Reduced Slow-Wave Sleep Is Associated with High Cerebrospinal Fluid A beta 42 Levels in Cognitively Normal Elderly

Study Objectives: Emerging evidence suggests a role for sleep in contributing to the progression of Alzheimer disease (AD). Slow wave sleep (SWS) is the stage during which synaptic activity is minimal and clearance of neuronal metabolites is high, making it an ideal state to regulate levels of amyloid beta (Aβ). We thus aimed to examine relationships between concentrations of Aβ42 in the cerebrospinal fluid (CSF) and measures of SWS in cognitively normal elderly subjects. Methods: Thirty-six subjects underwent a clinical and cognitive assessment, a structural MRI, a morning to early afternoon lumbar puncture, and nocturnal polysomnography. Correlations and linear regression analyses were used to assess for associations between CSF Aβ42 levels and measures of SWS controlling for potential confounders. Resulting models were compared to each other using ordinary least squared linear regression analysis. Additionally, the participant sample was dichotomized into “high” and “low” Aβ42 groups to compare SWS bout length using survival analyses. Results: A significant inverse correlation was found between CSF Aβ42 levels, SWS duration and other SWS characteristics. Collectively, total SWA in the frontal lead was the best predictor of reduced CSF Aβ42 levels when controlling for age and ApoE status. Total sleep time, time spent in NREM1, NREM2, or REM sleep were not correlated with CSF Aβ42. Conclusions: In cognitively normal elderly, reduced and fragmented SWS is associated with increases in CSF Aβ42, suggesting that disturbed sleep might drive an increase in soluble brain Aβ levels prior to amyloid deposition

An Extended Joint Consistency Theorem for a Nonconstructive Logic Of . . .

The logic of partial terms (LPT) is a variety of negative free logic in which functions, as well as predicates, are strict. A companion paper focused on nonconstructive LPT with de nite descriptions, called LPD, and laid the foundation for tableaux systems by de ning the concept of an LPD model system and establishing Hintikka's Lemma, from which the strong completeness of the corresponding tableaux system readily follows. The present paper utilizes the tableaux system in establishing an Extended Joint Consistency Theorem for LPD that incorporates the Robinson Joint Consistency Theorem and the Craig-Lyndon Interpolation Lemma. The method of proof is similar to that originally used in establishing the Extended Joint Consistency Theorem for positive free logic. Proof of the Craig-Lyndon Interpolation Lemma for formulas possibly having free variables is readily had in LPT and its intuitionistic counterpart. The paper concludes with a brief discussion of the theory of definitions in LPD

A Free Logical Foundation for Nonstrict Functions

this paper, we sketch the definition theory for a nonstrict positive free logic in which there is exactly one error object err to which all terms without existential import can refer. Having exactly one error object identifies nontermination and all run-time errors. This is most natural in languages such as Miranda and haskell in which execution is aborted immediately when an error is raised [16]. By using a free logic, we are able to state the axioms of a mathematical theory without cluttering the axiomatization with error conditions, as would be required using restricted quantification in standard logic. For example, Peano's axiom