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Biomedical subjects

M S Albert

Publications and source records attributed to M S Albert.

At least 55 records · Page 3Linked to original sources
PubMed1997

Education and other measures of socioeconomic status and risk of incident Alzheimer disease in a defined population of older persons.

OBJECTIVE: To assess the relations of 3 measures of socioeconomic status (education, occupational prestige, and income) to risk of incident clinically diagnosed Alzheimer disease (AD). DESIGN: Cohort study with an average observation of 4.3 years. SETTING: East Boston, Mass. a geographically defined community. PARTICIPANTS: A stratified random sample of 642 community residents 65 years of age and older who were free of AD at baseline. MAIN OUTCOME MEASURE: Clinical diagnosis of probable AD according to standard criteria, using structured uniform evaluation. RESULTS: The relations of the 3 measures of socioeconomic status to risk of disease were assessed using logistic regression analyses. In individual analyses, fewer years of formal schooling, lower income, and lower occupational status each predicted risk of incident AD; risk of disease decreased by approximately 17% for each year of education. In an analysis including all 3 measures, the effect of education on risk for disease remained approximately the same, but the effects of the other 2 measures were somewhat less and did not attain formal statistical significance, compared with separate analysis of each measure. CONCLUSIONS: Markers of lower socioeconomic status predict risk of developing incident AD. The mechanism of this relation is uncertain, but the possibility that it reflects unidentified and potentially reversible risk factors for the disease deserves careful investigation.

Aged↗
PubMed1997

Development and validation of a Structured Telephone Interview for Dementia Assessment (STIDA): the NIMH Genetics Initiative.

As part of the NIMH Genetics Initiative Alzheimer's Disease (AD) Study Group, a brief structured telephone interview to distinguish individuals with normal cognitive functioning from those with changes in cognition and daily functioning suggestive of early AD was developed. The Structured Telephone Interview for Dementia Assessment (STIDA), yields a dementia score between 0 and 81 (higher scores indicating greater impairment). Subscales corresponding to the subscales of the Clinical Dementia Rating Scale (CDR) can be derived. The STIDA performed well as a screening instrument for mildly demented individuals. When a score of 10 or more (based on informant interview and subject testing) was used to identify mildly impaired individuals, the STIDA had a sensitivity of .93 and a specificity of .92 for a clinician-derived CDR of 0.5 or more. The STIDA was also capable of accurately assessing the level of dementia. STIDA-derived CDR ratings agreed with clinician-derived CDR scores in 23 of 28 cases, corresponding to an unweighted kappa of.71 and a weighted kappa of.81. A much-abbreviated short STIDA that could be administered directly to the subject was able to detect possible impairment with a sensitivity of .93 and a specificity of.77. These results suggest that the short STIDA provides a sensitive and fairly specific telephone screen for dementia, and that the full STIDA, consisting of an interview with a knowledgeable informant and subject testing, approximates the success of a face-to-face clinical interview, and provides reliable and valid screening and staging of dementia over the telephone.

Aged↗
PubMed1997

Increase in urinary cortisol excretion and memory declines: MacArthur studies of successful aging.

Cortisol production is increased during stress, and the actions of cortisol on receptors in the brain and other body organs are involved in allostasis, the process of adaptation to stress, as well as in allostatic load, the wear and tear associated with excessive exposure to cortisol. Using data from a community-based longitudinal study of older men and women, aged 70-79 yr, we tested the hypothesis that exposure to increasing levels of cortisol is associated with declines in memory performance. Associations between 12-h urinary free cortisol excretion and performance on tests of memory (delayed verbal recall and spatial recognition), abstraction, and spatial ability were examined. Among the women, greater cortisol excretion was associated with poorer baseline memory performance, independent of socio-demographic, health status, health behavior, and psychosocial characteristics. Moreover, women who exhibited increases in cortisol excretion over a 2.5-yr follow-up period were more likely to show declines in memory performance. By contrast, women who experienced declines in cortisol exhibited improvements in memory performance. No significant associations were found among the men. The results for the women suggest that decrements in memory performance associated with increases in cortisol may not represent irreversible effects, as declines in cortisol were associated with improvements in memory.

Aged↗
PubMed1997

ApoE-4 and age at onset of Alzheimer's disease: the NIMH genetics initiative.

OBJECTIVE: To explore the impact of apoE-4 on Alzheimer's disease (AD) and its age at onset. DESIGN: A genetic linkage study using affected relative pairs, predominantly siblings. SETTING: Three academic medical centers ascertained subjects from memory disorder clinics, nursing homes, and the local community. SUBJECTS: 310 families including 679 subjects with AD by NINCDS/ADRDA and/or Khachaturian criteria and 231 unaffected subjects. OUTCOME MEASURE: ApoE genotype. ANALYTIC METHODS: Association, affected pedigree member, sibling pair, and lod score analyses. RESULTS: ApoE-4 was strongly associated with AD in this sample (allele frequency = 0.46 vs. 0.14 in controls, p < 0.000001). Results of lod score, affected pedigree member analysis, and sib-pair analysis also supported apoE-4 as a risk factor for AD. When the sample was stratified on family mean age at onset, the risk conferred by apoE-4 was most marked in the 61 to 65 age group. Individuals with two copies of apoE-4 had a significantly lower age at onset than those with one or no copies (66.4 vs. 72.0, p < 0.001), but individuals with one copy did not differ from those with none. Within families, the individual with the earliest age at onset had, on average, significantly more apoE-4 alleles (p < 0.0001) than the individual with the latest onset. DISCUSSION: This work supports previous reports of an association between apoE-4 and the development of AD and demonstrates that apoE-4 exerts its maximal effect before age 70. These findings have important implications for the potential use of apoE genotyping for diagnosis and prediction of disease. They also underscore the need to identify additional genetic factors involved in AD with onset beyond age 70 years.

Age of Onset↗
PubMed1996

Cognitive and neurobiologic markers of early Alzheimer disease.

Recent studies indicate that impairments in two cognitive domains characterize the cognitive abnormalities that appear earliest in the course of Alzheimer disease (AD). These cognitive domains pertain to memory and executive function ability; in particular, memory test scores reflecting the difference between immediate and delayed recall and tasks that assess cognitive flexibility (e.g., set-shifting). Preliminary data indicate that tasks of this nature, along with specific genetic information (i.e., APOE-4 status), are important in identifying which individuals with recent cognitive changes (considered to have "questionable" disease) will progress to the point where they meet criteria for AD over time. When this cognitive and genetic information is combined with neuroimaging measures targeted at the brain regions demonstrating pathology early in AD, it may serve as specific and accurate prognostic markers of AD.

Alcohol Amnestic Disorder↗
PubMed1996

Cognitive deficits in patients with chronic fatigue syndrome.

Twenty-nine subjects with chronic fatigue syndrome (CFS) and 25 healthy control subjects were administered a lengthy neuropsychological battery that included standard neuropsychological tests and a computerized set of tasks that spanned the same areas of ability. The primary significant differences between patients and controls were found on tests of learning and memory. These differences remained when the degree of psychiatric symptomatology in the subjects was covaried. Patients on and off psychoactive medications did not differ in their performance on these tasks. These results suggest that at least a subset of CFS patients may experience significant impairments in learning and memory.

Adult↗
PubMed1996

The role of hippocampus and frontal cortex in age-related memory changes: a PET study.

The purpose of this study was to examine the neuroanatomical correlates of explicit retrieval of episodic memories in older and young adults. We used an experimental paradigm that allowed us to separate the effort involved in attempting to retrieve a recently studied word from the actual recollection of the item. Both older and younger adults showed hippocampal blood flow increases in association with recollection of a studied word. In contrast, younger but not older adults showed bilateral blood flow increases in anterior prefrontal cortex during retrieval attempts: older adults showed more posterior frontal lobe activations during attempted retrieval. We conclude that the hippocampus activations may reflect a commonality in the way that older and younger adults remember past events, whereas differences in frontal activation may reflect age-related changes in their retrieval strategies.

Adult↗
PubMed1996

Conscious recollection and the human hippocampal formation: evidence from positron emission tomography.

We used positron emission tomography (PET) to examine the role of the hippocampal formation in implicit and explicit memory. Human volunteers studied a list of familiar words, and then they either provided the first word that came to mind in response to three-letter cues (implicit memory) or tried to recall studied words in response to the same cues (explicit memory). There was no evidence of hippocampal activation in association with implicit memory. However, priming effects on the implicit memory test were associated with decreased activity in extrastriate visual cortex. On the explicit memory test, subjects recalled many target words in one condition and recalled few words in a second condition, despite trying to remember them. Comparisons between the two conditions showed that blood-flow increases in the hippocampal formation are specifically associated with the conscious recollection of studied words, whereas blood-flow increases in frontal regions are associated with efforts to retrieve target words. Our results help to clarify some puzzles concerning the role of the hippocampal formation in human memory.

Adult↗
PubMed1996

Determinants of tissue delivery for 129Xe magnetic resonance in humans.

Magnetic resonance imaging using laser-polarized 129Xe is a new technique first demonstrated by Albert et. al. (Nature 370, 1994) who obtained a 129Xe image of an excised mouse lung. This paper describes the factors influencing the accumulation of inhaled, polarized 129Xe in human tissue. The resulting model predicts the 129Xe magnetization in different tissues as a function of the time from the start of inhalation, the tissue perfusion rate and partition coefficient for xenon, and the relevant T1 decay times. The relaxation times of 129Xe in biological tissues are not yet known precisely. Substitution of estimated values for these parameters results in an expected signal-to-noise ratio (SNR) from polarized 129Xe MR in the brain of approximately 2% of the equivalent SNR from proton MR.

Brain↗
PubMed1996

Impaired awareness of deficits in Alzheimer disease.

This study examined the relation between awareness of memory and functional decline and cognitive function in patients with Alzheimer disease (AD). Twenty-six patients with early AD and 16 nondemented elderly controls were studied. Awareness of deficits was determined by using (a) a discrepancy score between subject's and caregiver's ratings on a memory questionnaire, (b) a discrepancy score between subject's and caregiver's ratings on an activities-of-daily-living scale, and (c) a clinical rating of dementia awareness for patients. Whereas self-ratings of memory and activities of daily living were not significantly different between AD patients and controls, these two measures differed significantly when AD patients' ratings were compared with those of their caregivers. Measures of awareness of deficits correlated with one another and were primarily associated with performance on tests of executive and visuospatial functions but not with depression. Early AD is characterized by a failure of self-monitoring. Deficits in self-monitoring have been proposed to occur after damage to the frontal lobes and other cerebral areas. Impaired awareness of memory and functional deficits in AD is related to cognitive impairments, which may involve frontal and right hemisphere connections.

Aged↗
PubMed1996

Neurobiological bases of age-related cognitive decline in the rhesus monkey.

The rhesus monkey offers a useful model of normal human aging because when monkeys are tested on a battery of behavioral tasks that can also be used to evaluate cognition in humans, it is found that the monkeys undergo an age-related decline in several domains of cognitive function as do humans. In monkeys these changes begin at about 20 years of age. To determine what gives rise to this cognitive decline, we have examined several parameters in the brains of monkeys. Some parameters do not change with age. Examples of this are the numbers of neurons in the neocortex and hippocampal formation, and the numbers of synapses in the hippocampal formation. Changes in other parameters can be positively correlated with chronological age; examples of this are numbers of neuritic plaques, a decrease in the numbers of neurons in the striatally projecting pars compacta of the substantia nigra, and a decrease in the thickness of layer I in primary visual cortex. But the most interesting changes are those that correlate either with cognitive decline alone, or with both cognitive decline and chronological age. Among these are a breakdown in the integrity of myelin around axons, an overall reduction in the volume of white matter in the cerebral hemispheres, thinning of layer I in area 46 of prefrontal cortex, and decreases in the cell density in cortically projecting brain stem nuclei. To date then, our studies suggest that the cognitive declines evident in the rhesus monkey may be a consequence of changes in layer I and in the integrity of myelinated axons, rather than an age-related loss of cortical neurons or synapses, as has long been assumed.

Aging↗
PubMed1996

Recall and recognition memory in obsessive-compulsive disorder.

This study examined recall and recognition memory in 20 nonmedicated patients with obsessive-compulsive disorder (OCD) and 20 matched control subjects. As hypothesized, OCD subjects showed abnormalities affecting delayed recall of nonverbal information but showed normal recognition. These results are interpreted as providing preliminary evidence of a nonverbal memory retrieval deficit consistent with proposed corticostriatal system dysfunction in OCD.

Adult↗
PubMed1996

Intracranial compartment volumes in patients with enlarged ventricles assessed by magnetic resonance-based image processing.

Magnetic resonance image-based computerized segmentation was used to measure the volumes of the brain, gray and white matter components, and to identify regions with prolonged enhancement on T2-weighted imaging, such as periventricular or deep white matter hyperintensities. The authors also determined the volumes of the ventricles and subarachnoid space in control subjects and in patients with: 1) aqueductal stenosis (AS); 2) other causes of obstructive hydrocephalus (OH); 3) Alzheimer's disease (AD); and 4) normal-pressure hydrocephalus (NPH). In AS the volume of the brain was smaller, whereas that of ventricles and subarachnoid cerebrospinal fluid space was larger than that of controls. The decrease in brain volume was due primarily to white matter loss. Although in OH the ventricles were larger, the subarachnoid space was smaller than in controls, presumably due to encroachment by the brain, in which the volume remained unchanged. In AD, loss of both gray and white matter resulted in a smaller brain volume, whereas that of ventricles and subarachnoid space was larger than in controls. In NPH patients, only ventricular volume was greater, whereas all other compartments were similar to controls. The brain normally occupies 87% to 92% of the intracranial volume and consequently, as observed in our patients, relatively small decrements in brain size lead to large increments in ventricular and/or extraventricular volumes. The magnitude of such changes differed markedly among our patient groups, and whether such changes prove useful in clinical assessment and differentiation needs to be determined.

Adult↗
PubMed1996

Age-related changes in intracranial compartment volumes in normal adults assessed by magnetic resonance imaging.

Magnetic resonance (MR) image-based computerized segmentation was used to measure various intracranial compartments in 49 normal volunteers ranging in age from 24 to 80 years to determine age-related changes in brain, ventricular, and extraventricular cerebrospinal fluid (CSF) volumes. The total intracranial volume (sum of brain, ventricular, and extraventricular CSF) averaged 1469 +/- 102 cm3 in men and 1289 +/- 111 cm3 in women. The difference was attributable primarily to brain volume, which accounted for 88.6% of the respective intracranial volumes in both sexes, but was significantly larger in men (1302 +/- 112 cm3) than in women (1143 +/- 105 cm3). In both, the cranial CSF volume averaged 11.4%. Total intracranial volume did not change with age, although the normalized brain volume of both men and women began to decrease after the age of 40 years. This decrease was best reflected by expansion of the extraventricular CSF volume which, after the age of 50 years, was more marked in men than in women. The volume of the cranial CSF, as determined by MR image-based computerized segmentation, is considerably larger than traditionally accepted and resides mostly extraventricularly. Expansion of CSF volume with age provides a good index of brain shrinkage although evolving changes and growth of the head with age tend to confound the results.

Adult↗