Latent profiles of executive functioning in healthy young adults: evidence of individual differences in hemispheric asymmetry.

Two competing theoretical models of individual differences in executive functioning (EF) were examined: the Prefrontal Convexity Model and the Hemispheric Asymmetry Model. Neurologically healthy individuals (N = 315; mean age 20.8) completed a modified switching task (MST) and the Attention Network Test (ANT) in a single testing session. Data analysis was conducted in two phases. In the first phase (model identification), latent profile analysis was applied to MST variables measuring the abilities to form, switch, and maintain mental sets under conditions designed to tax left or right hemisphere resources. In the second phase (model validation), participant clusters obtained from the first phase were compared on the ANT. The Model Identification phase yielded a 3-profile solution consistent with the Hemispheric Asymmetry Model. Profile 1 (N = 203) was characterized by average EF performances. Profile 2 (N = 43) revealed a set maintenance weakness under non-verbal conditions. Profile 3 (N = 38) demonstrated weaknesses in cognitive flexibility combined with poor executive performances under verbal conditions. The Model Validation phase confirmed group differences. Profile 1 demonstrated average EF performances. Profile 2 demonstrated distractibility and decreased alertness, consistent with a right hemisphere weakness. Profile 3 demonstrated cognitive rigidity in the absence of external cues, consistent with a left hemisphere weakness. Individual differences in EF appear to follow a Hemispheric Asymmetry Model of EF among neurologically healthy adults. Investigating the relationship between hemispherically mediated executive functions and other individual difference factors known to confer health risk or resilience could inform numerous disciplines within the field of psychology.

The effects of poor sleep on cognitive, affective, and physiological responses to a laboratory stressor.

BACKGROUND: Recent research suggests that poor sleep may be associated with altered stress regulation. PURPOSE: This study aims to examine the associations between prior-night and prior-month sleep measures and affective, cognitive, and physiological responses to a laboratory stressor. METHODS: Ninety-eight (50 % female) young adults completed measures of sleep quality in the context of a laboratory stress study. Measures included positive (PA) and negative affects (NA) and blood pressure (BP) reactivity, as well as change in pre-sleep arousal. RESULTS: Prior-month poor sleep quality and sleep disturbances predicted dampened BP reactivity. Both prior-night and prior-month sleep quality predicted greater decrease in PA. Sleep-associated monitoring predicted NA reactivity and prolonged cognitive and affective activation. Prior-month sleep continuity predicted greater cognitive pre-sleep arousal change, and prior-month sleep quality, daytime dysfunction, and disturbances predicted prolonged cognitive and affective activation. CONCLUSION: Findings suggest that inadequate sleep confers vulnerability to poor cognitive, affective, and physiological responses to stress.

Poorer prospective memory performance is associated with reduced time monitoring among OEF/OIF/OND Veterans with a history of blast-related mild traumatic brain injury.

Objective:Prospective memory (PM) or "remembering to remember" has been shown to be reduced in Veterans with histories of mild traumatic brain injury (mTBI), particularly on tasks with high strategic demands such as recalling time-based information in the absence of external cues. This study examined whether time monitoring during a PM task was reduced in Veterans with a history of mTBI and was associated with time-based PM performance. Method:Veterans with a history of mTBI (n = 49) and Veterans without a history of TBI (n = 16) completed the Memory for Intentions Screening Test (MIST) as a measure of PM during which their time monitoring (i.e. number of clock checks) was recorded. Results:Adjusting for age, education, depression, and PTSD symptoms, negative binomial regression revealed that the mTBI group checked the clock less frequently compared to the control group (Cohen's d = 0.84, p = 0.005). Within the mTBI group, less frequent time monitoring across the entire MIST task was associated with poorer time-based MIST performance (rs = .57, p < 0.001), but not with event-based MIST (rs = .04, p = 0.768). Conclusions:Veterans with a history of mTBI evidenced significantly reduced time monitoring during a PM task compared to Veterans without a history mTBI, which was associated with strategically-demanding PM. Current findings provide that mTBI-associated difficulties with strategic aspects of PM may be due to reduced time monitoring. Future studies are needed to determine if reduced time monitoring also contributes to mTBI-associated PM difficulties in the real-world (e.g. medication non-adherence).

Self-perceived irritability among OEF/OIF/OND veterans with a history of deployment-related mTBI: Associations with prospective memory and quality of life.

Objective: Examine relationships between self-perceived irritability, prospective memory, and quality of life (QOL) following mild traumatic brain injury (mTBI). Methods: 75 OEF/OIF/OND-era Veterans (56 deployment-related mTBI; 19 no history of TBI), were administered a battery of neuropsychological tests and self-report measures of mood and QOL. Self-perceived irritability was measured using the Neurobehavioral Symptom Inventory. Prospective memory (PM) was measured using the Memory for Intentions Test (MIST). Results: Self-perceived irritability was significantly higher for Veterans with, versus without, a history of deployment-related mTBI. Among Veterans with a history of mTBI, self-perceived irritability was inversely associated with PM performance, even after adjusting for PTSD severity. Greater self-perceived irritability was also associated with higher depressive symptoms and reduced QOL for perceived physical health, psychological health, social support, and environmental factors; however, only social support remained significant after adjusting for PTSD severity. Depression symptom severity was not significantly associated with PM, suggesting that PM may be uniquely related to self-perceived irritability rather than mood dysregulation more generally. Conclusions: Findings provide preliminary evidence of a relationship between PM and self-perceived irritability in Veterans with a history of mTBI. PM and irritability may be related via their mutual reliance on high-level cognitive control. Results illustrate possible cognitive and affective factors contributing to psychological and interpersonal challenges for this population. Future investigations with larger and more diverse samples are needed to replicate findings and explore potential mechanisms linking irritability and PM following mTBI.

Associations between Intra-Individual Neurocognitive Variability and Prospective Memory in Veterans with Mild Traumatic Brain Injury History and Posttraumatic Stress Disorder.

OBJECTIVE: Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) frequently co-occur and are associated with neurocognitive intra-individual variability (IIV) and difficulty with prospective memory (PM). The current study aimed to examine associations between IIV and PM in this comorbid group. METHOD: Fifty veterans with a history of blast mTBI and current comorbid PTSD completed a standardized neurocognitive battery to measure IIV, and the Memory for Intentions Screening Test measuring PM. RESULTS: Adjusting for age, education, and race, higher IIV was associated with poorer time-based PM (p < .001, f2 = .34), but not event-based PM. In a subset of the sample with self-report data, higher IIV was associated with poorer self-reported retrospective memory, but not PM. CONCLUSIONS: Cognitive variability on a standardized neuropsychological battery was associated with strategically demanding PM, which is an ecologically relevant ability and highlights the possible connection between subtle cognitive difficulties in-clinic and those experienced in daily life.

Healthy Aging Project-Brain: A Psychoeducational and Motivational Group for Older Veterans.

INTRODUCTION: Positive health behaviors can promote brain health with age. Although healthy lifestyle factors are often encouraged by health care providers, many older adults experience difficulty incorporating these into their daily life. METHODS: To address this gap, we developed a novel health education and implementation group for older veterans (aged > 50 years). The primary objectives of this group were to provide psychoeducation about the link between behaviors and brain health, increase personal awareness of specific health behaviors, and promote behavior change through individualized goal setting, monitoring, and support. Based on input from medical providers, group content targeted behaviors known to support cognitive functioning: physical activity, sleep, cognitive stimulation, and social engagement. RESULTS: Thirty-one veterans participated in six 90-minute weekly classes and attended 5 of the 6 groups on average. The average age for the predominantly male (90%) and white (70%) group was 71 years. Qualitative feedback indicated high satisfaction and increased awareness of health behaviors. Results of paired samples t tests comparing baseline to posttreatment self-report measures revealed a significant decline in depressive symptoms (P = .01) and increases in satisfaction with life (P = .003) and self-efficacy (P = .008). CONCLUSIONS: This development project showed evidence of increased awareness of health behaviors and improved mood. Expanded data collection will strengthen power and generalizability of results (increase sample diversity). It will also allow us to examine moderating factors, such as perceived self-efficacy, on outcomes.

Reported history of childhood trauma and stress-related vulnerability: Associations with emotion regulation, executive functioning, daily hassles and pre-sleep arousal.

Childhood trauma is associated with poor health outcomes in adulthood. Mechanisms for these associations are not well understood because past studies have focused predominantly on populations that have already developed physical and mental health problems. The present study examined the association between childhood trauma and stress-related vulnerability factors in a healthy adult sample (n = 79; 68% female, mean age = 27.5, SD = 6.5). Emotion regulation difficulties were examined as a potential mediator. Participants completed baseline laboratory assessments of reported childhood trauma, emotion regulation difficulties, prior month sleep quality, baseline impedance cardiography and behavioural tests of executive functioning (EF) and a three-day experience sampling assessment protocol that included sleep diary, reported and objective pre-sleep arousal, daily hassles and reported EF difficulties. Reported history of childhood abuse was significantly associated with difficulties in emotion regulation, self-report and objective pre-sleep arousal, diary-assessed sleep quality, daily hassles and reported EF difficulties. Reported history of childhood neglect was associated with greater pre-sleep arousal and poorer EF-behavioural control. Emotion regulation difficulties mediated the relationship between childhood abuse and reported pre-sleep arousal, daily hassles and reported EF difficulties. In conclusion, history of childhood trauma is associated with a variety of stress-related vulnerability factors in healthy adults that may be viable early intervention targets.

Individual differences in executive functioning: implications for stress regulation.

BACKGROUND: Executive functioning (EF) refers to the set of neurocognitive processes that facilitate novel problem solving, modification of behavior in response to environmental changes, planning and generating strategies for complex actions, and ability to override pre-potent behavioral and emotional responses to engage in goal-directed behavior. PURPOSE: To provide an overview of research on individual differences in EF and examine the extent to which these individual differences confer risk and resilience for poor stress regulation. RESULTS: Review of the literature suggests that individual differences in EF are evident at multiple levels of analysis including genotype, endophenotype (e.g., performance on cognitive tasks), and phenotype (e.g., temperament and personality). These individual differences are associated with differential stress exposure, reactivity, recovery, and restorative processes. CONCLUSIONS: A theoretical framework that includes individual differences in EF will inform behavioral medicine research on stress risk and resilience.

The association between individual differences in executive functioning and resting high-frequency heart rate variability.

Both resting high-frequency heart rate variability (HF-HRV) and executive functioning (EF) are individual differences implicated in vulnerability to a wide range of adverse outcomes. The overlapping set of associations, along with theoretical models positing connections between the brain regions subserving the executive functions and the parasympathetic nervous system, suggest that the two factors should be correlated. Seeking to address limitations in prior research, the current study examined the association between EF, measured comprehensively with individually-administered neuropsychological tests and controlling for lower-order cognitive processes, and resting physiology, measured with impedence cardiography, in healthy, community participants (68% female; mean age = 27, SD = 6.5). Results confirmed a significant association between EF and resting HF-HRV, but no association with resting state sympathetic nervous system activation (pre-ejection period). These findings may inform future investigation of transdiagnostic mechanisms related to these two individual difference factors.

Variables associated with subjective cognitive change among Iraq and Afghanistan war Veterans with blast-related mild traumatic brain injury.

Introduction: This study investigated variables associated with subjective decline in executive function among Veterans of Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) following a history of blast-related mild traumatic brain injury (mTBI). Method: Fifty-six male U.S. Veterans (MAge = 35.3 ± 8.8 years) with a history of blast-related mTBI (6.6 ± 3.2 years post injury) completed a battery of self-report questionnaires and neuropsychological measures. Participants rated current and retrospectively estimated pre-mTBI executive function difficulties on the Frontal Systems Behavior Scale (FrSBe). A difference score (post- minus pre-mTBI ratings) was the dependent variable (∆FrSBe). Linear regression models examined variables predicting ∆FrSBe, including: pre-injury characteristics (education, premorbid intelligence), injury-related characteristics (number of blast exposures, losses of consciousness), post-injury clinical symptoms (PTSD Checklist-Military version; Pittsburgh Sleep Quality Index), and post-injury neuropsychological performances on executive function measures (Trail Making Test Part B; Controlled Oral Word Association Test; Auditory Consonant Trigrams; Wisconsin Card Sorting Test). Results: While 11% of participants had a clinically elevated pre-injury FrSBe total score, 82% had a clinically elevated post-injury FrSBe total score. Only self-reported PTSD symptom severity independently predicted perceived change in executive function. Conclusions: Many OEF/OIF/OND Veterans with a history of blast-related mTBI experience subjective decline in executive function following injury. Perceived executive function decline was associated with higher PTSD symptom severity, aligning with previous research associating PTSD with cognitive complaints. Results did not support a correspondence between perceived cognitive change and neuropsychological performances.

Nonrestorative sleep in healthy, young adults without insomnia: associations with executive functioning, fatigue, and pre-sleep arousal.

OBJECTIVES: Previous research suggests that nonrestorative sleep (NRS), even in the absence of insomnia symptoms or other sleep disorders, may be associated with daytime dysfunction. This study examined the association between NRS and daytime dysfunction in healthy adults screened for insomnia and sleep apnea. DESIGN: Multi-day assessment approach. SETTING: Community-based adults and college students. PARTICIPANTS: Healthy young adults without insomnia and sleep apnea (n = 79; 68% female, mean age = 27.5, SD = 6.5). MEASUREMENTS: Laboratory protocol included a behavioral assessment of executive functioning (EF), self-report of prior month sleep-related daytime dysfunction, and depressive symptoms in the prior two weeks. Subsequently, participants completed an experience sampling assessment that included morning ratings of NRS, repeat affect ratings throughout the day via palm-pilot, nighttime ratings of pre-sleep arousal and EF disturbances, ambulatory cardiac impedence monitoring, and wrist actigraphy. RESULTS: NRS was significantly associated with poorer performance on behaviorally-assessed EF, perceived EF difficulties, daily ratings of fatigue, and past-month reported daytime dysfunction. These associations remained significant after controlling for age and sleep duration (measured by actigraphy). NRS was also associated with increased sympathetic nervous system activation prior to bedtime. Further, reported pre-sleep arousal was associated with NRS, and this association was mediated by perceived EF difficulties. CONCLUSIONS: Findings indicate that, even among healthy, young adults without insomnia or sleep apnea, NRS is associated with poorer cognitive functioning and may be a precursor to insomnia.

Fatigue - but not mTBI history, PTSD, or sleep quality - directly contributes to reduced prospective memory performance in Iraq and Afghanistan era Veterans.

OBJECTIVE: Memory problems that affect daily functioning are a frequent complaint among Veterans reporting a history of repetitive mild traumatic brain injury (mTBI), especially in cohorts with comorbid PTSD. Here, we test the degree to which subjective sleep impairment and daytime fatigue account for the association of PTSD and self-reported mTBI history with prospective memory. METHOD: 82 Veterans with and without personal history of repeated blast-related mTBI during deployment were administered the Clinician Administered PTSD Scale (CAPS), Memory for Intentions Test (MIST), Patient Health Questionnaire-9 (PHQ-9), Neurobehavioral Symptom Inventory (NSI), and the Pittsburgh Sleep Quality Index (PSQI). Relationships between self-reported mTBI, PTSD, self-reported poor sleep and daytime fatigue, and MIST performance were modeled using partial least squares structural equation modeling (PLS-SEM). RESULTS: Reported daytime fatigue was strongly associated with poorer prospective memory performance. Poor subjective sleep quality was strongly and positively associated with reported daytime fatigue, but had no significant direct effect on prospective memory performance. PTSD diagnosis and self-reported mTBI history were only associated with prospective memory via their impact on subjective sleep quality and daytime fatigue. CONCLUSIONS: Results suggest that daytime fatigue may be a mediating factor by which both mTBI and PTSD can interfere with prospective memory. Additional attention should be given to complaints of daytime fatigue, independent of subjective sleep quality, in the clinical care of those with a self-reported history of mTBI, and/or PTSD. Further research into whether interventions that decrease daytime fatigue lead to improvement in prospective memory and subjective cognitive functioning is warranted.

On the validity of self-report assessment of cognitive abilities: Attentional control scale associations with cognitive performance, emotional adjustment, and personality.

Individual differences in attentional control involve the ability to voluntarily direct, shift, and sustain attention. In studies of the role of attentional control in emotional adjustment, social relationships, and vulnerability to the effects of stress, self-report questionnaires are commonly used to measure this construct. Yet, convincing evidence of the association between self-report scales and actual cognitive performance has not been demonstrated. Across 2 independent samples, we examined associations between self-reported attentional control (Attentional Control Scale; ACS), self-reported emotional adjustment, Five-Factor Model personality traits (NEO Personality Inventory-Revised) and performance measures of attentional control. Study 1 examined behavioral performance on the Attention Network Test (ANT; Fan, McCandliss, Sommer, Raz, & Posner, 2002) and the Modified Switching Task (MST; Suchy & Kosson, 2006) in a large sample (n = 315) of healthy young adults. Study 2 (n = 78) examined behavioral performance on standardized neuropsychological tests of attention, including Conner's Continuous Performance Test-II and subtests from the Wechsler Adult Intelligence Scales, Third Edition (WAIS-III; Psychological Corporation, 1997) and Delis-Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001). Results indicated that the ACS was largely unrelated to behavioral performance measures of attentional control but was significantly associated with emotional adjustment, neuroticism, and conscientiousness. These findings suggest that although self-reported attentional control may be a useful construct, researchers using the ACS should exercise caution in interpreting it as a proxy for actual cognitive ability or performance. (PsycINFO Database Record

Affiliative interpersonal behaviors during stress are associated with sleep quality and presleep arousal in young, healthy adults.

OBJECTIVES: This study examined the association between stress-related interpersonal behaviors, presleep arousal (PSA), and sleep quality. METHODS: Sixty-four participants (53% female) described a recent stressful interpersonal event that was coded for overall degree of affiliation (warmth vs hostility) and autonomy (independence vs interdependence). Cognitive and somatic PSA and sleep quality were examined using regression with affiliation and autonomy scores as predictors. Specific interpersonal behaviors that comprise overall affiliation were also examined. RESULTS: More affiliation (warmth) was associated with lower cognitive PSA (ß=-.32) and better sleep quality (ß=-.28). Autonomy was not associated with sleep quality or PSA. The specific behavior trust in others was associated with better sleep quality (rs=-.25). CONCLUSIONS: Behaviors during stress reflect underlying dimensions of interpersonal security. Findings underscore importance of interpersonal frameworks for understanding associations between stress and sleep, and provide support for the anthropological theory that interpersonal security is necessary for healthy sleep.

Effects of tonic and phasic respiratory sinus arrhythmia on affective stress responses.

Adaptive affective responses in the face of environmental challenges require flexible physiological responding. The present study examined the extent to which tonic respiratory sinus arrhythmia (RSA)-a putative marker of regulatory capacity-moderated the association between stress-related changes in RSA (i.e., phasic RSA) and concurrent changes in affect. Ninety-eight healthy, young adults completed ratings of affect during a resting baseline and following the recall of a recent stressor. Tonic RSA moderated the association of phasic RSA with stress-related change in positive affect (PA), such that change in RSA had a positive association with PA for individuals with higher tonic RSA and a negative association for those with lower tonic RSA. Examination of specific aspects of PA indicated that phasic RSA was positively associated with changes in ratings of attentive engagement among individuals with higher tonic RSA. These findings inform our understanding of phasic RSA and support the notion that flexible parasympathetic nervous system functioning is an important component of adaptive stress regulation.