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Biomedical subjects

M T Ferrer

Publications and source records attributed to M T Ferrer.

At least 19 recordsLinked to original sources
PubMed1991

Cardiovascular responses to tilting in healthy and diabetic subjects.

Cardiovascular responses to tilting from supine to upright and back to supine were investigated by measuring heart rate (HR) and blood pressure (BP) continuously by non-invasive methods. Subjects were 20 healthy controls, 17 diabetic patients (DN) with normal test results for parasympathetic cardiac function and 21 diabetics (DA) with abnormal results. In control subjects, tilting up and tilting back maneuvers induced opposite changes in HR, systolic (SBP) and diastolic BP (DBP). The most obvious responses appeared during the first 30 sec after either maneuver. The best measurements to detect sympathetic vasoconstrictor abnormalities during tilting up were derived from the recovery curve that followed the immediate fall in SBP, abnormal in 6 DN and 14 DA patients, and from the increase in DBP after the maneuver, abnormal in 7 and 16, respectively. Tilting back induced comparatively larger cardiovascular responses. The SBP remained stable after 10 sec in the controls, but increased above normal limits in 7 DN and 20 DA patients. The DBP fell during the first 10 sec in controls, but not in 4 DN and 17 DA patients. Continuous monitoring of BP during tilting is a more sensitive test of autonomic function than classical BP measurements made at a few selected intervals. The results challenge the view that parasympathetic dysfunction precedes and occurs more frequently than sympathetic dysfunction.

Adult↗
PubMed1991

Baroreflexes in patients with diabetes mellitus.

We evaluated baroreflexes in 58 diabetic and 15 control subjects by determining the latency of response between the end of a Valsalva maneuver (VM) and points on the resultant blood pressure and heart rate (HR) response curves. Prolonged latencies indicative of sympathetic dysfunction were demonstrated in 44% to 88% of diabetic subjects. The results challenge the view that sympathetic dysfunction cannot be detected before parasympathetic abnormalities are manifest. Baroreflex latencies reflected sympathetic dysfunction early in the course of diabetes, sometimes in patients with normal HR responses to deep breathing and to a VM.

Adult↗
PubMed1985

Electrophysiologic study in benign human botulism type B.

Conventional electromyography (EMG) and single fiber EMG (SFEMG) were performed in a 64-year-old diabetic woman with mild type B botulism. The main clinical signs were autonomic dysfunction and cranial nerves paresis. Conventional EMG was normal, except for small changes that were consistent with mild mixed peripheral neuropathy in the lower limbs and were related to diabetes. Repetitive stimulation and results of single stimulus before and after full effort were normal. SFEMG showed increased jitter and impulse blocking in clinically normal muscles. The jitter was frequency dependent and improved at a higher innervation rate. Impulse blocking in potentials with only slightly increased jitter was found. The follow-up showed improvement of the jitter in agreement with clinical recovery. Jitter abnormalities were recorded after 16 weeks, when clinical signs of botulism had been reversed to normal. Motor unit fiber density increased progressively, and on examination at 8 weeks, some potentials showed very high jitter values. Both findings might suggest new endplate formation, perhaps due to ultraterminal sprouting development.

Botulism↗
PubMed1984

Neuromuscular disorders in a new toxic syndrome: electrophysiological study--a preliminary report.

The electrophysiological features in 145 patients with a new toxic syndrome related to ingestion of adulterated oil are described. Myalgia, joint limitation, weight loss, cramps, progressive weakness and wasting, sensory disturbances that can be asymmetrical or patchy, and scleroderma-like changes were the main clinical features. The electrophysiological findings suggest that the neuromuscular impairment in the new toxic syndrome is a slowly progressive mixed axonal neuropathy, which starts asymmetrically in some patients, with involvement of proximal and distal muscles as well as paraspinal and respiratory muscles. Muscle and nerve biopsies confirm the neuropathy, and show severe perineuritis and perineurial and perimysial fibrosis. The single fiber electromyography (SFEMG) study showed increased motor unit fiber density directly related to the time after onset of the illness. Unstable complex potentials were found after 6 months of evolution, which suggests that an effective collateral reinnervation was delayed following a long period of progressive denervation.

Adolescent↗
PubMed1984

Bilateral carpal tunnel in childhood associated with Schwartz-Jampel syndrome.

The case of a 7-year-old girl, the only descendant of non-consanguineous parents, who presented typical features of the Schwartz-Jampel syndrome and electrophysiological evidence of bilateral carpal tunnel is reported. Conventional electromyogram (EMG) showed persistent and continuous electrical activity and high frequency discharges elicited spontaneously by movement of the needle or after voluntary activation. Electrical silence after phenytoin therapy was sometimes seen. Single fiber electromyography (SFEMG) showed that high frequency discharges had a complex configuration and multiple components. Occasionally the discharges showed a progressive decrease in amplitude. Increased jitter was also found in some potential pairs that had been isolated under voluntary contraction after phenytoin therapy. Motor and sensory conduction velocities on the median nerve were slowed bilaterally across the carpal tunnel. Bilateral carpal tunnel syndrome is an unusual condition in children and its clinical picture differs from that in adults. Carpal tunnel syndrome was not clinically suspected in the patient reported in this article and the diagnosis was confirmed by the conduction velocity study.

Abnormalities, Multiple↗
PubMed1983

Chronic partial denervation is more widespread than is suspected clinically in paralytic poliomyelitis. Electrophysiological study.

Clinical evaluation, quantitative analysis of the EMG, and motor unit fiber density were carried out on 34 selected patients that suffered paralytic poliomyelitis. 50% of the subjects developed a late and slowly progressive weakness. Automatic analysis of the electromyogram showed a great increase in mean amplitude in weak muscles but also in hypertrophic ones, and in other muscles that had normal strength. Increase in mean amplitude and in motor unit fiber density was greater in the weaker muscles. The increased amplitude ad motor unit fiber density found in clinically unaffected muscles confirms that neurogenic atrophy is more widespread than is suspected clinically. Thus, the late deterioration of function developed in some of the patients always takes place in muscles which are previously damaged and partially depleted in motor units. Widespread neurogenic involvement of the muscles can play an important role in the late deterioration of these patients.

Adolescent↗
PubMed1980

Ratio between the amplitude of sensory evoked potentials at the wrist in both hands of left-handed subjects.

Maximum sensory conduction velocity, duration and amplitude of the sensory evoked potentials at the wrist on stimulating digits 1, 2, 3 and 5, were determined bilaterally in 21 left-handed subjects with an age range from 6 to 47 years. The amplitude of the sensory evoked potential at the wrist was larger in the right hand. This asymmetry is the reverse of the one previously observed in right-handed infants and adults. It could be physiological and suggests a difference in density of sensory innervation between the two hands. Asymmetry of sensory innervation can be helpful in the study of hand dominance.

Adolescent↗
PubMed1979

Single fibre electromyography in central core disease.

Single fibre electromyography in the extensor digitorum communis muscle was studied in five patients with central core disease. The average number of muscle fibre action potentials belonging to the same motor unit was higher in patients than in healthy subjects of the same age. The increase in motor unit fibre density is consistent with increased terminal innervation ratio described in other papers about central core disease.

Adolescent↗
PubMed1978

Electrophysiological aspects of sensory conduction velocity in healthy adults. 2. Ratio between the amplitude of sensory evoked potentials at the wrist on stimulating different fingers in both hands.

The normal ratio between the amplitude of the sensory evoked potential (SEP) at the wrist on stimulating digits 1, 2, 3, and 5 was determined in 44 healthy adult subjects. The first digit had the larger amplitude, and the fifth digit the smallest SEP. The amplitude expresses the density of sensory innervation in each finger. The ratio between the amplitude of different fingers varied according to the age of the subject. The amplitude of the SEP from a digit innervated by the median nerve decreased in the elderly more than the SEP amplitude of the digit innervated by the ulnar nerve, probably because of a chronic compression in the carpal tunnel. The changes in the normal amplitude ratio can be applied to the topographic diagnosis of radicular and brachial plexus lesions if a fixed segmental sensory innervation of the hand is accepted. In 44 right handed subjects the amplitude of the sensory evoked potentials at the wrist was significantly larger in the left hand. This asymmetry of sensory innervation between hands could be physiological, and suggests a greater density of sensory innervation in the left hand of right handed subjects.

Adult↗
PubMed1975

Peripheral neuropathy detected on electrophysiological study as first manifestation of metachromatic leucodystrophy in infancy.

A case of infantile metachromatic leucodystrophy is described in which symptoms started at 1 year of age with weakness and hypotonus in the lower extremities. The electrophysiological status was typical of a polyneuropathy, showing fibrillation and a reduction of the nerve conduction velocity to 30 percent of the average for normal children of the same age. Clinical signs of a central lesion and mental regression were not evident until a year later. Nerve biopsy showed metachromatic granules in the phagocytes and in the Schwann cells, confirming the diagnosis of metachromatic leucodystrophy. In peripheral neuropathy in infancy without obvious cause, a nerve biopsy is the most appropriate method for diagnosis of the metachromatic leucodystrophy.

Child, Preschool↗