Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Amyotrophic lateral sclerosis (ALS) and some mimic disorders, such as distal-type cervical spondylotic amyotrophy (CSA), Hirayama disease (HD), and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy. This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders.</p><p><b>METHODS</b>We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients, 95 patients with distal-type CSA, 88 HD patients, 43 SBMA patients, and 150 normal controls.</p><p><b>RESULTS</b>The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P < 0.001) than that in the normal controls. The ADM/APB CMAP amplitude ratio was significantly reduced in the patients with distal-type CSA (P < 0.001) and the HD patients (P < 0.001) compared with that in the normal controls. The patients with distal-type CSA had significantly lower APB CMAP amplitude than the HD patients (P = 0.004). The ADM/APB CMAP amplitude ratio was significantly lower in the HD patients (P < 0.001) than that in the patients with distal-type CSA. The ADM/APB CMAP amplitude ratio of the SBMA patients was similar to that of the normal controls (P = 0.862). An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (≥4.5) were observed exclusively in the ALS patients.</p><p><b>CONCLUSIONS</b>The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders.</p>

Quantitating Changes in Jitter and Spike Number Using Concentric Needle Electrodes in Amyotrophic Lateral Sclerosis Patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>The mean CN-jitter was significantly increased in ALS patients (47.3 ± 17.0 μs) than in healthy controls (27.4 ± 3.3 μs) (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 μs), 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.</p><p><b>CONCLUSION</b>CN-jitter and spike number could be used to quantitatively evaluate changes due to denervation-reinnervation in ALS.</p>

Single-fiber Electromyography in the Extensor Digitorum Communis for the Predictive Prognosis of Ocular Myasthenia Gravis: A Retrospective Study of 102 Cases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>Abnormal SFEMG results were observed in 84 (82.4%) patients. The mean jitter, percentage of jitter >55 μs (%), 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 μs (%), 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 (χ2 = 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 (χ2 = 0.510, P = 0.020).</p><p><b>CONCLUSION</b>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.</p>

F Wave Study in Amyotrophic Lateral Sclerosis: Assessment of Segmental Motoneuronal Dysfunction / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Importance of sample size for the estimation of repeater F waves in amyotrophic lateral sclerosis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>In amyotrophic lateral sclerosis (ALS), repeater F waves are increased. Accurate assessment of repeater F waves requires an adequate sample size.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Asynchronization in Changes of Electrophysiology and Pathology of Spinal Cord Motor Neurons in Rats Following Middle Cerebral Artery Occlusion / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Motor dysfunction is common in stroke patients. Clinical electrophysiological studies suggest that transsynaptic degeneration occurred in the lower motor neurons, while pathological evidence is lacked. This study aimed to combine the electrophysiological and pathological results to prove the existence of transsynaptic degeneration in the motor system after stroke.</p><p><b>METHODS</b>Modified neurologic severity score, electrophysiological, and pathological assessments were evaluated in rats before middle cerebral artery occlusion (MCAO), and at 24 hours, 7 days, and 14 days after MCAO. Paired and independent-sample t-tests were applied to assess the changes of electrophysiological and pathological data.</p><p><b>RESULTS</b>Compound motor action potential amplitude in the paretic side was significantly lower than the nonparetic side at both 24 hours (61.9 ± 10.4 vs. 66.6 ± 8.9, P < 0.05) and 7 days (60.9 ± 8.4 vs. 67.3 ± 9.6, P < 0.05) after MCAO. Motor unit number estimation of the paretic side was significantly less than the nonparetic side (379.0 ± 84.6 vs. 445.0 ± 89.5, P < 0.05) at 7 days after MCAO. Until 14 days after stroke, the pathological loss of motor neurons was detected. Motor neurons in 14-day MCAO group were significantly decreased, compared with control group (5.3 ± 0.7 vs. 7.3 ± 1.8, P < 0.05).</p><p><b>CONCLUSIONS</b>Both electrophysiological and pathological studies showed transsynaptic degeneration after stroke. This study identified the asynchronization in changes of electrophysiology and pathology. The abnormal physiological changes and function impairment can be detected in the early stage and recovered quickly, while the pathological loss of motor neuron can be detected only in a later stage.</p>

A clinical neurophysiology study of Hirayama disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hirayama disease is a rare disease characterized by juvenile-onset of asymmetric amyotrophy, of which etiology has not been clarified. The aim of our study was to investigate the clinical and neurophysiologic characteristics of Hirayama disease.</p><p><b>METHODS</b>Neurophysiological tests, including nerve conduction studies (NCS), F-wave and routine electromyography (EMG), were performed in seventy-three patients with Hirayama disease. EMG was selectively performed on upper and lower extremities, sternocleidomast and thoracic paravertebral muscles according to the clinical features of the patients.</p><p><b>RESULTS</b>Abnormal NCS parameters, including decreased compound muscle action potentials or delayed distal motor latency, were found in 34.2% (25/73) and 12.3% (9/73) of the patients, respectively. A total of 24.6% (18/73) of the patients showed decreased F-wave frequency. EMG demonstrated the presence of neurogenic lesions in all patients with spontaneous potentials, prolonged duration or augmentation of amplitude in motor unit potentials (MUPs), or a single pattern of MUP recruitment. About 17.8% (13/73) of the patients showed neurogenic lesions, mostly in the C7-8 level of the cervical cord, only in the upper extremity of affected side, whereas 35.6% (26/73) of the patients possessed lesions in the upper extremities bilaterally. A total of 46.6% (34/73) of patients exhibited abnormalities in the lower extremities, sterno- cleidomast or thoracic paravertebral muscle. Changes in motor NCS were significantly correlated with muscle strength.</p><p><b>CONCLUSIONS</b>EMG detects diffused subclinical neurogenic lesion in a high proportion of patients with Hirayama disease. Results of our study challenge the hypothesis that Hirayama disease is a type of cervical myelopathy.</p>

Value of anal sphincter electromyography, orthostatic hypotension and dizziness in diagnosing multiple system atrophy / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the value of anal sphincter electromyography (ASEMG), orthostatic hypotension (OH), and dizziness in diagnosing multiple system atrophy (MSA).</p><p><b>METHOD</b>The characteristics of ASEMG and OH were compared among patients with dizziness (MSA and non-MSA), patients without OH (MSA and non-MSA), and patients with probable MSA (OH and non-OH).</p><p><b>RESULTS</b>Totally 476 patients underwent ASEMG examinations. Dizziness was the onset symptom in 69 patients. Between the MSA group and non-MSA group, the mean duration of dizziness [(14.6 +/- 2.1) vs. (12.8 +/- 2.0) ms, P < 0.01] and satellite potential occurrence rate [(22.7 +/- 11.8)% vs. (12.2 +/- 8.9)% , P < 0.01] were significantly different, while the OH rate (84.6% vs. 55.2% ) and the difference of the blood pressure between standing and supine positions were not significantly different. In 162 patients with symptom of dizziness, the mean duration of dizziness [(15.3 +/- 2.7) vs. (12.8 +/- 1.9) ms, P < 0.001], satellite potential occurrence rate [(25.4 +/- 12.8)% vs. (13.5 +/- 10.4)%, P < 0.001] , and difference of the diastolic blood pressure [(18.5 +/- 17.0) vs. (11.7 +/- 12.7) mmHg, P < 0.05] were significantly different between the MSA group and non-MSA group, while the normal rate of blood pressure at standing position (60% vs. 41.9%) and the difference of systolic blood pressure were not significantly different. In 146 patients with abnormal blood pressure at standing and supine positions, the mean duration of dizziness [(15.0 +/- 2.4) vs. (12.8 +/- 1.7) ms, P < 0.001] and satellite potential occurrence rate [(22.0 +/- 12.2)% vs. (10.6 +/- 8.5)%, P < 0.001] were significantly different between the MSA group (n = 61) and non-MSA group (n = 85). In 125 patients with probable MSA, the mean duration of dizziness [(15.5 +/- 2.4) vs. (15.9 +/- 2.2) ms, P > 0.05] and satellite potential occurrence rate [(24.3 +/- 12.6)% vs. (22.7 +/- 12.4)%, P > 0.05] were not significantly different between those with OH and those without OH. The rates of dizziness and the percentage of dizziness as the onset symptom were 93.2% and 52.3% in OH group and 44.4% and 8.3% in non-OH group.</p><p><b>CONCLUSIONS</b>ASEMG is better than OH in diagnosing patients with dizziness suspected as MSA. Neurogenic lesion can be found by ASEMG in patients without OH, which is helpful in the early diagnosis of MSA.</p>

Tumor necrosis factor-alpha polymorphism and secretion in myasthenia gravis / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To analyze the relationship between tumor necrosis factor-alpha (TNFalpha) gene promoter -308 polymorphism and myasthenia gravis (MG) in Chinese and analyze secretion of TNFalpha in peripheral blood mononuclear cells (PBMC) in MG patients.</p><p><b>METHODS</b>A biallelic polymorphism at position -308 in the promoter of TNFalpha gene was screened by PCR amplification and NcoI recognition site. One hundred and twenty-three MG cases and 115 healthy controls were included in this study. MG patients were classified to different groups according to clinical type, age at onset, and sex respectively. PBMC were isolated from 20 patients and 20 healthy controls, and then cultured in the presence or absence of phytohemagglutinin (PHA) and acetycholine receptors (AchR). The supernatants were harvested after incubation and stored until TNFalpha was assayed by enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>The frequency of TNFalpha-308 allele 2 (A) was found significantly increase in MG patients and showed a trend especially in late onset (> or =40 years) and male patients (P < 0.05). The allele A had no relationship with thymic pathogenesis in MG patients. But frequency of allele A was significantly higher in general type than in ocular type (P < 0.05). MG patients had a higher inducible level of TNFalpha by PHA and AchR, and could be down regulated after treatment.</p><p><b>CONCLUSION</b>Polymorphism in TNFalpha gene promoter -308 is associated with onset of MG. The microsatellite allele TNFalpha2 confer risk for the development of MG in Chinese patients. MG patients have a higher inducible level of TNFalpha.</p>

Effects of transcranial magnetic stimulation on motor cortical excitability and neurofunction after cerebral ischemia-reperfusion injury in rats / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To clarify the effects of repetitive transcranial magnetic stimulation (rTMS) on rat motor cortical excitability and neurofunction after cerebral ischemia-reperfusion injury.</p><p><b>METHODS</b>After determined awake resting motor threshold (MT) and motor evoked potentials (MEPs) of right hindlimbs, 20 Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) reperfusion injury, then rTMS were applied to rTMS group (n=10) at different time, while control group (n=10) received no stimulation. A week later, MT and MEPs were evaluated again, as well as neurological deficits and infarct volume. The effects of rTMS and MCAO reperfusion injury on these parameters were analyzed.</p><p><b>RESULTS</b>After MCAO reperfusion, both MT level and neurological deficit scores increased, distinct focal infarction formed, and latency of MEP elongated. Compared with the control group, the increased extent of MT and neurological scores of rats receiving rTMS were significantly lower (P < 0.05), as well as the infarct volumes reduced significantly (P < 0.05). But MEP was not affected by rTMS obviously. There was a positive linear correlation between postinjury MT and infarct volume (r = 0.64, P < 0.05).</p><p><b>CONCLUSION</b>rTMS may facilitate neurofunction recovery after cerebral ischemia-reperfusion. Postinjury MT could provide prognostic information after MCAO reperfusion injury.</p>

Clinical and electrophysiologicalfeatures of myasthenia gravis with myogenic damage in 53 patients / 中华神经科杂志

Objective To study the clinical and electrophysiological features of myasthenia gravis (MG)accompanied by myogenic lesion.Methods The data of the patients who were diagnosed MG accompanied by myogenic lesion from 1998 to 2006 were collected in EMG Room, Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and were retrospectively analyzed.Results In this group of 53 patients, myogenic lesion was found more often in patients with early-onset MG than those with late-onset(69.81% vs 30.20%), and among the early-onset patients the frequency of female was significantly higher than male(26 vs 11,X~2=5.281, P

Single fiber electromyography in the diagnosis of ocular myasthenia gravis: report of 90 cases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The aim of this study was to evaluate single fiber electromyography (SFEMG) in the diagnosis of ocular myasthenia gravis (OMG), compared with repetitive nerve stimulation (RNS) and blood concentration of antibody to acetylcholine receptor (AchRAb).</p><p><b>METHODS</b>SFEMG, RNS and AchRAb titration were measured in 90 patients with OMG (44 men, 46 women).</p><p><b>RESULTS</b>Markedly increased jitter and ratio of block in the frontalis and the extensor digitorum communis (EDC) were observed (83.3% and 61.1%, respectively). The mean jitter was 43.6 +/- 14.5 micros, and the percentages of jitter>55 micros and blocking were 16.9% +/- 19% and 3.5% +/- 9.5% respectively in the EDC. The mean jitter was 64.3 +/- 25.6 micros, and the percentages of jitter > 55 micros and blocking were 33.5% +/- 27.6% and 29.3% +/- 23.2% respectively in the frontalis. The percentage of abnormal RNS was 27.8% (25/90). There was an increased AchRAb titration in 29 (32.2%) of the 90 patients. Increased jitter, blocking was negatively correlated with maximum decrement to RNS (P < 0.01). 11.4% (4/35) of patients with abnormal RNS and 24.1% (7/29) patients with abnormal AchRAb were seen in the patients with normal SFEMG in the EDC.</p><p><b>CONCLUSION</b>SFEMG test showed the highest sensitivity in the diagnosis of OMG. To our knowledge, the three methods (SFEMG, RNS and AchRAb) are complementary in the diagnosis and differential diagnosis of OMG.</p>

Clinical significance of myasthenia gravis-related autoantibodies / 中华神经科杂志

Objective To investigate the clinical significance of myasthenia gravis (MG) associated autoantibodies.Methods Titin,ryanodine receptor (RyR)and acetylcholine receptor (AChR) antibodies were examined in the sera of 74 myasthenia gravies patients by ELISA.Results AChR,Titin, RyR antibodies were detected in 77.0% (57/74),39.2% (29/74) and 32.4% (24/74) of the MG patients,respectively.For thymoma MG,AChR,Titin and RyR antibodies were detected in 76.2% (16/21),71.4% (15/21) and 52.4% (11/21) respectively.For late onset MG,Titin and RyR antibodies were detected in 77.3% (17/22) and 50.0% (11/22) respectively.With respect to the modified Osserman classification,the positve rate for Titin and RyR antibodies is much higher in more severe patients (X~2= 16.094,P=0.001;X~2=11.226,P=0.011).Titin antibodies was significantly related with RyR antibodies (r=0.380,P=0.001).Conclusions Titin and RyR antibodies show high sensitivity for thymoma MG,and the combination of serological and radiological testing can increase both sensitivity and specificity in diagnosis of thymoma MG.The levels of the two antibodies may serve as important prognosis markers in MG.The induction of the immune response against Titin and RyR and the possible pathogenic effects of the two antibodies will be further studied.