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Browsing by Author "Duff, Kevin"
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Item Demographically-corrected normative data for the RBANS Learning Ratio in a sample of older adults(Taylor & Francis, 2022) Hammers, Dustin B.; Duff, Kevin; Spencer, Robert J.; Neurology, School of MedicineBackground: A novel learning slope score - the Learning Ratio (LR) - has recently been developed that appears to be sensitive to memory performance and AD pathology more optimally than traditional learning slope calculations. While promising, this research to date has been both experimental and based on group differences, and therefore does not aid in the interpretation of individual LR performance for either clinical or research settings. The objective of the current study was to develop demographically-corrected normative data on these LR learning slopes on verbal learning measures from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Method: The current study examined the influence of age and education on LR metrics for the List Learning, Story Memory, and an Aggregated RBANS score in 200 cognitively intact adults aged 65 or older using linear regression. Results: Age and education correlated with most LR metrics, but no sex differences were observed. Linear regression permitted the prediction of LR values from age and education, which are then compared to observed LR values. The result is demographically-corrected T scores for these LR metrics. Conclusions: By comparing observed and predicted LR scores calculated from regression-based prediction equations, this represents the first step towards interpretation of individual performances on this metric for clinical decision making and treatment planning purposes. With future replication in diverse and heterogenous samples, we hope to offer a new clinical tool for the examination of learning slopes in older adults.Item Examining the role of repeated test exposure over 12 months across ADNI protocols(Wiley, 2022) Hammers, Dustin B.; Duff, Kevin; Apostolova, Liana G.; Alzheimer's Disease Neuroimaging Initiative; Neurology, School of MedicineObjective: Changes to study protocols during longitudinal research may alter cognitive testing schedules over time. Unlike in prior Alzheimer's Disease Neuroimaging Initiative (ADNI) protocols, where testing occurred twice annually, participants enrolled in the ADNI-3 are no longer exposed to cognitive materials at 6 months. This may affect their 12-month performance relative to earlier ADNI cohorts, and potentially confounds data harmonization attempts between earlier and later ADNI protocols. Method: Using data from participants enrolled across multiple ADNI protocols, this study investigated whether test exposure during 6-month cognitive evaluation influenced scores on subsequent 12-month evaluation. Results: No interaction effects were observed between test exposure group and time at 12 months on cognitive performance. No improvements, and limited declines, were seen between baseline and 12-month follow-up scores on most measures. Conclusions: The 6-month testing session had minimal impact on 12-month performance in ADNI. Collapsing longitudinal data across ADNI protocols in future research appears appropriate.Item Predicting daily functioning with the modified Telephone Interview for Cognitive Status(Springer Nature, 2022) Dixon, Ava; Porter, Sariah; Suhrie, Kayla; Hammers, Dustin; Duff, Kevin; Neurology, School of MedicineBackground: The modified Telephone Interview for Cognitive Status (mTICS) is a frequently used telephone-based cognitive screening measure that can distinguish between normal aging, mild cognitive impairment (MCI), and dementia. Although it has been used to predict current and future cognitive function in older adults, no studies have examined if the mTICS can predict daily functioning. Aims: The current study sought to examine the relationship between the mTICS and a performance-based measure of daily functioning. Methods: The mTICS and demographic information (age, sex, education) were collected during a telephone screening visit for 149 older adults (65-91 years in age) with amnestic MCI. Three subscales of the Independent Living Scales (ILS; Managing Money, Managing Home and Transportation, Health and Safety) were collected during a baseline visit and during a 16 month follow-up visit in a subsample of 93 individuals. Results: Using simple hierarchical regression, baseline mTICS total score combined with demographic variables significantly predicted 19-22% of baseline ILS subscale scores. Similarly, in a subsample of 93 participants with 16 month follow-up data, baseline mTICS and demographic information predicted 9-31% of ILS subscale scores at follow-up. Conclusions: The mTICS appears able to predict daily functioning in older individuals with MCI. Remote tracking of cognition and daily functioning in this at-risk group seems particularly beneficial to geriatricians and other providers, especially during COVID-19.Item The Quick Dementia Rating System and Its Relationship to Biomarkers of Alzheimer's Disease and Neuropsychological Performance(Karger, 2022) Duff, Kevin; Wan, Laura; Levine, Deborah A.; Giordani, Bruno; Fowler, Nicole R.; Fagerlin, Angela; King, Jace B.; Hoffman, John M.; Medicine, School of MedicineIntroduction: The Quick Dementia Rating System (QDRS) is a brief, patient-reported dementia staging tool that has approximated scores on the Clinical Dementia Rating Scale in patients with Alzheimer's disease (AD). However, no studies have examined its relationship with AD-related biomarkers. Methods: One-hundred twenty-one older adults (intact, amnestic mild cognitive impairment, mild AD) completed the QDRS, and three biomarkers (amyloid deposition via positron emission tomography, hippocampal volume via magnetic resonance imaging, and apolipoprotein [APOE] ε4 status). Results: The Total score on the QDRS was statistically significantly related to all three biomarkers (after controlling for age, education, sex, and race), with greater levels of dementia severity being associated with greater amyloid deposition, smaller hippocampi, and having copies of APOE ε4 allele. Discussion: In participants across the cognitive spectrum, the QDRS showed modest relationships with amyloid deposition, hippocampal volumes, and APOE status. Therefore, the QDRS may offer a cost-effective screening method for clinical trials in AD.