Electromyography And Nerve Conduction Studies Research Articles

Nerve Transfer Surgery in Acute Flaccid Myelitis: Prognostic Factors, Long-Term Outcomes, Comparison With Natural History

BackgroundNerve transfer surgery is sometimes offered to patients with acute flaccid myelitis (AFM). The objectives of this study were to evaluate surgical efficacy, assess which clinical and neurophysiological data are valuable for preoperative planning, and report long-term outcomes. MethodsThis is a single-center, retrospective case series of patients with AFM who received nerve transfer surgery. All patients had preoperative electromyography and nerve conduction studies (EMG/NCS). Matched control muscles that did not receive nerve transfer surgery were defined in the same cohort. ResultsTen patients meeting inclusion criteria received a total of 23 nerve transfers (19 upper extremity, four lower extremity). The mean age at symptom onset was 3.8 years, surgery was 0.5 to 1.25 years after diagnosis, and mean follow-up was 2.3 years (range 1.3 to 4.5 years). Among muscles with preoperative strength Medical Research Council (MRC) grade 0, muscles receiving nerve transfers performed significantly better than those that did not (MRC grade 2.17 ± 0.42 vs 0 ± 0, respectively, P = 0.0001). Preoperative EMG/NCS predicted worse outcomes in recipient muscles with more abundant acute denervation potentials (P = 0.0098). Donor nerves found to be partially denervated performed equally well as unaffected nerves. Limited data suggested functional improvement accompanying strength recovery. ConclusionsNerve transfer surgery is an effective strategy to restore strength for patients with AFM with persistent, severe motor deficits. Postoperative outcomes in patients with complete paralysis are better than the natural history of disease. This study demonstrates the utility of preoperative clinical and electrophysiological data in guiding patient selection for nerve transfer surgery.

Lower limb axonal mononeuropathies as sequelae of COVID-19: a case report and review of literature

BackgroundNeurological symptoms and complications of Coronavirus disease 2019 (COVID-19) were seldom discussed in the literature initially. Neurological symptoms such as headache, dizziness, anosmia, hypogeusia, and neuralgia are, however, now being reported commonly. Mononeuropathies are rare complications of COVID-19, with most cases associated with prolonged intensive care stay.Case presentationA 61-year-old gentleman with prior history of well-controlled diabetes and hypertension was recently treated for COVID-19 pneumonia with supplemental oxygen and positive pressure ventilation. He now presented with left-sided foot weakness two weeks after recovering from the viral illness. On examination he had normal bulk and tone and a power of 4/5 in proximal and distal muscles of bilateral lower limbs except for ankle dorsiflexion on the left which was 2/5. He also had absent ankle and knee reflexes bilaterally with bilateral flexor plantar reflexes. Since the patient had no back pain and the sensory system was normal, the lesion was localized to the peripheral nerves and a Nerve Conduction Studies and Electromyography (NCS/EMG) was done. NCS/EMG showed findings suggestive of axonal mononeuropathies. Relevant workup done to identify the cause of mononeuropathy was negative including infectious and autoimmune workup. Since diabetes was well-controlled and he had no intensive care stay his findings were presumed to be associated with resolving COVID-19 infection. The patient underwent aggressive daily physical therapy and has started to show improvement in symptoms.ConclusionsComplications such as mononeuropathies should be kept in mind in patients recovering from COVID-19 infection, since timely diagnosis can improve clinical outcomes in patients.

P-PN022. Transthyretin familial amyloid polyneuropathy in multi-ethnic Malaysians

Introduction . Familial amyloid polyneuropathy (FAP) is a rare autosomal dominant peripheral neuropathy. We report a case series of Malaysian FAP patients. Methods . Patients with definite (genetically confirmed) FAP seen at the University of Malaya Medical Centre between 2008 till 2019 were included in the series. The patients’ demographic and clinical features and investigations including nerve conduction studies and electromyography (NCS/EMG), echocardiography, sural nerve biopsy and hATTR mutation are reported. Results . A total 21 index cases were seen. Nineteen (90%) were ethnic Chinese, one ethnic (5%) Malay and one (5%) ethnic Indian; Fourteen (67%) were men. Mean age of onset of symptoms was 56.1 ± 10.5 years (range: 31-73). Nineteen (90%) patients presented with numbness and weakness of the limbs while two had postural hypotension. Fifteen (71%) patients had positive family history. NCS/EMG showed sensorimotor polyneuropathy in 19 (90%) patients; fifteen (71%) showing axonal neuropathy. Amyloid deposits were seen on nerve biopsy in ten patients and rectal, leptomeningeal and endomyocardial biopsies in 1 patient respectively. The latter was diagnosed as familial amyloid cardiomyopathy (FAC). Sixteen patients (76%) had abnormal cardiac echocardiogram with amyloid deposits. Fifteen Chinese patients (71%) carried the Ala97Ser hATTR mutation while the FAC patient has Asp39Val mutation. Our Malay patient had Glu54Lys mutation and Indian patient had Gly67Val mutation. Two patients carried Val30Met mutation. Autonomic function test was abnormal in all 7 patients in whom they were carried out. Conclusion . FAP in Malaysians is seen mainly among ethnic Chinese, in whom Ala97Ser may be a common mutation. This is also the reported “hotspot” mutation for FAP reported in Taiwan but not in China. Similar to Taiwan, Chinese-Malaysians are descended from immigrants from Southern China. Similar to Taiwanese patients, our FAP patients with Ala97Ser mutation, present with late-onset progressive sensorimotor polyneuropathy and cardiac involvement was common.

A Clinician's Approach to Peripheral Neuropathy.

Peripheral neuropathies are a group of disorders that affect the peripheral nervous system, for which hundreds of etiologies have been identified. This article presents a stepwise approach to the evaluation and workup of peripheral neuropathy, which starts with a detailed history of symptoms, family and occupational history, and a neurological as well as general physical exam. Pattern recognition of various neuropathies can help to build a differential diagnosis based on the presentation. Such patterns include acute versus chronic, primary demyelinating versus axonal, hereditary versus acquired, asymmetric versus symmetric, presence of facial palsies, sensory or motor predominant, and presence of prominent autonomic symptoms. Early categorization of the type of neuropathy can help focus the workup for peripheral neuropathy. Nerve conduction studies and electromyography (NCS/EMG) is the primary diagnostic tool in the evaluation of patients with large-fiber polyneuropathy. One of the most important roles of NCS/EMG is to help categorize polyneuropathy as primary axonal versus primary demyelinating. The finding of a primary demyelinating polyneuropathy narrows the differential diagnosis of polyneuropathy dramatically and increases the chances of finding a treatable etiology. Laboratory workup includes serum studies and potentially cerebrospinal fluid, genetic studies, immunological markers, and fat pad biopsy for select patients. Skin biopsy may be used to assess intraepidermal nerve fiber density if small-fiber neuropathy is suspected, and nerve biopsy may be useful in select cases. In recent years, magnetic resonance imaging and neuromuscular ultrasound have also shown promise in the evaluation of peripheral neuropathy. Identification of the etiology of neuropathy is crucial and often time-sensitive, as an increasing number of causes are now reversible or treatable.

CLINICAL DECISION MAKING AND DIFFERENTIAL DIAGNOSIS IN A CYCLIST WITH UPPER QUARTER PAIN, NUMBNESS, AND WEAKNESS: A CASE REPORT

Differentiating between cervical nerve root and peripheral nerve injuries can be challenging. A phenomenon known as double crush syndrome may increase the susceptibility to injury and symptoms at other locations along the course of the nerve. The purpose of this case report is to describe the physical therapy differential diagnosis and management of a cyclist with upper extremity pain, weakness, and paresthesia. The subject was referred to physical therapy with a diagnosis of cervical disc disease. His chief complaints were chronic neck and right shoulder pain as well as a recent onset of right hand numbness and weakness following 100-mile bike ride one month prior. Diagnostic imaging revealed multi-level degenerative changes of the cervical spine. Initial electromyography and nerve conduction studies (EMG/NCS) indicated right ulnar neuropathy at the elbow. The ultimate incorporation of ulnar nerve mobilizations in various positions immediately decreased symptoms. In light of the subject's improvement after ulnar nerve mobilizations, imaging findings, and EMG/NCS findings, the subject's presentation was consistent with a double crush syndrome with C8 nerve root compression and distal ulnar nerve compression at the elbow. The subject demonstrated full resolution of all symptoms, 0% disability on the Neck Disability Index, 8.3% disability of the Disabilities of the Arm, Shoulder, and Hand questionnaire, normal EMG/NCV findings, and unrestricted return to work and endurance cycling at three months and maintained at one year. He did not require hand surgery. This case report highlights the importance of continual clinical re-examination and re-assessment with ancillary diagnostic testing, especially if chosen interventions are not eliciting desired responses. The identification of key risk factors, such as occupation and recreational activities is imperative in achieving the most efficacious clinical treatment. In this case, the recognition of a double crush syndrome assisted in optimizing the physical therapy plan of care and the subject ultimately achieving full recovery. Level 4.

A Descending Cranial Nerve Palsy During the Christmas Holidays

A previous healthy 11-year-old child with a 24-hour history of asthenia, diplopia, dysarthria, dysphonia, swallowing difficulty, and vomiting was admitted to our institution on Christmas eve. The child complained of perioral paresthesias and blurry vision 2 days prior to admission and an unusual tiredness after skiing on the day of admission. He presented with a temperature of 36.8°C, blood pressure 100/70 mm Hg, pulse 80 beats/min, respiratory rate 20/min, and oxygen saturation 99% on room air. He was awake, well oriented and his physical examination was within normal limits. Neurological examination showed bilateral ophthalmoplegia with unreactive pupils, dysphonia, dysphagia with minimal limb weakness with associated hyporeflexia. Sensation was maintained, but he presented with urinary retention described as a poor urinary stream with intermittent flow, straining, and a sense of incomplete voiding and hesitancy. A complete blood count, electrolytes, arterial blood gas, C-reactive protein and herpes virus 1 and 2 (HSV-1 and HSV-2), Epstein-Barr virus (EBV) antibodies were within the normal range. Cerebrospinal fluid (CSF) examination was unremarkable (glucose 81 mg/dL, normal values 40-70), protein 20 mg/dL (normal values 15-45), lactate 11.7 mg/dL (normal values 10.8-19.8), and no erythrocytes or leucocytes. Polymerase chain reaction (PCR) for neurotropic viruses (human herpes virus 6, human herpes virus 7, human herpes virus 8, adenovirus, Parvovirus, EBarrV, herpes simplex virus 1 and 2, and varicella-zoster virus), cultures for meningococcus and fungi, and serology for Borrelia, Chlamydia Pneumoniae, enterovirus, influenza A and B, metapneumovirus, morbillivirus, and Mycoplasma Pneumoniae were all negative. The electroencephalography (EEG) was also normal. Intoxication or snakebite were excluded by medical history, a detailed neurological examination, and laboratory tests (urine and plasma toxicology screen for amphetamines, cannabinoids, cocaine, opiates, phencyclidine,alcohol, benzodiazepines and tricyclic antidepressants). There was no history of ingestion of homemade or rotten food that could contain botulinum spore or toxins. Twenty-four hours after admission, the patient developed respiratory failure and areflexia of the upper limbs requiring mechanical ventilation and admission to the pediatric intensive care unit (PICU). Repeat CSF examination showed normal glucose, protein and lactic acid, negative bacterial cultures, and PCR for viruses. No albuminocytologic dissociation was observed. Under the working diagnosis of a Miller-Fisher syndrome (MFS), the child was treated with intravenous immunoglobulin G (IgG) infusion (400 mg/kg) for 5 days with no clinical response, followed by 5 cycles of plasmapheresis. The child gradually recovered and it was possible to perform electromyography and nerve conduction studies (EMG/NCSs) which showed a normal conduction pattern. The edrophonium test, antibodies to voltage-gated calcium channels, to acetylcholine receptors (AChRs), and anti-ganglioside autoantibodies (IgG and IgM for GM1, GM2, GD1a, GD1b, and GQ1B) were also negative. A diagnostic result was received.

Heterogeneous patterns of tissue injury in NARP syndrome

Point mutations at m.8993T>C and m.8993T>G of the mtDNA ATPase 6 gene cause the neurogenic weakness, ataxia and retinitis pigmentosa (NARP) syndrome, a mitochondrial disorder characterized by retinal, central and peripheral neurodegeneration. We performed detailed neurological, neuropsychological and ophthalmological phenotyping of a mother and four daughters with NARP syndrome from the mtDNA m.8993T>C ATPase 6 mutation, including 3-T brain MRI, spectral domain optical coherence tomography (SD-OCT), adaptive optics scanning laser ophthalmoscopy (AOSLO), electromyography and nerve conduction studies (EMG-NCS) and formal neuropsychological testing. The degree of mutant heteroplasmy for the m.8993T>C mutation was evaluated by real-time allele refractory mutation system quantitative PCR of mtDNA from hair bulbs (ectoderm) and blood leukocytes (mesoderm). There were marked phenotypic differences between family members, even between individuals with the greatest degrees of ectodermal and mesodermal heteroplasmy. 3-T MRI revealed cerebellar atrophy and cystic and cavitary T2 hyperintensities in the basal ganglia. SD-OCT demonstrated similarly heterogeneous areas of neuronal and axonal loss in inner and outer retinal layers. AOSLO showed increased cone spacing due to photoreceptor loss. EMG-NCS revealed varying degrees of length-dependent sensorimotor axonal polyneuropathy. On formal neuropsychological testing, there were varying deficits in processing speed, visual–spatial functioning and verbal fluency and high rates of severe depression. Many of these cognitive deficits likely localize to cerebellar and/or basal ganglia dysfunction. High-resolution retinal and brain imaging in NARP syndrome revealed analogous patterns of tissue injury characterized by heterogeneous areas of neuronal loss.Electronic supplementary materialThe online version of this article (doi:10.1007/s00415-010-5775-1) contains supplementary material, which is available to authorized users.

Clinical Reasoning: A 34-year-old woman with recurrent bouts of acral paresthesias

A 34-year-old, previously healthy woman presented with a 3-year history of persistent numbness and tingling in her feet ascending to the knees. She was a lifelong long-distance runner, and she normally experiences numbness and tingling in both feet while running that resolve within minutes of stopping her exercise. Three years ago, she developed diarrhea that was followed a week later by paresthesias in her feet and legs with a stocking distribution to the knees. Her symptoms were associated with a transient feeling of overwhelming fatigue, limiting her ambulation to 1 city block. She did not, however, have any functional weakness. After 2 weeks, milder hand and left face paresthesias developed. Four weeks later, her symptoms plateaued and persisted. Three months later, she developed more intense paresthesias and a sensation of “crawling” below both knees. At that time, she was seen at another hospital, where the examination showed bilateral pes cavus and hammertoes. There was no nerve thickening. Cranial nerves were intact. Strength was normal except for mild bilateral thenar weakness and slight difficulty with heel walking. The deep tendon reflexes were decreased at the arms and ankles. There was decreased pinprick sensation in the feet in a stocking-glove distribution with hyperalgesia. Vibration was moderately diminished at the ankles. Nerve conduction studies and electromyography (NCS/EMG) at that time showed uniform, mild conduction velocity slowing of both sensory and motor conduction with borderline prolonged distal latencies in the median and ulnar nerves. She was treated with a 1-month taper of prednisone beginning with 80 mg daily. The crawling sensation resolved and the paresthesias became less intense and stabilized. She was able to resume distance running, but still had persistent, mild numbness in her feet with bouts of increasing intensity every several months. Three years later, the patient presented to us for a …

Small fiber neuropathy associated with multiple myeloma and IgA monoclonal gammopathy

Dear Editor,Monoclonal gammopathy (MG) is frequent in patients withperipheral neuropathy of otherwise undetermined etiology[1]. Clinically, MG-associated neuropathy usually manifestsas a slowly progressive sensorimotor polyneuropathy withnumbness and ataxia, with rare involvement of small nervefibers [1–4].Case reportA 33-year-old Caucasian woman with stage IA multiplemyeloma [5] presented with a 4-year history of painfulneuropathy. She was diagnosed with myeloma 18 months agoand treated with thalidomide and later fludarabine at anoutside hospital. Neuropathic pain continued to worsen afterchemotherapy and was described as a severe deep achegraded 10/10 that worsened with activity, restricting her to theuse of a motorized wheelchair. Laboratory testing showedmonoclonal IgA λ protein at 1.91 g/dl, with elevated freelight chains in the serum at 84.9 mg/l (normal 5.7 –26.3 mg/l).There were no skin or endocrine abnormalities. Bone marrowbiopsy and fat pad biopsy were negative for amyloid, butshowed 20% myeloma cell infiltration rate in the marrow.There was no history of diabetes. Current medicationsincluded transdermal fentanyl patch, pregabalin, sertraline,and hydrocodone. Examination showed normal sensation tovibration and proprioception, with mildly decreased sensationto pinprick and cold temperature below ankles. Cranialnerves, muscle strength, deep tendon reflexes, proprioception,and coordination were normal. Nerve conduction studies andelectromyography were normal. Semithin plastic and paraffinsections of sural nerve biopsy were suggestive of small nervefiber dropout, without evidence of inflammation or amyloid-osis. Quantitative sensory testing (QST) using CASE IV (WRElectronics, Stillwater, MN, USA) showed decreasedsensory thresholds to vibration (>95th percentile in the leftfoot and >99th percentile in the left hand and right foot;normal 99th percentile inboth feet and the left hand). Neuropathic symptoms did notimprove after plasmapheresis. Subsequent MRI of the spineshowed diffusely abnormal bone marrow signal in cervical,thoracic, and lumbar regions, and serum electrophoresisshowed rise of β-2-microglobulin. Subsequently, patientunderwent chemotherapy with cyclophosphamide and mel-phalan, followed by autologous peripheral blood stem celltransplantation. At 1 year after transplantation, there wasno significant change in her neuropathic pain.DiscussionSmall fiber neuropathy has been defined as a peripheralneuropathy manifest by paresthesias with findings of small-fiber dysfunction on examination, specialized testing (e.g.,

Detection of small‐fiber neuropathy by sudomotor testing

The symptoms of burning sensation affecting the feet, thought to be due to a distal small-fiber neuropathy (DSFN) affecting somatic unmyelinated fibers, are usually accompanied by vasomotor or sudomotor changes suggestive of involvement of autonomic fibers. We therefore examined the relationship between pattern of anhidrosis and DSFN and its etiology, comparing patients with "pure" DSFN (with normal nerve conduction) to those with clinical DSFN (minor conduction abnormalities). We reviewed 125 cases with a clinical phenotype of DSFN. These patients had distal burning discomfort, variable sensory deficits, and intact motor function. All had undergone assessment with thermoregulatory sweat test (TST), autonomic reflex screen (ARS), and nerve conduction studies and electromyography (NCS/EMG). TST showed a distal pattern of anhidrosis in 74%. The quantitative sudomotor axon reflex test (QSART) was abnormal in 74%, with 80% of those having a length-dependent pattern of anhidrosis/hypohidrosis. In total, 93% of patients had a distal pattern of abnormality on QSART or TST. The Composite Autonomic Severity Score (CASS) was used to quantify the severity and distribution of autonomic deficits: 98% had CASS abnormality (sudomotor, 98%; adrenergic, 43%; cardiovagal, 35%). EMG was normal or showed unrelated abnormalities in 75%. The most common etiologies of DSFN were idiopathic (73%), presumed hereditary (18%), and diabetes (10%). Sudomotor examination is thus a highly sensitive detection tool in DSFN. Autonomic involvement is mainly distal, and additionally may involve adrenergic and the long cardiovagal fibers.

Seasonal distribution and demographical characteristics of carpal tunnel syndrome in 1039 patients.

To describe the demographic characteristics of gender, age, and presence of repetitive movements, intake of alcohol and non-steroid anti-inflammatories (NSAI), medical specialties that referred patients to nerve conduction studies and electromyography (NCS-EMG), school attainment, and seasonal distribution in patients with a neurophysiological diagnosis of carpal tunnel syndrome (CTS) in the State of Rio Grande do Sul, Brazil. A series of 1039 patients (1549 hands) with neurophysiologically defined CTS was studied. Patients were referred for NCS-EMG in 3 universities and 2 private services, from August 2001 to January 2003. All patients completed a questionnaire containing demographic information. The diagnosis of CTS was established following a pre-established protocol, with defined diagnostic criteria. Around one fourth of patients had already performed NCS-EMG; the greatest frequency of CTS was observed in women (5.6:1) and in patients above the age of 40. Most patients reported performing repetitive movements in their daily routine (69.7%); 12.9% reported use of NSAI and 14.9% regular intake of alcoholic beverages. A greater frequency of CTS was observed in the months of July and August, when compared to the other months of the year. Around 2/3 of the study population had completed at least secondary school. Most requests of nerve conduction studies did not provide a diagnostic hypothesis (59.9%) and neurophysiologic studies were requested mostly by traumatology/orthopedics (71.1%). We have concluded that, in our environment, CTS shows some demographical characteristics that are similar to what the literature describes. Also, we have found that most of our sample concluded at least secondary school, and was referred to neurophysiologic studies by orthopedists. To be pointed out is the seasonal distribution of CTS, which demonstrates a significant association with winter months.