Comparison between DSQIID total/sub‐item scores and plasma p‐tau elevation in adults with Down syndrome

Abstract

AbstractBackgroundPeople with Down syndrome (DS) are at a high risk of developing Alzheimer’s disease (AD) with aging. The Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) is an appropriate screening tool for detecting dementia in DS. However, it remains unclear whether this questionnaire genuinely reflects the neuropsychiatric signs of DS‐AD with biomarker‐based diagnoses.MethodTo validate the usefulness of DSQIID for detecting DS‐AD, we conducted this cross‐sectional observational study comparing plasma tau phosphorylated at the threonine 181 residue (p‐tau) level of a representative AD biomarker to the total score and each sub‐item score of the DSQIID. Plasma p‐tau levels and apolipoprotein E (ApoE) types were determined in 56 individuals with DS. Among these patients, 43 completed the DSQIID. Thirty‐three controls were enrolled to set the reference value for plasma p‐tau levels.ResultsThe plasma p‐tau level in the DS group was age‐dependently elevated and reached an abnormal cut‐off over the age of 40 years. Age‐related elevation of p‐tau level was steeper in DS individuals with the ApoE4 allele than in those without ApoE4, validating the usefulness of plasma p‐tau as a surrogate indicator of AD‐DS development. In contrast, although DSQIID total and some sub‐item scores were positively correlated with plasma p‐tau level, all these significant correlations disappeared after age adjustment. Moreover, two sub‐items, “Talks to self” and “Generally appears more forgetful,” were significantly negatively correlated with plasma p‐tau level after age‐adjustment.ConclusionThese results suggest that there is room for improvement in DSQIID for detecting DS‐AD.