Performance variability during a multitrial list-learning task as a predictor of future cognitive decline in healthy elders

Abstract

Introduction In clinical settings, neuropsychological test performance is traditionally evaluated with total summary scores (TSS). However, recent studies demonstrated that indices of intraindividual variability (IIV) yielded unique information complementing TSS. This 18-month longitudinal study sought to determine whether IIV indices derived from a multitrial list-learning test (the Rey Auditory Verbal Learning Test) provided incremental utility in predicting cognitive decline in older adults compared to TSS. Method Ninety-nine cognitively intact older adults (aged 65 to 89 years) underwent neuropsychological testing (including the Rey Auditory Verbal Learning Test) at baseline and 18-month follow-up. Participants were classified as cognitively stable (n = 65) or declining (n = 34) based on changes in their neuropsychological test performance. Logistic regression modeling tested the ability of baseline TSS indices (Sum of Trials 1-5, Immediate Recall, and Delayed Recall) and IIV indices (Lost Access and Gained Access) to discriminate between stable and declining individuals. Results Higher values of both Lost Access and Gained Access at baseline were associated with an increased risk for decline at 18-month follow-up. Further, the IIV indices provided predictive utility above and beyond the TSS indices. Conclusion These results highlight the value of analyzing IIV in addition to TSS during neuropsychological evaluation in older adults. High levels of IIV may reflect impairment in anterograde memory systems and/or executive dysfunction that may serve as a prognostic indicator of cognitive decline.

Subcortical Ischemic Vascular Cognitive Impairment: Insights from Reaction Time Measures

“…Although the underlying cause for this pattern of results remains to be determined, they indicate that improvement in RT can in fact mask an abnormally high degree of IIV. Because IIV appears more related to disease, function, and health than RT [47,48,50,54,[57][58][59], its status may therefore (with further investigation) represent a more meaningful, relevant disease characteristic than RT in SIVCI.…”

“…In an original approach, the relationship between RT and IIV in SIVCI is also examined in this study. Furthermore, IIV appears to be particularly representative of everyday functioning, cognitive status, the risk of falls, injury, health, decline in cognitive function, impending decline, lower functionality, morbidity, and mortality [47,48,50,54,[57][58][59]. Arguably therefore, IIV may be a more sensitive or meaningful marker of SIVCI than RT alone, and one which may help to improve the functional and clinical characterization of SIVCI.…”

“…As some evidence from the study of mild cognitive impairment [88,89] indicates that individuals with slower RT or raised IIV are at greater risk of disease progression, one can speculate that SIVCI patients with particularly slow RT or high IIV, are those most at risk of disease progression, or are, in fact, at a later stage of disease than that indicated by neuropsychological and other test results. Moreover, although both RT and IIV appear similarly able to differentiate SIVCI from CH, the greater association of IIV with health and functional status [47,48,50,54,[57][58][59], indicates that IIV may be a more sensitive or meaningful characteristic of VCI than RT alone, and should therefore be measured alongside RT in clinical practice. Again, further research is required to appropriately investigate such speculation.…”

Intraindividual variability in performance on associative memory tasks is elevated in amnestic mild cognitive impairment

“…Over and above these other measures, IIV tends to uniquely predict meaningful outcomes such as everyday functioning (Burton et al, 2009), falls (Graveson et al, 2015), the presence of cognitive impairment (Collins and Long, 1996), cognitive decline (Sugarman et al, 2014), and even impending death , among others. Increased variability is seen in normal cognitive aging.…”

Motor timing intraindividual variability in amnestic mild cognitive impairment and cognitively intact elders at genetic risk for Alzheimer’s disease

“…In addition, IIV appears to predict future cognitive decline in asymptomatic elders (Bielak, Hultsch, Strauss, Macdonald, & Hunter, 2010a, 2010b; Lovden, Li, Shing, & Lindenberger, 2007; MacDonald, Hultsch, & Dixon, 2003; Sugarman et al, 2014). For example, increased IIV in simple, choice, and switching RT tasks among healthy elders was associated with a greater likelihood of being classified with greater cognitive impairment five years later (Bielak et al, 2010a).…”