bluuebunny/crossref_metadata_2025 huggingface dataset:
Recording characteristics of monopolar emg electrodes
Authors: Nandedkar Sanjeev D. , Sanders Donald B.
Published: January 2005

Motor unit action potentials (MUAPs) and the electromyographic (EMG) interference pattern (IP) were recorded from the biceps muscle of 5 normal subjects using both a concentric needle (CN) and a disposable monopolar needle (MN) electrode. The MUAPs recorded by the MN electrode had higher amplitude and area and were more frequently complex than those recorded with the CN electrode. The MUAP duration and area: amplitude ratio were similar for both electrodes. Although the MN electrode had a larger recording surface, its dimensions (maximum diameter and length of the cone shaped tip) were similar to those of the CN electrode (minor and major axes of the elliptical recording tip). Based on these observations, we infer that the MN electrode may be more selective than the CN electrode, ie, the AP amplitude recorded by the MN electrode decreases faster than the AP amplitude recorded by a CN electrode when the distance of the muscle fiber from the recording electrode increases. Photomicrographs of the MN electrode after use demonstrated no evidence that the insulating material had peeled off. There was also no evidence that MUAP measurement values changed during the recordings as would be expected if the recording surface changed due to peeling of the insulating material.
Uni‐ and bipolar surface recording of human nerve responses
Authors: Winkler Tomas , Stårlberg Erik , Haas Lindsay F.
Published: January 2005

Nerve conduction studies are of great clinical value in diagnosing nerve pathology and injury. In most neurophysiological laboratories nerve conduction recordings are routinely made with surface bipolar electrodes. More rarely, needle electrodes are used. A bipolarly recorded nerve action potential (NAP) is the difference between 2 unipolar NAPs recorded from each pole of a bipolar electrode and a remote reference. The delay between the 2 separated unipolar NAPs depends on the distance between the poles and the conduction velocity (CV). When the delay between the unipolar NAPs was increased (partly through simulation), the following changes of the bipolar NAP occurred: (1) total amplitude was maximal at a certain delay but decreased if the delay was shorter or longer, (2) latencies of the first positive and the first negative peaks increased slightly until their amplitudes reached maximal values, (3) a second negative peak of increasing latency appeared with longer delays, (4) latencies of later peaks increased linearly, and (5) total area increased nonlinearly. All parameters of the bipolarly recorded NAP (except the onset of the first positive phase) changed with increasing delay. The significance of this is that if NAPs are recorded with a bipolar electrode, standard values obtained for each nerve cannot be transferred between laboratories if different interelectrode (interpolar) distances are used. Furthermore, the assumption that a fixed interelectrode distance allows comparisons between reference values and patient data is incorrect.
Segregation by modality of myelinated and unmyelinated fibers in human sensory nerve fascicles
Authors: Hallin Rolf G. , Ekedahl Rolf , Frank Ove
Published: January 2005

Thin diameter concentric needle electrodes with a small recording surface were used to explore the characteristics of neighboring fibers in sensory median nerve fascicles. Fibers which were close neighbors in the fascicle, were not randomly distributed intraneurally. Instead there was an intrafascicular segregation by modality of both myelinated and unmyelinated fibers. In addition, evidence was obtained which suggested that the contents of different Schwann cells vary. Some Schwann cell systems envelop afferent C fibers whereas others hold efferent sympathetic C axons. The results imply a modality segregation amongst both A and C fibers in human peripheral sensory nerve fascicles.
Myosin expression in hypertrophied fast twitch and slow tonic muscles of normal and dystrophic chickens
Authors: Kennedy John M. , Zak Radovan , Gao Lizhu
Published: January 2005

Disruption of the developmental program of myosin gene expression has been reported in chicken muscular dystrophy. In the present report, the relationship between muscular dystrophy and the ability of muscle to respond to an increased work load with a transition in the myosin phenotype has been investigated. Hypertrophy of slow tonic anterior latissimus dorsi (ALD) and fast twitch patagialis (PAT) muscles was induced by overloading for 35 days and myosin expression was analyzed by electrophoresis and immunocytochemistry. Normal and dystrophic chicken ALD muscles have nearly identical proportions of SMhyphen;1 and SMhyphen;2 isomyosins and both exhibit an age‐related repression of the SMhyphen;1 isomyosin which is enhanced and accelerated by overloading. Immunocytochemistry with anti‐myosin heavy chain (MHC) antibodies demonstrates the appearance of nascent myofibers in overloaded ALD muscles from both normal and dystrophic chickens. A minor fast twitch fiber population is also identified which doubles in number with overloading in normal ALD muscles. There are only half as many fast twitch fibers in control dystrophic ALD muscles and this number does not increase with overloading. In contrast to ALD muscles, the isomyosin profile of normal and dystrophic PAT muscles is quite different. There is significantly more FMhyphen;3 and significantly less FMhyphen;1 isomyosin in the dystrophic PAT muscle. However, both normal and dystrophic PAT muscles exhibit an overload‐induced accumulation of the FMhyphen;3 isomyosin. Immunocytochemistry reveals that, unlike the normal PAT muscle, the dystrophic PAT muscle contains a population of myofibers which express slow MHCs. As in the ALD muscle, overload‐induced hypertrophy is associated with a repression of the SMhyphen;1 MHC in these fibers. Nascent myofiber formation does not occur in either normal or dystrophic overloaded PAT muscles.
Steroid‐responsive tubular aggregate myopathy
Authors: Gilchrist James M. , Ambler Mary , Agatiello Paul
Published: January 2005

We report a man with an acute myalgia/cramp syndrome and tubular aggregates on his muscle biopsy. He was placed on prednisone and was found to be exquisitely sensitive to the drug, with changes of only 5 mg precipitating recurrence of symptoms. He was eventually tapered off all steroids, without symptoms, and repeat biopsy showed no tubular aggregates. We recommend similar patients be given a trial of high‐dose steroids.
Electrophysiological findings in localized hypertrophic mononeuropathy
Authors: Phillips Lawrence H. , Persing John A. , Vandenberg Scott R.
Published: January 2005

Localized hypertrophic mononeuropathy (LHM) is a rare foccal neuropathy associated with perineurial cell proliferation due to an undefined stimulus. We report a case of LHM involving the proximal ulnar nerve in a 13‐year‐old boy. Serial clinical and electrophysiological observations were done, including intraoperative recordings directly from the nerve on two occasions. The evolution of abnormalities, as documented by electrophysiological and immunohistochemical studies, is compatible with a process of progressive thinning of myelin sheaths, culminating in axonal degeneration in later stages. Intraoperative recording of nerve action potentials was used to guide surgical management of the lesion. Ultimately, there was a good clinical and electrophysiological response to resection of the lesion and sural nerve fascicular grafting.
Inclusion body myositis with cricopharyngeus muscle involvement and severe dysphagia
Authors: Verma A. , Bradley Walter , Adesina A. M. , Sofferman R. , Pendlebury W. W.
Published: January 2005

A patient with inclusion body myositis (IBM) is presented. Unusual aspects of this case include a myopathy of 36 years duration, severe dysphagia due to cricopharyngeus muscle dysfunction, improvement with cricopharyngeus myotomy, and a diagnostic cricopharyngeus muscle biopsy.
Analysis of inflammatory cells and complement C3 in bupivacaine‐induced myonecrosis
Authors: Orimo Satoshi , Hiyamuta Eizo , Arahata Kiichi , Sugita Hideo
Published: January 2005

Immunohistochemical analysis of the inflammatory cells and complement C3 in the rat skeletal muscle was performed chronologically in bupivacaine‐induced myonecrosis. At 30 minutes after injection, polymorphonuclear leukocytes appeared and increased in number, with a peak value at 12 hours, while macrophages reached the highest level at 2 days. In contrast, T cells comprised only a small population. Two weeks after the injection, all types of the inflammatory cells returned to the normal level. Deposition of complement C3 was recognized at 60 minutes at the surface membrane of de erating muscle fiber. Our observation suggests the importance of both polymorphonuclear leukocytes and complement C3 in the early stage, and macrophages in the later stage of bupivacaine‐induced myonecrosis. In addition, our findings cast doubt on the pathological significance of T cells in this model.
In vivo effects of sera from Guillain‐Barré subgroups: An electrophysiological and histological study on rat nerves
Authors: Oomes Peter G. , Van Der Meché Frans G. A. , Markus‐Silvis Loes , Meulstee Jan , Kleyweg Ruud P.
Published: January 2005

Serum from 20 patients with Guillain‐Barré syndrome (GBS), 10 healthy controls and 10 patients with recent cytomegalovirus, Epstein‐Barr virus, or Campylobacter jejuni/coli infections was injected into rat sciatic nerve. The 20 GBS patients consisted of 2 groups of 10 patients with different electrophysiological and clinical disease patterns. The main aim of the study was to investigate possible differences in humoral (auto‐)immunity between these subgroups. We found no statistically significant differences in electrophysiological or histological parameters between nerves injected with sera from the 2 GBS groups. The sera of the‐GBS groups caused significantly more compound muscle action potential reduction at 3 to 5 days postinjection than the healthy control sera. No significant difference in nerve conduction was found between nerves injected with GBS serum and serum of patients with proven infections without GBS. Histological analysis of the same nerves that were studied electrophysiologically showed no significant differences in demyelination or other histological parameters between patients and controls at 5 days postinjection. Based on the findings in this study that sera of GBS groups with important differences in disease pattern and sera of patients with proven infection but without GBS show similar in vivo effects on rat nerves, we suggest it may be more likely that these effects are caused by aspecific serum factors associated with immune‐system activation, especially by precedent infections, than by specific disease‐related factors such as anti‐myelin antibodies.
Quantitative comparison of motor unit potential parameters between monopolar and concentric needles
Authors: Chan Rai Chi , Hsu Tao Chang
Published: January 2005

This study quantitatively compared the simultaneous recording of the “same” motor unit potentials recorded by closely positioned concentric and monopolar needles. The motor unit potentials from the anterior tibialis of 12 young subjects were analyzed independently by both needles being connected to 2 sets of EMG‐computer combinations. Recordings of the same motor unit potentials were confirmed by triggering and averaging of the 2 sets of motor unit potentials with identical firing patterns on both EMG screens. Automatic analysis disclosed the monopolar recordings had a significantly higher mean amplitude (2.05 times), larger surface area (2.64 times), and longer duration (1.86 times) than the concentric recordings, while the mean number of phases (1.58 times) and turns (1.35 times) revealed no statistical differences. Both active recording and reference electrodes contributed to these differences.
AAEM minimonograph #37: Facial and limb myokymia
Authors: Gutmann Ludwig
Published: January 2005

Myokymia is a clinical phenomenon associated with characteristic electromyographic activity referred to as myokymic discharges. These are spontaneously generated bursts of individual motor unit potentials with each burst recurring rhythmically or semirhythmically, usually several times per second. It involves facial muscles more commonly than those of the extremities, and is most often seen in association with Guillain‐Barré syndrome, multiple sclerosis, radiation plexopathy, pontine tumors, and timber rattlesnake envenomation. An alteration in the biochemical microenvironment of axon membranes at one of the various sites along the motor axon is the likely basis for the altered membrane excitability that underlies the myokymic discharges in most cases. The similarity of these discharges to those seen with hypocalcemic tetany, and the ability to manipulate myokymic discharges by altering serum‐ionized Ca++, suggests that decrease in the ionized Ca++ in the microenvironment of the axon may play an important role.
Effect of statistical methodology on normal limits in nerve conduction studies
Authors: Robinson Lawrence R. , Temkin Nancy R. , Fujimoto Wilfred Y. , Stolov Walter C.
Published: January 2005

Mean ± 2 standard deviations (SD), which relies on a Gaussian distribution, has traditionally been used to derive normal limits for nerve conduction studies. Our purpose was to examine skew in nerve conduction study (NCS) parameters, and to compare normal limits derived by several alternative methods. We examined 22 NCS parameters from 75 asymptomatic, nondiabetic men (controls). The coefficient of skewness (g1) was significantly positive (P < 0.10, two‐tailed test) in 5 of 8 amplitude and 6 of 8 latency measurements. Transformation reduced g1 in 19 of 22 parameters, and was optimal when g1 was closest to zero. For each measurement, ideal normal limits were defined as mean ± 2 SD of the optimally transformed data of the control subjects. The percentage of 66 diabetic subjects classified as abnormal by the raw data, but normal by the ideal normal limits, was the positive misclassification rate; while the percentage considered normal by the raw data, but abnormal by the ideal normal limits, was the negative misclassification rate. Mean ± 2 SD of the raw data produced up to 11% positive misclassifications and 12% negative misclassifications. When the range of observed values was used, up to 6% positive misclassifications and 13% negative misclassifications were found, while the 2.5 or 97.5 percentile values produced up to 10% positive misclassifications and 13% negative misclassifications. We conclude that analyses using the raw data to derive normal limits result in an unacceptable rate of misclassification. Normal limits should be derived from the mean ± 2 SD of the optimally transformed data.
Changes in nerve fiber numbers distal to a nerve repair in the rat sciatic nerve model
Authors: MacKinnon Susan E. , Dellon A. L. , O'Brien J. P.
Published: January 2005

Changes in nerve fiber numbers distal to a nerve repair in the sciatic nerve of 48 rats were evaluated over a 1‐ to 24‐month period. The results of the morphometric evaluation in the sciatic nerve distal to the nerve repair demonstrated an increase in nerve fiber counts as early as 1 month following the nerve repair. The number of nerve fibers in the distal nerve was greatest at 3 months and did not return to normal levels until 24 months. The results of this study will influence the timing of experimental studies in which nerve fiber counts are critical for evaluation, and provides a better understanding of the clinical events occurring following nerve repair.
Aaem case report #23: Acute paralytic poliomyelitis
Authors: So Yuen T. , Olney Richard K.
Published: January 2005

A 56‐year‐old man with acute paralytic poliomyelitis is described. The illness started with fever and diarrhea after an overseas trip, and an enterovirus other than poliovirus was isolated from the patient's stool. The onset of weakness was rapid and asymmetric, with primary involvement of the lower extremities. Nerve conduction studies revealed low amplitude motor responses after the first week, with normal results for sensory studies. Serial electromyographic studies were performed, documenting acute denervation followed later by reinnervation in the distribution of multiple segments. The clinical and electrodiagnostic features of acute poliomyelitis are reviewed.
Use of the photoplethysmographic technique to analyze the valsalva maneuver in normal man
Authors: Benarroch Eduardo E. , Opfer‐Gehrking Tonette L. , Low Phillip A.
Published: January 2005

We analyzed the Valsalva maneuver (VM) using a photoplethysmographic technique in 24 normal subjects. We studied the effects of test duration (range 5 to 20 seconds) and magnitude of expiratory pressure (EP, range 20 to 50 mmHg) on maximal (%Δ) and time integrated (int) changes in heart rate (HR), and mean (MAP) and pulse (PP) pressures during phases II and IV. At all EPs, there was correlation (P < 0.01) between %Δ MAP in both late phase II and phase IV and duration of the VM. The Valsalva ratio (VR) correlated with test duration only at high EPs. All responses, except the fall in MAP in early phase II and bradycardia in phase IV, correlated with EPs. The VR correlate not only with HR responses in phases II and IV but also with MAP and PP overshoot in phase IV. Correlations between maximal AP and HR changes in either phase II and IV were poor. Our study indicates that the photoplethysmographic technique allows a more rational interpretation of the VM in the clinical setting. The VR cannot be adequately interpreted without comcomitant monitoring of arterial pressure during the VM.
Quantitation of the alternate movement rate in normal and diabetic subjects
Authors: Kennedy William R. , Navarro Xavier , Stewart Nathaniel J.
Published: January 2005

Functional abnormalities of alternate movement rate (AMR) of finger and foot tapping were quantitated in 162 patients with diabetic neuropathy and 30 control subjects using a simple electronic device. The quantitative AMR (QAMR) averaged 29.5 ± 3.0 for finger tapping and 20.4 ± 3.7 for foot tapping in controls, and 27.5 ± 4.8 (P < 0.05) and 17.0 ± 5.6 (P < 0.005) for finger and foot, respectively, in diabetic patients. Fifty‐one patients had abnormal QAMR in the finger and 79 in the foot. The QAMR values correlated with the results of nerve conduction studies of patients. Testing for abnormalities of AMR is a useful addition to the testing of dysfunction secondary to diabetic neuropathy. It provides quantitation of a common, subject‐initiated, functional task more accurately than possible by clinical observation.
Peripheral sensory abnormalities in patients with multiple sclerosis
Authors: Shefner Jeremy M. , Carter Jonathan L. , Krarup Christian
Published: January 2005

Although multiple sclerosis primarily affects myelin within the central nervous system, both pathologic and physiological studies suggest that mild deficits in peripheral nervous system myelin may be common. To evaluate this question further, we performed near nerve studies on sural nerves of 14 patients with multiple sclerosis. Peak‐to‐peak amplitude and maximum conduction velocity were normal in 9 of 14 patients, while minimum conduction velocity, or the velocity of the slowest‐conducting component of the sensory action potential, was abnormally reduced in 9 patients. In addition, the supernormal period was evaluated for patients and compared with a control sample; multiple sclerosis patients showed a significant reduction in the amplitude of supernormality. Both the reduction in minimum conduction velocity and the alteration in the supernormal period are consistent with a mild defect in peripheral myelin.
A study of motor unit structure by means of scanning EMG
Authors: Gootzen Theis H. J. M. , Vingerhoets Dick J. M. , Stegeman Dick F.
Published: January 2005

We used the scanning EMG technique to investigate the structure of human quadriceps muscle motor units. A group of healthy volunteers and 2 groups of patients with proven neurogenic or myogenic neuromuscular pathology have been studied. In total, 86 scans were obtained. An estimate of the motor unit territory (S) separates the 2 patient groups: the majority of territories of myogenic patients are smaller than 4 mm, whereas almost all motor unit territories of neurogenic patients are larger. However, the sizes of the pathologic units only occasionally exceed the upper and lower limits of normal units (2 to 8 mm). The myogenic scans show, on average, a much larger temporal dispersion (T) between the MUAPs within a motor unit than the normal scans. These findings are in accordance with observations with the same technique by others. For the neuropathic scans, there is a significant positive correlation between S and T, which is completely absent in myopathic scans. These observations are confronted with current morphometrical knowledge on motor unit physiology and anatomy.
Long‐term electrical stimulation of muscles in children with duchenne and becker muscular dystrophy
Authors: Zupan Anton
Published: January 2005

Nine children suffering from progressive muscular dystrophy (7 Duchenne and 2 Becker) were included in a program of low‐frequency electrical stimulation (LFES) of the right tibialis anterior (TA) muscle. Muscle strength and muscle fatigue were estimated by measuring torques in the ankle during attempts of maximal voluntary contraction (MVC) in the direction of dorsal flexion of the foot and during electrically evoked contractions (EEC). No important increase in the strength of the stimulated muscles was noticed in 4 boys whose muscles were stimulated for 3 months. The muscles of 5 boys who were subjected to electrical stimulation for 9 months showed an improvement; 6 measurements made during the stimulation program revealed that changes of torques in the ankle of the right stimulated extremity were significantly different (P < 0.001) from the changes of torques in the ankle of the left nonstimulated extremity.
A unique case of reducing body myopathy
Authors: Nomizu Simone , Person Donald A. , Saito Coswin , Lockett L. John
Published: January 2005

The clinical, electromyographic, and histologic characteristics of a 17‐year‐old girl with reducing body myopathy are described. She is, to our knowledge, the oldest reported case and the only patient described with severe mitral valve prolapse and scoliosis. Electromyography demonstrated spontaneous positive sharp waves and fibrillation potentials with many lowamplitude, short, polyphasic motor unit potentials. The right deltoid muscle was chaacterized by focal areas with large fibers associated with increased endomysial connective tissue and “split” fibers. Purple‐gray sarcoplasmic masses stained with trichrome were PAS‐negative, appeared as “empty” spaces with both ATPase and NADH‐TR, and stained darkly with menadione NBT. The features described expand the clinical presentation of this myopathy, and may lead to a better understanding of its etiology.
Adhesion in skeletal muscle during regteneration
Authors: Hurme Timo , Kalimo Hannu
Published: January 2005

Adhesion molecules were studied in regenerating skeletal muscle immuno‐histochemically and ultrastructurally after a standardized trauma. In normal muscle, extracellular matrix (ECM) protein tenascin was restricted to myo tendinous junctions (MTJ), while the integrin β1‐subunit was present also on the sarcolemma. After injury, tenascin increased on the outer surface of regenerating myofibers, where cellular fibronectin also accumulated. Later tenascin concentrated at the tips of regenerating myofibers, where new MTJs were formed. The β1‐subunit disappeared on necrotized myofibers aqnd reppeared on regenerating fibers in a thicker layer. The regener ating myofibers were invested by a basaql iamina, except, for the growth cones at the distal ends, which were laminin‐nehative until the formation of MTJs occured. These results indicate that regenerating muscle cells are attached to the ECM in a way that allows both growth of the muscle cells across the scar and their use before the regeneration is completed.
Changes in mast‐cell distribution in skeletal muscle after denervation
Authors: Sánchez‐Mejorada Gabriela , Alonso‐deFlorida Francisco
Published: January 2005

Motor nerves are known to govern the structure of skeletal muscle. In the normal guniea pig diaphragmatic muscle, we found that mast cells were predominatly located in the central tendon. Following denervation, these cells became more numerous in the muscle itself than in the tendon. There fore, nervous trophic influences are exerted on other tissue elements besides those which sustain transmission and contraction. Ascertaining mastcell distribution in biopsies may help to elucidate denervation effects in motor neuron diseases.
Perioral reflexes in orofacial dyskinesia and spasmodic dysphonia
Authors: Topka Helge , Hallett Mark
Published: January 2005

In order to assess the clinical utility of trigemino‐facial reflexes in lower facial muscles, we studied perioral reflexes to mechanical and electrical stimulation in 13 patients with spasmodic dysphonia and orofacial dyskinesia and in 7 healthy subjects. Mechanical stimulation of the upper lip of the all patients and electrical stimulation of the infraorbital nerve of patients with orofacial dyskinesia elicited larger perioral reflexes than in controls. In the majority of patients, hyperexcitable perioral were accompanied by increased gain of the blink reflex. In 4 patients, however, trigemino‐facial reflexes were enhanced selectively in either the perioral muscles or orbicularis oculi. Our findings suggest that the quantitive assessment of perioral reflexes may provide information about the excitability of brainstem interneurons in cranial dystonia that is complementary to blink reflex studies. © John Wiley & Sons, Inc.
Dermatomal somatosensory evoked potentials in the diagnosis of lumbosacral spinal stenosis: Comparison with imaging studies
Authors: Snowden Marion L. , Haselkorn Jodie K. , Kraft George H. , Bronstein Andrew D. , Bigos Stanley J. , Slimp Jefferson C. , Stolov Walter C.
Published: January 2005

Dermatomal somatosensory evoked potentials (DSEPs) and computerized tomography/magnetic resonance (CT and/or MR) images were retrospectively analyzed to evaluate their relationship in the diagnosis of lumbosacral spinal stenosis (SS). Of 155 patients referred for DSEPs with a clinical suspicion of lumbosacral SS, 58 met the inclusion criteria. DSEP abnormality was defined as: (1) N1 latency absent or >2.5 SD; (2) side‐to‐side latency difference >2 SD; (3) amplitudes > 2 SD below the mean; or (4) amplitude ratio >2 SD. Involvement of two or more DSEP levels by any of the above criteria was labeled multiple root disease (MRD). Involvement of one level was labeled single root disease (SRD). Images were reviewed independently by a neuroradiologist. Results revealed 54 subjects with SS by imaging; 42 had MRD and 8 had SRD by DSEPs. Sensitivity for MRD and SS was 78% and for MRD plus SRD and SS was 93%. © 1992 John Wiley & Sons, Inc.
The spectrum of concentric macro EMG correlations. Part II. Patients with diseases of muscle and nerve
Authors: Gan Richard , Jabre Joe F.
Published: January 2005

In the second part of this study we investigate the correlations between the concentric and conmac action potentials in motor units of individuals with diseases of muscle and nerve. We studied 86 myopathic and 86 neurogenic motor units and compared their concentric and conmac action potentials. In the patients with myopathy, we found that the concentric motor unit action potential's (MUAP) area correlates strongly with the conmac potential, even better than in normals, while its amplitude correlates less. In the neurogenic group, we found that both the concentric MUAP's area and amplitude correlated very well with their conmac counterpart, more so than in normals. Thus, in pathology, as in normals, measuring the concentric MUAP's area in addition to its amplitude adds to the diagnostic sensitivity of motor unit potential measurements. These findings are discussed in light of the known dynamic and architectural motor unit changes which take place in the myopathic and neurogenic motor unit. © 1992 John Wiley & Sons, Inc.
Differential expression of muscular dystrophy in diaphragm versus hindlimb muscles of mdx mice
Authors: Dupont‐Versteegden Esther E. , McCarter Roger J.
Published: January 2005

Contractile properties of diaphragm (DIA) from mdx and control mice were compared with those of hindlimb muscles [soleus (SOL) and extensor digitorum longus (EDL)] in vitro. Mice ranged in age from 2 weeks to 1.5 years. Muscles were directly stimulated and properties measured were: contraction time, half‐relaxation time, active tension per unit area, fatigue index, and maximal velocity of shortening (Vmax). Active tension decreased significantly with age in mdx DIA but not in control DIA. SOL and EDL active tensions were less in mdx than control over the whole age range and did not decrease with age. Vmax was decreased in mdx DIA, but not in mdx SOL or EDL. These results demonstrate that DIA is more affected by muscular dystrophy than hindlimb muscles. Since many Duchenne patients exhibit respiratory distress, this differential expression of dystrophy in diaphragm, as compared to limb muscles, may have important clinical implications. © 1992 John Wiley & Sons, Inc.
Flavivirus induces MHC antigen on human myoblasts: A model of autoimmune myositis?
Authors: Bao Shisan , King Nicholas J. C. , Dos Remedios Cristobal G.
Published: January 2005

Infection of human embryonic myoblasts by West Nile virus (WNV), a flavivirus, caused significant upregulation of class I and II MHC expression as determined by flow cytometry. After 48 hours at a multiplicity of infection of 5 pfu/cell, a sixfold increase in MHC class I expression was induced from initially low levels of expression. In contrast, MHC class II was induced de novo to five times the control fluorescence level. At least 70% of the cells were infected as determined using fluorescence microscopy and anti‐WNV antibody labeling. Myoblasts were > 90% pure as shown by anti–Leu‐19 labeling. MHC class I (but not class II) was increased threefold after exposure to virus‐inactivated supernatant from 48‐hour–infected cells, indicating the presence of factor(s) contributing to the MHC class I increase. These findings may be important in establishing a link between viral infection of human cells and induction of inflammatory autoimmune disease. We discuss the possibility of using WNV as an in vivo model. © 1992 John Wiley & Sons, Inc.
Sensory testing versus nerve conduction velocity in diabetic polyneuropathy
Authors: Redmond Janice M. T. , McKenna Malachi J. , Feingold Marcia , Ahmad B. K.
Published: January 2005

We sought to evaluate the utility of quantitative sensory testing (QST) and nerve conduction velocity (NCV) studies as measures of distal symmetric polyneuropathy (DSP). We studied 36 diabetic patients divided into four clinical categories of increasing severity. QST included thermal testing and vibration thresholds. NCV studies included median, peroneal, and sural nerves. Results of QST and NCV were compared among clinical groups using survival methodology. The log‐rank statistic showed significant differences among the groups; the direction of the differences were consonant with clinical severity. For each diabetic patient, the result of each measurement was classified as normal or abnormal; more diabetic patients had abnormal NCV than either vibration tests or thermal tests. In conclusion, findings of QST and NCV are in keeping with clinical categorization of patients, QST and NCV are complementary tests, and the sural sensory study is the best single predictor of DSP. © 1992 John Wiley & Sons, Inc.
Recurrent potentials in human peripheral sensory nerve: Possible evidence of primary afferent depolarization of the spinal cord
Authors: Shefner Jeremy M. , Buchthal Fritz , Krarup Christian
Published: January 2005

To study slowly conducted components of the orthodromic compound sensory action potential (CSAP), the response evoked at the lateral malleolus in the sural nerve was recorded through near‐nerve needles at two to four sites along the nerve at midcalf. When 500 to 2000 responses were averaged at high gain, components with latencies of 30 to 80 ms were often recorded. In contrast to the main component and late components with latencies of less than 15 to 20 ms, the latencies of these extremely late components diminished the closer to the spinal cord that they were recorded. This suggested that the components were conducted antidromically from proximal to distal. This assumption was supported by abolishing the components by local anesthesia of the nerve proximal to the recording electrodes. These antidromic potentials therefore appear to be due to recurrent discharges in the sural nerve. Recurrent discharges were recorded from 65% of 60 subjects (18 normal subjects and 42 patients with peripheral or central nervous system disorders). The latencies of the recurrent discharges allowed conduction to and back from the spinal cord. Although the origin of these potentials remains unknown, we suggest that they are due to dorsal root reflexes within the spinal cord. In this case, the responses may be a direct expression of primary afferent depolarization (PAD) seen in pre‐synaptic inhibition, and may be of value in further studies on the physiology and pathophysiology of presynaptic inhibition of cutaneous fibers in man. © 1992 John Wiley & Sons, Inc.
A case of myopathy associated with a dystrophin gene deletion and abnormal glycogen storage
Authors: Rose Michael R. , Howard Robin S. , Genet Sally A. , McMahon Catherine J. , Whitfield A. , Morgan‐Hughes John A.
Published: January 2005

A 30‐year‐old man with no family history of muscle disease presented with a progressive proxirnal myopathy and calf hypertrophy characteristic of Becker muscular dystrophy. A deletion of exons 45 to 48 in the dystrophin gene was confirmed by Southern blotting and multiplex polymerase chain reaction. However, muscle biopsy showed massive accumulation of glycogen, although no significant abnormality of glycolytic pathway enzymes could be demonstrated. This patient therefore has a previously undescribed myopathy associated with both Becker muscular dystrophy and a glycogen storage disorder of unknown aetiology. © 1993 John Wiley & Sons, Inc.
AAEM minimonograph #2: Important anomalous innervations of the extremities
Authors: Gutmann Ludwig
Published: January 2005

Anomalous innervations of the extremities are common and influence the interpretation of electrophysiologic studies in normal patients and those with peripheral nerve lesions. The following anomalous innervations are reviewed: median to ulnar nerve communication; ulnar to median nerve communication; variations in the innervation of intrinsic muscles of the hand; accessory deep peroneal nerve; and tibial to peroneal nerve communication. The electrophysiologic recognition of these anomalies and the manner in which they affect the interpretation of electrodiagnostic studies in various conditions is emphasized.
Mechanoreceptors in human myotendinous junction
Authors: Jozsa Laszlo , Balint Jozsef , Kannus Pekka , Järvinen Markku , Lehto Matti
Published: January 2005

The sensory‐nerve‐ending system of 40 myotendinous junctions of human palmaris longus and plantaris muscles was studied histologically. All the known four types of nerve endings were identified. The Ruffini corpuscles could be found in equally small numbers (one to five) in both the muscular and tendineal sites of the junction. Also the free nerve endings were distributed equally on both sites. The Pacini corpuscles were frequent in the tendineal site (six to 14), but rare in the muscular site (one to three). The Golgi tendon organs were, in turn, frequent in the muscular site (nine to 12) but rare in the tendineal site (one to four), respectively. Within the muscle and tendon parts of the junction, the distance between two mechanoreceptors was always more than 250 m̈m and the receptor distribution was homogeneous. Further studies are needed to give functional explanation for these anatomic findings. © 1993 John Wiley & Soncs, Inc.
Immunohistochemical characteristics of polymyositis in patients with HTLV‐1–associated myelopathy and HTLV‐I carriers
Authors: Higuchi Itsuro , Montemayor Elizabeth S. , Izumo Syuji , Inose Masaru , Osame Mitsuhiro
Published: January 2005

The immunohistochemical characteristics of polymyositis in patients with HTLV‐I‐associated myelopathy (HAM) and HTLV‐I carriers were studied. Infiltrating cells were predominantly T cells and were not different from in the control group. All specimens contained positively staining muscle fibers for MHC class I antigens, but class II antigens were also expressed in some muscle fibers in 1 patient with HTLV‐I‐negative polymyositis, 3 patients with HTLV‐I‐positive polymyositis, and all 5 HAM patients with polymyositis. Expression of the neural cell adhesion molecule was lowest in the HAM patients. These findings may suggest a different immune environment in polymyositis with HAM. © 1993 John Wiley & Soncs, Inc.
Association of IgG anti‐GD1a antibody with severe Guillain–Barré syndrome
Authors: Yuki Nobuhiro , Yamada Mitsunori , Sato Shuzo , Ohama Eisaku , Kawase Yasuhiro , Ikuta Fusahiro , Miyatake Tadashi
Published: January 2005

We earlier reported cases of 2 patients with severe acute Guillain–Barré syndrome (GBS) associated with high‐IgG anti‐GD1a antibody titer. We now have investigated the autoantibody against GD1a or GM1 in 37 GBS patients using the enzyme‐linked immunosorbent assay and have found a statistically significant association between IgG anti‐GD1a antibody and the severity of the disease (need of a respiratory for more than 1 month and a poor functional prognosis 3 months after neurologic onset). An autopsy which showed severe GBS associated with IgG anti‐GD1a antibody produced the following findings: (1) severe axonal degeneration and segmental demyelination of peripheral nerves; (2) lymphocytic infiltration; and (3) marked central chromatolysis of the lower motoneurons. © 1993 John Wiley & Sons, Inc.
Effect of denervation on overdevelopment of chloroquine‐induced autophagic vacuoles in skeletal muscles
Authors: Kumamoto Toshihide , Ueyama Hidetsugu , Watanabe Susumu , Murakami Tatsufumi , Araki Shukuro
Published: January 2005

We studied how denervation affects the overdevelopment of autophagic vacuoles in muscles of chloroquine‐treated rats. The number of autophagic vacuoles increased significantly in the chloroquine‐treated soleus muscles after denervation as compared to similarly treated contralateral, innervated muscles. No vacuoles were present in the denervated and innervated muscles of saline‐treated rats. After denervation, the autophagic vacuoles in chloroquine‐treated muscle contained numerous glycogen particles and various heterogeneous materials. A biochemical study showed no significant difference in the activities of lysosomal proteases and hydrolases in the chloroquine‐ and salinetreated muscles after denervation, although these activities were markedly increased in comparison to the same activities in the contralateral, innervated muscles. Chloroquine treatment by itself did not, but denervation with or without chloroquine treatment did enhance the biochemical activities of lysosomal enzymes in the animals. We speculate that denervation induces the marked accumulation of autophagic vacuoles in chloroquine‐incuced myopathy.
Vocal cord paralysis: Clinical and electrophysiologic features
Authors: Simpson David M. , Sternman David , Graves‐Wright Janet , Sanders Ira
Published: January 2005

Vocal cord paralysis may occur in isolation or as part of a constellation of findings in neurological disease. We investigated the pathophysiology of these disorders with laryngeal electromyography (LEMG). We studied 44 patients with idiopathic vocal cord paralysis, confirmed by laryngoscopy. The major LEMG finding, present in 29 vocal cords, was evidence of active or chronic denervation in the thyroarytenoid (TA), indicating recurrent laryngeal neuropathy. Denervation of the cricothyroid (CT) in 5 patients indicated superior laryngeal neuropathy. TA and CT involvement in 1 patient indicated proximal laryngeal or vagus nerve damage. LEMG was performed in 48 patients with other laryngeal disorders. LEMG proved to be a safe and effective procedure in the diagnosis of laryngeal neuropathy as distinguished from supranuclear and mechanical disorders of the larynx. © 1993 John Wiley & Sons, Inc.
Motor unit number estimation, isometric strength, and electromyographic measures in amyotrophic lateral sclerosis
Authors: Bromberg M. B. , Forshew D. A. , Nau K. L. , Bromberg J. , Simmons Z. , Fries T. J.
Published: January 2005

Pathologic progression in amyotrophic lateral sclerosis (ALS) results from motor neuron death, while the clinical expression also reflects the compensatory effects of collateral reinnervation consequent to lower motor neuron loss. In a cross‐sectional study of ALS subjects, we made comparisons between motor unit number estimation (MUNE) values and several measures reflecting collateral reinnervation, including isometric strength, compound muscle action potential (CMAP) amplitude, surface motor unit action potential (S‐MUAP) amplitude, fiber density (FD), macro‐EMG potential amplitude, turns‐to‐amplitude (T/A) ratio, and amplitude and recruitment pattern of low threshold voluntary motor units in elbow flexor muscles. Before comparisons were made, testretest reproducibility of these measures was assessed in ALS subjects, and is highest for isometric strength, and lower but similar for EMG measures. When the effects of multiple comparisons are considered, borderline significant correlations are found between MUNE values and isometric strength. Neither MUNE values nor isometric strength are significantly correlated with macro‐EMG amplitude, FD, T/A ratio, or amplitude and recruitment rate of low threshold voluntary motor units. There are significant correlations of CMAP and S‐MUAP with MUNE values, but these are statistical artifacts with no independent interpretation. We conclude that collateral reinnervation prevents isometric strength and EMG measures from accurately reflecting lower motor neuron death in ALS. MUNE measurements are better suited to provide insight into the true natural history of the disease process and may be clinically useful to follow progression and response in drug trials. © 1993 John Wiley & Sons, Inc.
Somatosensory evoked potentials induced by stimulating a variable number of nerve fibers in rat
Authors: Zhao Shurun , Kim Daniel H. , Kline David G. , Beuerman Roger W. , Thompson Hilary W.
Published: January 2005

Somatosensory evoked potentials (SEPs) were recorded from rat spinal cord (sSEPs) and cerebral cortex (cSEPs). Stimulus sites included either one or both sural nerve branches having different fiber populations (group A), or distal to a lesion of controlled size of the sural nerve made 1 week earlier (group B). In the two groups of animals, amplitudes of SEPs correlated with the quantity of large myelinated nerve fibers. Peak latencies of sSEPs in group A related to the ratio of sizes of transmitting fibers. sSEPs and cSEPs in both groups A and B could be recorded in a reproducible fashion by stimulating sural nerve branches or lesioned nerve trunks containing only 100 or less nerve fibers greater than 4 m̈m in size. Thus, presence of sSEPs or cSEPs after stimulation distal to a lesion site does not insure that many nerve fibers have continuity with the central nervous system (CNS). © 1993 John Wiley & Sons, Inc.
Predictive value of nerve conduction measurements at the carpal tunnel
Authors: Nathan Peter A. , Keniston Richard C. , Meadows Kenneth D. , Lockwood Richard S.
Published: January 2005

We compared the predictive values of three measurements of sensory conduction of the median nerve at the carpal tunnel (maximum latency difference [MLD], 8‐cm latency [S8], and 14‐cm latency [S14]) in 2334 hands of industrial workers, workers' compensation patients, and students, The MLD was determined by the centimetric technique. The MLD was the most sensitive and efficient measurement for predicting carpal tunnel syndrome (CTS). An MLD ≥ 0.40 ms correctly identified 86.3% of 753 hands with CTS. The MLD correlated best with CTS and with the primary diagnostic category (CAT). MLD was the second factor selected in stepwise regression analysis for CAT (numbness was first and S8 was third). The MLD was the most important factor for predicting persistent or de novo CTS in a 5‐year follow‐up of 630 hands. Thus, the MLD was the most reliable nerve conduction study measurement for predicting current or future CTS in these subjects' hands.
The influence of dose of microspheres on nerve blood flow, electrophysiology, and fiber degeneration of rat peripheral nerve
Authors: Kihara Mikihiro , Zollman Paula J. , Schmelzer James D. , Low Phillip A.
Published: January 2005

Microsphere embolization of peripheral nerve results in a variable degree of ischemic fiber degeneration. To enhance the utility of the model, we evaluated the relationship between dose of microspheres to the supplying arteries of the sciatic‐tibial nerve to nerve blood flow (NBF), electrophysiology, morphology, and behavioral changes. There was considerable variability in the effect of embolization on nerve pathology in individual nerves. However, the dose of microspheres regressed with the degree of hindlimb paresis, reduction in NBF, degree of fiber pathology, and ischemic conduction failure of the tibial nerve, evaluated at day 7. All nerves with severe (grade 4) fiber degeneration had flows of < 3mL · 100g‐1 · min‐1. We conclude that it is possible to predict with a high degree of accuracy the severity of fiber degeneration by the degree of NBF reduction and by the electrophysiologic abnormalities. © 1993 John Wiley & Sons, Inc.
Antiganglioside antibodies do not necessarily play a role in multifocal motor neuropathy
Authors: Parry Gareth John Glyn
Published: January 2005

Multifocal motor neuropathy (MMN) is a disorder with a highly characteristic clinical picture and one which is defined by a specific electrodiagnostic abnormality, namely, multifocal conduction block which is confined to motor axons. Sensory axons which traverse segments of severe or even complete motor conduction block conduct normally. A proportion of patients with MMN also have elevated levels of antibodies to GM1 ganglioside. However, about one half of MMN patients lack elevated levels of these antibodies and many others have only modest elevations, to a degree often seen in other neurological and even non‐neurological disorders. Furthermore, clinical and electrophysiological improvement of MMN in response to treatment with high dose intravenous immunoglobulin is achieved in the absence of any change in antiglycolipid levels. Injection of serum from patients with MMN and elevated GM1 antibody levels produces demyelination in recipient rat nerves, suggesting a pathogenetic role for these antibodies in demyelination. However, sera of patients with identical antibody liters in other motor system diseases produced no demyelination, suggesting that the demyelinating factor resides in some other serum fraction. At present, there is insufficient evidence to support the contention that these antibodies play a critical pathogenetic role in MMN. Until more evidence is available it is important to define MMN on the basis of a characteristic clinical picture and a unique electrodiagnostic abnormality rather than on a pattern of serum antibodies. © 1994 John Wiley & Sons, Inc.