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Biomedical subjects

G A Chase

Publications and source records attributed to G A Chase.

At least 19 recordsLinked to original sources
PubMed1992

Quantitative changes in mesial temporal volume, regional cerebral blood flow, and cognition in Alzheimer's disease.

Twenty-six patients with moderately severe Alzheimer's disease (AD) and 16 normal control subjects were studied using either quantitative magnetic resonance imaging (MRI) measures of mesial temporal atrophy (15 patients with AD and 16 normal control subjects) and/or quantitative radioactive iodine 123-N-isopropyl-iodoamphetamine single-photon emission computed tomography (SPECT) assessment of regional cerebral blood flow (20 patients with AD and eight normal control subjects). Nine individuals with AD and eight normal control subjects underwent both structural and functional imaging. On MRI, patients and controls were best discriminated using left amygdala and entorhinal cortex volumes, and on SPECT they were best discriminated by relative left temporoparietal cortex blood flow. Combining these MRI and SPECT measures yielded 100% discrimination. Relative left temporoparietal SPECT regional cerebral blood flow and left superior temporal gyral MRI volume correlated best with severity of cognitive deficit in patients with AD. Mesial temporal MRI atrophy exceeded generalized cerebral shrinkage. Both SPECT and MRI regional changes accorded with areas known to be affected by AD neuropathology.

Aged↗
PubMed1992

Putamen volume reduction on magnetic resonance imaging exceeds caudate changes in mild Huntington's disease.

The characteristic pathological features of Huntington's disease (HD) are neostriatal atrophy and neuronal loss. Although neuroradiological studies often show caudate atrophy in patients with moderate HD, frequently no caudate atrophy is found early in the illness. There have been no quantitative reports to date on in vivo putamen volume measures in mild HD, although the structure is known to be neuropathologically involved in the illness. We measured volumes of caudate nucleus and putamen and bicaudate ratios (BCR) from magnetic resonance images, blind to diagnosis, in 15 patients with mild HD and 19 age- and sex-matched control subjects using a computerized image analysis system. The region showing greatest atrophy was the putamen, which was reduced 50.1% in mean volume in HD patients compared with control subjects (p less than 0.000001). In contrast, caudate volume was reduced 27.7% (p = 0.004). BCR was increased 28.5% in HD patients (p = 0.0002). Discriminant function analysis was 94% effective in identifying the diagnostic group based on putamen volume alone, whereas caudate measures had considerable overlap. Correction of putamen volume for head size led to 100% separation by group. Putamen measures and BCR correlated with neurological examination scores but caudate volume did not. Volumetric measurement of putamen is a more sensitive indicator of brain abnormalities in mild HD than measures of caudate atrophy.

Adult↗
PubMed1992

Social language use in parents of autistic individuals.

Social language use (pragmatics) in parents of autistic individuals and controls was compared. Autism parents displayed atypical pragmatic behaviours more often than controls. Preliminary factor analysis suggested three parsimonious groupings of pragmatic abnormalities: Disinhibited Social Communication, Awkward/Inadequate Expression, and Odd Verbal Interaction. The pragmatic features observed in some autism parents are milder but conceptually similar to the social language deficits of autism. Possible reasons for familial aggregation of pragmatic language deficits are discussed.

Autistic Disorder↗
PubMed1992

Discriminant validity of a reduced set of Mini-Mental State Examination items for dementia and Alzheimer's disease.

Linear discriminant analysis was used to construct a series of discriminant functions including subsets of demographic variables and Mini-Mental State Examination item responses for a case series and a population sample. A 9-item discriminant function including the variables for time orientation, recall, calculation, copying a figure, age, writing, 3-step command, naming, and race distinguished demented subjects from community controls with 91% sensitivity and 88% specificity. The same discriminant function classified Alzheimer's disease patients and controls with 96% sensitivity and 98% specificity. This discriminant function has been cross-validated as a potential screening instrument for Alzheimer's disease in a community-based sample.

Aged↗
PubMed1992

Visual hallucinations in patients with macular degeneration.

OBJECTIVE: This study was undertaken to determine the prevalence of visual hallucinations in patients with macular degeneration, describe such hallucinations phenomenologically, and possibly determine factors predisposing to their development. METHOD: Using a case-control design, the authors screened 100 consecutive patients with age-related macular degeneration for visual hallucinations. Each patient with visual hallucinations was matched to the next three patients without hallucinations. The patients and comparison subjects were compared in terms of scores on the Beck Depression Inventory, Eysenck Personality Questionnaire, Telephone Interview for Cognitive Status, and a structured questionnaire including demographic characteristics, family history, and medical and psychiatric history. Ophthalmologic data were obtained by chart review. RESULTS: Of the 100 patients, 13 experienced visual hallucinations. Four variables were significantly associated with having hallucinations: living alone, lower cognition score, history of stroke, and bilaterally worse visual acuity. Hallucinations were not associated with family or personal history of psychiatric disorder or with personality traits. In 11 (84.6%) of the 13 patients, the hallucinations had begun in association with an acute change in vision. CONCLUSION: These results indicate that visual hallucinations are prevalent among patients with macular degeneration. They appear unrelated to primary psychiatric disorder. The predisposing factors of bilaterally worse vision and living alone support an association with sensory deprivation, while history of stroke and worse cognition support a decreased cortical inhibition theory.

Aged↗
PubMed1991

Platelet serotonin, a possible marker for familial autism.

Serotonin (5HT) levels in platelet-rich plasma were measured in 5 autistic subjects who had siblings with either autism or pervasive developmental disorder (PDD), 23 autistic subjects without affected siblings, and 10 normal controls. The 5HT levels of autistic subjects with affected siblings were significantly higher than probands without affected siblings, and autistic subjects without affected siblings had 5HT levels significantly higher than controls. Differences in 5HT levels remained significant after adjustment for sex, age, and IQ. These results suggest that 5HT level in autistic subjects may be associated with genetic liability to autism.

Adolescent↗
PubMed1991

Psychiatric disorders in the parents of autistic individuals.

Eighty-one parents of 42 autistic probands and 34 parents of 18 Down syndrome probands were examined using a semistructured, investigator-based version of the Schedule for Affective Disorders and Schizophrenia Lifetime Version to estimate the lifetime risk of psychiatric disorder. The lifetime prevalence rate of anxiety disorder was significantly greater in parents of autistic probands than in parents of Down syndrome probands. The lifetime prevalence rate of major depressive disorder, while not significantly different in cases and controls, may be high in the parents of autistic probands (27%) in comparison with populations rates.

Anxiety Disorders↗
PubMed1991

Physician practices in the diagnosis of dementing disorders.

Because there are both treatable and untreatable causes of dementia, the physician's ability to conduct (or refer a patient for) a differential diagnosis could have a profound effect on health outcomes for patients and on health care costs. This study was undertaken to assess physician practices with regard to the diagnosis of dementing disorders. Data from 53 physicians (a response rate of 48%) in several specialties were obtained from a self-administered mail questionnaire. Results indicate that the majority of physicians provided history taking, physical examination, and neurological examination. Physicians were more likely to refer patients for psychiatric and neuropsychological examinations than to provide these services themselves. The results also point to deficiencies in two key areas: the use of formal, published diagnostic criteria, and the use of mental status and cognitive function tests. Over 75% of physicians surveyed did not use either DSM-III or NINCDS-ADRDA diagnostic criteria, and 42% of physicians did not provide any mental status tests themselves. The need for continuing education to close knowledge gaps is emphasized.

Aged↗
PubMed1991

Adolescent women's contraceptive decision making.

A modified rational decision model incorporating salient events and social influences (particularly from sexual partners) is used to analyze adolescent women's consistent use of oral contraceptives (OCs) over a six-month period. Data are taken from a panel study of 308 clients of an inner-city family planning clinic. Expected OC use was computed for each subject on the basis of subjective expected utility (SEU) theory, and is found in multivariate analyses to be a significant predictor of actual OC use. In addition, variables representing baseline and follow-up partner influences, the salience of pregnancy for the subject, and positive side effects of OCs during the first months of use are found to predict OC use. Partner's support of OC use during follow-up and positive side effects of OCs are found to predict OC use among subjects for whom OC use was not the expected decision according to baseline SEU. Implications of the findings for models of adolescents' contraceptive behavior and for clinicians are discussed.

Adolescent↗
PubMed1990

A family history study of neuropsychiatric disorders in the adult siblings of autistic individuals.

The family history method was used to obtain developmental, social, and psychiatric histories on the 67 adult siblings of 37 autistic probands. Two of 67 siblings (3.0%) were autistic, three siblings (4.4%) had severe social dysfunction and isolation, 10 (15%) had cognitive disorders, and 10 (15%) had received treatment for affective disorder. This study is the first to investigate the frequency of disorders in the adult siblings of autistic probands. These results suggest aggregation of a variety of neuropsychiatric disorders in the siblings of autistic individuals.

Adolescent↗
PubMed1990

Association between family history of affective disorder and the depressive syndrome of Alzheimer's disease.

For each of 41 index patients with probable Alzheimer's disease and a first episode of major depression and 71 nondepressed Alzheimer's disease patients, two first-degree relatives were interviewed by a rater blind to presence or absence of depression in the proband. The depressed patients had significantly more first- and second-degree relatives with depression than did control subjects. The lifetime risk for major depression, adjusted for differences in age distribution, was significantly greater in first-degree relatives of index patients, suggesting that depression in Alzheimer's disease is genetically related to primary affective disorder. Alzheimer's disease may be useful for studying aspects of depressive pathophysiology.

Age Factors↗
PubMed1990

Psychiatric symptoms and nursing home placement of patients with Alzheimer's disease.

Two hundred ten community-dwelling patients with Alzheimer's disease were examined prospectively by psychiatrists as part of a longitudinal study. Twenty-five of these patients who were institutionalized during the next 3 years were then matched to 25 patients who were not institutionalized, and the groups were compared. The patients who had been institutionalized had higher scores on standardized psychiatric rating scales but not on formal neuropsychological tests of cognition. These results suggest that potentially treatable (noncognitive) behavioral and psychiatric symptoms are risk factors for institutionalization, and that treating these symptoms might delay or prevent institutionalization of some patients.

Aged↗
PubMed1989

Ventricle-brain ratio, computed tomographic density, and brain area in 50 schizophrenics.

A sample of 50 DSM-III-diagnosed schizophrenics (mean age, 34 years) intentionally biased to contain a relatively high proportion of persistently unemployed persons was compared with a sample of 87 normal volunteers on three computed tomographic measures. These were lateral ventricle-brain ratio, regional brain computed tomographic density values, and brain slice area. Images were made with the same computed tomographic scanner and identical scan parameters. Computed tomographic data were assessed blindly using a computer-linked image array processor and electronic planimeter. Ventricle-brain ratios were significantly higher in schizophrenics, with 28% of the patient sample exceeding 2 SDs of the control mean. Brain area measures were not associated with an enlarged ventricle-brain ratio. Contrary to our prediction, ventricular enlargement was unassociated with most negative symptom ratings, but was correlated with the absence of positive symptoms. A history of abnormal delivery and the presence of left-handedness were significant predictors of an enlarged ventricle-brain ratio on multiple regression analysis. Schizophrenics had a significantly smaller brain slice area compared with normal controls, a finding not attributable to height differences between groups. Brain slice area was inversely correlated with computed tomographic brain density across all subjects. After correction of computed tomographic density values for area using a linear regression model, no significant regional density differences were detectable between normal controls and schizophrenics. Within normal controls there was a significant relationship between social class and brain slice area, but not ventricle-brain ratio.

Adult↗
PubMed1989

Simulation of Huntington's disease onset.

Previous investigators have noted that the type of sampling scheme used to study the natural history of Huntington's disease can affect the observed age of onset distribution. Simulated data are presented to demonstrate that bias is introduced when onset characteristics derived from prevalence samples (i.e., samples of affected individuals alive in the population) are used to evaluate cofactors of disease onset and to compute genetic risk estimates for persons "at risk" of developing the disease. This study demonstrates that prevalence sampling underestimates the proportion of Huntington's disease cases in the population with later onset ages. Using plausible values for onset time, duration, and life expectancy, simulation results suggest that the paternal transmission effect on Huntington's disease onset is overestimated when based on prevalence data.

Adolescent↗
PubMed1989

A chart review study of late-onset and early-onset schizophrenia.

This chart review study compared 54 schizophrenic patients with onset of illness after age 45 years to 54 young and 22 elderly patients with early-onset schizophrenia (before age 45). The index group was more likely to have visual, tactile, and olfactory hallucinations; a greater number of different types of hallucinations; persecutory delusions; and premorbid schizoid personality traits, and was less likely to have thought disorder and affective flattening, than was either comparison group. Among the two elderly groups, index patients had more auditory and visual sensory impairment. Nearly half (48.1%) of the index patients responded to neuroleptic treatment with complete remission.

Adolescent↗
PubMed1988

Linkage studies of Best's macular dystrophy.

Genetic linkage studies are presented for nine kindreds with Best's vitelliform macular dystrophy (BVMD). This condition is an autosomal dominant macular dystrophy with reduced penetrance and highly variable expressivity. Asymptomatic carriers were identified with electro-oculography, fundus photographs and fluorescein angiography. Blood and saliva specimens were obtained from informative family members and genotyped for 26 polymorphic genetic traits. No firm evidence was found for linkage between BVMD and 18 informative markers; the highest positive lod score was z = 0.57 for GPT1 at a recombination fraction of theta = 0.30. An atypical form of vitelliform macular dystrophy (VMD-1) is linked to GPT1 (theta less than 0.05) and is provisionally assigned to chromosome 16pter-p11. Our data are not sufficient to rule out loose linkage for GPT1 and BVMD. Thus we were not able to determine whether BVMD and VMD-1 are allelic mutations or separate genetic disorders. Additional linkage and gene mapping studies of these loci and BVMD (as well as other atypical forms of macular dystrophy) would be useful to further delineate these disorders.

Gene Expression Regulation↗