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Biomedical subjects

P Fedio

Publications and source records attributed to P Fedio.

At least 55 records · Page 3Linked to original sources
PubMed1984

Cortical abnormalities in Alzheimer's disease.

Regional cerebral glucose metabolism, an index of neuronal activity, was compared in 20 patients with Alzheimer's disease and 8 age-matched normal volunteers by positron emission tomography following [18F]2-fluoro-2-deoxy-D-glucose administration. Overall cortical glucose utilization in the Alzheimer's group was 10 to 49% below that of control individuals. The posterior parietal cortex and contiguous portions of posterior temporal and anterior occipital lobes were most severely affected; frontal cortex was relatively spared. This pattern of cortical involvement is consistent with the major clinical features of Alzheimer's disease. Comparison of patients with early and more advanced dementia suggested that a substantial decline in glucose metabolism occurs before cognitive impairment becomes evident; once the patient is symptomatic, however, small additional metabolic decrements are associated with a marked deterioration in intellectual function.

Aged↗
PubMed1984

Attentional deficits in long-term survivors of childhood acute lymphoblastic leukemia (ALL).

Simple alerted auditory reaction time (SRT) behavior with various foreperiods was investigated in a group of long-term survivors of childhood ALL who were in continuous first remission. As part of therapy, the patients had received cranial irradiation and intrathecal chemotherapy to prevent the development of central nervous system leukemia. The patients were divided into three groups on the basis of CT brain scan findings: (1) those with normal CT scans (n = 10); (2) those with evidence of cortical atrophy (n = 8), and (3) those with intracerebral calcifications (n = 5). The SRT results indicated significant differences between patients with normal and abnormal CT scans. Specifically, patients with abnormal scans reacted slower, and this latency was exaggerated by increasing the length of the warning interval. Furthermore, they reacted with larger variability which increased with the prolongation of testing. Moreover, the severity of impairment was related to the type of CT-scan abnormality: patients with calcifications performed more poorly than patients with evidence of atrophy. The present results revealed a strong correlation between the presence and type of CT-scan abnormalities and attentional performance in long-term survivors of childhood ALL.

Adolescent↗
PubMed1984

Computerized tomography and neuropsychological test measures in adolescents with obsessive-compulsive disorder.

The authors administered CAT scans and neuropsychological tests to 16 adolescents with obsessive-compulsive disorder (mean age +/- SD = 13.7 +/- 1.6 years) and 16 matched controls. The patients had a mean ventricular-brain ratio (VBR) significantly higher than the controls' and showed spatial-perceptual deficits similar to those found in patients with frontal lobe lesions. Memory, reaction time, and decision time did not differ significantly from controls'. Neurodevelopmental examination of seven patients yielded a high frequency of age-inappropriate synkinesias and left hemibody signs. These results suggest CNS dysfunctioning in children with obsessive-compulsive disorder, with possible right cerebral involvement. However, the patients' neuropsychological test deficits and VBRs were not correlated.

Adolescent↗
PubMed1983

Word production and comprehension in Alzheimer's disease: the breakdown of semantic knowledge.

Relatively mildly impaired patients with suspected Alzheimer's disease (N = 14; Verbal IQ = 96) and normal controls of similar age and education (N = 11) were administered tests requiring production (naming and fluency) and comprehension of single words. Word comprehension was assessed on a superordinate level (rating words for degree of "pleasantness") and on a more specific level (matching abstract pictorial representations with printed words denoting objects, action, emotions, and modifiers). Performance on standardized measures of semantic knowledge (Vocabulary and Similarities subtests of the WAIS) was also evaluated. The naming and fluency abilities of the Alzheimer's patients were found to be highly correlated (r = .80) and impaired. Naming errors often consisted of semantic field errors which were either hierarchically or linearly related to the target name. In comparison with normals, verbal fluency was characterized by a tendency to generate proportionally more category names concurrent with reduced production of items within a category. Single-word comprehension was also impaired, except when judgments of affective meaning were required. It was argued that these results suggest that Alzheimer's disease may lead to a specific disruption in semantic knowledge characterized by a difficulty in differentiating between items within the same semantic category concurrent with the relative preservation of broader categorical information.

Aged↗
PubMed1983

Alzheimer's disease: focal cortical changes shown by positron emission tomography.

Local rates of cortical glucose metabolism were estimated by positron emission tomography in 13 right-handed patients with Alzheimer's disease. Individuals with disproportionate failure of language function had markedly diminished metabolism in the left frontal, temporal, and parietal regions. Patients with predominant visuo-constructive dysfunction evidenced a hypometabolic focus in the right parietal cortex. Patients with memory failure as the most apparent feature had no significant metabolic asymmetry in cortical regions. In all subjects, verbal competency generally correlated with metabolic activity in the left frontal and temporal areas, while visuo-constructive test performance was linked to glucose utilization in the right parietal lobe.

Aged↗
PubMed1983

Neuropsychological characteristics of college males who show attention dysfunction.

400 male college students were screened on a measure of vigilance, the Continuous Performance Test. A Good Attention Group (upper 5% of the CPT score distribution) and a Poor Attention Group (lower 5%) were selected and compared on a series of perceptual and motor tests. The Good Attention Group was superior to the Poor Attention Group on most of the measures. The largest differences were found on tests assessing perceptual-motor organization. Attention dysfunction in this non-patient sample seems to be associated with performance deficits. Over-all, the pattern of neuropsychological results seen in the Poor Attention Group is not similar to the pattern seen in patients with lateralized brain damage but appears more similar to that seen in those with bilateral and diffuse cortical damage.

Adult↗
PubMed1982

Lysine vasopressin in Alzheimer disease.

The effects of lysine vasopressin on memory and cognitive deficits in Alzheimer disease was investigated. In a double-blind study, seven patients were given 16 units of lysine vasopressin per day for 10 days and were compared with seven different patients receiving placebo. No significant difference in performance between the vasopressin and placebo-treated groups was found in tests designed to evaluate learning, memory, and perception. However, significantly greater improvement in reaction time was seen in the vasopressin-treated group, although this effect was delayed and may have been contributed to by factors other than drug activity.

Alzheimer Disease↗
PubMed1980

Deficits in short-term auditory memory for verbal material following right temporal removals in humans.

Right, as well as left, temporal patients were significantly impaired on shot-sterm auditory memory for consonant trigrams. The severity of the deficit shown by both groups was not related to the association value (low, medium, high) of the trigrams or the duration of the intertrial intervals (from 6 sec to 1 min) used in this study. Right temporal patients were also deficient on tests of tonal memory and delayed facial recognition. The results are discussed in terms of a sequential model of information processing involving modality-specific short-term memory and material-specific long-term retention.

Adult↗
PubMed1977

Quantitative analysis of interictal behavior in temporal lobe epilepsy.

Patients with unilateral temporal epileptic foci were contrasted with normal subjects and patients with neuromuscular disorders in the evaluation of specific psychosocial aspects of behavior. Eighteen traits were assessed in equivalent questionnaires completed by both subjects and observers. The epileptic patients self-reported a distinctive profile of humorless sobriety, dependence, and obsessionalism; raters discriminated temporal lobe epileptics on the basis of circumstantiality, philosophical interests, and anger. The right temporal epileptic displayed emotional tendencies in contrast to ideational traits of left temporal epileptic. Right temporal epileptics exhibited "denial," while left temporal epileptics demonstrated a "catastrophic" overemphasis of dissocial behavior. The results support the hypotheses that sensory-affective associations are established within the temporal lobes, and that, in man, there exists a hemispheric asymmetry in the expression of affect.

Adolescent↗
PubMed1976

Functional representation on the medial aspect of the frontal lobes in man.

Sensorimotor responses to stimulation of the medical frontal and cingulate area were studied in seven unrestrained, unsedated patients who suffered from intractable seizures. Complex postural synergies involving the trunk and proximal extremities appeared contralaterally or occasionally bilaterally. Contraversive turning of head and eyes was not observed. Sensory responses from the supplementary motor area were referred contralaterally and focally; those from the cingulate gyrus were widely referred. Speech impairment from stimulation of the supplementary motor area showed striking similarities with that obtained from stimulation in the frontostriatal region or lateral aspect of the frontal lobe. The observations support the hypothesis that interference with striatal function may be the basis of speech inhibition produced by stimulation of the frontal lobe.

Brain Mapping↗
PubMed1975

Recognition thresholds in the central and lateral visual fields following temporal lobectomy.

This study examined recognition thresholds for patients wtih unilateral left or right temporal lobectomy and for normal subjects. Material was projected tachistoscopically and successively to the center, left, and right visual fields. Stimuli were random designs and three-letter words oriented vertically. The recognition thresholds of the left temporal and normal groups were comparable, for both sets of stimuli. In contrast, the right temoral group was impaired in the recognition of words and random designs in the central and lateral fields. Results were seen to reflect the processing of units of visual information, whether in the form of letters or random designs, which at this elementary level relates to the right temporal lobe functioning.

Adolescent↗