Maximal Motor Nerve Conduction Velocities Research Articles

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy.

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy.

Ten-year follow-up of peripheral nerve function in patients with familial amyloid polyneuropathy after liver transplantation

The electrophysiological long-term effects of liver transplantation on peripheral nerve function in patients with familial amyloid polyneuropathy (FAP) have not been evaluated. Eight FAP patients with a proven ATTRVal30Met gene were observed for 10 years after liver transplantation. We performed repeated measurement of maximal motor nerve conduction velocity (MCV), distal latency, size of compound muscle action potential (CMAP) and maximal sensory nerve conduction velocity (SCV) in both the ulnar and tibial nerves. We also recorded the coefficients of variance in the R-R interval on the electrocardiogram (CV(R-R)). Some autonomic symptoms subsided but motor and sensory symptoms 10 years after transplantation were either slightly improved or almost the same as before surgery in 7 of 8 patients. These 7 have returned to their previous social lives including their jobs. The MCV of the tibial nerve slightly improved, and other parameters of motor and sensory nerve function and CV(R-R) did not show any deterioration during the 10-year observation period. Liver transplantation can halt the progression of peripheral neuropathy in FAP patients.

Effects of Pesticides on the Peripheral and Central Nervous System in Tobacco Farmers in Malaysia: Studies on Peripheral Nerve Conduction, Brain-Evoked Potentials and Computerized Posturography

We examined the effects of pesticides on the central and peripheral nervous system in the setting of a tobacco farm at a developing country. Maximal motor and sensory nerve conduction velocities (MCV and SCV, respectively) in the median, sural and tibial nerves, postural sway, and brain-evoked potentials (auditory event-related and visual-evoked potentials) were measured in 80 male tobacco farmers and age- and sex-matched 40 controls in Kelantan, Malaysia. Median SCV (finger-wrist) in farmers using Delsen (mancozeb, dithiocarbamate fungicide), who showed significant decrease of serum cholinesterase activities, were significantly lower compared with the controls. Sural SCV in farmers using Fastac (alpha-cypermethrin, pyrethroid insecticide) and median MCV (elbow-wrist) in farmers using Tamex (butralin, dinitroaniline herbicide) were significantly slowed compared with their respective controls. In Delsen (mancozeb, dithiocarbamate) users, the power of postural sway of 0-1 Hz was significantly larger than that in the controls both in the anterior-posterior direction with eyes open and in the right-left direction with eyes closed. The former type of sway was also significantly increased in Tamaron (methamidophos, organophosphorus insecticide) users. In conclusion, nerve conduction velocities and postural sway seem to be sensitive indicators of the effects of pesticides on the central and peripheral nervous system.

Cyclosporin A in treatment of refractory patients with chronic inflammatory demyelinating polyradiculoneuropathy

To investigate the therapeutic efficacy of cyclosporin A (CyA) in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), a microemulsion form of this drug (Neoral®) was orally given to seven patients with the disease who were unresponsive or resistant to conventional therapies. The daily dose of CyA was carefully controlled in order to keep the plasma trough concentration between 100 and 150 ng/ml. Within 1 month of initiation of CyA, all patients subjectively showed improvement of clinical symptoms, while both modified Rankin and INCAT disability scores were significantly decreased ( p<0.05) and grip strength was significantly increased ( p<0.05) 3 months after initiation compared with before. Total protein in the cerebrospinal fluid was significantly decreased 3 and 6 months after starting CyA ( p<0.05). Although the maximal motor nerve conduction velocity showed a significant improvement in the median nerve 1 to 1.5 years after commencement of CyA ( p<0.05), there were no significant changes in any other neurophysiological parameters. One patient with anti-sulphoglucuronyl paragloboside IgM antibodies gradually became resistant to CyA, but the rest have since been in good neurological condition without complications ascribable to this drug. These results suggest that oral CyA may be effective even for refractory cases with CIDP. CyA should be actively considered as a therapeutic option when patients with CIDP are resistant to conventional treatment.

Corticosteroids for chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy is a peripheral neuropathy caused by peripheral nerve inflammation probably due to autoimmunity and would be expected to benefit from corticosteroids. Non-randomised studies suggest that corticosteroids are often beneficial. To evaluate the efficacy of corticosteroids for treating chronic inflammatory demyelinating polyradiculoneuropathy. Search of the Cochrane Neuromuscular Disease Group register for randomised trials of corticosteroids treatment for chronic inflammatory demyelinating polyradiculoneuropathy and enquiry from subject experts. Types of studies: All randomised or quasi-randomised trials Types of Participants: All patients with chronic inflammatory demyelinating polyradiculoneuropathy who were diagnosed by an internationally accepted definition. Types of interventions: Treatment with any form of corticosteroids or adrenocorticotropic hormone. Types of outcome measures: Change in disability 12 weeks after randomisation. 1. Change in impairment 12 weeks after randomisation. 2. Change in maximum motor nerve conduction velocity or compound muscle action potential amplitude after 12 weeks. 3. Side effects of corticosteroids. One author extracted the data and the other checked them. We identified one randomised controlled trial, an open study in which 19 corticosteroids treated patients showed more improvement in impairment than 16 untreated controls after 12 weeks. Experience from large non-randomised studies suggests that steroids are beneficial. A single randomised controlled trial with 35 participants provided weak evidence to support the conclusion from non-randomised studies that oral corticosteroids reduce impairment in chronic inflammatory demyelinating polyradiculoneuropathy. Corticosteroids are known to have serious long term side effects. The long term risk and benefits have not been adequately studied.

Maximal and minimal motor conduction velocity in amyotrophic lateral sclerosis and X-linked bulbospinal muscular atrophy measured by Harayama's collision method.

Measurement of the maximal (Vmax) and minimal (Vmin) motor nerve conduction velocities was performed in amyotrophic lateral sclerosis (ALS), bulbospinal muscular atrophy (BSMA), and control subjects. The collision method as described initially by Harayama and coworkers was used. This allowed for the correction of the velocity recovery effect (VRE) in Hopf's original method. The purpose of this study is to clarify the controversial results regarding the Vmin and the difference between Vmax and Vmin (Vmax-Vmin) in ALS and to compare these results with BSMA, and clarify the usefulness of Harayama's method. In ALS, a reduction of Vmax and Vmin, and an increase of Vmax-Vmin were found in both median and posterior tibial nerve. In BSMA, a reduction of Vmin and an increase of Vmax-Vmin in the median nerve were noted. Some patients whose results of conventional nerve conduction study were entirely within normal range showed abnormal results in Vmin and/or Vmax-Vmin. These results suggest that the correction of VRE is essential to determine a Vmin, and motor fibers with abnormally slow conduction velocities were present in ALS and BSMA. Harayama's collision method is useful to detect abnormalities of motor fibers with submaximal conduction velocities.

1-Bromopropane, an alternative to ozone layer depleting solvents, is dose-dependently neurotoxic to rats in long-term inhalation exposure.

1-Bromopropane has been newly introduced as an alternative to ozone layer-depleting solvents. We aimed to clarify the dose-dependent effects of 1-bromopropane on the nervous system. Forty-four Wistar male rats were randomly divided into 4 groups of 11 each. The groups were exposed to 200, 400, or 800 ppm of 1-bromopropane or only fresh air 8 h per day for 12 weeks. Grip strength of forelimbs and hind limbs, maximum motor nerve conduction velocity (MCV), and distal latency (DL) of the tail nerve were measured in 9 rats of each group every 4 weeks. The other 2 rats of each group were perfused at the end of the experiment for morphological examinations. The rats of the 800-ppm group showed poor kicking and were not able to stand still on the slope. After a 12-week exposure, forelimb grip strength decreased significantly at 800 ppm and hind limb grip strength decreased significantly at both 400 and 800 ppm or after a 12-week exposure. MCV and DL of the tail nerve deteriorated significantly at 800 ppm. Ovoid or bubble-like debris of myelin sheaths was prominent in the unraveled muscular branch of the posterior tibial nerve in the 800-ppm group. Swelling of preterminal axons in the gracile nucleus increased in a dose-dependent manner. Plasma creatine phosphokinase (CPK) decreased dose-dependently with significant changes at 400 and 800 ppm. 1-Bromopropane induced weakness in the muscle strength of rat limbs and deterioration of MCV and DL in a dose-dependent manner, with morphological changes in peripheral nerve and preterminal axon in the gracile nucleus. 1-Bromopropane may be seriously neurotoxic to humans and should thus be used carefully in the workplace.

Diagnostic sensitivity of motor nerve conduction studies in ulnar neuropathy at the elbow.

Seventy-six patients with ulnar neuropathy at the elbow were divided into 3 classes (Grades I, II, and III) according to their clinical features and the maximal motor nerve conduction velocity (MCV), and the amplitude ratios at the across-elbow segment were retrospectively analyzed. To determine the criteria for abnormality, a control study was conducted on 150 healthy volunteers ranging in age from 20 to 89 years (6 age groups). The normal value for MCV could be set for two age groups: those under 60 and those over 60 years old. The 95% confidence limit was 54m/s for the former and 50m/s for the latter. There was no statistically significant difference in the amplitude ratio among the age groups. The confidence limit was set uniformly at 0.82 (above elbow/below elbow). An abnormality in either MCV or the amplitude ratio was found in 66.7% of Grade I (recent and mild symptoms), 89.7% of Grade II (persistent symptoms), and 100% of Grade III cases (marked intrinsic muscle atrophy). Evaluation using the combination of MCV and the amplitude ratio, considering the age-related normal value, appeared to be useful in establishing a differential diagnosis of ulnar neuropathy at the elbow.

Assessment of the Distribution of Nerve Conduction Velocities in Alcoholics

To assess the effects of chronic alcohol ingestion on the faster and slower nerve fibers (alpha fiber group) in the peripheral nervous system, the distribution of nerve conduction velocities (DCV) and conventional maximal motor and sensory nerve conduction velocities (MCV and SCV) in the median nerve were measured in 23 male patients with severe alcoholic dependency (DSM-IIl-R), aged 30–64 (mean, 50) years, and in 23 age-matched healthy men. The DCV was expressed by the conduction velocities below which 10, 20, . , 80, and 90% of active fibers lie (V10, V20, . , V80, and V90 velocities). The V40 to V90 velocities of the DCV were significantly slower in the alcoholics than in the control subjects; the SCV and MCV in the alcoholics were also significantly slowed. These findings suggest that the faster large myelinated nerve fibers are more sensitive to chronic alcohol ingestion than the slower large myelinated nerve fibers.

Cardiac autonomic dysfunction in rotogravure printers exposed to toluene in relation to peripheral nerve conduction.

The autonomic nervous effects of toluene remain less clear. To clarify this neurotoxicity, ten rotogravure printers and the same number of age-matched unexposed controls were examined, by using the coefficient of variation in electrocardiographic R-R intervals (CVRR), the distribution of nerve conduction velocities (DCV) and the maximal motor and sensory nerve conduction velocities (MCV and SCV) in the median nerve. Also, the C-CVHF and C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) were computed from component spectral powers using autoregressive spectral and component analyses. These printers had been exposed to toluene (estimated exposure levels of toluene at 83 ppm) for 1-36 years. The CVRR and C-CVHF were significantly lower in the printers than in the controls. No significant difference between the printers and the controls was found in either any DCV parameters or the SCV in the forearm, except the MCV and the SCV in the palm. In the light of previous work on the brainstem/hippocampus damages due to toluene, these data suggest that toluene causes potential damages in the central autonomic nervous system, mainly parasympathetic hypoactivity.

Maximal and minimal motor nerve conduction velocities determined by a collision method: correlation with axonal conduction velocity of type-identified motor units

Maximal and minimal motor nerve conduction velocities of the medial gastrocnemius (MG) muscle nerve were measured by a new collision method in 20 rats of 8–9 weeks of age; the rate of tension increase produced by the muscle was also recorded. Single motor unit analysis in the other 20 rats obtained axonal conduction velocity and contractile properties of type-identified MG motor units. Comparison of the data from these experiments revealed that the maximal and minimal motor nerve conduction velocities obtained by this collision method were most likely to be the axonal conduction velocity of fast-twitch and slow-twitch motor units, respectively. Therefore, these motor nerve conduction velocities in man may also be used as functional parameters of human fast-twitch and slow-twitch motor units, respectively.

Maximal and minimal motor nerve conduction velocities in patients with motor neuron diseases: Correlation with age of onset and duration of illness

We measured the maximal and minimal motor nerve conduction velocities of the ulnar nerve in 17 patients with spinal muscular atrophy (SMA), 27 patients with amyotrophic lateral sclerosis (ALS), and 40 age-matched control subjects. Crude values of the maximal and minimal motor nerve conduction velocities were reduced in both patient groups, but their difference in each patient was not statistically different from that of a control subject. The conduction velocities adjusted according to each patient's age were faster in SMA patients than in ALS patients. Among patients with either ALS or SMA, the age-adjusted conduction velocities were larger in those who had developed the disease at younger ages and suffered from it for shorter periods of time. These findings suggest that the motor nerve fibers regenerate more in younger patients in the early stages of the disease, particularly in SMA.

Normal maximal and minimal motor nerve conduction velocities in adults determined by a collision method

Using a new collision method, we measured motor nerve conduction velocities of the ulnar nerve in the forearm and the action potential amplitude of the abductor digiti minimi muscle on 60 adults, ages 20 to 82 years and apparently free from diseases of the peripheral nervous system. Both maximal and minimal motor nerve conduction velocities were linear functions of age; 64.42-0.05 age and 60.45-0.12 age, respectively. The percentage of the minimal to the maximal motor nerve conduction velocities was expressed as 94.45-0.13 age. The maximum amplitude of evoked muscle action potentials was also correlated with age. This novel method may be useful in detecting pathology of motor nerve fibers which results in a decrease in submaximal conduction velocities.

Electromyographic assessment of the neuromuscular blockade produced in vivo by anatoxin-a in the rat

The indirectly evoked compound action potentials (ECAP) of the plantar muscles of the rat were used to investigate the pharmacodynamics in vivo of the neuromuscular blockade produced by anatoxin-a. Onset time to maximum depression and the magnitude of maximum depression in amplitude of the ECAP were dose-dependent. The mean maximum percent depression (±S.D.) of the ECAP induced by single, supramaximal stimulations of the posterior tibial nerve after i.v. doses of (+)anatoxin-a hydrochloride at 0, 50, 100, 200 and 800 μg/kg were 3 (4), 53 (15), 82 (7), 95 (2), and 100 (1), respectively. The ED 50 (95% confidence limits) for depression of the ECAP was 47 mg/kg (39–57 μg/kg). Rats administered 200 μg/kg or less of (+)anatoxin-a hydrochloride had 75% return of the pretoxin amplitude of the ECAP within 93 min. Animals dosed at 800 μg/kg did not have return of neuromuscular function and died despite mechanical ventilation, suggesting a lethal mechanism(s) of action in addition to respiratory paralysis. Percent decrements (±S.D.) in the amplitude of the fourth ECAP following repetitive stimulation at 10 Hz were 6 (5), 13 (22), 46 (18) and 59 (8) from (+)anatoxin-a hydrochloride given i.v. at 0, 50, 100 and 200 μg/kg, respectively. The decrement observed following repetitive stimulation was attributed to a presynaptic site of action. No change in maximal motor nerve conduction velocity or latency of the ECAP was observed after i.v. administration of (+)anatoxin-a hydrochloride at 100 μg/kg. LD 50 values (95% confidence limits) for anatoxin-a administered i.v. to mice were 386 μg/kg (365–408 μg/kg, for (+)anatoxin-a hydrochloride and 913 μg/kg (846–985 μg/kg) for racemic anatoxin-a hydrochloride. No deaths were observed in mice after i.p. administration of(−)anatoxin-a hydrochloride at doses up to 73 mg/kg.

Relation between Height and the Maximum Conduction Velocity of the Ulnar Motor Nerve in Human Subjects.

The maximum motor nerve conduction velocity of the right and left ulnar motor nerve was measured in more than 650 healthy medical students of both sexes. There was no side difference in the maximum conduction velocity. The shorter person has a statistically significant higher conduction velocity than the taller person. Comparison of students of both sexes showed a slightly higher conduction velocity in females. However, with regard to its relation to height, the conduction velocity was higher in males.

Biochemical and neurophysiological parameters in hemodialyzed patients with chronic renal failure

Serum concentrations of accumulated solutes, standard clinical biochemistry, and parameters of clinical neuropathy, were determined in hemodialyzed patients with chronic renal failure. Analyses by high-performance liquid chromatography included creatinine, pseudouridine, urate, p-hydroxyhippuric acid, hippuric acid, indoxylsulfate, tryptophan, tyrosine, 3-indoleacetic acid, and a number of as-yet unidentified solutes. Standard biochemical parameters were measured; aluminium, parathyroid hormone, serum electrolytes and enzymes, hemoglobin, bilirubin, phosphate and urea. Measures of clinical neuropathy were: maximal motor nerve conduction velocities, and Hoffmann reflex latency. Several solutes had higher concentrations when nerve function was impaired. Serum total LDH, and total calcium levels correlated positively with values of the Hoffmann reflex, as did serum hippuric acid concentrations. Concentrations of p-hydroxyhippuric acid and two fluorescent compounds correlated negatively with motor nerve conduction velocities. In principal component analysis a number of ‘organic acid-like’ substances, like hippuric acid and p-hydroxyhippuric acid, were shown to associate multivariately with the neurophysiological variables while urea, creatinine, urate and phosphate were not.

Maximal and minimal motor nerve conduction velocities in amyotrophic lateral sclerosis.

In 15 patients with amyotrophic lateral sclerosis (ALS) and 20 age-matched control subjects, we measured the maximal and minimal motor nerve conduction velocities of the ulnar nerve as well as the action potential amplitude of the abductor digiti minimi muscle. Both maximal and minimal motor nerve conduction velocities in ALS patients were significantly lower than those in the control group. However, the difference between the maximal and minimal conduction velocities in each ALS patient was not statistically different from that in each control subject. The maximal action potential amplitude of the muscle in the ALS patients was significantly smaller than that in the control group.

Electrophysiological study of neuromuscular function in a population poisoned by lead

A comprehensive electrophysiological examination of the peripheral nervous system was carried out in 12 patients who proved to be toxicated with lead (high lead blood levels, and diminished activity of the delta-aminolevulinate dehydratase, ALA D, in erythrocytes). Maximal motor nerve conduction velocities and terminal latencies were investigated in the median, radial and deep peroneal nerves. Also the amplitude of the evoked muscle response (M wave) was measured in thenar, extensor longus and extensor digitorium brevis muscles. Sensory conduction velocity and amplitude of the nerve compound action potential were measured at the median nerve. Tibialis anterior muscle responses to deep peroneal nerve repetitive stimulation were also explored. Conventional needle electromyogram was performed in the deltoid and tibialis anterior muscles. Slight diminished motor and sensory conduction velocities were found as well as a reduction of the amplitude of the evoked muscle response of the compound sensory action potential. Four out of the 12 patients tested showed either decremental or incremental amplitude of the muscle response with nerve repetitive stimulation. A electromyographical diminished interference pattern was found in all patients tested. Most of the remaining motor unit potentials were fragmented or polyphasic. Just one patient disclosed potentials of enhanced duration and amplitude. No relationship was found between blood lead levels or ALA D erythrocytes concentration and the different electrophysiological tests performed, except between reduced ALA D concentration and diminished amplitudes of the M wave and of the sensory compound action potential, and also between ALA D and diminished radial motor conduction velocity.(ABSTRACT TRUNCATED AT 250 WORDS)

Threshold effect in lead-induced peripheral neuropathy

We previously demonstrated a negative correlation between blood lead level and motor nerve conduction velocity in 202 asymptomatic 5 to 9-year-old children living near a lead smelter in Idaho. Blood lead levels ranged from 13 to 97 micrograms/dL. To determine whether a threshold exists between blood lead level and maximal motor nerve conduction velocity, we conducted three regression analyses on these data: a "hockey stick" regression, a logistic regression, and a quadratic regression. We found evidence for a threshold in all three analyses: at a blood level of 30 micrograms/dL in the "hockey stick" regression, at 20 micrograms/dL in the logistic, and at 25 to 30 micrograms/dL in the quadratic. Neither age, sex, socioeconomic status, nor duration of residence near the smelter significantly modified the relationship. These analyses confirm that asymptomatic increased lead absorption causes slowing of nerve conduction, but they also indicate that measurement of maximal motor nerve conduction velocity is an insensitive screen for low-level lead toxicity.

Assessment of central and peripheral nerve functions in chain-saw operators: a study of short-latency somatosensory evoked potential and peripheral nerve conduction.

In order to clarify the effects of local vibration on the peripheral and central nervous system, peripheral (median) nerve conduction velocities and short-latency somatosensory evoked potentials (SSEP) following stimulation of the median nerve at the wrist were measured in 15 male forest workers in 1986. They had engaged in chain-saw operation for 16-34 (mean 22) years; their working days in 1985 averaged 124 days with a range of 50-203 days. The results indicated significant delays in maximal motor and sensory nerve conduction velocities followed by prolongation of all 4 peak latencies of SSEP up to the sensory cortex of the brain (N9, N13, N20 and P23 latencies) in chain-saw operators; their N9 and P23 latencies were significantly correlated with total working days per year. On the other hand, no significant prolongation of the interpeak latencies of SSEP (i.e., cervico-spinobulbar and central conduction times) was found in the workers. It is concluded that local vibration predominantly affects peripheral nerve conduction; cervico-spinobulbar and central nerve conduction may not be significantly affected.