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BackgroundCognitive reserve may protect against cognitive decline. However, its effect on physiological measures of cognitive workload in adults with cognitive impairments is unclear.ObjectiveThe aim was to determine the association between cognitive reserve and physiological measures of cognitive workload in older adults with and without cognitive impairments.Methods29 older adults with cognitive impairment (age: 75±6, 11 (38%) women, MOCA scores 20±7) and 19 with normal cognition (age: 74±6; 11 (58%) women; MOCA 28±2) completed a working memory test of increasing task demand (0-, 1-, 2-back). Cognitive workload was indexed using amplitude and latency of the P3 event-related potential (ERP) at electrode sites Fz, Cz, and Pz, and changes in pupillary size, converted to an index of cognitive activity (ICA). The Cognitive Reserve Index questionnaire (CRIq) evaluated Education, Work Activity, and Leisure Time as a proxy of cognitive reserve.ResultsHigher CRIq total scores were associated with larger P3 ERP amplitude (p=0.048), independent of cognitive status (p=0.80), task demand (p=0.003), and electrode site (pConclusionCognitive reserve affects cognitive workload and neural efficiency, regardless of cognitive status. Future longitudinal studies should investigate the causal relationship between cognitive reserve and physiological processes of neural efficiency across cognitive aging.

Background The growing societal and economic impact of Alzheimer’s disease (AD) is further compounded by the present lack of disease-modifying interventions. Non-pharmacological intervention approaches, such as exercise, have the potential to be powerful approaches to improve or mitigate the symptoms of AD without added side effects or financial burden associated with drug therapies. Various forms and regiments of exercise (i.e., strength, aerobic, multicomponent) have been reported in the literature; however, conflicting evidence obscures clear interpretation of the value and impact of exercise as an intervention for older adults with AD. The primary objective of this review will be to evaluate the effects of exercise interventions for older adults with AD. In addition, this review will evaluate the evidence quality and synthesize the exercise training prescriptions for proper clinical practice guidelines and recommendations. Methods This systematic review and meta-analysis will be carried out by an interdisciplinary collective representing clinical and research stakeholders with diverse expertise related to neurodegenerative diseases and rehabilitation medicine. Literature sources will include the following: Embase, PsychINFO, OVID Medline, and Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily. Inclusion criteria are participants with late onset AD and structured exercise interventions with prescribed duration, frequency, and intensity. The primary outcome of this study will center on improved or sustained cognitive functioning. Secondary outcomes will include institutionalization-related outcomes, ability in activities of daily living, mood and emotional well-being, quality of life, morbidity, and mortality. Analysis procedures to include measurement of bias, data synthesis, sensitivity analysis, and assessment of heterogeneity are described in this protocol. Discussion This review is anticipated to yield clinically meaningful insight on the specific value of exercise for older adults with AD. Improved understanding of diverse exercise intervention approaches and their specific impact on various health- and function-related outcomes is expected to guide clinicians to more frequently and accurately prescribe meaningful interventions for those affected by AD. Systematic review registration PROSPERO CRD42020175016.

Background: Growing evidence links beta-amyloid (Aβ) and neuronal hyperexcitability in preclinical mouse models of Alzheimer’s disease (AD). The aim of this study was to compare neuronal excitability between cognitively normal amyloid positive (CNAβ+) and those without elevated amyloid (CNAβ-) older adults. We hypothesized CNAβ+ participants would show hyperexcitability, indexed by greater peak P3 event-related potential peak amplitude, shorter peak latency, and changes in event-related power, compared to CNAβ-.Methods: CNAβ+ participants (n = 17, age: 73 ± 5, 11 women, MOCA scores 26 ± 2) and 17 CNAβ- participants group-matched for age, sex, and MOCA completed the a working memory task (n-back with n = 0, 1, 2) test while wearing a 256-channel EEG net. P3 peak amplitude and latency of the nontarget, target and task difference (nontarget – target), and event-related power, extracted from Fz (main outcome), Cz, and Pz were compared between groups using linear mixed models. Mean Aβ standard uptake value ratios (SUVR) were correlated with P3 amplitude and latency using Pearson r.Results: P3 peak amplitude of the task difference (p = 0.048) and P3 peak latency of non-targets trials (p = 0.006) at Fz differed between groups. Similarly, power was lower in the delta band (p = 0.04) for nontargets at Fz in CNAβ+ participants. CNAβ+ participants also demonstrated higher theta and alpha power in channels at Cz and Pz, but no changes in P3 ERP. Strong correlations were found between mean Aβ SUVR and latency of the 1-back (r = -0.69; p = 0.003) and 2-back (r = -0.69; p = 0.004) of the task difference at channel Fz in the CNAβ+ group.Conclusions: Our pilot data suggests that elevated amyloid in cognitive normal older adults is associated with hyperexcitability in P3 ERP. Further research is warranted to determine the validity of ERP in predicting clinical, neurobiological, and functional manifestations of AD.

Background Although growing evidence links beta-amyloid (Aβ) and neuronal hyperexcitability in preclinical mouse models of Alzheimer’s disease (AD), a similar association in humans is yet to be established. The first aim of the study was to determine the association between elevated Aβ (Aβ+) and cognitive processes measured by the P3 event-related potential (ERP) in cognitively normal (CN) older adults. The second aim was to compare the event-related power between CNAβ+ and CNAβ−. Methods Seventeen CNAβ+ participants (age: 73 ± 5, 11 females, Montreal Cognitive Assessment [MoCA] score 26 ± 2) and 17 CNAβ- participants group-matched for age, sex, and MOCA completed a working memory task (n-back with n = 0, 1, 2) test while wearing a 256-channel electro-encephalography net. P3 peak amplitude and latency of the target, nontarget and task difference effect (nontarget−target), and event-related power in the delta, theta, alpha, and beta bands, extracted from Fz, Cz, and Pz, were compared between groups using linear mixed models. P3 amplitude of the task difference effect at Fz and event-related power in the delta band were considered main outcomes. Correlations of mean Aβ standard uptake value ratios (SUVR) using positron emission tomography with P3 amplitude and latency of the task difference effect were analyzed using Pearson Correlation Coefficient r. Results The P3 peak amplitude of the task difference effect at Fz was lower in the CNAβ+ group (P = 0.048). Similarly, power was lower in the delta band for nontargets at Fz in the CNAβ+ participants (P = 0.04). The CNAβ+ participants also demonstrated higher theta and alpha power in channels at Cz and Pz, but no changes in P3 ERP. Strong correlations were found between the mean Aβ SUVR and the latency of the 1-back (r = − 0.69; P = 0.003) and 2-back (r = − 0.69; P = 0.004) of the task difference effect at channel Fz in the CNAβ+ group. Conclusions Our data suggest that the elevated amyloid in cognitively normal older adults is associated with neuronal hyperexcitability. The decreased P3 task difference likely reflects early impairments in working memory processes. Further research is warranted to determine the validity of ERP in predicting clinical, neurobiological, and functional manifestations of AD.

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Cognitive workload (mental effort) is a measure of attention allocation to a task, which can be administered through self-report or physiological measures. Cognitive workload is increasingly recognized as an important determinant of performance in cognitive tests and daily life activities. However, the reliability and validity of these measures have not been established in older adults with a wide range of cognitive ability. The aim of this study was to establish the test-retest reliability of the NASA-Task Load Index (NASA-TLX) and Index of Cognitive Activity (ICA), extracted from pupillary size. The convergent validity of these measures against event-related potentials (ERPs) was also investigated. A total of 38 individuals with scores on the Montreal Cognitive Assessment ranging between 17 and 30 completed a working memory test (n-back) with three levels of difficulty at baseline and two-week follow-up. Intraclass correlation coefficients (ICC) values of the NASA-TLX ranged between 0.71 and 0.81, demonstrating good to excellent reliability. Mean ICA scores showed fair to good reliability, with ICC’s ranging between 0.56 and 0.73. Mean ICA and NASA-TLX scores showed significant and moderate correlations (Pearson r range between 0.30 and 0.33) with P3 ERP at the midline channels. We conclude that ICC and NASA-TLX are reliable measures of cognitive workload in older adults. Further research is needed in dissecting the subjective and objective constructs of cognitive workload.

BACKGROUNDAdvances in medical technology produce highly complex datasets in neurorehabilitation clinics and research laboratories. Artificial neural networks (ANNs) have been utilized to analyze big and complex datasets in various fields, but the use of ANNs in neurorehabilitation is limited. OBJECTIVE: To explore the current use of ANNs in neurorehabilitation. METHODS: PubMed, CINAHL, and Web of Science were used for literature search. Studies in the scoping review (1) utilized ANNs, (2) examined populations with neurological conditions, and (3) focused rehabilitation outcomes. The initial search identified 1,136 articles. A total of 19 articles were included. RESULTS: ANNs were used for prediction of functional outcomes and mortality (n = 11) and classification of motor symptoms and cognitive status (n = 8). Most ANN-based models outperformed regression or other machine learning models (n = 11) and showed accurate performance (n = 6; no comparison with other models) in predicting clinical outcomes and accurately classifying different neurological impairments.CONCLUSIONSThis scoping review provides encouraging evidence to use ANNs for clinical decision-making of complex datasets in neurorehabilitation. However, more research is needed to establish the clinical utility of ANNs in diagnosing, monitoring, and rehabilitation of individuals with neurological conditions.

Research Objectives To examine the impact of task difficulty on driving performance in preclinical Alzheimer's Disease (AD). We hypothesized that performance on driving simulator tasks will discriminate between drivers with preclinical AD and controls. Design A cross-sectional, observational study. Setting University of Kansas Medical Center. Participants Twenty participants (14 women) were included: 10 with preclinical AD [age 73.6±5] and 10 controls without preclinical AD [age 74.9±6.5], matched for age, sex, and cognitive status. Interventions Not applicable. Main Outcome Measures Participants completed a cognitively demanding car following task with and without a dual task in a semi-immersive virtual reality driving simulator. The 2-back test was used as the dual-task test. Standard deviation of lateral position (SDLP) and speed (SDS) were the primary outcomes of lateral and longitudinal vehicle control, respectively. Two-way ANOVA were employed to investigate main effects of task complexity (single versus dual task) and group (preclinical AD vs controls). Results Both groups showed significant increase in SDLP when engaged in a dual task (p = 0.001). SDLP increased from (mean ± SD in feet) 0.50 ± 0.30 in single task to 0.70 ±0.40 in dual-task conditions in preclinical AD group. SDLP increased from 0.55 ±0.33 in single task to 0.88 ±0.34 in dual-task conditions in controls. No other within or between group effects were observed. Conclusions While the measure of lateral vehicle control (SDLP) showed to be sensitive to task complexity, the measure of speed (SDS) showed less sensitivity. Neither measure discriminated between drivers with preclinical AD and controls. A better powered study with more participants may show more meaningful findings. Author(s) Disclosures Any conflict of interest will be disclosed by coauthors. I, Pedram Ahmadnezhad (author) do not have any conflicts of interest.

Cognitive workload is increasingly recognized as an important determinant of performance in cognitive tests and daily life activities. Cognitive workload is a measure of physical and mental effort allocation to a task, which can be determined through self-report or physiological measures. However, the reliability and validity of these measures have not been established in older adults with a wide range of cognitive ability. The aim of this study was to establish the test&ndash, retest reliability of the National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Index of Cognitive Activity (ICA), extracted from pupillary size. The convergent validity of these measures against event-related potentials (ERPs) was also investigated. A total of 38 individuals with scores on the Montreal Cognitive Assessment ranging between 17 and 30 completed a working memory test (n-back) with three levels of difficulty at baseline and at a two-week follow-up. The intraclass correlation coefficients (ICC) values of the NASA-TLX ranged between 0.71 and 0.81, demonstrating good to excellent reliability. The mean ICA scores showed fair to good reliability, with ICCs ranging between 0.56 and 0.73. The mean ICA and NASA-TLX scores showed significant and moderate correlations (Pearson&rsquo, s r ranging between 0.30 and 0.33) with the third positive peak of the ERP at the midline channels. We conclude that ICA and NASA-TLX are reliable measures of cognitive workload in older adults. Further research is needed in dissecting the subjective and objective constructs of cognitive workload.

BACKGROUND: Using in-vehicle audio technologies such as audio systems and voice messages is regarded as a common secondary task. Such tasks, known as the sources of non-visual distraction, affect the driving performance. Given the elderly drivers' cognitive limitations, driving can be even more challenging to drivers. The current study examined how listening to economic news, as a cognitively demanding secondary task, affects elderly subjects' driving performance and whether their comprehension accuracy is associated with these effects. METHODS: Participants of the study (N=22) drove in a real condition with and without listening to economic news. Measurements included driving performance (speed control, forward crash risk, and lateral lane position) and task performance (comprehension accuracy). RESULTS: The mean driving speed, duration of driving in unsafe zones and numbers of overtaking decreased significantly when drivers were engaged in the dual-task condition. Moreover, the cognitive secondary task led to a higher speed variability. Our results demonstrate that there was not a significant relationship between the lane changes and the activity of listening to economic news. However, a meaningful difference was observed between general comprehension and deep comprehension on the one hand and driving performance on the other. Another aspect of our study concerning the drivers' ages and their comprehension revealed a significant relationship between age above 75 and comprehension level. Drivers aging 75 and older showed a lower level of deep comprehension. CONCLUSION: Our study demonstrates that elderly drivers compensated driving performance with safety margin adoption while they were cognitively engaged. In this condition, however, maintaining speed proved more demanding for drivers aging 75 and older.Copyright © 2016 Elsevier Ltd. All rights reserved. Language: en