Yuzhou Guan

F Wave Study in Amyotrophic Lateral Sclerosis: Assessment of Segmental Motoneuronal Dysfunction.

Background: Dysfunctional spinal circuit may play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). The purpose of this study was to use F waves for assessment of segmental motoneuronal excitability following upper motor neuron (UMN) dysfunctions in ALS. Methods: We studied the F waves of 152 ulnar nerves recorded from abductor digiti minimi in 82 patients with ALS. Two groups of hands were defined based on the presence or absence of pyramidal signs in the same upper limb. The group with pyramidal signs in the upper limbs was designated as the P group, and the group without pyramidal signs in the upper limbs was designated as the NP group. Results: The mean (P < 0.001), median (P < 0.001) and maximum (P = 0.035) F wave amplitudes, mean (P < 0.001), median (P < 0.001) and maximum (P = 0.003) F/M amplitude ratio, index repeating neuron (P < 0.001) and index repeater F waves (P < 0.001) of the P group were significantly increased compared with the NP group. No significant differences were identified for F wave chronodispersion (P = 0.628), mean F wave latency (P = 0.151), minimum F wave latency (P = 0.211), maximum F wave latency (P = 0.199), F wave persistence (P = 0.738), F wave duration (P = 0.152), F wave conduction velocity (P = 0.813) and number of giant F waves (P = 0.072) between the two groups. Conclusions: In this study, increased F wave amplitude, F/M amplitude ratio and number of repeater F waves reflected enhanced segmental motoneuronal excitability following UMN dysfunctions in ALS.

Motor nerve conduction study and muscle strength in newly diagnosed POEMS syndrome.

Introduction: Mixed demyelination and axonal loss are electrophysiological features of polyneuropathy, organomegaly, endocrinopathy, M‐protein, and skin changes (POEMS) syndrome. It is unclear whether the demyelination and axonal loss occur concurrently. Methods: Electromyography was performed in 37 patients with newly diagnosed POEMS syndrome. Compound muscle action potential (CMAP) amplitude, distal motor latency, motor conduction velocity (MCV), and spontaneous activity were collected. Muscle strength was measured according to the Medical Research Council (MRC) scale. Results: MCV decreased in all nerves with decreased CMAP amplitude and in 93% of nerves with normal amplitude. CMAP amplitude decreased in 54% of nerves with decreased MCV and was normal in all nerves with normal MCV. MCV deceased in 95% of nerves with normal MRC. Abnormal spontaneous activity was detected in 32% of upper limb muscles. Conclusions: Demyelination may be the main manifestation in POEMS neuropathy at an early stage, and axonal loss may be secondary to demyelination as the disease progresses. Muscle Nerve 51: 19–23, 2015

Single-fiber electromyography in amyotrophic lateral sclerosis and cervical spondylosis

Cervical spondylosis (CS) is a common disease in adults and may coexist with amyotrophic lateral sclerosis (ALS). It is important to detect ALS coexisting with CS (ALS‐cs) at an early stage, especially when surgical treatment of CS is planned.

Importance of Sample Size for the Estimation of Repeater F Waves in Amyotrophic Lateral Sclerosis

Background:In amyotrophic lateral sclerosis (ALS), repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size. Methods:We studied the F waves of left ulnar nerves in ALS patients. Based on the presence or absence of pyramidal signs in the left upper limb, the ALS patients were divided into two groups: One group with pyramidal signs designated as P group and the other without pyramidal signs designated as NP group. The Index repeating neurons (RN) and Index repeater F waves (Freps) were compared among the P, NP and control groups following 20 and 100 stimuli respectively. For each group, the Index RN and Index Freps obtained from 20 and 100 stimuli were compared. Results:In the P group, the Index RN (P = 0.004) and Index Freps (P = 0.001) obtained from 100 stimuli were significantly higher than from 20 stimuli. For F waves obtained from 20 stimuli, no significant differences were identified between the P and NP groups for Index RN (P = 0.052) and Index Freps (P = 0.079); The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the control group; The Index RN (P = 0.002) of the NP group was significantly higher than the control group. For F waves obtained from 100 stimuli, the Index RN (P < 0.001) and Index Freps (P < 0.001) of the P group were significantly higher than the NP group; The Index RN (P < 0.001) and Index Freps (P < 0.001) of the P and NP groups were significantly higher than the control group. Conclusions:Increased repeater F waves reflect increased excitability of motor neuron pool and indicate upper motor neuron dysfunction in ALS. For an accurate evaluation of repeater F waves in ALS patients especially those with moderate to severe muscle atrophy, 100 stimuli would be required.

Excessive daytime sleepiness in Chinese patients with sporadic amyotrophic lateral sclerosis and its association with cognitive and behavioural impairments

Objective To examine the frequency and clinical features of excessive daytime sleepiness (EDS) and its association with cognitive and behavioural impairments in patients with amyotrophic lateral sclerosis (ALS). Methods We conducted a cross-sectional investigation to explore the frequency and clinical features of EDS in a group of 121 Chinese patients with ALS compared with 121 age-matched and sex-matched healthy subjects. EDS was diagnosed using the Epworth Sleepiness Scale (ESS). Other characteristics of patients with ALS including sleep quality, REM sleep behaviour disorder (RBD), restless legs syndrome (RLS), cognition, behaviour, depression and anxiety were also evaluated. Results EDS was significantly more frequent in patients with ALS than in controls (26.4% vs 8.3%; p<0.05). Patients with ALS with EDS scored lower scores on the revised ALS Functional Rating Scale (ALSFRS-R), Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and MMSE and MoCA delayed memory subitems and higher on the Frontal Behavioural Inventory (FBI) than patients with ALS without EDS. ESS scores correlated with global ALSFRS-R, FBI, MMSE and MoCA scores and MMSE and MoCA delayed memory scores. RLS and global ALSFRS-R scores were independently associated with EDS in patients with ALS. Conclusions We identified a high frequency of EDS symptoms in Chinese patients with ALS, and these patients might have more serious physical, cognitive and frontal behaviour impairment. Patients with ALS might improve quality of life from the timely recognition and optimised management of EDS symptoms. Our results further suggest that ALS is a heterogeneous disease that might exhibit abnormal sleep-wake patterns.

Correlation of Creatine Kinase Levels with Clinical Features and Survival in Amyotrophic Lateral Sclerosis

Objective To evaluate serum creatine kinase (CK) levels of amyotrophic lateral sclerosis (ALS) patients and to explore the relationship between CK levels and the clinical characteristics and survival prognosis of ALS patients. Methods We analyzed the CK levels of 185 ALS patients who underwent long-term follow-up. The relationship between CK levels and clinical features including sex, age, disease duration, site of onset, body mass index (BMI), serum creatinine (Cr), and spontaneous electromyographic activity was analyzed by univariate analysis and multiple linear regression. Kaplan–Meier and Cox proportional hazards models were used to explore whether CK levels were independently correlated with survival prognosis of ALS. Results Baseline serum CK was raised in 43% of participants. The median CK level was 160 U/L (range: 20–2,574 U/L), and 99% of patients had a baseline serum CK level less than 1,000 U/L. CK levels were significantly higher in male patients than in female patients [204 (169) versus 117 (111) U/L, p < 0.001] and in patients with limb onset ALS than with bulbar onset ALS (p < 0.001). CK levels were also correlated with serum Cr (p = 0.011) and the spontaneous potential score of electromyography (EMG) (p = 0.037) but not correlated with age (p = 0.883), disease duration (p = 0.116), or BMI (p = 0.481). Log CK was independently correlated with survival of ALS patients (HR = 0.457, 95% confidence interval 0.221–0.947, p = 0.035) after adjusting for age, sex, site of onset, serum Cr, and BMI. Conclusion Serum CK levels of ALS patients were correlated with sex, site of onsite, serum Cr, and spontaneous activity in EMG. Serum CK could be an independent prognostic factor for survival of ALS patients.

Amyotrophic Lateral Sclerosis and Myasthenia Gravis Overlap Syndrome: A Review of Two Cases and the Associated Literature

Objective To describe the characteristics of patients with amyotrophic lateral sclerosis (ALS) and myasthenia gravis (MG) overlap syndrome and explore the relationship between the two diseases. Methods We conducted a search of medical records at Peking Union Medical University Hospital from 1983 to 2015 for coexistence of ALS and MG and searched the PubMed database for all literature describing ALS and MG overlap syndrome published through December 2016. We analyzed the clinical and neurophysiological characteristics of patients by groups according to strict diagnostic criteria. Results We presented 2 patients in our database with combined ALS and MG, and together with 25 cases reported in the literature, the patients were divided into 4 groups: 12 patients with MG followed by ALS, 8 patients with ALS followed by MG, 5 ALS patients with false-positive anti-acetylcholine receptor, and the other 2 ALS patients with only myasthenia symptoms. Most patients had limb onset ALS, and myasthenia symptoms mainly affected ocular and bulbar muscles. Clinical and neurophysiological characteristics were summarized. Conclusion These findings support the conclusion that immunological mechanisms and alterations in the neuromuscular junction are related to ALS pathogenesis.

Differences in F-Wave Characteristics between Spinobulbar Muscular Atrophy and Amyotrophic Lateral Sclerosis

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.

Quantitating Changes in Jitter and Spike Number Using Concentric Needle Electrodes in Amyotrophic Lateral Sclerosis Patients

Background:Single-fiber electromyography (SFEMG) has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis (ALS) by the revised EI Escorial criteria. Although concentric needle (CN) electrodes have been used to assess jitter in myasthenia gravis patients and healthy controls, there are few reports using CN electrodes to assess motor unit instability and denervation in neurogenic diseases. The aim of this study was to determine whether quantitative changes in jitter and spike number using CN electrodes could be used for ALS studies. Methods:Twenty-seven healthy controls and 23 ALS patients were studied using both CN and single-fiber needle (SFN) electrodes on the extensor digitorum communis muscle with an SFEMG program. The SFN-jitter and SFN-fiber density data were measured using SFN electrodes. The CN-jitter and spike number were measured using CN electrodes. Results:The mean CN-jitter was significantly increased in ALS patients (47.3 ± 17.0 &mgr;s) than in healthy controls (27.4 ± 3.3 &mgr;s) (P < 0.001). Besides, the mean spike number was significantly increased in ALS patients (2.5 ± 0.5) than in healthy controls (1.7 ± 0.3) (P < 0.001). The sensitivity and specificity in the diagnosis of ALS were 82.6% and 92.6% for CN-jitter (cut-off value: 32 &mgr;s), and 91.3% and 96.3% for the spike number (cut-off value: 2.0), respectively. There was no significant difference between the SFN-jitter and CN-jitter in ALS patients; meanwhile, there was no significant difference between the SFN-jitter and CN-jitter in healthy controls. Conclusion:CN-jitter and spike number could be used to quantitatively evaluate changes due to denervation-reinnervation in ALS.

Single-fiber Electromyography in the Extensor Digitorum Communis for the Predictive Prognosis of Ocular Myasthenia Gravis: A Retrospective Study of 102 Cases

Background: Single-fiber electromyography (SFEMG) abnormality in the extensor digitorum communis (EDC) was reported in ocular myasthenia gravis (OMG), which indicated subclinical involvement beyond extraocular muscles in OMG patients. The relationship between the abnormal findings of SFEMG in EDC and the probability for OMG to develop generalized myasthenia gravis (GMG) is unknown. This retrospective study aimed to determine the predictive value of abnormality of SFEMG in EDC of OMG patients. Methods: One-hundred and two OMG patients underwent standard clinical diagnosis process and SFEMG test in EDC muscle when diagnosed and were clinically followed up for 5 years. The SFEMG data were compared between different clinical groups according to thymus status, onset age, and different outcome of OMG developing. Chances of progressing to GMG were compared between two different groups according to SFEMG and repetitive nerve stimulation (RNS) results, acetylcholine receptor antibody (AchRAb) titer, thymus status, and onset age. Results: Abnormal SFEMG results were observed in 84 (82.4%) patients. The mean jitter, percentage of jitter >55 &mgr;s (%), and blocking were higher in OMG patients than in healthy volunteers. There were no statistical differences in jitter analysis between thymoma group and non-thymoma group (P = 0.65), or between the later OMG group and the later GMG group (P = 0.31), including mean jitter, percentage of jitter >55 &mgr;s (%), and blocking. Elderly group (≥45 years old) had a higher mean jitter than younger group (t = 2.235, P = 0.028). Total 55 OMG developed GMG, including 47 in abnormal SFEMG group while 8 in normal SFEMG group. There was no statistical difference in the conversion rates between the two groups (&khgr;2 = 0.790, P = 0.140). RNS abnormality, AchRab titer, or onset age had no correlation with OMG prognosis (P = 0.150, 0.070, 0.120, respectively) while thymoma did (&khgr;2 = 0.510, P = 0.020). Conclusion: SFEMG test in the EDC showed high abnormality in OMG, suggesting subclinical involvement other than extraocular muscles. Nevertheless, the abnormal jitter analysis did not predict the prognosis of OMG according to clinical follow-up.