ABSTRACT
We studied inhibition of median nerve H-reflex produced by radial nerve stimulation in both arms of 14 patients with hand cramps and 15 normal volunteers. Median nerve stimulation was delivered 1 and 0.5 msec before and 0, 0.5, 1, 2, 10, 20, 30, 50, 75, 100, 200, 500, and 1,000 msec after radial nerve stimulation. Recordings were from surface electrodes positioned over flexor carpi radialis. We identified three periods of attenuation of median nerve H-reflex amplitude in the control group. When radial nerve conditioning stimuli were delivered simultaneously, 10 and 75 msec before median nerve test stimuli, H-reflex amplitude diminished to 47%, 61%, and 69%. In the patient group we also found three periods of attenuation at the same delays, but the amount of attenuation was significantly less than in controls. Dividing the patients into two groups, dystonic hand cramp and simple hand cramp, both showed less inhibition than the control group, but the abnormality was greater in the dystonic cramp group. This test is the first to demonstrate physiologic disturbance in patients with hand cramps.
Subject(s)
Hand , Muscle Cramp/etiology , Neural Inhibition , Adult , Analysis of Variance , Dystonia/physiopathology , Electric Stimulation , H-Reflex , Humans , Median Nerve/physiopathology , Middle Aged , Muscle Cramp/physiopathology , Reaction Time , Reference ValuesABSTRACT
A group of patients with Bell's palsy were studied in order to disclose the presence of subclinical peripheral nerve involvement. 20 patients, 8 male and 12 female, with recent Bell's palsy as their unique disease were examined. In all cases other causes of polyneuropathy were ruled out. Patients were investigated with CSF examination, facial nerve latencies in the affected and in the sound sides, and maximal motor nerve conduction velocities, as well as motor terminal latencies from the right median and peroneal nerves. CSF laboratory examination was normal in all cases. Facial nerve latencies were abnormal in all patients in the affected side, and they differed significantly from those of control group in the clinically sound side. Half of the patients showed abnormal values in the maximal motor nerve conduction velocities and motor terminal latencies of the right median and peroneal nerves. These results agree with previous reports which have pointed out that other cranial nerves may be affected in Bell's palsy. However, we have found a higher frequency of peripheral nerve involvement in this entity. These findings, support the hypothesis that in some patients Bell's palsy is the component of a more widespread disease, affecting other cranial and peripheral nerves.
Subject(s)
Facial Paralysis/physiopathology , Neural Conduction , Peripheral Nerves/physiopathology , Adolescent , Adult , Aged , Facial Nerve/physiopathology , Female , Humans , Male , Median Nerve/physiopathology , Middle Aged , Peroneal Nerve/physiopathology , PrognosisABSTRACT
Um grupo de pacientes com paralisia de Bell foi estudado com o objetivo de descobrir a presenca de comprometimento nervoso periferico subclinico. 20 pacientes, 8 homens e 12 mulheres com paralisia de Bell recente como unica enfermidade, foram examinados. Em todos os casos outras causas de polineuropatia foram excluidas. Os pacientes foram estudados com exames de liquido cefalorraqueano; latencia distal nos nervos faciais do lado afetado e do lado sadio e velocidade de conducao motora maxima; latencia distal dos nervos mediano e peroneiro direitos.O exame de LCR foi normal em todos os casos. A latencia do nervo facial foi anormal em todos os pacientes no lado afetado e, no lado clinicamente sadio, diferia significativamente do grupo controle. A metade dos pacientes mostrou valores anormais na velocidade motora maxima e/ou na lactancia distal de ambos os nervos, como sejam: mediano e peroneiro.Esses resultados estao de acordo com publicacoes anteriores nas quais se afirma que outros nervos craneanos podem estar afetados na paralisia de Bell. Temos encontrado uma elevada frequencia de polineuropatia nesta enfermidade. Estes achados nos levam a crer que, em alguns enfermos a paralisia de Bell e um componente de uma doenca mais disseminada afetando outros nervos craneanos e perifericos
Subject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Facial Paralysis , Neural Conduction , Peripheral NervesABSTRACT
In a group of patients chronically denervated and other with primary muscle involvement a search was made for mechanisms involved in the muscular fatigue. It was found that there was no major differences between patients chronically denervated and controls, while in those others with primary muscle disorders a loss of functional motor units during effort and a transient impairment of neuromuscular transmission play a role together with the central events normally occurring in fatigue.
Subject(s)
Muscles/physiopathology , Neuromuscular Diseases/physiopathology , Peripheral Nervous System Diseases/physiopathology , Action Potentials , Electromyography , Female , Humans , Male , Motor Neurons/physiopathologyABSTRACT
Muscular fatigue was investigated in 13 healthy people by employing a simple device which comprises a computer on line with a conventional EMG equipment able to automatically measure the frequency and duration of free-run EMG recording. The procedure was carried out in the extensor digitorum brevis muscle by using surface electrodes throughout 10 minutes of voluntary maximal effort. The maximal M wave as well as the muscle response to repetitive nerve maximal stimulation was also explored at the beginning and at the end of the experiment. It was observed a decrease of the potentials frequency discharge and an increase of their duration without major changes in the M wave amplitude neither in the muscle response to the repetitive nerve discharge. The findings pointed out to the central factors as the mean responsible for the development of muscular fatigue.
Subject(s)
Electromyography , Muscle Contraction , Muscles/physiology , Physical Exertion , Action Potentials , Adult , Electric Stimulation , Female , Humans , Male , Motor Neurons/physiologyABSTRACT
Muscular fatigue mechanisms were partially analyzed in patients with pyramidal lesions by using a computer device on line with a conventional electromyograph. Both the normal and the affected side were compared with control groups. The recordings were done throughout a ten minutes period and the maximal M wave was also measured at the starting and at the end of the procedure. The findings suggested that central events play a major role in the development of muscular fatigue in spastic muscles due to pyramidal damage.
Subject(s)
Electromyography , Hemiplegia/physiopathology , Muscles/physiopathology , Pyramidal Tracts/physiopathology , Action Potentials , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Motor Neurons/physiologyABSTRACT
Se estudio la fatiga muscular en 13 normales; para ello, fueron sometidos a un esfuerzo sostenido durante 10 minutos previo y posterior, al cual se realizo la medicion de la onda M maxima. Durante el esfuerzo y cada 2 minutos, se obtuvieron cuantificaciones de la frecuencia y duracion de las ondas positivas y negativas del EMG. Los resultados, mostraron diferencias significativas de estos valores, en funcion del tiempo de esfuerzo realizado, mientras que las mediciones de la onda M maxima incial y final, no fueron diferentes, todo lo cual lleva a jerarquizar el factor central como el mas importante en el desarollo de fatiga, bajo nuestras condiciones de estudio, que son ademas de sencilla aplicacion clinica
Subject(s)
Adult , Humans , Male , Female , Electromyography , Exercise , Muscle Contraction , MusclesABSTRACT
Para evaluar algunos de los componentes de la fatiga muscular en el dano piramidal, se selecciono un grupo de 15 pacientes con hemiparesia faciobraquiocrural de severidad variable, los cuales fueron sometidos a un esfuerzo muscular, durante el cual se evaluaron los cambios de la frecuencia y duracion de los potenciales positivos y negativos de EMG, asi como los sufridos por la onda paretico, el contralateral y en un grupo control de voluntarios sanos, comparandose los resultados de los 3 grupos. Las curvas de frecuencia y duracion del labo paretico, el sano y el control mantuvieron las mismas tendencias, asi como fue homologable el comportamiento de la onda M maxima en los 3 casos, lo cual indica que en la poblacion normal, bajo las presentes condiciones de estudio, es el factor central el condicionante principal en el desarrollo de fatiga muscular
Subject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Electromyography , Exercise , Hemiplegia , Muscles , Pyramidal TractsABSTRACT
Utilizando un metodo de cuantificacion del electromiograma, se investigaron parte de los mecanismos centrales y perifericos responsables de la fatiga muscular en enfermos cronicamente denervados y en pacientes con compromiso muscular primitivo.Se observo en los denervados que los mecanismos de fatiga muscular, no difieren mayormiente de los observados en el grupo de sujetos sanos, por el contrario, en los miopaticos a mas del componente central, tales como la perdida de unidades motoras funcionantes durante el esfuerzo y el bloqueo temporario de la transmision neuromuscular, que contribuye al desarrollo de la fatiga
