Sleep and the gut microbiota in preschool-aged children.

Sleep plays a significant role in the mental and physical development of children. Emerging evidence in animals and human adults indicates a relationship between sleep and the gut microbiota; however, it is unclear whether the sleep of preschoolers during a key developmental period, associates with features of their gut microbiota. The objective of this study was to assess the relationship between sleep and gut microbiota in preschool-aged children (4.37 ± 0.48 years, n = 143). Sleep measures included total night-time sleep (TST), sleep efficiency (SE), and wake-time after sleep onset (WASO) assessed using actigraphy. Beta-diversity differences between children with low and high TST (p = .048) suggest gut microbiota community differences. Particularly, relative abundance of Bifidobacterium was higher in the high TST group and Bacteroides, was higher in children who had greater SE and less WASO (LDA score >2). In contrast, some Lachnospiraceae members including Blautia and Coprococcus 1 were associated with shorter night-time sleep duration and less efficiency, respectively. We also found a group of fecal metabolites, including specific neuroactive compounds and immunomodulating metabolites were associated with greater sleep efficiency and less time awake at night. Notably, tryptophan and its metabolizing products were higher in children who had higher SE or lower WASO (LDA score >2); concentration of propionate was higher in children with less WASO (p = .036). Overall, our results reveal a novel association between sleep and gut microbiota in preschool-aged children. Longer night-time sleep and greater sleep efficiency were associated with specific commensal bacteria that may regulate sleep through modulating neurotransmitter metabolism and the immune system.

No effect of mindfulness-based cancer recovery on cardiovascular or cortisol reactivity in female cancer survivors.

Psychosocial stress in cancer survivors may contribute to compromised quality of life and negative cancer outcomes, which can be exacerbated by poor coping skills and emotional reactivity. Mindfulness based interventions (MBIs) have shown effectiveness in reducing stress, improving quality of life and coping skills in cancer survivors. We tested whether an MBI would also improve reactivity to an acute laboratory stress task. A total of 77 women with a cancer diagnosis were recruited for a waitlist-controlled trial of Mindfulness-Based Cancer Recovery (MBCR). Participants completed a laboratory-based psychosocial stress paradigm (the Trier Social Stress Test-TSST) pre- and post-intervention, throughout which cortisol and cardiovascular profiles were measured. Neither cortisol nor cardiovascular reactivity to the TSST was changed pre-to post intervention, either between or within groups. Blunted cortisol, but not cardiovascular, reactivity was observed across both groups, which may have contributed to the lack of intervention effect. Previous research suggests that diurnal cortisol is blunted following cancer treatment; the current findings suggest this blunting may also occur during exposure to acute stress.

Genetic Risk, Vascular Function, and Subjective Cognitive Complaints Predict Objective Cognitive Function in Healthy Older Adults: Results From the Brain in Motion Study.

Aging is associated with subjective memory complaints. Approximately half of those with subjective memory complaints have objective cognitive impairment. Previous studies have provided evidence of an association between genetic risk for Alzheimer's disease (AD) and dementia progression. Also, aging is a significant risk factor for vascular pathology that may underlie at least some of the cognitive changes. This study investigates the relative contribution of subjective cognitive complaints (SCC), vascular function, and genetic risk for dementia in predicting objective cognitive performance. Multiple regression and relative importance analysis were used to investigate the relative contribution of vascular function, self-reported SCC, and dementia genetic risk, in predicting objective cognition in a sample of 238 healthy community-dwelling older adults. Age, sex, premorbid cognitive abilities, subjective verbal memory complaints, higher cerebrovascular blood flow during submaximal exercise, and certain dementia risk alleles were significant predictors of worse objective verbal memory performance (p < 0.001, R 2 = 35.2-36.4%). Using relative importance analysis, subjective verbal memory complaints, and certain dementia risk alleles contributed more variance than cerebrovascular measures. These results suggest that age-related changes in memory in healthy older adults can be predicted by subjective memory complaints, genetic risk, and to a lesser extent, cerebrovascular function.

Aerobic exercise improves cognition and cerebrovascular regulation in older adults.

OBJECTIVE: To test the hypothesis that aerobic exercise is associated with improvements in cognition and cerebrovascular regulation, we enrolled 206 healthy low-active middle-aged and older adults (mean ± SD age 65.9 ± 6.4 years) in a supervised 6-month aerobic exercise intervention and assessed them before and after the intervention. METHODS: The study is a quasi-experimental single group pre/postintervention study. Neuropsychological tests were used to assess cognition before and after the intervention. Transcranial Doppler ultrasound was used to measure cerebral blood flow velocity. Cerebrovascular regulation was assessed at rest, during euoxic hypercapnia, and in response to submaximal exercise. Multiple linear regression was used to examine the association between changes in cognition and changes in cerebrovascular function. RESULTS: The intervention was associated with improvements in some cognitive domains, cardiorespiratory fitness, and cerebrovascular regulation. Changes in executive functions were negatively associated with changes in cerebrovascular resistance index (CVRi) during submaximal exercise (ß = -0.205, p = 0.013), while fluency improvements were positively associated with changes in CVRi during hypercapnia (ß = 0.106, p = 0.03). CONCLUSION: The 6-month aerobic exercise intervention was associated with improvements in some cognitive domains and cerebrovascular regulation. Secondary analyses showed a novel association between changes in cognition and changes in cerebrovascular regulation during euoxic hypercapnia and in response to submaximal exercise.

Hot flashes are associated with altered brain function during a memory task.

OBJECTIVE: Vasomotor symptoms (VMS) are associated with decreased memory performance and alterations in brain function. We conducted a preliminary examination of VMS and patterns of brain activity during a verbal memory task to provide insights into the VMS-related brain mechanisms that can contribute to memory problems in midlife women. METHODS: Fourteen postmenopausal women (mean age 53.5, 64% African-American) with moderate-to-severe VMS (>35/wk) and not taking hormone therapy completed functional magnetic resonance imaging (fMRI) assessments during word encoding and recognition, 24-hour physiologic VMS monitoring, symptom questionnaires, and two verbal memory tests. RESULTS: In regression analyses, a higher number of physiologic VMS, but not reported VMS, was associated with worse verbal memory on immediate and delayed logical memory (r = 0.53 and r = 0.72, P < 0.05). On fMRI assessments, a higher number of physiologic VMS, but not subjective VMS, was associated with greater activation in the left orbitofrontal cortex, left medial and superior frontal gyrus, right superior frontal gyrus, and right parahippocampal gyrus during the encoding task (P < 0.005). During the recognition task, physiologic VMS were associated with greater activation in the left medial and superior frontal gyrus, left parahippocampal gyrus and hippocampus, right medial and superior frontal gyrus, right parahippocampal gyrus and hippocampus (P < 0.005), and with decreased activation in the ventral medial prefrontal cortex (P < 0.005). Those associations were independent of symptoms and hormone levels. CONCLUSIONS: Preliminary data suggest that VMS may contribute to memory performance through effects on the hippocampus and prefrontal cortex. Larger studies are warranted to determine the robustness of these initial observations. : Video Summary:http://links.lww.com/MENO/A508.

Video Summary:http://links.lww.com/MENO/A508.

Cognitive Effects of Repeated Acute Exposure to Very High Altitude Among Altitude-Experienced Workers at 5050 m.

Background: We investigated altitude effects on different cognitive domains among perennial shift-workers at the Atacama Large Millimeter/submillimeter Array Observatory (5050 m), Chile. Materials and Methods: Twenty healthy male workers were recruited and assigned to either a moderate-altitude first (MAF group, Test 1: 2900 m and Test 2: 5050 m) or to a high-altitude first (HAF group, Test 1: 5050 m and Test 2: 2900 m). Test 1 was conducted at the beginning and Test 2 at the end of the shift-work week. Processing speed (RTI, reaction time), attention (AST, attention-switching task, and RVP, rapid visual processing), and executive function (OTS, One Touch Stockings of Cambridge) were assessed. Results: Of the three cognitive domains assessed, only processing speed showed altitude-at-test group interaction (RTI median five choice reaction time: F1, 17 = 6.980, [Formula: see text] = 0.291, p = 0.017). With acclimatization, there was a decrease in AST reaction latency mean (t17 = -2.155, dz = 1.086, p = 0.046), an increase in RVP accuracy (t17 = 2.733, dz = 1.398, p = 0.014), and a decrease in OTS mean latency first choice (t17 = -2.375, dz = 1.211, p = 0.03). Decreased variability in cognitive function was observed in AST reaction latency standard deviation (t17 = -2.524, dz = 1.282, p = 0.022) and in RVP response latency standard deviation (t17 = -2.35, dz = 1.177, p = 0.03) with acclimatization. At 5050 m of elevation, SpO2 was positively correlated with executive function in the MAF group (OTS problems solved on first choice: r(5) = 0.839, p = 0.018) and negatively correlated with executive function latency standard deviations in the HAF group (OTS latency to first choice standard deviation: r(10) = -0.618, p = 0.032). Conclusions: Our findings highlight the importance of acclimatization and improvement of blood oxygen level, even among high altitude-experienced workers, to optimize performance of cognitively demanding work and reduce high altitude-associated health risks.

Aerobic exercise increases cortisol awakening response in older adults.

Evidence from both preclinical and clinical studies suggests aerobic exercise may dampen age-related decline in cognitive performance. Alterations in hypothalamic-pituitary-adrenal (HPA) axis function and reactivity may be a mechanism by which aerobic exercise benefits cognitive performance, and reduces perceived stress. This investigation was completed as an ancillary investigation of the Brain in Motion (BIM) study, a 6-month supervised aerobic exercise intervention. Participants were generally healthy and screened for inclusion/exclusion criteria for the parent study. Thirty-eight participants were recruited (Mean age = 65.0 [SD = 5.1]; 60% female) and the final longitudinal sample was 32 participants. Participants provided a passive drool sample at: waking, 15, 30, and 45 min post-waking to assess the cortisol awakening response (CAR) and 3, 6, 9, and 12 h post-waking to assess daily area under the curve for cortisol. Salivary cortisol was quantified by liquid chromatography coupled to tandem mass spectrometry. The exercise intervention increased CAR but no differences were observed in daily AUC. In addition, larger increases in CAR were positively associated with greater decreases in subjective stress. Thus, aerobic exercise improved the CAR in otherwise healthy, but sedentary older adults and greater improvements in CAR were associated with greater reductions in perceived stress.

Peripheral oxytocin and vasopressin modulates regional brain activity differently in men and women with schizophrenia.

BACKGROUND: Oxytocin (OT) and arginine vasopressin (AVP) exert sexually dimorphic effects on cognition and emotion processing. Abnormalities in these hormones are observed in schizophrenia and may contribute to multiple established sex differences associated with the disorder. Here we examined sex-dependent hormone associations with resting brain activity and their clinical associations in schizophrenia patients. METHODS: OT and AVP serum concentrations were assayed in 35 individuals with schizophrenia (23 men) and 60 controls (24 men) from the Chicago BSNIP study site. Regional cerebral function was assessed with resting state fMRI by measuring the amplitude of low-frequency fluctuations (ALFF) which are believed to reflect intrinsic spontaneous neuronal activity. RESULTS: In female patients, lower OT levels were associated with lower ALFF in frontal and cerebellar cortices (p's < 0.05) and in female controls AVP levels were inversely associated with ALFF in the frontal cortex (p = 0.01). In male patients, lower OT levels were associated with lower ALFF in the posterior cingulate and lower AVP levels were associated with lower ALFF in frontal cortex (p's < 0.05). In male controls, lower OT levels were associated with lower ALFF in frontal cortex and higher ALFF in the thalamus (p's < 0.05). There were some inverse ALFF-behavior associations in patients. CONCLUSIONS: Alterations in peripheral hormone levels are associated with resting brain physiology in a sex-dependent manner in schizophrenia. These effects may contribute to sex differences in psychiatric symptom severity and course of illness in schizophrenia.

Effects on Cognitive Functioning of Acute, Subacute and Repeated Exposures to High Altitude.

Objective: Neurocognitive functions are affected by high altitude, however the altitude effects of acclimatization and repeated exposures are unclear. We investigated the effects of acute, subacute and repeated exposure to 5,050 m on cognition among altitude-naïve participants compared to control subjects tested at low altitude. Methods: Twenty-one altitude-naïve individuals (25.3 ± 3.8 years, 13 females) were exposed to 5,050 m for 1 week (Cycle 1) and re-exposed after a week of rest at sea-level (Cycle 2). Baseline (BL, 520 m), acute (Day 1, HA1) and acclimatization (Day 6, HA6, 5,050 m) measurements were taken in both cycles. Seventeen control subjects (24.9 ± 2.6 years, 12 females) were tested over a similar period in Calgary, Canada (1,103 m). The Reaction Time (RTI), Attention Switching Task (AST), Rapid Visual Processing (RVP) and One Touch Stockings of Cambridge (OTS) tasks were administered and outcomes were expressed in milliseconds/frequencies. Lake Louise Score (LLS) and blood oxygen saturation (SpO2) were recorded. Results: In both cycles, no significant changes were found with acute exposure on the AST total score, mean latency and SD. Significant changes were found upon acclimatization solely in the altitude group, with improved AST Mean Latency [HA1 (588 ± 92) vs. HA6 (526 ± 91), p < 0.001] and Latency SD [HA1 (189 ± 86) vs. HA6 (135 ± 65), p < 0.001] compared to acute exposure, in Cycle 1. No significant differences were present in the control group. When entering Acute SpO2 (HA1-BL), Acclimatization SpO2 (HA6-BL) and LLS score as covariates for both cycles, the effects of acclimatization on AST outcomes disappeared indicating that the changes were partially explained by SpO2 and LLS. The changes in AST Mean Latency [ΔBL (-61.2 ± 70.2) vs. ΔHA6 (-28.0 ± 58), p = 0.005] and the changes in Latency SD [ΔBL (-28.4 ± 41.2) vs. ΔHA6 (-0.2235 ± 34.8), p = 0.007] across the two cycles were smaller with acclimatization. However, the percent changes did not differ between cycles. These results indicate independent effects of altitude across repeated exposures. Conclusions: Selective and sustained attention are impaired at altitude and improves with acclimatization.The observed changes are associated, in part, with AMS score and SpO2. The gains in cognition with acclimatization during a first exposure are not carried over to repeated exposures.

Association between glycemic load and cognitive function in community-dwelling older adults: Results from the Brain in Motion study.

BACKGROUND: Impaired glucose tolerance is a risk factor for non-age-related cognitive decline and is also associated with measures of physical activity (PA) and cardiorespiratory fitness (CRF). A low glycemic load (GL) diet can aid in the management of blood glucose levels, but little is known about its effect on cognition with poor glucoregulation. OBJECTIVE: We assessed the relation between GL and cognitive function by glucoregulation and possible mediatory effects by CRF and PA in older adults from the Brain in Motion Study. DESIGN: A cross-sectional analysis of 194 cognitively healthy adults aged ≥55 years (mean = 65.7, SD = 6.1) was conducted. GL was assessed using a quantitative food frequency questionnaire, and glucoregulation was characterized on the HOMA-IR index. Subjects also completed a cognitive assessment, CRF testing, a validated self-reported PA questionnaire, and a blood draw. Multiple linear regression models adjusted for significant covariates were used to evaluate the relation between GL and cognition, and mediation by CRF and PA was also assessed. RESULTS: GL was inversely associated with global cognition (ß = -0.014; 95% CI -0.024, -0.004) and figural memory (ß = -0.035; 95% CI -0.052, -0.018) in subjects with poor glucoregulation. Neither CRF nor PA mediated these relations. In subjects with good glucoregulation, no association was found between GL and cognitive function (p > 0.05). CONCLUSIONS: A low GL diet is associated with better cognitive function in older adults with poor glucoregulation. This study provides supportive evidence for the role of GL in maintaining better cognitive function during the aging process.

Sex differences in age-related changes in the sleep-wake cycle.

Age-related changes in sleep and circadian regulation occur as early as the middle years of life. Research also suggests that sleep and circadian rhythms are regulated differently between women and men. However, does sleep and circadian rhythms regulation age similarly in men and women? In this review, we present the mechanisms underlying age-related differences in sleep and the current state of knowledge on how they interact with sex. We also address how testosterone, estrogens, and progesterone fluctuations across adulthood interact with sleep and circadian regulation. Finally, we will propose research avenues to unravel the mechanisms underlying sex differences in age-related effects on sleep.

Sex differences in associations of arginine vasopressin and oxytocin with resting-state functional brain connectivity.

Oxytocin (OT) and arginine vasopressin (AVP) exert robust and sexually dimorphic influences on cognition and emotion. How these hormones regulate relevant functional brain systems is not well understood. OT and AVP serum concentrations were assayed in 60 healthy individuals (36 women). Brain functional networks assessed with resting-state functional magnetic resonance imaging (rs-fMRI) were constructed with graph theory-based approaches that characterize brain networks as connected nodes. Sex differences were demonstrated in rs-fMRI. Men showed higher nodal degree (connectedness) and efficiency (information propagation capacity) in left inferior frontal gyrus (IFG) and bilateral superior temporal gyrus (STG) and higher nodal degree in left rolandic operculum. Women showed higher nodal betweenness (being part of paths between nodes) in right putamen and left inferior parietal gyrus (IPG). Higher hormone levels were associated with less intrinsic connectivity. In men, higher AVP was associated with lower nodal degree and efficiency in left IFG (pars orbitalis) and left STG and less efficiency in left IFG (pars triangularis). In women, higher AVP was associated with lower betweenness in left IPG, and higher OT was associated with lower nodal degree in left IFG (pars orbitalis). Hormones differentially correlate with brain networks that are important for emotion processing and cognition in men and women. AVP in men and OT in women may regulate orbital frontal cortex connectivity, which is important in emotion processing. Hormone associations with STG and pars triangularis in men and parietal cortex in women may account for well-established sex differences in verbal and visuospatial abilities, respectively. © 2016 Wiley Periodicals, Inc.

Cortisol reactivity and emotional memory after psychosocial stress in oral contraceptive users.

Oral contraceptive (OC) users typically show a blunted or no cortisol response to psychosocial stress. Although most OC regimens include both an inactive (dummy) and active pill phase, studies have not systematically investigated cortisol responses during these pill phases. Further, high levels of cortisol following a stressor diminish retrieval of emotional material, but the effects of stress on memory among OC users are poorly understood. We examined the effects of a psychosocial stressor, the Trier Social Stress Test, vs. a control condition on cortisol responsivity and emotional memory retrieval in women tested either during their active (n = 18) or inactive pill phase (n = 21). In secondary analyses, we quantitatively compared OC users with normally cycling women and showed a significant lack of cortisol response during both active and inactive pill phase. Emotional recall did not differ between active and inactive pill phases. Stress differentially diminished recall of negative words compared with positive or neutral words, but cortisol levels were unrelated to memory performance. These findings indicate that OC users have distinct cortisol and memory responses to stress that are similar between the active and inactive pill phases. © 2016 Wiley Periodicals, Inc.

Evidence of association between sleep quality and APOE ε4 in healthy older adults: A pilot study.

BACKGROUND: It has been estimated that the prevalence of Alzheimer disease (AD) and related dementias will triple by 2035, unless effective interventions or treatments are found for the neurodegenerative disease. Understanding sleep changes as a marker for both AD risk and progression is a burgeoning area of investigation. Specifically, there is emerging evidence that both sleep disturbances and the APOE ε4 allele are associated with increased dementia risk. Previous research has suggested that in AD, individuals carrying the APOE ε4 allele have decreased sleep quality compared to individuals without the APOE ε4 allele. This observational trial aimed to determine if healthy older adults with the risk allele (APOE ε4+) have more sleep complaints or evidence of objective sleep disruption compared to healthy older adults without the risk allele (APOE ε4-). METHODS: Within the larger Brain in Motion study, a subset of participants completed at-home polysomnography (PSG) and actigraphy sleep assessment. Subjective sleep complaints were determined using the Pittsburgh Sleep Quality Index. RESULTS: This investigation found a significant relationship between presence of APOE ε4 allele and objective sleep disturbances measured by both actigraphy and PSG, but not subjective sleep complaints in a healthy population screened for dementia. CONCLUSIONS: These data suggest that the influence of APOE ε4 allele on objective sleep quality may precede subjective sleep complaints in individuals at increased risk for dementia.

Stellate ganglion blockade and verbal memory in midlife women: Evidence from a randomized trial.

OBJECTIVES: In a pilot randomized clinical trial of active stellate ganglion blockade (SGB) versus sham control, SGB significantly reduced the frequency of reported moderate to severe vasomotor symptoms (VMS) and the frequency of physiologic VMS measured using ambulatory skin conductance monitors. Here we examine secondary effects of SGB on verbal learning and memory. STUDY DESIGN: In a randomized, sham-controlled study, 36 women met eligibility criteria for cognitive assessments, of whom 17 were randomized to receive fluoroscopy-guided SGB and 19 to sham control. MAIN OUTCOME MEASURES: At baseline and three months post-treatment, women completed tests of verbal learning and memory (primary outcome) and other cognitive measures and also wore an ambulatory monitor for 24h to measure physiologic VMS and VMS reported in real time. RESULTS: Verbal learning improved following active SGB (p<0.05) but not sham treatment; however, the interaction between group and time was not significant (p values 0.13-0.20). Two secondary cognitive measures improved only in the sham group. Improvements in physiologic VMS correlated significantly with improvements in verbal learning (r=0.51, p<0.05). CONCLUSIONS: SGB might confer benefits to memory in relation to the magnitude of improvement in physiologic VMS. Broadly these findings suggest a possible link between physiologic VMS and memory problems in midlife women.

Promoting brain health through exercise and diet in older adults: a physiological perspective.

The rise in incidence of age-related cognitive impairment is a global health concern. Ageing is associated with a number of changes in the brain that, collectively, contribute to the declines in cognitive function observed in older adults. Structurally, the ageing brain atrophies as white and grey matter volumes decrease. Oxidative stress and inflammation promote endothelial dysfunction thereby hampering cerebral perfusion and thus delivery of energy substrates and nutrients. Further, the development of amyloid plaques and neurofibrillary tangles contributes to neuronal loss. Of interest, there are substantial inter-individual differences in the degree to which these physical and functional changes impact upon cognitive function as we grow older. This review describes how engaging in physical activity and cognitive activities and adhering to a Mediterranean style diet promote 'brain health'. From a physiological perspective, we discuss the effects of these modifiable lifestyle behaviours on the brain, and how some recent human trials are beginning to show some promise as to the effectiveness of lifestyle behaviours in combating cognitive impairment. Moreover, we propose that these lifestyle behaviours, through numerous mechanisms, serve to increase brain, cerebrovascular and cognitive reserve, thereby preserving and enhancing cognitive function for longer.

Registry-based randomized controlled trials- what are the advantages, challenges, and areas for future research?

Registry-based randomized controlled trials are defined as pragmatic trials that use registries as a platform for case records, data collection, randomization, and follow-up. Recently, the application of registry-based randomized controlled trials has attracted increasing attention in health research to address comparative effectiveness research questions in real-world settings, mainly due to their low cost, enhanced generalizability of findings, rapid consecutive enrollment, and the potential completeness of follow-up for the reference population, when compared with conventional randomized effectiveness trials. However several challenges of registry-based randomized controlled trials have to be taken into consideration, including registry data quality, ethical issues, and methodological challenges. In this article, we summarize the advantages, challenges, and areas for future research related to registry-based randomized controlled trials.

Sex and diagnosis specific associations between DNA methylation of the oxytocin receptor gene with emotion processing and temporal-limbic and prefrontal brain volumes in psychotic disorders.

BACKGROUND: The oxytocin (OT) system, including receptor epigenetic mechanisms, has been shown to influence emotion processing, especially in females. Whether OT receptor (OXTR) epigenetic alterations occur across psychotic disorders in relation to illness-related disturbances in social cognition and brain anatomy is unknown. METHODS: Participants with affective and nonaffective psychotic disorders (92 women, 75 men) and healthy controls (38 women, 37 men) from the Chicago site of the BSNIP study completed the Penn Emotion Recognition Test (ER-40), a facial emotion recognition task. We measured cytosine methylation at site -934 upstream of the OXTR start codon in DNA from whole blood, and for the first time their relationship with plasma OT levels assessed by enzyme-immunoassay. Volumes of brain regions supporting social cognition were measured from MRI scans using FreeSurfer. RESULTS: Patients with prototypic schizophrenia features showed higher levels of DNA methylation than those with prototypic bipolar features. Methylation was higher in women than men, and was associated with poorer emotion recognition only in female patients and controls. Greater methylation was associated with smaller volumes in temporal-limbic and prefrontal regions associated previously with social cognition, but only in healthy women and females with schizophrenia. CONCLUSION: DNA methylation of the OXTR site -934 was higher in schizophrenia spectrum than bipolar patients. Among patients, it was linked to behavioral deficits in social cognition and neuroanatomic structures known to support emotion processing only in schizophrenia spectrum individuals.

The Attention Network Test-Interaction (ANT-I): reliability and validity in healthy older adults.

The Attention Network Test (ANT) is a frequently used computer-based tool for measuring the three attention networks (alerting, orienting, and executive control). We examined the psychometric properties of performance on a variant of the ANT, the Attention Network Test-Interaction (ANT-I) in healthy older adults (N = 173; mean age = 65.4, SD = 6.5; obtained from the Brain in Motion Study, Tyndall et al. BMC Geriatr 13:21, 2013. doi: 10.1186/1471-2318-13-21) to evaluate its usefulness as a measurement tool in both aging and clinical research. In terms of test reliability, split-half correlation analyses showed that all network scores were significantly reliable, although the strength of the correlations varied across networks as seen before (r = 0.29, 0.70, and 0.68, for alerting, orienting, and executive networks, respectively, p's < 0.05). In terms of construct validity, ANOVAs confirmed that each network score was significant (18.3, 59.4, and 109.2 ms for the alerting, orienting, and executive networks, respectively, p's < 0.01) and that these scores were generally independent from each other. Importantly, for criterion validity, a series of hierarchical linear regressions showed that the executive network score, in addition to demographic information, was a significant predictor of performance on tests of conflict resolution as well as verbal memory and retrieval (ß = -0.165 and -0.184, p's < 0.05, respectively). These results provide new information regarding the reliability and validity of ANT-I test performance in a healthy older adult population. The results provide insights into the psychometrics of the ANT-I and its potential utility in clinical research settings.

Association between Lifetime Physical Activity and Cognitive Functioning in Middle-Aged and Older Community Dwelling Adults: Results from the Brain in Motion Study.

To determine if total lifetime physical activity (PA) is associated with better cognitive functioning with aging and if cerebrovascular function mediates this association. A sample of 226 (52.2% female) community dwelling middle-aged and older adults (66.5 ± 6.4 years) in the Brain in Motion Study, completed the Lifetime Total Physical Activity Questionnaire and underwent neuropsychological and cerebrovascular blood flow testing. Multiple robust linear regressions were used to model the associations between lifetime PA and global cognition after adjusting for age, sex, North American Adult Reading Test results (i.e., an estimate of premorbid intellectual ability), maximal aerobic capacity, body mass index and interactions between age, sex, and lifetime PA. Mediation analysis assessed the effect of cerebrovascular measures on the association between lifetime PA and global cognition. Post hoc analyses assessed past year PA and current fitness levels relation to global cognition and cerebrovascular measures. Better global cognitive performance was associated with higher lifetime PA (p=.045), recreational PA (p=.021), and vigorous intensity PA (p=.004), PA between the ages of 0 and 20 years (p=.036), and between the ages of 21 and 35 years (p.5), but partially mediated the relation between current fitness and global cognition. This study revealed significant associations between higher levels of PA (i.e., total lifetime, recreational, vigorous PA, and past year) and better cognitive function in later life. Current fitness levels relation to cognitive function may be partially mediated through current cerebrovascular function.