Validating 1-Year Reliable Change Methods

Longitudinal normative standards for cognitive tests and composites using harmonized data from two Wisconsin AD-risk-enriched cohorts

INTRODUCTION

Published norms are typically cross-sectional and often are not sensitive to preclinical cognitive changes due to dementia. We developed and validated demographically adjusted cross-sectional and longitudinal normative standards using harmonized outcomes from two Alzheimer's disease (AD) risk-enriched cohorts.

METHODS

Data from the Wisconsin Registry for Alzheimer's Prevention and the Wisconsin Alzheimer's Disease Research Center were combined. Quantile regression was used to develop unconditional (cross-sectional) and conditional (longitudinal) normative standards for 18 outcomes using data from cognitively unimpaired participants (N = 1390; mean follow-up = 9.25 years). Validity analyses (N = 2456) examined relationships between percentile scores (centiles), consensus-based cognitive statuses, and AD biomarker levels.

RESULTS

Unconditional and conditional centiles were lower in those with consensus-based impairment or biomarker positivity. Similarly, quantitative biomarker levels were higher in those whose centiles suggested decline.

DISCUSSION

This study presents normative standards for cognitive measures sensitive to pre-clinical changes. Future directions will investigate potential clinical applications of longitudinal normative standards.

HIGHLIGHTS

Quantile regression was used to construct longitudinal norms for cognitive tests. Poorer percentile scores were related to concurrent diagnosis and Alzheimer's disease biomarkers. A ShinyApp was built to display test scores and norms and flag low performance.

Preventing cognitive decline by reducing BP target (PCOT): A randomized, pragmatic, multi-health systems clinical trial

BACKGROUND

Growing evidence suggests that intensive lowering of systolic blood pressure (BP) may prevent mild cognitive impairment (MCI) and dementia. However, current guidelines provide inconsistent recommendations regarding optimal BP targets, citing safety concerns of excessive BP lowering in the diverse population of older adults. We are conducting a pragmatic trial to determine if an implementation strategy to reduce systolic BP to <130 and diastolic BP to <80 mmHg will safely slow cognitive decline in older adults with hypertension when compared to patients receiving usual care.

METHODS

The Preventing Cognitive Decline by Reducing BP Target Trial (PCOT) is an embedded randomized pragmatic clinical trial in 4000 patients from two diverse health-systems who are age ≥ 70 years with BP >130/80 mmHg. Participants are randomized to the intervention arm or usual care using a permuted block randomization within each health system. The intervention is a combination of team-based care with clinical decision support to lower home BP to <130/80 mmHg. The primary outcome is cognitive decline as determined by the change in the modified Telephone Interview for Cognitive Status (TICS-m) scores from baseline. As a secondary outcome, patients who decline ≥3 points on the TICS-m will complete additional cognitive assessments and this information will be reviewed by an expert panel to determine if they meet criteria for MCI or dementia.

CONCLUSION

The PCOT trial will address the effectiveness and safety of hypertension treatment in two large health systems to lower BP targets to reduce risk of cognitive decline in real-world settings.

Reliable Cognitive Decline in Late-Life Major Depression

OBJECTIVE

Major depression in older adults increases the statistical likelihood of dementia. It is challenging to translate statistical evidence of cognitive decline at the group level into knowledge of individual cognitive outcomes. The objective of the current study is to investigate 2-year reliable cognitive change in late-life depression (LLD), which will enhance understanding of cognitive changes in LLD and provide a means to assess individual change.

METHODS

In a sample of non-depressed cognitively normal older adults or NDCN (n = 113), we used linear regression to predict tests of global cognition, processing speed-executive functioning, and memory administered 1 and 2 years later. Stepwise regression was used to select covariates among demographics and raw test scores (either baseline or year 1) and we cross-validated the final models using the predicted residual error sum of squares (PRESS). We then derived a z-change score from the difference between actual and predicted follow-up scores and investigated the proportion of LLD patients (n = 199) and NDCN adults who experienced reliable "decline" (a z-score < -1.645), "stability" (z-scores between + - 1.645), and "improvement" (z scores > +1.645).

RESULTS

A greater proportion LLD compared with NDCN experienced cognitive decline in processing speed/executive functioning and global cognition over 2 years. When compared to NDCN, a greater proportion of LLD also significantly improved on one test of processing speed over 2 years.

CONCLUSIONS

Older adults with LLD are at risk of meaningful cognitive decline over a relatively short period, particularly in the domain of executive functioning and processing speed. This study provides a series of reliable change equations for common neuropsychological tests that can be applied clinically.

Evaluating the Impact of Cochlear Implantation on Cognitive Function in Older Adults

OBJECTIVES/HYPOTHESIS

We hypothesize that treating hearing loss through cochlear implantation in older adults will improve cognitive function.

STUDY DESIGN

Prospective, interventional study.

METHODS

Thirty-seven participants aged 65 years and older who met criteria for cochlear implantation were enrolled. Subjects underwent preoperative cognitive testing with a novel arrangement of standard neuropsychological tests, including tests of general cognition and mood (Mini-Mental Status Exam [MMSE]), tests of verbally based stimuli and responses (Digit Span, Stroop, Hopkins Verbal Learning Test-Revised [HVLT-R], Hayling Sentence Completion), and comparable visually based tests (Spatial Span, d2 Test of Attention, Brief Visuospatial Memory Test [BVMT], Trails A and B). Testing was repeated 12 months postoperatively.

RESULTS

One year postoperatively, subjects showed a statistically significant improvement in hearing and on the following tests of cognitive function: concentration performance of the d2 Test of Attention, Hayling Sentence Completion Test, HVLT-R (total and delayed recall), Spatial Span (backward), and Stroop Color Word Test. A subgroup analysis was performed comparing 13 participants with preoperative cognitive impairment (MMSE ≤ 24) to 24 participants with normal cognition (MMSE ≥ 25). In this subgroup analysis, a greater magnitude of improvement was seen in those with impaired cognition, with statistically significant improvement in Digit Span (scaled score), Stroop Word (T-score), Stroop Color-Word (residual and T-score), HVLT-R, and Hayling (overall). All verbally based test scores improved, and 75% of the visually based test scores improved.

CONCLUSIONS

This study demonstrates the cognitive benefits of cochlear implantation in older adults 1 year after surgery. For older adults with cognitive impairment prior to cochlear implantation, the cognitive benefits were even greater than in subjects with normal cognition.

LEVEL OF EVIDENCE

3, nonrandomized controlled cohort Laryngoscope, 132:S1-S15, 2022.