bluuebunny/crossref_metadata_2025_split huggingface dataset:
Far‐field potentials
Authors: Dumitru Daniel , Jewett Don L. 
Published: January 2005

AbstractFar‐field potentials are produced by neural generators located at a distance from the recording electrodes. These potentials were initially characterized incorrectly as being of positive polarity, widespread distribution, and constant latency; however, recent advances have clearly demonstrated that far‐field potentials may be either positive or negative depending upon the location of the electrodes with respect to the orientation of the dipole generator. Additionally, peak latencies in the far‐field can vary with alterations in body position and the spatial distribution of far‐field potentials, while widespread, is not uniform. Recent studies of far‐field potentials suggest how such waveforms are produced when the symmetry of an action potential, as recorded by distant electrodes, is broken by such factors as differing conductivities of volume conductor compartments, direction of action potential propagation, size differentials in adjoining body segments, or the termination of action potential propagation in excitable tissue. Human, animal, and computer experiments support the preceding generalizations. These new explanations are directly applicable to such far‐field potentials as the short latency somatosensory‐evoked potential. Furthermore, since far‐field potentials can also occur in muscle tissue, one should expect that these generalizations will hold with respect to electromyographic potentials. © 1993 John Wiley & Sons, Inc.
Thermal sensitivity in demyelinating neuropathy
Authors: Chaudhry Vinay , Crawford Thomas O. , Derossett Sarah E. 
Published: January 2005

AbstractAn 8‐year‐old girl with demyelinating peripheral neuropathy was observed to get markedly weak coincident with a febrile illness. With return of body temperature to normal over 24 hours, her strength improved back to baseline. Subsequently, we studied the effect of temperature on CMAP amplitude of two motor nerves in the patient and two control subjects. Both temperature, measured orally, was raised by immersing the subjects in hot water and lowered by passive cooling. With increase in temperature to 39.5°C, the CMAP amplitudes were reduced by 80% in the patienťs nerves compared to only 48% in the control nerves. These changes recovered with cooling to 36.9°C. We conclude that demyelinated peripheral nerves are more susceptible to temperature‐induced impulse blocking than healthy nerves and provide the first published evidence of the clinical consequences of this phenomenon in a demyelinating disease other than multiple sclerosis. © 1993 John Wiley & Sons, Inc.
Sural nerve water in vivo in normal humans measured by magnetic resonance spectroscopy: Relation to age, height, gender, and neurological profile
Authors: Eaton R. Philip , Sibbitt Wilmer L. , Bicknell Joseph M. , King Molly K. , Griffey Richard H. , Sibbitt Randy R. 
Published: January 2005

AbstractTo enable the quantitative assessment of peripheral nerve structure and function, we determined the normal values for sural nerve hydration structure as measured by magnetic resonance proton imaging, and for neurological function with scores for neuropathic symptoms, signs, and nerve conduction properties. Normal human sural nerves contain 24.8 ± 3.4% water. The structural water content of the nerves did not vary systematically in relation to age, height, gender, sural nerve conduction, neurologic symptoms, or examination deficits. In contrast, the neurological function scores were significantly influenced by age and selectively by height. Both nerve structure and function were stable over a 1‐year interval. Measurement of human sural nerve water content in vivo by magnetic resonance proton imaging, and quantitation of the neurological profile of symptoms, signs, and conduction velocity are useful, noninvasive tools for the investigation of diseases in which changes in nerve structure may be related to alterations in nerve function. © 1993 John Wiley & Sons, Inc.
Long‐lasting supernormal conduction velocity after sustained maximal isometric contraction in human muscle
Authors: van der Hoeven J. H. , Van Weerden T. W. , Zwarts M. J. 
Published: January 2005

AbstractLocal muscle fatigue (1 min maximal voluntary contraction) and recovery were studied by means of surface and invasive EMG on elbow flexors to record the changes in muscle fiber conduction velocity (MFCV), median power frequency (MPF), integrated EMG (IEMG), and force. The main finding was a long‐lasting “supernormal” MFCV during recovery, for at least 1 hour. After a normalization phase, the MFCV and MPF continued to increase reaching a steady state at supernormal values after 10–12 min. Mean MFCV increase at 20% MVC after 15‐min recovery was 0.58 m · s‐1 (12%). Postfatigue IEMG values were increased at all contraction levels. In combination with near normal force levels, this resulted in a decrease in “neuromuscular efficiency” (force/IEMG). We suggest that this IEMG increase is mainly a result of the MFCV increase. The MFCV changes in fastest and slowest fibers found with the invasive method indicate a relatively equal effect on type I and II fiber types. A possible explanation of the supernormal MFCV is muscle fiber swelling, in combination with altered membrane properties. © 1993 John Wiley & Sons, Inc.
The influence of the reference electrode on CMAP configuration
Authors: Kincaid John C. , Brashear Allison , Markand Omkar N. 
Published: January 2005

AbstractThe ulnar, hypothenar compound muscle action potential often shows a double‐peaked configuration in the negative phase component while the median, thenar potential has a simple dome shape. To investigate the origin of these differences we evaluated the activity at the belly and tendon electrode locations by referencing those sites to an electrode on the contralateral hand. The tendon sites are not electrically inactive. The ulnar tendon electrode contributes a large amplitude potential which corresponds to the second peak of the ulnar belly‐tendon potential. The median tendon electrode contributes only a minimal component to the negative phase of the belly‐tendon potential. The distribution of such potentials throughout the hand is evaluated and possible mechanisms for the presence of a tendon potential as well as the differences between ulnar and median sites are discussed. © 1993 John Wiley & Sons, Inc.
Retardation of fast axonal transport in wobbler mice
Authors: Mitsumoto Hiroshi , Kurahashi Kozo , Jacob Jane M. , McQuarrie Irvine G. 
Published: January 2005

AbstractTo investigate axonal function in a model of early motor neuron disease, we examined fast and slow components of anterograde axonal transport in the less‐affected hindlimb motor neurons of wobbler mice. To study the fast component (FC), we injected tritiated amino acids into the lumbar spinal cord and retrieved the sciatic nerve after 2 or 3 h. The transport distance was the extent of the plateau of labeling; regression analysis indicated that FC was 25% slower in wobbler mice than in unaffected littermates (P < 0.01). To study slow component (SC), [35S] methionine was injected. Transport distances were to the peaks of labeling for structural proteins after 2 or 3 weeks. Rates for each subcomponent (SCa and SCb) were unaffected by wobbler disease. Because the rate of retrograde FC is also unaffected (Mitsumoto et al., Muscle & Nerve 13:121–126, 1990), we conclude that wobbler disease specifically retards anterograde FC in less‐affected hindlimb motor neurons, whereas all components of axonal transport are retarded in forelimb motor neurons. © 1993 John Wiley & Soncs, Inc.
Neuromuscular response in man to repetitive nerve stimulation
Authors: Morita Hitoshi , Shindo Masaomi , Yanagawa Sohei , Yanagisawaw Nobuo 
Published: January 2005

AbstractPaired stimulation has been used extensively in clinical neuropathysiology. We studies change in the sizes of compound muscle action potencial (CNAPs) in humans after a single electrical stimulus to the peripheral nerve. When the interstimulus intervals were varied, the second potentials underwent refractoriness and then were facilitated up to 20–30 ms, thereafter being depressed for 160–200 ms. When intensities were graded at fixed intervals for motor fibers the maximal effects was obtained with liminal stimulation, but was no longer observed at supramaximal stimulation. When the intrensity used to obtain M‐resposes was half the maximum, maximal facilitations were 35% (CNAP) and 17% (CMAP) of the first potential, the respective maximal depressions being 13% and 42%. When the sizes of the two CNARs were equalized by adjusting the second stimuli, the CMAP was facilitated (26%) up to 65 ms, thereafter being depressed (13%). These results must be taken into account when making clinical examinations that use paired stimulation. © 1993 John Wiley & Sons, Inc.
Comparison of directly stimulated with axon‐reflex–mediated sudomotor responses in human subjects and in patients with diabetes
Authors: Kihara Mikihiro , Opfer‐Gehrking Tonette L. , Low Phillip A. 
Published: January 2005

AbstractThe muscarinic receptors of human eccrine sweat gland may be directly stimulated by iontophoresis of acetylcholine (direct response; DIR) and indirectly via nicotinic receptors and an axon “reflex” (AXR). Using a specially designed multicompartmental sweat cell and dual sudorometers, we were able to simultaneously record the evoked DIR and AXR responses. On a second day, we repeated the experiment under identical ambient and stimulus conditions but instead obtained silastic imprints of DIR and AXR for morphometry. Studies were done on 24 controls (mean SD = 47.6 ± 15.1 years) and 23 diabetic subjects (mean ± SD = 49.6 ± 16.3 years). In control subjects, sudorometric DIR recordings were consistently larger than AXR. There was no difference in sweat droplet density by sex, but the size of droplets was larger in males. In diabetic patients 3 of 23 had absent AXR but preserved DIR, suggesting that failure of AXR preceded DIR in patients with neuropathy. Patients with mild neuropathy had an overrepresentation of large diameter droplets in the silastic imprints of both DIR and AXR, while patients with severe neuropathy had a markedly reduced density and small diameter droplets. © 1993 John Wiley & Sons, Inc.
Assessment of diabetic neuropathy: Definition of normal and discrimination of abnormal nerve function
Authors: Claus Detlef , Mustafa Constanze , Vogel Wilfried , Herz Matthias , Neundörfer Bernhard 
Published: January 2005

AbstractOne hundred one normal subjects and 46 patients were investigated. Various objective and subjective tests for polyneuropathies were compared. Motor and sensory nerve conduction velocities are the most sensitive tests. In normals, age hardly influenced nerve conduction velocities. This is believed to be a result of the strict exclusion criteria. Diagnostic sensitivity is also high with the vibration fork test and with vibratometry at the big toe. Results with the method of limits are as reliable and sensitive as more cumbersome techniques, such as the titration method and the forced choice method. Thermal thresholds and cardiovascular tests are less sensitive. The most correct overall classification is attained with a combination of tests reflecting the function of different nerve fiber classes in the peripheral and autonomic nervous systems.
Issue & Opinions: Receiver operating characterist curve anic analysis in the prediction of carpal tunnel syndrome: A model for reporting Electrophysiological data
Authors: Eisen Andrew , Schulzer Michael , Pant Bhanu , MaCneil Maureen , Stewart Heather , Trueman Sandra , Mak Edwin 
Published: January 2005

AbstractReceiver operating characteristic (ROC) curves were used to predict the risk of carpal tunnel syndrome (CTS). Patients were classified clinically as (1) normal exam and no symptoms (169 hands); (2) having a motor and/or sensory deficit typical of CTS (115 hands); (3) having a history characteristic of CTS (156 hands); and (4) nondiagnostic symptomatology (122 hands). Electrophysiological studies consisted of median and ulnar motor, sensory, and palmar measurements. Group mean values for group 1 differed significantly from groups 2 and 3 (not 4) for all measurements, but values overlapped considerably. Median distal motor latency (DMML) combined with median‐ulnar palmar latency differences (MUPLD) had significantly superior discriminant power than other measurements and correlated highly for all groups (r values = 0.71–0.73). These variables were used to construct ROC curves and prediction tables. The approach used allows one to assign a percentage risk of having a CTS and can be used in outcome studies.
AAEM minimonograph #40: Clinical neurophysiology of the respiratory system
Authors: Bolton Charles F. 
Published: January 2005

AbstractDisorders of nerve and muscle are frequent causes of respiratory insufficiency, but current methods often fail to adequately assess the problem. Phrenic nerve conduction and needle electromyography of the diaphragm are of great assistance in identifying the nature and site of the disorder: the various disturbances of central drive, axonal or demyelinating neuropathies of the phrenic nerves, and certain myopathies. These studies may be performed on adults, children, or infants, and in outpatient, general ward, or critical care settings. It is hoped these techniques will stimulate further developments in the field.
Issues & Opinions: Amyotrophic lateral sclerosis: Lower motor neuron disease spreading to upper motor neurons
Authors: Chou Samuel M. , Norris Forbes H. 
Published: January 2005

AbstractContrary to the recently reemphasized notion that the primary neuron involved in amyotrophic lateral sclerosis (ALS) is the cortical (upper) motor neuron (UMN), we believe that the lower motor neuron (LMN) is primarily involved by the retrograde transport of pathogens from neuromuscular junctions, and the disease process spreads monosynaptically to the UMN. Pathologically and epidemiologically, the LMN hypothesis is more logical than the UMN in light of the recent understanding of neuroaxonal transport systems, particularly in regard to anterograde cytoskeleton transport and the kinetics of the force promoting slow axonal transport. By correlating the early pathologic findings, i.e., the swelling of the initial axons and formation of intracytoplasmic inclusions in the LMN, ALS may be regarded as a disease of axonal transport, especially its slow component (SCa). Therapeutic intervention to facilitate SCa should be attempted in ALS. © 1993 John Wiley & Sons, Inc.
Chronic immune activation in the eosinophiliamyalgia syndrome
Authors: McKinley Kevin L. , Harati Yadollah , Schneider Larry W. 
Published: January 2005

AbstractEosinophilia–myalgia syndrome (EMS) is a multisystem illness of uncertain pathogenesis that occurred in an epidemic related to the ingestion of contaminated L‐tryptophan. To investigate the role of immune dysfunction in EMS we prospectively measured a serologic index of T‐cell activation, the soluble interleukin‐2 receptor (slL‐2R), in 7 patients followed into the late stages of the illness. As a group, EMS patients had significantly elevated slL‐2R levels throughout the study. Five patients suffered chronic symptoms of myalgia, arthralgia, muscle cramps, fatigue, or subjective memory impairment and all had persistently elevated slL‐2R levels. Two patients had near‐resolution of EMS and normal slL‐2R levels. We conclude that chronic symptoms are common in EMS and are associated with persistent T‐cell activation as measured by serum slL‐2R levels. These findings suggestthat immunosuppressive treatment may be beneficial in EMS. © 1993 John Wiley & Sons, Inc.
Microneurography, impulse conduction, and paresthesias
Authors: Burke David 
Published: January 2005

AbstractIt is possible to learn more about peripheral nerve function in human subjects than is obtainable with routine nerve conduction studies, and thereby to study the basis of “positive” symptoms, such as paresthesias. Using microneurography, ectopic impulse activity in cutaneous afferents has been recorded in patients suffering from neurologic disorders and in normal subjects in whom paresthesias were provoked by hyperventilation, prolonged tetanization of cutaneous nerves and ischemia. Using relatively simple modifications of standard nerve conduction techniques, the increases in axonal excitability responsible for this ectopic activity have been documented in human volunteers. Hyperventilation increases axonal excitability butdoes not change supernormality, probably because Na+ channels are activated by the decrease in [Ca2+] on the axonal membrane. Prolonged tetanic stimulation and ischemia probably share similar mechanisms. At least in motor axons, postischemic ectopic activity occurs when the hyperpolarization that results from activation of the Na+/K+ pump lowers the membrane potential below the equilibrium potential for K+. A high extracellular [K+] can then result in an inward current producing depolarization and possibly triggering regenerative processes. © 1993 John Wiley & Sons, Inc.
Magnetic stimulation in hemifacial spasm and post–facial palsy synkinesis
Authors: Öge A. Emre , Yazici Jale , Boyaciyan Ari , Tanyeri Sariye , Çlelik Münevver , Konyalioǧlu Rana , Baslo Aynur 
Published: January 2005

AbstractThe facial nerve was stimulated trascranially with a magnetic stimulator in 14 normal controls, 14 hemifacial spasm patients, and 16 post–facialpalsy synkinesis patients. Magnetic stimulation in normal controls revealed muscle responses which had latencies with a mean value of 4.99 ± 0.49 ms and amplitudes of 2.41 ± 1.08 mV. In the same group, transosseal conduction time was calculated to be 1.20 ± 0.13 ms. In the hemifacial spasm group, the amplitudes of the responses on the affected sides were lower as compared to the unaffected sides (mean values 1.78 vs. 2.41 mV, P = 0.01). Also, the threshold to magnetic stimulation was elevated on the affected sides. These findings are suggestive of the presence of a hypoexcitability to magnetic stimulation in the root entry zone. In the post–facial‐palsy synkinesis patients, magnetic stimulation of the affected sides resulted in responses with long latencies and low amplitudes (mean latency 6.34 ms, mean amplitude 0.90 mV). In the recordings made with magnetic stimulation, the difference of the latencies between the two sides was larger as compared to those obtained by electrical stimulation. The transosseal conduction time was also remarkably prolonged on the affected side. These findings may suggest that magnetic stimulation can be an effective method of showing intracranially located lesions of the facial nerve. © 1993 John Wiley & Sons, Inc.
Orthostatic tremor: Clinical and electrophysiologic characteristics
Authors: McManis Philip G. , Sharbrough Frank W. 
Published: January 2005

AbstractOrthostatic tremor, sometimes known as „shaky legs syndrome,”︁ is a disorder of middle‐aged or elderly people characterized by feelings of unsteadiness in the legs and a fear of falling when standing. Patients stand on a wide base but walk normally. These symptoms are due to high‐frequency (13–18 Hz) burst firing in weight‐bearing muscles. They are attenuated by walking and are abolished immediately by sitting. Some authors believe that the disorder is a variant of essential tremor. This study reports the clinical and electrophysiologic features of orthostatic tremor in 30 patients. The findings indicate that orthostatic tremor is distinct from essential tremor, both clinically and electrophysiologically. The major differences are the frequency of electromyographic burst firing, the invariable involvement of lower limb and paraspinal muscles, and the task‐specific nature of the tremor in orthostatic tremor. The study shows that the diagnosis can be established rapidly with surface electromyographic recordings. © 1993 John Wiley & Sons, Inc.
Acute Lyme neuropathy presenting with polyradicular pain, abdominal protrusion, and cranial neuropathy
Authors: Krishnamurthy Kaarkuzhali B. , Liu Grant T. , Logician Eric L. 
Published: January 2005

AbstractA 53‐year‐old man developed multifocal radicular pain. The diagnosis of Lyme neuroborreliosis was delayed until bifacial paresis and right lower abdominal wall weakness developed, prompting further evaluation. Cerebrospinal fluid (CSF) examination showed aseptic meningitis. Antibodies directed against Borrelia burgdorferi were present in the serum; higher tilers were present in the CSF, indicating local antibody production. Electrophysiologic studies showed both an axonal polyradiculopathy as well as demyelinative facial palsy. Ceftriaxone therapy led to marked improvement in pain and facial palsies. © 1993 John Wiley & Sons, Inc.
The influence of changes in the intensity of magnetic stimulation on coil output
Authors: Reutens David C. , Macdonell Richard A. L. , Berkovic Samuel F. 
Published: January 2005

AbstractWe measured the peak voltage induced in a sensing loop by a Magstim 200 magnetic stimulator. Coil output varied little for repeated stimulation at the same intensity over a wide range of coil output. In contrast, the first stimulus immediately after a change in intensity was of larger amplitude and showed greater variability than subsequent stimuli. The effect was seen for changes in intensity of 5% and 60% and was greater for reductions than for increases in stimulation intensity. Stimulation immediately after a reduction in intensity from 100% to 40% resulted in peak induced voltages as high as those recorded for repeated stimulation at 43% of maximum coil output. Increased coil output following changes in stimulation intensity may affect measurement of the threshold for motor cortical stimulation. The effect of a change in intensity could be minimized by delaying stimulation for at least 30 s or discarding the first stimulus after the change. © 1993 John Wiley & Sons, Inc.
Dystrophin–glycoprotein complex: Its role in the molecular pathogenesis of muscular dystrophies
Authors: Matsumura Kiichiro , Campbell Kevin P. 
Published: January 2005

AbstractDystrophin, the protein product of the Duchenne muscular dystrophy (DMD) gene, is associated with a large oligomeric complex of sarcolemmal glycoproteins, including dystroglycan which provides a linkage to the extracellular matrix component, laminin. In patients with DMD, the absence of dystrophin leads to the loss in all of the dystrophin‐associated proteins, causing the disruption of the linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. This may render the sarcolemma vulnerable to physical stress. These recent developments in the research concerning the function of the dystrophin–glycoprotein complex pave a way for the better understanding of the pathogenesis of muscular dystrophies. © 1994 John Wiley & Sons, Inc.