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Biomedical subjects

J M Swearer

Publications and source records attributed to J M Swearer.

At least 19 recordsLinked to original sources
PubMed2005

Familial Alzheimer disease: decreases in CSF Abeta42 levels precede cognitive decline.

CSF amyloid beta-peptide 42 (Abeta42) levels in presymptomatic subjects with pathogenic mutations in the PS1 gene are significantly lower than in an age-matched control group. Consequently, in these subjects, there is a window of opportunity estimated as at least 4 to 12 years to evaluate the ability of any putative prophylactic therapy to decrease, arrest, or reverse abnormalities in Abeta42 metabolism many years before clinical symptoms of Alzheimer disease are otherwise likely to occur.

Adult↗
PubMed2000

Familial Alzheimer's disease: site of mutation influences clinical phenotype.

Alzheimer's disease (AD) is caused by multiple genetic and/or environmental etiologies. Because differences in the genetically determined pathogenesis may cause differences in the phenotype, we examined age at onset and age at death in 90 subjects with dominantly inherited AD due to different mutations (amyloid precursor protein, presenilin-1, and presenilin-2 genes). We found that among patients with dominantly inherited AD, genetic factors influence both age at onset and age at death.

Adult↗
PubMed1999

Predictive value of the intracarotid amobarbital test in bihemispheric seizure onset.

The intracarotid amobarbital test (IAT) is used to lateralize language function and assess hemispheric memory. In this study 23 non-lesional epileptic patients were evaluated. The magnitude of the difference in IAT scores between the two hemispheres was significantly greater in the patients whose seizures lateralized on scalp or intracranial EEG than in patients with bihemispheric seizure onset. This suggests that the IAT is useful not only in predicting lateralized seizure focus, but bihemispheric onset as well.

Adult↗
PubMed1998

Delayed recall in dementia: sensitivity and specificity in patients with higher than average general intellectual abilities.

OBJECTIVE: Distinguishing early dementia from normal aging is especially difficult in patients with higher than average intellectual abilities. To find signs useful in determining that the elderly "worried and well" are not in an early phase of dementia, we compared the neuropsychological test performance of demented patients, patients who were not found to be demented, and control subjects. METHOD: A retrospective study of neuropsychological test results from persons over 50 years of age who had an age-adjusted verbal intelligence quotient (VIQ) greater than or equal to 110. Analysis of covariance (using age and education as covariates) was used to compare the normal, no dementia, and dementia groups. Significant differences were further analyzed using Tukey's post hoc procedure. Tests on which the three groups differed at ap < 0.01 level were included in multivariate analyses. RESULTS: The no dementia patient group performed at functional levels comparable to those of the control group. By contrast, patients with dementia showed significant impairment on tests of memory, naming, and visuospatial function compared with both the control and no dementia groups. Immediate and delayed paragraph recall classified groups with a 96% specificity and 80% sensitivity in the multivariate discriminant analysis. CONCLUSIONS: These results suggest that in patients with higher than average intelligence, the absence of a significant dementing process (as well as its presence) can be determined with reasonable probability.

Aged↗
PubMed1997

A topographic study of ERPs elicited by visual feature discrimination.

The functional properties and topographic distribution of event-related potential (ERP) components elicited by visual discrimination of orientation, spatial frequency, spatial location, and color were investigated. ERPs were recorded from 28 electrode sites from 16 adult subjects. Five ERP components were measured: N1 (peak latency = 160 ms), P2 (250 ms), anterior N2 (260 ms), posterior N2 (280 ms), and P3 (400 ms). N1 and P2 were more negative when a stimulus was a target, showing the selection negativity effect. Feature-specific effects on component amplitude or topography varied by component. N1 and P2 were sensitive to stimulus orientation and location. Anterior or posterior N2 was sensitive to orientation, spatial frequency, and location. P3 varied with orientation, but not with other stimulus features. Cross-task comparisons of ERPs to vertical line segments in the color, orientation, and location discrimination tasks indicated that P2 and N2, but not N1 and P3, were sensitive to changes in task-demand. These data provide topographic evidence that ERP components in the 160-400 ms time domain can be differentiated on the basis to processing of specific visual features, and reflect neurophysiologically distinct visual pathways in the human cortex.

Adult↗
PubMed1996

Screening for dementia: Cognitive Assessment Screening Test (CAST).

The Cognitive Assessment Screening Test (CAST) is a self-administered paper-and-pencil test that can be used to screen geriatric patients for dementia. The test is composed of three one-page sections; Part A has 10 simple questions; Part B has five more demanding questions, and Part C has 13 self-report questions. Parts A and B determine whether cognition falls within the normal range or below the threshold for dementia. Part C assesses the patient's perception of a decline in memory and competence. Designed for office use, the CAST requires minimal examiner time and little training or experience to administer. This test is as sensitive and specific as other relatively brief screening instruments for dementia.

Aged↗
PubMed1996

Behavioral slowing with age: boundary conditions of the generalized slowing model.

One hundred and twenty-two adults ranging in age from 20 to 83 years participated in this study of visual discrimination and recognition. The simultaneous-matching-to-sample (discrimination) and delayed-matching-to-sample (recognition) paradigms used identical stimuli for spatial frequency, luminance, spatial localization, orientation, pattern, trajectory, and velocity matching. Linear regression analyses indicated that increased age slowed reaction time on the simultaneous-matching tasks. This relationship was not found, however, when subjects were required to match the stimuli after a delay. When older adults' reaction times were regressed on those of adults in their 20s, very different patterns of age-related slowing emerged from the data as a function of task requirements. The results from the simultaneous-matching paradigm replicate previous reports of general slowing on nonlexical tasks, but this was not true for the results from the delayed-matching paradigm, which used similar stimuli but also involved short-term memory.

Adult↗
PubMed1996

Selective deficits in visual perception and recognition in schizophrenia.

OBJECTIVE: The purpose of this study was to evaluate the performance of patients with schizophrenia on tests of visual discrimination and recognition of different stimulus features. METHOD: Thirteen medicated male schizophrenic patients and 13 normal comparison subjects were tested on four stimulus features: spatial frequency, pattern, location, and trajectory. Subjects had to make both discrimination and recognition judgments at three levels of stimulus disparity. RESULTS: The responses of the patient group were slower and less accurate than those of the comparison group on both the discrimination and recognition tasks. The patients were less accurate than the comparison subjects in processing spatial features of the stimuli, particularly trajectory, but were unimpaired in processing form attributes (high spatial frequencies and patterns). When the results of pattern and trajectory tasks were matched against the accuracy performance of the comparison group, the patients were less accurate on trajectory than on pattern judgments and less accurate on recognition than on discrimination performance. CONCLUSIONS: Schizophrenia may be accompanied by impaired visual spatial perception and representation. In schizophrenia, deficits in trajectory discrimination may reflect a disturbance of the dorsal pathway of the visual system, while disturbances of trajectory recognition performance may reflect a deficit in prefrontal systems involved in visual working memory operations.

Adult↗
PubMed1996

Rate of progression in familial Alzheimer's disease.

The clinical course of early-onset, dominantly inherited, familial Alzheimer's disease (FAD) was contrasted with late-onset, sporadic Alzheimer's disease (AD). Eight FAD and 23 sporadic AD patients were followed over a mean of 63 months from estimated disease onset. The two groups did not differ notably in duration of symptoms from onset, global disease severity, or degree of cognitive deficits on initial evaluation. The Kaplan-Meier lifetable method was used to assess time from estimated disease onset to dependence in self-care, institutionalization, and death. A greater percentage of FAD patients became dependent in self-care and died earlier than did sporadic AD patients. The lifetable results suggest that FAD may have a more rapid course than dose late-onset sporadic AD.

Activities of Daily Living↗
PubMed1996

The cognitive assessment screening test (CAST) for dementia.

The purpose of this study was to assess the usefulness, the sensitivity, and the specificity of the Cognitive Assessment. Screening Test (CAST), a paper-and-pencil self-administered cognitive test designed to screen elderly people for possible dementia, for use in general physicians' offices, requiring little expertise or staff time. CAST consists of three parts: part A (relatively easy), part B (more demanding), and part C (self-report of concerns). CAST was administered in two studies to: (1) 19 patients known to be mildly to moderately demented versus 24 age-matched normal controls (to establish cutoff standards); and (2) a "real world" sample of 26 elderly patients not known to be demented, attending a general medicine clinic. The sensitivity and specificity of CAST were compared with the Mini-Mental State Examination (MMSE) and the Blessed Dementia Scale cognitive portion (BDS-cog). In study 1, controls were given a detailed neuropsychological battery; in study 2, all patients were given the neuropsychological battery, which served as the "gold standard" to identify individuals with cognitive impairment. In study 1, the cutoff scores for dementia using CAST (Parts A and B) were established. CAST discriminated demented patients from controls with a sensitivity of 95% and a specificity of 88%; the MMSE had a sensitivity of 74% and a specificity of 100%; and the BDS-cog had a sensitivity of 100% and a specificity of 96%. In study 2, CAST discriminated cognitive impairment with a sensitivity of 88% and a specificity of 100%, the MMSE had a sensitivity of 38% and a specificity of 100%; and the BDS-cog had a sensitivity of 50% and a specificity of 94%. Part C was not used to discriminate demented from normal elderly individuals, but to screen for those concerned about their cognitive functioning. CAST is highly useful as a dementia screening test, with sensitivity and specificity equal to or better than the MMSE and BDS-cog, yet requiring minimal examiner time and little training or experience to administer.

Aged↗
PubMed1996

Familial and sporadic Alzheimer's disease: neuropathology cannot exclude a final common pathway.

Whether all etiologic forms of Alzheimer's disease (AD) share a final common pathway is a major issue. We determined the severity and regional distribution of neuronal loss, amyloid plaques, neuritic plaques (NPs), and neurofibrillary tangles (NFTs), and calculated the ratio of neuronal loss to NPs and NFTs in brains of 19 familial AD (FAD) patients with linkage to chromosome 14, six AD patients with mutations of chromosome 21 (codon 717 of the beta-amyloid percursor protein gene), and 11 sporadic AD (SAD) patients. There was no difference in the pattern of distribution of the various pathologic features or in the ratio of neuronal loss to NPs or NFTs in any AD group. However, FAD groups could be distinguished from SAD by the greater severity and the lack of influence of apolipoprotein E genotype on pathology. These differences may reflect differences in age at onset rather than different etiopathologic mechanisms. The similarity of pathologic findings in the different AD groups provides evidence for a final common pathophysiologic pathway in AD.

Age of Onset↗
PubMed1994

Alzheimer's disease and Lewy body disease: a comparative clinicopathological study.

The exact nature of the relationship between Lewy body disease and Alzheimer's disease (AD) is unknown. To investigate this, we compared cases of pure Lewy body disease, mixed Lewy body disease with AD, and pure AD to see what pathological features were shared and how they differed. We counted neurons, Lewy bodies, diffuse and neuritic senile plaques, neurofibrillary tangles, and neuropil threads in the frontal and medial temporal cortex and hippocampus from 5 autopsied cases of Lewy body disease (without AD histopathology), 7 with combined Lewy body disease and AD, 6 with AD, and 5 age-matched normal control subjects. Average neuronal counts in the cases with Lewy body disease were indistinguishable from those of control subjects, but higher than those for AD and combined Lewy body disease and AD. Diffuse plaque densities were similar in all disease forms. Neuritic senile plaques, neurofibrillary tangles, and neuropil threads were numerous in AD and combined Lewy body disease and AD, but sparse or absent in Lewy body disease and controls. Pure Lewy body disease and AD appear to be distinct clinicopathological entities except for the common feature of diffuse plaques in both disorders.

Aged↗
PubMed1993

Driving and Alzheimer's disease: the risk of crashes.

We designed this questionnaire-based study to determine the risk of auto crashes among Alzheimer's disease (AD) patients who continued to drive after the onset of AD, compared with normal age-matched control subjects and other drivers' statistical records. While ultimately all AD patients will become incapable of driving, it is not known whether, under current licensing regulations and self-imposed limitations, patients with AD present a definably increased risk of being involved in crashes, and if so, the relative magnitude of the risk and at what point in the course of the disease the risk may become significantly increased. We administered a brief questionnaire to the caregivers of 130 AD patients and to 112 age-matched, nondemented control subjects and their spouses. Annual rates of occurrence and severity of all crashes, and of crashes reported to the authorities, were determined from spousal or other caregiver responses. For all years of driving following the onset of dementia, AD patients had a mean of 0.091 reported crashes per year compared with matched controls, who had an average of 0.040 reported crashes per year in the same period of time. The average number of crashes per year changed with each year of driving following the onset of AD, with considerably lower reported crash rates during the initial years of dementia: in year 1, the crash rate was 0.068; in year 2, 0.097; in year 3, 0.093; in year 4, 0.159; in year 5 and beyond, 0.129.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1992

Neuropsychological features of familial Alzheimer's disease.

It has been proposed that early-onset familial Alzheimer's disease (FAD) and sporadic Alzheimer's disease (AD) have different causes, with FAD due to a single dominant gene with disease onset before the sixth decade, whereas sporadic AD has a later onset and is not associated with a dominant pattern of inheritance. Given these differences, we questioned whether these etiologically distinct forms of AD also differ neuropsychologically. In this study we performed neuropsychological evaluations on patients from two well-documented families with FAD and a group of patients with sporadic AD. The groups were matched on global disease severity at entry. Two groups of education- and age-matched normal controls were recruited for comparison. The groups were analyzed for psychometric findings and pattern of deficits. Both patients with FAD and patients with sporadic AD showed a similar pattern of neuropsychological impairment relative to age-matched controls, i.e., mildly to moderately impaired verbal performance and concentration, severely slowed psychomotor speed, and severely impaired delayed recall of verbal material. There were no differences in pattern suggestive of disproportionately severe anomia, amnesia, agnosia, or apraxia in the early onset FAD group, as has been reported previously.

Adult↗
PubMed1992

Active and passive P3 latency and psychometric performance: influence of age and individual differences.

The relationship of P3 latency of the event-related potential (ERP) to psychometric performance was investigated in 41 subjects who ranged in age from 20 to 88 years. P3 responses were recorded from subjects using an auditory oddball paradigm with and without task-demands. Subjects also received psychometric tests of verbal performance, visuospatial performance, concentration, and immediate, recent and remote memory. Factor analysis was used to reduce the set of psychometric measures to four factors (Verbal learning, general intelligence, narrative recall/fluency, and concentration). Both passive and active P3 latency showed a linear increase with age. Age was inversely correlated with verbal learning performance. After accounting for the influence of age, passive P3 latency correlated with the psychometric factor associated with narrative recall and verbal fluency. Active P3 latency was correlated with factors reflecting general intelligence and concentration. These findings suggest that cognitive processing speed contributes to psychometric performance in adults. The psychological or biological basis for this relationship remains to be identified.

Adult↗
PubMed1992

The Caretaker Obstreperous-Behavior Rating Assessment (COBRA) Scale.

OBJECTIVE: To evaluate the usefulness and reliability of the Caretaker Obstreperous-Behavior Rating Assessment (COBRA), a new test instrument for caretaker assessment of types and severity of "obstreperous behaviors" (OBs) in demented patients. DESIGN: COBRA was completed by caretakers of 31 outpatients and 36 nursing home inpatients with dementia. Test-retest reliability was determined when 25 of the outpatient caretakers re-evaluated their demented relative 1 week later; inter-rater reliability was determined on nursing home inpatients by comparing the reports of two nurse's aids with equivalent knowledge of seven of the patients. SETTING: (1) University medical center Alzheimer's Disease and Related Disorders Clinic; (2) community nursing home. PATIENTS: Thirty-one sequentially-seen outpatients with dementia; 36 nursing home patients with dementia. INTERVENTION: Following instruction in the use of the COBRA Scale, caretakers provided scores for their demented patient. The instrument has three unique features: (1) it divides OBs into four categories for ease of comprehension: Aggressive/Assaultive; Mechanical/Motor; Ideational/Personality; and Vegetative; (2) a companion videotape shown to caretakers in advance illustrates each behavior to improve reliability of reporting; (3) the significance of each OB is estimated with severity and frequency measures. MAIN OUTCOME MEASUREMENTS: Frequency and severity of OBs are epitomized in 12 summary scores. Test-retest correlations (for outpatients) and inter-rater correlations (for inpatients) were analyzed with Pearson Product Moment and Spearman Rank Order correlations. RESULTS: Prevalence of OBs and severity was reported for the experimental groups. Summary scores revealed test-retest correlations of .95 to .73 for 11 of 12 scores (outpatients), and inter-rater correlations of .99 to .73 for 8 of 12 scores (inpatients). Age, gender, and disease etiology were not significantly related to OBs; clinical severity correlated with type and severity of OBs. CONCLUSIONS: The COBRA scale provides a convenient, comprehensive, and reliable means for caretakers to identify the types and measure the severity of OBs in demented outpatients and nursing home inpatients. If additional studies confirm these observations, COBRA will be a useful instrument for assessing the effects of interventions on OBs in patients with dementia.

Aged↗