Measurement Of Motor Nerve Conduction Velocity Research Articles

Electroneurography of the ulnar nerve in dogs

Electroneurography as one of the electrodiagnostic techniques is used to measure the speed of action potential which is propagated down the nerve after stimulation. It gives information about normal functioning of the peripheral nerves. The aim of this study was to evaluate the applicability of a new electroneurographic technique by performing motor nerve conduction velocity measurements in the ulnar nerve with surface stimulating electrodes in healthy dogs, to correlate the obtained data by age, limb length, rectal temperature, and sex; and to compare these results with published findings utilizing needle stimulating electrodes. The study was performed in 24 clinically healthy dogs without anaesthesia. Rectal temperatures and limb lengths were measured in all individuals. There were significant correlations among several indicators (age, rectal temperature, limb length, conduction velocity, latency and duration of compound muscle action potentials). Limb length was found to have a significant effect on the duration of the compound muscle action potential from both stimulation sites (proximal/distal; r = 0.71, r = 0.68, P < 0.01), but there was no effect on the conduction velocity or amplitude of the action potentials. There was no significant difference (P > 0.05) in the measured indicators between males and females, even though females had a higher mean conduction velocity than males. These results prove that conduction velocity measurements in dogs could be performed non-invasively, without a danger of infection or haematomas or complications with anaesthesia, which is more favourable and time-saving for clinical practice, and more comfortable for patients.

Ataxia with loss of Purkinje cells in a mouse model for Refsum disease

Refsum disease is caused by a deficiency of phytanoyl-CoA hydroxylase (PHYH), the first enzyme of the peroxisomal alpha-oxidation system, resulting in the accumulation of the branched-chain fatty acid phytanic acid. The main clinical symptoms are polyneuropathy, cerebellar ataxia, and retinitis pigmentosa. To study the pathogenesis of Refsum disease, we generated and characterized a Phyh knockout mouse. We studied the pathological effects of phytanic acid accumulation in Phyh(-/-) mice fed a diet supplemented with phytol, the precursor of phytanic acid. Phytanic acid accumulation caused a reduction in body weight, hepatic steatosis, and testicular atrophy with loss of spermatogonia. Phenotype assessment using the SHIRPA protocol and subsequent automated gait analysis using the CatWalk system revealed unsteady gait with strongly reduced paw print area for both fore- and hindpaws and reduced base of support for the hindpaws. Histochemical analyses in the CNS showed astrocytosis and up-regulation of calcium-binding proteins. In addition, a loss of Purkinje cells in the cerebellum was observed. No demyelination was present in the CNS. Motor nerve conduction velocity measurements revealed a peripheral neuropathy. Our results show that, in the mouse, high phytanic acid levels cause a peripheral neuropathy and ataxia with loss of Purkinje cells. These findings provide important insights in the pathophysiology of Refsum disease.

ベル麻ひの病態に関する電気生理学的研究 Ｃｏｌｌｉｓｉｏｎ法（Ｈｏｐｆ）による顔面神経伝導速度分布の測定

The etiology of Bell's palsy is still obscure, but the hypothesis that hypoxia and compression of the nerve induced by edema in the Fallopian canal are the main causes of Bell's palsy is widely accepted. Tojima (1988) reported that the motor nerve conduction velocity (MCV) gradually decreased as degeneration of the nerve fibers progressed in Bell's palsy. The majority of facial nerve fibers are myelinated, and the greater the fiber diameter, the faster the conduction velocity. For this reason, Tojima suggested that Wallerian degeneration in Bell's palsy would begin from the thicker myelinated fibers. The measurement of MCV, however, reveals only the activities of the fastest velocity motor nerve fiber in the nerve trunk. This weak point can be resolved by measurement of the distribution of nerve conduction velocities (DNCV), which was introduced by Hopf in 1962 as the collision method. In the present report, the DNCV of facial nerve was measured using the collision method to estimate the distribution of the diameter of nerve fibers in normal subjects and patients with Bell's palsy and to elucidate the pathophysiology of Bell's palsy. The subjects were 14 normal adults (19 measurements) and 14 patients with Bell's palsy who visited our university clinic within 7 days to 18 days after onset, with no other complications such as diabetes. Results obtained are as follows. 1) The mean DNCV in 14 normal subjects (19 measurements) was unimodal, showing a peak at 20 to 22 m/s. 2) In DNCVs of patients with Bell's palsy, loss of thicker fibers with faster conduction velocity was recognized (11/14, 79%).(ABSTRACT TRUNCATED AT 250 WORDS)

Neuromuscular effects of acute 2,4-dichlorophenoxyacetic acid (2,4-D) exposure in dogs

2,4-Dichlorophenoxyacetic acid (2,4-D) was administered once orally to adult female mongrel dogs at 0, 25, 50, 75, 100 or 125 mg/kg of body weight (n = 4 per group). Clinical neurological examinations, electromyography (EMG) and motor nerve conduction velocity measurements were carried out before exposure, and on days 1, 3, 7, 14, 21 and 28 post-exposure. On day 7, two dogs per group were killed. Samples of the medial and lateral plantar nerves were removed for teased fiber and semi-thin section analysis; samples of appendicular muscles were removed for histology and histochemistry. Necropsy included histopathological examination of the brain and spinal cord at multiple levels. Remaining dogs were killed on day 28 and their tissues were processed similarly. Transient generalized myotonic discharges were found in skeletal muscles of dogs receiving 50 mg/kg or more of 2,4-D. A few dogs in the higher dosage groups also had mild muscle stiffness, myotonic dimpling and/or lethargy, lasting up to 3 days post-exposure. Other parameters remained within normal limits.

Industrial lead poisoning in China over the past 33 years

This paper is a review of the 48 articles in scientific journals and special reports of investigations emanating from the author's department involving 2504 subjects. During the past 33 years, as a result of the establishment of health and antiepidemic stations throughout the country, the enactment of hygienic standards, and the setting up of the reporting system for industrial poisoning and occupational diseases, the air lead level has been reduced from 10 mg/m 3 in the years soon after liberation (1949) to below 0.03 mg/m 3 at present. Severe plumbism has disappeared. Some mild cases, however, could still be found among workers in lead smelters and electric battery plants. Great advances have been made in techniques for early diagnosis of lead poisoning. Blood lead, urine lead, aminolevulinic dehydrase, free erythrocyte protoporphyrin, and zinc protoporphyrin (ZnPP) have been used as criteria for lead exposure. For the purpose of preventive monitoring, ZnPP as a screening index is the first choice. Behavioral function and sensory and motor nerve conduction velocity measurements of median nerve might also be used for the investigation of lead exposure. The maximum allowable concentration of 0.03 mg/m 3 for air lead level in the workshop, in agreement with the results of a nationwide lead industry investigation, has been proven safe. There is also the need to monitor the air lead level and blood lead level in the general population and children living adjacent to a lead industry.

The Guillain-Barré syndrome: clinical and electroneuromyographic studies.

Clinical and electrophysiological studies were carried out on 39 patients with the Guillain-Barré syndrome to evaluate which elements were of prognostic value during the acute phase. Residual clinical signs such as motor weakness and absent patellar tendon reflexes were found in 16 (52%) of those patients who had had a preceding illness. Persistence of deficit was significantly correlated to age at onset, the degree of quadriparesis and loss of deep sensation in the acute phase. Of the 10 patients who showed a reduction in motor nerve conduction velocity (MCV) in the early stage, 8 (80%) revealed significantly residual clinical symptoms at follow-up. There was a tendency for the incidence of residual signs to be more common in the patients with slowing of mixed nerve conduction velocity, and prolonged latency of H-wave and the residual latency. Nerve conduction studies, especially measurement of MCV, were of value as a reliable prognostic indicator in this syndrome.