Nerve Conduction Velocity In Patients Research Articles

Correlates of delayed motor nerve conduction and retinopathy in juvenile-onset diabetes mellitus

Using a protocol designed to eliminate observer bias, we studied the relationship of duration of diabetes, age, blood glucose control, and the presence of retinopathy to motor nerve conduction velocity in patients with juvenile-onset diabetes of short duration. Conduction velocities for both the ulnar and peroneal nerves were significantly slower in the diabetic subjects than in the controls. Duration of diabetes, age, and diabetes control each had significant and independent effects on the prevalence of delayed conduction. Delayed conduction was present in more than 20% of those with diabetes of less than five years' duration, whereas retinopathy was present in none of our subjects with diabetes of the same duration. Moreover, although the presence of retinopathy was closely correlated with the presence of delayed conduction velocity, a number of diabetic subjects had one abnormality but not the other. We believe that delayed nerve conduction and retinopathy in diabetic patients are caused by multifactorial mechanisms that share a common relationship to duration, age, and degree of hyperglycemia, but which differ in at least some fundamental aspects.

Vitamin B12 levels and nerve conduction velocities in patients undergoing maintenance hemodialysis

Serum vitamin B12 concentrations were measured in 60 patients undergoing repetitive hemodialysis and in undialyzed patients with chronic renal failure. Dialysis patients had significantly lower serum vitamin B12 levels than the nondialyzed group 321 +/- SEM 38 pg/ml versus 793 +/- 100), and 19 of 60 dialysis patients had vitamin B12 Concentrations less than 200 pg/ml. Folic acid concentration was 5 times greater in dialysis than in nondialysis patients, presumably because the latter received daily supplementation with folic acid. Serum vitamin B12 concentrations fell progressively during the patient's course of dialysis. Neither inadequate dietary intake nor vitamin B12 malabsorption accounted for the differences in the serum vitamin B12 concentrations seen in the two groups. Serum vitamin B12 levels and nerve conduction velocities in 51 dialyzed patients showed a significant correlation. Six dialyzed patients with low serum vitamin B12 levels and slow nerve conduction velocities showed improvement in nerve conduction (+ 14.6 +/- 3.3 m/sec) following the parenteral use of pharmacological doses of vitamin B12. The cause of the low serum vitamin B12 concentration is not clear, nevertheless, alterations in serum vitamin B12 seen in some dialysis patients may be a factor in the persistence of abnormal nerve conduction and may be reversed with large doses of parenteral vitamin B12.

Nerve conduction velocity in patients on long-term diphenylhydantoin therapy.

SummaryMotor conduction velocities along the median, ulnar, peroneal, and posterior tibial nerves and distal sensory latency of the median nerve were determined in 300 patients on diphenylhydantoin therapy who did not present clinical evidence of either peripheral neuropathy or toxicity. Slowed conduction was found in 156 patients (52%). Most frequent were prolonged sensory latency of the median nerve (44%) and motor conduction in the legs (33%). Abnormal findings were more frequent in patients over 20 yr of age, when the dose was 4.5 mg/kg or more and the duration of medication 4 yr or more.ResuméChez 300 patients traités par la diphénylhydantoïhe et ne présentant aucun signe clinique de neuropathie périphérique ou d'intoxication, on a mesuré la vitesse de conduction motrice des nerfs médian, cubital, péronier et tibial postérieur, ainsi que la latence sensitive distale du nerf médian. Chez 156 patients (52%) la vitesse de conduction était ralentie. On a trouvé le plus souvent un allongement de la latence sensitive du médian (44%) et une diminution de la vitesse de conduction motrice au niveau des jambes (33%). Les valeurs anormales étaient plus fréquentes chez les malades âgés de plus de 20 ans quand la dose de diphénylhydantoïhe était de 4.5 mg/kg au plus et que le traitement durait depuis 4 ans ou plus.ZusammenfassungBei 300 mit Diphenylhydantoin behandelten Patienten, die keine klinischen Symptome einer peripheren Neuropathie oder von Toxizität zeigten, wurde die Nervenleitgeschwindigkeit des Nervus medianus, Ulnaris, Peronaeus und des Nervus tibialis posterior und zudem die distale sensorische Latenz des Nervus medianus bestimmt. Bei 156 Patienten, entsprechend 52%, war die NLG verlangsamt. Am haufigsten war die sensorische Latenz des Nervus medianus (44%) und die motorische Nervenleitgeschwindigkeit in den Beinen (bei einem Drittel) verlängert. Anormale Befunde waren häufiger bei Patienten über 20 Jahren, bei einer Dosierung von 4.5 mg pro kg Körpergewicht oder mehr und bei Behandlungszeiten von 4 oder mehr Jahren.ResumenSe determineó la velocidad de conducción motora de los nervios mediano, ulnar, peroneal y tibial posterior, así como la latencia sensorial distal del mediano en 300 pacientes que se encontraban en tratamiento con Difenilhidantoina y que no presentaban evidencia de neuropatía periférica o de intoxicación. En 156 pacientes (52%) se eonstató disminución de la conducción nerviosa. El hallazgo más frecuente fué el aumento de la latencia sensorial del n. mediano (44%) y una disminución de la velocidad de conducción motora en las piernas (33%). Los hallazgos anormales fueron más frecuentes en pacientes mayores de 20 años, cuando la dosificación era superior a 4.5 mg/kg de peso, y cuando la duración del tratamiento fué mayor de 4 años.

Neurological disorders and adult coeliac disease.

An investigation into the incidence of neurological disorder in 30 patients with adult coeliac disease has shown that three patients had severe depression, two had epileptiform convulsions, and one patient only had signs of involvement of the peripheral nervous system. Motor nerve conduction velocity was low in only one patient. When the nerve conduction velocities of the group on a gluten-free diet were compared with the group who were not on a gluten-free diet, there was no statistically significant difference. Similarly, nerve conduction velocities in patients with a low serum pyridoxal level were not significantly different from those with normal serum pyridoxal levels. Measurements of the serum level of pyridoxal in 30 patients confirmed that pyridoxine deficiency occurs in adult coeliac disease and that the restriction of gluten from the diet appeared to affect pyridoxal levels favourably.