Relationship Between P‐tau217 and Subjective Sleep Quality in MCI and Mild AD. A Preliminary Study

Abstract

AbstractBackgroundPlasma‐tau217 (ptau217) has recently emerged as a biomarker for Alzheimer’s disease (AD). With sleep changes as an established feature of AD, previous studies suggest a link between sleep and tau pathology. We investigated whether overall subjective estimation of sleep quality is associated with p‐tau217 concentration (pg/ml) in a small sample population of older adults with mild cognitive impairment (MCI) or mild Alzheimer’s disease (AD).MethodWe examined participants (mean age = 69) with MCI (n = 14) and mild AD (n = 2). MCI participants had CDR 0.5 and MoCA scores ranging 17‐28. Mild AD participants had CDR of 1.0 and MoCA scores of 17. pTau217 was measured with a novel validated SIMOA assay, developed by one of us (A.J.) for ALZPath, Inc. The Pittsburgh Sleep Quality Index (PSQI) was used as a subjective measure of sleep quality. Pearson correlation coefficient was used to test the association between ptau217 and the global score of PSQI, and spearman’s rho was used for each of the 7 subscales of the PSQI.ResultThe global score (total score) of the PSQI was found to be significantly correlated with ptau217 concentration, such that poorer sleep was associated with increased ptau217 (r = ‐.587, p<.05). Partial correlations revealed that this correlation remained after controlling for age, sex, and years of education (all p<.05).ConclusionGlobal scores on the PSQI were associated with ptau217 concentration in MCI and mild AD participants, such that poor reported sleep quality was associated with increased plasma tau. Future studies in larger samples and longitudinal investigations using objective sleep data (actigraphs) would serve to confirm these findings.