Biomedical subjects
Publications and source records attributed to B Fierro.
We report the case of a 24 year old woman who developed myasthenia gravis in the course of a mild form of Charcot-Marie-Tooth neuropathy. We describe the clinical manifestations together with the neurophysiological, pathological, serological findings and response to therapy and discuss the unusual association in the light of the relevant literature.
Brainstem auditory evoked potentials (BAEPs) were evaluated in three patients with mitochondrial encephalomyopathy belonging to the same family. This study showed marked alterations of BAEPs in all patients: reduction of wave amplitude, poor repeatability of responses in test-retest and abnormalities in wave form and latency. The neuroradiological examinations (CT-scan, MRI) did not show significant structural brain abnormalities. Abnormal BAEPs in our patients may be related to central metabolic disorder rather than hearing loss.
A case presenting with clinical features of ocular myasthenia and a false-positive edrophonium test is reported. Brain CT and MRI scan revealed a pineal region tumor histologically verified as germinoma. We recommend evaluating patients with clinical features of myasthenia gravis (MG) confined to the ocular muscles for intracranial mass lesions.
There is evidence from several laboratories of an increased prevalence of circulating immuno-complexes (CIC) in diabetic patients. It has also been suggested that CIC are pathogenetically related to chronic diabetic complications. The aim of this study was to assess peripheral nerve function in children with Type 1 diabetes and to evaluate the relationship between the neurophysiological abnormalities and the possible presence of CIC. The investigation was carried out in 25 Type 1 diabetic patients ranging in age from 7-19 years and in 20 normal controls. Neurophysiological assessment was performed to evaluate motor and sensory conduction velocity on median and tibial nerves. IgG-CIC were detected by the solid-phase C1q-binding and anti-C3 enzyme immuno-assay. The results of this study showed a greater slowing of median motor and sensory and tibial sensory conduction velocities in patients with CIC with respect to the patients without CIC, suggesting a possible role of immunological factors in the pathogenesis of diabetic neuropathy.
A retrospective case-control study was conducted to estimate the possible association between risk of multiple sclerosis (MS) and the number of changes in residence before the age 20 years. Forty-one patients and 82 controls were interviewed. Using the Mantel-Haenszel estimate of the odds ratio, no association was found between the number of moves and MS.
A retrospective case-control study was conducted using 46 patients affected by amyotrophic lateral sclerosis and 92 closely matched healthy controls. Cases were ascertained through typical clinical and instrumental findings. Putative risk factors (bone fractures or major trauma, exposure to domestic animals, surgical operations, disease among first degree relatives and others) were investigated anamnestically using a standard questionnaire. Using Mantel-Haenzsel estimates of the odds ratio, no association was found between amyotrophic lateral sclerosis and the investigated variables.
In 50 ulnar nerves of healthy subjects, F-wave latency, duration, amplitude and persistence were determined at different frequencies of the antidromic impulse (0.2-0.5-1-2 Hz). The F amplitude and persistence were found significantly increased at higher stimulation rates, suggesting that the frequency of the antidromic impulse influences the motoneuron pool discharges. Individual cross-correlation values (r) obtained for latency and duration, latency and amplitude, amplitude and duration did not show any significant changes at different stimulation rates.
The F response can provide a measure of motoneurone excitability (MNE) and so it may be used to investigate upper motoneurone disorders. This report studies the F-wave configuration in patients with stroke to evaluate the changes of the central excitability of the motoneurones at different times after an acute cerebral insult. Various parameters of the F response, including amplitude (absolute and F%/M), duration, and persistence have been determined in 26 patients with unilateral hemiplegia and in 32 healthy subjects of both sexes in the same age range. The investigation was carried out applying a series of 20 supramaximal stimuli at 0.5 Hz on tibial and ulnar nerves bilaterally. In all patients a detailed clinical examination and a CT scan were performed. Our results indicate that an initial stage of reduced spinal motoneuron excitability evidenced by a decreased F amplitude and persistence was present in the early phases after a stroke, followed within 90 days by an enhanced MNE. Moreover, F-wave amplitude shows a positive correlation with weakness and increased tone.
Various parameters of the F-response (latencies, chronodispersion, amplitude, duration, shape, persistence) were investigated in ulnar and tibial nerves of 50 healthy subjects of both sexes, aged between 16 to 79 years. The observations were made bilaterally and the results revealed no significant differences in any of the F-parameters by comparing side to side. The relationships between each neurophysiological F-response data and limb length, age and sex of control subjects were determined. Correlations of high statistical significance were found between minimum F-latency and limb length as well as between absolute and F%/M-amplitude and age. Cross-correlation coefficients correlating mean individual values of latency-duration, latency-amplitude and amplitude-duration did not show any significant relationship between latency, amplitude and duration in normal subjects.
The incidence, prevalence and natural course of ALS were determined in the population of the province of Palmero, Italy. The average annual incidence calculated for the years 1973 through 1984, was 044./100.000 inhabitants. The prevalence rate on prevalence day December 31, 1984, was 1.67/100.000 population. The male/female ratio was 1.38. The mean age at onset was 54.3 +/- 11.02. The most common clinical form was the conventional one (61.4%); the bulbar form was more frequent among females than males. The mean duration of the disease was 33.7 +/- 35.8 months. The longest duration belongs to the pseudopolyneuritic form. The median survival was 36 months: 16 months for the bulbar, 36 months for the conventional and 51 months for the pseudopolyneuritic form.
The role of metabolic abnormalities in the development of diabetic neuropathy is controversial. To investigate the peripheral nerve function and the influence of hyperglycemia on nerve conduction in insulin-dependent diabetes, a one-year neurophysiological study was carried out in 30 type 1 diabetic patients ranging in age from 2-16 years. During the 12-month follow-up period the glycosylated hemoglobin determination, motor conduction velocity of the peroneal nerve and the motor and sensory conduction of the tibial nerve were assessed 3 times, at the beginning of the study and every 6 months thereafter. The sensory latency was found significantly delayed in these patients as compared with the controls. The degree of sensory conduction slowing correlated well with the glycosylated hemoglobin concentrations and improved with the reduction in hyperglycemia.
The ulnar and tibial nerve F response latencies were analyzed to study the proximal motor conduction velocity in 15 patients with liver disease. The results were compared with those obtained from 15 normal subjects. The tibial MNCV (P less than 0.01) and FWCV from spinal cord to elbow and knee for ulnar and tibial nerves (P less than 0.001) were significantly reduced in patients compared to the controls. Minimum, mean and maximum F latencies showed significant differences for ulnar (P less than 0.001) and tibial (P less than 0.01) nerves in patients with respect to the controls. The mean F determination compared to the minimum F and delta F did not improve disease identification. The conduction abnormality in hepatic patients appeared to be present only in the proximal segment of the ulnar nerve, whereas it was more uniformly distributed along the entire length of the tibial nerve. This demonstrates that the peripheral nerve involvement in hepatic disease is more diffusely present than can be determined by conventional conduction study only.
The case of a myasthenia-like syndrome induced by cardiovascular drugs is reported. The clinical and electrophysiological features of the case are discussed.
Motor nerve conduction study along the entire length of the ulnar and tibialis posterior nerves was carried out in 30 diabetics compared with 30 uremic patients and 30 control subjects. The conduction in the proximal and the distal nerve segments was evaluated by the determination of the M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites), and F-ratio (conduction time ratio of proximal to distal segment). In both groups of patients the lower limbs appear much more involved than the upper, where the ulnar nerve is more commonly affected in uremic than in diabetic patients. In diabetic neuropathy the motor conduction abnormalities are diffuse over the total length of the nerve, but more marked distally in the ulnar nerve.
A clinical and electrophysiological study was carried out on 19 selected patients with chronic liver disease. Clinical signs of peripheral nerve involvement were found in 4 patients (21%); while electrophysiological impairment was present in 11 patients (57.8%). These abnormalities were mostly limited to the sensory and motor fibers of the tibialis posterior nerve. Our data confirm the presence of peripheral nerve involvement in chronic liver disease, and that it may be evidenced by careful electrophysiological examination.
Motor nerve conduction along the entire length of ulnar and tibialis posterior nerves was studied in 30 uraemic patients and in 20 control subjects. The M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites) and F-ratio (conduction time ratio of proximal to distal segment) were assessed to evaluate the conduction in the proximal versus the distal nerve segment. In the uraemic patients, the slowing of nerve conduction involved both segments of the tested nerves to the same extent. In fact, the F-ratio did not show any significant difference between the two groups; in only one patient was its value lower than the normal limit in the tibialis posterior nerve.
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Altitudinal hemianopias may be related to chiasmatic involvement. A case in which horizontal inferior hemianopia is associated with a tumor in the posterior fossa producing a triventricular hydrocephalus is described. The visual field defect is interpreted as a consequence of the pressure by a dilated third ventricle upon the chiasmatic area.