FAS with those from patients diagnosed with UL-ALS. To accomplish this, 18 patients with FAS and 56 patients with UL-ALS were examined. Significant differences were observed between the 2 groups pertaining to the rate of fasciculation, patterns of predominantly affected muscles, and the Medical Research Council scale of the weakest muscle. The presence of upper motor neuron signs and lower motor neuron involvement evidenced through electromyography showed no significant between-group differences.