Paraspinal and limb motor neuron involvement within homologous spinal segments in ALS.

OBJECTIVE: We studied the involvement of motor neuron groups innervating paraspinal muscles in amyotrophic lateral sclerosis (ALS) and evaluated the value of paraspinal muscle EMG in the diagnosis of the disease. METHODS: We used quantitative concentric needle EMG to study denervation and reinnervation in a paraspinal muscle and a limb muscle innervated by the C6 and L5 segments in 32 patients with ALS. As control subjects we studied 11 patients with peripheral neuropathy, and 46 non-neurogenic control subjects. RESULTS: We found similar abnormalities in motor-unit potentials (MUPs) in paraspinal and limb muscles in these two segments in ALS. Fasciculation potentials (FPs) were more frequent in limb muscles than in paraspinal muscles and fibrillations and sharp waves (fibs-sw) were most frequent in tibialis anterior. In peripheral neuropathy paraspinal muscles were normal but tibialis anterior showed very abnormal motor unit potentials. CONCLUSIONS: These results are consistent with generalised involvement of motor neurons in motor neuron pools in spinal segments in early stages of ALS progression. However, distally predominant fibrillations indicate susceptibility to ongoing denervation in reinnervated distal axons. Complex FPs of similar morphology to MUP analysis in the same early affected muscle suggests a proximal origin for these FPs at this phase. SIGNIFICANCE: Our observations emphasize the value of paraspinal muscle EMG in the electrophysiological diagnosis of ALS.     

Assessment of thoracic paraspinal muscles in the diagnosis of ALS

The distribution of muscle involvement, assessed clinically and electromyographically, was analyzed prospectively in 55 consecutive amyotrophic lateral sclerosis (ALS) patients and in 54 patients with other predominantly motor syndromes, some of whom were referred with suspected ALS. In ALS patients, distal limb muscles and thoracic paraspinal muscles were affected most frequently, more so than proximal limb and cranial muscles. The incidence of bulbar symptoms in ALS was greater in women than in men. These patterns suggest selective vulnerability of specific neuronal populations. The vulnerability of truncal muscles, illustrated by thoracic paraspinal wasting or head and shoulder drooping, was a helpful differential sign in diagnosing ALS. Thoracic paraspinal electromyography was especially valuable in distinguishing ALS from other disorders, such as combined cervical and lumbar spondylotic amyotrophy or polymyositis, which may masquerade as ALS. The finding of denervation atrophy on biopsy of thoracic paraspinal muscles was diagnostic in difficult cases. Because the thoracic paraspinal muscles are frequently affected in ALS and spared in spondylotic amyotrophy, their assessment provides a practical strategy in differentiating ALS from other motor syndromes.     

Electromyography of sternocleidomastoid muscle in ALS: a prospective study

Needle electromyography (EMG) of the tongue is difficult to perform because of frequent uncontrollable movement. We chose the sternocleidomastoid (SCM) muscle as a possible alternative for assessing the involvement of the rostral neuraxis in amyotrophic lateral sclerosis (ALS). We prospectively studied 21 ALS patients during our initial diagnostic evaluation. EMG parameters that we recorded included the presence of abnormal spontaneous activity, pattern of motor unit potential recruitment, and configuration of motor unit action potentials. For the six patients with bulbar-onset ALS, three had abnormalities in the SCM and three had abnormalities in the tongue. In contrast, for the 15 patients with limb-onset ALS, 9 had abnormalities in the SCM, and only 3 had abnormalities in the tongue. Our results demonstrate the utility of needle EMG of the SCM in the evaluation of ALS. EMG of the SCM carries a similar sensitivity as the tongue in ALS patients with bulbar symptoms, but is more sensitive than the tongue in patients without bulbar symptoms. SCM innervation includes the rostral cervical cord and brainstem, and EMG abnormalities in this muscle support a diffuse involvement, which is unique to ALS.     

Electrodiagnostic evaluation of motor neuron disorders

Amyotrophic lateral sclerosis (ALS) is the most common adult motor neuron disorder and leads usually to death within two to five years after diagnosis. Clinically, ALS presents with fasciculations, progressive weakness, muscle atrophy, and spasticity. It is a clinical diagnosis, supported by electrodiagnostic and laboratory tests. Nerve conduction studies (NCS) and needle electromyography (EMG) are essential in the evaluation of suspected ALS. NCS are primarily used to exclude any potentially treatable motor neuropathy that may mimic ALS. Standard nerve conduction studies should include at least four sensory and four motor nerves in an arm and leg. At least three sites in three different nerves should be stimulated when searching for conduction blocks, which may distinguish motor neuropathy from ALS. Needle EMG is very valuable as it can demonstrate widespread involvement of muscles that are not clinically weak. Characteristic findings include widespread non-myotomal denervation (both acute and chronic), with fibrillations and fasciculations. Extensive needle examination should include at least two limbs (arm and leg; at least five muscles each), thoracic paraspinal and bulbar muscles.     

Carcinoma of the tongue and bulbar-onset amyotrophic lateral sclerosis: unusual differential diagnosis

We present a 72-year-old woman with progressive dysphagia, dysarthria and tongue palsy who was initially diagnosed with bulbar-onset amyotrophic lateral sclerosis (ALS). However, the absence of atrophy or fasciculations in the tongue, as in other voluntary muscles, and the lack of reproducible neurophysiological evidence of denervation, prompted a revision of the diagnostic work-up, which eventually led to the discovery of a carcinoma of the tongue. This case report describes a relatively rare type of oropharyngeal carcinoma that, in its early stage, resembled a bulbar-onset ALS. This differential diagnosis is unusual, and it was fostered by the persistent lack of atrophy of the tongue and the absence of spreading of signs and symptoms of motor neuron degeneration.     

胸段脊旁肌肌电图在肌萎缩侧索硬化诊断中的作用

目的 研究胸段脊旁肌自发电位在诊断肌萎缩侧索硬化(amyotrophic lateral sclerosis，ALS)中的价值。方法 50例确诊的ALS患者分别行胸段脊旁肌自发电位、胸锁乳突肌运动单位，部分患者行舌肌自发电位检测；同时，将性别、年龄相匹配的30例根性损害的患者和30名健康人作为对照，行胸段脊旁肌自发电位检测。结果 50例ALS患者中，41例(82％)胸段脊旁肌肌电图可见大量纤颤电位和正锐波；胸锁乳突肌肌电图无一例见自发电位，但有48例(96%)运动单位时限增宽，波幅增高，符合慢性神经源性损害改变；6例患者行舌肌自发电位检测，3例可见自发电位。30例根性病变的患者中，2例(7％)可见胸段脊旁肌有少量自发电位；健康对照组未见胸段脊旁肌自发电位。结论 胸段脊旁肌大量自发电位对诊断ALS具有一定的敏感性。     

Muscle ultrasonography: a diagnostic tool for amyotrophic lateral sclerosis

ObjectiveIn a prospective study we tested whether muscle ultrasonography can differentiate between amyotrophic lateral sclerosis (ALS) and mimics. Furthermore, we assessed the ability of ultrasonography to identify subclinical lower motor neuron involvement.MethodsIn 59 patients, suspected for adult onset motor neuron disease, ultrasound scans were made of 12 different muscle groups. Echo intensity was determined and each muscle was screened for fasciculations. Ultrasonography was considered diagnostic for ALS when echo intensity was 1.5 SD above normal in at least two muscles and fasciculations were present in at least four muscles.ResultsUltrasonography differentiated between ALS and mimics with 96% sensitivity and 84% specificity. In the 27 ALS patients, ultrasonography detected 15 regions with lower motor neuron involvement that were negative using either clinical examination or needle EMG.ConclusionsMuscle ultrasound can differentiate between amyotrophic lateral sclerosis and mimics with high sensitivity and specificity, and is a sensitive tool to screen for regional lower motor neuron involvement.SignificanceMuscle ultrasonography is a promising tool in the diagnostic work up of ALS.     

Spontaneous electromyographic activity of the tongue in amyotrophic lateral sclerosis

Introduction: Detection of denervation in muscles in the craniobulbar area is important to assure widespread lower motor neuron involvement in the diagnosis of amyotrophic lateral sclerosis (ALS). The value of spontaneous activity analysis in needle electromyography (EMG) of the tongue has been questioned in the recent literature. Methods: Spontaneous activity in the tongue and sternocleidomastoid (SCM) muscles was reviewed retrospectively in 17 ALS patients. Results: Needle EMG showed spontaneous activity in the tongue in 14 of 17 patients (82%) and in 6 patients of 17 (35%) in SCM. Spontaneous EMG activity in the tongue was found in patients with and without bulbar symptoms. Conclusions: Needle EMG is a valuable method for assessing clinical and subclinical involvement of the tongue in patients with bulbar and limb onset ALS. Adequate relaxation of the tongue is a prerequisite for proper spontaneous activity recording. Muscle Nerve, 48: 296–298, 2013     

Motor responses evoked by transcranial magnetic stimulation and peripheral nerve stimulation in the ulnar innervation in amyotrophic lateral sclerosis: the effect of upper and lower motor neuron lesion

We studied the upper (UMN) and lower motor neuron (LMN) innervations of 159 hands from 81 patients with amyotrophic lateral sclerosis (ALS). Eleven patients with various chronic LMN disorders causing weakness in the abductor digiti minimi (ADM) muscle served as LMN controls. Thirty healthy subjects served as normal controls. Cortical motor threshold, central conduction time (CMCT), and motor-evoked response amplitude (MEP) after transcranial magnetic stimulation (TMS) were studied, and the MEP/M wave ratio was calculated. The data was analyzed in the ALS subjects in groups defined by ADM muscle strength and by the presence or absence of clinical signs of UMN involvement.

CMCT was not increased in the ALS or LMN disease groups. The threshold was higher in limbs with both weak ADM muscles and UMN signs. The MEP/M wave amplitude ratio was increased in weak muscles in the ALS patients, notably in limbs with no UMN signs, and also in weak muscles in patients with other chronic LMN disorders. It was frequently decreased in strong muscles. There was no difference between bulbar-onset and limb-onset ALS groups, and there was no correlation between threshold and disease duration. We suggest that expressing the data as an index and utilising the MEP/M wave amplitude ratio as a variable is a sensitive method for detecting UMN abnormality in ALS in particular in early affected muscles.     

Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings

OBJECTIVE: To describe the clinical, neurophysiological, and MRI findings in 10 patients with primary lateral sclerosis (PLS). RESULTS: The course of the disease was very slowly progressive. Spasticity due to upper motor neuron dysfunction was the most prominent sign, but EMG showed slight lower motor neuron signs, such as a mixed pattern on maximal voluntary contraction and enlarged motor unit potentials. One patient had clinically mild lower motor neuron involvement. Central motor conduction times (CMCT) were more prolonged in PLS than is the case in ALS. Minor sensory signs were found on neurophysiological examination, comparable with those in ALS. In four patients serum creatine kinase activity was raised. On MRI cortical atrophy was seen, most pronounced in the precentral gyrus and expanding into the parietal-occipital region. CONCLUSIONS: PLS is a distinct clinical syndrome, part of the range of motor neuron diseases. Besides pronounced upper motor neuron symptoms, mild lower motor neuron symptoms can also be found, as well as (subclinical) sensory symptoms. PLS can be distinguished from ALS by its slow clinical course, a severely prolonged MEP, and a more extensive focal cortical atrophy.     

Clinical utility of trapezius muscle studies in the evaluation of amyotrophic lateral sclerosis.

Needle electromyography (EMG) and determining the motor evoked potential (MEP) of the genioglossus (tongue) are difficult to perform in evaluation of the craniobulbar region in patients with amyotrophic lateral sclerosis (ALS). Needle EMG and MEP determination in the upper trapezius were carried out in 17 consecutive ALS patients. The needle EMG parameters recorded included abnormal spontaneous activity and motor unit action potential morphology. An upper motor neuron lesion was presumed when either response to cortical stimulation was absent, or the central conduction time was delayed (>mean + 2 SD). Of the 12 patients with limb-onset ALS, using needle EMG, 11 were found to have abnormalities in the upper trapezius, and only five in the tongue. Three of the six patients with isolated limb involvement had abnormal MEP findings. In conclusion, electrophysiological studies of the upper trapezius are useful in ALS patients without bulbar symptoms.     

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative disease of the motor system characterized by signs and symptoms of upper and lower motor dysfunction. This results in the presence of focal amyotrophies and pareses affecting voluntary muscles. Patients die after a few years, in most cases by respiratory failure. ALS is the most frequent motor neuron disease; however, its etiology and pathogenesis are only known in fragments. Its genetic basis is only partially understood and major gaps remain in the understanding of its pathogenesis with the basic principle of selective vulnerability and potentially resulting therapeutic consequences.     

Prognostic value of EMG genioglossus involvement in amyotrophic lateral sclerosis

ObjectiveTo evaluate the prognostic value of needle electromyography (EMG) genioglossus involvement in patients with amyotrophic lateral sclerosis (ALS) at diagnosis.MethodsWe separately explored the prognostic value of clinical bulbar lower motor neuron (LMN) signs and EMG genioglossus involvement using Cox proportional hazard models adjusted for age, gender, diagnostic delay, presence of bulbar upper motor neuron (UMN) signs, EMG cervical and lumbosacral region involvement, ALSFRS-R score and C9Orf72 gene status. Then, we compared the prognostic value of EMG masseter and genioglossus abnormalities in a subset of patients in whom both muscles were analysed.Results103 ALS patients were included in the study. Neurophysiological genioglossus involvement was associated with a shorter survival (p = 0.002), a shorter time to moderate dysphagia (p = 0.0001) and to severe dysarthria (p = 0.012). Its prognostic value was still evident in patients without clinical bulbar LMN signs. Bulbar clinical LMN signs were only associated with an earlier onset of moderate dysphagia (p = 0.0001). EMG masseter abnormalities did not reach statistical significance with regard to all the clinical milestones.ConclusionsGenioglossus EMG at diagnosis could provide important information about ALS progression rate. The masseter muscle seems to be less involved in ALS.SignificanceEMG genioglossus involvement is a prognostic factor in ALS.     

Motor unit changes in thoracic paraspinal muscles in amyotrophic lateral sclerosis

In 38 amyotrophic lateral sclerosis (ALS) patients and 28 controls, we performed motor unit potential (MUP) analysis in the C‐6 and T‐5 paraspinal and biceps muscles. In ALS cases, we found similar abnormalities in MUPs in paraspinal and limb muscles. Fasciculation potentials (FPs) were more frequent in biceps than in paraspinal muscles, but fibrillation potentials and positive sharp waves (fibs‐sw) were equally frequent in all three muscles. These results confirm the value of paraspinal MUP analysis in the diagnosis of ALS. © 2009 Wiley Periodicals, Inc. Muscle Nerve 39: 83–86, 2009     

Volumetric analysis reveals corticospinal tract degeneration and extramotor involvement in ALS.

BACKGROUND: Pathologic changes in the motor cortex and corticospinal tracts in ALS may be reflected by abnormal signal intensities on conventional MRI. The sensitivity of these changes in detecting underlying pathology remains unclear. METHOD: The authors used automated image analysis to quantify volumes of cerebral gray and white matter in 16 patients with ALS (eight limb onset, eight bulbar onset) and eight normal controls. Previously they had demonstrated a reduction in N-acetyl aspartate/creatine + phosphocreatine (NAA/[Cr + PCr]) measured by (1)H-MRS in the subcortical white matter in the motor cortex region in the patients with bulbar-onset ALS. To determine whether this resulted from axonal degeneration, they also compared gray and white matter volumes in the patients with limb- and bulbar-onset ALS. RESULTS: There were no differences in the total brain volumes of gray or white matter for the three subject groups (p > 0.23). Comparison of the total ALS group and controls revealed localized deficits in gray matter volume centered on Brodmann areas 8, 9, and 10 bilaterally. Comparison of the patients with limb- and bulbar-onset ALS revealed deficits in the white matter volume in the bulbar-onset group, extending bilaterally from the precentral gyrus into the internal capsule and brainstem, consistent with the course of the corticospinal tract. There was no loss in gray matter volume in the precentral gyri. CONCLUSIONS: The loss of gray matter in the frontal regions (total ALS group) provides further support that ALS is a multisystem disorder. In addition, there is in vivo evidence of axonal degeneration in the subcortical white matter in the motor region in patients with bulbar-onset ALS. This is consistent with a "dying back" process affecting cortical motoneurons in bulbar-onset ALS.     

不同起病部位的ALS病人异常肌电区域分布研究

目的 :探讨不同起病部位的ALS病人在 4个下运动神经元支配区域异常肌电的分布情况。方法 :对 10 2例临床诊断为ALS的病人分别行 4组下运动神经元区域 (脑干 ,颈 ,胸 ,腰骶髓 )的针极肌电图检查。对 87例同时进行了胸锁乳突肌的检查。结果 :4组肌电检查区域的结果示 :颈段与胸段异常率在各起病组中最高 ,脑干及腰骶段在各组中异常率不同 (差异有显著意义 ,P <0 0 5 ) ;胸锁乳突肌上、下肢起病组的异常率均高于同组的脑干支配肌。结论 :在ALS病人中 ,异常肌电的分布与起病部位有关。不论哪一部位起病 ,4个区域均可受累 ,因此必须全都检查。胸锁乳突肌具有特殊的诊断及鉴别诊断价值     

斜方肌肌电图在肌萎缩侧索硬化早期诊断中的应用

目的 探讨斜方肌肌电图在检测肌萎缩侧索硬化(ALS)延髓部下运动神经元损害中的价值.方法 对100例ALS患者、80例颈椎病患者和100名健康志愿者进行斜方肌肌电图检测,AKS组和颈椎病组同时进行胸锁乳突肌、第一骨间肌、腹直肌、胫前肌肌电图检测,比较3组肌电图的差异.颈椎病组中43例患者进行手术前后斜方肌肌电图比较.结果 ALS组中,病程≤8个月的患者斜方肌肌电图自发电位的出现率高于病程>8个月者[分别为21/30(70%)和28/70(40%),X~2=7.56,P=0.004];斜方肌肌电图与胸锁乳突肌肌电图异常率比较差异无统计学意义.ALS组[波幅(1086.9±152.6)μV,时限(17.2±6.5)ms,多相波23.6%±3.4%]与对照组[波幅(606.7±82.7)μV,时限(11.6±1.8)ms,多相波12.8%±2.2%;q=9.27、4.57、4.12,均P<0.01]、ALS组与颈椎病组[术前,波幅(615.7±90.3)μV,时限(12.1±2.0)ms,多相波13.5%±2.4%]间运动单位动作电位(MUAP)各参数比较,差异有统计学意义(q=8.32、4.25、4.23,均P<0.01).颈椎病患者手术前后斜方肌肌电图MUAP各参数无明显变化,5例术后发现少量自发电位.结论 斜方肌肌电图可作为检测ALS延髓部下运动神经元损害的辅助手段,特别是早期可见自发电位增多. 1.6±1.8)ms,多相波12.8%±2.2%;q=9.27、4.57、4.12,均P<0.01]、ALS组与颈椎病组[术前,波幅(615.7±90.3)μV,时限(12.1±2.0)ms,多相波13.5%±2.4%]间运动单位动作电位(MUAP)各参数比较,差异有统计学意义(q=8.32、4.25、4.23,均P< .01).颈椎病患者手术前后斜方肌肌电图MUAP各参数无明显变化,5例术后发现少量自发电位.结论 斜方肌肌电图可作为检测ALS延髓部下运动神经元损害的辅助手段,特别是早期可见自发电位增多. 1.6±1.8)ms,多相波12.8%±2.2%;q=9.27、4.57、4.12,均P<0.01]、ALS组与颈椎病组[术前,波幅(615.7±90.3)μV,时限(12.1±     

Use of needle electromyography for diagnosis of radiculopathies

Radiculopathy is sometimes evaluated with needle electromyography as additional examination to radiographic imaging. The purpose of this study was to determine the optimal needle electromyography protocol and the use of needle electromyography in the diagnosis of radiculopathy. The authors analysed English language writings from years 1981-2000. The selected studies reported a wide range of needle EMG abnormalities--from about 30 to 100% of pathological EMGs. That is caused by wide variety of patient populations and various EMG protocols. EMG of leg muscles in radiculopathy can consist of the assessment of the spontaneous activity only or be completed with the assessment of motor unit potential (MUP). The EMG of paraspinal muscles assesses spontaneous activity only. The number of abnormalities in needle EMG grows with the presence of characteristic radiculopathy symptoms, but positive EMG examinations are of importance only in cases where diagnosis is complicated. The rate of pathological results is higher when needle electromyography is used in the muscles of paraspinal region and extremities at the same time. The assessment of the spontaneous activity in extremity muscles alone minimizes the influence of error- causing factors on the EMG result. Nevertheless lack of assessment of motor units potentials makes electromyographic investigation of chronic radiculopathy impossible. Sensitivity and specificity of the method have to be determined before the clinical use of the assessment of MUP in chronic radiculopathy, especially in patients without motor weakness. Needle EMG abnormalities correlate with radiological findings in limited range as would be expected from the occurrence of radiological findings in asymptomatic patients and overlapping innervations of myotomes.     

Mirror movements and ipsilateral motor evoked potentials in ALS.

It can be difficult to detect upper motor neuron (UMN) involvement in early amyotrophic lateral sclerosis (ALS). The present study tested the usefulness of mirror movements (MMs), i.e., contralateral coactivation of hand muscles, as a UMN sign in ALS. Thirty-seven patients with possible, probable or definite ALS and 19 patients with suspected ALS without clinical signs of UMN involvement, 21 disease controls and 15 healthy volunteers were included. MMs were studied clinically, electromyographically and by transcranial magnetic stimulation (TMS), looking for ipsilateral motor evoked potentials (IMEPs). MMs were observed clinically in 15 ALS patients (27%) and electromyographically in 28 (50%). IMEPs in the abductor pollicis brevis muscle following TMS were recorded in 34 (61%) of all ALS patients and in nine (47%) out of 19 patients with suspected ALS, but not in healthy controls. Central motor conduction times were prolonged in 15 ALS patients (27%). It is concluded that MMs, especially if studied by EMG and TMS (IMEPs) can essentially improve detection of UMN involvement, especially in early stages of ALS.     

Distal Predominance of Electrodiagnostic Abnormalities in Early‐Stage Amyotrophic Lateral Sclerosis

Introduction: In this study we compared the electrodiagnostic (EDX) yield of limb muscles in revealing lower motor neuron (LMN) dysfunction by electromyography (EMG) in early‐stage amyotrophic lateral sclerosis (ALS). Methods: This investigation was undertaken as a retrospective review at a single center. Results: Our study included 122 consecutive patients with possible ALS, as defined by revised El Escorial criteria. Distal limb muscles showed more frequent EMG abnormalities than proximal muscles. EDX yield was found to be higher in the limb where weakness began and when clinical signs of LMN dysfunction were evident. Adoption of the Awaji criteria significantly increased the yield of EMG‐positive segments in the cervical (P < 0.0005) and lumbosacral (P < 0.0001) regions, and upgraded 19 patients into the probable category and 1 patient into the definite category. Discussion: EMG abnormalities are predominant in the distal limb in early‐stage ALS. A redefinition of an EDX‐positive cervical or lumbosacral segment, with an emphasis on distal limb muscles, may result in an earlier ALS diagnosis. Muscle Nerve 58 : 389–395, 2018