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Biomedical subjects

F Torres

Publications and source records attributed to F Torres.

At least 109 records · Page 6Linked to original sources
PubMed1985

Cerebral dysfunction after chronic hypoxia in children.

Although the long-term effects of acute anoxia have been studied, the effects of chronic hypoxia on the developing human brain have received little attention. We studied children with a cyanotic congenital heart defect to assess the impact of chronic hypoxia by eight measures: neurologic examination, visual evoked response, EEG, behavioral adjustment, cognitive, perceptual-motor, and attentional functioning, and school performance. On outcome evaluation, these children evidenced diverse neurophysiologic dysfunction. Chronic hypoxia was associated with impaired motor function, inability to sustain attention, and low academic achievement.

Brain Diseases↗
PubMed1984

Critical frequency of photic driving in the diagnosis of multiple sclerosis.

Pattern visual evoked response (PVER) and critical frequency of photic driving (CFPD) to repetitive flash stimuli were studied in 68 consecutive patients suspected of multiple sclerosis (MS) and 15 normal controls to assess the diagnostic value of combined PVER-CFPD testing. Clinically, 38 qualified for the diagnosis of MS while 30 did not. The CFPD was found to be unreliable for detecting optic nerve dysfunction (OND) in MS, since well-defined photic driving at all frequencies above 40 flashes per second was not present in 14 patients without MS (47%) and in three normal control subjects (20%). The PVER, on the other hand, was highly sensitive and specific for OND, being abnormal in 12 patients with definite MS (92%) but in none of the normal controls. It is concluded that PVER by itself is a valuable test for the diagnosis of OND in MS and additional CFPD testing is uninformative and may even be misleading.

Adolescent↗
PubMed1984

Photic driving in the early premature infant.

Thirty-two infants born at gestational ages of 27-32 weeks were subjected to isolated flashes and intermittent photic stimulation. Their gestational age (GA) was assessed by maternal dates, physical examination and, when possible, examination of lens vasculature. The babies were selected for being of less than 33 weeks GA and being normal for GA on examination. Responses to isolated flashes were present in 63% and photic driving at 2-10 f/sec was present in 66% of the babies. Apparent discrepancies of these findings with previous reports about photic driving in prematures are discussed.

Electroencephalography↗
PubMed1983

The electroencephalogram of elderly subjects revisited.

The EEGs of 98 elderly volunteers were compared with those of 84 patients with a recent cerebral infarction who had achieved a stable clinical course. All subjects were uniformly evaluated according to a special protocol. The elderly volunteers were accepted for the study if they had no history, signs or symptoms of central nervous system disease. The EEGs were found to be significantly different between the two groups of subjects in several aspects. These included not only possible abnormalities, focal or diffuse, but also some normal features, such as alpha frequency and responses to photic stimulation and to hyperventilation. Groups of these differentiating features were analyzed. Using the single variable of ER (evoked response), discrimination of 80% was achieved. The variables that distinguish the volunteers from the patients may be used in the future to determine whether they are helpful in differentiating normals from patients with conditions other than stroke.

Aged↗
PubMed1983

Later competence and adaptation in infants who survive severe heart defects.

A model of risk potential for developmental outcome was created based on cardiac, medical, surgical, and family-stress factors in 31 children with transposition of the great arteries who had undergone reparative open heart surgery utilizing cardiopulmonary bypass during infancy. Impact of these potential risk factors was assessed by 4 current neurologic measures (neurologic anatomic abnormalities, functional impairment, electroencephalograph [EEG], and Pattern Visual Evoked Potential [PVEP]) and 4 psychologic measures (IQ, achievement, perceptual-motor function, and behavior). Results indicated that adverse developmental outcome was significantly associated with the following medical risk variables: failure of palliative surgery to alleviate hypoxia, prolonged hypoxia, growth failure, congestive heart failure, absence of ameliorating shunting heart defects, stroke, and CNS infection; and two psychosocial moderator variables: socioeconomic status and current life stress. Analysis of a "cumulative risk score" indicated significantly higher risk scores in children with abnormal EEGs, PVEPs, and neurologic examinations. The cumulative risk score highly correlated with composite neurologic outcome (r = .62), IQ (r = -.66), achievement (r = -.60), and perceptual-motor function (r = -.48). While overall outcome was favorable for children with TGA who experienced a single risk event, outcome was compromised if multiple risk factors occurred.

Achievement↗
PubMed1982

Hemiplegic migraine in childhood: diagnostic and therapeutic aspects.

Focal neurologic deficits, particularly hemiplegia, are occasionally observed in the pediatric migrainous population during the headache attack and are often mistaken for other neurologic or neurosurgical conditions. Clues to the correct diagnosis, illustrated by three patients in this report are: (1) rapid spontaneous recovery from the acute neurologic deficit, (2) striking electroencephalographic abnormalities, frequently consisting of focal slow waves during the acute stage, with rapid resolution, (3) significant past history of recurrent episodes, and (4) positive family history of migraine. Review of previously reported cases indicates that cerebral arteriography in the acute stage should be avoided if the clinical syndrome is typical. Preliminary results of prophylactic treatment with propranolol are encouraging; smaller dosage than those previously recommended sometimes can be effective.

Adolescent↗
PubMed1981

A test to determine parameters of aerobic function during exercise.

A short-duration cycle ergometer exercise test has been developed that allows four parameters of aerobic function to be discerned. These are the maximum O2 uptake, anaerobic threshold, work efficiency, and the time constant for O2 uptake kinetics. The test form is a ramp of 4-8 min duration to the limit of tolerance. The parameters determined from the ramp faithfully reproduced those obtained from several standard procedures. We conclude that a profile of aerobic function in man can be obtained from a single short-duration ramp test.

Adult↗
PubMed1979

Frequency-amplitude gradient: a new parameter for interpreting pediatric sleep EEGs.

We describe an EEG pattern in pediatric sleep records, called the frequency-amplitude gradient (FAG). This pattern is a progressive decrement in voltage from occipital to frontal areas, with an accompanying decrease in slow frequencies in the same posterior-anterior direction. We report the results of examining 100 sleep records of children between birth and 10 years of age, with a review of the clinical diagnoses. There is a positive correlation between the severity of illness and the presence or absence of FAG. Furthermore, acute illnesses appear to be associated with the transient loss of the FAG, and with its return to normal with clinical recovery. The presence or absence of a FAG should be incorporated into the criteria for determining the normality of pediatric sleep EEGs.

Brain↗
PubMed1979

Hypercapnic alteration of visual evoked responses in acute cerebral infarction.

To determine the effect of inhaled carbon dioxide on acute ischemic cerebral injury, we have compared occipital visual evoked responses (VER) at baseline and during hypercapnia in 20 patients with acute unilateral cerebral infarction (ten with and ten without homonymous hemianopsia) and in ten normal controls. Visual evoked responses were judged on the basis of interhemispheral symmetry. In eight of ten controls and six of 20 patients, baseline VERs were symmetrical and remained unchanged during hypercapnia. In 14 patients with asymmetrical baseline VERs, hypercapnia caused improvement of symmetry in five, worsening in three, and no change in six. Hypercapnic vasodilation may be either beneficial or deleterious to cerebral function in patients with acute cerebral infarction.

Acute Disease↗
PubMed1979

Visual evoked potentials in the evaluation of "cortical blindness" in children.

Visual evoked responses (VERs) to brief light flashes were recorded from occipital regions in a group of 30 "cortically blind" children aged 4 months to 15 years and were compared with those of 31 children of similar age range who had the same type of central nervous system diseases but without signs or symptoms of blindness. The VERs were analyzed for amplitude, number of peaks, and morphology, following a method used previously by other authors. All the responses had some degree of abnormality, but there were no significant differences between the two groups. The findings suggest that recording of VERs is not always an accurate method for diagnosis of cortical blindness in children since the presence of abnormal responses is not incompatible with normal vision. Only 1 patient with coritcal blindness showed no response.

Adolescent↗
PubMed1977

Radionuclide bolus angiography: a technique for verification of brain death in infants and children.

Fifteen infants and children, 11 of whom had clinical brain death and four of whom were comatose, were evaluated with the radionuclide bolus study and electroencephalography. Clinical criteria for brain death included: (1) absence of spontaneous respirations, (2) absence of cephalic reflexes, and (3) unresponsiveness. Results demonstrated complete correlation among clinical examination, EEG, and radionuclide study in 79% of cases. An approach to the evaluation of the infant or child with possible brain death is outlined utilizing serial examinations, radionuclide bolus study, and electroencephalography. The radionuclide bolus study appears to be a safe, rapid, portable technique which can be used for this purpose in infants and children.

Angiography↗
PubMed1977

Paths and ways of epilepsy.

The importance assigned to different brain sites for the initiation and conduction of epileptic activity has changed with times, the significant zones being somehow alternatively the cerebral cortex and various centrencephalic structures. Rather than renew this controversy, the available experimental evidence indicating that for the production of epilepsy, the entire brain, or at least several structures and not only discrete cortical or subcortical focal areas must participate, is critically reviewed.

Cerebellum↗
PubMed1975

A method for prediciting localised areas of cerebral ischemia from visual evoked responses.

Responses to light flashes recorded from several scalp electrodes of a normal subject at rest and during alternate compression of the carotid arteries in the neck are analysed. The diffences found in response characteristics between the subject at rest and during carotid compression may serve as indicators of localised areas of cerebral ischemia. The results indicate a strong evidence that information about localised areas of cerebral ischemia is contained in the cepstra of the averaged visual evoked responses. The probability with which such areas can be localised using cepstral values as samples and linear multiple regression techniques for classification purposes has been estimated for our procedure and our sample size as being: Pa equals 79 plus or minus 17 per cent for left-right localisation, and Pb equals 61 plus or minus 16 per cent for left-none-right localisation.

Adult↗