Dispersion-based cognitive intra-individual variability in dementia with Lewy bodies.

Abstract

Objective: Cognitive fluctuations are characteristic of dementia with Lewy bodies (DLB) but challenging to measure. Dispersion-based intra-individual variability (IIV-d) captures neurocognitive performance fluctuations across a test battery and may be sensitive to cognitive fluctuations but has not been studied in DLB. Method: We report on 5,976 participants that completed the uniform data set 3.0 neuropsychological battery (UDS3NB). IIV-d was calculated via the intra-individual standard deviation across 12 primary UDS3NB indicators. Separate models using mean USD3NB score and the Montreal cognitive assessment (MoCA) total score tested the reproducibility of the incremental value of IIV-d over-and-above global cognition. Binary logistic regressions tested whether IIV-d could classify individuals with and without clinician-rated cognitive fluctuations. Multinomial logistic regressions tested whether IIV-d could differentiate participants with DLB, participants with Alzheimer’s disease (AD), and participants with healthy cognition (CH), as well as the incremental diagnostic utility of IIV-d over-and-above clinician-rated cognitive fluctuations. Results: IIV-d exhibited large univariate associations with clinician-rated and non-clinician-informant reported cognitive fluctuations, which persisted when adjusting for MoCA but not the full battery mean. Of diagnostic relevance, greater IIV-d was consistently associated with DLB and AD relative to CH over-and-above global cognition and clinician-rated cognitive fluctuations. Greater IIV-d was less consistently associated with an increased probability of DLB relative to AD when controlling for global cognition. Conclusions: IIV-d accurately differentiates DLB from CH over-and-above global cognition and clinician-rated cognitive fluctuations. IIV-d may supplement a thorough clinical interview of cognitive fluctuations and serve as a standardized performance-based indicator of this transdiagnostic phenomenon.

Ecological validity of cognitive fluctuations in dementia with Lewy bodies

“…Consistent with previous research (Webber et al, 2022), the current study also provides evidence that intraindividual variability-dispersion in the laboratory or clinic predicts the presence of daily cognitive fluctuations in DLB at a large effect size (Odds Ratio = 73.27). However, the current study builds on this work by controlling for global cognition while testing the association of intraindividual variability-dispersion and daily cognitive fluctuations in a larger and strictly DLB sample.…”

“…To this end, the goals of this study were to (1) test the association of intraindividual variability-dispersion and informant-rated daily cognitive fluctuations in DLB, (2) examine the relationship between intraindividual variability-dispersion and daily functioning in DLB, and (3) test the incremental utility of clinician-rated cognitive fluctuations, informant-rated daily cognitive fluctuations, and intraindividual variability-dispersion for predicting daily functioning. Consistent with previous research (Webber et al, 2022), a positive relationship between intraindividual variability-dispersion and probability of informant-rated daily cognitive fluctuations was expected. Given evidence for substandard reliability of clinical interviews for detecting cognitive fluctuations in DLB (Litvan et al, 1998; Mega et al, 1996), we expected informant-ratings on the MFS to incrementally predict daily functioning over-and-above clinician-ratings of cognitive fluctuations.…”

“…Only one study known to these authors has examined intraindividual variability-dispersion in DLB. In this study, intraindividual variability-dispersion derived from a battery of 12 neurocognitive tasks was consistently higher in both AD and DLB than in individuals with healthy cognition (Webber et al, 2022). Further, intraindividual variability-dispersion was associated with clinician-rated cognitive fluctuations at a large effect size magnitude ( d = .79).…”

“…Additional exclusion criteria and the resulting final sample of 97 participants are depicted via STROBE (Strengthening the Reporting of OBservational studies in Epidemiology) diagram in Figure 1. Of note, 35 participants (36% of the current sample) were included in recent work on intraindividual variability-dispersion in DLB (Webber et al, 2022), though relationships between some variables in this study (i.e., intraindividual variability-dispersion and MFS) were previously reported for only 26 participants (27% of the current sample) due to differing inclusion/exclusion criteria and regular data entry updates.…”

Lower prospective memory is associated with higher neurocognitive dispersion in two samples of people with HIV: A conceptual replication study

“…IIV is commonly measured by calculating the variability within repeated measures of the same cognitive test (i.e., IIV-inconsistency, typically in response time) or by variability across different cognitive tests (i.e., IIV-dispersion). In this study, we focus on IIV-dispersion, which is associated with increased risk of incipient cognitive decline (e.g., Jones et al, 2018) and is elevated in cross-sectional samples of older adults (e.g., Hilborn et al, 2009) and in persons with Huntington’s disease (Musso et al, 2015), traumatic brain injury (TBI; Hill et al, 2013), Dementia with Lewy Bodies (Webber et al, in press), and viral infection (Morgan et al, 2012; Sheppard et al, 2020). Higher IIV-dispersion has been linked to poorer microstructural integrity of white matter pathways in older adults (Halliday et al, 2019) and persons with mild TBI (Sorg et al, 2021), particularly the genu and the superior longitudinal fasciculus.…”