Dependence Clusters in Alzheimer Disease and Medicare Expenditures: A Longitudinal Analysis From the Predictors Study.

INTRODUCTION: Dependence in Alzheimer disease has been proposed as a holistic, transparent, and meaningful representation of disease severity. Modeling clusters in dependence trajectories can help understand changes in disease course and care cost over time. METHODS: Sample consisted of 199 initially community-living patients with probable Alzheimer disease recruited from 3 academic medical centers in the United States followed for up to 10 years and had ≥2 Dependence Scale recorded. Nonparametric K-means cluster analysis for longitudinal data (KmL) was used to identify dependence clusters. Medicare expenditures data (1999-2010) were compared between clusters. RESULTS: KmL identified 2 distinct Dependence Scale clusters: (A) high initial dependence, faster decline, and (B) low initial dependence, slower decline. Adjusting for patient characteristics, 6-month Medicare expenditures increased over time with widening between-cluster differences. DISCUSSION: Dependence captures dementia care costs over time. Better characterization of dependence clusters has significant implications for understanding disease progression, trial design and care planning.

Neural correlates of people's hypercorrection of their false beliefs.

Despite the intuition that strongly held beliefs are particularly difficult to change, the data on error correction indicate that general information errors that people commit with a high degree of belief are especially easy to correct. This finding is called the hypercorrection effect. The hypothesis was tested that the reason for hypercorrection stems from enhanced attention and encoding that results from a metacognitive mismatch between the person's confidence in their responses and the true answer. This experiment, which is the first to use imaging to investigate the hypercorrection effect, provided support for this hypothesis, showing that both metacognitive mismatch conditions-that in which high confidence accompanies a wrong answer and that in which low confidence accompanies a correct answer-revealed anterior cingulate and medial frontal gyrus activations. Only in the high confidence error condition, however, was an error that conflicted with the true answer mentally present. And only the high confidence error condition yielded activations in the right TPJ and the right dorsolateral pFC. These activations suggested that, during the correction process after error commission, people (1) were entertaining both the false belief as well as the true belief (as in theory of mind tasks, which also manifest the right TPJ activation) and (2) may have been suppressing the unwanted, incorrect information that they had, themselves, produced (as in think/no-think tasks, which also manifest dorsolateral pFC activation). These error-specific processes as well as enhanced attention because of metacognitive mismatch appear to be implicated.

Do neuropsychological tests have the same meaning in Spanish speakers as they do in English speakers?

OBJECTIVE: The purpose of this study was to examine whether neuropsychological tests translated into Spanish measure the same cognitive constructs as the original English versions. METHOD: Older adult participants (N = 2,664), who did not exhibit dementia from the Washington Heights Inwood Columbia Aging Project (WHICAP), a community-based cohort from northern Manhattan, were evaluated with a comprehensive neuropsychological battery. The study cohort includes both English (n = 1,800) and Spanish speakers (n = 864) evaluated in their language of preference. Invariance analyses were conducted across language groups on a structural equation model comprising four neuropsychological factors (memory, language, visual-spatial ability, and processing speed). RESULTS: The results of the analyses indicated that the four-factor model exhibited partial measurement invariance, demonstrated by invariant factor structure and factor loadings but nonequivalent observed score intercepts. CONCLUSION: The finding of invariant factor structure and factor loadings provides empirical evidence to support the implicit assumption that scores on neuropsychological tests are measuring equivalent psychological traits across these two language groups. At the structural level, the model exhibited invariant factor variances and covariances.

Food combination and Alzheimer disease risk: a protective diet.

OBJECTIVE: To assess the association between food combination and Alzheimer disease (AD) risk. Because foods are not consumed in isolation, dietary pattern (DP) analysis of food combination, taking into account the interactions among food components, may offer methodological advantages. DESIGN: Prospective cohort study. SETTING: Northern Manhattan, New York, New York. PATIENTS OR OTHER PARTICIPANTS: Two thousand one hundred forty-eight community-based elderly subjects (aged > or = 65 years) without dementia in New York provided dietary information and were prospectively evaluated with the same standardized neurological and neuropsychological measures approximately every 1.5 years. Using reduced rank regression, we calculated DPs based on their ability to explain variation in 7 potentially AD-related nutrients: saturated fatty acids, monounsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-6 polyunsaturated fatty acids, vitamin E, vitamin B(12), and folate. The associations of reduced rank regression-derived DPs with AD risk were then examined using a Cox proportional hazards model. Main Outcome Measure Incident AD risk. RESULTS: Two hundred fifty-three subjects developed AD during a follow-up of 3.9 years. We identified a DP strongly associated with lower AD risk: compared with subjects in the lowest tertile of adherence to this pattern, the AD hazard ratio (95% confidence interval) for subjects in the highest DP tertile was 0.62 (0.43-0.89) after multivariable adjustment (P for trend = .01). This DP was characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables and a lower intake of high-fat dairy products, red meat, organ meat, and butter. CONCLUSION: Simultaneous consideration of previous knowledge regarding potentially AD-related nutrients and multiple food groups can aid in identifying food combinations that are associated with AD risk.

The brain's orienting response: An event-related functional magnetic resonance imaging investigation.

An important function of the brain's orienting response is to enable the evaluation of novel, environmental events in order to prepare for potential behavioral action. Here, we assessed the event-related hemodynamic (erfMRI) correlates of this phenomenon using unexpected (i.e., novel) environmental sounds presented within the context of an auditory novelty oddball paradigm. In ERP investigations of the novelty oddball, repetition of the identical novel sound leads to habituation of the novelty P3, an ERP sign of the orienting response. Repetition also leads to an enhancement of a subsequent positivity that appears to reflect semantic analysis of the environmental sounds. In this adaptation for erfMRI recording, frequent tones were intermixed randomly with infrequent target tones and equally infrequent novel, environmental sounds. Subjects responded via speeded button press to targets. To assess habituation, some of the environmental sounds were repeated two blocks after their initial presentation. As expected, novel sounds and target tones led to activation of widespread, but somewhat different, neural networks. Contrary to expectation, however, there were no significant areas in which activation was reduced in response to second compared to first presentations of the novel sounds. Conversely, novel sounds relative to target tones engendered activity in the inferior frontal gyrus (BA 45) consistent with semantic analysis of these events. We conclude that a key concomitant of the orienting response is the extraction of meaning, thereby enabling one to determine the significance of the environmental perturbation and take appropriate goal-directed action.