bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single‐fiber electromyography in neuromuscular disorders: Correlation of muscle histochemistry, single‐fiber electromyography, and clinical findings
Authors: Bertorini Tulio E. , Stalberg Erik , Yuson Carlo P. , Engel W. King 
Published: January 2005

AbstractWe performed single‐fiber electromyography (SFEMG) and correlated the results with muscle‐biopsy histochemistry in 56 patients with various neuromuscular diseases. Increased muscle‐fiber density, delineated by SFEMG, was most prominent in diseases of ordinary denervation, namely motor neuron disorders and peripheral neuropathies, and it correlated with histochemical fiber type grouping. Both phenomena reflect denervation followed by reinnervation. In patients with central core disease and rod disease, fiber density was not increased despite massive type I fiber predominance. The normal distribution of type I fiber subtypes in those patients indicated that their fiber predominance was not due to sprouting and reinnervation, but probably to paucity of the type II fibers. In type I fiber hypotrophy with central nuclei, fiber density was increased, perhaps attributable to the small diameter and consequent denser packing of the type I fibers. Fiber density was slightly increased in the majority of patients with acidmaltase deficiency, limb‐girdle dystrophy, and polymyositis, in nearly half with mitochondrial myopathy, and in 1 older Duchenne dystrophy patient. In these myopathic disorders, myogenous deinnervation (followed by reinnervation) is one possible explanation. Normal fiber density was present in all patients with muscle phosphorylase deficiency, myotonia congenita, and in the hypokalemic periodic paralysis patients under age 40. © 1994 John Wiley & Sons, Inc.
Outliers, a way to detect abnormality in quantitative EMG
Authors: Stålberg Erik , Bischoff Christian , Falck Björn 
Published: January 2005

AbstractIn visual analysis of motor unit potentials it is common to decide abnormality by a few motor unit potentials with definitely abnormal amplitude, duration, and shape. The aim of the present investigation was to define limits of normal values and to compare the diagnostic yield of assessing definitely abnormal values outliers, with conventional mean values of MUP parameters. MUPs were extracted and measured with a new decomposition method. Reference values were obtained for three commonly studied muscles. Patients with various types of neuropathies and myopathies were studied in the same way with measurement of outliers and mean values. It was found that outliers were as sensitive as mean values in neuropathies and better in myopathies. Often an increased number of outliers could already be detected after only a few MUPs had been obtained. It would not have been necessary to obtain all 20 MUPs in these patients. The conclusion is that the outlier method is as sensitive as mean values. Because the number of MUPs required may be reduced, the investigation takes a shorter time and is less painful for the patient. If the degree of abnormality is to be quantified, calculation of mean values is still necessary. The combination of outliers and mean values may be the optimal way to detect and express abnormality. © 1994 John Wiley & Sons, Inc.
Absent F‐waves early in a of transverse myelitis
Authors: Syme Jackie A. , Kelly John J. 
Published: January 2005

AbstractA 29‐year‐old female presented with acute onset of interscapular pain, followed by weakness of both legs and both hands, and a thoracic sensory level. F‐waves in her legs and arms were absent initially, but other conduction studies were normal. An initial spine MRI was normal but a second study 10 days later revealed an enlarged spinal cord with areas of enhancement. Repeat neurophysiologic studies showed return of F‐waves in the legs and absent compound muscle action potential (CMAP) in the hands with early denervation on needle examination. An acute intraxial lesion needs to be included in the differential diagnosis of absent F‐waves. © 1994 John Wiley & Sons, Inc.
H reflex studies in cerebral palsy patients undergoing partial dorsal rhizotomy
Authors: Logigian Eric L. , Wolinsky Joel S. , Soriano Sulpicio G. , Madsen Joseph R. , Scott R. Michael 
Published: January 2005

AbstractH reflex studies were performed in ten spastic children with cerebral palsy who underwent partial dorsal rhizotomy (PDR). Under anesthesia prior to PDR, H reflex amplitude evoked by percutaneous peripheral nerve stimulation gradually declined in all patients and became unobtainable in five. Motor responses could still be evoked by apparent dorsal root stimulation in these five, but since it was shown that they were M responses and not reflexes, PDR was performed randomly. In the other five patients, in whom H reflexes were still evokable, dorsal root stimulation evoked motor responses which were true reflex responses, and PDR was performed “selectively.” Compared to preoperative values, postoperative Hmax/Mmax ratios declined, but no more so in selective than in random PDR. We conclude that current intraoperative methods for selection of “abnormal” dorsal rootlets for section may be invalid and may have no bearing on successful outcome, since spasticity improves even with random PDR. © 1994 John & Sons, Inc.
Association between muscle architecture and quadriceps femoris H‐reflex
Authors: Garland S. Jayne , Gerilovsky Lubomir , Enoka Roger M. 
Published: January 2005

AbstractThe purpose of the present study was to establish the relationship between muscle architecture and H‐reflex recordings in quadriceps femoris muscle. H‐reflexes were elicited in human quadriceps femoris muscle over a broad area of skin to document the shape and amplitude of the H‐potentials. This, in combination with recording monopolar and bipolar H‐potentials, was performed to determine the location and method for measuring maximum‐amplitude H‐reflexes. The influence of neural and peripheral factors on the H‐potential during passive length changes was studied by comparing the amplitude of H‐potentials to motor unit action potentials. Monopolar recordings of the H‐potential were found to be preferable to bipolar recordings because of the reproducibility of shape and easier distinction between the M‐ and H‐potentials. The location for recording maximum H‐potentials was in the distal one third of the quadriceps femoris muscle, over the border between vastus lateralis and rectus femoris. The inferred relationship between H‐potential amplitude and reflex excitability must be made with caution in quadriceps femoris muscle because the amplitude of both the motor unit potential and H‐potential change as a function of muscle length. © 1994 John Wiley & Sons, Inc.
Satellite cell activity is required for hypertrophy of overloaded adult rat muscle
Authors: Rosenblatt J. David , Yong David , Parry David J. 
Published: January 2005

AbstractHypertrophy of extensor digitorum longus muscle, overloaded by the removal of the synergist tibialis anterior (TA) muscle, in growing rats is inhibited if endogenous satellite cells are sterilized by exposure to irradiation. However, normal muscle growth is not eliminated, only diminished. To test whether irradiated, overloaded muscle can hypertrophy in the absence of normal growth‐related stimuli, experiments were conducted on mature rats. TA muscle ablation caused hypertrophy of EDL muscle, characterized by a significant increase in muscle mass and the size of type IIx and type IIb fibers, and a proportional increase the number of myonuclei. When ablation was preceded by irradiation hypertrophy did not occur. The results indicate that satellite cell activation, division, and fusion is necessary for compensatory hypertrophy of fully mature muscle, and may be important to the understanding of the limits of recovery of inherited muscle myopathies treated by myogenic cell implantation. © 1994 John Wiley & Sons, Inc.
Ophthalmoplegia, demyelinating neuropathy, leukoencephalopathy, myopathy, and gastrointestinal dysfunction with multiple deletions of mitochondrial DNA: A mitochondrial multisystem disorder in search of a name
Authors: Uncini Antonino , Servidei S. , Silvestri G. , Manfredi G. , Sabatelli M. , di Muzio A. , Ricci E. , Mirabella M. , di Mauro S. , Tonali P. 
Published: January 2005

AbstractThis article describes a 37‐year‐old woman with progressive external ophthalmoplegia, peripheral neuropathy, and chronic intractable diarrhea. Laboratory studies disclosed lactic acidosis, ragged red fibers lacking cytochrome c oxidase, high‐normal muscular mitochondrial enzymes, demyelinating neuropathy, leukoencephalopathy and multiple mitochondrial DNA deletions. This is the fourth patient described with this clinical syndrome, which represents a separate entity among multisystemic mitocnondrial disorders. The patient described here is the first with this syndrome to have multiple mitochondrial DNA deletions. © 1994 John Wiley & Sons, Inc.
The dropped head syndrome with chronic inflammatory demyelinating polyneuropathy
Authors: Hoffman Donald , Gutmann Ludwig , Griggs Robert C. , Mendell Jerry R. , Miller Robert G. 
Published: January 2005

AbstractThe dropped head syndrome occurs in a variety of neuromuscular disorders. We present a woman with chronic inflammatory demyelinating polyneuropathy who developed this syndrome, likely reflecting severe demyelination of nerves to cervical paraspinal muscles. © 1994 John Wiley & Sons, Inc.
Physiological properties of single thenar motor units in the F‐response of younger and older adults
Authors: Doherty Timothy J. , Komori Tetsuo , Stashuk Daniel W. , Kassam Ariff , Brown William F. 
Published: January 2005

AbstractThe purpose of this study was to characterize the properties of single thenar motor units in the F‐response of healthy younger (n = 15; age 33 = 11 years) and older subjects (n = 15: age 68 = 3 years). Trains of 300 stimuli at intensities evoking M‐potentials 10%, 20%, and 30% of the peak‐to‐peak amplitude of the maximum M‐potential, were delivered to the median nerve. In the young, observed firing probabilities of surfacedetected motor unit action potentials (S‐MUAPs) extracted from the F‐response ranged from less than 1–10%, the S‐MUAPs varied in size from 0.015% to 5.3% of the maximum M‐potential negative peak area, and they were similar in size to the population of S‐MUAPs collected by multiple point stimulation of the median nerve. The percentage difference between the slowest and fastest conducting fibers for individual subjects ranged from 8% to 20%, which translated to conduction velocities (CVs) of 48–68 m · s−1 (mean 59 ± 4). The preceding were all independent of stimulus intensity. The S‐MUAP sizes were significantly larger in older subjects (39%), and the range and distribution of motor unit CVs (38–61 m · s−1; mean 52 ± 3) were markedly shifted to reflect a slower population of motor fibers. These findings suggest that age‐related axonal slowing may uniformly affect all median motor fibers. © 1994 John Wiley & Sons, Inc.
Motor unit number estimates based on the automated analysis of F‐responses
Authors: Stashuk Daniel W. , Doherty Timothy J. , Kassam Ariff , Brown William F. 
Published: January 2005

AbstractAn automated technique for estimating the number of motor units based on single motor unit action potentials in the F‐response is described. The average surface detected motor unit action potential (SMUAP) was calculated from the datapoint‐by‐datapoint average of a sample of S‐MUAPs automatically selected from a population of F‐responses. The technique was applied to the thenar muscles of young (n = 18, aged 31 ± 11 years) and older (n = 15, aged 68 ± 3) subjects, Motor unit number estimates based on the automated selection of S‐MUAPs from the F‐responses compared well with those derived using a computer‐assisted manual method for selecting S‐MUAPs from the F‐response (automated 245 ± 105 vs. manual 241 ± 100, r = 0.93) and were similar to estimates obtained using multiple point stimulation (219 ± 77). The advantages of the automated technique for collecting S‐MUAPs from the F‐response include the ready tolerance of the technique by subjects, the minimal amount of operator interaction required, and the additional information relating to the conduction velocities and latencies of single motor axons. © 1994 John Wiley & Sons, Inc.
Metabolic and nonmetabolic components of fatigue monitored with 31P‐NMR
Authors: Baker Anthony J. , Carson Paul J. , Miller Robert G. , Weiner Michael W. 
Published: January 2005

AbstractThe goal of this study was to determine the roles of metabolic and nonmetabolic factors in muscle fatigue. Rat gastrocnemius muscles were fatigued by stimulation of the nerve (n = 6) or muscle (n = 4, after 2 days of denervation). 31Phosphorus nuclear magnetic resonance spectroscopy was used to measure levels of intracellular inorganic phosphate (Pi) and hydrogen ions (H+) (which are thought to inhibit contraction) and the high‐energy phosphates, phosphocreatine (PCr), and ATP. For both indirect and direct stimulation, with fatigue to ≈60% initial tetanic force, [Pi] increased from ≈3.5 mmol/L to ≈20 mmol/L and [PCr] decreased from ≈27 mmol/L to ≈9 mmol/L. However, with continued fatigue to 25–35% initial tetanic force, neither [Pi] or [PCr] changed further. [ATP] and pH changed only slightly during fatigue. The results are consistent with early fatigue arising from metabolic inhibition of contraction; but later fatigue arising independent of metabolites, due to impaired activation beyond the neuromuscular junction. © 1994 John Wiley & Sons, Inc.
Assessment of variability in the shape of the motor unit action potential, the “jiggle,” at consecutive discharges
Authors: Stålberg Erik V. , Sonoo Masahiro 
Published: January 2005

AbstractA method for quantifing shape variability, the jiggle, of motor unit potentials (MUPs) recorded with conventional EMG electrodes is presented. Amplitude variability at each point of time of the MUP was analyzed. Two new parameters are proposed: the normalized value of the consecutive amplitude differences (CAD), and the crosscorrelational coefficient of the consecutive discharges (CCC). Simulations showed that increased jitter of the constituent single fiber potentials increases the jiggle as expressed by an increase in CAD and decrease in CCC values. Even when the jitter value of each component was fixed, increased temporal dispersion increased the jiggle whereas an increased number of fibers decreased the jiggle. This new method has been applied in normal subjects, patients with chronic neurogenic diseases and patients with ALS. Jiggle was significantly increased in the ALS group, in agreement with visual observations. We believe that this method for quantifying jiggle will increase the information obtainable from routine EMG investigations. © 1994 John Wiley & Sons, Inc.
Autonomic involvement in Guillain–Barre syndrome: A review
Authors: Zochodne Douglas W. 
Published: January 2005

AbstractAutonomic neuropathy is an important and common complication of Guillain‐Barré syndrome (GBS). Manifestations be present in cardiovascular, sudomotor, gastrointestinal and other systems involving both sympathetic and parasympathetic fibers. Some apparently selective acute autonomic neuropathies may be subvarieties of GBS. Experimental work in animal models, pathological studies of GBS patients, and autonomic function studies have provided some help in the understanding of this complication. In managing GBS patients with autonomic dysfunction there are important practical considerations that can improve their care. In this article we review the literature on autonomic neuropathy in GBS and propose a management scheme to accommodate it in the overall treatment of the neuropathy. © 1994 John Wiley & Sons, Inc.
Phonomyogram of the diaphragm during unilateral and bilateral phrenic nerve stimulation and changes with fatigue
Authors: Petitjean Michel , Bellemare Francois 
Published: January 2005

AbstractAs previously demonstrated in humans, contracting skeletal muscles vibrate laterally and generate sound. The amplitude of this acoustic signal, called the phonomyogram (PMG), is related to muscle force production. As in limb muscles, the diaphragm might produce mechanical tissue vibrations and a PMG. We recorded diaphragm twitches during phrenic nerve stimulation in normal subjects at FRC. Diaphragmatic compound motor action potentials (CMAP) were recorded on each side of the chest by surface electrodes over the eighth intercostal space. Condenser microphones were fixed to the skin close to the electrodes, and esophageal and gastric balloons employed to measure transdiaphragmatic pressure (Pdi). For unilateral and bilateral supramaximal single shocks (O.1 ms), PMG onset latencies from either side (12.4 ± O.6 ms) were intermediate between those of CMAP (7.3 ± O.7 ms) and of Pdi (20.3 ± 2.8 ms). By varying stimulation intensity, significant linear relationships were obtained between CMAP and PMG amplitudes on each side. A significant linear relationship was also found between PMG for each side and Pdi peak values. PMG and Pdi both decreased with fatigue of the diaphragm. We conclude that PMG in response to single phrenic nerve shocks is a noninvasive index of electromechanical coupling, recruitment, and transdiaphragmatic pressure generation by the diaphragm. © 1994 John Wiley & Sons, Inc.
Brainstem reflexes in patients with olivopontocerebellar atrophy
Authors: Valls‐Solé Josep , Lou Jau‐Shin , Hallett Mark 
Published: January 2005

AbstractIn 4 patients with familial olivopontocerebellar atrophy (OPCA) we have recently described an abnormal movement of facial muscles characterized by rhythmic muscle twitching during voluntary activation (facial action myoclonus). In the present article, we present the results of a neurophysiologicel study of brainstem reflexes in those 4 patients, in 4 other patients with OPCA but without facial action myoclonus, in 3 patients with pure cerebellar cortical atrophy, and in 6 normal volunteers used as control subjects. All patients had similar clinical features, but only the patients with facial action myoclonus and only one of the other patients with OPCA had brainstem atrophy detected on magnetic resonance imaging. Electrophysiological abnormalities were found in all patients with facial action myoclonus and consisted of myokymia in perioral muscles at rest, spread of spontaneous and reflex blinking to the orbicularis oris, and enhanced long‐latency facial reflex responses to stimuli applied to the facial or trigeminal nerve. Other relevant electrophysiological abnormalities were the absence of jaw jerk in 2 patients, the absence of an R1 response of the blink reflex in 1 patient, and a markedly reduced compound muscle action potential of the facial nerve in another patient. Comparable electrophysiological abnormalities were found in only 1 of the patients with OPCA but without facial action myoclonus, and in none of the patients with pure cerebellar cortical atrophy. Facial action myoclonus is a clinical manifestation of a global brainstem functional derangement that may characterize a subgroup of patients with OPCA or constitute a distinctive step in the natural evolution of some forms of the disease. © 1994 John Wiley & Sons, Inc.
Limb girdle muscular dystrophy: Description of a phenotype
Authors: StüBgen Joerg‐Patrick 
Published: January 2005

AbstractThe phenotype is reported of 20 patients with autosomal recessive or sporadic, pelvifemoral limb girdle muscular dystrophy (LGMD). Selective wasting of muscles was observed at the moderately advanced stage of illness. The pattern of weakness was uniform. Attention to clinical detail allowed the identification of a phenotype different from a hypothetical scheme of LGMD based on previous literature, and other causes of limb girdle weakness. These patients may represent yet another nosologic entity within the autosomal recessive dystrophies; molecular genetic studies are awaited. A limited magnetic resonance imaging (MRI) study of muscle was of little consequence. Although additional detail was obtained, no pathognomonic distribution of the dystrophic process was observed; interindividual variation existed even among closely matched siblings. The severity of MRI signal change did not consistently correlate with the degree of weakness in an individual. When a diagnosis is uncertain, however, the added detail may be useful. © 1994 John Wiley & Sons, Inc.
Mixed nerve action potentials in acquired demyelinating polyneuropathy
Authors: Luciano Carlos A. , Gilliatt Roger W. , Conwit Robin A. 
Published: January 2005

AbstractUncertainty about motor and sensory contributions in abnormal nerves has limited the use of mixed nerve action potentials (MNAPs). We recorded MNAPs in 21 patients with an acquired demyelinating neuropathy, 18 age‐matched control subjects, and 10 patients with an axonal polyneuropathy. Bipolar and unipolar recordings from median and ulnar nerves were made above the elbow after electrical stimulation of the nerves at the wrist. Antidromic digital sensory action potentials and motor conduction velocity were also recorded for both nerves. In 19 median and 12 ulnar nerves from demyelinating polyneuropathy patients, compared with control subjects, MNAP amplitudes were significantly reduced (mean, 6 μV vs. 31 μV), MNAP velocities were mildly reduced (mean, 50 m/s vs. 62 m/s), motor conduction velocities were significantly reduced (mean, 33 m/s vs. 57 m/s), and MNAPs were significantly dispersed, with markedly prolonged rise times (mean, 2.0 ms vs. 1.0 ms). Compared with the axonal polyneuropathy group, MNAP amplitudes from the median nerve were similarly reduced (mean, 8 μV vs. 9 μV), MNAP velocities were only slightly slower (mean, 52 m/s vs. 58 m/s), but the rise times were significantly prolonged (mean, 2.0 ms vs. 1.2 ms). We conclude that, in acquired demyelinating neuropathies, the onset and, in some cases, the whole MNAP is from afferent fibers, which can be abnormally dispersed, and that, over the same segment, MNAP velocity is less affected than motor conduction velocity. 1995.© 1995 John Wiley &Sons, Inc.
Influence of baclofen upon the alpha‐motoneuron in spasticity by means of f‐wave analysis
Authors: Dressnandt Jürgen , Auer Carola , Conrad Bastian 
Published: January 2005

AbstractIntrathecal baclofen dramatically improves severe spastic syndromes. This improvement is likely related to reduced excitability of alphamotoneurons. To investigate the influence of baclofen upon the alphamotoneuron, we analyzed F‐waves before and after intrathecal baclofen bolus injection (usually 50 μg) as well as after administration of different, constantly delivered doses (60–200 μg/day). Intrathecal baclofen bolus decreased the maximum F‐wave amplitude (Fp) from an initial value of 9% of the maximum M amplitude (Mmax) (=F/M‐ratio) to 2.4% of the Mmax after 130–180 min, reduced the mean F‐wave amplitude 60% within 150 min, and shortened the mean duration by 40–60% after 130–180 min. Constantly delivered baclofen of 100 μg/day reduced the F/M‐ratio from 5% to 2%, the mean F‐wave amplitude by 40–80%, and the F‐wave mean duration by 40–80%. The minimum F‐wave latency did not change after bolus or during steady state administration. The findings indicate that the F‐wave mean and maximum amplitude as well as the mean duration are altered in a quantifiable manner following intrathecal baclofen application.© 1995 John Wiley &Sons, Inc.