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J A Nobrega

Publications and source records attributed to J A Nobrega.

10 recordsLinked to original sources
PubMed2001

A comparison between different parameters in F-wave studies.

Ulnar nerve F-waves were studied in 23 healthy volunteers and 27 diabetic patients. Latencies and chronodispersion were analyzed in each group. In the diabetic group all the parameters were normal in 14 patients (52%) and in 13 (48%) at least one parameter was altered. In these patients the most frequently altered parameter was the maximum latency (92%), followed by mean latency (85%), minimum latency (54%) and chronodispersion (54%). These findings suggest that maximum and mean latencies are better parameters to be analyzed in ulnar F-wave studies than minimum latency.

Adolescent↗
PubMed2001

[A review of technical and physiological aspects of F-wave studies and analysis of the data obtained in a group of diabetic patients].

We reviewed some physiological aspects of the F-wave studies, mainly related to the motoneurone sizes involved in the generation of this potentials and the number of stimuli necessary to analyze the F-wave parameters. F-wave latencies and F-wave conduction velocities obtained in a group of normal volunteers and in a group of diabetic patients are analyzed.

Adolescent↗
PubMed2000

F-waves and conduction velocities range.

A controversial aspect in F-wave studies is if these potentials are generated preferentially by large motoneuron or by motoneuron of all sizes. The purpose of this work is to compare the maximum and minimum conduction velocities of the fibers that generate the M-wave with the maximum and minimum conduction velocities of the F-waves elicited by ulnar nerve stimulation. There were no significant differences between maximum velocities. However, minimum F-wave velocity was significantly higher than minimum conduction velocity, suggesting that the F-waves registered were preferentially generated by the fastest conducting axons.

Adult↗
PubMed1999

Sample size and the study of F waves.

Ulnar nerve F waves were studied in 23 healthy volunteers and 27 diabetic patients. Latencies and chronodispersion were analyzed in each group for different sample sizes. Significant differences were not detected with the different sample sizes for mean latencies, with samples above 16 stimuli or 10 waves for minimum and maximum latencies and above 20 stimuli or 16 waves for chronodispersion. These findings suggest that these limits may be adequate for group comparison. However, for the analysis of individual patients, the evidence suggests that larger samples are required for the determination of the minimum and maximum latencies and chronodispersion.

Adolescent↗
PubMed1996

Facial nerve electroneurography. Variability in normal subjects.

Twenty normal individuals were submitted to facial nerve electroneurography using different techniques in order to determine the most accurate to obtain the latencies and amplitudes of the compound muscle action potentials (CMAP) of the facial muscles. First of all it was determined in which muscle or muscle group highest amplitude CMAP could be recorded with the lowest variability between sides and in test-retest. Different techniques were studied in order to determine which could give the best results. This was shown to be an arrangement of bipolar surface electrodes fixed to a plastic bar. The records with higher amplitude where obtained from the nasolabial fold muscles. Therefore 65 normal volunteers were examined using this technique and recording the potentials obtained over the nasolabial fold muscles. Normal values were determined (latency lower than 4.5 ms and amplitude larger than 2 mV--95% confidence limits).

Action Potentials↗
PubMed1996

Facial electroneurography in Bell's palsy. Variability in the early stage and comparison between interpretation methods.

To determine the variability of the abnormalities found in the electroneurography (ENG) of the facial nerve in cases of Bell's palsy during the initial two week period was one of the objectives of the authors. A second one was to investigate the value of ENG as a tool to determine an early prognosis of recovery utilizing two different methods. In the first one the amplitude of the compound muscular action potential (CMAP) obtained on the paralyzed side was compared to this potential on the opposite (normal) side. The second method compared the CMAP on the paralyzed side to normal standardized data from normal individuals. A group of 33 patients with Bell's palsy was followed until total recovery of for at least 4 months, if the recovery was not achieved earlier. It was observed that amplitude of the CMAP become stable towards the sixth day of palsy and this is a good time to establish the prognosis. Another conclusion is that both methods were equivalent to determine the prognosis in Bell's palsy.

Action Potentials↗
PubMed1978

[Vogt-Koyanagi-Harada syndrome: report of a case].

A case of Vogt-Koyanagi-Harada syndrome which had an ocular onset unilateral in the beginning and bilateral afterwards is reported. One month after the disease had appeared a psychiatric disturbance was detected characterized by mania and loss of the critical sense. The alterations detected in the eletroencephalograms and cerebrospinal fluid are discussed. After a three and a half years follow up, despite the corticotherapy the patient had a poor evolution on the ophtalmological aspect but the psychiatric recovery was total.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Nerve conduction study of the medial and lateral plantar nerves.

The medial and lateral plantar nerves may be evaluated through the recordings of the compound sensory nerve action potentials (CSNAP), compound mixed nerve action potentials (CMNAP) and compound muscular action potentials (CMAP). As some of these potentials are not easily and always obtainable in normal individuals, our purpose was to verify the consistency of these potentials for the study of these nerves. Fifty-one normal adult volunteers were examined. The CSNAP, CMNAP and CMAP, related to the medial and lateral plantar nerves were evaluated bilaterally. CSNAP were not obtained in 7.8% and in 17.6% from the medial and lateral plantar nerves respectively. CMNAP from the lateral plantar nerve were not obtained in 15.6%. CMNAP from the medial plantar nerves and CMAPs from the abductor hallucis and abductor digiti quinti were obtained for all nerves tested. Our results, therefore, suggest that these last 3 parameters are the ones more reliable for clinical application.

Action Potentials↗