bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of vibrotactile thresholds with physical examination and electrophysiological assessment
Authors: Gerr Fredric , Letz Richard , Hershman Dawn , Farraye Joseph , Simpson David
Published: January 2005

Measurement of cutaneous vibrotactile thresholds may be useful for assessment of the functional integrity of the somatosensory system. To validate a rapid method of determining vibrotactile thresholds that uses a commercially available electromechanical device, vibrotactile thresholds were compared with standardized physical examination findings of sensory function and electrophysiological parameters in 79 patients referred to the Mount Sinai Hospital Neurophysiology Laboratory for clinical electrophysiological evaluation. A statistically significant monotonic association between graded physical examination of vibration perception and vibrotactile threshold was observed for all digits tested in the upper and lower extremities. Statistically significant associations were also observed between vibrotactile thresholds and a variety of electrophysiological measures of the median, ulnar, tibial, peroneal, and sural nerves. The strongest associations were observed between great toe vibrotactile thresholds and late response latencies measured in nerves in the lower extremities. Determination of vibrotactile thresholds may be useful in settings where quantitative measures of large fiber nerve function are desirable and electrophysiological study is not feasible.
Interobserver agreement in the assessment of muscle strength and functional abilities in Guillain‐Barré syndrome
Authors: Kleyweg Ruud P. , Van Der Meché Frans G. A. , Schmitz Paul I. M.
Published: January 2005

In studies of Guillain‐Barré syndrome, functional deficit is usually assessed according to a functional scale consisting of several categories. The level of interobserver agreement in this scoring method is not known; furthermore, this method seems to be insensitive when applied to bedridden and artificially ventilated patients. We have developed an additional score (MRC‐sumscore), reflecting muscle strength in general. Both scoring methods, tested in Guillain‐Barré patients, have an almost perfect interobserver agreement. For the functional score k = 0.85, and for the MRC‐sumscore r2 = 0.96. The MRC‐sumscore is easily assessed and more sensitive than the functional score when patients are bedridden or artificially ventilated.
Myopathy with thick filament (myosin) loss following prolonged paralysis with vecuronium during steroid treatment
Authors: Danon Moris J. , Carpenter Stirling
Published: January 2005

A 20‐year‐old female hospitalized with status asthmaticus was treated with bronchodilators, antibiotics, and high‐dose corticosteroids, and was paralyzed with vecuronium for 10 days to facilitate mechanical ventilation. When this was discontinued, she was found to have a flaccid quadriplegia with areflexia and 4‐fold elevation in serum creatine kinase. A muscle biopsy showed extensive loss of thick (myosin) myofilaments, sometimes in corelike distribution, with relative preservation of thin (actin) filaments and Z‐discs. Muscle strength returned to normal after 2 months. The pathological lesion in this patient's muscle fibers resemble those in rats treated with high doses of corticosteroids following denervation.
Anconeus muscle: A human muscle preparation suitable for in‐vitro microelectrode studies
Authors: Maselli Ricardo A. , Mass Daniel P. , Distad Barbara J. , Richman David P.
Published: January 2005

We performed in‐vitro microelectrode studies on the anconeus muscle of 14 patients with diseases of neuromuscular transmission. The procedure detected marked abnormalities in all patients studied, and may therefore be a valuable technique for the study of human disorders of neuromuscular transmission.
Estimation of conduction velocity of Aδ fibers in humans
Authors: Kakigi Ryusuke , Endo Chiyoko , Neshige Ryuji , Kuroda Yasuo , Shibasaki Hiroshi
Published: January 2005

Conduction velocity of Aδ fibers of the human peripheral nerves was measured by using pain‐related somatosensory evoked potentials following CO2 laser stimulation. It was found to be approximately 9 m/s in the forearm as well as in the lower leg. Because conventional conduction study using electric stimulation reflects only functions of large myelinated fibers related to deep proprioceptive and tactile sensations, the present noninvasive and simple, novel method is the only laboratory examination currently available to investigate physiological functions of the small diameter fibers mediating pain‐temperature sensations.
High pancuronium sensitivity of axonal nicotinic‐acetylcholine receptors in humans during organophosphate intoxication
Authors: Besser Roland , Vogt Thomas , Gutmann Ludwig , Wessler Ignaz
Published: January 2005

The effect of low‐dose pancuronium on neuromuscular transmission was studied in 2 patients during the early and late stages of severe organophosphate intoxication. Single evoked compound muscle action potentials (CMAP) were followed by repetitive discharges and a decrement‐increment (D‐l) phenomenon with 10‐, 20‐, and 50‐Hz supramaximal nerve stimulation. Intravenous pancuronium, 1 mg, abolished the D‐l phenomenon, while the repetitive discharges of the CMAP were only partially reduced. It is postulated, that the disappearance of the D‐l phenomenon with persistence of the CMAP repetitive discharges results from blockade of nicotinic‐acetyl‐choline receptors located on the terminal axon responsible for stimulus‐induced antidromic backfiring. This response to a very low dose of pancuronium indicates a high sensitivity of the axonal nicotinic‐acetylcholine receptor to pancuronium in humans, as had been previously postulated from animal experiments.
Abnormalities in the sensory action potential in patients with amyotrophic lateral sclerosis
Authors: Shefner Jeremy M. , Tyler H. Richard , Krarup Christian
Published: January 2005

Sensory function in patients with amyotrophic lateral sclerosis (ALS) is thought to be normal; however, there is convincing morphologic evidence that sensory systems are affected in addition to motor systems. In this study, compound sensory action potentials were recorded with near nerve electrodes from 18 patients with ALS. Up to 1024 responses were averaged at high gain to determine minimum conduction velocity; that is, the conduction velocity of the slowest conducting component of the sensory action potential. Nine of 18 patients had abnormally reduced minimum conduction velocity, even when peak‐to‐peak amplitude and maximum conduction velocity (calculated from the latency to the initial positive peak) were normal. Only 3 of 18 patients showed abnormalities in peak‐to‐peak amplitude. Thus, subtle abnormalities in the sensory action potential can be detected in many patients with ALS.
Interindividual variability of central delay changes in the soleus H reflex pathway
Authors: Abbruzzese Michele , Reni Lizia , Favale Emilio
Published: January 2005

Central delay (CD) changes in the soleus H reflex pathway, as demonstrated by variations in the time interval between afferent (P1) and efferent (P2) neurographic volleys underlying the reflex response, were assessed in a group of normal subjects, both during the steady state and after homosynaptic spatial summation of afferent impulses. The maximal range of CD changes, regardless of whether “spontaneous” or provoked, showed significant interindividual differences whose size was positively related to the Hmax/Mmax ratio, provided that the extension of the subliminal fringe was suitably normalized. Comparatively similar variations in amplitude of the reflex motoneuronal discharge under different experimental conditions can be associated with different CD changes. Indeed, “spontaneous” CD fluctuations occurring during the steady state were consistently greater than CD reductions provoked by spatial summation, the gap size being negatively related to the Hmax/Mmax ratio.
Single fiber EMG reference values: A collaborative effort
Authors:   Ad Hoc Committee of The AAEM Special Interest Group on Single Fiber EMG, Gilchrist James M.
Published: January 2005

Single fiber electromyography (SFEMG) measurements of fiber density and jitter are used in the diagnosis of a variety of peripheral nervous system disorders. However, the normal values of these measurements for most muscles and age groups are not well documented in the literature. We present a retrospective and prospective multicenter collection of SFEMG jitter and fiber density data from control subjects obtained for the purpose of defining reference values for many muscles and different ages. The data and calculated upper limits for fiber density, individual pair jitter, and mean jitter are presented for each muscle in tabular and graphical format, for different age groups.
The function of large and small nerve fibers in renal failure
Authors: Angus‐Leppan Heather , Burke David
Published: January 2005

Previous clinical and neurophysiological studies of uremic neuropathy have focused almost exclusively on the function of large sensory and motor axons. The sensations of heat and cold depend on the function of unmyelinated afferents and small myelinated afferents, respectively, and these sensations can be quantified using a standardized psychophysical technique. Thermal thresholds were measured in 20 patients with end‐stage renal failure to determine the extent of small afferent fiber involvement and to compare this with the clinical and electrophysiological evidence of large fiber involvement. Whereas abnormalities of standard nerve conduction studies were found in 16 patients, abnormal thermal thresholds were found in only 6 patients. In the nerve conduction studies, the amplitudes of nerve potentials were reduced more than their conduction velocities, consistent with an axonopathy. This study found little evidence of significant dysfunction of small afferent fibers in end‐stage renal failure and, when such changes occurred, they did not correlate with the clinical evidence of polyneuropathy. The functional sparing of axons of small diameter is consistent with the relative sparing of these axons in pathological studies.
Improved inching method for the diagnosis and prognosis of carpal tunnel syndrome
Authors: Imaoka H. , Yorifuji S. , Takahashi M. , Nakamura Y. , Kitaguchi M. , Tarui S.
Published: January 2005

A modified sensory “inching” method for the electrodiagnosis of carpal tunnel syndrome (CTS) Is described. The median nerve as stimulated at the cubital portion, with 8 channel recording electrodes placed along the nerve across the carpal tunnel. In most of the CTS cases, there was a conductive abnormality from 3 to 4.5 cm distal to the proximal ending of the flexor retinaculum. Subjects'; values, obtained by subtracting the theoretical latency from the measured latency, which were more than 0.6 ms, could not be improved by conservative therapy. As we could determine from subtle change at the short span of nerve condcution, below the electrodes from the proximal to the affected site of the carpal tunnel, this method provides high sensitivity and specificity for the diagnosis of CTS.
Growth and development of human muscle: A quantitative morphological study of whole vastus lateralis from childhood to adult age
Authors: Lexell Jan , Sjöström Michael , Nordlund Ann‐Sofie , Taylor Charles C.
Published: January 2005

The mechanisms underlying the increase in volume of muscle tissue, and the functional development of muscle fibers from childhood through adolescence to adult age, have been studied. Cross sections of autopsied whole vastus lateralis muscle from 22 previously physically healthy males, 5 to 37 years of age, were prepared enzyme histochemically (myofibrillar ATPase) and examined morphometrically. The data obtained on muscle crosssectional area, size, total number, and proportion of type 1 (slow‐twitch) and type 2 (fast‐twitch) fibers were analyzed using linear regression techniques. The results show that the increase in muscle cross‐sectional area from childhood to adult age is caused by an increase in mean fiber size. This is accompanied by a functional development of the fiber population: the proportion of type 2 fibers increases significantly from the age of 5 (approx. 35%) to the age of 20 (approx. 50%), which, in the absence of any discernible effect on the total number of fibers, is most likely caused by a transformation of type 1 to type 2 fibers.
Comparison of electric and magnetic coil stimulation in the supraclavicular region
Authors: Cros Didier , Gominak Stasha , Shahani Bhagwan , Fang Jianjun , Day Bruce
Published: January 2005

We compared the compound motor action potentials (CMAPs) evoked in the biceps, triceps, and abductor digiti minimi (ADM) muscles by conventional electrical stimulation at Erb's point (EP), and by magnetic coil stimulation of the supraclavicular region in 11 normal subjects. We found that magnetic coil stimulation was less effective than conventional stimulation in activating motor fibers in the brachial plexus in 45% of the recordings analyzed. CMAP amplitudes greater than those obtained with EP electrical stimulation were seen in 16% of recordings with supraclavicular magnetic stimulation, and in 33% of recordings with cervical magnetic stimulation, indicating that EP electrical stimulation is submaximal in a large proportion of cases.
Single motor unit H‐reflex in motor neuron disorders
Authors: Soliven Betty , Maselli Ricardo A.
Published: January 2005

The latency fluctuation of single motor unit potentials (MUPH) in the H‐reflex is greater than the latency fluctuation of MUPs in the direct (MUPM) and recurrent (MUPF) responses. This has been attributed to the variability in the impulse generation at the site of nerve stimulation, and to the variation in the synaptic delay at the anterior horn cell. We studied the latency fluctuation of single motor unit H‐reflex in patients with motor neuron disorders (MND) in comparison with normal subjects. The mean jitter of the H‐reflex was 264.3 ± 17.8 μs (mean ± SEM) in 30 MUPH recorded from 10 patients with ALS, 302.7 ± 25.2 μs in 16 MUPH from 6 patients with chronic motor neuron diseases, as compared with 137.4 ± 7.3 µs in 34 MUPH recorded from 10 normal subjects. This difference, which persisted even after the correction for the latency variation of MUPM, cannot be explained on the basis of an enhanced reciprocal inhibition. Thus, the increased latency fluctuation of the single motor unit H‐reflex in patients with MND may reflect changes in the motoneuron pool excitability that may be secondary to altered intrinsic electrophysiological properties of motoneurons, or to an abnormal temporal and spatial summation of synaptic inputs on motoneurons.
Distal small fiber neuropathy: Results of tests of sweating and autonomic cardiovascular reflexes
Authors: Stewart John D. , Low Phillip A. , Fealey Robert D.
Published: January 2005

The purpose of this study was to evaluate sweating and cardiovascular autonomic function in patients with distal small fiber neuropathy (DSFN). Sweat testing by the quantitative sudomotor axon reflex test was abnormal in 32 of 40 (80%) patients. The thermoregulatory sweat test was abnormal in 18 of 25 (72%) patients; one or both tests were abnormal in 36 of 40 (90%). Minor heart rate abnormalities were present in 11 of 40 (28%) patients. We conclude that, in patients with DSFN: (a) the sympathetic sudomotor fibers are frequently affected, and that evaluation of sweating is a useful diagnostic test; (b) that the autonomic nerves controlling heart rate are less affected.
Wallerian degeneration in human nerves: Serial electrophysiological studies
Authors: Chaudhry Vinay , Cornblath David R.
Published: January 2005

After nerve transection, the distal stump undergoes Wallerian degeneration (WD). Little information is available concerning sequential changes in nerve conduction measurements during WD in humans. Five patients with nerve injuries were studied temporally. Motor‐evoked amplitudes were reduced by 50% at 3 to 5 days after injury; the response was absent by day 9. Sensory‐evoked amplitudes were reduced by 50% at 7 days after injury; the response was absent by day 11. Sensory and motor nerves with shorter distal stumps showed earlier loss of amplitude than did those with longer distal stumps. Denervation potentials were seen 10 to 14 days after injury. Our results suggest that WD occurs earlier if the distal stump is shorter, and that motor‐evoked responses are affected earlier than sensory‐evoked responses. The time‐lag between the loss of the motor‐evoked response and the appearance of denervation potentials, the latter coinciding with reduction of sensory evoked responses, suggests that failure of neuromuscular transmission precedes axonal loss during WD.
Diagnostic sensitivity of the laboratory tests in myasthenia gravis
Authors: Oh Shin J. , Kim Doo E. , Kuruoglu R. , Bradley Ronald J. , Dwyer Donard
Published: January 2005

The diagnostic sensitivity of three laboratory tests [serum antiacetylcholine receptor antibody (AChR‐ab) assay, the repetitive nerve stimulation (RNS) test, and, the single fiber EMG (SFEMG)] for myasthenia gravis (MG) was compared in 120 patients. In all cases, at least one of the tests was abnormal. SFEMG was the most sensitive test, being abnormal in 92% of cases, followed by the RNS test (77%) and the AChR‐ab assay (73%). SFEMG was abnormal in all cases with negative ACHR‐ab and RNS tests, in 97% of cases with negative AChR‐ab assay, in 89% of cases with negative RNS test, and in 89% of cases with mild MG. We conclude that one of these three tests is abnormal in all cases of MG, and that the SFEMG is most sensitive in the diagnosis of MG.
Improved medium with EGF and BSA for differentiated human skeletal muscle cells
Authors: St. Clair Judy A. , Meyer‐Demarest Sarah D. , Ham Richard G.
Published: January 2005

Epidermal growth factor (EGF) and bovine serum albumin (BSA) are both required for serum‐free clonal growth of human muscle satallite cells (HMSC). However, neither inhibits differentiation of HMSC, and when both are added to a minimal serum‐free differentiation medium, they enhance survival and maintenance of human myotubes. A combination of 10 ng/mL EGF and 0.5 mg/mL BSA, added to MCDB 120 plus 10 μg/mL insulin, increasesboth total protein per dish and total creatine kinase activity, and keeps the myotubes in good condition for a longer period of time. The myotubes become cross‐striated and exhibit frequent spontaneous twitching. Substantial amounts of neonatal myosin heavy chain and the MM isozyme of creatine kinase are expressed, together with detectable amounts of adult fast myosin heavy chain. With regular feeding, these cultures can be maintained for at least 3 weeks with no overgrowth by mononucleate cells, and with far less degeneration than with insulin as the only supplement.
McArdle's disease and gout
Authors: Puig Juan G. , de Miguel Eugenio , Mateos Felícitas A. , Miranda Ma Eugenia , Romera Nuria M. , Espinosa Ana , Gijón Juan
Published: January 2005

We report the first case of McArdle's disease (muscle phosphorylase deficiency) and tophaceous gout. To examine the contribution of adenine nucleotide degradation to the disturbance of uric acid metabolism, we labeled the adenine nucleotide pool with [8‐14C]adenine, and measured plasma and urine purines following vigorous exercise tests. Plasma and urinary hypoxanthine and xanthine concentrations and the specific radioactivity of urinary purines increased markedly, but plasma urate levels and uric acid excretion were not substantially modified. We suggest that, in this patient, the association of McArcle's disease with gout is coincidental. © 1992 John Wiley & Sons, Inc.
Effects of reduced joint mobility and training on Na, K‐ATPase and Ca‐ATPase in skeletal muscle
Authors: Leivseth Gunnar , Clausen Torben , Everts Marie E. , Bjordal Erling
Published: January 2005

In guinea pigs, the ankle joint was partly immobilized in a position reducing dorsiflection to 105° (as compared to the normal value of 30°). When compared with the contralateral unrestrained leg, this led to a significant atrophy and a decrease in contractile force (−23%) of the gastrocnemius and plantaris muscle reaching minimum (−19% and −23%) after 3 weeks, but no evidence of degenerative changes. Total contents of Ca and Ca‐ATPase were increased by 27% and 22%, respectively. After 4 to 5 weeks of reduced mobility, the concentration of [3H]ouabain binding sites in gastrocnemius muscle returned to control level. The lowest concentration of [3H]ouabain binding sites reached during reduced mobility was 258 ± 13 pmol/g wet wt., and the maximum value attained following 3 weeks of reduced mobility and 3 weeks of training by running was 498 ± 25 pmol/g wet wt., i.e, 93% higher. In soleus, training produced an increase of 25%. Clinically, it is important to realize that movable braces cannot prevent the development of muscular atrophy. The observed spontaneous recovery of the Na, K‐pump concentration may partly explain why patients using movable casts show a better capacity for physical performance than those treated with complete immobilization. In conclusion, the total concentration of Na, K‐pumps in guinea pig skeletal muscle undergoes downregulation and upregulation as a function of contractile activity as well as muscle length under conditions mimicking the constraints on mobility frequently used in the clinical treatment of lesions. © 1992 John Wiley & Sons, Inc.
Dextrans as markers for endocytosis in innervated and denervated skeletal muscle
Authors: Elmquist Stefan , Libelius Rolf , Lawoko Grace , Tågerud Sven
Published: January 2005

Fluorescence‐labeled dextrans were evaluated as markers for endocytosis in skeletal muscle. Fluorescein isothiocyanate (FITC)‐labeled dextrans (average molecular weight 3900 to 71200) showed a higher uptake in denervated than in innervated muscle both in vitro and in vivo. The in vitro uptake of FITC‐dextran (35.600) increased linearly with time at 37°C, and was almost completely inhibited by low temperature (4°C). The uptake was not a pure bulk uptake, because a saturable component was evident from the concentration dependence and from competition experiments with unlabeled dextran. The uptake of FITC‐labeled or rhodamine B isothiocyanate (RITC)‐labeled dextrans in denervated muscle occurred mainly in small segments of the fibers centered around the denervated endplate region. However, not all denervated fibers showed such segments. Periodic acid Schiff's base staining for carbohydrates stained dextrans in denervated muscle fibers. Some staining, probably of lysosomes, was also observed in denervated muscle not exposed to dextran. © 1992 John Wiley & Sons, Inc.
Vasculitic neuropathy in a patient with cryoglobulinemia and anti‐MAG IGM monoclonal gammopathy
Authors: Thomas Florian P. , Lovelace Robert E. , Ding Xin‐Sheng , Sadiq Saud A. , Petty George W. , Sherman William H. , Latov Norman , Hays Arthur P.
Published: January 2005

A patient with sensorimotor mononeuritis multiplex had a type II cryoglobulin with an IgM kappa M‐protein that appeared to contain monoclonal anti‐MAG antibodies of the same isotype. A sural nerve biopsy demonstrated necrotizing arteritis and features of both axonal degeneration and demyelination. IgM kappa and C3 deposits were present on the myelin sheath of some residual nerve fibers. The findings suggest that the anti‐MAG antibodies contributed to the myelin damage, while cryoprecipitates may have caused the vasculitis and axonal degeneration. © 1992 John Wiley & Sons, Inc.
The relative diagnostic sensitivity of different F‐wave parameters in various polyneuropathies
Authors: Fraser Jeffrey L. , Olney Richard K.
Published: January 2005

We studied F‐wave minimum latency, persistence, and chronodispersion in the median and ulnar nerves of 70 controls and 75 patients with various polyneuropathies. Prolonged minimum latency was the most frequent F‐wave abnormality in all groups of patients with polyneuropathy. The finding of decreased persistence or absence of F‐responses was comparable in sensitivity to prolonged minimum latency in Guillain–Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP), whereas chronodispersion had a comparable sensitivity only in CIDP. Decreased persistence of obtained F‐responses, and the absence of F‐responses in nerves with low compound muscle action potential amplitudes, were nonspecific findings. F‐wave studies often provide useful additional information in the evaluation of patients suspected of having a polyneuropathy. In patients with axonal polyneuropathies, we found that F‐wave studies are significantly more sensitive than standard motor conduction studies in identifying physiological abnormalities of motor axons. Furthermore, in a patient with an acquired polyneuropathy, the finding of markedly prolonged minimum latency, or the absence of F‐responses in nerves with normal CMAP amplitude, is highly specific for the presence of demyelination. © 1992 John Wiley & Sons, Inc.
Development of calcitonin‐gene‐related peptide, chromogranin a, and synaptic vesicle markers in rat motor endplates, studied using immunofluorescence and confocal laser scanning
Authors: Li Jia‐Yi , Dahlström Annica B.
Published: January 2005

The presence of calcitonin‐gene‐related peptide (CGRP) and chromogranin A was investigated in the developing rat (E18–adult) motor system, using immunofluorescene and confocal laser scanning, and compared with synaptic vesicle markers, synaptophysin and synapsin I. In lumbar motor perikarya CGRP‐Ll and Chr A‐Ll were present in high intensities in E18 and P1 perikarya in the anterior horn. With increasing age immunoreactivity decreased. Chr A‐Ll was sparse in the adult. In peroneal endplates, p38‐Ll and SYN l‐Ll were present in all stages, including E18. Peptide‐Ll was very weak or absent in early stages (E18 and P1), but abundant in P8 and P18, especially CGRP‐LI, and decreased again in P32 and adult animals. These observations indicate that the peptides have precise functions during certain developmental stages, possibly related to synapse maturation, receptor concentration, and reduction of supernumerary endplates. Both peptides are rapidly transported anterogradely in adult motor axons, and may serve physiological functions also in the adult. © 1992 John Wiley & Sons, Inc.
Short segment incremental studies in the evaluation of ulnar neuropathy at the elbow
Authors: Campbell William W. , Pridgeon Rhonda M. , Sahni K. Singh
Published: January 2005

Conventional electrodiagnosis may localize an ulnar neuropathy to the general region of the elbow. Separating retroepicondylar compression from compression by the humeroulnar aponeurotic arcade from compression by the deep flexorpronator aponeurosis is more difficult. In 35 patients, we compared localization by conventional inching (stimulating stepwise around the elbow searching for focal conduction block or differential slowing) to localization by a more quantitative short segment incremental stimulation (SSIS) technique assessing latency change over consecutive 1 cm segments. Results of percutaneous studies were compared with findings of intraoperative electroneurography. We conclude that SSIS identifies compression levels more accurately than standard inching, and that SSIS and intraoperative electroneurography correlate highly, but not perfectly. Studies confined to a search for conduction block or differential slowing are limited by the low incidence of conduction block in chronic compression neuropathies. © 1992 John Wiley & Sons, Inc.
Mild ischemia causes severe pathological changes in experimental diabetic nerve
Authors: Nukada Hitoshi
Published: January 2005

Nerve ischemia is considered one of etiological factors in the development of structural changes in peripheral nerves associated with diabetes mellitus. To assess the effect of mild ischemia on diabetic nerve, a subthreshold dose of polystyrene microspheres was indected intraarterially to occlude microvessels of the sciatic nerve and its branches in 20‐week streptozotccin‐induced diabetic and control rats. Diabetic sciatic and tibial nerves showed severe pathological change of myelinated fibers, whereas nondiabetic nerves were normal or had minor structural abnormalities. Morphometrical evaluation confirmed a greater frequency of abnormal myelinated fibers in diabetic nerves especially in central fascicular regions. The result indicate that diabetic nerve has an increased morphological susceptibility to nerve ischemia. Endoneurial hypoxia, which may result from hemorheological and vascular abnormalities, is likely to cause a lowered threshold to ischemic tolerance in diabetic nerve. This increased vulnerability to ischemia may render diabetic nerve unduly susceptible to hyperglycemia‐induced systemic tissue abnormalities. © 1992 John Wiley & Sons, Inc.
Neuromuscular responses of patients with multiple sclerosis
Authors: Rice Charles L. , Vollmer Timothy L. , Bigland‐Ritchie Brenda
Published: January 2005

Muscle weakness, studied in 4 patients with multiple sclerosis (MS), was compared with values from normal subjects. Twitch occlusion showed that normal subjects could activate their muscles maximally, but patients rarely achieved >60% activation. In both groups, motoneuron firing rates increased linearly with force. Consistent with the reduced level of activation, MCV firing rates in MS muscles rarely exceeded 17 Hz (compared with ∼24 Hz for normals). However, for right and left muscles of one patient, mean maximum firing rates were 14.2 ± 2 Hz and 8.0 ± 2 Hz, but her muscles could be activated to levels >92% and 60%, respectively. This patient's ability to achieve higher than expected forces at low firing rates was probably due to her slow muscle contractile speeds, especially ½‐relaxation time (75 to 115 ms, cf. ∼60 ms for normals), and high twitch/tetanus ratio (0.4, cf. 0.2). © 1992 John Wiley & Sons, Inc.
F waves and motor unit size
Authors: Dengler Reinhard , Kossev Andon , Wohlfahrt Kai , Schubert Margot , Elek Josef , Wolf Werner
Published: January 2005

M responses and twitch contractions were evoked in single motor units (MUs) of the first dorsal interosseus muscle by intramuscular microstimulation of motor axons. Two‐hundred nine MUs were studied in 21 subjects. Thirty‐five MUs (17%) showed F waves in addition to M responses. Twitch force was used to provide an indirect measure of MU size; additionally, twitch contraction time was measured. There was no select group of MUs generating F waves with regard to the above contraction parameters. However, four of five MUs with very high twitch forces, above 70 mN, generated F waves. We conclude that MUs of all sizes produce F waves with similar probability. Only few MUs with very strong twitch forces, i.e., very large MUs, may be more subject to F‐wave production and may be involved in the generation of the so‐called repeater F waves. © 1992 John Wiley & Sons, Inc.
The pterygoid reflex in man and its clinical application
Authors: Hopf H. C. , Ellrich J. , Hundemer H.
Published: January 2005

A technique for eliciting and recording the stretch reflex (R) of the medial pterygoid muscle (Pter) is described. The latency was 6.9 ± 0.43 ms in 23 healthy volunteers (mean age 23.7 years) showing a side‐to‐side difference of 0.29 ± 0.21 ms. The PterR latencies were little shorter and side‐to‐side difference little greater than of the masseter reflex. Observations in 5 selected patients with small brainstem lesions suggest that the neurons of the PterR afferents form a cluster within the caudal portion of the trigeminal mesencephalic nucleus. Testing the masseter and pterygoid reflexes provides a more precise localization of small ponto‐mesencephalic lesions. © 1992 John Wiley & Sons, Inc.
Lambert–Eaton syndrome: Antigen–antibody interaction and calcium current inhibition in chromaffin cells
Authors: Viglione Michael P. , Creutz Carl E. , Kim Yong I.
Published: January 2005

Plasma and IgG obtained from 10 Lambert–Eaton myasthenic syndrome (LES) patients (5 with carcinoma, 5 without associated cancer), 6 healthy subjects, and 1 patient with small‐cell lung cancer (SCLC) were examined in their ability to recognize chromaffin cell antigens on Western blots. The pattern of antigen recognition was compared with the magnitude of inhibition of voltage‐dependent calcium and sodium currents recorded with the patch‐clamp technique from chromaffin cells. Eight of the 11 patients with LES and/or SCLC recognized plasma membrane proteins and 9 of the patients' IgG interacted with cytoplasmic antigens with no apparent pattern of antigen recognition between patients. Also, there was no obvious band pattern distinguishing patients with LES from those with LES and concurrent SCLC. Eighty percent of the LES patients' antibodies were capable of reducing the calcium current (ICa) in chromaffin cells. One of the novel findings of this study is that 30% of the patients had produced antibodies which were able to inhibit both calcium and sodium currents (INa). The heterogeneous response of the IgG on the Western blots does not appear to correlate with the efficacy of reducing the inward currents. © 1992 John Wiley & Sons, Inc.
Gangliosides attenuate vincristine neurotoxicity on dorsal root ganglion cells
Authors: Houi Kouji , Mochio Soichiro , Kobayashi Takaaki
Published: January 2005

We investigated the effects of bovine brain gangliosides on the neurotoxicity of vincristine in dissociated cultures of dorsal root ganglion cells from 10‐day chick embryos. The effects of the drugs were quantified as the numbers of neurite‐bearing cells or total neurite length in individual neurite‐bearing cells. The administration of vincristine (1 to 1000 pg/mL) inhibited neurite outgrowth from the cells, whereas gangliosides (10 to 1000 m̈g/mL) protected them against this inhibition in a concentration‐dependent manner. Electron microscopy revealed vincristine‐induced fragmentation and longitudinal disorientation of microtubules in neurites and showed the protection by gangliosides against such damaging effects. Our results show that exogenous administration of gangliosides attenuates the neurotoxicity of vincristine in vitro. © 1993 John Wiley & Sons, Inc.
Needle electromyography of the diaphragm: A new technique
Authors: Saadeh Peter B. , Crisafulli Christine Fitzpatrick , Sosner Julian , Wolf Edna
Published: January 2005

Electrodiagnostic evaluation of diaphragmatic function has consisted of phrenic nerve stimulation and surface or esophageal recordings of the electrical activity of the diaphragm. Needle electromyography of the diaphragm has rarely been reported because of the perceived danger of this procedure. We describe a new technique for needle electromyography of the diaphragm. Am EMG electrode is placed in the costal insertion of the diaphragm under the 8th, 9th, or 10th rib cartilage, distant from the major vessels, pleura, lungs, and abdominal viscera. Diaphragmatic denervation was found in 42 of 81 patients using this method. There were no complications related to the procedure. Needle electromyography of the diaphragm provides important information in the diagnosis and management of respiratory dysfunction. © 1993 John Wiley & Sons, Inc.
Peripheral nerve lesions in HTLV‐I associated myelopathy (HAM/TSP)
Authors: Bhigjee Ahmed I. , Bill Pierre L. A. , Wiley Clayton A. , Windsor Isobel M. , Matthias Denise A. , Amenomori Tatsuhiko , Wachsman William , Moorhouse David
Published: January 2005

Peripheral nerve dysfunction (PND) was found in as many as 43% of our patients with human T‐cell lymphotropic virus type I (HTLV‐I)–associated myelopathy (HAM/TSP). To evaluate the PND further we biopsied the sural nerve in 6 patients. The histological features were varying degrees of demyelination, remyelination, axonal atrophy and degeneration, and perineurial fibrosis. “Globule” or “sausage” formation was prominent in two of the specimens. Inflammatory infiltrates were absent. No deposits of IgG, IgM, IgA, or complement were detected in the biopsies. No viral antigen or proviral DNA was detected. It is proposed that the PND and the histological findings noted are part of HTLV‐I–associated disease and not an unrelated disorder. The pathogenesis of the PND remains unclear. There was no evidence of direct viral infection. The histological findings could represent primary changes induced by viral‐triggered release of soluble factors, such as cytokines or secondary changes to more proximal disease, e.g., root involvement. © 1993 John Wiley & Sons, Inc.
Distinguishing unloading. Versus reloading‐induced changes in rat soleus muscle
Authors: Krippendorf Beth B. , Riley Danny A.
Published: January 2005

Previously, solei from rats orbited 12.5 days aboard Cosmos 1887 biosatellite were biopsied 48–56 hours postflight. These atrophic muscles showed severe pathology. Designing a ground‐based model of that space flight, we tested the hypothesis that 48 hours of postflight muscle reloading induced pathological changes. Rats were subjected to 12.5 days of hindlimb suspension unloading and biopsied immediately after suspension or after returning to normal weightbearing 12, 24, or 48 hours. Soleus morphological changes were quantitated on histochemically and immunohistochemically stained cross‐sections. Solei from 0‐hour reloaded rats showed significantly decreased wet weights, diminished myofiber cross‐sectional area, angular myofibers, myofiberil disruption, and more myofibers expressing fast myosin. Compared with suspension alone (0‐hour reloading), reloading 12–48 hours induced slightly increased soleus wet weights, myofiber swelling, significant interstital tissue edema, macrophage activation, and monocyte infiltration. These results suggest the degree and type of muscle degenerative changes observed postflight depend on the duration of gravity readaptation before biopsy and not solely on exposure to microgravity. © 1993 John Wiley & Sons, Inc.
Sixteenth annual AAEM Edward H. Lambert lecture. Electrodiagnostic aspects of diabetic neuropathies: Entrapments
Authors: Johnson Ernest W.
Published: January 2005

A MEDLINE review suggested a lack of recent studies about the entrapments seen with underlying diabetic neuropathy. Suggested protocols for research in diabetic peripheral neuropathy have not included the concepts of entrapments as an early — indeed, first manifestation of the neuropathy. Carpal tunnel syndrome is a frequent accompaniment of diabetic peripheral neuropathy. Assessment of the degree of entrapment superimposed on the generalized peripheral neuropathy can be clarified by analysis of the CMAP and the SNAP — particularly with respect to duration of the negative spike of the action potential. Also, analysis of the action potentials elicited by stimulation of the ulnar and radial nerves and their comparison with the median nerve is often helpful. Finally careful inspection of the actions potential when stimulating proximal and distal to the entrapment will establish the degree of nerve compromise relative to the underlying diabetic neuropathy.
Involvement of peripheral sensory fibers in amyotrophic lateral sclerosis: Electro‐physiological study of 64 cases
Authors: Mondelli Mauro , Rossi Alessandro , Passero Stefano , Guazzi Gian Carlo
Published: January 2005

We report electrophysiological findings of conduction along peripheral sensory fibers in 64 patients with amyotrophic lateral sclerosis. Distribution of the values of action potential amplitudes and conduction velocities of peripheral afferent fibers were significantly lower than in normal age‐matched controls. Sensory action potential amplitudes (SAPas) were more affected than sensory conduction velocities (SCVs). When single patients were considered, SAPas were slightly but significantly reduced in 22% of the cases (median nerve 17%, ulnar nerve 11%, and sural nerve 22%). A parallel decrease in SCVs and MCVs in 14 patients in whom the study was repeated over a period of time was also found. All these electrophysiological findings are due to progressive neuronopathy of peripheral sensory fibers. A pathogenetic mechanism is proposed. © 1993 John Wiley & Sons, Inc.
Sustained focal effects of low‐dose intramuscular succinylcholine
Authors: Walker Francis O. , Scott Gregory E. , Butterworth John
Published: January 2005

We studied low‐dose intramuscular succinylcholine in 9 subjects as part as an ongoing investigation of its potential to predict responses to botulinum toxin. We measured compound muscle action potentials (CMAPs) from the extensor digitorum brevis (EDB) muscles in each foot before and after intramuscular injections of 2.5 mg of succinylcholine into the EDB. Succinylcholine reduced mean CMAP amplitudes to 42% of baseline; the maximal reduction occurred at 19 ± 6 (mean standard deviation) minutes. Recovery to 73% of the baseline CMAP amplitude (approximately 50% recovery from block) occurred at 105 ± 49 minutes after injection. Repetitive (train‐of‐four) stimulation at 2 Hz produced mild CMAP decrements (5–25%), but only during the recovery phase. Varying the succinylcholine concentrations (10, 20, or 50 mg/mL) while holding the total drug dose constant did not change the rate of onset or the extent of block. No systemic complications occurred. We conclude that: (1) 2.5 mg intramuscular succinylcholine can safely induce selective muscle weakness with a time course that differs from intravenously administered succinylcholine; and (2) further clinical studies comparing intramuscular succinylcholine and botulinum toxin are warranted. © 1993 John Wiley & Sons, Inc.
Far‐field potentials
Authors: Dumitru Daniel , Jewett Don L.
Published: January 2005

Far‐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

An 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

To 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

Local 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

The 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.