bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in the pathogenesis of diabetic neuropathy. Clues from human diabetic neuropathy
Authors: Low Phillip A.
Published: January 2005

Recent advances in the understanding of the pathogenesis of diabetic neuropathy have been made in six areas. (1) There is support for the notion that a reduction in nerve free myoinositol may be responsible in part for the nerve conduction slowing in diabetic neuropathy. (2) There is further evidence of microvascular abnormalities, including morphometric evidence of multifocal fiber loss and of capillary changes in biopsied sural nerve. (3) There is evidence of endoneurial hypoxia, including the findings of reduced nerve blood flow and endoneurial oxygen tensions in chronic experimental diabetic neuropathy (EDN). (4) The major mechanisms of resistance to ischemic conduction failure (RICF) is the marked increase in nerve energy substrates. (5) Recent studies provide certain insights into clinical characteristics of human diabetic neuropathy (HDN), including the assymetric pattern of HDN, the paradox between liability to pressure palsies and RICF, and insulin‐related acute painful neuropathy. (6) The suggested pathogenetic scheme incorporates the notion that once hypoxia is established, it may start a vicious cycle of further capillary damage and escalating hypoxia.
Primary segmental demyelination in the sural nerve in cockayne's syndrome
Authors: Ohnishi Akio , Mitsudome Akihisa , Murai Yoshiyuki
Published: January 2005

In a typical case of Cockayne's syndrome, morphometric histopathologic findings of the sural nerve were described and compared with data on two controls. The main pathologic changes of myelinated fibers were segmental demyelination and remyelination with onion bulb formation and a moderate decrease of myelinated fibers. There was no evidence of axonal atrophy in relation to myelin spiral length. In addition, no evidence of the clustered occurrence of demyelinated and remyelinated internodes was obtained on the statistical evaluation of the distribution of such internodes. Although the presence or absence of hypomyelination of a mild degree and maldevelopment of axons to be myelinated has not been clarified, our morphometric data do suggest the presence of primary segmental demyelination of the biopsied sural nerve.
A critical review of therapies in acute and chronic inflammatory demyelinating polyneuropathies
Authors: Pollard J. D.
Published: January 2005

Acute and chronic inflammatory demyelinating neuropathies are among the most common treatable neuropathies seen by neurologists. Evidence for effective therapy has only recently been provided by randomized or controlled trials. In the Guillain‐Barré syndrome such evidence does not support the use of corticosteroids or immunosuppressive agents. However, when used early in the course, plasma exchange (PE) has been shown to lessen the severity and shorten the duration of the disease; it is indicated only in severely paralyzed patients or those whose rapid deterioration suggests the imminent need for ventilatory support.

Some patients with chronic inflammatory demyelinating polyneuropathy (CIDP) respond to corticosteroid therapy or other immunosuppressive agents. PE is also effective in certain patients, but there is no sound evidence to data concerning combined immunosuppression and PE. The rationale of PE in these conditions and whether it is the removal of a toxic factor or the replacement fluid used that is beneficial remains to be clarified.
Ischemic exercise test: Failure to detect partial expression of Mcardle's disease
Authors: Taylor Robert G. , Lieberman James S. , Portwood Margaret M.
Published: January 2005

The forearm ischemic exercise test (FIET) is a very important clinical tool for evaluation of patients suspected to have a metabolic disorder of muscle function. Failure to elevate lactate in blood washed out from ischemically exercised muscles confirms an abnormality of glycolytic metabolism. A normal increase of lactate on FIET is assumed to rule out a disorder of glycolytic metabolism. Two patients with low levels of muscle phosphorylase are presented who produced a normal elevation of lactate on FIET. This suggests that, although the FIET is capable of identifying patients with absence of myophosphorylase, the test cannot identify patients with a partial expression of that disorder. Evaluation of the blood samples for ammonia in addition to lactate can be a significant help in confirming that the exercise performed by the patient was an adequate challenge for the glycolytic pathway. In addition, failure to elevate ammonia on ischemic exercise can identify a relatively new disorder of muscle metabolism.
Distant effects of local injection of botulinum toxin
Authors: Lange Dale J. , Brin Mitchell F. , Warner Carolyn L. , Fahn Stanley , Lovelace Robert E.
Published: January 2005

We studied five patients who received local injections of botulinum toxin for dystonic disorders to determine if there had been any distant effect on neuromuscular transmission. No patient developed weakness or abnormalities on routine electrophysiologic testing. In all patients who received more than 245 U of toxin, SFEMG in the extensor digitorum communis muscle, a muscle distant to all those injected, was abnormal. Fiber density was increased in the two patients who received the largest cumulative dose. Jitter was maximally increased at slow firing rates, confirming its presynaptic basis. Our results reveal that there is an effect on neuromuscular transmission in muscles distant to those injected with botulinum toxin for dystonia.
AAEE minimonograph #27: Differential diagnosis of myotonic syndromes
Authors: Streib Erich W.
Published: January 2005

Recent advances in neuromuscular diseases have also widened the diagnostic spectrum of myotonic disorders. Treatment, prognosis, and genetic aspects are different in the various syndromes and mandate a correct diagnosis. The combination of neurologic examination, standard EMG, exercise test, cold exposure, potassium loading, eye examination, and pedigree analysis allows correct classification of nearly all patients with myotonic disorders. In this review emphasis is placed on clinical features and electrophysiologic evaluation.
Conduction block in hereditary neuropathy with susceptibility to pressure palsies
Authors: Sellman Michael S. , Mayer Richard F.
Published: January 2005

Slow nerve conduction velocities, temporal dispersion of action potentials and conduction block occur in polyneuropathies with segmental demyelination. Conduction block has been reported in focal compressive neuropathies and in acute and chronic autoimmune polyneuropathy but not in hereditary motor and sensory demyelinating neuropathy. We report conduction block in five nerves of four patients from two families with a hereditary neuropathy with susceptibility to pressure palsies and pathologic changes of segmental demyelination and tomaculous swellings. Conduction block that may be long lasting is a feature of this type of hereditary neuropathy, which should be considered in the differential diagnosis of this electrophysiologic finding.
Interactions of vitamin E and penicillamine in the treatment of hereditary avian muscular dystrophy
Authors: Serafin William E. , Dement Samuel H. , Brandon Suzanne , Hill Edward J. , Park Charles R. , Park Jane H.
Published: January 2005

Our prior work demonstrated that penicillamine treatment of dystrophic chickens delayed the onset of symptoms, partially alleviated contractures, improved muscle function, and lowered serum creatine kinase. Penicillamine, a sulfhydryl compound with reducing properties, also prevented inactivation of glycolytic enzymes by protecting thiol groups. The present study shows that vitamin E enhances the therapeutic effects of penicillamine. Interaction of these two reductants is dose related. With vitamin E as adjunct therapy, the dosage level of penicillamine could be lowered by 50%, thereby minimizing side effects. The therapeutic rationale for two antioxidants is that penicillamine may act primarily in the cytoplasm to prevent oxidative damage, whereas the more hydrophobic vitamin E may protect membrane bilayers. Additionally, penicillamine may prevent collagen cross7hyphen;linking and, deposition of insoluble collagen in muscle and thus decrease contracture formation. General applications of combined penicillamine and vitamin E therapy are discussed regarding prevention of free radical and oxidative damage in Duchenne dystrophy and a wide range of human diseases.
Nature and properties of cytotoxic plasma activity in amyotrophic lateral sclerosis
Authors: Ronnevi Lars‐Olof , Conradi Sebastian , Karlsson Evert , Sindhupak Ratana
Published: January 2005

Cytotoxic activity of plasma towards normal red blood cells in patients with amyotrophic lateral sclerosis (ALS) has been studied as a function of progressive plasma dilution and compared with plasma from patients with Charcot–Marie–Tooth's disease (CMT). At progressive dilution the hemolysis by ALS‐plasma showed a specific pattern that differed qualitatively and quantitatively from that of normal plasma as well as CMT and persisted up to a dilution of 1:6561. Differences in dilution pattern were found when comparing different clinical types of ALS. There was evidence for a partial complement dependancy of the reaction that brings about the hemolysis provoked by ALS plasma. Experiments with plasma fractionated by gel filtration and with isolated immunoglobulins produced evidence for cytotoxic properties of IgA and IgG from ALS plasma. The observations speak in favor of a consistency between the observations of plasma cytotoxicity in ALS and earlier observations on immunological abnormalities in the disease.
Two types of mitochondrial crystals in diseased human skeletal muscle fibers
Authors: Farrants George W. , Fil Sven Hovmöller , Stadhouders Ad. M.
Published: January 2005

Mitochondrial crystalline inclusions, frequently found in mitochondrial myopathies, were analyzed by crystallographic techniques and computer‐aided image processing. It could be shown that these structures were real crystals. There are two distinct types of crystal, which can be distinguished by shape, size, and pattern. So‐called type I crystals are usually present in the intracristal space, whereas the type II crystals are preferentially located in the intermembrane space between outer and inner mitochondrial membranes. The unit cell dimensions were found to be 38 × 34 × 8 nm for the type I crystals and 20 × 17 × 8 nm for the type II crystals. These results strongly suggest that the crystals are composed of macromolecules, presumably proteins. Arguments are presented that indicate that type I crystals occur only in type 1 muscle fibers and type II crystals in type 2 muscle fibers.
Real‐time ultrasound imaging of muscles
Authors: Heckmatt J. Z. , Pier N. , Dubowitz V.
Published: January 2005

A prospective study was done on 222 consectutive new patients referred to our pediatric muscle clinic to assess the diagnostic value of ultrasound imaging. Ultrasound scans were interpreted without knowledge of clinical presentation or results of other tests. Muscular dystrophy produced a brightly speckled pattern of increased echo from the muscle, whereas spinal muscular atrophy showed a moderate increase in muscle echo and associated muscle atrophy. Acute dermatomyositis produced a moderate increase in echo that varied markedly with the direction of the ultrasound beam in relation to the muscle fibres. The ultrasound scan was normal in children with hypotonia of cerebral origin, Prader Willi syndrome, ligamentous laxity, and other “nonneuromuscular” causes. In eight patients ultrasound scanning showed a striking degree of selective involvement of individual components of the quadriceps muscle, which provided considerable diagnostic help for selective needle biopsy. Ultrasound scanning in children has the major advantage of being a nonivasive and pleasant out‐patient procedure, which can be readily done on multiple sites. It is a valuable screening test in the investigation of children with neuromuscular disorders.
Multifocal acquired demyelinating neuropathy masqurading as motor neuron disease
Authors: Parry Gareth J. , Clarke Stephen
Published: January 2005

We report five patients with pure motor neuropathy characterized by multifocal weakness, muscle atrophy that was sometimes profound, cramps, and fasciculations with relatively preserved reflexes. The clinical picture led to an initial diagnosis of motor neuron disease in all cases, but nerve conduction studies revealed multifocal conduction block confined to motor axons and predominantly involving proximal nerve segments. Routine sensory nerve conduction studies, ascending compound nerve action potentials, and somatosensory evoked potentials were all normal even through nerve segments in which motor conduction was severely blocked. Onset of symptoms was insidious, and progression was indolent. In two cases, after many years of neuropathy, sensory abnormalities developed but remained clinically trivial. These unusual cases probably have the same pathogenesis as previously described patients with persistent multifocal conduction block. Distinction from motor neuron disease is critical, since chronic demyelinating neuropathy may respond to treatment.
Axonal conduction velocity and force of single human motor units
Authors: Dengler Reinhard , Stein Richard B. , Thomas Christine K.
Published: January 2005

Tungsten microelectrodes of the type used for microneurography have been used to record motor units selectively from the first dorsal interosseous and abductor pollicis brevis muscles of normal subjects and patients who had had complete sections of the ulnar or median nerve. After determining the recruitment threshold and the twitch tension (spike‐triggered averaging) of a single unit, its nerve was stimulated at the wrist and the elbow using surface electrodes. By adjusting the position of the surface electrode and the stimulus intensity and by using computerized subtraction of responses just above and below threshold for a given unit, the same motor unit could often be identified in response to stimulation at both sites and its conduction velocity determined. The twitch tension and recruitment threshold of the motor units were closely correlated with the conduction velocity of the motor axons in normal subjects. Preliminary data from patients suggests that this method should be applicable to patients with a number of neuromuscular disorders.
Entrapment neuropathy of the ulnar nerve at its point of exit from the flexor carpi ulnaris muscle
Authors: Campbell William W. , Pridgeon Rhonda M. , Sahni Singh K.
Published: January 2005

The ulnar nerve normally enters the flexor carpi ulnaris (FCU) proximally and anteriorly between the humeral and ulnar heads of the muscle. After an intramuscular course of several centimeters, the nerve exits the FCU distally to lie in a tissue plane between the FCU and the flexor digitorum profunds (FDP). A patient with ulnar neuropathy studied by intraoperative electroneruography demonstrated major focal conduction block at the point where the nerve exited the FCU. A fivefold increase in amplitude and reversal of a dispersed, irregular compound muscle action potential to a more normal configuration occurred with stimulation just distal to the point of exit. There was no evidence by inspection, probing, or electroneurography of compression in the retrocondylar groove or at the cubital tunnel. In a series of 100 cadaver dissections, the intermuscular septum between FCU and FDP was thick and tough in several specimens. This septum may represent a site of ulnar nerve entrapment.
Peripheral neuropathy in late onset spinocerebellar ataxia
Authors: Nousiainen Unto , Partanen Juhani , Laulumaa Veikko , Paljäurvi Leo
Published: January 2005

We studied 10 patients with late onset spinocerebellar ataxia including electrophysiological and muscle biopsy examinations. Nerve conduction studies of eight patients revealed axonal neuropathy, and six cases also showed signs of the involvement of the lower motor neuron. In 9 patients quantitative analysis of single motor unit potentials (MUPs) of the tibialis anterior or biceps brachii muscles showed mild to severe neuropathic changes and in all 10 patients the histopathological examination of the tibialis anterior showed mild to severe neuropathic changes. Neither nerve conduction studies, quantitative MUP analysis, nor histological findings of the muscle were related to the severity or duration of the disease.
Somatosensory evoked potentials: Lack of value for diagnosis of thoracic outlet syndrome
Authors: Veilleux Martin , Stevens J. Clarke , Campbell J. Keith
Published: January 2005

Twenty patients with thoracic outlet syndrome (TOS) seen at the Mayo Clinic between October 1984 and November 1985 were studied prospectively with routine nerve conduction studies, concentric needle examination, and bilateral median and ulnar somatosensory evoked potentials (SEPs). Results of nerve conduction studies and needle examination were abnormal in 30% of the patients, one patient having a reduced ulnar sensory nerve action potential amplitude and five others having neurogenic motor unit potential changes in the hand muscles. Ulnar SEPs were abnormal in three patients (15%), and median SEPs were abnormal in one patient, who also had abnormalities in ulnar SEPs. In patients with TOS, routine nerve conduction studies and needle examination were the most helpful electrophysiologic studies in excluding more common conditions. The routine use of ulnar SEPs in the evaluation of patients with TOS is probably not worth‐while.
Resistance to ischemic conduction block of the peripheral nerve in hyperglycemic rats: An electrophysiological study
Authors: Shirabe Susumu , Kinoshita Ikuo , Matsuo Hidenori , Takashima Hidetoshi , Nakamura Tatsufumi , Tsujihata Mitsuhiro , Nagataki Shigenobu
Published: January 2005

Resistance to ischemic conduction block (RICB) was studied in rats with streptozotocin (STZ) induced hyperglycemia, hyperglycemia by glucose injection, and glycerin‐induced hyperosmolarity. Ischemia was produced by tight ligation at the base of the tail. The time required for nerve action potentials (NAP) to disappear was defined as the disappearance time of NAP (DT‐NAP). Both STZ and glucose rats showed a marked prolongation of DT‐NAP at 2 hours after injection of STZ (up to 120 minutes) or glucose (up to 95 minutes), as compared with the control rats (less than 45 minutes). Hyperosmolar rats showed no prolongation of DT‐NAP. The amplitude of NAP remained at the initial level for at least 2 hours after ligation of the sciatic nerve, whereas NAP disappeared within 45 minutes after ligation of the abdominal aorta. These findings indicate that the RICB can be produced by means of hyperglycemia without the presence of diabetic neuropathy and is the most sensitive indicator of hyperglycemia.
Muscle action potential propagation velocity changes during activity
Authors: Juel Carsten
Published: January 2005

Fatigue from high frequency stimulation is associated with EMG signal changes, which are primarily due to a slowing of the sarcolemma conduction velocity. In the present study, in which isolated mouse soleus and extensor digitorum longus muscles have been studied, it is shown that the action potential propagation velocity is (1) decreased by an increased extracellular potassium concentration, (2) independent of extracellular pH, (3) decreased by low intracellular pH, and (4) nearly independent of moderate changes in the sodium gradient. The EDL muscle is more affected than the soleus muscle. The ion effects on propagation velocity are seen within the physiological ranges. The propagation velocity was decreased after 2 min of electrical stimulation and recovered with a time course similar to the pH recovery. The effects of extracellular potassium and internal pH are due to independent mechanisms.
Role of glucocorticoids in increased muscle glutamine production in starvation
Authors: Tischler Marc E. , Henriksen Erik J. , Cook Paul H.
Published: January 2005

The influence of glucocorticoids on muscle glutamine production in starvation was studied by using cortisol‐treated or non‐cortisol‐treated, starved, adrenalectomized rats. Administration of cortisol at physiological doses in vivo (1 mg/100 g body weight) to fasted, adrenalectomized rats increased the muscle ratio of glutamine/glutamate and the activity of glutamine synthetase after only 6 hours. Prior treatment of fasted, adrenalectomized animals with actinomycin D or proglavine abolished these increases by cortisol. Therefore, cortisol induces muscle glutamine synthetase, and this induction can be detected by changes in the fresh‐muscle ratio of glutamine/glutamate. Using this ratio as a qualitative indicator of muscle glutamine synthesis, the role of glucocorticoids in modifying muscle glutamine production in starvation was studied. In fresh‐frozen soleus, extensor digitorum longus, and diaphragm muscle, starvation led to greater ratios of glutamine/glutamate and higher levels of tyrosine, which are indicative of enhanced muscle protein turnover. These effects were not apparent in starved, adrenalectomized animals but were restored, at least partially, by administering a physiological dose of cortisol. Therefore, glucocorticoids seem essential for promoting muscle glutamine production in starvation probably by inducing the activity of glutamine synthetase.
AAEE minimonograph #29: Automatic quantitative electromyography
Authors: Dorfman Leslie J. , McGill Kevin C.
Published: January 2005

The present status of different computerized methods of automatic quantitative electromyography are reviewed. Interference pattern methods–turns analysis, spectral analysis–are efficient, but the results usually cannot be directly related to the physiological properties of the motor units. Integration analysis does not currently have a major role in diagnostic electromyography. Traditional measurement of single motor unit action potentials during weak contraction can be facilitated and made more objective with computer assistance, but only the lowest‐threshold motor units in the muscle are amenable to study. A new class of methodologies under development permit the decomposition of interference patterns into their constituent motor unit action potentials for measurement of configurational and behavioral properites. Patient data from these various methods can be statistically compared with normative data bases available on‐line in computerized electromyographs. Both qualitative and quantitative electromyography have applications in the neuromuscular electrodiagnostic examination.
AAEE case report #15: Ulnar neuropathy at or distal to the wrist
Authors: Olney Richard K. , Hanson Maurice
Published: January 2005

A 56‐year‐old woman developed insidiously progressive, painless weakness of her left hand. Clinical and electrodiagnostic abnormalities were limited to the motor function of the hand, with the hypothenar less affected than more distal ulnar muscles. Compression of the distal ulnar nerve by a ganglionic cyst was surgically relieved and there was postoperative improvement. The electrodiagnosis of ulnar neuropathy at or distal to the wrist is reviewed together with relevant anatomic and clinical aspects of these uncommon lesions.
Physiologic and anatomic basis for contralateral R1 in blink reflex
Authors: Soliven Betty , Meer Jacob , Uncini Antonino , Petajan Jack , Lovelace Robert
Published: January 2005

We studied the rate of appearance and mechanism of contralateral R1 responses in normal subjects. Contralateral R1 could be produced by facilitating maneuvers such as a gentle contraction of the orbicularis oculi and conditioning stimulus of the median nerve. In addition, changing the position of the stimulating anode to the midline evoked these responses that were abolished by blocking the contralateral supraorbital nerve, confirming its peperipheral origin. We conclude that crossed trigeminofacial pathways probably exist in normal subjects, but in some instances contralateral peripheral trigeminal ophthalmic sensory fibers may be stimulated, giving rise to a contralateral R1 response.
The spectrum of peripheral neuropathy associated with ARC and AIDS
Authors: Miller Robert G. , Parry Gareth J. , Pfaeffl Wolfgang , Lang William , Lippert Randolph , Kiprov Dobri
Published: January 2005

Peripheral neuropathy is increasingly recognized as a complication of the Aquired Immune Deficiency Syndrome (AIDS) and AIDS‐related complex (ARC), but the varied clinical features have been incompletely described. Thirty homosexual men with peripheral neuropathy were evaluated in this study. Twenty‐one had ARC and nine had AIDS. Four distinct clinical syndromes were recognized: distal sensorimotor polyneuropathy, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), mononeuropathy multiplex, and progressive polyradiculopathy. Four patients with clinical, electrophysiologic, and histologic evidence of CIDP and severe progressive weakness improved with plasma exchange, three regaining normal function.
Myosin ATPase intermediate density fibers for diagnosis of reinnervation
Authors: Griffin Joe L. , Pezeshkpour Gholam H.
Published: January 2005

Myosin ATPase (pH 9.4) differentiates two muscle fiber types in healthy human muscle, while diseased muscle often contains intermediate density fibers (IDFs). We evaluated the possibility that, since almost all IDFs in pathologic muscle biopsies are changing type after reinnervation by a motor axon of the opposite type, IDFs are useful in diagnosis. In a retrospective study of 208 muscle biopsies, IDFs were seen as often as were esterase‐positive angular atrophic fibers (EPAAFs). In denervation identified by EMG and by histopathology, EPAAFs and IDFs were found much more often than were other indicators. Of biopsies diagnosed without use of IDFs as minimal histologic change or no pathologic diagnosis, 16% had IDFs with sparse EPAAFs and 21% had IDFs without EPAAFs, suggesting mild denervation with rapid reinnervation. IDFs correlate well with EPAAFs, identifying reinnervated versus denervated fibers. Type grouping reveals completed reinnervation change that may be many years old, while IDFs are changing type when biopsied and thus reveal recent reinnervation and preceding denervation. IDFs usefully belong with the histochemical indicators used to evaluate muscle disease.
Electrophysiological and ultrastructural studies on reversible neural conduction disturbance after high voltage discharge
Authors: Eickhorn Roland , Manfred Kopf , Stadler Rainer , Antoni Hermann
Published: January 2005

High‐voltage condenser discharges exerting a field strength of up to 1000 V/cm (discharge time constant 0.24‐8 msec) applied to isolated sciatic frog nerve lead to disturbances of the propagation of action potentials including transient complete block of conduction. Such conduction disturbances are normally reversible within minutes. Inhibition of the activity of the membrane–bound Na+‐K+ATPase prevents the recovery from conduction block. Withdrawal of external Ca2+ also prevents recovery, whereas blockade of protein synthesis by cycloheximide has no influence. The velocity of recovery depends on the temperature, with temperature coefficients (Q10) from 1.31 to 1.84 between 2° and 30°C. Transmission electron microscopy of nerves subjected to strong discharges shows alterations of the myelin sheath (splitting and cleft formation) which are, however, not specific for this mechanism of injury. No alterations are seen in the region of the free axoplasmic membrane of the node of Ranvier or in organelles. The results suggest a breakdown of the transmembrane ionic gradient causing the conduction disturbance.
Properties of motor unit action potentials recorded with concentric and monopolar needle electrodes: ADEMG analysis
Authors: Howard Jane E. , McGill Kevin C. , Dorfman Leslie J.
Published: January 2005

We compared the configurational and firing properties of 7270 motor unit action potentials (MUAPs) recorded with either concentric (CNE) or monopolar (MNE) needle electrodes from the brachial biceps and anterior tibial muscles of 10 healthy young adults (mean age 27 ± 4.5 years) using automatic decomposition electromyography (ADEMG). In both muscles, mean MUAP amplitude, rise rate, and number of turns were significantly greater when recorded with MNE (paired t‐test, P < 0.001 in each case). Similar findings were observed at all three tested levels of isometric contractile force: threshold, 10% of maximum voluntary contraction (MVC), and 30% MVC. In contrast, there was no significant difference between electrode types on measurements of mean MUAP duration or firing rate (P > 0.05 in each case). These findings indicate that it is acceptable to generalize normative data on MUAP duration and firing rate from one electrode type to another, but that measures of MUAP amplitude and complexity require independent normative databases.
Cold‐induced peripheral nerve damage: Involvement of touch receptors of the foot
Authors: Carter Jonathan L. , Shefner Jeremy M. , Krarup Christian
Published: January 2005

A 31‐year‐old male developed paresthesia and numbness of mainly the right foot following exposure to nonfreezing temperatures under moist conditions over a period of 1 week. The symptoms gradually improved over several months. When seen for electrophysiological studies 6 months after the injury, there was no sensory loss on clinical examination, although he continued to complain of distal numbness of the right foot. The right extensor digitorum brevis muscle was atrophic, and the distal motor latency in the peroneal nerve was prolonged. Conduction studies of the right sural nerve showed a predominantly distal diminution of the SAP evoked by electrical stimulation at the dorsum pedis. Action potentials evoked by tactile stimulation of Pacinian corpuscles showed a prolonged latency on the symptomatic side, suggesting that the most pronounced pathological changes in immersion injury may be localized to the very distal portion of the nerve at the nerve fiber‐receptor junction.
The utility of magnetic stimulation for routine peripheral nerve conduction studies
Authors: Evans Bruce A. , Litchy William J. , Daube Jasper R.
Published: January 2005

The magnetic stimulator was compared with percutaneous electrical stimulation for activation of the median nerve at the wrist in four volunteers. Magnetic stimulation was unable to achieve supramaximal stimulation without activation of the ulnar nerve. The point of nerve depolarization could not be reliably estimated from the relationship of the stimulator head to the nerve. We conclude that the magnetic stimulator coil is as yet not suitable for routine electrodiagnositic use in the peripheral nervous system.
AAEE minimonograph #32: The electrophysiologic examination in patients with radiculopathies
Authors: Wilbourn Asa J. , Aminoff Michael J.
Published: January 2005

A brief history of the evolution of radiculopathy as a clinical entity, and the use of electrodiagnostic studies to diagnose it, are provided. Root anatomy and the concept of myotomes and dermatomes are reviewed, as is the pathophysiology of radiculopathy. The value and limitations of the various electrophysiologic procedures used in the diagnosis of radiculopathies are discussed, including motor and sensory nerve conduction studies, late responses, somatosensory evoked potentials, nerve root stimulation, and the needle electrode examination. The specific muscles are enumerated which most often appear abnormal on needle electromyography with lesions of the various roots. The electrodiagnostic differentiation of root lesions from plexus lesions is described, and the various electrodiagnostic findings with lumbar canal stenosis are discussed. Finally, the value and limitations of the electrodiagnostic assessment in the evaluation of patients with suspected radiculopathies are reviewed.
Posterior femoral cutaneous neuralgia
Authors: Chutkow Jerry G.
Published: January 2005

A middle‐aged male developed a right posterior femoral cutaneous neuralgia that persisted for 10 years without any associated neurologic, electrophysiologic, or radiologic findings. Five years after onset, surgical exploration of the subgluteal area identified a venous malformation surrounding the nerve. The syndrome appears unique and exemplifies all major aspects of the sensory distribution of the nerve complex.
A comparison of EMG procedures in the carpal tunnel syndrome with clinical‐EMG correlations
Authors: White James C. , Hansen Susan R. , Johnson Richard K.
Published: January 2005

One hundred and twenty‐two patients were selected on the basis of symptoms of finger numbness and tingling thought to suggest carpal tunnel syndrome. The severity of the symptoms was graded and the patients were studied with seven established EMG procedures, motor inching to the abductor pollicis brevis and second lumbrical muscles, and sensory inching. Symptom severity was compared with the degree of nerve conduction abnormality and results from symptomatic hands with those abnormal results from patient's asymptomatic hands. Motor inching to the abductor pollicis brevis muscle was the most sensitive study and, when combined with sensory inching, gave a sensitivity of 97–100% (depending on symptom severity). Motor inching to the second lumbrical muscle alone detected the lesion site in several severely involved nerves. Guidelines are suggested with which one can estimate the likelihood that a patient's finger sensory symptoms are on the basis of carpal tunnel syndrome.
AAEE case report #16: Botulism
Authors: Pickett Jackson B.
Published: January 2005

Botulinal toxin causes a marked reduction in the number of quanta released by autonomic and motor nerve terminals. As a result it causes blurred vision, inability to move the eyes, weakness of other cranial nerve‐innervated muscles, dyspnea progressing to apnea, and generalized weakness. Electrodiagnostic findings in severe botulism can be relatively nonspecific, with low amplitude and short duration motor unit action potentials and small M wave amplitudes. A modest increment in M wave amplitude with rapid repetitive nerve stimulation may help to localize the disorder to the neuromuscular junction. Identification of the toxin in the patient's serum is diagnostic. The treatment of botulism is mainly supportive.
Silver cholinesterase immunocytochemistry: A new neuromuscular junction stain
Authors: Alderson Kathy , Pestronk Alan , Yee Woon‐Che , Drachman Daniel B.
Published: January 2005

Evaluation of morphological alterations at the neuromuscular junction associated with sprouting or other pathological changes has been limited by the inability to visualize simultaneously the multiple cell types that make up a junction. A new combined stain for the concurrent demonstration of motor nerve terminals, cholinesterase, and Schwann cell myelin and other antigens at neuromuscular junctions using bromoindoxyl acetate dye staining for cholinesterase, silver‐gold impregnation for nerve terminals, and immunocytochemistry of selected antigens is described. The clarity of the stain permits graphic demonstration of the alteration of neuromuscular junction components during sprouting as well as other pathological changes.
Motor neuropathy with multifocal conduction blocks
Authors: van den Bergh Peter , Logigian Eric L. , Kelly John J.
Published: January 2005

We describe a patient with a chronic, symmetric, monophasic, acquired, pure motor, demyelinating polyneuropathy. Electrodiagnostic studies showed the presence of multifocal conduction blocks in motor nerves at sites not prone to compression. A sural nerve biopsy was normal. The patient responded to immunosuppressive therapy and plasma exchange. We postulate that this disorder is an unusual variant of chronic inflammatory polyradiculoneuropathy.
Asymptomatic hyper‐CK‐emia: An electrophysiologic and histopathologic study
Authors: Joy Juan L. , Oh Shin J.
Published: January 2005

Since the popularization of routine creatine kinase (CK) measurement, an increasing number of patients with unexplained CK elevation (“asymptomatic hyper‐CK‐emia”) are being identified. We studied 19 patients with persistent CK elevation of unknown etiology with electromyography (EMG) and muscle biopsy. Needle EMG was abnormal in 14 patients. Muscle biopsy was positive in all individuals with abnormal EMG and in one patient with normal EMG. Diagnoses included polymyositis in five patients, morphologically nonspecific myopathy in three, mitochondrial myopathy in two, and sarcoid myopathy, central core disease, multicore disease, inclusion body myopathy, and McArdle's disease in one case, respectively. Five patients with abnormal biopsies developed weakness within 1 year of presentation. We conclude that persistent asymptomatic CK elevation represents mild or early myopathy in a majority of cases.
Muscle pain associated with tubular aggregates and structures resembling cylindrical spirals
Authors: Danon Moris J. , Carpenter Stirling , Harati Yadollah
Published: January 2005

A 42‐year‐old man complained of muscle pain in the legs and episodes of left‐sided limb weakness. Light microscopy of his quadriceps muscle showed abundant subsarcolemmal accumulations with typical histochemical features for tubular aggregates. Electron microscopy showed areas filled with tubular aggregates and vesicular profiles. Scattered within some of the tubular aggregates circular profiles reminiscent of cylindrical spirals were seen. The presence of structures resembling cylindrical spirals within tubular aggregates suggest that they may arise from a component of the sarcoplasmic reticulum. There appears to be an intimate relationship between myalgia and these various types of abnormal membranous profiles; however, the pathophysiology remains to be elucidated.
The application of nerve conduction and clinical studies to genetic counseling in hereditary motor and sensory neuropathy type I
Authors: Berciano Josée , Combarros Onofre , Calleja Jesús , Polo Josée M. , Leno Carlos
Published: January 2005

One hundred and thirty two individuals at risk for hereditary motor and sensory neuropathy (HMSN) type I from 11 unrelated families were evaluated by physical examination. Motor conduction velocity (MCV) studies of median and/or peroneal nerves were performed on 99 of them. Seventy‐three subjects were found to be affected. In all age categories including the first decade of life, the ratio of affected individuals at risk did not significantly differ from the expected 1:1 ratio; that is, penetrance of the gene was complete. The majority of affected members in the first decade had no clinical features considered diagnostic of peroneal muscular atrophy syndrome, and full clinical expression developed in the second decade. Marked slowing of MCV was already present in the early years of life, even as young as 6 months. Moreover serial MCV studies carried out throughout the first year of life in an affected girl showed no physiological increase in conduction velocity. For purposes of genetic counseling, our experience suggests that, starting from 6 months of age, a clinically and electrophysiologically normal subject has a zero risk of having inherited the HMSN type I gene. However given the limited numbers in this series, infants at risk with normal clinical evaluation and MCVs should be followed up yearly up to 5 years of age.
Muscle protein synthesis in steroid‐induced proximal myopathy: A case report
Authors: Pacy Paul J. , Halliday David
Published: January 2005

A 51‐year‐old man with proven adenosquamous carcinoma of the lung presented with clinically acute steroid myopathy. Postabsorptive whole body leucine kinetics and fractional mixed muscle protein synthesis rate (MPSR) were determined by a steady‐state approach during continuous L‐(1–13C) leucine infusion. Plasma 13C α‐ketoisocaproic acid enrichment was taken to represent labeling of the precursor pool. Postabsorptive whole body leucine flux and protein synthesis were less than the 1 in 500 confidence intervals of control values. Fractional MPSR was significantly reduced (P < 0.01). Simultaneous calculation of MPSR from two adjacent sites was in excellent agreement (0.0372 and 0.0395% h−1). This is the first report that steroid myopathy is associated with reduced whole body protein synthesis and fractional MPSR in man.
Thyrotoxic periodic paralysis and the sodium/potassium pump
Authors: Marx Alexander , Ruppersberg Johann Peter , Pietrzyk Christian , Rüdel Reinhardt
Published: January 2005

The hypothesis of altered Na+/K+ transport in thyrotoxic periodic paralysis (TPP) was tested in an investigation of the K+ influx into erythrocytes from two patients with episodes of thyrotoxic muscle weakness. A patient with primary hypokalemic periodic paralysis (HPP) and three healthy volunteers served as controls. The TPP patients were of Oriental and Caucasian origin and differed in their clinical symptoms. For the Caucasian patient, the Na+ content of the erythrocytes was twice the control, for the Oriental patient it was normal. The K+ dependence of the ouabain‐inhibitable K+ influx (the pump action) was also abnormal in the Caucasian patient, the flux being 70% of control at 2 mM [K+]e and normal at 4 mM[K+]e. The K+ influx was normal in the Oriental patient. By contrast, the K+ leak of the cells was normal in the Caucasian and was increased in the Oriental patient. The pump/leak ratio was thus reduced in both TPP patients. All parameters investigated were normal in the patient with primary HPP. It is concluded that the ion transport systems of muscle may be altered in TPP, but that the pathomechanism might be different in the rare Caucasian cases and the rather more common Oriental cases.
Immunohistochemical differential distribution of S‐100α and S‐100β in the peripheral nervous system of the rat
Authors: Sugimura Kimiya , Haimoto Hajime , Nagura Hiroshi , Kato Kanefusa , Takahashi Akira
Published: January 2005

The localization of the α subunit of the S‐100 protein (S‐100α) and β subunit (S‐100β) was studied in the peripheral nervous system of the rat. In peripheral nerves, S‐100α and S‐100β were found in the cytoplasm of Schwann cells. Axons were positively stained in part by S‐100α and almost totally by S‐100β. In the dorsal root ganglia, S‐100β was found in satellite cells and their processes and in some neurons. S‐100β was found in more of the large neurons, but almost all of the small neurons were negative for S‐100β. In the anterior horn cells, S‐100β staining was stronger than that of S‐100β. In Schwann cells, both S‐100β and S‐100β were present on the rough endoplasmic reticulum, free ribosomes, and nucleus, as seen by electron microscopy. The S‐100α and S‐100β in axons were associated with microtubules and neurofilaments.
Distribution of nerve conduction velocities in acute thallium poisoning
Authors: Yokoyama Kazuhito , Shunichi Araki , Abe Haruo
Published: January 2005

To assess the effects of thallium on the conduction velocities of faster and slower nerve fibers, the distribution of conduction velocities in sensory fibers of the median nerve was examined in a patient with acute thallium poisoning 2 and 11 months after the onset of symptoms. In the first examination, the patient showed evidence of a distal sensorimotor neuropathy and had an elevated urinary thallium concentration (3.5 mg/L); the conduction velocities of faster fibers were below the normal lower limit, whereas those of slower fibers were within normal limits. At the second examination, the conduction velocities of all faster and slower fibers increased and were within normal limits: clinical signs and symptoms of neuropathy almost disappeared. It is concluded that the conduction velocities of faster fibers significantly decrease in an early stage of acute thallium poisoning and recover following recuperation from the poisoning; those of slower fibers are minimally affected and then improve.
Cortical magnetic stimulation in amyotrophic lateral sclerosis
Authors: Eisen Andrew , Shytbel Wayne , Murphy Kirsten , Hoirch Maureen
Published: January 2005

Forty patients with ALS underwent cortical magnetic stimulation. Twelve had marked pseudobulbar signs; in these motor evoked potentials (MEPs) could not be elicited. Mean MEP latencies in the others, who had predominantnantly lower motor neuron signs, measured 23.3±2.1 msec (thenar), 18.7±5.3 msec (EDC), and 13.4±2.9 msec (biceps), respectively. These values were significantly longer (P > 0.001) compared with normal values (n=35), which measured 20.2±1.6, 14.2±1.7, and 9.4±1.7 msec, respectively. MEP amplitude was often markedly reduced (less than 15% of the M wave) compared with a normal mean of 39.5±13.0%. Overall abnormal MEPs (delayed, absent, or reduced in amplitude) approached 100%. It is argued that measuring central motor delay, which was not significantly different in the patients compared with normals, is subject to error in ALS.
Familial hypertrophic cardiomyopathy and muscle carnitine deficiency
Authors: Bautista J. , Rafel E. , Martinez A. , Sainz I. , Herrera J. , Segura L. , Chinchon I.
Published: January 2005

Five members of the same family, along three generations, presented with hypertrophic cardiomyopathy. Neurological examination, muscle strength, electromyography, and serum creatine kinase were normal. Skeletal muscle biopsy showed abnormal lipid accumulation and carnitine deficiency. In three patients the cardiac symptoms and echocardiographic findings improved after treatment withL‐carnitine, 3–4 g daily, and a long‐chain fattyacid‐free diet.
Resealed fiber segments for the study of the pathophysiology of human skeletal muscle
Authors: Lehmann‐Horn Frank , Iaizzo Paul A.
Published: January 2005

The usefulness of long fiber segments for the study of the pathophysiology of human skeletal muscle was evaluated. Immediately after biopsy, the fiber segments were depolarized. Within 3 hours the cut ends resealed, and if the segments were ≥ ‐ 2.5 cm long they regained normal resting membrane potentials (i.e., negative to −80 mV). Miniture endplate potentials, endplate potentials, action potentials, the current‐voltage relationship, and the resting intracellular Ca2+ concentration of the resealed fiber segments were similar to those in fibers that were intact from tendon to tenon. In addition, specific properties of intact fibers obtained from patients with various neuromuscular diseases were preserved in the resealed fiber segments prepared from the same patients or patients with the same diseases. These segments are easily obtained as a routine muscle biopsy performed under local anesthesia; they provide valuable preparations for the study of the pathophysiology of human skeletal muscle as well as for in vitro pharmacological tests.
Carpal tunnel area as a risk factor for carpal tunnel syndrome
Authors: Winn Francis J. , Habes Daniel J.
Published: January 2005

Carpal tunnel area was investigated as a risk factor for carpal tunnel syndrome (CTS). It was hypothesized that if canal area is a risk fctor for the syndrome, individuals who develop the syndrome should have smaller carpal canal areas than those who remain free of the syndrome. Sixty‐one subjects, approximately equally divided by sex, age group, and diagnosis, were examined. A measurement of cross‐sectional areas of the carpal canal by computerized axial tomography indicated that individualsdiagnosed as carpal tunnel patients had significantly larger carpal canal areas than controls. The results indicate that a small carpal canal aresa does not appear to be a risk factor for carpal tunnel syndrome.