Madison A. Niermeyer

Motor sequencing in older adulthood: relationships with executive functioning and effects of complexity

Abstract Objective: Older adults’ motor sequencing performance is more reliant on executive functioning (EF) and more susceptible to complexity than that of younger adults. This study examined for which aspects of motor sequencing performance these relationships hold. Methods: Fifty-seven younger and 90 non-demented, community-dwelling, older adults completed selected subtests from the Delis–Kaplan Executive Function System as indices of EF and component processes (CP; graphomotor speed; visual scanning; etc.), as well as a computerized motor sequencing task (Push Turn Taptap task; PTT). The PTT requires participants to perform motor sequences that become progressively more complex across the task’s four blocks, and is designed to assess action planning, action learning, and motor control speed and accuracy. Results: Hierarchical regressions using each discrete aspect of performance as the dependent variable revealed that action planning is the only aspect of motor sequencing that is uniquely related to EF (beyond the CP composite) for both age groups. Action learning and motor control accuracy are uniquely associated with EF for older adults only, and only if the sequences are complex. Component processes do not fully account for the unique relationships between motor sequencing and EF in older adults. Conclusions: These results clarify prior findings by showing (a) more aspects of motor sequencing relate to EF for older compared to younger adults and (b) for these unique relationships, EF is only related to action during the generation of sequences that are complex. These findings further our understanding of how aging shapes the links between EF and motor actions, and can be used in evidence-based and theoretically driven intervention programs that promote healthy aging.

Neurocognitive and neurophysiological correlates of motor planning during familiar and novel contexts.

OBJECTIVE Research suggests that behavioral indices of motor planning (i.e., latencies that precede motor output) (a) relate to processing speed (PS) and executive functioning (EF), but not working memory (WM), and (b) deteriorate in novel contexts. It is not clear whether an electrophysiological index of motor planning (i.e., movement-related cortical potentials; MRCPs) also relates to PS and EF, and whether it deteriorates in novel contexts. This study sought to clarify associations among these variables while manipulating contextual novelty. METHOD Forty healthy adults completed standardized measures of PS, EF, and WM. Participants performed highly familiar motor sequences in familiar versus novel contexts during EEG recording, while motor planning latencies and peak MRCPs were obtained. Hierarchical regressions assessed the relative contributions of PS, EF, and WM to motor planning latencies and MRCPs. RESULTS Novel contexts elicited longer planning latencies (gav = 1.96) and reduced MRCPs (gav = .24) compared to familiar contexts. PS predicted planning times in both familiar (R² = .12) and novel contexts (R² = .15), while EF contributed additional variance during novel contexts only (R² Change = .10). EF was the sole predictor of MRCPs in both familiar (R² = .12) and novel contexts (R² = .18). WM did not predict planning latencies or MRCPs. CONCLUSIONS Contextual novelty alone can decrease performance and neural activation during complex sequencing. The general link between preparatory activation and EF suggests that capacity limitations drive novelty effects, and implies a common substrate underlying motor planning and higher-order behavioral control.

Reported Expressive Suppression in Daily Life Is Associated with Slower Action Planning.

Objectives Growing evidence demonstrates that (a) executive functioning (EF) becomes deleteriously affected by engagement in the emotion regulation strategy known as expressive suppression and (b) EF shows considerable functional and neuroanatomical overlap with motor output. The current study aimed to bridge these two literatures by examining the relationships between naturally occurring expressive suppression and several different aspects of motor output, including action planning, action learning, and motor-control speed and accuracy. In addition, we investigated whether any identified relationships could be explained by EF. Methods Fifty-one healthy young adults completed selected subtests from the Delis-Kaplan Executive Function System as indices of EF, a self-report measure of expressive suppression, and a computerized motor sequencing task (Push Turn Taptap task; PTT) designed to assess action planning, action learning, and motor control speed and accuracy. Results Hierarchical regressions using each aspect of PTT performance as the dependent variable revealed that higher than usual self-reported expressive suppression on the day of testing (relative to the 2 weeks preceding testing) was associated with longer action-planning latencies. This relationship was fully explained by EF. No other PTT variables related to expressive suppression on the day of testing. Conclusions These results suggest that increased expressive suppression in daily life is associated with slower action planning, an aspect of motor output that is reliant on EF, highlighting the importance of factors that lead to intra-individual fluctuations in EF and motor performance. (JINS, 2016, 22, 671-681).

Working memory performance inversely predicts spontaneous delta and theta-band scaling relations

Electrophysiological studies have strongly implicated theta-band activity in human working memory processes. Concurrently, work on spontaneous, non-task-related oscillations has revealed the presence of long-range temporal correlations (LRTCs) within sub-bands of the ongoing EEG, and has begun to demonstrate their functional significance. However, few studies have yet assessed the relation of LRTCs (also called scaling relations) to individual differences in cognitive abilities. The present study addressed the intersection of these two literatures by investigating the relation of narrow-band EEG scaling relations to individual differences in working memory ability, with a particular focus on the theta band. Fifty-four healthy adults completed standardized assessments of working memory and separate recordings of their spontaneous, non-task-related EEG. Scaling relations were quantified in each of the five classical EEG frequency bands via the estimation of the Hurst exponent obtained from detrended fluctuation analysis. A multilevel modeling framework was used to characterize the relation of working memory performance to scaling relations as a function of general scalp location in Cartesian space. Overall, results indicated an inverse relationship between both delta and theta scaling relations and working memory ability, which was most prominent at posterior sensors, and was independent of either spatial or individual variability in band-specific power. These findings add to the growing literature demonstrating the relevance of neural LRTCs for understanding brain functioning, and support a construct- and state-dependent view of their functional implications.

The Impacts of Sexual Arousal and Its Suppression on Executive Functioning

Suppression of certain types of reflexive emotional responses is thought to temporarily deplete executive functions (EF), as evidenced by poorer performance on measures of EF, but does not deplete other, lower-order cognitive processes. This study examined whether similar decrements in performance on EF tests would occur following suppression of sexual arousal. A sample of 44 male college students underwent baseline cognitive assessment (EF and lower-order cognitive processes), followed by experimental manipulation consisting of exposure to sexually explicit audiovisual stimuli. Sexual arousal was monitored using penile plethysmography. In this study, 21 participants were assigned to a suppression condition and were instructed to suppress sexual arousal during the video, while 23 were assigned to an arousal condition and were instructed to allow themselves to become aroused. Following experimental manipulation, cognition was reassessed. Unexpectedly, results showed EF decrements in the arousal group but not in the suppression group. As expected, only EF was affected by experimental manipulation, with no group differences in lower-order cognitive processes. Thus, the findings suggest that sexual arousal is associated with temporary decrements in EF performance, at least among young, primarily White, male college students. The results contribute to understanding why sexually charged situations are sometimes associated with poor decisions or unsafe/reckless sexual practices.

Greater naturally occurring expressive suppression is associated with poorer executive functioning and motor-sequence learning among older adults

ABSTRACT Objectives: Unusually high engagement in expressive suppression (i.e., purposeful regulation of overt affect) has been associated with poorer performance on executive functioning (EF) and motor-sequence learning tasks. As such, expressive suppression represents one possible source of fluctuations in executive test performance. However, the relationship between expressive suppression and EF and motor performance has not yet been examined in older adults, who are more prone to EF and motor fluctuations than are younger adults. The purpose of this study was to test whether greater self-reported, naturally occurring expressive suppression is related to poorer EF performance and motor-sequence learning in older adults. Method: One hundred and ten community-dwelling older adults completed a self-report measure of expressive suppression, a battery of EF tests, and a computer-based measure of motor-sequence learning. Results: As expected, higher self-reported burden of expressive suppression in the 24 hours prior to testing was related to poorer performance on EF tests and on multiple aspects of motor-sequence learning (action planning latencies and sequencing errors) even after accounting for age, depressive symptoms, and component processes (e.g., processing speed). Conclusions: The current results suggest that naturally occurring expressive suppression depletes EF, which builds on previous findings from experimental studies that show that expressive suppression leads to reduced EF performance. Furthermore, this effect can be captured using self-report methods. These findings highlight expressive suppression as one source of intraindividual fluctuations in executive and motor functioning, which likely place older adults at risk for both functional and motor lapses (e.g., medication mistakes, falls).

Assessment of Executive Functions in Clinical Settings

Abstract Executive Functioning (EF) is a complex, multifaceted construct consisting of Executive Cognitive Functions, Response Selection, Initiation/Maintenance, Meta-tasking, and Social Cognition (Suchy, Y. (2015). Executive functioning: A comprehensive guide for clinical practice. New York, NY: Oxford University Press). There are many challenges associated with standardized tests of EF, including low reliabilities, test impurity, and a failure of any one test of EF to capture the entire EF construct. To address these, we recommend that clinicians (1) use multiple tests of EF in a given battery and (2) seek out newer instruments that tap into EF subdomains that are often omitted (i.e., meta-tasking and social cognition). When assessing EF, the purpose of assessment also needs to be considered: (1) for diagnostic decision-making, assessment of decline in EF (based on record review, interviews, behavioral observations, and comparisons of test results to demographically corrected norms) is key. Overinterpreting isolated impaired scores should be avoided. (2) For decisions about daily functioning, the following tentative conclusions can be drawn: If EF is moderately to severely impaired relative to population-based norms, functional limitations are likely and if a patient exhibits much variability on tests within a relatively normal profile, risk for intermittent functional lapses in daily life exists.

Exaggerated reaction to novelty as a predictor of incipient cognitive decline among community-dwelling older adults

ABSTRACT Objective: The ability to detect covert markers of incipient cognitive decline among older adults before cognitive decline becomes overtly evident on traditional cognitive tests represents an important topic of research. Exaggerated reactions to novelty, reflected in novelty-induced increases in action planning latencies (“novelty effect”; NE) and low openness to experience (openness), have been previously associated with incipient cognitive decline among older adults who appeared cognitively normal at baseline. The purposes of the present study were to extend prior research on the utility of these markers by examining whether (a) NE and openness each predict cognitive change uniquely, and (b) whether these indices predict cognitive change above and beyond measures of memory, executive functions, processing speed/efficiency, premorbid IQ, and depressive symptoms. Method: Sixty-one cognitively normal community-dwelling older adults were administered a battery of tests assessing the relevant constructs at baseline and one-year follow up. Changes in cognitive status were assessed using the Demetia Rating Scale, 2nd Edition, NE was assessed using the Push–Turn–Taptap task (an electronic motor sequence learning task), and openness using the NEO Personality Inventory–Revised. The Test of Premorbid Functioning, and subtests from Repeatable Battery for the Assessment of Neuropsychological Status, Delis–Kaplan Executive Function System, and Wechsler Adult Intelligence Scale, 4th Edition, were used for additional assessment of baseline cognition. Depressive symptoms were assessed using the Geriatric Depression Scale. Results: Results confirmed our hypothesis that both NE and openness contribute to prediction of cognitive change beyond baseline cognition and depressive symptoms, but none of the covariates (i.e., depression, executive functions, processing efficiency, or memory) themselves contributed to the model. NE and openness each contributed unique variance and were independent of each other. Conclusions: Openness and NE have the potential to provide evidence-based methods for estimating risk of future cognitive change in persons with currently normal standardized test scores.

Assessment of Executive Functions in Research

Assessment of executive functions (EF) for research purposes can take on several different forms, relying on clinical measures of EF, experimental tasks, or self- and informant-reports. Each approach is characterized by a different set of advantages and disadvantages. Researchers need to carefully consider which of these approaches best fits their research question and study design. Additionally, researchers need to make sure that they select tests that are appropriate for the population they use in their research, taking care to avoid floor or ceiling effects. When relying on clinical measures, researches are not only encouraged to rely on norms to help them interpret results but also cautioned to become familiar with the normative samples and normative structures of different tests, so as to ensure comparability across standard scores. A number of psychometric issues also need to be considered, including reliabilities, practice effects, and the contributions of lower order component processes to EF test performance. Lastly, generalization of factor analytic findings to other populations or to the EF construct more globally is discouraged.

Cognitive and gait decrements among non-demented older adults with Type 2 diabetes or hypertension: a systematic review

Abstract Objective: Older adults with Type 2 diabetes (DM2) and hypertension (HTN) often experience cognitive weaknesses. Growing evidence suggests that such weaknesses place patients at risk for gait disturbance and falls. The current systematic review evaluated (a) the impact of DM2 and HTN on cognition and gait and (b) the association between cognition and gait in the context of DM2 and HTN. Methods: PubMed was searched to identify studies published in English before 15 April 2017 that evaluated both cognition and gait among non-demented older adults either as a function of DM2 or HTN status or as a function of continuous variables that indicate disease severity and/or management (e.g. blood pressure, HbA1C). Risk of bias was assessed by examining the method of verifying HTN/DM2 and excluding dementia as well as included covariates. Results: In the majority of studies reviewed (n = 17), both DM2 and HTN status were associated with poorer cognitive and/or gait functioning (8 out of 10 studies). In addition, in 10 out of 11 studies cognition was reliably associated with gait. For continuous variables, higher systolic blood pressure (measured with ambulatory methods) was consistently related to poorer cognition and slower gait, but other continuous variables (e.g. HbA1C) were studied inconsistently with inconclusive results. Conclusions: Cognitive and gait decrements are not only common in the context of HTN and DM2, but also are related to each other. This suggests that clinical neuropsychologists should address cognitive contributions to gait disturbance and falls in their clinical work and research with these patient populations.