New possibilities of improving the function of the hand of patients with spastic hemiplegia

The report presents a therapeutic proposal aiming at the improvement of the functions of the paretic hand in spastic hemiplegics. To achieve this aim the author suggests a combination of phenolization of the medial and ulnar nerves and the stimulation training of the wrist and fingers extensors. An implanted stimulator is used; the stimulator electrodes are fixed to the radial nerve. The strengthening of the extensors during the period of increased muscular tension of the flexors makes it possible to improve the functions of the paretic upper extremity.

Effects of transcutaneous electrical nerve stimulation and aspirin on late somatosensory evoked potentials in normal subjects

The effects on late somatosensory evoked potentials (SEPs) of transcutaneous nerve stimulation (TENS) and aspirin (600 mg), compared with placebo, were studied in 32 young, healthy male and female volunteers. SEPs were produced by electrical stimulation of the median nerve at moderate, non-painful, intensities. There was a reduction in the peak-to-peak amplitude of the late components N1P2 (N1 latency: 100-160 msec; P2 latency: 160-260 msec) of the SEP in all groups over time. TENS but not aspirin produced further significant changes compared with placebo, including a fall in N1P2 amplitude, an increase in N1 latency, and a decrease in the total excursion of the SEP between 25 and 450 msec after stimulus onset.

Prospective neurometric studies during the beginning of carbamazepine and phenytoin therapy

We studied 23 epileptic outpatients to assess carbamazepine and phenytoin therapy effects on the peripheral nerve conduction velocity, the electromyogram, and the EEG background activity. Immediately before and 3, 5, 11, 22 months after beginning treatment with 300-800 mg carbamazepine or 200-400 mg phenytoin, the patients were examined with electroneuromyographic and quantified EEG tests. Carbamazepine, phenytoin, folate, and vitamin B12 serum concentration were simultaneously monitored. Clinical signs of intoxication or polyneuropathy were not observed. The mean serum concentrations were 29 mumol/l for carbamazepine and 43 mumol/l for phenytoin. There was little evidence that anticonvulsants' serum concentration at these levels are related to changes in the electroneuromyographic tests or the alpha rhythm.

Local neurotoxicity of methyl methacrylate among dental technicians

Dental technicians often handle methyl methacrylate bare-handed before the polymerization reaction, and the monomer can penetrate the skin during the process. Nerve conduction velocities were determined in 20 dental technicians who had slight neurological complaints and in 18 healthy control persons. The motor and sensory conduction velocities in the forearm sections were normal and similar in both the study and the control group. Dental technicians had significantly slower distal sensory conduction velocities from the digits I, II and III on the right hand and also from the radial aspects of the digits II and III on the left hand than did the controls. Findings are considered to represent mild axonal degeneration on the areas with the closest and most frequent contact with methyl methacrylate.

Aldose reductase inhibition improves nerve conduction velocity in diabetic patients

To assess the potential role of polyol-pathway activity in diabetic neuropathy, we measured the effects of sorbinil--a potent inhibitor of the key polyol-pathway enzyme aldose reductase--on nerve conduction velocity in 39 stable diabetics in a randomized, double-blind, cross-over trial. During nine weeks of treatment with sorbinil (250 mg per day), nerve conduction velocity was greater than during a nine-week placebo period for all three nerves tested: the peroneal motor nerve (mean increase [+/- S.E.M.], 0.70 +/- 0.24 m per second, P less than 0.008), the median motor nerve (mean increase, 0.66 +/- 0.27, P less than 0.005), and the median sensory nerve (mean increase, 1.16 +/- 0.50, P less than 0.035). Conduction velocity for all three nerves declined significantly within three weeks after cessation of the drug. These effects of sorbinil were not related to glycemic control, which was constant during the study. Although the effect of sorbinil in improving nerve conduction velocity in diabetics was small, the findings suggest that polyol-pathway activity contributes to slowed nerve conduction in diabetics. The clinical applicability of these observations remains to be determined, but they encourage further exploration of this approach to the treatment or prevention of diabetic neuropathy.

[Electrophysiologic changes in thalidomide neuropathy in the treatment of discoid lupus erythematosus]

Twenty-six patients suffering from lupus erythematodes discoides were under clinical and electrophysiological examination. The results are in agreement with the concept of a mainly sensory, distal and axonal polyneuropathy. A correlation between total dosage and severeness of polyneuropathy could not be found.

Reversibility of neurological deficits in vitamin B12 deficiency

A female patient with subacute neurological deficits secondary to an hereditary vitamin B12 deficiency was repeatedly examined clinically and neurophysiologically. It is concluded that neurological normalization after treatment with vitamin B12 also occurs within the CNS. Such normalization takes place soon after initiating treatment and probably reflects other neuronal mechanisms that remyelination, i.e. recovery from conduction block in fast somatosensory pathways and/or improvement of synaptic transmission.

Evoked potential monitoring during acute occlusion of the basilar artery and selective local thrombolytic therapy

Neurophysiological examinations of brainstem functions before, during and after selective interventional neuroradiology i.e. selective intraarterial thrombolytic therapy of an acute occlusion of the basilar artery are reported. The success of the therapy was demonstrated by the reappearance of normal somatosensory potentials and of the blink reflex immediately after the thrombolysis. The BAEPs were continuously recorded during the thrombolysis. Normalization of the latencies and of the interpeak latencies at a very early stage of the therapy indicated the improvement of brainstem functions.

Peripheral motor neuropathy caused by excessive intake of dapsone (Avlosulfon)

A case of selective peripheral motor polyneuropathy caused by excessive intake of dapsone is described. The condition was characterized by a peripheral muscle weakness in all limbs, normal sensitivity and present, although weak, muscle reflexes. Neurophysiologically, low amplitude muscle responses, prolonged distal latencies and reduced motor conduction velocities were found together with electromyographic signs of denervation. Sensory neurography was normal. The patient showed a complete clinical recovery and a marked neurophysiological restitution after termination of the excessive drug intake. The patient was found to acetylate dapsone at a slow rate. The case is compared with those previously reported in the literature.

Misonidazole Neuropathy: a clinical, electrophysiological, and histological study

We studied eight patients with carcinoma of the pharynx and larynx (five cases) or lungs (three cases) who, during treatment with the radiosensitizing drug misonidazole, developed peripheral neuropathy dominated by severe sensory symptoms and signs mainly localized to the lower extremities. The symptoms partially subsided within months after cessation of therapy. Electrophysiological and histological findings indicated an axonal neuropathy with loss of large fibers and secondary demyelination. The neurotoxic property of misonidazole limits its therapeutic use.

Electromyographic study of diabetic and alcoholic polyneuropathic patients treated with gangliosides

A double-blind, randomized electromyographic investigation was conducted of the effects of cerebral ganglioside treatment on patients suffering from diabetic or alcoholic polyneuropathy. Cerebral gangliosides (50 mg once a day) administered to 15 diabetic and to 15 alcoholic neuropathic patients for 40 days, facilitated the reappearance of sensory potentials and significantly increased the MAP amplitude in median, ulnar, and peroneal nerves. In relation to ganglioside treatment, there was no significant change in the conduction velocities or in the distal latencies of these nerves, nor was there a change in the duration of the MAPs. On the basis of these results, it is suggested that the cerebral gangliosides are capable of inducing an improvement in the excitability of nerve fibers and of facilitating the processes of reinnervation, probably by means of an enhancement of fiber sprouting.

[Effects of muscle relaxant E.M.P.P. on afferent discharges of muscle spindle in man--an microneurographic analysis (author's transl)]

Effects of a new muscle relaxant E.M.P.P.(4'-ethyl-2-methyl-3-piperidino-propiophenone . hydrochloride) on afferent discharges of muscle spindle were studied in 10 healthy volunteer subjects. Single unit afferent discharges of muscle spindle were recorded microneurographically from the median or tibial nerve using a tungsten microelectrode with a tip diameter of about 1 micrometer (impedence: about 10 M omega). Effects of an oral administration of 150--300 mg of E.M.P.P. on spontaneous afferent discharges as well as dynamic and static responses of muscle spindle were analysed in the present study. 1. E.M.P.P. suppressed remarkably the frequency of spontaneous afferent discharges of muscle spindle. Meanwhile, mental activations such as speech of mental arithmetic recovered temporarily the frequency of afferent discharges to that before E.M.P.P. administration. 2. E.M.P.P. suppressed the dynamic and static responses of muscle spindle to stretch. It also suppressed the dynamic responses of muscle spindle in the decontraction phase of electrically-induced twitch contractions of the receptor-bearing muscle. Based on these results, it is concluded that E.M.P.P. suppresses the static and dynamic activities of muscle spindle in man. These effects seem to be due to modifications of descending influences from central structures on the static and dynamic gamma motoneurons which innervate the muscle spindle.

Bromocriptine for an acromegalic patient. Improvement in cardiac function and carpal tunnel syndrome

A 64-year-old woman with active acromegaly of 33 years' duration, severe carpal tunnel syndrome, and subclinical heart disease was treated with bromocriptine mesylate. Within eight months of therapy, basal growth hormone (GH) levels decreased from 90.0 to 7.0 ng/mL, and hand volume was reduced from 375 to 295 mL. Concomitantly, echocardiographic studies showed normal left ventricular size and function. Electromyographic studies demonstrated normal function in both median nerves. Bromocriptine may correct cardiac dysfunction and carpal tunnel syndrome in acromegaly either by reduction of GH oversecretion or by a direct effect of bromocriptine on dopamine receptors in the heart and peripheral nerve endings.

Nitrous oxide neurotoxicity studies in man and rat

To assess the effects of chronic exposure to low levels of nitrous oxide on neural function of man, the authors evaluated the neurologic condition, motor and sensory nerve conduction, and computerized tests of sensation of approximately half of the dentists in Rochester, Minnesota. Results of scored tests of neural function were not significantly different for dentists who used nitrous oxide extensively in their practices and dentists who did not. To assess the effects of chronic exposure to high levels of nitrous oxide on neural function and structure of experimental animals, groups of rats were exposed to 70 per cent N2O in 30 per cent oxygen for four hours, five days a week, for six months. Rats exposed to N2O and control rats showed no difference in well-being, in caudal nerve conduction, in axonal content and transport of acetylcholinesterase and dopamine-beta-hydroxylase, or in number and size distribution and pathologic abnormality of teased myelinated fibers. Although these results indicate a lack of peripheral nerve neurotoxicity of N2O in the rat, one cannot assume a similar lack of neurotoxicity in man with heavy exposures.

The importance of studying sural nerve conduction and late responses in the evaluation of alcoholic subjects

Motor conduction velocities of median, ulnar, peroneal, and tibial nerves and sensory conduction velocities of median and ulnar nerves were studied in 30 alcoholic subjects and a similar group of control subjects. The results were compared to sural nerve conduction velocities and late response latencies (H reflex, F response). The latter two techniques improved the diagnostic yield by 20%: Whereas 73% of our patients showed an abnormality of conduction with conventional techniques, 93% had an abnormality of sural nerve conduction, late response latencies, or both. Abnormalities of motor and sensory conduction, which were more prominent in the lower limbs than the arms, could be documented in patients who did not have any clinical evidence of peripheral neuropathy. The electrophysiologic studies performed in the present study suggest that "axonal degeneration" is the underlying pathologic process in alcoholic peripheral nerve disease.

Peripheral electrophysiological parameters in mice treated with misonidazole

The clinical use of the radiosensitizer misonidazole may be limited by the incidence of peripheral neuropathy reported following total doses in excess of 18 g. A recent report noted a decrease in nerve conduction velocity following a single i.p. injection of 1 mg/g misonidazole in mice. The present study was unable to confirm such changes when nerve conduction velocity measurements were made in situ or in isolated sural, tibial or median nerves of mice. Other electrophysiological parameters such as threshold, strength-duration curves, refractory time or the ability to carry high-frequency stimulation also showed no change. However, it was noted that a single administration of the radio-sensitizer produced a marked decrease in body temperature which persisted for at least 2 h after the elimination of the drug from the blood serum. The physiological response of reduction of body temperature may protect the mouse against the effect of the toxic chemical species involved in the induction of neurotoxicity.

Nerve fibre refractory period in patients treated with rubidium and lithium

Nerve fibre refractory period distributions have been measured on the median nerves of six manic-depressive patients controlled with lithium carbonate, three chronic patients (two manic-depressives and one catatonic schizophrenic) controlled with rubidium chloride, and eight normal volunteers. Rubidium prolonged the refractory periods of all nerve fibres while lithium increased only the longer refractory periods.

A teased-fibre study of the median nerves of vitamin B12-depleted baboons

Isolated nerve fibres of the median nerve of normal baboons and baboons kept on diets deficient in vitamin B12, and supplemented with potassium cyanide and potassium thiocyanate injections, were examined by the teased-fibre technique. Regression lines of internodal length on fibre diameter were obtained. Small differences between the groups were apparent but were of uncertain significance. There was occasional evidence of segmental demyelination and Wallerian degeneration but this was not characteristic of any particular group.

[Polyneuropathy caused by tuberculostatics. Study of motor nerve conduction in 29 patients]

The electroneurographic study in 29 patients, during treatment with isoniazid for pulmonary tuberculosis in 12 months period is reported. The patients age were between 16 and 70 years. During the study period motor nerve conduction velocity was done every two months in the median, ulnar and peroneal nerves. The statistical analysis in a 6 months period, revealed p greater than 0.05 (nonsignificant) at the median and peroneal nerves, in spite of the lowering of the motor nerve conduction in a 12 months period. The same findings were observed with the ulnar nerve, but p less than 0.01 (significant). It was impossible to establish a correlation between the motor nerve conduction velocities and the clinical findings observed in the patients. This paper, in the author's opinion, shows that the nerve motor conduction technique is worthless in the follow up of isoniazid patients.

Neuromuscular block after intra-arterially injected acetylcholine. 2. Effects of ACTH treatments as possible detectors of desensitization level in the receptor site

It has been suggested that the effect of ACTH in myasthenia gravis may be ascribed to an action involving neuromuscular transmission which favours repolarization processes, with a tendency towards hyperpolarization of the membranes of muscle fibres and motor nerve endings. A similar mechanism has been postulated for the action of ACTH in epilepsy (Klein, 1970). A direct or indirect action on nerve membrane would interfere with depolarization. There is evidence of raised concentration of intracellular potassium and increased outflow of sodium ions which would cause hyperpolarization of the membrane. This paper studies the effect of ACTH on the late block of neuromuscular transmission caused by acetylcholine (ACTH).

Sensory and motor nerve conduction velocity in long-term diphenylhydantoin therapy

Eleven epileptic patients under long-term DPH therapeutical doses were studied and the obtained results allow us to postulate that DPH, when is administrated for long periods, can produce damage of the peripheral nerve by involvement of the sensory and motor fibres in a similar degree.

Vincristine neuropathy: an electrophysiological and histological study

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