Identifying dementia in Down syndrome with the Severe Impairment Battery, Brief Praxis Test and Dementia Scale for People with Learning Disabilities.

BACKGROUND: Individuals with Down syndrome (DS) are at high risk for dementia, specifically Alzheimer's disease. However, many measures regularly used for the detection of dementia in the general population are not suitable for individuals with DS due in part to floor effects. Some measures, including the Severe Impairment Battery (SIB), Brief Praxis Test (BPT) and Dementia Scale for People with Learning Disabilities (DLD), have been used in clinical trials and other research with this population. Validity research is limited, particularly regarding the use of such tools for detection of prodromal dementia in the DS population. The current project presents baseline cross-sectional SIB, BPT and DLD performance in order to characterise their predictive utility in discriminating normal cognition, possible dementia and probable dementia in adult DS. METHOD: Baseline SIB, BPT and DLD performances from 100 individuals (no dementia = 68, possible dementia = 16 & probable dementia = 16) were examined from a longitudinal cohort of aging individuals with DS. Receiver operating characteristic curves investigated the accuracy of these measures in relation to consensus dementia diagnoses, diagnoses which demonstrated high percent agreement with the examining neurologist's independent diagnostic impression. RESULTS: The SIB and BPT exhibited fair discrimination ability for differentiating no/possible versus probable dementia [area under the curve (AUC) = 0.61 and 0.66, respectively]. The DLD exhibited good discrimination ability for differentiating no versus possible/probable dementia (AUC = 0.75) and further demonstrated better performance of the DLD Cognitive subscale compared with the DLD Social subscale (AUC = 0.77 and 0.67, respectively). CONCLUSIONS: Results suggest that the SIB, BPT and DLD are able to reasonably discriminate consensus dementia diagnoses in individuals with DS, supporting their continued use in the clinical assessment of dementia in DS. The general performance of these measures suggests that further work in the area of test development is needed to improve on the AUCs for dementia status discrimination in this unique population. At present, however, the current findings suggest that the DLD may be the best option for reliable identification of prodromal dementia in this population, reinforcing the importance of including informant behaviour ratings in assessment of cognition for adults with DS.

Evaluation of an 8-item Severe Impairment Battery (SIB-8) vs. the full SIB in moderate to severe Alzheimer's disease patients participating in a donepezil study.

AIM: The Severe Impairment Battery (SIB), a reliable cognitive measure for evaluating treatment response in advanced Alzheimer's disease (AD), takes approximately 20 min to administer. A recently derived 8-item version of the SIB - the SIB-8 - which takes about 3 min to administer, may represent a more convenient tool for use in clinical practice. The current analyses further explored the SIB-8 scale with respect to its validity and sensitivity. METHODS: A post hoc analysis was performed using data from a 24-week trial of donepezil 23 mg/day and 10 mg/day in > 1400 patients with moderate to severe AD [baseline Mini-Mental State Examination (MMSE) score 0-20]. Treatment effects on cognition (patterns of score change) were assessed using the full SIB and SIB-8 in the total study population and subgroups based on concomitant memantine use and baseline MMSE. Internal consistency/agreement and correlations between the SIB and SIB-8 and other clinical end points were evaluated. RESULTS: Assessment of score changes from baseline to week 24 with donepezil (23 or 10 mg/day) demonstrated comparable patterns of change when using the SIB-8 and the full SIB, despite inherent differences in the total score ranges for the two scales. Internal consistency/agreement between the full SIB and SIB-8 was good (Cronbach's alphas: 0.77-0.95). SIB-8 scores reliably correlated with SIB total scores (r = 0.859, baseline; r = 0.900, week 24; p < 0.0001), as well as MMSE scores (r = 0.7163, baseline; r = 0.7963, week 24; p < 0.0001). Scores on both SIB scales were moderately associated with functional measures at baseline and week 24. CONCLUSIONS: In this post hoc analysis, similar treatment effects were measured by the full SIB and the SIB-8. Very good internal consistency/agreement and strong correlations between the SIB and the more rapid and convenient SIB-8 indicate that the SIB-8 may be a useful and efficient clinical proxy for the full SIB in evaluating treatment response in patients with advanced AD.

Differential reports of pain and depression differentiate mild cognitive impairment from cognitively intact elderly participants.

BACKGROUND: Positive associations between pain and depression in the general population have been well characterized; however, the interplay between pain, depression, and early cognitive decline, characterized as mild cognitive impairment (MCI), is poorly understood. METHODS: The current study examined the association of self-reported pain complaints (measured by the 36-item Short Form Health Survey) and self-reported depressive symptoms (measured by the 30-item Geriatric Depression Scale) in cognitively intact participants (n = 492) and participants with a clinical diagnosis of MCI (n = 83). RESULTS: Depressive symptoms and subjective reports of pain were significantly associated in the entire sample (r = .29; P < .0001). Multiple logistic regression modeling (adjusted for age, education, and APOE4 status as covariates) demonstrated that while depressive symptoms were positively associated with the diagnosis of MCI (P < .001), subjective pain reports were negatively associated with MCI (P < .002). CONCLUSION: While the negative association of subjective pain complaints with MCI might arguably be explained by the development of anosognosia, self-reports of depressive symptoms were actually increased in these participants, suggesting preserved insight into cognitive decline-associated symptoms. It is possible that preferential involvement of limbic circuitry in MCI could explain these findings. Future studies are needed to elucidate the reasons for the dissociation of pain and depressive symptoms in MCI described in the present article.

Intervention for Cognitive Reserve Enhancement in Delaying the Onset of Alzheimer's Symptomatic Expression (INCREASE) Study: Results from a Randomized Controlled Study of Medication Therapy Management Targeting a Delay in Prodromal Dementia Symptom Progression.

BACKGROUND: Cognitive reserve has been hypothesized as a mechanism to explain differences in individual risk for symptomatic expression of Alzheimer's Disease (AD). Inappropriate medications may diminish cognitive reserve, precipitating the transition from preclinical AD (pAD) to a symptomatic state. To date, there is limited data on the potential impact of medication optimization as a potential tool for slowing the symptomatic expression of AD. OBJECTIVES: (1) To test the efficacy of a medication therapy management intervention designed to bolster cognitive reserve in community-dwelling older adults without dementia. (2) To evaluate the efficacy of intervention by baseline pAD status. DESIGN: A 1-year randomized controlled trial was conducted in community-dwelling older adults without dementia. Randomization was stratified by amyloid ß positron emission tomography levels. SETTING: Community-based, Lexington, Kentucky. PARTICIPANTS: Adults 65 years or older with no evidence of dementia and reporting at least one potentially inappropriate medication as listed in the Beers 2015 criteria were recruited. The study aimed to enroll 90 participants based on the a priori sample size calculation. INTERVENTION: Medication therapy management versus standard of care. MEASUREMENTS: Primary outcomes were: (1) one-year changes in the Medication Appropriateness Index; (2) one-year changes in Trail Making Test B under scopolamine challenge. RESULTS: The medication therapy management intervention resulted in significant improvement in Medication Appropriateness Index scores. Overall, there was no beneficial effect of the medication therapy management on Trail Making Test B scores, however stratified analysis demonstrated improvement in Trail Making Test B challenged scores associated with the medication therapy management for those with elevated amyloid ß positron emission tomography levels consistent with pAD. CONCLUSIONS: Medication therapy management can reduce inappropriate medication use in older adults at risk for AD. Our study indicated beneficial cognitive effects in those with preclinical Alzheimer's Disease. No statistically significant effects were evident in the study group as a whole, or in those without preclinical cerebral amyloidosis. Further work designed to improve the effectiveness of the medication therapy management approach and defining other preclinical pathologic states that may benefit from medication optimization are readily achievable goals for promoting improved cognitive health and potentially delaying the onset of symptomatic AD.

Mental Component Score (MCS) from Health-Related Quality of Life Predicts Incidence of Dementia in U.S. Males.

BACKGROUND: The Medical Outcomes Study Questionnaire Short Form 36 health survey (SF-36) measures health-related quality of life (HRQoL) from the individual's point of view and is an indicator of overall health status. OBJECTIVE: To examine whether HRQoL shows differential changes over time prior to dementia onset and investigate whether HRQoL predicts incidence of dementia. DESIGN: Prevention of Alzheimer's Disease (AD) by Vitamin E and Selenium (PREADViSE) trial, which recruited 7,547 non-demented men between 2002 and 2009. A subset of 2,746 PREADViSE participants who completed up to five SF-36 assessments at annual visits was included in the current analysis. SETTING: Secondary data analysis of PREADViSE data. PARTICIPANTS: A subset of 2,746 PREADViSE participants who completed up to five SF-36 assessments at annual visits was included in the current analysis. MEASUREMENTS: Two summary T scores were generated for analysis: physical component score (PCS) and mental component score (MCS), each with a mean of 50 (standard deviation of 10); higher scores are better. Linear mixed models (LMM) were applied to determine if mean component scores varied over time or by eventual dementia status. Cox proportional hazards regression was used to determine if the baseline component scores were associated with dementia incidence, adjusting for baseline age, race, APOE-4 carrier status, sleep apnea, and self-reported memory complaint at baseline. RESULTS: The mean baseline MCS score for participants who later developed dementia (mean± SD: 53.9±9.5) was significantly lower than for those participants who did not develop dementia during the study (mean±SD: 56.4±6.5; p = 0.005). Mean PCS scores at baseline (dementia: 49.3±7.9 vs. non-dementia: 49.8±7.8) were not significantly different (p = 0.5) but LMM analysis showed a significant time effect. For MCS, the indicator for eventual dementia diagnosis was significantly associated with poorer scores after adjusting for baseline age, race, and memory complaint. Adjusted for other baseline risk factors, the Cox model showed that a 10-unit increase in MCS was associated with a 44% decrease in the hazard of a future dementia diagnosis (95% CI: 32%-55%). CONCLUSION: The SF-36 MCS summary score may serve as a predictor for future dementia and could be prognostic in longitudinal dementia research.

Clinical features of mild cognitive impairment differ in the research and tertiary clinic settings.

OBJECTIVE: Comparative analysis of subjects with mild cognitive impairment (MCI) diagnosed in a primary research setting and those seen in a tertiary care memory disorders clinic. METHODS: Subjects who received a diagnosis of MCI between July 1, 2005, and December 31, 2006, in a longitudinal research study of normal cognition (n = 48) and patients diagnosed in a tertiary care referral clinic (n = 34) were evaluated using similar methodologies. Comparative analyses of detailed medical, neurological and neuropsychological data are presented. RESULTS: The diagnosis of MCI was not accepted by 13 of 48 subjects (27%) classified as MCI in the primary research setting. Nondegenerative, potentially treatable causes of cognitive decline were found in 3 of 34 subjects (9%) seen in the tertiary referral clinic and in 11 of 35 subjects (31%) identified as MCI in the primary research setting (p = 0.02, Fisher's exact test). MCI subjects identified in the primary research setting were older than those referred to the memory clinic (mean +/- SD, 79.7 +/- 7.0 vs. 71.5 +/- 9.0 years, p < 0.0001, t test) and had more years of education (16.0 +/- 3.2 vs. 13.6 +/- 4.2 years, p < 0.01, t test). MCI subjects in the primary research setting appeared to be in a milder stage of disease, characterized by higher Mini-Mental State Examination scores (28.2 +/- 1.8 vs. 25.7 +/- 1.8, p < 0.0001), and a tendency towards single domain involvement, predominantly memory (mean number of domains involved, 1.0 vs. 2.5, p < 0.0001). More advanced stages of MCI, seen in the tertiary referral population, had additional involvement of attention (p < 0.0001, Fisher's exact test) and visuospatial domains (p < 0.0002, Fisher's exact test). Semiquantitative grading of hippocampal and medial temporal lobe atrophy did not differ between groups (p = 0.81, Mann-Whitney U test). CONCLUSIONS: The diagnosis of MCI may be unwelcome in naïve persons. Remedial causes of MCI should be actively investigated. Demographic and clinical characteristics of MCI differ between research subjects and patients referred to a tertiary care clinic.

Diabetes mitigates the role of memory complaint in predicting dementia risk: Results from the Prevention of Alzheimer's Disease with Vitamin E and Selenium Study.

BACKGROUND: Subjective memory complaints (SMCs) are associated with increased risk of dementia in older adults, but the role of comorbidities in modifying this risk is unknown. OBJECTIVES: To assess whether comorbidities modify estimated dementia risk based on SMCs. DESIGN: The Prevention of Alzheimer's Disease with Vitamin E and Selenium Study (PREADVISE) was designed as an ancillary study to the Selenium and Vitamin E Cancer Prevention Trial (SELECT), a randomized, multi-center prostate cancer prevention trial with sites in the Unites States, Puerto Rico, and Canada. In 2009, PREADVISE and SELECT were changed into cohort studies. SETTING: Secondary analysis of PREADVISE data. PARTICIPANTS: PREADVISE recruited 7,540 non-demented male volunteers from participating SELECT sites from 2002 to 2009. SMCs, demographics, and comorbidities including hypertension, diabetes, coronary artery bypass graft (CABG), stroke, sleep apnea, and head injury were ascertained by participant interview. MEASUREMENTS: Cox models were used to investigate whether baseline comorbidities modified hazard ratios (HR) for SMC-associated dementia risk using two methods: (1) we included one interaction term between SMC and a comorbidity in the model at a time, and (2) we included all two-way interactions between SMC and covariates of interest and reduced the model by "backward" selection. SMC was operationalized as any complaint vs. no complaint. RESULTS: Baseline SMCs were common (23.6%). In the first analyses, with the exception of stroke, presence of self-reported comorbidities was associated with lower estimated HR for dementia based on SMC status (complaint vs. no complaint), but this difference was only significant for diabetes. In the second analysis, the two-way interactions between SMC and race as well as SMC and diabetes were significant. Here, black men without diabetes who reported SMC had the highest estimated dementia risk (HR=5.05, 95% CI 2.55-10.00), while non-black men with diabetes who reported SMC had the lowest estimated risk (HR=0.71, 95% CI 0.35-1.41). CONCLUSIONS: SMCs were more common among men with comorbidities, but these complaints appeared to be less predictive of dementia risk than those originating from men without comorbidities, suggesting that medical conditions such as diabetes may explain SMCs that are unrelated to an underlying neurodegenerative process.

Factors Associated with Unmet Needs among African-American Dementia Care Providers.

Racial and ethnic minorities currently comprise 20% of the U.S. population; in 2050, this figure is expected to rise to 42%. As a result, Alzheimer's disease (AD), the 5th leading cause of death for people aged 65 and older, is likely to increase in these groups. Most dementia caregiving for these populations comes from family and friends, especially among families with lower socioeconomic status. A convenience sample of 30 African-American dementia caregivers was interviewed to determine unmet needs. Participants expressed a limited desire for formal services, such as support groups, legal advice, case management, and homemaker services. Instead, commonly expressed needs were daytime respite care and especially a desire for family and social support. Many caregivers expressed a need for other family members to share responsibility in the process; therefore, methods for caregiver support that address multiple family members in care provision may be beneficial for this group.

(1)H-MRS metabolites in adults with Down syndrome: Effects of dementia.

To determine if proton magnetic resonance spectroscopy ((1)H-MRS) detect differences in dementia status in adults with Down syndrome (DS), we used (1)H-MRS to measure neuronal and glial metabolites in the posterior cingulate cortex in 22 adults with DS and in 15 age- and gender-matched healthy controls. We evaluated associations between (1)H-MRS results and cognition among DS participants. Neuronal biomarkers, including N-acetylaspartate (NAA) and glutamate-glutamine complex (Glx), were significantly lower in DS patients with Alzheimer's should probably be changed to Alzheimer (without ' or s) through ms as per the new naming standard disease (DSAD) when compared to non-demented DS (DS) and healthy controls (CTL). Neuronal biomarkers therefore appear to reflect dementia status in DS. In contrast, all DS participants had significantly higher myo-inositol (MI), a putative glial biomarker, compared to CTL. Our data indicate that there may be an overall higher glial inflammatory component in DS compared to CTL prior to and possibly independent of developing dementia. When computing the NAA to MI ratio, we found that presence or absence of dementia could be distinguished in DS. NAA, Glx, and NAA/MI in all DS participants were correlated with scores from the Brief Praxis Test and the Severe Impairment Battery. (1)H-MRS may be a useful diagnostic tool in future longitudinal studies to measure AD progression in persons with DS. In particular, NAA and the NAA/MI ratio is sensitive to the functional status of adults with DS, including prior to dementia.

Self-Reported Memory Complaints: A Comparison of Demented and Unimpaired Outcomes.

BACKGROUND: Subjective memory complaints are common in aged persons, indicating an increased, but incompletely understood, risk for dementia. OBJECTIVE: To compare cognitive trajectories and autopsy results of individuals with subjective complaints after stratifying by whether a subsequent clinical dementia occurred. DESIGN: Observational study. SETTING: University of Kentucky cohort with yearly longitudinal assessments and eventual autopsies. PARTICIPANTS: Among 516 patients who were cognitively intact and depression-free at enrollment, 296 declared a memory complaint during follow-up. Among those who came to autopsy, 118 died but never developed dementia, while 36 died following dementia diagnosis. MEASUREMENTS: Cognitive domain trajectories were compared using linear mixed models adjusted for age, gender, years of education and APOE status. Neuropathological findings were compared cross-sectionally after adjustment for age at death. RESULTS: While the groups had comparable cognitive test scores at enrollment and the time of the first declaration of a complaint, the group with subsequent dementia development had steeper slopes of decline in episodic memory and naming but not fluency or sequencing. Autopsies showed the dementia group had more severe Alzheimer pathology and a higher proportion of subjects with hippocampal sclerosis of aging and arteriolosclerosis, whereas the non-demented group had a higher proportion expressing primary age related tauopathy (PART). CONCLUSIONS: While memory complaints are common among the elderly, not all individuals progress to dementia. This study indicates that biomarkers are needed to predict whether a complaint will lead to dementia if this is used as enrollment criteria in future clinical trials.

The Effect of Vascular Neuropathology on Late-life Cognition: Results from the SMART Project.

BACKGROUND: Cerebral vascular pathology may contribute to cognitive decline experienced by some elderly near death. Given evidence for mixed neuropathologies in advanced age, preventing or reducing cerebrovascular burden in late life may be beneficial. OBJECTIVE: To correlate measures of cerebral vascular pathology with cognitive trajectories. SETTING: Observational study. PARTICIPANTS: A cohort of 2,274 individuals who came to autopsy at a mean age of 89.3 years and 82 percent of whom had at least two cognitive assessments within the last six years of life was compiled from six centers conducting longitudinal studies. MEASUREMENTS: For each cognitive domain: immediate and delayed memory, language, and naming, three trajectories were examined: good, intermediate, and poor cognition. The probability of a participant belonging to each trajectory was associated with measures of cerebral vascular pathology after adjustment for demographics, APOE, and Alzheimer neuropathology. RESULTS: A large proportion of the cohort (72-94%) experienced good or intermediate cognition in the four domains examined. The presence of arteriolosclerosis and the presence of lacunar infarcts doubled the odds of belonging to the poor cognitive trajectory for language when compared to the good trajectory. The presence of lacunar infarcts increased the odds of an intermediate or poor trajectory for immediate and delayed recall while the presence of large artery infarcts increased the odds of poor trajectories for all four cognitive domains examined. Microinfarcts and cerebral amyloid angiopathy had little effect on the trajectories. CONCLUSION: Indicators of cerebral vascular pathology act differently on late life cognition.

Longitudinal functional alterations in asymptomatic women at risk for Alzheimer's disease.

PURPOSE: The authors sought to determine whether known alterations of brain function in normal individuals who are at high risk for Alzheimer's disease (AD) worsen or stay the same after a significant interval of time. METHODS: The authors used functional magnetic resonance imaging (fMRI) to observe cortical activation during confrontation naming in 14 women with high AD risk and 10 with low risk, based on family history and apolipoprotein-E4 allele status. They repeated the identical scan protocol in the same patients after 4 years. RESULTS: fMRI activation in high-AD-risk participants was found to be further diverged from that of their low-AD-risk counterparts over this period. CONCLUSION: fMRI may report on the presence and progression of neuropathology in the ventral temporal cortex or in functionally connected regions in presymptomatic AD.

Baseline subjective memory complaints associate with increased risk of incident dementia: the PREADVISE trial.

BACKGROUND: Subjective memory complaints reflect patient-identified deficits in memory and have been linked to increased risk of future dementia in nondemented (including cognitively intact) older adults. OBJECTIVES: To assess the risk of incident dementia during follow-up for participants in the Prevention of Alzheimer's Disease with Vitamin E and Selenium (PREADVISE) study who reported memory complaints at baseline. DESIGN: Double-blind, placebo controlled 2×2 randomized controlled trial that transformed into an observational cohort following discontinuation of supplementation in the SELECT parent trial. SETTING: PREADVISE participants were assessed at 130 local clinical study sites in the United States, Canada, and Puerto Rico during the controlled trial phase and were later followed by telephone from a centralized location during the observational phase. PARTICIPANTS: PREADVISE enrolled a total of 7,547 nondemented men over the age of 60; 4,271 consented to participation in the observational study. MEASUREMENTS: Participants were interviewed at baseline for memory complaints. The Memory Impairment Screen (MIS) was administered to each participant at the annual memory screening. Participants who failed the MIS also received a more detailed neurocognitive assessment: an expanded Consortium to Establish a Registry in Alzheimer's Disease (CERADe) neuropsychological battery was used during the RCT, and the modified Telephone Interview for Cognitive Status (TICS-m) was used during the observational study. Participants who failed the second screen were asked to have a memory work-up with a local physician and to share their medical records with PREADVISE. Subgroups of men who did not fail the MIS were also asked to complete the CERADe battery and TICS-m for validation purposes. Additional measures collected include self-reported medical history, medication use, and the AD8 Dementia Screening Test. RESULTS: After controlling for important risk factors for dementia, Cox proportional hazards regression revealed that men who reported memory changes at baseline had an 80% increase in the hazard of incident dementia compared to men who reported no SMC. Men who reported memory problems at baseline had almost a 6-fold increase in the hazard of incident dementia compared to men who reported no memory complaint. CONCLUSIONS: Memory complaints in nondemented older men predicted future dementia. Men who reported that the changes in their memory were a problem were especially at risk, and the presence of common comorbidities like diabetes, sleep apnea, and history of head injury further exacerbated this risk.

The Statistical Modeling of Aging and Risk of Transition Project: Data Collection and Harmonization Across 11 Longitudinal Cohort Studies of Aging, Cognition, and Dementia.

Longitudinal cognitive trajectories and other factors associated with mixed neuropathologies (such as Alzheimer's disease with co-occurring cerebrovascular disease) remain incompletely understood, despite being the rule and not the exception in older populations. The Statistical Modeling of Aging and Risk of Transition study (SMART) is a consortium of 11 different high-quality longitudinal studies of aging and cognition (N=11,541 participants) established for the purpose of characterizing risk and protective factors associated with subtypes of age-associated mixed neuropathologies (N=3,001 autopsies). While brain donation was not required for participation in all SMART cohorts, most achieved substantial autopsy rates (i.e., > 50%). Moreover, the studies comprising SMART have large numbers of participants who were followed from intact cognition and transitioned to cognitive impairment and dementia, as well as participants who remained cognitively intact until death. These data provide an exciting opportunity to apply sophisticated statistical methods, like Markov processes, that require large, well-characterized samples. Thus, SMART will serve as an important resource for the field of mixed dementia epidemiology and neuropathology.

Alzheimer neuropathologic alterations in aged cognitively normal subjects.

The histopathologic changes distinguishing early Alzheimer disease (AD) from normal or pathologic aging are not clearly defined. This report describes the autopsy findings of 59 elderly, well-educated, volunteers. They were examined longitudinally with mental status testing, some for up to 8 years, as part of our normal aging study. This study reveals that (1) the brains of many subjects who did not show cognitive impairment on neuropsychologic testing contain abundant senile plaques (SP) and/or neurofibrillary tangles (NFT); (2) 29 subjects met Khachaturian criteria for AD, 15 met CERAD and 7 met National Institute on Aging-Reagan Institute guidelines; (3) Braak and Braak staging method included 9 in stage IV subjects, 4 in stage V, and 1 in stage VI; (4) there was a progression of NFT from entorhinal cortex to hippocampus and amygdala as a function of age; (5) 2 subjects met criteria for a diagnosis of dementia with Lewy bodies but were not demented; (6) cerebral amyloid angiopathy was present in leptomeningeal vessels in 75% of subjects and in parenchymal vessels in 62% of subjects; (7) only 10 of 59 subjects (17%) had no or few degenerative brain changes. Our study demonstrates that the brains of a large percentage of cognitively normal, relatively well-educated individuals contain numerous degenerative changes and only a small percentage are relatively free of these changes.

"Preclinical" AD revisited: neuropathology of cognitively normal older adults.

OBJECTIVE: To classify neuropathologic alterations in the brains of nondemented older adults using current sets of criteria for AD. BACKGROUND: AD neuropathologic alterations are found in the brains of some nondemented elderly subjects and suggest the possibility of presymptomatic AD. Three sets of guidelines have been developed to classify AD using senile plaques, neuritic plaques, and neurofibrillary tangles (NFT). METHODS: Neuropathologic changes in 59 older adults followed longitudinally with a standard battery of mental status measures were investigated using Khachaturian, Consortium to Establish a Registry for Alzheimer's Disease (CERAD), and National Institute on Aging-Reagan Institute (NIA-RI) guidelines. AD neuropathologic markers were evaluated in neocortical and allocortical regions. Cases were categorized as neuropathologically "normal" or "AD-like" and compared for possible mental status differences. RESULTS: Between 11 and 49% of cases met one or more of the three classifications of AD. With adjustments for multiple comparisons, only NFT in hippocampal CA1 region were associated with autopsy age, suggesting that this may represent a pathologic process associated with normal brain aging. Using the NIA-RI guidelines, subjects in the AD-like group performed less well on the immediate paragraph recall and word-list delayed recall than their counterparts who did not meet these guidelines. CONCLUSIONS: These data indicate that the prevalence of "preclinical" AD in our population is relatively low based on the NIA-RI classification. Although many subjects had AD-like changes based on CERAD and Khachaturian guidelines, they exhibited no differences in mental performance, suggesting that the aging brain may be able to withstand such structural changes without meaningful impact on mental functioning.

Women at risk for AD show increased parietal activation during a fluency task.

BACKGROUND: Imaging studies have shown disparities in resting metabolism and in functional activation between cognitively normal individuals at high and low risk for AD. A recent study has shown increased parietal activation in high-risk subjects during a paired associates recall task, which the authors postulated might overlap activation typically observed in verbal fluency. OBJECTIVE: To determine whether parietal activation is altered in a letter fluency task in cognitively normal individuals at high risk for AD. METHODS: fMRI was used to compare cortical activation between two groups of cognitively normal women differing in their risk for developing AD. A letter fluency task was used, which activates left frontal and parietal regions. The risk groups differed in family history of AD and APOE allele status but were matched in age, education, and measures of cognitive performance. Average age of the study participants was 53 years. RESULTS: The regional patterns of brain activation were similar between groups and similar to patterns observed by other investigators. However, the high-risk group showed significantly increased activation in the left parietal region despite identical letter fluency performance between risk groups. CONCLUSIONS: Cognitively normal individuals at high risk for AD show increased brain activation in the left parietal region with letter fluency, a region adjacent to that observed by others using a recall task. This convergence of results indicates disruption of functional circuits involving the left parietal lobe in asymptomatic individuals at increased risk for AD.

Altered brain activation in cognitively intact individuals at high risk for Alzheimer's disease.

OBJECTIVE: To determine whether brain function is altered in cognitively normal individuals at high risk for AD several years before the typical age at onset for this illness. BACKGROUND: Neuropathologic alterations in AD precede cognitive impairment by several years. It is unknown whether functional alterations in neural circuitry accompany these neuropathologic changes, and if so, whether they may be detectable before onset of symptoms. METHODS: We used functional MRI to compare cortical activation between two groups of cognitively normal women differing only in their risk for developing AD. Visual naming and letter fluency tasks were used to activate brain areas subserving object and face recognition, previously described sites of hypometabolism and neuropathologic alteration in AD. The risk groups differed in family history of AD and apolipoprotein E allele status, but were matched in age, education, and measures of cognitive performance. Average age of the study participants was 52 years. RESULTS: The regional patterns of brain activation were similar between groups. However, the high risk group showed areas of significantly reduced activation in the mid- and posterior inferotemporal regions bilaterally during both tasks despite identical naming and letter fluency performance. CONCLUSIONS: Cognitively normal individuals at high risk for AD demonstrate decreased brain activation in key areas engaged during naming and fluency tasks. Decreased activation in the high risk group may be a consequence of the presence of subclinical neuropathology in the inferotemporal region or in the inputs to that region. If so, these findings provide evidence of a window of opportunity for disease-modifying treatment before the onset of symptomatic AD.

Critical decline in fine motor hand movements in human aging.

BACKGROUND: Slowing of motor movements in human aging is a well-known occurrence, but its biologic basis is poorly understood. Reliable quantitation may refine observations of this phenomenon to better aid research on this entity. METHODS: A panel equipped with timing sensors under computer control was used to measure upper extremity movement times in two groups of healthy individuals: adults younger than 60 years of age (n = 56; range, 18-58 years) and adults older than 60 years of age (n = 38; range, 61-94 years). RESULTS: Fine motor performance was better in the dominant hand (p = 0.0007) regardless of age. Adult and aged groups differed on two basic timing measures, which reflect coarse motor and fine motor performance (p < 0.0001). There were no gender differences on either measure. There was a strong effect of task difficulty with age on coarse motor (p < 0.01) and fine motor (p < 0.0001) measures. The fine motor measure of hand performance in healthy individuals correlated in a nonlinear fashion with age for more difficult tasks (r2 = 0.63) but showed a simple linear relation for less-demanding tasks (r2 = 0.5). CONCLUSION: This technique sensitively detects age-related motor performance decline in humans. There may be a critical period in late midlife when fine motor performance decline either begins or abruptly worsens.

Single SPECT measures of cerebral cortical perfusion reflect time-index estimation of dementia severity in Alzheimer's disease.

UNLABELLED: To determine the relationship between cerebral cortical blood flow loss and the temporal development of the dementia in Alzheimer's disease (AD), SPECT was studied in a cross section of AD patients with a broad range of impairment. METHODS: Thirty patients with a diagnosis of probable AD had their mini-mental state examination scores transformed into time-index values to give an estimation of dementia severity relative to the developmental time course. SPECT images were obtained using 99mTc-ethyl cysteinate dimer and a 3-head camera. Cortical surface perfusion was analyzed, including modified Talairach standardization, to obtain cortical elements from the convexity (each representing about 0.25 cm2 at the surface, 6.6-mm cortical depth) referenced to the mean perfusion of the full greater cerebellar hemisphere. These element ratios were analyzed (individually and by averages of estimated Brodmann's areas and brain regions) using linear regression with the time-index value. RESULTS: For individual posterotemporal and inferoparietal Brodmann's areas (21, 22 and 39, 40, respectively) the correlation coefficients between cortical perfusion ratios and dementia severity ranged between -0.67 and -0.78 (P < 0.001). Perfusion ratios from these regions declined 2.5%-4.2% for each estimated year of progression. Prefrontal area perfusion showed less association with severity. Perfusion in primary cortical regions had no significant association with dementia severity. CONCLUSION: Cerebral cortical perfusion loss is temporally related to development of dementia. The spatial pattern of high, significant correlations between cortical perfusion and dementia severity shows a regional distribution that corresponds closely to the distribution of AD pathology described in autopsy studies.