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Biomedical subjects

S Corkin

Publications and source records attributed to S Corkin.

At least 73 records · Page 4Linked to original sources
PubMed1987

Abstract reasoning in age-related neurological disease.

Subjects with a variety of neurological disorders including Alzheimer's disease (AD) were tested for abstract reasoning ability with two new tests that do not involve high-order language, memory, or visuospatial skills. All groups performed at the normal level except the patients with AD, who performed poorly on the test of logical reasoning ability, but relatively well on the test of the ability to recognize relationships between common objects. The results suggest that in AD, relational abilities may remain intact well into the disease, whereas generational abilities may be among the cognitive skills that are impaired early in the course of the disease.

Alzheimer Disease↗
PubMed1986

Cholinesterases in cerebrospinal fluid. Correlations with clinical measures in Alzheimer's disease.

Acetylcholinesterase and butyrylcholinesterase activities in cerebrospinal fluid were measured in 17 patients with Alzheimer's disease and 6 control patients, as potential clinical measures of impaired cholinergic neurotransmission in Alzheimer's disease. The activity of butyrylcholinesterase was decreased in patients with Alzheimer's disease compared to that observed in control patients, but there was overlap between values in the 2 groups. Low butyrylcholinesterase activity was correlated with severity of dementia, memory impairment, and language disorder. Acetylcholinesterase activity was significantly correlated with visual contrast sensitivity, but not with dementia severity, and did not differentiate patients with Alzheimer's disease from control cases. These results suggest that cholinesterases in cerebrospinal fluid are related to brain cholinesterases, and indicate that the activities of acetylcholinesterase and butyrylcholinesterase should be distinguished in studies of cerebrospinal fluid.

Acetylcholinesterase↗
PubMed1986

Semantic impairment and anomia in Alzheimer's disease.

Impairment in naming visually presented objects was investigated in patients with a clinical diagnosis of Alzheimer's disease. Impaired object naming correlated with difficulty listing the names of objects from a specified semantic category and with erroneous selection of words semantically related to the correct names for objects in a name recognition test. These results suggest that patients with Alzheimer's disease have a semantic impairment characterized by inability to distinguish among objects that are members of the same semantic category, and that this impairment is associated with difficulty producing the names for objects. Semantic impairment was present in patients with normal ability to discriminate visually presented shapes, indicating that the semantic deficit in Alzheimer's disease occurs independently of abnormalities of visuospatial function. Patients tended to make errors on the same items in both confrontation naming and name recognition tests, suggesting that the semantic impairment in Alzheimer's disease involves loss of information about specific objects and their names.

Aged↗
PubMed1986

Equivalent forms of the Boston Naming Test.

In order to develop a test of naming ability that is sensitive to changes in performance on repeated testing, but is unbiased by practice effects, the 85 items of the Boston Naming Test (BNT) were divided into two 42-item forms. Both forms were given to 15 healthy adult subjects, 24 patients with a clinical diagnosis of Alzheimer's disease, and 17 patients with other brain lesions. The reliability of the BNT was high as measured by coefficient alpha and interitem correlations. Performance on the two forms of the test was similar as indicated by mean scores and by correlations between scores. The BNT score includes uncued (spontaneous) and cued responses. When uncued responses were analyzed separately, the reliability and equivalence of the forms remained strong. Using uncued scores therefore does not alter the psychometric properties of the test, and considerably reduces administration time. The modification of the BNT described here should be useful in studies in which repeated measurements are obtained for the purpose of detecting changes in naming ability.

Alzheimer Disease↗
PubMed1985

Spatial vision in Alzheimer's disease. General findings and a case report.

Visual contrast sensitivity to sinusoidal gratings of five spatial frequencies was measured in 15 patients with Alzheimer's disease and in eight control subjects. Contrast sensitivity thresholds were elevated at all frequencies in 14 patients compared with control subjects. The 15th patient was unique: she had an impairment in object and face recognition so severe that she could not recognize her husband visually. Her sensitivity to low and intermediate frequencies was markedly reduced in relation to that of other patients, whereas her sensitivity to the highest frequency tested equaled theirs. These observations emphasize the importance of low spatial frequency information for visual object and face recognition.

Blood Physiological Phenomena↗
PubMed1985

Diminished ability to interpret and report internal states after bilateral medial temporal resection: case H.M.

These experiments centered around H.M., a 54-year-old man who became amnesic 27 years ago after a bilateral resection in the medial temporal lobe region for epilepsy. In order to document the clinical reports that he rarely comments on such internal states as pain, hunger, and thirst, his thermal pain perception was examined in relation to his other somatosensory capacities, and his reports of hunger and thirst were assessed before and after meals. In order to investigate the effect of limited memory ability on the reporting of internal states, H.M.'s performance was compared with that of 5 other subjects with global amnesia. The results provided evidence that H.M.'s information about internal states is less available or less accessible than normal and that his impairment is not attributable to his well-documented memory deficit. Instead, it is believed that the bilateral resection of the amygdala accounts for H.M.'s poor appreciation of his internal states.

Adult↗
PubMed1985

The effects of dietary neurotransmitter precursors on human behavior.

The neurotransmitter precursors tryptophan and tyrosine are present in a variety of foods. In order to document possible effects of tryptophan and tyrosine on human behavior, single oral doses of these substances and matched placebos were administered to 20 men in a double-blind, crossover study. Various tests of mood state and performance were then administered. Tryptophan increased subjective fatigue and decreased self-ratings of vigor and alertness, but did not impair performance on any of the tests. Tyrosine produced no effects in our young population compared with placebo, but did decrease reaction time relative to tryptophan. It may be concluded that tryptophan has significant sedative-like properties, but unlike other sedatives may not impair performance.

Adult↗
PubMed1985

Effectiveness of attentional cueing in older and younger adults.

It has been proposed that aging selectively affects cognitive processes that are effortful rather than automatic and that active, memory-driven attentional selectivity is impaired in old adults. The present study evaluated attentional selectivity in two groups of healthy adults: a younger group with mean age 19.4 years and an older group with mean age 63.6 years. A visual simple reaction time task was used in which a warning cue appearing at the beginning of each trial indicated the probable location of the target signal. Response times of both groups were shortest when the stimulus appeared at the expected location and longest when it appeared at the unexpected location; responses of both groups were also faster on trials with a 3-s warning interval compared with a 2-s warning interval. These effects of spatial and temporal expectancy were as substantial in older adults as in younger adults. Reasons for the difference between these findings and earlier results are discussed.

Adolescent↗
PubMed1984

Prognostic factors for life expectancy after penetrating head injury.

Survival curves were made for 190 World War II veterans with penetrating head injuries, and for 106 WW II veterans with peripheral nerve injuries who matched the subjects with head injuries with respect to age at injury, years of formal education, and preinjury intelligence-test score. The results indicated that penetrating head injury coupled with posttraumatic epilepsy shortened life expectancy in subjects who survived the early postinjury period, but that head injury alone did not. Educational level was also a significant variable independent of seizures: subjects with more education survived longer than those with less education. Age at injury and the difference between preinjury and postinjury intelligence-test scores did not predict survival status.

Adolescent↗
PubMed1984

Recent advances in the neuropsychology of Alzheimer's disease.

Memory, language, and visuospatial impairments are prominent neuropsychological deficits in Alzheimer's disease. The neuropsychological characteristics of Alzheimer's disease are unique, and contrast with those of other brain diseases. Neuropsychological study of patients with Alzheimer's disease may be useful in discovering the neuronal basis of cognitive processes, in differential diagnosis of dementia, and in evaluating treatment.

Alzheimer Disease↗
PubMed1984

Selective subject attrition in a longitudinal study of head-injured veterans.

Recent longitudinal studies of aging have suggested that intellectually inferior subjects selectively drop out during the course of the investigation. This issue of subject attrition was addressed in a neuropsychological study of 314 veterans who had sustained head or peripheral nerve injuries in World War II. These men were examined originally by Teuber and his colleagues at New York University in the 1940s and 1950s, and the veterans' participation was sought for a 40-year follow-up study at the Massachusetts Institute of Technology. In the current follow-up study, the veterans were subdivided according to their response to recent recruitment letters: those who agreed to be retested, those with whom recent contact was established but who declined to participate, those who did not reply to our correspondence, and those who were deceased. Those who agreed to be retested in the 1980s had significantly more education and achieved significantly higher Army General Classification Test scores both before and after injury than did the untested cohort. Even with the selective subject attrition, however, the remaining sample represented a broad range of intellectual competence.

Craniocerebral Trauma↗