Unsupervised high-frequency smartphone-based cognitive assessments are reliable, valid, and feasible in older adults at risk for Alzheimer's disease.

OBJECTIVE: Smartphones have the potential for capturing subtle changes in cognition that characterize preclinical Alzheimer's disease (AD) in older adults. The Ambulatory Research in Cognition (ARC) smartphone application is based on principles from ecological momentary assessment (EMA) and administers brief tests of associative memory, processing speed, and working memory up to 4 times per day over 7 consecutive days. ARC was designed to be administered unsupervised using participants' personal devices in their everyday environments. METHODS: We evaluated the reliability and validity of ARC in a sample of 268 cognitively normal older adults (ages 65-97 years) and 22 individuals with very mild dementia (ages 61-88 years). Participants completed at least one 7-day cycle of ARC testing and conventional cognitive assessments; most also completed cerebrospinal fluid, amyloid and tau positron emission tomography, and structural magnetic resonance imaging studies. RESULTS: First, ARC tasks were reliable as between-person reliability across the 7-day cycle and test-retest reliabilities at 6-month and 1-year follow-ups all exceeded 0.85. Second, ARC demonstrated construct validity as evidenced by correlations with conventional cognitive measures (r = 0.53 between composite scores). Third, ARC measures correlated with AD biomarker burden at baseline to a similar degree as conventional cognitive measures. Finally, the intensive 7-day cycle indicated that ARC was feasible (86.50% approached chose to enroll), well tolerated (80.42% adherence, 4.83% dropout), and was rated favorably by older adult participants. CONCLUSIONS: Overall, the results suggest that ARC is reliable and valid and represents a feasible tool for assessing cognitive changes associated with the earliest stages of AD.

To BYOD or not: Are device latencies important for bring-your-own-device (BYOD) smartphone cognitive testing?

Studies using remote cognitive testing must make a critical decision: whether to allow participants to use their own devices or to provide participants with a study-specific device. Bring-your-own-device (BYOD) studies have several advantages including increased accessibility, potential for larger sample sizes, and reduced participant burden. However, BYOD studies offer little control over device performance characteristics that could potentially influence results. In particular, response times measured by each device not only include the participant's true response time, but also latencies of the device itself. The present study investigated two prominent sources of device latencies that pose significant risks to data quality: device display output latency and touchscreen input latency. We comprehensively tested 26 popular smartphones ranging in price from < $100 to $1000+ running either Android or iOS to determine if hardware and operating system differences led to appreciable device latency variability. To accomplish this, a custom-built device called the Latency and Timing Assessment Robot (LaTARbot) measured device display output and capacitive touchscreen input latencies. We found considerable variability across smartphones in display and touch latencies which, if unaccounted for, could be misattributed as individual or group differences in response times. Specifically, total device (sum of display and touch) latencies ranged from 35 to 140 ms. We offer recommendations to researchers to increase the precision of data collection and analysis in the context of remote BYOD studies.

The effect of context on mind-wandering in younger and older adults.

Older adults report less mind-wandering (MW) during tasks of sustained attention than younger adults. The control failure × current concerns account argues that this is due to age differences in how contexts cue personally relevant task-unrelated thoughts. For older adults, the university laboratory contains few reminders of their current concerns and unfinished goals. For younger adults, however, the university laboratory is more directly tied to their current concerns. Therefore, if the context for triggering current concerns is the critical difference between younger and older adults' reported MW frequencies, then testing the two groups in contexts that equate the salience of self-relevant cues (i.e., their homes) should result in an increase in older but not younger adults' MW rates. The present study directly compared rates of MW and involuntary autobiographical memories (IAMs) in the home versus in the lab for younger and older adults using a within-subjects manipulation of context. Inconsistent with the control failure × current concerns account, no significant reduction in the age-gap in MW was found. Suggesting a lack of cues rather than an abundance of cues elicits MW, participants in both age groups reported more MW in the lab than at home. The number of IAMs recalled did not differ across contexts but was lower in older than younger adults. These findings suggest that a cognitive rather than an environmental mechanism may be behind the reduction in spontaneous cognition in aging.

Pick a PACC: Comparing domain-specific and general cognitive composites in Alzheimer disease research.

OBJECTIVE: We aimed to illustrate how complex cognitive data can be used to create domain-specific and general cognitive composites relevant to Alzheimer disease research. METHOD: Using equipercentile equating, we combined data from the Charles F. and Joanne Knight Alzheimer Disease Research Center that spanned multiple iterations of the Uniform Data Set. Exploratory factor analyses revealed four domain-specific composites representing episodic memory, semantic memory, working memory, and attention/processing speed. The previously defined preclinical Alzheimer disease cognitive composite (PACC) and a novel alternative, the Knight-PACC, were also computed alongside a global composite comprising all available tests. These three composites allowed us to compare the usefulness of domain and general composites in the context of predicting common Alzheimer disease biomarkers. RESULTS: General composites slightly outperformed domain-specific metrics in predicting imaging-derived amyloid, tau, and neurodegeneration burden. Power analyses revealed that the global, Knight-PACC, and attention and processing speed composites would require the smallest sample sizes to detect cognitive change in a clinical trial, while the Alzheimer Disease Cooperative Study-PACC required two to three times as many participants. CONCLUSIONS: Analyses of cognition with the Knight-PACC and our domain-specific composites offer researchers flexibility by providing validated outcome assessments that can equate across test versions to answer a wide range of questions regarding cognitive decline in normal aging and neurodegenerative disease. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Precipitating Mechanisms of Falls in Preclinical Alzheimer's Disease.

Background: Individuals with Alzheimer's disease (AD) are more than twice as likely to incur a serious fall as the general population of older adults. Although AD is commonly associated with cognitive changes, impairments in other clinical measures such as strength or functional mobility (i.e., gait and balance) may precede symptomatic cognitive impairment in preclinical AD and lead to increased fall risk. Objective: To examine mechanisms (i.e., functional mobility, cognition, AD biomarkers) associated with increased falls in cognitively normal older adults. Methods: This 1-year study was part of an ongoing longitudinal cohort study. We examined the relationships among falls, clinical measures of functional mobility and cognition, and neuroimaging AD biomarkers in cognitively normal older adults. We also investigated which domain(s) best predicted fall propensity and severity through multiple regression models. Results: A total of 182 older adults were included (mean age 75 years, 53% female). A total of 227 falls were reported over the year; falls per person ranged from 0-16 with a median of 1. Measures of functional mobility were the best predictors of fall propensity and severity. Cognition and AD biomarkers were associated with each other but not with the fall outcome measures. Conclusion: These results suggest that, although subtle changes in cognition may be more closely associated with AD neuropathology, functional mobility indicators better predict falls in cognitively normal older adults. This study adds to our understanding of the mechanisms underlying falls in older adults and could lead to the development of targeted fall prevention strategies.

The effects of wakeful rest on memory consolidation in an online memory study.

Memory consolidation is the process in which memory traces are strengthened over time for later retrieval. Although some theories hold that consolidation can only occur during sleep, accumulating evidence suggests that brief periods of wakeful rest may also facilitate consolidation. Interestingly, however, Varma and colleagues reported that a demanding 2-back task following encoding produced a similar performance to a wakeful reset condition. We tested whether participants' recall would be best following a wakeful rest condition as compared to other distractor conditions, consistent with the extant wakeful rest literature, or whether we would replicate the finding by Varma and colleagues such that participants' memory benefitted from both a rest and a 2-back task following encoding. Across two experiments, we used similar (Experiment 1) and the same (Experiment 2) encoding material as used the one by Varma and colleagues, employed a wakeful rest condition adapted for online testing, and compared participants' recall across post-encoding conditions. In the first experiment, we used a between-subjects design and compared participants' cued recall performance following a period of wakeful rest, a 2-back task, or a rest + sounds condition. The second experiment more closely replicated the experimental design used by Varma and colleagues using a within-subjects manipulation. Ultimately, our findings more consistently aligned with the canonical wakeful rest finding, such that recall was better following the rest condition than all other post-encoding conditions. These results support the notion that wakeful rest may allow for consolidation by protecting recently encoded information from interference, thereby improving memory performance.

Targeted memory reactivation and consolidation-like processes during mind-wandering in younger and older adults.

Mind-wandering (MW) is a universal cognitive process that is estimated to comprise ~30% of our everyday thoughts. Despite its prevalence, the functional utility of MW remains a scientific blind spot. The present study sought to investigate whether MW serves a functional role in cognition. Specifically, we investigated whether MW contributes to memory consolidation-like processes, and if age differences in the ability to reactivate episodic memories during MW may contribute to age-related declines in episodic memory. Younger and older adults encoded paired associates, received targeted reactivation cues during an interval filled with a task that promotes MW, and were tested on their memory for the cued and uncued stimuli from the initial encoding task. Thought probes were presented during the retention (MW) interval to assess participants' thought contents. Across four experiments, we compared the effect of different cue modalities (i.e., auditory, visual) on cued recall performance, and examined both correct retrieval RTs as well as accuracy. Across experiments, there was evidence that stimuli that were cued during the MW task were correctly retrieved more quickly than uncued stimuli and that this effect was more robust for younger adults than older adults. Additionally, the more MW a participant reported during the retention interval, the stronger the cuing effect they produced during retrieval. The results from these experiments are interpreted within a retrieval facilitation framework wherein cues serve to reactivate the earlier traces during MW, and this reactivation benefits retrieval speed for cued items compared with uncued items. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

What Can Brinley Plots Tell Us About Cognitive Aging? Exploring Simulated Data and Modified Brinley Plots.

Cognitive aging researchers have been challenged with demonstrating age-related effects above and beyond global slowing ever since Cerella raised this issue in 1990. As the literature has made clear, this has indeed proved to be a difficult task and continues to plague the field. One way that researchers have attempted to test for disproportionate age differences across task conditions is by using Brinley plots, or plotting the mean response latencies of older adults against the mean latencies for younger adults. The simplicity and large proportion of variance accounted for by these models has led to the widespread use of Brinley plots over the years. However, as systematically tested here through eight cases of simulated data, it is clear that the Brinley technique is not well suited to either identify or display the underlying structure of datasets examining age-related differences in attentional control. Some of the problems with conventional Brinley plots can be resolved by using a modified Brinley plot that includes study-specific slopes linking trial types and a no-age-difference reference line. Multilevel models find all of the relevant effects, especially if applied to trial-level data, and have the advantage of incorporating study-level moderators that might account for slope heterogeneity. Ultimately, we encourage fellow cognitive aging researchers to access the code and data for this project on OSF (https://osf.io/zxus8/) and employ the use of multilevel models over Brinley plots.

A multimodal analysis of sustained attention in younger and older adults.

Age-related cognitive decline has been attributed to processing speed differences, as well as differences in executive control and response inhibition. However, recent research has shown that healthy older adults have intact, if not superior, sustained attention abilities compared to younger adults. The present study used a combination of reaction time (RT), thought probes, and pupillometry to measure sustained attention in samples of younger and older adults. The RT data revealed that, while slightly slower overall, older adults sustained their attention to the task better than younger adults, and did not show a vigilance decrement. Older adults also reported fewer instances of task-unrelated thoughts and reported feeling more motivated and alert than younger adults, despite finding the task more demanding. Additionally, older adults showed larger, albeit later-peaking, task-evoked pupillary responses (TEPRs), corroborating the behavioral and self-report data. Finally, older adults did not show a shallowing of TEPRs across time, corroborating the finding that their RTs also did not change across time. The present findings are interpreted in light of processing speed theory, resource-depletion theories of vigilance, and recent neurological theories of cognitive aging. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Bridging the Technological Divide: Stigmas and Challenges With Technology in Digital Brain Health Studies of Older Adults.

The COVID-19 pandemic has increased adoption of remote assessments in clinical research. However, longstanding stereotypes persist regarding older adults' technology familiarity and their willingness to participate in technology-enabled remote studies. We examined the validity of these stereotypes using a novel technology familiarity assessment (n = 342) and with a critical evaluation of participation factors from an intensive smartphone study of cognition in older adults (n = 445). The technology assessment revealed that older age was strongly associated with less technology familiarity, less frequent engagement with technology, and higher difficulty ratings. Despite this, the majority (86.5%) of older adults elected to participate in the smartphone study and showed exceptional adherence (85.7%). Furthermore, among those enrolled, neither technology familiarity, knowledge, perceived difficulty, nor gender, race, or education were associated with adherence. These results suggest that while older adults remain significantly less familiar with technology than younger generations, with thoughtful study planning that emphasizes participant support and user-centered design, they are willing and capable participants in technology-enabled studies. And once enrolled, they are remarkably adherent.

Dispositional factors account for age differences in self-reported mind-wandering.

The present study investigated the contribution of dispositional factors in accounting for the perplexing negative relationship between aging and mind-wandering (MW). First, we sought to examine whether experimentally manipulating participants' motivation during a modified Sustained Attention to Response Task (SART) would modulate sustained attention performance and MW reports for younger and older adults. Results indicated that a performance-based motivational incentive influenced self-reported motivation and objective measures of sustained attention performance for younger, but not older, adults as compared to a control block. However, the motivation manipulation did not significantly modulate either younger or older adults' MW reports. Second, we tested the unique contributions of conscientiousness, interest, and motivation in predicting state-level, trait-level, and SART MW reports along with a composite measure of all three predictors. The results from a series of mediation and regression analyses indicated (a) that conscientiousness and interest fully accounted for the relationship between age and four different self-reported MW estimates and (b) that self-reported motivation did not account for any unique variance in predicting MW reports above and beyond age. The dispositional factors also accounted for the observed differences in No-Go accuracy but did not fully account for the age differences in the coefficient of variation. Discussion focuses on distinctions between self-report and objective measures of MW and more general implications of considering dispositional factors in cognitive aging research. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Re-examining age differences in the Stroop effect: The importance of the trees in the forest (plot).

Despite several meta-analyses suggesting that age differences in attentional control are "greatly exaggerated," there have been multiple reports of disproportionate age differences in the Stroop effect. The Stroop task is widely accepted as the gold standard for assessing attentional control and has been critical in comparisons across development and in studies of neuropsychological patient groups. However, accounting for group differences in processing speed is a notorious challenge in interpreting reaction time (RT) data. Within the aging literature, prior meta-analyses have relied on Brinley and State-Trace techniques to account for overall processing speed differences in evaluating the effects of within-participant manipulations. Such analyses are based on mean performance per group per study and have been criticized as potentially being insensitive to within-participant manipulations. In order to further examine possible age differences in Stroop performance, we amassed a dataset from 33 different computerized, color-naming Stroop task studies with available trial-level data from 2,896 participants. We conducted meta-regression analyses on a wide set of dependent measures that control for general slowing, tested for publication bias, and examined four potential methodological moderators. We also conducted linear mixed-effect modeling allowing the intercept to vary randomly for each participant, thereby accounting for individual differences in processing speed. All analyses, with the exception of the Brinley and State-Trace techniques, produced clear evidence supporting a disproportionate age difference in the Stroop effect above and beyond the effects of general slowing. Discussion highlights the importance of trial-level data in accounting for group differences in processing speed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Is comprehensiveness critical? Comparing short and long format cognitive assessments in preclinical Alzheimer disease.

BACKGROUND: Comprehensive testing of cognitive functioning is standard practice in studies of Alzheimer disease (AD). Short-form tests like the Montreal Cognitive Assessment (MoCA) use a "sampling" of measures, administering key items in a shortened format to efficiently assess cognition while reducing time requirements, participant burden, and administrative costs. We compared the MoCA to a commonly used long-form cognitive battery in predicting AD symptom onset and sensitivity to AD neuroimaging biomarkers. METHODS: Survival, area under the receiver operating characteristic (ROC) curve (AUC), and multiple regression analyses compared the MoCA and long-form measures in predicting time to symptom onset in cognitively normal older adults (n = 6230) from the National Alzheimer's Coordinating Center (NACC) cohort who had, on average, 2.3 ± 1.2 annual assessments. Multiple regression models in a separate sample (n = 416) from the Charles F. and Joanne Knight Alzheimer Disease Research Center (Knight ADRC) compared the sensitivity of the MoCA and long-form measures to neuroimaging biomarkers including amyloid PET, tau PET, and cortical thickness. RESULTS: Hazard ratios suggested that both the MoCA and the long-form measures are similarly and modestly efficacious in predicting symptomatic conversion, although model comparison analyses indicated that the long-form measures slightly outperformed the MoCA (HRs > 1.57). AUC analyses indicated no difference between the measures in predicting conversion (DeLong's test, Z = 1.48, p = 0.13). Sensitivity to AD neuroimaging biomarkers was similar for the two measures though there were only modest associations with tau PET (rs = - 0.13, ps < 0.02) and cortical thickness in cognitively normal participants (rs = 0.15-0.16, ps < 0.007). CONCLUSIONS: Both test formats showed weak associations with symptom onset, AUC analyses indicated low diagnostic accuracy, and biomarker correlations were modest in cognitively normal participants. Alternative assessment approaches are needed to improve how clinicians and researchers monitor cognitive changes and disease progression prior to symptom onset.

The consequences of processing goal-irrelevant information during the Stroop task.

Recent evidence indicates that older adults' decreased ability to inhibit irrelevant information may lead to increased processing and greater memory for distractor information compared with younger adults. The present experiments examine the generality of this finding in a series of Stroop studies. In Experiment 1, participants studied a list of words then received a Stroop color naming task, with to-be-remembered words embedded within the Stroop task. Although there was evidence of a disproportionate age-related Stroop effect, there was no evidence of an age difference in episodic recognition memory for words from the Stroop task. Experiment 2 extended this paradigm to a more implicit demasking task. Again, there was evidence of an age-related disproportionate Stroop effect, however, there were no differences in memory for unattended words in demasking performance. Experiment 3 was a direct replication of a previous study which reported age differences in the influence of unattended words, via implicit priming in a general knowledge test. The results did not replicate the original study such that younger adults showed slightly more priming from distractors than older adults. The results provide converging evidence that although older adults have more difficulty inhibiting irrelevant information in the Stroop task, distractor information does not seem to disproportionately influence later memory for older adults compared with younger adults. These studies suggest that it is critical to consider the locus of memory encoding in distractor tasks to better understand the relationship between inhibitory processes during the distractor task and later memory performance. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Age differences in cross-task bleeding.

The present study investigated age-related differences in the ability to constrain attention to the current task, without contamination (bleeding) from an upcoming decision. Each experiment included two blocks of trials. During Block 1, participants initially incidentally encoded a list of high- and low-frequency words, after which they pronounced aloud the studied words intermixed with a new set of words during a test phase. Block 2 was identical to Block 1 with the exception that after pronouncing each word aloud, participants made an additional decision (episodic recognition decision in Experiments 1 and 2 and animacy decision in Experiment 3). In the first two experiments, older adults showed disproportionate slowing in their response times to pronounce the words when they additionally had to make a recognition judgment afterward (Block 2) compared to when they only pronounced the words aloud (Block 1). Importantly, the difference between high-frequency and low-frequency words (the word frequency effect) was disproportionately attenuated for older adults in Block 2 compared to Block 1 and compared to younger adults. These results suggest that older adults experience greater cross-task bleeding than younger adults because word frequency has opposing effects in pronunciation and recognition tasks. As predicted, this age modulation of the word frequency effect in pronunciation performance was not replicated in Experiment 3 when participants made an animacy judgment, wherein word frequency effects act in concert with those of the pronunciation task. Discussion focuses on age-related differences in the ability to constrain attention to a current task. (PsycInfo Database Record (c) 2020 APA, all rights reserved).