Intraindividual Variability in Attention-Deficit/Hyperactivity Disorder: An Ex-Gaussian Approach.

Higher intraindividual variability (IIV) of response times is consistently noted in children with attention-deficit/hyperactivity disorder (ADHD). The current study investigated whether an ex-Gaussian estimate of IIV in children ages 6-13 years-old could differentiate between children with and without ADHD. Children completed a computerized go/no-go task to estimate trial-by-trial IIV and a continuous performance test (CPT) to estimate inattention and hyperactivity/impulsivity. Parents completed questionnaires assessing inattention and hyperactive/impulsive behaviors. IIV, commission errors, and attention problems as rated by parents were significantly greater in the ADHD group. Groups did not differ on errors of omission, but IIV was predictive of omission errors and parent ratings of inattention and hyperactivity/impulsivity. IIV predicted group membership (ADHD vs Control) whereas errors of omission did not. However, IIV did not improve diagnostic accuracy when parent ratings were used, such that parent ratings were superior at determining diagnosis. Current results support the use of IIV, based on the ex-Gaussian approach, as an objective measure of attention problems over omission errors on sustained attention CPT-type tasks. Additionally, while parent ratings of attention impairment remain the best predictor of ADHD diagnostic status, IIV may be helpful in determining when further assessment is required in the absence of those ratings.

Premorbid personality traits as predictors for incident predementia syndromes: a multistate model approach.

OBJECTIVE: Associations have been found between five-factor model (FFM) personality traits and risk of developing specific predementia syndromes such as subjective cognitive decline (SCD) and mild cognitive impairment (MCI). The aims of this study were to: 1) Compare baseline FFM traits between participants who transitioned from healthy cognition or SCD to amnestic MCI (aMCI) versus non-amnestic MCI (naMCI); and 2) Determine the relationship between FFM traits and risk of transition between predementia cognitive states. METHODS: Participants were 562 older adults from the Einstein Aging Study, 378 of which had at least one follow-up assessment. Baseline data collected included levels of FFM personality traits, anxiety and depressive symptoms, medical history, performance on a cognitive battery, and demographics. Follow-up cognitive diagnoses were also recorded. RESULTS: Mann-Whitney U tests revealed no differences in baseline levels of FFM personality traits between participants who developed aMCI compared to those who developed naMCI. A four-state multistate Markov model revealed that higher levels of conscientiousness were protective against developing SCD while higher levels of neuroticism resulted in an increased risk of developing SCD. Further, higher levels of extraversion were protective against developing naMCI. CONCLUSIONS: FFM personality traits may be useful in improving predictions of who is at greatest risk for developing specific predementia syndromes. Information on these personality traits could enrich clinical trials by permitting trials to target individuals who are at greatest risk for developing specific forms of cognitive impairment. These results should be replicated in future studies with larger sample sizes and younger participants.

Electrophysiological variability during tests of executive functioning: A comparison of athletes with and without concussion and sedentary control participants.

OBJECTIVE: Sport participation may benefit executive functioning (EF), but EF can also be adversely affected by concussion, which can occur during sport participation. Neural variability is an emerging proxy of brain health that indexes the brain's range of possible responses to incoming stimuli (i.e., dynamic range) and interconnectedness, but has yet to be characterized following concussion among athletes. This study examined whether neural variability was enhanced by athletic participation and attenuated by concussion. METHOD: Seventy-seven participants (18-25 years-old) were classified as sedentary controls (n = 33), athletes with positive concussion history (n = 21), or athletes without concussion (n = 23). Participants completed tests of attention switching, response inhibition, and updating working memory while undergoing electroencephalography recordings to index neural variability. RESULTS: Compared to sedentary controls and athletes without concussion, athletes with concussion exhibited a restricted whole-brain dynamic range of neural variability when completing a test of inhibitory control. There were no group differences observed for either the switching or working memory tasks. CONCLUSIONS: A history of concussion was related to reduced dynamic range of neural activity during a task of response inhibition in young adult athletes. Neural variability may have value for evaluating brain health following concussion.

Intraindividual variability measured with dispersion across diagnostic groups in a memory clinic sample.

Increased intraindividual variability (IIV) has been linked to outcomes such as cognitive decline and dementia, suggesting IIV might add valuable diagnostic information beyond traditional neuropsychological interpretation. We explored whether a subtype of IIV, dispersion, can provide additional information for dementia diagnosis. In a sample of memory clinic patients, three cognitive status groups were identified: subjective cognitive impairment (SCI; n = 85), amnestic mild cognitive impairment (a-MCI; n = 16), and dementia due to Alzheimer's disease (AD; n = 48). Dispersion was computed as intraindividual standard deviations across multiple neuropsychological measures within three cognitive domains (executive functioning; immediate and delayed memory) and was compared for each diagnostic group using profile analysis. Patients with AD and a-MCI demonstrated less dispersion than patients with SCI in delayed memory. Results support existing theoretic perspectives on cognitive variability and age-related cognitive decline but suggest floor effects underlie suppression of dispersion in amnestic cognitive presentations. Questions remain about the contribution of IIV beyond impressions of impairment versus no impairment in these constrained representations of cognitive domains. Future investigations should investigate variability in SCI groups against controls to examine whether observed dispersion similarities between SCI and a-MCI or AD in immediate memory and executive functioning are meaningful.

Exploring the impact of community-based choral participation on cognitive function and well-being for persons with dementia: evidence from the Voices in Motion project.

OBJECTIVES: Music-based interventions are postulated to mitigate cognitive decline in individuals with dementia. However, the mechanisms underlying why music-based interventions facilitate cognitive benefits remain unknown. The present study examines whether a choral intervention can modulate patterns of cognitive change in persons with dementia and whether within-person variation in affect is associated with this change. METHODS: Thirty-three older adults with dementia engaged weekly in the Voices in Motion (ViM) study consisting of 3 choral seasons spanning 18-months. Performance on the Mini-Mental State Examination (MMSE) and the Positive and Negative Affect Schedule was assessed monthly within each choral season using a longitudinal intensive repeated-measures design. Three-level multilevel models were employed to disaggregate between- and within-person effects across short- (month-to-month) and long-term (season-to-season) intervals. RESULTS: ViM participants exhibited an annual MMSE decline of 1.8 units, notably less than the clinically meaningful 3.3 units indicated by non-intervention literature. Further, variability in negative affect shared a within-person time-varying association with MMSE performance; decreases in negative affect, relative to one's personal average, were linked to corresponding improvements in cognitive function. CONCLUSION: Engagement in the ViM choral intervention may attenuate cognitive decline for persons with dementia via a reduction of psychological comorbidities such as elevated negative affect.

Choral singing and dementia: Exploring musicality as embodied and relational accomplishment.

This study explored the impact of participation in Voices in Motion (ViM), an intergenerational community choir program that involved persons with dementia, care partners, and high school students in Victoria, British Columbia, Canada. Data came from interviews with 23 duets, each consisting of a person with dementia and their care partner; additionally, five focus groups with 29 students across two ViM choirs were conducted. Choir rehearsals and concerts were also observed. The analysis revealed that those with dementia have an embodied ability to fully participate in the choir and perform songs despite cognitive decline and memory loss. Involvement in the choirs also facilitated the emergence of strong social relationships among participants while students reported gaining a deeper understanding of the everyday experiences of living with dementia. Through well-attended concerts and performances at public events, ViM also helped re-humanize persons living with dementia by challenging the narrative of decline and its associated stigma.

Parameterizing Practice in a Longitudinal Measurement Burst Design to Dissociate Retest Effects From Developmental Change: Implications for Aging Neuroscience.

Background: In longitudinal designs, the extraneous influence of retest effects can confound and obscure estimates of developmental change. The current study provides a novel approach to independently parameterize short-term retest effects and long-term developmental change estimates by leveraging a measurement burst design and three-level multilevel modeling. We further employ these short- and long-term slopes as predictors of cognitive status at long-term follow-up assessments. Methods: Participants included 304 older adults from Project MIND: a longitudinal measurement burst study assessing cognitive performance across both biweekly sessions and annual retests. Participants were classified as either Healthy controls (HC) or Cognitively Impaired, not Demented (CIND) at baseline, the final burst assessment (Year 4), and at an additional four-year follow-up (Year 8). Response time inconsistencies (RTI) were computed at each burst occasion for a simple choice response time (CRT) task and a one-back response time (BRT) task. Three-level multilevel models were employed to simultaneously examine change in RTI for both CRT and BRT across weeks within years, as well as across years, in order to dissociate within-individual retest effects (short-term) from developmental (long-term) change slopes. Individual slopes were then extracted and utilized in a series of multinomial logistic regression equations to contrast short- vs. long-term RTI change as predictors of cognitive status. Results: Separately parameterizing short- and long-term change estimates yielded distinct patterns of variation. CRT RTI remained stable across short-term weekly assessments, while significantly increasing across years. In contrast, BRT RTI decreased significantly across short-term assessments but showed no change across long-term assessments. After dissociating change estimates, short-term BRT as well as long-term CRT and BRT estimates predicted cognitive status at long-term follow-ups; increases in RTI, suggesting either an inability to benefit from retest or process-based developmental decline, were associated with an increased likelihood of being classified as CIND. Conclusions: We showcase an innovative approach to dissociate retest effects from developmental change across and within individuals. Accurately parameterizing these distinct change estimates can both reduce systematic bias in longitudinal trend estimates as well as provide a clinically useful tool by utilizing retest effects to predict cognitive health and impairment.

CVLT-II short form forced choice recognition in a clinical dementia sample: Cautions for performance validity assessment.

Performance validity tests are susceptible to false positives from genuine cognitive impairment (e.g., dementia); this has not been explored with the short form of the California Verbal Learning Test II (CVLT-II-SF). In a memory clinic sample, we examined whether CVLT-II-SF Forced Choice Recognition (FCR) scores differed across diagnostic groups, and how the severity of impairment [Clinical Dementia Rating Sum of Boxes (CDR-SOB) or Mini-Mental State Examination (MMSE)] modulated test performance. Three diagnostic groups were identified: subjective cognitive impairment (SCI; n = 85), amnestic mild cognitive impairment (a-MCI; n = 17), and dementia due to Alzheimer's Disease (AD; n = 50). Significant group differences in FCR were observed using one-way ANOVA; post-hoc analysis indicated the AD group performed significantly worse than the other groups. Using multiple regression, FCR performance was modeled as a function of the diagnostic group, severity (MMSE or CDR-SOB), and their interaction. Results yielded significant main effects for MMSE and diagnostic group, with a significant interaction. CDR-SOB analyses were non-significant. Increases in impairment disproportionately impacted FCR performance for persons with AD, adding caution to research-based cutoffs for performance validity in dementia. Caution is warranted when assessing performance validity in dementia populations. Future research should examine whether CVLT-II-SF-FCR is appropriately specific for best-practice testing batteries for dementia.

Intraindividual variability in executive and motor control tasks in children with attention deficit hyperactivity disorder.

OBJECTIVE: Emerging evidence highlights intraindividual variability (IIV) during executive function (EF) tasks as a reliable endophenotype of Attention Deficit/Hyperactivity Disorder (ADHD) and as contributing to motor dysregulation and hyperactive-impulsive behaviors. This study examined the relationship between EF and motor control in children with and without ADHD. METHOD: Ninety-seven children (6-13 years) completed standardized and experimental tasks of executive and motor control. Primary caregivers completed a semi-structured interview, and behavioral rating forms for ADHD symptoms and EF. RESULTS: Children with ADHD demonstrated lower performance on motor dexterity and sequencing tasks, and greater IIV during EF tasks with lower cognitive demand. IIV accounted for ADHD symptoms of hyperactivity, beyond age and motor dexterity. IIV from EF measures with lower cognitive demand was also sensitive to ADHD symptoms. CONCLUSION: IIV metrics may tap into the motor regulation challenges associated with ADHD, as well as attentional lapsing at lower levels of cognitive demand.

A socially-engaged lifestyle moderates the association between gait velocity and cognitive impairment.

Objective: Cognitive status has been linked to impaired gait velocity, and diminished social and physical engagement. To date, the potential moderating influence of lifestyle engagement on gait-cognitive status associations has not been systematically explored. The present investigation examines whether a socially- or physically-engaged lifestyle moderates the association between diminished gait velocity and likelihood of amnestic mild cognitive impairment (a-MCI) classification.Methods: Participants (aged 65+, Mage=73 years) were classified as either healthy controls (n = 30) or a-MCI (n = 24), using neuropsychological test scores and clinical judgement. Gait velocity was indexed using a GAITRite computerized walkway, engaged lifestyle (social and physical subdomains) were measured using a well-validated self-report measure, the revised Activity Lifestyle Questionnaire.Results: Logistic regression, evaluating likelihood of a-MCI classification, yielded a significant interaction between a socially-engaged lifestyle and gait velocity (b=.01, SE=.003, p=.015). Follow-up simple effects were derived for two levels (+/-1SD) of social engagement; for individuals 1 SD below the mean, the association between gait velocity and increased likelihood of a-MCI classification was exacerbated (probability of a-MCI classification for those with slower gait velocity was 60% higher for individuals 1 SD below vs 1 SD above the mean of social engagement). Physically-engaged lifestyle did not significantly moderate the gait-cognitive status association.Conclusions: The significant moderating influence of social engagement has several implications, including the likelihood that distinct mechanisms underlie the relationships of social engagement and gait velocity to cognitive function, the value of social variables for well-being, and the potential utility of socially-based interventions that may prevent/delay a-MCI onset.

The Ups and Downs of Cognitive Function: Neuroticism and Negative Affect Drive Performance Inconsistency.

OBJECTIVES: Response time inconsistency (RTI)-or trial-to-trial variability in speeded performance-is increasingly recognized as an indicator of transient lapses of attention, cognitive health status, and central nervous system integrity, as well as a potential early indicator of normal and pathological cognitive aging. Comparatively, little research has examined personality predictors of RTI across adulthood. METHODS: We evaluated the association between the personality trait neuroticism and RTI in a community-dwelling sample of 317 adults between the ages of 19-83 and tested for two indirect pathways through negative affect (NA) and cognitive interference (CI). RESULTS: The personality trait neuroticism predicted greater RTI independent of mean response time performance and demographic covariates; the results were age-invariant. Furthermore, NA (but not CI) accounted for this association and moderated mediation model results indicated that older adults were more vulnerable to the adverse effects of NA. DISCUSSION: Neuroticism predicts greater RTI irrespective of mean performance and this effect is driven largely by heightened negative emotionality that may be particularly detrimental for older adults.

Associations Between Control Beliefs and Response Time Inconsistency in Older Adults Vary as a Function of Attentional Task Demands.

OBJECTIVE: Control beliefs are established correlates of cognitive aging. Despite recent demonstrations that response time inconsistency (RTI) represents a proxy for cognitive processing efficiency, few investigations have explored links between RTI and psychosocial correlates. We examined associations among RTI and control beliefs (perceived competence and locus of control) for two choice-response time (RT) tasks varying in their attentional demands. METHOD: Control beliefs and RTI were measured weekly for 5 weeks in a sample of 304 community-dwelling older adults (Mage = 74.11 years, SD = 6.05, range = 64-92, 68.58% female). RESULTS: Multilevel models revealed that for the attentionally demanding task, reporting higher perceived competence than usual was associated with lower RTI for relatively younger participants and greater RTI for relatively older participants. For the less attentionally demanding task, reporting higher perceived competence than usual was associated with lower RTI for relatively older participants. Links between locus of control and RTI were comparatively scant. DISCUSSION: Our findings suggest that control beliefs may have adaptive and maladaptive influences on RTI, depending on dimension of control beliefs, individual differences in level of control beliefs and age, as well as attentional task demands. Both for whom and when control beliefs can be leveraged to optimize cognitive aging are discussed.

Longitudinal changes in response time mean and inconsistency exhibit predictive dissociations for risk of cognitive impairment.

OBJECTIVE: Although mean response time (RT) is a commonly used indicator of cognitive function, trial-to-trial variability (RT inconsistency [RTI]) represents a dissociable dimension of performance arguably more sensitive for characterizing cognitive status. The present study explores whether (a) RT mean or inconsistency reflects a more dispositional characteristic of an individual, particularly with increased cognitive impairment; (b) RT mean and inconsistency exhibit comparable patterns of change across a 4-year period; and (c) these rates of change differentially predict cognitive status. METHOD: A sample of 304 adults (64-92 years) at baseline completed a choice RT task weekly for 4-5 weeks, repeating this protocol and a basic neuropsychological assessment annually for 4 years. Three cognitive status subgroups were identified at baseline and Year 4: healthy controls (HCs), as well as cognitively impaired-not-demented (CIND) status based upon single (CIND-S) and multiple (CIND-M) domains. RESULTS: RTI was disproportionately stable among cognitively compromised individuals at baseline, suggesting that increased RTI is a dispositional characteristic reflecting underlying changes in psychological process or neurological function. Notably, 4-year trajectories of change for RT mean versus RTI were dissociable; whereas the HC and CIND-S groups exhibited faster mean RTs over time, CIND-M individuals exhibited significant RTI increases. Multinomial logistic regressions demonstrated that greater RTI at baseline (OR = 2.58, p < .01) and steeper 4-year increases (OR = 4.40, p < .01) were linked to increased likelihood of CIND-M classification at Year 4, independent of age, education, chronic health conditions, and mean RT. CONCLUSIONS: RT mean and RTI confer distinct sources of information about cognitive function and status. Overall, RTI holds promise as an early indicator of normal and pathological cognitive aging. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

White Matter Integrity Is Associated With Intraindividual Variability in Neuropsychological Test Performance in Healthy Older Adults.

Inconsistency of performance across neuropsychological testing instruments (dispersion) shows sensitivity to acquired injury and neurodegenerative pathology in older adults. The underlying neural correlates have remained speculative however, in spite of known white matter degradation seen in conjunction with elevated inconsistency in related operationalizations of intraindividual variability. Consistently, these operationalizations have controlled for artifactual age-related variance to increase measurement sensitivity of CNS dysfunction. In this study, dispersion was examined alongside composite scores of memory and executive functioning from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Forty-four healthy older adults (M = 72.0, SD = 6.4) underwent Diffusion Tensor Imaging (DTI) and neuropsychological testing spanning a range of cognitive domains. The results replicated previous findings, demonstrating reduced microstructural integrity with advanced age and increased integrity in high memory and executive functioning performers, across all major white matter tracts. With age first regressed from the composite scores, significant associations remained between greater executive functioning scores and greater microstructural integrity in the genu of the corpus callosum, right anterior corona radiata, anterior, posterior and rentrolenticular parts of right internal capsule, as well as right posterior thalamic radiation. With age regressed from the dispersion scores, greater values were primarily associated with decreased white matter integrity in the body and genu of corpus callosum, anterior corona radiata bilaterally and left superior longitudinal fasciculus. Dispersion is easily computed across speeded and accuracy-based measures and shows promise in detecting white matter damage, beyond that seen in the typical aging process. This appears to be the first investigation of neural correlates associated with increased dispersion.

Intraindividual variability in children is related to informant ratings of attention and executive function.

Objective: Attention and executive function (EF) deficits are ubiquitous in neurodevelopmental disorders including Attention Deficit/Hyperactivity Disorder (ADHD), as are high levels of intraindividual variability (IIV). Attention and EF are typically assessed using informant ratings and objective measures; however, discrepancies between different metrics often make it difficult to fully characterize a child's attention capabilities, and IIV has been proposed as a potentially useful discriminator. Our objective was to explore the relationship between IIV, using the residualized intraindividual standard deviation (rISD) method, and informant ratings of attention and EF in a mixed pediatric sample, to determine the potential utility of IIV for aiding attention diagnostics. Another commonly used, though controversial, IIV indicator, the coefficient of variation (ICV), was calculated for comparison purposes. Method: We assessed 51 children with varying degrees of attention and EF deficits. Measures included parent and teacher responses on the Comprehensive Executive Function Inventory (CEFI) and response times (RT) on a go/no-go task, which were used to estimate IIV. Results: Mean RT, rISD, and ICV were significantly related to parent and teacher ratings of attention, though ICV showed a relatively weaker association. rISD also showed associations with parent ratings of working memory and self-monitoring, as well as teacher ratings of working memory. Conclusion: The significant, and relatively stronger, relationship between rISD and parent and teacher ratings of attention supports the use of this metric, compared to mean RT and ICV. The rISD indicator of IIV thus shows potential utility as a unique and objective measure of attention in children across various neurodevelopmental disorders and, with additional research, may prove useful for diagnosis of attention problems.

The influence of social support and perceived stress on response time inconsistency.

OBJECTIVES: Lack of social support and high levels of stress represent potentially modifiable risk factors for cognitive aging. In this study we examined the relationships between these two risk factors and response time inconsistency (RTI), or trial-to-trial variability in choice response time tasks. RTI is an early indicator of declining cognitive health, and examining the influence of modifiable psychosocial risk factors on RTI is important for understanding and promoting cognitive health during adulthood and old age. METHODS: Using data from a community sample study (n = 317; Mage = 49, range = 19-83), we examined the effects of social support, including size of network and satisfaction with support, global perceived stress, and their interactions on RTI. RESULTS: Neither size of network nor satisfaction with support was associated with RTI independent of perceived stress. Stress was positively associated with increased RTI on all tasks, independent of social support. Perceived stress did not interact with either dimension of social support to predict RTI, and perceived stress effects were invariant across age and sex. CONCLUSION: Perceived stress, but not social support, may be a unique and modifiable risk factor for normal and pathological cognitive aging. Discussion focuses on the importance of perceived stress and its impact on RTI in supporting cognitive health in adulthood and old age.

A Comprehensive Comparison of Quantifications of Intraindividual Variability in Response Times: A Measurement Burst Approach.

OBJECTIVES: To formally identify and contrast the most commonly-employed quantifications of response time inconsistency (RTI) and elucidate their utility for understanding within-person (WP) and between-person (BP) variation in cognitive function with increasing age. METHOD: Using two measurement burst studies of cognitive aging, we systematically identified and computed five RTI quantifications from select disciplines to examine: (a) correlations among RTI quantifications; (b) the distribution of BP and WP variation in RTI; and (c) the comparability of RTI quantifications for predicting attention switching. RESULTS: Comparable patterns were observed across studies. There was significant variation in RTI BP as well as WP across sessions and bursts. Correlations among RTI quantifications were generally strong and positive both WP and BP, except for the coefficient of variation. Independent prediction models indicated that slower mean response time (RT) and greater RTI were associated with slower attention switching both WP and BP. For selecting simultaneous prediction models, collinearity resulted in inflated standard errors and unstable model estimates. DISCUSSION: RTI reflects a novel dimension of performance that is a robust and theoretically informative predictor of BP and WP variation in cognitive function. Among the plenitude of RTI quantifications, not all are interchangeable, nor of comparable predictive utility.

Daily Stress Processes as Contributors to and Targets for Promoting Cognitive Health in Later Life.

OBJECTIVE: The aim of this study was to test the hypothesis that daily stress processes, including exposure and emotional reactivity to daily stressors, are associated with response time inconsistency (RTI), an indicator of processing efficiency and cognitive health. Furthermore, we considered daily stress-cognitive health associations at the level of individual differences and within-persons over time. METHODS: Participants were 111 older adults (mean = 80 years, range = 66-95 years) enrolled in a measurement burst study where assessments of response time-based cognitive performance, stressful experiences, and affect were administered on each of 6 days for a 2-week period. This protocol was repeated every 6 months for 2.5 years. Multilevel modeling was used to examine frequency of stressor exposure, nonstressor affect, and affect reactivity to daily stressors as individual difference and time-varying predictors of RTI. RESULTS: Between-persons, higher levels of nonstressor negative affect (b = 0.41, 95% confidence interval [CI] = -0.01 to 0.83, p = .055) and negative affect reactivity (b = 0.80, 95% CI = 0.18 to 1.42, p = .012) were associated with greater RTI. Within-persons over time, higher levels of negative affect (b = 0.20, 95% CI = 0.06 to 0.34, p = .006) and negative affect reactivity (b = 0.13, 95% CI = 0.02 to 0.24, p = .018) were associated with increased RTI among the oldest portion of the sample, whereas higher levels of positive affect (b = -0.11, 95% CI = -0.21 to -0.02, p = .019) were associated with reduced RTI. CONCLUSIONS: Negative affect reactions to daily stressors are associated with compromised RTI both between and within-persons. Findings suggest that emotional reactions to daily stressors contribute to compromise older adults' cognitive health, whereas increased positive affect may be beneficial.

Decomposing the within-person and between-person sources of variation in physical activity-cognition associations for low-active older adults.

OBJECTIVES: To examine within-person and between-person sources of variation in the relationship between physical activity and cognition in older adults participating in a walking program. To explore whether demographic, health and fitness variables, and their interactions with activity, are significant predictors of cognition. DESIGN: Brief longitudinal burst design. PARTICIPANTS: 118 participants (91 females, mean age = 72.81 + 5.24 years). MAIN OUTCOME MEASURES: Cognition, self-reported moderate-to-vigorous walking and self-reported moderate-to-vigorous physical activity were assessed at baseline and 6, 9, 12 and 16 weeks follow-up. Attendance at weekly walks was also recorded. RESULTS: Within-persons, changes in physical activity were related to select measures of executive functioning, with increased activity predictive of better cognition (three of four cognitive functions, p<.05). Between-persons, activity was also associated with cognition (two of four cognitive functions, p<.05). Younger age and higher education were related to better cognition. Interactions of demographic, health, and fitness variables with changes in within-person activity were generally non-significant. CONCLUSION: The results highlight the importance of distinguishing within- from between-person effects in longitudinal analyses of the association between physical activity and cognition. This stringent within-person test of association underscores the potential value of simple physical activity interventions for improving cognitive function.

Contrasting olfaction, vision, and audition as predictors of cognitive change and impairment in non-demented older adults.

OBJECTIVE: This study examines the relative utility of a particular class of noninvasive functional biomarkers-sensory functions-for detecting those at risk of cognitive decline and impairment. Three central research objectives were examined including whether (a) olfactory function, vision, and audition exhibited significant longitudinal declines in nondemented older adults; (b) multiwave change for these sensory function indicators predicted risk of mild cognitive impairment (MCI); and (c) change within persons for each sensory measure shared dynamic time-varying associations with within-person change in cognitive functioning. METHOD: A longitudinal sample (n = 408) from the Victoria Longitudinal Study was assembled. Three cognitive status subgroups were identified: not impaired cognitively, single-assessment MCI, and multiple-assessment MCI. RESULTS: We tested independent predictive associations, contrasting change in sensory function as predictors of cognitive decline and impairment, utilizing both linear mixed models and logistic regression analysis. Olfaction and, to a lesser extent, vision were identified as the most robust predictors of cognitive status and decline; audition showed little predictive influence. CONCLUSIONS: These findings underscore the potential utility of deficits in olfactory function, in particular, as an early marker of age- and pathology-related cognitive decline. Functional biomarkers may represent potential candidates for use in the early stages of a multistep screening approach for detecting those at risk of cognitive impairment, as well as for targeted intervention. (PsycINFO Database Record