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Biomedical subjects

Barry Reisberg

Publications and source records attributed to Barry Reisberg.

13 recordsLinked to original sources

Mild cognitive impairment.

Mild cognitive impairment is a syndrome defined as cognitive decline greater than expected for an individual's age and education level but that does not interfere notably with activities of daily life. Prevalence in population-based epidemiological studies ranges from 3% to 19% in adults older than 65 years. Some people with mild cognitive impairment seem to remain stable or return to normal over time, but more than half progress to dementia within 5 years. Mild cognitive impairment can thus be regarded as a risk state for dementia, and its identification could lead to secondary prevention by controlling risk factors such as systolic hypertension. The amnestic subtype of mild cognitive impairment has a high risk of progression to Alzheimer's disease, and it could constitute a prodromal stage of this disorder. Other definitions and subtypes of mild cognitive impairment need to be studied as potential prodromes of Alzheimer's disease and other types of dementia.

Aged↗

A 24-week open-label extension study of memantine in moderate to severe Alzheimer disease.

BACKGROUND: This study is an extension of a 28-week, randomized, double-blind, placebo-controlled study of memantine in 252 patients with moderate to severe Alzheimer disease. OBJECTIVE: To evaluate long-term memantine treatment in moderate to severe Alzheimer disease. DESIGN, SETTING, AND PATIENTS: Open-label, 24-week extension trial. Raters remained blind to the patients' initial study treatment. Patients (n = 175) were enrolled from the previous double-blind study in an outpatient setting. INTERVENTION: Twenty mg of memantine was given daily. MAIN OUTCOME MEASURES: Efficacy assessments from the double-blind study were continued and safety parameters were monitored. RESULTS: Patients who switched to memantine treatment from their previous placebo therapy experienced a significant benefit in all main efficacy assessments (functional, global, and cognitive) relative to their mean rate of decline with placebo treatment during the double-blind period (P<.05). The completion rate for the extension phase of the study was high (78%) and the favorable adverse event profile for memantine therapy was similar to that seen in the double-blind study. CONCLUSION: These results extend previous findings that demonstrated the efficacy and safety of memantine in the treatment of patients with moderate to severe Alzheimer disease.

Aged↗

Diagnostic criteria in dementia: a comparison of current criteria, research challenges, and implications for DSM-V.

Planning is being initiated for the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders 5th ed. (DSM-V). Therefore, the dementia diagnosis criteria in the American Psychiatric Association's DSM-IV-TR (4th ed, text revision, 2000) have been compared with the World Health Organization's International Classification of Diseases (10th revision, 1992). Critiques are based primarily on (a) internal consistency and validity of the classification, (b) historical development of the field, (c) conclusions of consensus conferences, and (d) current knowledge and practice. It is suggested that (1) the entire category be labeled "cognitive disorders," to better characterize this group of disorders, (2) there is no longer any scientific basis for the presenile versus senile dementia dichotomy at age 65, (3) Alzheimer's disease no longer should have unique status as a "diagnosis of exclusion," (4) future manuals should incorporate knowledge regarding the clinical manifestation and course of Alzheimer's disease and other dementias, and (5) the classification "Pick's disease" should be broadened to "frontotemporal dementias." DSM-V should incorporate continuing advances in the neuroscience knowledge base and understanding of these disorders.

Aged↗

Diffusion tensor imaging of frontal white matter microstructure in early Alzheimer's disease: a preliminary study.

Several investigators have suggested that the pathological progression of Alzheimer's disease appears to recapitulate the developmental maturation pattern, a process termed retrogenesis. Diffusion tensor imaging was used to test the hypothesis that the microstructural integrity of superior frontal and temporal white matter, one of the last regions to mature, would be reduced in vivo in early Alzheimer's disease. Five consecutive slices, from the orbitofrontal to periventricular frontal regions, as well as temporal and corpus callosal white matter regions, were sampled. Fractional anisotropy, mean diffusivity, axial diffusion, and radial diffusion of 10 patients with early Alzheimer's disease and 10 age-similar healthy control subjects were compared. Patients with Alzheimer's disease were found to have significantly reduced fractional anisotropy, increased mean diffusivity, and increased radial diffusion in superior frontal white matter. These data suggest that the integrity of periventricular frontal white matter rather than orbitofrontal white matter appears to be altered in early Alzheimer's disease and that the white matter abnormalities involve compromised myelin, consistent with the retrogenesis theory.

Aged↗

Cell type- and brain structure-specific patterns of distribution of minibrain kinase in human brain.

The minibrain kinase (Mnb/Dyrk1A) gene is localized in the Down syndrome (DS) critical region of chromosome 21. This gene encodes a proline-directed serine/threonine protein kinase (minibrain kinase-Mnb/Dyrk1A), which is required for the proliferation of distinct neuronal cell types during postembryonic neurogenesis. To study the distribution of Mnb/Dyrk1A during human brain development and aging, we raised Mnb/Dyrk1A-specific antibody (mAb 7F3) and examined 22 brains of normal subjects from 8 months to 90 years of age. We found that neurons were the only cells showing the presence of 7F3-positive product in both cell nucleus and cytoplasm. Nuclear localization supports the concept that Mnb/Dyrk1A may be involved in control of gene expression. Synaptic localization of Mnb/Dyrk1A also supports our previous studies suggesting that Mnb/Dyrk1A is a regulator of assembly of endocytic apparatus and appears to be involved in synaptic vesicle recycling and synaptic signal transmission. Accumulation of numerous 7F3-positive corpora amylacea in the memory and motor system subdivisions in subjects older than 33 years of age indicates that Mnb/Dyrk1A is colocalized with markers of astrocyte and neuron degeneration. Differences in the topography and the amount of Mnb/Dyrk1A in neurons, astrocytes, and ependymal and endothelial cells appear to reflect cell type- and brain structure-specific patterns in trafficking and utilization of Mnb/Dyrk1A.

Adult↗

Memantine in moderate-to-severe Alzheimer's disease.

BACKGROUND: Overstimulation of the N-methyl-D-aspartate (NMDA) receptor by glutamate is implicated in neurodegenerative disorders. Accordingly, we investigated memantine, an NMDA antagonist, for the treatment of Alzheimer's disease. METHODS: Patients with moderate-to-severe Alzheimer's disease were randomly assigned to receive placebo or 20 mg of memantine daily for 28 weeks. The primary efficacy variables were the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) and the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory modified for severe dementia (ADCS-ADLsev). The secondary efficacy end points included the Severe Impairment Battery and other measures of cognition, function, and behavior. Treatment differences between base line and the end point were assessed. Missing observations were imputed by using the most recent previous observation (the last observation carried forward). The results were also analyzed with only the observed values included, without replacing the missing values (observed-cases analysis). RESULTS: Two hundred fifty-two patients (67 percent women; mean age, 76 years) from 32 U.S. centers were enrolled. Of these, 181 (72 percent) completed the study and were evaluated at week 28. Seventy-one patients discontinued treatment prematurely (42 taking placebo and 29 taking memantine). Patients receiving memantine had a better outcome than those receiving placebo, according to the results of the CIBIC-Plus (P=0.06 with the last observation carried forward, P=0.03 for observed cases), the ADCS-ADLsev (P=0.02 with the last observation carried forward, P=0.003 for observed cases), and the Severe Impairment Battery (P<0.001 with the last observation carried forward, P=0.002 for observed cases). Memantine was not associated with a significant frequency of adverse events. CONCLUSIONS: Antiglutamatergic treatment reduced clinical deterioration in moderate-to-severe Alzheimer's disease, a phase associated with distress for patients and burden on caregivers, for which other treatments are not available.

Activities of Daily Living↗

Vascular cognitive impairment.

Cerebrovascular disease is the second most common cause of acquired cognitive impairment and dementia and contributes to cognitive decline in the neurodegenerative dementias. The current narrow definitions of vascular dementia should be broadened to recognise the important part cerebrovascular disease plays in several cognitive disorders, including the hereditary vascular dementias, multi-infarct dementia, post-stroke dementia, subcortical ischaemic vascular disease and dementia, mild cognitive impairment, and degenerative dementias (including Alzheimer's disease, frontotemporal dementia, and dementia with Lewy bodies). Here we review the current state of scientific knowledge on the subject of vascular brain burden. Important non-cognitive features include depression, apathy, and psychosis. We propose use of the term vascular cognitive impairment, which is characterised by a specific cognitive profile involving preserved memory with impairments in attentional and executive functioning. Diagnostic criteria have been proposed for some subtypes of vascular cognitive impairment, and there is a pressing need to validate and further refine these. Clinical trials in vascular cognitive impairment are in their infancy but support the value of therapeutic interventions for symptomatic treatment.

Cerebrovascular Disorders↗

Staging: relevance for trial design in vascular burden of the brain.

Cerebrovascular small vessel disease is now believed to be the major source of vascular burden of the brain. Cerebrovascular small vessel disease and Alzheimer's disease appear to represent pathophysiologic and clinical continua, rather than dichotomous entities. It appears that common etiopathologic mechanisms underlie the clinical presentation of both of these conditions. Therefore, the staging procedures that have been developed for the clinical continuum of age-associated memory impairment, mild cognitive impairment, and the progressive dementia of Alzheimer's disease appear to be applicable for the same continua in cerebrovascular small vessel disease. Although temporal and prognostic aspects have been studied for the Alzheimer's-related portions of this clinical staging continuum, they remain to be elucidated for cerebrovascular small vessel disease.

Aged↗

Shift from fibrillar to nonfibrillar Abeta deposits in the neocortex of subjects with Alzheimer disease.

A morphometric study of amyloid-beta-positive plaques in the neocortex of eight non-demented people from 68 to 82 years of age and 17 subjects with late-stage Alzheimer disease (GDS stage 7/FAST stages 7a-f) from 73 to 93 years of age shows a shift from prevalence of fibrillar plaques to prevalence of nonfibrillar plaques. In the aged, non-demented subjects, about 4/mm^2 plaques are detectable in the neocortex, and the majority are fibrillar plaques. Specifically, 64% found to be classical fibrillar and Thioflavin-S-positive bright primitive plaques. A lower percentage of pale primitive plaques (35%) relatively small proportion of plaques that are poor in thioflavin S-positive fibrils. The numerical density of plaques in the severe stage of AD increases to about 41/mm^2. Severely demented subjects appear to maintain an active process of fibrillar plaque formation. This is reflected in the presence of 3% bright primitive plaques. Severely demented subjects also manifest plaque degradation, reflected in the presence of 22% and 48% percentages of classical fibrillar plaques in non-demented subjects and in the end stage of disease suggest that once activated, the process of fibrillar plaque formation persists at a somewhat stable rate during the whole course of brain amyloidosis.

Journal Article↗

ADCS Prevention Instrument Project: ADCS-clinicians' global impression of change scales (ADCS-CGIC), self-rated and study partner-rated versions.

BACKGROUND: Because primary prevention trials will require large samples and modest treatment effects are expected, the use of standard clinician-administered, clinic-based measures are unlikely to be feasible. There is a need for proxy-administered outcome measures. The goal of the Alzheimer's Disease Cooperative Study (ADCS) Prevention Instrument Project was to conduct a simulated Alzheimer disease prevention trial in 650 nondemented elderly (Ferris et al, 2006). This involved comparison of data acquisition from both home and clinic and the use of both informant-ratings and self-ratings. Important outcomes included clinical global impressions of change (CGIC) as indicators of clinically meaningful change. Such ratings provide verification that the effects of a medication as measured on rating scales are readily observable and clinically meaningful. One objective was to develop self-rated and study partner-rated CGICs optimized for nondemented elderly or people with very early Alzheimer disease. An important consideration was whether global assessments are specific and sensitive measures of change during a prevention trial. METHODS: A self-administered CGIC and a study partner-rated CGIC were developed to be used either in the clinic or at home. Using 3-month follow-up data, we determined its reliability and validity with 317 subject-partner pairs. We compared subject-ratings with partner-ratings, clinic-based with home-based ratings, and ratings based on severity as determined by the Clinical Dementia Rating scale. RESULTS: There were no differences between clinic and home ratings. Overall, 24% of subjects rated themselves, and 10% of study partners rated the subjects, as minimally to markedly improved. Subjects and partners agreed to within 1 point of their ratings 83% of the time on the 7-point scale. There were weak correlations, generally <0.20, with change scores of selected clinical rating scales. DISCUSSION: The CGICs behaved as expected, showing no overall change over 3 months, no difference between administrations at home compared with clinics, and concurrent validity. Some subjects tended to rate themselves better than their partners rated them. These analyses show the potential for using home-based CGICs which can be completed with minimal supervision and allow assessments of potential preventative interventions.

Activities of Daily Living↗

Evidence and mechanisms of retrogenesis in Alzheimer's and other dementias: management and treatment import.

Retrogenesis is the process by which degenerative mechanisms reverse the order of acquisition in normal development. Alzheimer's disease (AD) and related conditions in the senium have long been noted to resemble "a return to childhood" Previously, we noted that the functional stages of AD precisely and remarkably recapitulated the acquisition of the same functional landmarks in normal human development. Subsequent work indicated that this developmental recapitulation also applied to the cognitive and related symptoms in AD. Remarkably, further investigations revealed that the same neurologic "infantile" reflexes, which mark the emergence from infancy in normal development, are equally robust indicators of corresponding stages in AD. Neuropathologic and biomolecular mechanisms for these retrogenic processes are now evident. For example, the pattern of myelin loss in AD appears to mirror the pattern of myelin acquisition in normal development. Also, recent findings indicate that mitogenic factors become reactivated in AD, and, consequently, the most actively "growing" brain regions are the most vulnerable. Because of this robust retrogenic process, the stages of AD can be translated into corresponding developmental ages (DAs). These DAs can account for the overall management and care needs of AD patients. A science of AD management can be formulated on the basis of the DA of the Alzheimer's patient, taking into consideration differences of AD from normal development as well as homologies.

Adolescent↗