bluuebunny/crossref_metadata_2025_split huggingface dataset:
The quadriceps femoris muscle in 20–70‐year‐old subjects: Relationship between knee extension torque, electrophysiological parameters, and muscle fiber characteristics
Authors: Stålberg E. , Borges O. , Ericsson M. , Essén‐Gustavsson B. , Fawcett P. R. W. , Nordesjö L. O. , Nordgren B. , Uhlin R. 
Published: January 2005

AbstractComparisons have been made between torque (isometric and isokinetic), electrophysiological (SFEMG, Macro EMG), and muscle fiber characteristics in the vastus laterlis muscle of both legs in healthy subjects aged between 20 and 70 years. Torque was greater in males and decreased with age in both sexes. Multifactorial analysis showed a positive correlation between torque, body surface area, and mean fiber area. These variables explained only about 30–40% of the torque changes. The electrophysiological parameters (Marco EMG amplitudes and fiber density) revealed evidence of reinnervation, indicating preceeding denervation and therefore loss of motor units. It was concluded that this fall out of motor units also contributes to the reduction in torque, when compensatory reinnervation begins to fall. Other factors, such as reduction in muscle fiber contractility, metabolic factors, and central factors, may also play a role in age‐related reduction in torque.
Acquired inflammatory demyelinating polyneuropathies: Clinical and electrodiagnostic features
Authors: Albers James W. , Kelly John J. 
Published: January 2005

AbstractThe acquired demyelinating polyneuropathies include acute (AIDP, Guillain‐Barré syndrome, GBS) and chronic (CIDP, dysproteinemic) forms which differ primarily in their temporal profile. They are inflammatory‐demyelinating diseases of the peripheral nervous system and likely have an immunologic pathogenesis. Although these neuropathies usually have a characteristic presentation, the electromyographer plays a central role in their recognition, since the demyelinating component of the neuropathy, which greatly reduces the differential diagnosis, is often first identified in the electromyography laboratory. In AIDP, the electromyographer, in addition to establishing the diagnosis, can sometimes predict the prognosis. Recognition of the chronic and dysproteinemic forms of acquired demyelinating polyneuropathy is important since they are treatable. The dysproteinemic forms also may be associated with occult systemic disorders that also may require treatment, independent of the neuropathy.
Diverse electrophysiological spectrum of the Lambert–Eaton myasthenic syndrome
Authors: Oh Shin J. 
Published: January 2005

AbstractAmong 13 patients with the Lambert–Eaton myathenic syndrome (LEMS), three different patterns on the repetitive nerve stimulation test were observed at the time of initial testing. Type 1 pattern, seen in one patient, had low normal CMAP amplitude, decremental response at the low rate of stimulation (LRS), and relatively normal response at the high rate of stimulation (HRS). Type 2, seen in nine patients, had the classical triad: low CMAP amplitude, decremental response at LRS, and incremental response at HRS. Type 3, seen in three patients, showed low CMAP amplitude, decremental response at LRS, and initial decremental response at HRS. We believe that these three patterns represent different degrees of blocking in LEMS, from the mildest in type 1 to the most severe in type 3. Since types 1 and 3 can be misinterpreted as myasthenia gravis patterns, they must be recognized in LEMS and an incremental response documented by prolonged stimulation at HRS.
Electrodiagnostic evolution of carcinomatous sensory neuronopathy
Authors: Donofrio Peter D. , Alessi Anthony G. , Albers James W. , Knapp Robert H. , Blaivas Mila 
Published: January 2005

AbstractSensory neuronopathy is a well‐recognized remote effect of carcinoma. We report the clinical and electrodiagnostic evolution of a sensory neuronopathy in a patient with carcinoma of the lung. Serial electrophysiologic studies suggest transformation from normal peripheral nerve function through early posterior root involvement to absent sensory nerve function. Diffuse motor conduction abnormalities occurred late in the disease, perhaps reflecting motor axon changes associated with disuse.
The blood–nerve barrier in Wallerian degeneration: A sequential long‐term study
Authors: Seitz Rüdiger J. , Reiners Karlheinz , Himmelmann Frank , Heininger Kurt , Hartung Hans‐Peter , Toyka Klaus V. 
Published: January 2005

AbstractThe blood–nerve barrier (BNB) for serum proteins was studied after a crush lesion of the murine sciatic nerve or after transsection with persistent Wallerian degeneration. Using single intraperitoneal injections of biotinylated human albumin, transferrin, IgG, and complement components as tracers, the integrity of the BNB during degeneration and regeneration was determined over time. In Wallerian degeneration induced by crush the BNB became increasingly leaky, with a maximum in the distal stump 8 days after crush (i.e., during early regeneration). When regeneration potentials could first be elicited from the small foot muscles and when thinly myelinated nerve fibers were present, the BNB gradually regained its barrier function and was nearly intact on day 30 after crush. After transsection breakdown of the BNB persisted beyond 30 days. The BNB leakage may foster repair by allowing exchange of trophic factors of large molecular size during nerve regeneration.
Muscle fatigue, effects of training and disuse
Authors: Hainaut Karl , Duchateau Jacques 
Published: January 2005

AbstractThe study of muscle fatigue started about a century ago, when it was proposed that the observed decrease in force during prolonged voluntary contractions resulted from changes in central processes which reduced the motor drive. In the middle of this century it was noticed that this loss of force could not be restored by maximal electrical stimulation of the motor nerve, and thus the importance of peripheral mechanisms, located beyond the motoneuron, was emphasized. However, it was not clear which peripheral site was most important in decreasing the muscle mechanical capacity during fatigue. More recently, the comparison between peripheral failures during sustained and intermittent contractions indicated that recorded mechanical changes underwent deterioration which was not closely related to the recorded electrical changes. It was thus proposed that muscle intracellular processes dominate the force decrease during muscle fatigue. This concept has been substantiated by the study of standard fatigue tests performed in control, trained, and disused human muscles, as reviewed in this paper.
Ephaptic transmission in hemifacial SPASM: A single‐fiber EMG study
Authors: Sanders Donald B. 
Published: January 2005

AbstractIn two patients with hemifacial spasm (HFS), single‐fiber EMG recordings in facial muscles demonstrated low jitter in the late responses produced by stimulation of peripheral branches to other facial muscles. Surgical decompression of the facial nerve in one patient was followed by clinical improvement and disappearance of the abnormal late responses. These observations are consistent with the hypothesis that there is ephaptic transmission among peripheral branches of the facial nerve at the site of compression in HFS.
AAEE case report #19: Ischemic monomelic neuropathy
Authors: Levin Kerry H. 
Published: January 2005

AbstractA case study of a 50‐year‐old man who awakened from aortobifemoral bypass graft surgery with painful burning and numbness of the left foot is reported. Angiography showed embolic occlusion of the left popliteal artery proximal to the knee. Nerve conduction studies performed 1 year after occlusion showed loss or severe reduction of distal left sensory and motor amplitudes, and needle electrode examination showed fibrillation potentials in foot and distal leg muscles. The findings were felt to represent the result of acute ischemic nerve damage in the left leg. The clinical and electromyographic features of this entity will be described and comparisons will be drawn to experimental ischemic neuropathy and diabetic neuropathy.
Position of the elbow in determination of abnormal motor conduction of the ulnar nerve across the elbow
Authors: Bielawski Martin , Hallett Mark 
Published: January 2005

AbstractRoutine evaluation of patients for suspected ulnar neuropathy includes testing of motor conduction velocity across the elbow, although the best position of the elbow for this test is controversial. The preferred testing position—elbow flexion or extension—was studied by determining the yield of abnormality at both positions in patients selected for possible ulnar nerve abnormalities unrelated to motor conduction. We found no major differences between the flexed or extended position of the elbow except that normal values for each of these positions varied. The yield of abnormal findings was greatest from measuring absolute motor conduction velocity across the elbow as opposed to comparing the difference in velocities between the elbow and either adjacent segment.
Recurrent myoglobinuria and HIV seropositivity: Incidental or pathogenic association?
Authors: Younger David S. , Hays Arthur P. , Uncini Antonio , Lange Dale J. , Lovelace Robert E. , DiMauro Salvatore 
Published: January 2005

AbstractThere have been few cases of polymyositis in patients with AIDS, and polymyositis is rarely a cause of myoglobinuria. We studied a 20‐year‐old homosexual man with recurrent myoglobinuria. He was asymptomatic between episodes. Each episode was accompanied by muscle pain, limb weakness, high serum levels of creatine kinase, and pigmenturia. Muscle biopsy showed active necrosis without inflammation or abnormalities of glycolytic or other energy‐generating enzymes. Antibodies to HIV were present in serum. Clinical evidence of AIDS has not developed in 2 years. Recurrent myoglobinuria may be another consequence of HIV infection.
Reversible axonal neuropathy from the treatment of AIDS and related disorders with 2′,3′‐dideoxycytidine (ddc)
Authors: Dubinsky Richard M. , Yarchoan Robert , Dalakas Marinos , Broder Samuel 
Published: January 2005

AbstractA total of 20 patients with acquired immune deficiency syndrome (AIDS) or AIDS‐related complex (ARC) received the anti‐retroviral drug 2′,3′,dideoxycytidine in a phsae I study at doses ranging from 0.03 mg/kg every 8 hours to 0.25 mg/kg every 8 hours. Of the 11 patients who participated in the study for more than 5 weeks, 9 developed symptoms and signs of a mainly sensory painful neuropathy that was confirmed by electromyography to be mixed sensory and motor neuropathy of axonal type. The neuropathy which developed on dideoxycytidine occurred between 9 and 12 weeks of treatment. One patient, who had the drug stopped at 3 weeks owing to thrombocytopenia, developed a similar clinical picture of a sensory peripheral neuropathy after 2 weeks off dideoxycytidine. However, he did not have electromyographic evidence of a neuropathy, and he subsequently returned to normal clinically while taking a lower dose of dideoxycytidine in an alternating regimen. Five patients were withdrawn from the study because of the neuropathy. The pattern of this neuropathy was different from that of the slowly progressive painful neuropathy of AIDS, in that there was (1) a sudden onset of intense burning discomfort in both feet sparing the hands at about the tenth week (mean 10.4 weeks) of treatment, (2) there was motor involvement in some patients without progression, and (3) onset of the neuropathy was temporally related to the administration of dideoxycytidine and began to resolve 3–5 weeks after its discontinuation. We believe that dideoxycytidine can be an axonal toxin, especially when given in high dose continuous regimens. We are now exploring whether a low‐dose regimen or regimens that incorporate a drug rest period can obviate this toxicity.
AAEE case report #20: Hereditary motor and sensory neuropathy, type I
Authors: Chad David A. 
Published: January 2005

AbstractA case study is reported regarding a 32‐year‐old man with classic clinical and electrophysiologic features of hereditary motor and sensory neuropathy, type I (HMSN I), a slowly progressive autosomal dominant condition marked by slow motor and sensory velocities and generalized segmental demyelination. Another clinically similar autosomal dominant neuropathy (HMSN II) is distinguished from HMSN I by nearly normal nerve conduction velocity. Acquired demyelinating neuropathy may occasionally resemble HMSN I clinically, but the former demonstrates electrophysiologic features not seen in the latter such as conduction block, dispersed compound muscle action potentials, and differential slowing of conduction velocity. Neuropathologic studies of HMSN I suggest that both neuronal and Schwann cell distrubances play a role in pathogenesis.
Median to radial latency difference test in mild carpal tunnel syndrome
Authors: Pease William S. , Cannell Christopher D. , Johnson Ernest W. 
Published: January 2005

AbstractElectrodiagnostic assessment of carpal tunnel syndrome (CTS) is hampered by the normal variability of conduction velocity, amplitude and duration of evoked responses, and hand temperature. Comparative testing of other nerves in the same hand may control for these variables and improve sensitivity for detection of mild focal entrapment. In consecutive cases referred for evaluation, antidromic sensory latencies were recorded from the thumb over 10 cm segments of the median and radial nerves, and the difference between these latencies was calculated. Median sensory antidromic conduction to digit III, ulnar sensory conduction, and median motor latency measurements were also made. Three hundred and thirty‐three upper limbs were studied in 262 patients. All tests were normal in 73 arms. Mild conduction slowing was identified in 86 median nerves. The median–radial latency difference was increased in 87% of these mild cases. The median–ulnar latency difference was diagnostic in 88%. Either median–radial or median–ulnar latency differences were abnormal in all confirmed cases. The routine median motor and sensory distal latency tests had sensitivities of 29% and 52%, respectively. Radial responses were elicited in 99% of the hands studied. The median–radial latency difference in digit I is a sensitive indicator of mild CTS that can be measured quickly with a minimum of discomfort.
Ultrastructural localization of calcium binding sites on human muscle cell surface
Authors: Moggio M. , Jann S. , Adobbati L. , Prelle A. , Gallanti A. , Fagiolari G. , Pellegrini G. , Scarlato G. 
Published: January 2005

AbstractCalcium (Ca2+) is mainly bound to anionic phospholipids and to sialic acid at the cell surface. We studied the ultrastructural localization of these Ca2+ binding sites in normal human muscle fibers, using Polymyxin B as a marker for anionic phospholipids and the lectin Limulus Polyphemus as a probe for sialic acid. We found that anionic phospholipids have a patchy distribution along the muscle sarcolemma, with a preferential localization at the I band level and at the junction between the I and A band. Sialic acid has an uniform distribution along the muscle plasma membrane and basal lamina. Our observations suggest that the plasma membrane, basal lamina, and transverse tubular system play an important role in providing the negative charge of the human muscle cell surface and that these structures may be involved in the binding of calcium.
Automatic analysis of heart rate variation: II. Findings in patients attending an EMG laboratory
Authors: Nogués Martin A. , Stålberg Erik V. 
Published: January 2005

AbstractAn automatic method was used to measure the heart rate variation with breathing in patients with different neuromuscular conditions attending a laboratory of electromyography (EMG). The objective was to determine the frequency of abnormalities in various conditions and the relationship between R‐R variation and different nerve conduction parameters. The percentages of reduced R‐R variation were 73% in diabetics, 35% in Guillain–Barré syndrome, 22% in amyotrophic lateral sclerosis, and 50% in amyloidosis. R‐R variation in diabetics was significantly correlated to most parameters of nerve conduction. In Guillain–Barré syndrome it correlated significantly with the ulnar and median M‐response amplitudes. Most patients with myopathies showed normal R‐R variation.
Are there motor fibers in the sural nerve?
Authors: Liguori Rocco , Trojabodrg Werner 
Published: January 2005

AbstractA case of anomalous innervation of the abductor digiti quinti of the foot (ADQ)via the sural nerve is described. A muscle action potential from the ADQ could be elicited by stimulation of both the sural and the posterior tibial nerves.
Quantitative EMG in inflammatory myopathy
Authors: Barkhaus Paul E. , Nandedkar Sanjeev D. , Sanders Donald B. 
Published: January 2005

AbstractFifty‐four quantitative electromyographic (EMG) studies were made in 37 patients with inflammatory myopathy (IM) at different points in their clinical course and tretment. All studies were performed in the biceps brachii which varied in clinical strength. Motor unit action potentials (MUAPs) in 45 studies and EMG interference pattern (IP) in 48 studies were recorded using a concentric needle electrode. Macroelectromyographic (Macro‐EMG) MUAPs were recorded from 10 patients in 14 studies. MUAP analysis revealed a myopathic pattern (decreased duration and/or area: amplitude ratio) in 69% of studies. IP analysis was more sensitive than MUAP analysis, demonstrating a myopathic pattern in 83% of studies. Macro‐EMG MUAP amplitudes were reduced in two studies, minimally increased in one study and normal in the remainder; in 6 (40%) studies, fiber density was slightly increased. Thus, reinnervation does not seem to play an important role in motor unit remodeling in IM.
Nerve regeneration and reinnervation after limb amputation and replantation: Clinical and physiological findings
Authors: Krarup Christian , Upton Joseph , Creager Mark A. 
Published: January 2005

AbstractA 22‐year‐old male was studied 3½–&4½ years after a traumatic section‐avulsion amputation of the left upper extremity at the level of the distal humerus. The arm was reattached after a cold ischemia time of 4–5 hours and good vascularization was obtained. The ulnar nerve was repaired early with an end‐to‐end juncture while the median and radial nerves were repaired after seven months delay using a combination of vascularized radial nerve and nonvascularized sural nerve grafts. Some intrinsic hand muscle function had recovered. Pin‐prick and touch sensation was present in all digits, although localization of touch stimulation was poor. Evoked motor responses had recovered by 25–50% of control amplitude in ulnar‐innervated and by 10–25% in median‐innervated muscles. Amplitudes of sensory responses from digit V had recovered by 25% and from digits I and III by 1–5%. Fast‐adapting touch receptors had become reinnervated. There was electrophysiological evidence of aberrant sensory regeneration and of abnormal connections between sensory and motor fibers. Digital blood flow measurements suggested the presence of vascular obstruction in vessels of the replanted upper extremity. However, the digital vasconstriction during cold exposure indicated regeneration of sympathetic nerve fibers.
Invited review: Limitations in predicting pathologic abnormality of nerves from the EMG examination
Authors: Dyck Peter James 
Published: January 2005

AbstractAlthough electromyography (EMG = nerve conduction and needle electromyographic examination) is among the most sensitive and reliable approaches to detect and even to characterize certain aspects of nerve disease, it is important for physicians to appreciate that EMG has limited value in (1) inferring symptoms and neuropathic deficit (particularly the overall deficit recorded by clinical neurologists), (2) inferring involvement of small‐diameter fibers, (3) inferring underlying biochemical or other pathophysiologic derangement, (4) inferring the presence and type and pathologic alterations in single fibers or Schwann cells, or (5) inferring interstitial pathologic abnormality. For 1 and 2, an adequate neurologic history and examination in needed. For 2, quantitative sensory (QSE) and quantitative autonomic (QAE) examination and histologic study of nerve often are especially helpful. For 3, clinical evaluation and a variety of laboratory examinations are needed. For 4 and 5, clinical evaluation and/or pathologic study of nerve may be neededElectromyography has deservedly gained considerable acceptance as a worthwhile evaluative procedure for the study of neuromuscular disease. For some purposes, however it is of limited value and other evaluative procedures are more informative. In this review, I trace the history of some of the reasons for the popularity of EMG and highlight some of its limitations. The purpose is not to diminish EMG or to elevate the procedure of nerve biopsy, rather to provide a conceptual framework for how these techniques and the clinical and other laboratory examinations can be used together in the assessment and follow‐up of neuropathy.
Clinical use of the magnetic stimulator in the investigation of peripheral conduction time
Authors: Britton Thomas C. , Meyer Bernd‐Ulrich , Herdmann Jörg , Benecke Reiner 
Published: January 2005

AbstractThe application of rapidly changing magnetic fields (magnetic stimulation) over the neck or lower back elicits EMG responses in the muscles of the arm or leg respectively. Such responses have stable onset latencies but their amplitudes vary depending on the position of the coil over the neck or lower back. Supramaximal responses could not be obtained. Comparison of onset latencies with estimates of peripheral conduction time using a conventional F‐wave technique suggest that the site of excitation of the motor axons is about 1.3 msec conduction time distal to the cervical motoneurons and 3 msec distal to the lumbosacral motoneurons. Response configuration after paravertebral magnetic stimulation was similar to that of the standard electrically evoked M‐wave in the small hand muscles but not in lower limb muscles. Responses in lower limb muscles after paravertebral magnetic stimulation may consist of additional F‐wave and H‐reflex components. The possible clinical role of paravertebral magnetic stimulation in the investigation of peripheral and central motor pathways is discussed in the light of these findings.
Enhancement of K+ conductance improves in vitro the contraction force of skeletal muscle in hypokalemic periodic paralysis
Authors: Grafe Peter , Quasthoff Stefan , Strupp Michael , Lehmann‐Horn Frank 
Published: January 2005

AbstractAn abnormal ratio between Na+ and K+ conductances seems to be the cause for the depolarization and paralysis of skeletal muscle in primary hypokalemic periodic paralysis. Recently we have shown that the „k+ channel opener”︁ cromakalim hyperpolarizes mammalian skeletal muscle fibers. Now we have studied the effects of this drug on the twitch force of muscle biopsies from normal and diseased human skeletal muscle. Cromakalim had little effect on the twitch force of normal muscle whereas it strongly improved the contraction force of fibers from patients suffering from hypokalemic periodic paralysis. Recordings of intracellular K+ and Cl− activities in human muscle and isolated rat soleus muscle support the view that cromakalim enhances the membrane K+ conductance (gK+). These data indicate that ”︁K+ channel openers„ may have a beneficial effect in primary hypokalemic periodic paralysis.