Psychometric Cognitive Decline Precedes the Advent of Subjective Cognitive Decline in the Evolution of Alzheimer's Disease

BACKGROUND

We have described the clinical stages of the brain aging and Alzheimer's disease (AD) continuum. In terms of the pre-dementia stages of AD, we introduced the terminology "mild cognitive impairment" (MCI) for the first pre-dementia stage and "subjective cognitive decline" (SCD) for the pre-MCI stage. We now report the characteristics of a pre-SCD condition eventuating in likely AD.

OBJECTIVE

The aim of this study was to characterize a pre-SCD condition eventuating in AD.

METHOD

Sixty healthy persons with "no cognitive decline" (NCD) were recruited and 47 were followed (mean baseline age, 64.1 ± 8.9 years; mean follow-up time, 6.7 ± 3.1 years). Outcome was determined at the final assessment prior to 2002 as "decliner," if SCD or worse, or "nondecliner" if NCD.

RESULTS

After controlling for age, gender, years of education, and follow-up time, there was a between-group difference in the decline rate (p < 0.001). Also, after controlling for demographic variables and follow-up time, the combinatorial psychometric score was lower at baseline in the future decliners (p = 0.035). Of the 9 psychometric variables, after controlling for demographic variables and follow-up time, 3 were significantly lower at baseline in future decliners. Since AD is known to be age related and all subjects in this study were otherwise healthy, we also did an analysis without controlling for age. The combinatorial psychometric score was highly significantly better at baseline in the future nondecliners than in the future decliners (p = 0.008).

CONCLUSION

This is ostensibly the first study to link psychometric cognitive decline to the subsequent SCD stage of eventual AD.

Two Year Outcomes, Cognitive and Behavioral Markers of Decline in Healthy, Cognitively Normal Older Persons with Global Deterioration Scale Stage 2 (Subjective Cognitive Decline with Impairment)

BACKGROUND

Little is known with respect to behavioral markers of subjective cognitive decline (SCD), a condition initially described in association with Global Deterioration Scale (GDS) stage 2.

OBJECTIVE

Two-year interval behavioral markers were investigated herein.

METHODS

Subjects from a published 7-year outcome study of GDS stage 2 subjects were selected. This study had demonstrated a hazard ratio of 4.5 for progression of GDS stage 2, in comparison with GDS stage 1 (no subjective or objective cognitive decline) subjects, after controlling for demographic and temporal variables. Because GDS 2 subjects have previously demonstrated impairment in comparison with healthy persons free of complaints, we herein suggest the terminology "SCD(I)" for these persons. 98 SCD(I) persons, 63 women and 35 men, mean baseline age, 67.12±8.75 years, with a mean educational background of 15.55±2.60 years, and mean baseline MMSE scores of 28.9±1.24 were followed for 2.13±0.30 years.

RESULTS

Observed annual decline on the GDS was 6.701% per annum, very close to a 1986 published estimate. At follow up, the MMSE, and 7 of 8 psychometric tests did not decline significantly. Of 21 Hamilton Depression Scale items, 2 improved and the remainder were unchanged. Anxieties declined from multiple perspectives. The Brief Cognitive Rating Scale (BCRS) declined significantly (p < 0.001), with component declines in Remote memory (p < 0.01), and Functioning/self-care (p = 0.01).

CONCLUSION

SCD(I) persons decline at an annual rate of approximately 6.7% /year from several recent studies. The BCRS assessments and the Digit Symbol Substitution Test can be sensitive measures for future studies of progression mitigation.

Comprehensive, Individualized, Person-Centered Management of Community-Residing Persons with Moderate-to-Severe Alzheimer Disease: A Randomized Controlled Trial

BACKGROUND/AIMS

The aim was to examine added benefits of a Comprehensive, Individualized, Person-Centered Management (CI-PCM) program to memantine treatment.

METHODS

This was a 28-week, clinician-blinded, randomized, controlled, parallel-group study, with a similar study population, similar eligibility criteria, and a similar design to the memantine pivotal trial of Reisberg et al. [N Engl J Med 2003;348:1333-1341]. Twenty eligible community-residing Alzheimer disease (AD) subject-caregiver dyads were randomized to the CI-PCM program (n = 10) or to usual community care (n = 10). Primary outcomes were the New York University Clinician's Interview-Based Impression of Change Plus Caregiver Input (NYU-CIBIC-Plus), assessed by one clinician set, and an activities of daily living inventory, assessed by a separate clinician set at baseline and at weeks 4, 12, and 28.

RESULTS

Primary outcomes showed significant benefits of the CI-PCM program at all post-baseline evaluations. Improvement on the NYU-CIBIC-Plus in the management group at 28 weeks was 2.9 points over the comparator group. The memantine 2003 trial showed an improvement of 0.3 points on this global measure in memantine-treated versus placebo-randomized subjects at 28 weeks. Hence, globally, the management program intervention benefits were 967% greater than memantine treatment alone.

CONCLUSION

These results are approximately 10 times those usually observed with both nonpharmacological and pharmacological treatments and indicate substantial benefits with the management program for advanced AD persons.

The BEHAVE-AD assessment system: a perspective, a commentary on new findings, and a historical review

BACKGROUND

Behavioral and psychological symptoms of dementia (BPSD) and associated disturbances in Alzheimer's disease (AD) are a source of distress and burden for spouses, professional caregivers, and others with responsibilities for the care of individuals with AD. BPSD with behavioral disturbances are also associated with more rapid institutionalization and increased morbidity and mortality for persons with AD.

OBJECTIVES

In this review and commentary, we discuss the history of the development of BPSD and behavioral disturbance assessments, which are distinct from those evaluating cognitive and functional symptoms of AD. In particular, we review the informant-based Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD), the related, potentially more sensitive, BEHAVE-AD Frequency-Weighted Severity Scale (BEHAVE-AD-FW), and the direct subject evaluation-based Empirical BEHAVE-AD Rating Scale (E-BEHAVE-AD). The kinds of medications that alleviate behavioral symptoms on these measures as well as the problems and possibilities for further advances with these medications are discussed. Finally, the importance of distinguishing BPSD and behavioral disturbance remediation in AD from the treatment of cognitive decline and other aspects of AD is emphasized in the context of appropriate assessment methodology. The objective of this paper is to provide a framework for further advances in the treatment of BPSD and associated behavioral disturbances in AD and, consequently, a framework for continuing improvements in the lives of individuals with AD and those who share the burden of the disease with the AD person.

Outcome over seven years of healthy adults with and without subjective cognitive impairment

BACKGROUND

Subjective cognitive impairment (SCI) in older persons without manifest symptomatology is a common condition with a largely unclear prognosis. We hypothesized that (1) examining outcome for a sufficient period by using conversion to mild cognitive impairment (MCI) or dementia would clarify SCI prognosis, and (2) with the aforementioned procedures, the prognosis of SCI subjects would differ significantly from that of demographically matched healthy subjects, free of SCI, termed no cognitive impairment (NCI) subjects.

METHODS

A consecutive series of healthy subjects, aged > or =40 years, presenting with NCI or SCI to a brain aging and dementia research center during a 14-year interval, were studied and followed up during an 18-year observation window. The study population (60 NCI, 200 SCI, 60% female) had a mean age of 67.2 +/- 9.1 years, was well-educated (mean, 15.5 +/- 2.7 years), and cognitively normal (Mini-Mental State Examination, 29.1 +/- 1.2).

RESULTS

A total of 213 subjects (81.9% of the study population) were followed up. Follow-up occurred during a mean period of 6.8 +/- 3.4 years, and subjects had a mean of 2.9 +/- 1.6 follow-up visits. Seven NCI (14.9%) and 90 SCI (54.2%) subjects declined (P < .0001). Of NCI decliners, five declined to MCI and two to probable Alzheimer's disease. Of SCI decliners, 71 declined to MCI and 19 to dementia diagnoses. Controlling for baseline demographic variables and follow-up time, Weibull proportional hazards model revealed increased decline in SCI subjects (hazard ratio, 4.5; 95% confidence interval, 1.9-10.3), whereas the accelerated failure time model analysis with an underlying Weibull survival function showed that SCI subjects declined more rapidly, at 60% of the rate of NCI subjects (95% confidence interval, 0.45-0.80). Furthermore, mean time to decline was 3.5 years longer for NCI than for SCI subjects (P = .0003).

CONCLUSIONS

These results indicate that SCI in subjects with normal cognition is a harbinger of further decline in most subjects during a 7-year mean follow-up interval. Relevance for community populations should be investigated, and prevention studies in this at-risk population should be explored.

Prediction of longitudinal cognitive decline in normal elderly with subjective complaints using electrophysiological imaging

An extensive literature reports changes in quantitative electroencephalogram (QEEG) with aging and a relationship between magnitude of changes and degree of clinical deterioration in progressive dementia. Longitudinal studies have demonstrated QEEG differences between mild cognitively impaired (MCI) elderly who go on to decline and those who do not. This study focuses on normal elderly with subjective cognitive complaints to assess the utility of QEEG in predicting future decline within 7 years. Forty-four normal elderly received extensive clinical, neurocognitive and QEEG examinations at baseline. All study subjects (N = 44) had only subjective complaints but no objective evidence of cognitive deficit (evaluated using the Global Deterioration Scale [GDS] score, GDS stage = 2) at baseline and were re-evaluated during 7-9 year follow-up. Baseline QEEGs of Decliners differed significantly (p < 0.0001, by MANOVA) from Non-Decliners, characterized by increases in theta power, slowing of mean frequency, and changes in covariance among regions, especially on the right hemisphere. Using logistic regression, an R2 of 0.93 (p < 0.001) was obtained between baseline QEEG features and probability of future decline, with an overall predictive accuracy of 90%. These data indicate high sensitivity and specificity for baseline QEEG as a differential predictor of future cognitive state in normal, subjectively impaired elderly.

Addition of a frequency-weighted score to the Behavioral Pathology in Alzheimer's Disease Rating Scale: the BEHAVE-AD-FW: methodology and reliability

The Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD) is a well-established instrument, designed to assess potentially remediable behavioral symptoms in Alzheimer's disease (AD) patients as well as to evaluate treatment outcome. It consists of 25 symptoms grouped into seven categories. Each symptom is scored on the basis of severity on a four-point scale. A knowledgeable caregiver is queried and items are scored on the basis of symptoms noted in the preceding two weeks. Reliability, construct validity and criterion validity data for the BEHAVE-AD have previously been published. Because of the significance of psychopathology in dementia, it is necessary to optimally describe and define the nature, magnitude and prevalence of behavioral symptomatology. Accordingly, a frequency component was added to each of the 25 items of the BEHAVE-AD scale. The objective of the present report is to describe this new Behavioral Pathology in Alzheimer's Disease Frequency-Weighted Severity Scale (BEHAVE-AD-FW) and to establish its inter-rater reliability. In this investigation the BEHAVE-AD-FW scale was administered to caregivers of 28 patients with either mildly impaired cognitive function or a dementia diagnosis. Two clinicians separately and independently rated the responses. Analyses determined that the intraclass correlation coefficients (ICCs) for the frequency component varied between 0.86 and 0.97 for each of the seven BEHAVE-AD categories (p(s) < 0.001). ICCs for the frequency-weighted scores (item severity score x item frequency score) ranged from 0.69 to 0.98 for the seven symptom categories (p(s) < 0.001). For the BEHAVE-AD-FW total scores, the ICC was 0.91 (P < 0.001). These results indicate that the frequency-weighted component is a reliable addition to the BEHAVE-AD scale.

Reliability of routine clinical instruments for the assessment of Alzheimer's disease administered by telephone

We investigated the reliability, using a telephone interview procedure, of cognitive, functional, and behavioral scales in an elderly population with normal aging and dementia. Two clinicians performed the assessments: one performed the assessments in a telephone interview format and the other conducted the assessments at the clinic. The telephone interview always preceded the clinic evaluation (2-30 days apart), and both clinicians were blind to any previous evaluations of the patient. The intraclass correlation coefficients between the telephone interview and the ratings obtained by a different clinician on the clinic evaluation varied between 0.92 and 0.98 (P's < or = .001) for comprehensive test scores. These results indicate that a telephone interview format, although not a substitute for a face-to-face diagnostic evaluation, is a reliable procedure for obtaining the assessment modalities studied. These findings are particularly important in aged and dementia research populations where personal contact may not always be feasible.

Mortality and temporal course of probable Alzheimer's disease: a 5-year prospective study

Alzheimer's disease (AD) is associated with an increased mortality in comparison with aged control populations. The relationship between the clinical and the temporal course of AD has not been well studied over significant intervals. Community-residing patients with probable AD (N = 103, 42 men, mean age = 70.2 +/- 8.0 years) were studied at baseline on demographic and clinical variables, including measures of global deterioration (Global Deterioration Scale; GDS), mental status and cognition (e.g., Mini-Mental State Examination; MMSE), and functional impairment (Functional Assessment Staging; FAST). Baseline characteristics included a GDS range of Stage 4, 5, or 6 (38.8%, 39.8%, and 21.4%, respectively) and a mean MMSE score of 15.4 +/- 5.6. The mean follow-up interval was 4.6 +/- 1.4 years. Follow-ups were done blind to baseline measures and when necessary were conducted in residential and nursing home settings. Of locatable subjects (n = 95, 92%), 30 (31.6%) were decreased. Survivors (n = 65) had a mean GDS stage of 6.2 +/- 0.9 and a mean MMSE score of 5.1 +/- 6.9; 51% had MMSE scores of 0. Increased age and male gender, but not baseline clinical dementia variables, increased the risk of death (ps < .01). Change in clinical variables correlated significantly with time elapsed (r = .32, p < .05, for MMSE change, to r = .48, p < .001, for GDS change). Significant variance in temporal change (i.e., time elapsed) was accounted for by change in two of the five clinical measures studied (i.e., GDS and FAST; multiple r = .53). The results support previous estimates of mean duration of the GDS and FAST stages. For subjects with probable AD followed over approximately 5 years, clinical variables changed significantly over time in survivors. However, the majority of temporal variance in the course of AD remains unexplained.

Overview of methodologic issues for pharmacologic trials in mild, moderate, and severe Alzheimer's disease

To address the issue of mild, moderate, and severe Alzheimer's disease (AD), it is necessary to initially establish some agreement on terminology. In recent decades, these terms have frequently been defined using screening instrument scores with measures such as the Mini-Mental State Examination (MMSE). There are many problems with this approach, perhaps the most salient of which is that it has contributed to the total and tragic neglect of patients with severe AD. An alternative approach to the classification of AD severity is staging. This approach has advanced to the point where moderately severe and severe AD can be described in detail. Procedures for describing this previously neglected latter portion of AD have recently been extensively validated. Staging is also uniquely useful at the other end of the severity spectrum, in differentiating early aging brain/behavior changes, incipient AD, and mild AD. Temporally, with staging procedures, it is possible to track the course of AD approximately three times more accurately than with the MMSE. The net result of the advances in AD delineation is that issues such as prophylaxis, modification of course, treatment of behavioral disturbances, loss of ambulation, progressive rigidity, and the development of contractures in AD patients can now be addressed in a scientifically meaningful way that will hopefully bestow much benefit in AD patients and those who care for them.

Pharmacologic treatment of Alzheimer's disease: a methodologic critique based upon current knowledge of symptomatology and relevance for drug trials

Research on the nature of clinical symptomatology in AD indicates that two fundamentally different types of symptoms are identifiable. Symptoms within each of these two domains have common characteristics. The first symptomatic domain has been termed the "cognitive domain" and the second the "noncognitive behavioral domain." Symptoms and losses in the cognitive domain occur invariably and progressively with the advance of AD over time. Symptoms in the behavioral domain do not invariably occur in AD and do not progress monotonically with the advance in AD over time. However, characteristic behavioral domain symptoms can be described over the course of AD. The two symptomatic domains are likely to differ not only in nature and progression in AD, but also in underlying pathophysiology and in terms of possible treatment modalities. They also pose fundamentally different issues of assessment in AD. These distinct factors necessitate the separate assessment of the two symptomatic domains in AD treatment trials. Judgments of efficacy and utility in remediating either symptomatic domain in AD should take into consideration the effects of treatment on both cognitive domain and behavioral domain symptoms separately and interactively. Appropriate assessment procedures are discussed.