bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophysiological changes in the acute “axonal” form of Guillain–Barre syndrome
Authors: Brown William F. , Feasby Thomas E. , Hahn Angelika F. 
Published: January 2005

AbstractThe acute “axonal” form of Guillain—Barre syndrome is characterized by rapid progression to severe widespread paralysis and respiratory dependence within 2–5 days of the onset of weakness with very poor and delayed recovery. In 3 cases studied within the first 7 days, the maximum thenar, hypothenar, tibialis anterior, and extensor digitorum bervis “M” potentials were either very reduced in size or absent in response to stimulation at the usual most distal sites of stimulation at the wrist, fibular head, and/or ankle. In the latter instances, advancing the site of stimulation closer to the motor point often evoked an M response. Furthermore, continued distal advance of the site of stimulation evoked progressively larger sized M potentials. Over succeeding days even these very distally evoked M potentials. Maximum conduction velocities in motor nerve fibers just prior to total loss of excitability were often very reduced. The pattern in these cases is most consistent with progressive loss of excitability and conduction in nerve fibers undergoing axonal degeneration, although coexisting primary demyelination in the terminal segment could not be excluded as the basis for the sometimes very slowed conduction velocities. © 1993 John Wiley & Sons, Inc.
Patterns of sensory nerve conduction abnormalities in demyelinating and axonal peripheral nerve disorders
Authors: Bromberg Mark B. , Albers James W. 
Published: January 2005

AbstractThe pattern of an abnormal median‐normal sural (AMNS) sensory response is associated with acute and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP) and considered unusual in other types of neuropathy, although specificity and sensitivity of this pattern have not been evaluated. We compared sensory responses (patterns and absolute values) in patients with AIDP, CIDP, diabetic polyneuropathy (DP), and motor neuron disease (MND). Using strict criteria, the AMNS pattern occurred more frequently in recent onset AIDP (39%) compared with CIDP (28%), DP (14%–23%), or MND (22%) patients. This pattern was found in 3% of control subjects. The extreme pattern of an absent median‐present sural response occurred only in AIDP and CIDP patients and in no other groups. Abnormalities of both nerves were more common in long‐standing polyneuropathies such as CIDP and DP compared with AIDP or MND. Median nerve amplitudes were reduced significantly in AIDP, CIDP, and DP patients compared with MND patients, whereas sural nerve amplitudes were significantly reduced only in DP and CIDP patients. These findings may reflect early distal nerve involvement particularly in AIDP patients which is highlighted by differences in median and sural nerve recording electrode placement. We conclude that, in the appropriate clinical setting, the AMNS pattern, an absent median‐present sural response pattern, or a reduced median amplitude compared with the sural amplitude supports a diagnosis of a primary demyelinating polyneuropathy. © 1993 John Wiley & Sons, Inc.
Sensory potentials evoked by magnetic stimulation of the cervical spine
Authors: Zwarts Machiel J. 
Published: January 2005

AbstractMagnetic stimulation of cervical spinal roots was shown to elicit sensory potentials (MESP) which could easily be recorded at the fingers with ring electrodes. The latency of the MESP recorded at digit I was significantly shorter and the amplitude higher than of digits III and V. The latencies were largely independent of stimulus strength. In an attempt to localize the place of depolarization, the latencies of these potentials were compared with the N11 of the SEP (reflecting the arrival in the spinal cord) and with F‐wave latencies and motor evoked potentials (MEP) to abductor pollicis brevis. The MESP latencies showed a very constant difference with the N11, being 0.6 ms faster. The mean difference between F latency and MEP was 1.2 ms. It is concluded that the origin of these MESPs is very near the spinal foramina, possibly in the sensory ganglia. © 1993 John Wiley & Sons, Inc.
Anomalous origin of the sural nerve in a patient with tibial—common peroneal nerve anastamosis
Authors: Phillips Lawrence H. , Morgan Raymond F. 
Published: January 2005

AbstractRecognition of anomalous innervation patterns may be important in dealing with peripheral nerve injuries. We describe a patient who suffered injury to the common peroneal nerve (CPN) at the knee when he laterally dislocated his knee. Intraoperative nerve conduction studies during surgical exploration revealed that nerve fibers from the tibial nerve crossed over to join the CPN immediately distal to a neuroma incontinuity. The sural nerve was also found to arise totally from the CPN. © 1993 John Wiley & Sons, Inc.
Deriving reference values in electrodiagnostic medicine
Authors: Campbell William W. , Robinson Lawrence R. 
Published: January 2005

AbstractTraditional methods for determining nerve conduction reference values have usually involved studying a group of normal controls, and determining the mean ± 2 standard deviations (SD) for each parameter. Recent studies suggest other factors should be taken into account. Height has a greater effect on conduction velocity than age or temperature. The common assumption that conduction values follow a normal, bell‐shaped Gaussian distribution appears unwarranted. The curve for some conduction parameters is significantly skewed, making a mean ± 2 SD definition of normality inaccurate to a clinically important degree. In developing and using reference values one should consider height, age, and temperature, and calculate the mean ± 2 SD of the transformed data to remove the effects of skew. Reference values provide only a guide to the probability a given result came from a healthy or diseased individual; one should therefore seek multiple internally consistent abnormalities before diagnosing disease on the basis of electroneurography. © 1993 John Wiley & Sons, Inc.
Single fiber electromyography in myasthenia gravis during pregnancy
Authors: Massey Janice M. , Sanders Donald B. 
Published: January 2005

AbstractWe report the use of single fiber electromyography (SFEMG) to demonstrate changes in the physiologic abnormality of myasthenia gravis (MG) during pregnancy. A 23‐year‐old became pregnant 15 months after the onset of mild ocular weakness. On initial evaluation, SFEMG jitter measurements demonstrated a slight abnormality of neuromuscular transmission. There was no change in severity of clinical disease or jitter measurements until the third trimester, when she improved. Jitter measurements at that time were normal. Labor was normal and she delivered a normal male. Three days postpartum, myasthenic weakness recurred temporarily and jitter measurements showed worsening. At 16 days and 6 weeks postpartum, she had only minimal medial rectus weakness and jitter studies were normal. Three months postpartum, ocular symptoms recurred and jitter measurements were slightly abnormal. She continued to worsen, developing limb muscle and severe ocular muscle weakness at 4 months postpartum. She was treated with plasma exchange and thymectomy. Prednisone was added 2 months after thymectomy due to continued worsening and development of oropharyngeal weakness. Three years postpartum she was taking prednisone 10 mg every other day and had only slight weakness of neck flexors, and jitter studies were again normal. © 1993 John Wiley & Soncs, Inc.
Carnitine palmitoyl transferase deficiency in malignant hyperthermia
Authors: Vladutiu Georgirene D. , Hogan Kirk , Saponara Isora , Tassini Lawrence , Conroy Jeffrey 
Published: January 2005

AbstractThe activity of carnitine palmitoyl transferase, an enzyme that catalyzes the transport of long‐chain acylcarnitines into mitochondria, was quantitated in EB‐virus‐transformed lymphoblasts from 7 patients with susceptibility for malignant hyperthermia. Immunoreactive enzyme protein was also measured using an enzyme‐linked immunosorbent assay. Cell lines derived from patients with carnitine palmitoyl transferase deficiency of muscle and from normal individuals were used as positive and negative controls, respectively. One patient with malignant hyperthermia had a deficiency in the enzyme activity which was comparable with that of the known carnitine palmitoyl transferase deficient patients. This individuaľs lymphoblasts were also deficient in immunoreactive enzyme protein. All of the remaining patients with malignant hyperthermia were deficient only when the backward assay for carnitine palmitoyl transferase was used for quantitation. It is likely that a subset of individuals with a malignant hyperthermia phenotype have a primary deficiency of carnitine palmitoyl transferase and that others have a milder enzyme deficiency secondary to the primary defect in malignant hyperthermia. © 1993 John Wiley & Soncs, Inc.
Giant somatosensory evoked potentials in a patient with the anterior spinal artery syndrome
Authors: Triggs William J. , Beric Aleksandar 
Published: January 2005

AbstractWe studied a previously healthy 25‐year‐old woman with the anterior spinal artery syndrome, a rare thoracocervical myelopathy with multiple potential etiologies. Quantitative and clinical sensory examination showed dissociated loss of pin‐prick and temperature discrimination below the level of the lesion, with normal light touch, vibratory, and position sense. Magnetic resonance imaging was consistent with cervical spinal cord infarction. Median SEPs showed normal Erb's potential with absent spinal N—13 and normal scalp N—20 latency. Tibial SEPs showed normal lumbosacral responses and normal scalp P—30 latency. Both median and tibial nerve stimulation produced cortical responses of unusually large amplitude (median 38 m̈V, tibial 17 m̈V). We hypothesize that large SEP amplitudes in this patient resulted from loss of anterolateral inhibitory influences on the dorsal column–medial lemniscal system. © 1993 John Wiley & Soncs, Inc.
Muscle fiber conduction velocity changes with length
Authors: Trontelj Jože V. 
Published: January 2005

AbstractWhile recording activity from individual muscle fibers by single fiber EMG (SFEMG), stimulated either through their axons or directly, the length of the recorded muscle fiber was changed—stretched or made shorter—by manipulating the recording needle or by passive joint movements. This resulted in significant changes of latency corresponding to an increase in propagation velocity on shortening of the muscle fiber and to a slowing of its lengthening. The maximum increase in velocity was estimated to 33% and slowing to about 22%. These lengthdependent changes of muscle fiber propagation velocity are suggested to contribute to the supernormal phase of propagation velocity recovery function and to be responsible for an important part of the myogenic, interdischarge interval‐dependent, jitter. © 1993 John Wiley & Soncs, Inc.
Potassium channels from normal and denervated mouse skeletal muscle fibers
Authors: Escobar Ariel L. M. , Schinder Alejandro F. , Biali Fabian I. , Siri Leonardo C. Nicola , Uchitel Osvaldo D. 
Published: January 2005

AbstractThe properties of singles K+ channels in normal and denervated muscles were compared using the “patch‐clamp” technique. Single channels were recorded from vesicles obtained by stretching bundles of normal and denervated extensor digitorium longus (EDL) muscles. The most frequently observed channel in normal muscles was a high conductance (266 pS) Ca++ activated K+ channel. Although channel density, as estimated by patch recording, showed a significant decrease in denervated muscles, no differences were found in conductance and gating properties. Another voltage‐dependent K+ channel (81 pS) was only recorded from normal muscles, but never from denervated ones. In addition, a 35 pS conductance was recorded from both normal and denervated fibers. This channel displayed neither voltage dependence nor sensitivity to tetraethylammonium (TEA). In contrast, another TEA‐insensitive (16 pS) channel was recorded only from denervated muscles. We conclude that denervation induces significant changes in the distribution and expression of K+ channels in mammalian skeletal muscles. © 1993 John Wiley & Sons, Inc.
Lambert–Eaton myasthenic syndrome with prominent postexercise exhaustion
Authors: Gutmann Ludwig , Weidman David , Gutierrez Alvaro 
Published: January 2005

AbstractA 66‐year‐old man with Lambert–Eaton myasthenic syndrome, polyneuropathy, and small cell lung cancer, developed profound muscle weakness with a prolonged period of ventilatory dependency. Electrophysiological studies demonstrated very small compound muscle action potentials in response to supramaximal nerve stimulation, limited tetanic and postexercise facilitation, and prolonged prominent postexercise exhaustion (40–60% of baseline value) persisting up to 20 minutes. It is hypothesized that these changes may reflect both a severe defect in acetylcholine release and decreased availability of releasible acetylcholine from the terminal axon.
Quantitative EMG analysis and longitudinal nerve conduction studies in a Refsum's disease patient
Authors: Kuntzer Thierry , Ochsner François , Schmid Florence , Regli Franco 
Published: January 2005

AbstractA patient with anosmia and night blindness had repeated clinical and electrophysiological examinations during a 21‐year period. Within the first 11 years, he experienced two subacute episodes of numbness with weakness and ataxia. Over the 10 ensuing years, no additional functional disability appeared. We looked retrospectively for a correlation between repeated manual muscle scoring and different nerve conduction parameters. Further studies were done in order to estimate reinnervation in proximal and distal muscles and to assess autonomic functions. A direct relationship was found between the magnitude of muscle weakness and the amplitude of compound muscle action potentials, whereas nerve conduction velocities were inhomogeneously reduced but almost unchanged over time. Parasympathetic tests were normal but sympathetic skin responses were absent. As estimated by macro‐EMG and turns‐amplitude analysis the compensatory reinnervation was very high. We conclude that, in Refsum's disease, recurrent segmental demyelination of a significant portion of the motor units can occur in parallel with exacerbations of weakness, and that a considerable degree of progressive motor and sudoromotor axonal loss can be found although there is an apparent long‐term clinical stabilization of the neuropathy. © 1993 John Wiley & Sons, Inc.
Increased spike‐frequency adaptation and tea sensitivity in dorsal root fibers after sciatic nerve injury
Authors: Utzschneider David A. , Bhisitkhul Robert B. , Kocsis Jeffery D. 
Published: January 2005

AbstractExcitability of rat dorsal root axons were studied 3 weeks after injuryto the sciatic nerve. Whole nerve recordings were obtained from injured andcontrol nerves in a sucrose gap chamber. Constant current depolarization pulses (30–200 ms) applied approximately 50% above the stimulus strength required for maximal amplitude compound action potentials (CAPs) evoked burst of action potentials in the dorsal root which displayed spike adaptation. The depolarization‐induced burst response of the dorsal roots was greatly reduced after crush or transection of the sciatic nerve. However, application of the potassium channel blocker, tetraethylammonium (TEA), restored the burst discharge in injured dorsal root axons. Brief tetanic stimulation of the dorsal root also induced an afterhyperpolarization (AHP) that was twice as large in the transection group as compared to the control group, and which was blocked by TEA. There were no changes seen in the amplitude of the compound action potential, frequency‐following characteristics, refractory properties, or 4‐AP sensitivity in the dorsal roots after peripheral nerve injury. These results suggest that there is enhanced spike adaptation that occurs at the same time as an increase in the sensitivity to the potassium channel blocker, TEA, in axon regions proximal to the site of nerve injury and have implications for the pathophysiology of nerve injury. © 1993 John Wiley & Sons, Inc.
Muscle pain: Animal and human experimental and clinical studies
Authors: Marchettini Paolo 
Published: January 2005

AbstractThe search for the identification of the sensory apparatus encoding muscle pain sensation in humans is recounted. Basic neurophysiologic animal studies, leading to a description of slowly conducting afferent from muscle and definition of high threshold polymodal muscle nociceptors, and pioneer psychophysic human studies together with recent microneurographic experiments in humans are described. The phenomena of muscle pain broad localization and distant referral are discussed, and clinical implications are extrapolated to interpret muscle pain as a localizing sign of mononeuropathy or radiculopathy. The identification of human muscle nociceptors has defined the scientific standard to test emerging clinical descriptions having muscle pain as a symptom. © 1993 John Wiley & Sons, Inc.
Causalgia—reflex sympathetic dystrophy—sympathetically maintained pain: Myth and reality
Authors: Dotson Rose M. 
Published: January 2005

AbstractCausalgia, reflex sympathetic dystrophy, and sympathetically maintained pain (SMP) are a complex group of disorders, with symptoms of spontaneous/stimulus‐induced pain and vasomotor, sudomotor or skeletomotor dysfunction of the involved area. Sympatholysis has been recommended for diagnosis/classification and treatment of these patients. Lack of adequate placebo control makes the physiologic response to this intervention unclear. Sensitization of wide dynamic range (WDR) neurons in the central nociceptive pathway has been proposed as a key element in pathophysiologic mechanisms of these disorders. Low threshold mechanoreceptors and nociceptors have been implicated as the primary afferents transmitting signals to or maintaining sensitization of WDR neurons in SMP. Vasomotor disturbances may result from antidromic vasodilatation, vasoparafytic dilatation, normal somatosympathetic reflexes, and denervation supersensitivity. There is conflicting information regarding the use of phentolamine and clonidine in these pain syndromes. Treatment of these patients remains a challenge given the many potential underlying mechanisms. © 1993 John Wiley & Sons, Inc.
CMAP dispersion, amplitude decay, and area decay in a normal population
Authors: Taylor Peter Kenneth 
Published: January 2005

AbstractThe aim of this investigation was to define the boundaries of compound motor action potential (CMAP) dispersion, amplitude decay, and area decay in a control population and determine their dependence on external variables such as age and interelectrode distance. Measurements were made from median, ulnar, and common peroneal motor nerves of 110 normal subjects of ages 15–90 years. Significant differences between nerves were found in mean values of each parameter. Dispersion and amplitude decay increased with the square of age in all three nerves, while area decay increased with age in the median nerve. Dispersion was the main cause of amplitude decay. Use of regression equations to predict dispersion and amplitude decay in each nerve significantly tightened confidence limits and should therefore increase the accuracy of these parameters in detecting demyelinating pathology in peripheral nerve. © 1993 John Wiley & Sons, Inc.
β‐Adrenergic potentiation of E–C coupling increases force in rat skeletal muscle
Authors: Cairns Simeon P. , Dulhunty Angela F. 
Published: January 2005

AbstractWe examined the mechanism(s) which allow terbutaline, a β2‐adrenergic agonist, to increase isometric force in bundles of normal and denervated rat soleus fibers. Terbutaline (10 μmol/L) potentiated tetanic contractions during exposure to 1 mmol/L ouabain, 10 μmol/L nifedipine, or 0.5 mmol/L iodoacetate. Terbutafine induced equivalent increases in submaximal potassium (K+) contracture and tetanic force: these effects were mimicked by 2 mmol/L dibutyrl‐cyclic AMP. Therefore, terbutaline increased force by a cyclic AMP‐dependent mechanism other than enhancement of sodium‐pump activity, dihydropyridine sensitive Ca2+ currents, glycolysis, or action potentials. Pretreatment with 1 mmol/L caffeine induced submaximal potentiation of peak tetanic force but prevented further potentiation by terbutaline. This suggested that terbutaline did not influence the myofilaments, but acted on the sarcoplasmic reticulum (SR) to increase the myoplasmic Ca2+ concentration and hence force production. We speculate that force is potentiated following β‐adrenoceptor activation by a cyclic AMP‐dependent phosphorylation of Ca2+ release channels to facilitate SR calcium release during tetanic stimulation. © 1993 John Wiley & Sons, Inc.
Hereditary motor and sensory neuropathy type I: Clinical and neurographical features of the 17p duplication subtype
Authors: Hoogendijk Jessica E. , de Visser Marianne , Bolhuis Pieter A. , Hart Augustinus A. M. , de Visser Bram W. Ongerboer 
Published: January 2005

AbstractForty‐four affected individuals, aged 8–68 years (mean 34 years), from six families with hereditary motor and sensory neuropathy type I (HMSN) I, Charcot–Marie–Tooth disease type (1) were investigated to determine the clinical and electroneurographical characteristics of the HMSN I subtype that is defined by the presence of a DNA duplication on chromosome 17p. Motor nerve conduction velocity (MNCV) and, to a lesser extent, compound muscle action potential amplitude, were inversely related to clinical severity. Neither clinical severity nor MNCV were significantly related to age. These results suggest that the primary pathological process is not, or only slightly active after childhood. © 1994 John Wiley & Sons, Inc.
Congenital myopathies
Authors: Bodensteiner John B. 
Published: January 2005

AbstractSeveral dozen congenital myopathies are defined by clinical and morphological criteria. The application of the current generation of scientific techniques including immunohistochemistry and molecular genetics has resulted in the expansion of our knowledge and understanding of the well‐established conditions including central core myopathy and centronuclear/myotubular myopathy and allowed greater understanding of the interrelationships of some of the less common or less wellestablished conditions. In the near future molecular genetics may allow the identification of the specific gene defect in many of these diseases. This article reviews the major congenital myopathies and presents some of the information gained by application of new technology to these conditions. © 1994 John Wiley & Sons, Inc.
The familial occurrence of carpal tunnel syndrome
Authors: Radecki Patrick 
Published: January 2005

AbstractEpidemiological studies of the carpal tunnel syndrome have generally overlooked the possibility of a familial occurrence. A prospective study was undertaken to determine the prevalence and significance of a positive family history of carpal tunnel syndrome. Seventy‐ive of 253 women and 40 of 168 men with a confirmed carpal tunnel syndrome had at least one relative with symptoms of, or surgery for, carpal tunnel syndrome. A positive family history was predictive of a median abnormality or prior surgery at the carpal tunnel (chi‐square = 20.484, P < 0.001). The 84 patients with a prior carpal tunnel surgery, likely the most well informed historically, had a positive family history of 39.3% versus 13.3% in the 279 patients without median latency slowing. The familial occurrence appears crucial in the epidemiological study of carpal tunnel syndrome, and may be important in the selection of normal subjects for electrodiagnostic standards. © 1994 John Wiley & Sons, Inc.