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.

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).

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.

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.