Evaluating Recovery After Two and Three Repeated Concussions Using Growth Curves.

The results of prior research concerning the effects of repeated concussions have been mixed. The aim of this study was to evaluate how concussion outcomes and presentation changed within patients who were evaluated at a concussion specialty clinic multiple times with a concussion. Subjects included 202 patients (54% male) aged 10-21 years (M = 13.17) who presented to a specialty concussion clinic for two and three concussions (77% sport-related) and were followed through formal clearance. First, growth curve models were estimated to determine recovery time and initial symptom burden across the multiple injuries. Second, covariates were added to these models to evaluate which demographic, risk factor, or injury variables predicted any change that did occur in evaluation or outcome variables. Models indicated that each subsequent concussion linearly resulted in significantly fewer days to recovery (-4.62 days, p < 0.047) across three concussions, and significantly lower (and linear) symptom scores on the post-concussion symptom scale (PCSS) (-2.16, p = 0.05). More severe presentation (i.e., days to recovery; higher symptom score) was significantly associated (-.62, p = 0.005) with greater improvement in recovery time (-.62, p = 0.005) and symptom burden (-.56, p < 0.001) at subsequent injuries. No covariates were significantly associated with improvement (or lack thereof) at subsequent injuries. This study adds to evidence suggesting multiple injuries is not associated with protracted recovery at subsequent injuries, in the context of treatment and full clearance for each injury at a multi-disciplinary clinic.

Incidence of concussion and associated risk factors in collegiate soccer: findings from the NCAA-DoD CARE consortium.

This retrospective cohort study aims to examine concussion incidence rates (IR) in collegiate soccer players and compare IRs based on risk factors including sex, competition level, games/practices, history of concussion, and playing position. Collegiate soccer players were recruited (n = 2,471) from 23 institutions from the NCAA-DoD Concussion Assessment, Research, and Education (CARE) Consortium. Incidence rates for concussion per 1000 athlete exposures (AEs) were calculated across the 2015-16/2016-17 seasons. Incidence rates (IR) comparing risk factor groups were also calculated. A total of 162 concussions occurred during the study, for an IR of 0.08/1000 AEs. Females were more likely to have a concussion than males overall (IR = 1.47) and were more likely to have a concussion in games (IR = 1.42) and practices (IR = 2.91). Concussions were more likely during competition compared to practice (IR = 2.53), and less likely in Division III, compared to Divisions I and II, χ2 = 6.5, p > .05. In the concussed group, male sex was associated with 2.47 times higher odds of playing defender and 2.29 times higher odds of a collision mechanism. Results confirm previous findings that females and game exposures have higher concussion IR than males and practice exposures. Findings also supported sex differences in IRs based on exposure type, position, and mechanism.

Evidence for a multidomain clinical assessment of mild traumatic brain injury in older adults.

BACKGROUND: There are few guidelines on the appropriate clinical tools to evaluate mTBI in older adults. OBJECTIVE: We aimed to investigate the utility of a multidomain assessment to differentiate older adults with mTBI from controls. METHODS: Participants included 68 older adults (37% male) aged 60-76 (M = 66.24, SD = 4.50) years. Thirty-four patients were diagnosed with a mTBI at a specialty mTBI clinic within 90 days of injury, and age- and sex-matched to 34 community controls. Participants completed the following assessments: Post-Concussion Symptom Scale (PCSS), Short Fall Efficacy Scale-International (Short FES-I), Generalized Anxiety Disorder-7 Item Scale (GAD-7), Geriatric Depression Scale-5 Item (GDS-5), Wide Range Achievement Test-Fourth Edition (WRAT-4) reading subtest, subtests of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), clock drawing, and Vestibular/Ocular Motor Screening for Concussion (VOMS). Independent-samples t-tests or chi-squared analyses were used to compare assessment results between groups. A logistic regression (LR) was conducted to determine which combination of assessments best identified the mTBI group from controls. RESULTS: The mTBI group endorsed significantly more symptoms of concussion (p < .001), balance concerns (p < .001), anxiety (p < .001), and depression (p = 0.04), and performed worse on cognitive (p < .001), vestibular (p < .001), and oculomotor (p = .004) screening relative to controls. The LR (p < .001; r2 = 0.90) correctly identified 98.5% of older adults and retained concussion (p = .01) and depression (p = .02) symptoms, and cognitive (p = .03) and vestibular (p = .04) screening in the final model. DISCUSSION: The current findings support a multidomain assessment model of care for evaluating mTBI in older adults.

The Effects of Rest on Concussion Symptom Resolution and Recovery Time: A Meta-analytic Review and Subgroup Analysis of 4329 Patients.

BACKGROUND: Numerous individual studies suggest that rest may have a negative effect on outcomes following concussion. PURPOSE: To perform a systematic meta-analysis of the effects of prescribed rest compared with active interventions after concussion. STUDY DESIGN: Meta-analysis; Level of evidence, 4. METHODS: A meta-analysis (using the Hedges g) of randomized controlled trials and cohort studies was conducted to evaluate the effects of prescribed rest on symptoms and recovery time after concussion. Subgroup analyses were performed for methodological, study, and sample characteristics. Data sources were obtained from systematic search of key terms using Ovid Medline, Embase, Cochrane Database of Systematic Reviews, APA PsycINFO, Web of Science, SPORTDiscus, and ProQuest dissertations and theses through May 28, 2021. Eligible studies were those that (1) assessed concussion or mild traumatic brain injury; (2) included symptoms or days to recovery for ≥2 time points; (3) included 2 groups with 1 group assigned to rest; and (4) were written in the English language. RESULTS: In total, 19 studies involving 4239 participants met criteria. Prescribed rest had a significant negative effect on symptoms (k = 15; g = -0.27; SE = 0.11; 95% CI, -0.48 to -0.05; P = .04) but not on recovery time (k = 8; g = -0.16; SE = 0.21; 95% CI, -0.57 to 0.26; P = .03). Subgroup analyses suggested that studies with shorter duration (<28 days) (g = -0.46; k = 5), studies involving youth (g = -0.33; k = 12), and studies focused on sport-related concussion (g = -0.38; k = 8) reported higher effect sizes. CONCLUSION: The findings support a small negative effect for prescribed rest on symptoms after concussion. Younger age and sport-related mechanisms of injury were associated with a greater negative effect size. However, the lack of support for an effect for recovery time and the relatively small overall numbers of eligible studies highlight ongoing concerns regarding the quantity and rigor of clinical trials in concussion. REGISTRATION: CRD42021253060 (PROSPERO).

Multidomain concussion symptoms in adolescents: A network analysis.

Concussion is a heterogeneous injury involving symptoms and impairment that represent multiple domains (e.g., anxiety, cognitive, vestibular). Network analysis, a modeling technique that estimates relationships among symptoms, provides a statistically sound and clinically practical method for evaluating these interrelationships. The purpose of this study was to examine, using network analysis, relationships among clinical assessments and multidomain symptom report within a sample of adolescent patients following a concussion. Participants included 326 patients (49.7% female) aged 10-21 years presenting to a concussion specialty clinic within 28 days of a diagnosed concussion. Participants completed the Post-Concussion Symptom Scale (PCSS) and Vestibular-Ocular Motor Screening (VOMS) tool at initial visit. Network models were applied to PCSS symptoms initially, and then applied to VOMS and PCSS symptom data together. Dizziness (Expected influence (EI) = 1.10) and sadness (EI = 1.91) were most central (i.e., highest cumulative partial correlations) to the symptom network. Numerous interdomain relationships were supported, including irritability with mental fogginess (edgeweight = 0.12), dizziness with headache (edgeweight = 0.16), and dizziness with vision problems (edgeweight = 0.13). Community analyses resulted in VOMS groupings by domain (e.g., vestibular) and symptom (e.g., dizziness). The findings suggest a more direct focus on symptom interrelationships, such as how dizziness contributes to emotional symptoms, may help guide and better target treatments. Also, results suggest grouping VOMS assessment by symptom (e.g., dizziness) and item (e.g., vestibular-ocular reflex) may better reflect underlying impairments reflected by these symptom-item combinations.

Association of Multidomain Assessment Outcomes With Referral for Vestibular Therapy After Concussion.

CONTEXT: Multiple aspects of a multidomain assessment have been validated for identifying concussion; however, researchers have yet to determine which components are related to referral for vestibular therapy. OBJECTIVE: To identify which variables from a multidomain assessment were associated with receiving a referral for vestibular therapy after a concussion. DESIGN: Retrospective chart review, level of evidence 3. PATIENTS OR OTHER PARTICIPANTS: Participants (n = 331; age = 16.9 ± 7.2 years; 39.3% female) were diagnosed with a concussion per international consensus criteria by a clinical neuropsychologist after presenting to a concussion specialty clinic. MAIN OUTCOME MEASURE(S): Medical chart data were extracted from the first clinical visit regarding preinjury medical history, computerized neurocognition, Post-Concussion Symptom Scale, Concussion Clinical Profiles Screen, and Vestibular Ocular Motor Screening within 16.2 ± 46.7 days of injury. We built 5 backwards logistic regression models to associate the outcomes from each of the 5 assessments with referral for vestibular therapy. A final logistic regression model was generated using variables retained in the previous 5 models as potential predictors of referral for vestibular therapy. RESULTS: The 5 models built from individual components of the multidomain assessment predicted referral for vestibular therapy (R2 = 0.01-0.28) with 1 to 6 statistically significant variables. The final multivariate model (R2 = 0.40) retained 9 significant variables, represented by each of the 5 multidomain assessments except neurocognition. Variables that had the strongest association with vestibular therapy referral were motor vehicle accident mechanism of injury (odds ratio [OR] = 15.45), migraine history (OR = 3.25), increased headache when concentrating (OR = 1.81), and horizontal vestibular ocular reflex (OR = 1.63). CONCLUSIONS: We demonstrated the utility of a multidomain assessment and identified outcomes associated with a referral for vestibular therapy after a concussion.

Characteristics of concussion subtypes from a multidomain assessment.

OBJECTIVE: The aim of this study was to analyze the best combination of clinical variables associated with concussion subtypes using a multidomain assessment comprising medical history; symptoms; and cognitive, ocular, and vestibular impairment in a cohort of patients presenting to a concussion specialty clinic. METHODS: Adolescent patients (n = 293) completed demographics and medical history, Concussion Clinical Profiles Screening, Immediate Post-Concussion Assessment and Cognitive Testing, and vestibular ocular motor screening at their first visit (mean 7.6 ± 7.8 days postinjury) to a concussion specialty clinic. Each participant was adjudicated to have one or more subtype (anxiety/mood, cognitive, migraine, ocular, and vestibular) by a healthcare professional based on previously published criteria. A series of backward, stepwise logistic regressions were used to identify significant predictors of concussion subtypes, and predictive probabilities from the logistic regression models were entered into area under the receiver operating characteristic curve (AUC) models. RESULTS: Each of 5 logistic regression models predicting primary subtypes accounted for 28%-50% of the variance (R2 = 0.28-0.50, p < 0.001) and included 2-8 significant predictors per model. Each of the models significantly differentiated the primary subtype from all other subtypes (AUC = 0.76-0.94, p < 0.001). CONCLUSIONS: These findings suggest that each concussion subtype can be identified using specific outcomes from a multidomain assessment. Clinicians can employ such an approach to better identify and monitor recovery from subtypes as well as guide interventions.

Improved post-injury cognitive test results: examining invalid baseline ImPACT testing.

OBJECTIVE: Evidence suggests that Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) validity thresholds may not be adequately sensitive to baseline performances that are not representative of an athlete's full, uninjured cognitive abilities. The true prevalence of this occurrence is unknown. This study used improvement on post-injury testing (i.e., better performance after the athlete has been removed from play due to suspected concussion than at baseline) to assess the frequency of unrepresentative baseline ImPACT assessments. METHOD: Post-injury ImPACT assessments by NCAA athletes with preceding baseline performance that was considered valid using traditional indices were included. Published reliable change indices (RCI) identified acute post-injury composite scores that improved from baseline. RESULTS: Of 155 post-injury assessments, 68 (43.9%) exhibited reliable improvement from baseline on at least 1 composite score, even after excluding persons with invalid protocols. CONCLUSIONS: Prevalence of ImPACT unrepresentative baseline ImPACT performances may be higher than previously estimated, and many individuals may not be detected by current validity indices. Further research is needed to refine assessment and promote player safety.

Temporal Differences in Concussion Symptom Factors in Adolescents following Sports-Related Concussion.

OBJECTIVE: To evaluate temporal differences in concussion symptoms up to 30 days following a sports-related concussion. STUDY DESIGN: Adolescent and young adult athletes (n = 782) were separated based on time since injury at presentation as Early (0-7 days; n = 321, age: 15.4 ± 1.9 years, 51.7% female), Middle (8-14 days; n = 281, age: 15.8 ± 2.2 years, 54.8% female), and Late (15-30 days; n = 180, age: 15.6 ± 1.8 years, 52.8% female). All participants completed the 22-item Post-Concussion Symptom Scale at first visit. A confirmatory factor analysis was completed separately for each time since injury cohort using a 4-component model reported previously. RESULTS: The confirmatory factor analysis model fit was acceptable for Early, Middle, and Late (using cognitive-migraine-fatigue, affective, sleep, and somatic factors). Both affective (change = 0.30; P = .01; Cohen d = 0.30) and sleep (change = 0.51; P ≤ .001; Cohen d = 0.47) factors were significantly greater in the Late group compared with the Early, but not Middle, groups. The previously reported 4-factor symptom model, including cognitive-migraine-fatigue, affective, somatic, and sleep factors, was appropriate for adolescents up to 30 days' postinjury. However, adolescents who presented between 15 and 30 days' postinjury reported greater affective and sleep symptoms than those who presented within 1 week. CONCLUSIONS: Clinicians should consider these temporal differences when evaluating concussion symptoms in adolescents, as greater affective and sleep symptoms can be predictive of prolonged recovery/persistent complications.

Concurrent validity of the Vestibular/Ocular Motor Screening (VOMS) tool with the Dizziness Handicap Inventory (DHI) among adolescents with vestibular symptoms/impairment following concussion.

OBJECTIVE: To determine whether the Vestibular/Ocular Motor Screening (VOMS) tool demonstrates concurrent validity with the Dizziness Handicap Inventory (DHI) in a sample of concussed athletes referred for vestibular therapy and whether DHI items were predictive of VOMS outcomes. DESIGN: Cross-sectional cohort study. SETTING: Concussion specialty/vestibular therapy clinic. METHODS: Adolescents (n = 55; 15.4 ± 1.6 years) with diagnosed sport-related concussion (SRC) with vestibular symptoms and/or impairment between October 2018-February 2020. Patients completed VOMS and DHI at initial visit. Seven individual VOMS and twenty-five DHI items, VOMS and DHI total score and three DHI sub-scales, were compared with Spearman correlations. Three backwards linear regression (LR) models were built to predict 1. VOMS vestibular symptoms, 2. VOMS ocular symptoms, and 3. near-point of convergence-distance (NPC-distance) using individual DHI items as predictors. RESULTS: Spearman correlations (p) identified DHI items with moderate to strong associations for VOMS items. DHI sub-scales demonstrated moderate-to-strong correlations with VOMS items (p = 0.30-0.59). Total DHI score demonstrated a moderate-to-strong association with HSAC (p = 0.30), VSAC (p = 0.32), and SP (p = 0.61). Results from the LRs predicting VOMS ocular symptoms (R (Alsalaheen et al., 2010) = 0.56; p < 0.001), and VOMS vestibular symptoms (R (Alsalaheen et al., 2010) = 0.23; p = 0.01), and NPC-distance (R (Alsalaheen et al., 2010) = 0.56; p < 0.001) included significant DHI predictors. CONCLUSIONS: There was moderate-to-strong associations between VOMS and 56% of DHI items (i.e., p > 0.30).

Psychometric evaluation of the Hopkins Rehabilitation Engagement Rating Scale in postacute physical therapy services.

PURPOSE/OBJECTIVE: Evaluate the reliability and validity of the Hopkins Rehabilitation Engagement Scale (HRERS) in a postacute rehabilitation sample. We hypothesized that HRERS items would comprise a single factor, and would demonstrate adequate internal consistency and temporal stability, and significant relationships with key constructs. Research Method and Design: Retrospective medical record review between 2016 and 2017 of older veterans (N = 107) admitted to a community living center postacute care (CLC-PAC) rehabilitation hospital unit to address targeted physical therapy rehabilitation goals. Inclusion criteria included availability of two HRERS administrations at Time 1 (admission) and Time 2 (approximately one-month follow-up or physical therapist/CLC-PAC discharge). RESULTS: Across timepoints, HRERS items reflect a single factor of engagement, and the scale has good internal consistency at admission (Time 1, α = .759) and follow-up (Time 2, α = .877). The temporal stability of HRERS across ratings was r = .56 (p < .001). Increased pain rating (r = -.309, p < .01) and depressive symptoms (-.287, p < .01) at admission correlates with subsequent physical therapist (PT) engagement (HRERS Time 2). Low admission PT engagement correlates with less frequent PT attendance (r = -.242, p < .01) and greater number of consults placed during the CLC stay (r = -.222, p < .05). CONCLUSIONS/IMPLICATIONS: HRERS is a reliable and valid measure of PT engagement in older CLC-PAC Veterans. Findings support the administration of the HRERS at more than one timepoint during rehabilitation to inform interventions targeting select behavioral health factors such as pain and depression. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Randomized Clinical Trial Examining the Impact of Lactobacillus rhamnosus GG Probiotic Supplementation on Cognitive Functioning in Middle-aged and Older Adults.

PURPOSE: The gut microbiome has been linked to cognitive function and appears to worsen with aging. Probiotic supplementation has been found to improve the health of the gut microbiome. As such, it is possible that probiotic supplementation may protect the aging brain. The current study examined the cognitive benefits of probiotic supplementation (Lactobacillus rhamnosus GG) in healthy middle-aged and older adults. MATERIALS AND METHODS: The study was a double-blind, placebo-controlled, randomized clinical trial. Two hundred community-dwelling adults aged 52-75 were enrolled (mean age=64.3, SD=5.52). A three-month intervention involved daily consumption of probiotic or placebo. Independent sample t-tests, chi-squared tests, and repeated measure ANOVAs compared groups and examined changes over time. Primary outcome was change in NIH Toolbox Total Cognition Score from baseline to follow-up. RESULTS: A total of 145 participants were examined in primary analyses (probiotic=77, placebo=68) and excluded persons due to discontinuation, low adherence, missing data, or outlier values. Established criteria (ie ≥1 subtest t-scores ≤35; n=19, n=23) were used to operationally define cognitive impairment. Repeated measures ANOVAs revealed that persons with cognitive impairment who consumed probiotics exhibited a greater total cognition score improvement than persons with cognitive impairment in the placebo group and cognitively intact persons in probiotic or placebo groups. CONCLUSION: Lactobacillus rhamnosus GG probiotic supplementation was associated with improved cognitive performance in middle-aged and older adults with cognitive impairment. Probiotic supplementation may be a novel method for protecting cognitive health in aging.

Novel ImPACT validity indices in collegiate student-athletes with and without histories of ADHD or academic difficulties.

Objective: Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) assesses neurocognitive functioning in sports-related concussion. Previous work demonstrates ImPACT's validity indices detect poor effort at disproportionately higher rates in athletes with histories of attention deficit hyperactivity disorder (ADHD) or academic difficulties. The present study examines whether previously suggested 'dormant' validity indices, Word Memory Correct Distractors (WMCD), and Design Memory Correct Distractors (DMCD), reduce disproportionate invalidity in collegiate athletes with such histories.Method: Six seasons of ImPACT protocols were examined (n = 1727). Athletes were grouped by self-reported histories of ADHD, academic difficulties, or comorbid ADHD and academic difficulties. Chi-square analyses compared invalidity rates using existing validity indices and both standard and conservative cutoffs for WMCD and DMCD.Results: Using standard cutoffs for dormant indices (WMCD < 22, DMCD < 16) produced significant differences in rates of athletes identified as having an invalid protocol, with the comorbid group exhibiting the highest invalidity rate (63.2%) and the no history group producing the lowest (42.0%), χ2 (3) = 11.57, p < .01, Cramer's V = 0.08. This difference remained when utilizing conservative cutoffs (WMCD < 18, DMCD < 10), with the comorbid group again producing the highest (26.3%) and the no history group producing the lowest (10.4%), χ2 (3) = 15.64, p < .005, Cramer's V = 0.10.Conclusions: Student-athletes with self-reported histories of ADHD and academic difficulties are more likely to produce invalid protocols, even with dormant indices. These findings emphasize the difficulty in assessing validity in special populations of athletes and encourage further work in this area.

A randomized clinical trial examining the impact of LGG probiotic supplementation on psychological status in middle-aged and older adults.

Cognitive decline is common in older adults and more than 5 million Americans suffer from Alzheimer's disease (AD). A number of physiological processes including systemic inflammation, excess adiposity, and impaired glucoregulation arise from a combination of genetic and behavioral factors and increase risk for developing AD or other forms of dementia. Recent research suggests that the gut microbiome may moderate these pathological processes and possibly influence cognitive outcomes. This paper reviews the methodology for a double-blind, randomized clinical trial examining the influence of Lactobacillus GG (LGG) probiotic supplementation on mood and cognitive functioning in middle-aged and older adults. Our two primary hypotheses include: 1) Participants randomized to the probiotic group will show greater improvements in psychological status compared to participants in the placebo group; 2) Participants randomized to the probiotic group will show greater improvements in executive functioning and processing speed, as evidenced through performance on neuropsychological testing, than participants in the placebo group. We anticipate these results will inform future efforts on the feasibility of LGG probiotic supplementation as an intervention for psychological status and cognitive functioning and further elucidate the link between the gut microbiome and cognitive health.

Collegiate Student Athletes With History of ADHD or Academic Difficulties Are More Likely to Produce an Invalid Protocol on Baseline ImPACT Testing.

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) and other academically-relevant diagnoses have been suggested as modifiers of neurocognitive testing in sport-related concussion, such as Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). These preexisting conditions may suppress ImPACT scores to the extent that they are indistinguishable from low scores because of poor effort. The present study hypothesized that student athletes with history of ADHD or academic difficulties produce lower ImPACT composite scores and are more likely to produce invalid protocols than those without such conditions. DESIGN: Cross-sectional study. SETTING: Midsized public university. PARTICIPANTS: Nine hundred forty-nine National College Athletic Association athletes (average age = 19.2 years; 6.8% ADHD, 5.6% Academic Difficulties, 2.0% comorbid ADHD/Academic Difficulties). INDEPENDENT VARIABLES: Three seasons of baseline ImPACT protocols were analyzed. Student athletes were grouped using self-reported histories of ADHD or academic difficulties taken from ImPACT demographic questions. DEPENDENT VARIABLES: ImPACT composite scores and protocol validity. RESULTS: Student athletes in the academic difficulties and comorbid groups performed worse on ImPACT composite scores (Pillai's Trace = 0.05), though this pattern did not emerge for those with ADHD. Student athletes with comorbid history were more likely to produce an invalid baseline (10.5% invalid) (χ (2) = 11.08, P = 0.004). Those with ADHD were also more likely to produce an invalid protocol (7.7% invalid, compared with 2.6% in student athletes with no history) (χ (2) = 10.70, P = 0.005). CONCLUSIONS: These findings suggest that student athletes reporting comorbid histories or histories of academic difficulties alone produce lower ImPACT composite scores, and that those with comorbid histories or histories of ADHD alone produce invalid protocol warnings more frequently than student athletes without such histories. Future studies should further examine invalid score thresholds on the ImPACT, especially in student athletes with conditions that may influence test performance. CLINICAL RELEVANCE: Student athletes with history of ADHD or academic difficulties may more frequently fall below validity score thresholds, suggesting caution in interpreting test performance.

A preliminary examination of gut microbiota, sleep, and cognitive flexibility in healthy older adults.

OBJECTIVES: Inadequate sleep increases the risk for age-related cognitive decline and recent work suggests a possible role of the gut microbiota in this phenomenon. Partial sleep deprivation alters the human gut microbiome, and its composition is associated with cognitive flexibility in animal models. Given these findings, we examined the possible relationship among the gut microbiome, sleep quality, and cognitive flexibility in a sample of healthy older adults. METHODS: Thirty-seven participants (age 64.59 ± 7.54 years) provided a stool sample for gut microbial sequencing and completed the Pittsburgh Sleep Quality Index and Stroop Color Word Test as part of a larger project. RESULTS: Better sleep quality was associated with better Stroop performance and higher proportions of the gut microbial phyla Verrucomicrobia and Lentisphaerae. Stroop Word and Color-Word performance correlated with higher proportions of Verrucomicrobia and Lentisphaerae. Partial correlations suggested that the relationship between Lentisphaerae and Stroop Color-Word performance was better accounted for by sleep quality; sleep quality remained a significant predictor of Color-Word performance, independent of the Lentisphaerae proportion, while the relationship between Lentisphaerae and Stroop performance was non-significant. Verrucomicrobia and sleep quality were not associated with Stroop Word performance independent of one another. CONCLUSIONS: The current findings suggest a possible relationship among sleep quality, composition of the gut microbiome, and cognitive flexibility in healthy older adults. Prospective and experimental studies are needed to confirm these findings and determine whether improving microbiome health may buffer against sleep-related cognitive decline in older adults.

Preliminary Evidence for an Association Between the Composition of the Gut Microbiome and Cognitive Function in Neurologically Healthy Older Adults.

OBJECTIVES: Dysbiosis of the gut microbiome is implicated in numerous human health conditions. Animal studies have linked microbiome disruption to changes in cognitive functioning, although no study has examined this possibility in neurologically healthy older adults. METHODS: Participants were 43 community-dwelling older adults (50-85 years) that completed a brief cognitive test battery and provided stool samples for gut microbiome sequencing. Participants performing≥1 SD below normative performance on two or more tests were compared to persons with one or fewer impaired scores. RESULTS: Mann Whitney U tests revealed different distributions of Bacteroidetes (p=.01), Firmicutes (p=.02), Proteobacteria (p=.04), and Verrucomicrobia (p=.003) between Intact and Impaired groups. These phyla were significantly correlated with cognitive test performances, particularly Verrucomicrobia and attention/executive function measures. CONCLUSIONS: The current findings suggest that composition of the gut microbiome is associated with cognitive test performance in neurologically healthy older adults. Future studies are needed to confirm these findings and explore possible mechanisms. (JINS, 2017, 23, 700-705).

Liver Fibrosis Predicts Cognitive Function Following Bariatric Surgery: A Preliminary Investigation.

OBJECTIVE: Obesity is a well-established risk factor for poor neurological outcomes, and bariatric surgery has been shown to improve many aspects of cognitive function. Factors underlying improved cognition following surgery are not yet fully established. A recent study of bariatric surgery patients demonstrated lower preoperative alkaline phosphatase concentrations were linked to greater postoperative cognitive improvement, but this link has not been examined via liver biopsy. The current study examined postoperative cognitive function in individuals with and without fibrosis at the time of bariatric surgery. It expected that those with fibrosis would demonstrate poorer postoperative cognition. METHODS: Thirty-six bariatric surgery patients underwent routine liver biopsy at the time of surgery and completed cognitive testing 1 month postoperatively. RESULTS: Bariatric surgery patients with fibrosis demonstrated poorer performance on a task of executive function (maze errors, P = 0.01) and verbal memory (recognition memory, P = 0.01). CONCLUSIONS: Bariatric surgery patients with fibrosis demonstrated poorer cognition following surgery, providing further evidence for the connection between liver disease and cognitive function. Future work examining mechanisms underlying bariatric postoperative cognitive changes should include examination of broader metabolic functions, particularly liver function.