Electrodiagnostic techniques in the evaluation of diseases affecting skeletal muscle

Electrodiagnostic Evaluation of Individuals Implanted With Extracellular Matrix for the Treatment of Volumetric Muscle Injury: Case Series

BACKGROUND

Electrodiagnosis can reveal the nerve and muscle changes following surgical placement of an extracellular matrix (ECM) bioscaffold for treatment of volumetric muscle loss (VML).

OBJECTIVE

The purpose of this study was to characterize nerve conduction study (NCS) and electromyography (EMG) changes following ECM bioscaffold placement in individuals with VML. The ability of presurgical NCS and EMG to be used as a tool to help identify candidates who are likely to display improvements postsurgically also was explored.

DESIGN

A longitudinal case series design was used.

METHODS

The study was conducted at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh. Eight individuals with a history of chronic VML participated. The intervention was surgical placement of an ECM bioscaffold at the site of VML. The strength of the affected region was measured using a handheld dynamometer, and electrophysiologic evaluation was conducted on the affected limb with standard method of NCS and EMG. All measurements were obtained the day before surgery and repeated 6 months after surgery.

RESULTS

Seven of the 8 participants had a preoperative electrodiagnosis of incomplete mononeuropathy within the site of VML. After ECM treatment, 5 of the 8 participants showed improvements in NCS amplitude or needle EMG parameters. The presence of electrical activity within the scaffold remodeling site was concomitant with clinical improvement in muscle strength.

LIMITATIONS

This study had a small sample size, and participants served as their own controls. The electromyographers and physical therapists performing the evaluation were not blinded.

CONCLUSIONS

Electrodiagnostic data provide objective evidence of physiological improvements in muscle function following ECM placement at sites of VML. Future studies are warranted to further investigate the potential of needle EMG as a predictor of successful outcomes following ECM treatment for VML.

The neurologic examination and neurodiagnostic techniques for reptiles

This article will focus on specifics of performing the neurologic examination and neurodiagnostic testing in reptiles, and how these examinations differ from those performed in more conventional species. Physical examination and history are discussed, as well as invasive and noninvasive testing modalities.

Padronização da determinação da velocidade de condução nervosa sensitiva dos nervos tibial e peroneal de cães clinicamente sadios, pela utilização de eletrodos de superfície

O presente trabalho teve como objetivo a padronização dos valores de referência de velocidade de condução nervosa sensitiva dos nervos tibial e peroneal em cães clinicamente sadios, pela utilização de eletrodos de superfície. Em todos os sítios de estimulação, captação, referência e terra foram utilizados eletrodos do "tipo jacaré", exceto na captação do estímulo no nervo peroneal, próximo à articulação fêmur-tibial, onde o registro só foi possível com a utilização de eletrodo de agulha. Foram utilizados 30 cães, 11 machos e 19 fêmeas, sem raça definida, com idade entre dois e seis anos. Os valores médios das medidas dos potenciais evocados pela estimulação sensitiva dos nervos tibial e peroneal foram: latência inicial, 1,82±0,30ms (1,30 a 2,55ms) e 1,57±0,29ms (1,01 a 2,16ms), amplitude de pico a pico, 96,48±45,78miV (41,6 a 214miV) e 121,25±57,49miV (54,8 a 299miV) e duração, 1,97±0,69ms (1,01 a 3,56ms) e 2,37±0,85ms (1,11 a 3,94ms), respectivamente. Os valores médios das medidas de velocidade de condução nervosa sensitiva dos nervos tibial e peroneal foram, respectivamente, 62,14+7,71ms (50,0 a 77,2ms) e 65,18+6,42ms (53,8 a 79,2ms), respectivamente.

Neurologic conditions causing lameness in companion animals

Animals presented with non-weight-bearing lameness are a diagnostic challenge for the veterinarian. It is extremely important to distinguish between orthopedic and neurologic causes of lameness, because the diagnostic and therapeutic plans can be quite different. Myopathies can be confused with orthopedic disease because of gait abnormalities and associated muscle pain. Common myopathies seen in companion animal medicine include polymyositis, muscular dystrophy, endocrine and infectious myopathies, and myasthenia gravis. Lameness caused by disease of the nerve root or nerve is confused with orthopedic disease because of the disturbances of a nerve's sensory distribution (nerve-root signature) or disruption of the motor innervation. The diseases of the nerve root or nerve discussed are lateralized intervertebral disk disease, spinal cord neoplasia, malignant peripheral nerve sheath tumors, and traumatic neuropathies. The diagnosis of these diseases requires careful attention to the signalment, a complete history, and a thorough physical examination focusing on the neurologic and orthopedic components. Ancillary testing should be selected based on these results and a minimum database. Electrodiagnostic testing, radiography, and advanced imaging may help to localize the lesion more precisely and sometimes to confirm the diagnosis. Surgical exploration and histopathology often provide the definitive diagnosis. These cases of non-weight-bearing lameness are a diagnostic challenge, but when successful resolution can be reached, it is gratifying to the clinician, client, and patient.

Determinação da velocidade de condução nervosa motora dos nervos radial e ulnar de cães clinicamente sadios

O presente trabalho teve como objetivo a padronização dos valores de referência de velocidade de condução nervosa motora dos nervos radial e ulnar em cães clinicamente sadios. Para tanto, foram utilizados 30 cães, 11 machos e 19 fêmeas, sem raça definida, com idade entre dois e seis anos. Os valores médios das medidas do potencial muscular produzidos por meio de estimulação proximal e distal do nervo radial foram, respectivamente: latência inicial, 2,46+0,72ms e 1,58+0,62ms, amplitude de pico a pico, 8,79+2,26mV e 9,52+2,42mV e duração, 2,85+0,76ms e 2,71+0,75ms. Os respectivos valores do nervo ulnar foram: latência inicial, 4,17+0,53ms e 2,67+0,38ms; amplitude de pico a pico, 10,72+2,60mV e 11,72+2,81mV e duração, 2,23+0,38ms e 2,04+0,35ms. Os valores médios das medidas de velocidade de condução nervosa motora dos nervos radial e ulnar foram, respectivamente, 66,18+7,26m/s e 60,50+7,86m/s.

Assessment of organophosphorus-induced delayed neuropathy in chickens using needle electromyography

The adult chicken provides the generally accepted animal model for organophosphorus-induced delayed neuropathy, exhibiting both clinical signs and histopathological damage after exposure. In this study, noninvasive electrodiagnostic methods were used for assessment of the development of neuropathy after administration of a single dose of protoxicant tri-ortho-tolyl phosphate (TOTP, 360 and 500 mg/kg po) and active congener phenyl saligen phosphate (PSP, 2.5 and 6 mg/kg im). Onset and severity of clinical signs were dose-related for both organophosphorus compounds. Extensive peripheral nerve lesions consistent with advanced stages of organophosphorus-induced delayed neuropathy were noted in selected chickens examined 19 d after TOTP administration. Needle electromyographic examinations of gastrocnemius, anterior tibialis, semitendinosus, and semimembranosus muscles were done before exposure and on d 8, 15, and 19 after exposure to TOTP and on d 8, 15 and 17 after exposure to PSP. Untreated chickens (negative controls) were also examined at each session. An untreated chicken with a transected sciatic nerve (positive control) was examined on d 13, 20, and 23 posttransection. Prolonged insertional activities were found in both treated and untreated chickens. Denervation potentials were found in only 2 of the 20 chickens administered organophosphates. Denervation potentials were, however, easily visible 13 d following transection of the sciatic nerve of a normal chicken. Needle electromyography could not evaluate organophosphorus-induced delayed neuropathy in chickens of this study.

Indication and use of electrodiagnostic aids in neurologic disease

Electrodiagnostic aids, electromyography, auditory brainstem response testing, and electroencephalography are extensions of the neurologic examination and provide valuable information about the nervous system. This article discusses the use and interpretation of electrodiagnostic aids in equine neurology as well as the equipment that is employed. It is hoped that with a better understanding of the available electrodiagnostic aids, they will come into greater use.

Congenital and acquired neuromuscular disease of young dogs and cats

Neuromuscular disorders in small animals include a diverse group of congenital and acquired diseases. The prognosis will vary according to the disorder and the portion of the motor unit affected. A number of diseases might be satisfactorily treated (for example, myasthenia gravis, congenital myotonia), whereas others may be self-limiting (for example, hereditary myopathy of Labrador Retrievers). Accurate diagnosis is necessary for establishing a prognosis and treatment plan suitable to the patient and client. Specific diagnosis in the absence of specialized tests is difficult, although not always impossible (for example, congenital myotonia in the Chow Chow). A knowledge of the neuromuscular diseases that might affect small animals, a detailed history, and a thorough physical examination will help in the presumptive diagnosis. Specialized laboratory examinations may need to be applied (for example, antiacetylcholine receptor antibody titer for acquired myasthenia gravis). Referral may be necessary for more detailed diagnostic workup (for example, electromyographic examination, nerve or muscle biopsy examination). In the case of inherited neuromuscular disorders, a knowledge of inheritance patterns will allow genetic counseling to avoid future problem breedings.