Dispersal stabilizes coupled ecological and evolutionary dynamics in a host-parasitoid system.

When ecological and evolutionary dynamics occur on comparable timescales, persistence of the ensuing eco-evolutionary dynamics requires both ecological and evolutionary stability. This unites key questions in ecology and evolution: How do species coexist, and what maintains genetic variation in a population? In this work, we investigated a host-parasitoid system in which pea aphid hosts rapidly evolve resistance to Aphidius ervi parasitoids. Field data and mathematical simulations showed that heterogeneity in parasitoid dispersal can generate variation in parasitism-mediated selection on hosts through time and space. Experiments showed how evolutionary trade-offs plus moderate host dispersal across this selection mosaic cause host-parasitoid coexistence and maintenance of genetic variation in host resistance. Our results show how dispersal can stabilize both the ecological and evolutionary components of eco-evolutionary dynamics.

Lower post-injury psychological resilience is associated with increased recovery time and symptom burden following sport-related concussion.

The purpose of this study was to compare athletes with high and low resilience scores on concussion outcomes, and identify significant predictors associated with protracted recovery (>30 days). Forty-five adolescent and young adult athletes (28 males; aged 15.13 ± 2.74; range of 11-22) were diagnosed with an SRC within 14 days of injury (M = 4.9 days) and grouped as high or low resilience based on score on the Connor-Davidson Resilience Scale-10 (CD-RISC-10). Primary dependent measures included days to full clearance, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Depression Anxiety and Stress Scale-21 (DASS-21), and Vestibular/Ocular Motor Screening (VOMS). The low resilience group (n = 22) had a longer recovery (36.0 ± 27.6 vs 17.8 ± 11.2 days), endorsed more mood symptoms (PCSS Affective cluster; 3.8 ± 0.8 vs 0.9 ± 0.7), and were more likely to have VOMS scores above cut off (p = 0.01-0.02), compared to those with high psychological resilience (n = 23). Logistic regression found low resilience scores was the only significant predictor for protracted recovery among injury characteristics and risk factors. Psychological resilience is a critical factor associated with recovery time following sport-related concussions. Low resilience was also associated with other poor clinical outcomes, greater subjective symptom report, more severe vestibular dysfunction, and elevated levels of mood symptoms following injury.

Performance Validity Testing in Patients Presenting to a Specialty Clinic With a Mild Traumatic Brain Injury.

OBJECTIVE: To evaluate predictors of performance validity testing (PVT) and clinical outcome in patients presenting to a specialty clinic with a mild traumatic brain injury (mTBI). SETTING: An outpatient mTBI specialty clinic. PARTICIPANTS: Seventy-six (47% female) patients aged 16 to 66 (mean = 40.58, SD = 14.18) years within 3 to 433 days (mean = 30.63, SD = 54.88, median = 17.00) of a suspected mTBI between 2018 and 2019. DESIGN: A cross-sectional, observational study comparing patients who passed PVT (n = 43) with those who failed (n = 33). A logistic regression (LR) was conducted to evaluate factors that predicted failed PVT. Independent-samples t tests and general linear model were used to evaluate PVT groups on clinical outcomes. The LR with a receiver operating characteristic (ROC) curve was conducted to evaluate embedded validity indicators. MAIN MEASURES: Performance validity testing, computerized neurocognitive testing, vestibular/oculomotor screening, symptom reports. RESULTS: At their initial clinic visit 43% of patients failed PVT. PVT failure was predicted by presence of secondary gain (odds ratio [OR] = 8.11, P = .02), while a history of mental health predicted passing of PVT (OR = 0.29, P = .08). Those who failed PVT performed significantly worse on computerized neurocognitive testing (P < .05) and took an average of 33 days longer to return to work (P = .02). There was no significant difference (P = .20) in recovery time between failed/passed PVT groups when covarying for those who sustained a work injury. Word memory learning percentage less than 69% and design memory learning percentage less than 50% accurately classified patients who failed PVT (area under the ROC curve = 0.74; P < .001). CONCLUSION: Secondary gain was the best predictor of failed PVT. Patients presenting for mTBI evaluation and rehabilitation who fail PVT demonstrate worse performance on cognitive testing and take longer to return to work post-injury, but recover in a similar time frame compared with those who pass PVT. Clinicians should be cautious in discounting patients who yield invalid test results, as these patients appear to be able to achieve recovery in a treatment setting.

The relationship between accelerometer-measured sleep and next day ecological momentary assessment symptom report during sport-related concussion recovery.

OBJECTIVES: Research examining sleep and concussion symptoms following sport-related concussion (SRC) is limited by retrospective self-report rather than objective data from wearable technology and real-time symptom report. The purpose of this study is to use actigraphy and ecological momentary assessment (EMA) to examine the relationship between sleep parameters and next day symptoms. METHODS: Seventeen athletes (47.1%F) aged 12-19 (15.35+/-2.09) years (<72 hours post-SRC) wore Actigraph GT3x+ to measure nighttime sleep and completed post-concussion symptom scales (PCSS) three times via mobile EMA, resulting in a range of 91-177 observations for each outcome. Generalized linear mixed models, utilizing independent variables of sleep efficiency (SE%: ratio of awake time to sleep time) and total sleep time (TST) examined the associations between nightly sleep and symptoms next-day and throughout recovery. RESULTS: SE% (IRR .97, 95%CI: .95, .99, P= .009) and TST (IRR .91, 95%CI: .84, .999, P = .047) were negatively associated with next day night symptoms. The negative relationship between SE% and the cognitive-migraine-fatigue (CMF) factor was significant for next day/night symptoms (P = .01), while TST was associated with symptom severity for the affective symptom factor (P = .015). Sleep was negatively associated with total symptoms and afternoon symptoms in Week 1 and total, morning, afternoon, and night symptoms in Week 2 (ps=.001-.021) of recovery. CONCLUSION: Sleep was negatively associated with symptoms the next day, especially late in the day and among CMF and emotional symptoms. The relationship between sleep and symptom burden was strongest in the subacute stage of concussion recovery, highlighting the potential importance of sleep intervention post-injury.

Influence of Sleep Dysfunction on Concussion Assessment Outcomes Among Adolescent Athletes After Concussion and Healthy Controls.

BACKGROUND: Sleep dysfunction (SD) is associated with a high symptom burden and lower neurocognitive performance after concussion and on baseline testing without injury. However, few studies have compared concussed athletes and controls with and without SD on clinical outcomes. OBJECTIVE: To evaluate differences in clinical outcomes among both concussed athletes and matched controls with and without SD. DESIGN: Retrospective cross-sectional study. PARTICIPANTS: Participants aged 12 to 20 years were recruited from a concussion clinic (n = 50 patients) and research registry/flyers (n = 50 healthy age-/sex-matched controls). Participants were categorized by self-reported SD into one of 4 groups: sport-related concussion (SRC) + SD, SRC only, SD only, and controls. MAIN OUTCOME MEASURES: Post-Concussion Symptom Scale (PCSS), Vestibular/Oculomotor Screening (VOMS), and neurocognitive testing (Immediate Postconcussion Assessment Cognitive Test). RESULTS: Compared with the SRC only group, the SRC + SD group performed worse on all neurocognitive domains, had a higher total symptom score, and endorsed more symptoms on most VOMS items. In addition, the SRC + SD group was at an increased likelihood of having at least 1 abnormal VOMS item compared with SRC only group. The SRC only group had neurocognitive test scores and symptom reports statistically similar to the SD only group. CONCLUSION: Sleep dysfunction after concussion is related to worse neurocognitive performance and higher concussion symptom reporting. This study extended findings to suggest vestibular symptomology is worse among athletes with SD after injury compared to injured athletes without SD. Similar performances on concussion assessments for the SRC only and SD only groups suggest SD may appear similar to clinical presentation of concussion, even at baseline in the absence of SRC.

Utility of 1 Measurement Versus Multiple Measurements of Near Point of Convergence After Concussion.

CONTEXT: Increased near point of convergence (NPC) distance is a common finding after concussion and is associated with physical symptoms and worsened neurocognitive performance. Vestibular/Ocular Motor Screening measures NPC distance across 3 trials and uses the average measurement to inform clinical care. However, whether 3 trials are necessary, are consistent, or add clinical utility is unknown. OBJECTIVE: To investigate the consistency across 3 trials of NPC and establish the classification accuracy (ie, clinical utility) of 1 or 2 trials compared with the standardized average of 3 trials. DESIGN: Retrospective cohort study. SETTING: Sports medicine clinic and research laboratory. PATIENTS OR OTHER PARTICIPANTS: Consecutively enrolled patients aged 10 to 22 years with diagnosed concussions (74% sport related; n = 380). MAIN OUTCOME MEASURE(S): The previously reported clinical cutoff value of ≥5 cm across 3 trials was used. Pearson correlation and intraclass correlation coefficients were used to evaluate agreement between trials and average scores. Reliable change indices (RCIs) using 95% confidence intervals were also calculated. RESULTS: The Pearson correlation (r = .98) and intraclass correlation (0.98) coefficients revealed excellent agreement between the first measurement and average NPC distance across 3 measurements. The RCI across all trials was 2 cm. When the first NPC measurement was ≤3 cm or ≥7 cm, agreement existed within the RCI between the first measurement and the average of 3 measurements in 99.6% of cases. When we averaged the first and second measurements, 379/380 (99.7%) participants had the same classification (ie, <5 cm = normal, ≥5 cm = abnormal) as the average NPC distance across 3 measurements. CONCLUSIONS: Our findings suggest limited utility of multiple or average NPC distance measurements when the initial NPC distance is outside of RCI clinical cutoffs (ie, ≤3 cm or ≥7 cm). Given the high consistency between the first measurement and average NPC distance across 3 trials, only 1 measurement of NPC distance is warranted unless the first measurement is between 3 and 7 cm.

Association of Time Since Injury to the First Clinic Visit With Recovery Following Concussion.

Importance: Recovery after concussion varies, with adolescents taking longer (approximately 30 days) than adults. Many factors have been reported to influence recovery, including preinjury factors, perceptions about recovery, comorbid conditions, and sex. However, 1 factor that may play a role in recovery but has received little attention from researchers is the timeliness of clinical evaluation and care. Objective: To investigate the association of time since injury with initiation of clinical care on recovery time following concussion. Design, Setting, and Participants: This retrospective, cross-sectional study was conducted in a sports medicine clinic between August 2016 and March 2018. Eligible participants were aged 12 to 22 years and had a diagnosed, symptomatic concussion; patients were excluded if recovery data were incomplete. Participants were divided into 2 groups: those seen within 7 days of the injury (early) vs between 8 and 20 days of the injury (late). Data were analyzed between June 2019 and August 2019. Exposures: Time from injury (concussion) to initiation of clinical care. Main Outcomes and Measures: Recovery time; testing with the Post-Concussion Symptom Scale, Immediate Post-Concussion Assessment and Cognitive Testing, and Vestibular/Ocular Motor Screening instruments; demographic factors, medical history, and injury information. Results: A total of 416 individuals were eligible, and 254 (61.1%) were excluded, leaving 162 (38.9%) in analyses. The early group (98 patients) and late group (64 patients) did not differ in age (mean [SD] age, early, 15.3 [1.6] years; late, 15.4 [1.6] years), number of female patients (early, 51 of 98 [52.0%]; late, 40 of 64 [62.5%]), or other demographic, medical history, or injury information. The groups also were similar on symptom severity, cognitive, ocular, and vestibular outcomes at the first clinic visit. Results from a logistical regression supported being in the late group (adjusted odds ratio, 5.8 [95% CI, 1.9-17.6]; P = .001) and visual motion sensitivity symptoms greater than 2 (adjusted odds ratio, 4.5 [95% CI, 1.1-18.0]; P = .04) as factors significantly associated with recovery time. Conclusions and Relevance: Findings suggest that earlier initiation of clinical care is associated with faster recovery after concussion. Other factors may also influence recovery time. Further research is needed to determine the role of active rehabilitation and treatment strategies, as well as demographic factors, medical history, and injury characteristics on the current findings.

A systematic review and meta-analysis of the Test of Memory Malingering in adults: Two decades of deception detection.

Objective: The present study, adhering to Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) guidelines, is the first systematic review and meta-analysis of the Test of Memory Malingering (TOMM) to examine traditional and alternative cutoffs across Trial 1, Trial 2, and Retention.Method: Search criteria identified 539 articles published from 1997 to 2017. After application of selection criteria, 60 articles were retained for meta-analysis. Classification accuracy statistics were calculated using fixed- and random-effects models.Results: For Trial 1, a cutoff of <42 was found to result in the highest sensitivity value (0.59-0.70) when maintaining specificity at ≥0.90. Traditional cutoffs for Trial 2 and Retention were highly specific (0.96-0.98) and moderately sensitive (0.46-0.56) when considering all available studies and only neurocognitive/psychiatric samples classified by known-groups design. For both trials, a modified cutoff of <49 allowed for improved sensitivity (0.59-0.70) while maintaining adequate specificity (0.91-0.97). A supplementary review revealed that traditional TOMM cutoffs produced >0.90 specificity across most samples of examinees for whom English is not the primary language, but well-below acceptable levels in individuals with dementia.Conclusions: The TOMM is highly specific when interpreted per traditional cutoffs. In individuals not suspected of significant impairment, findings indicate that a less conservative TOMM Trial 2 or Retention cutoff of <49 can be interpreted as invalid, especially in settings associated with higher base rates of invalidity and, thus, higher positive predictive power. A cutoff of <42 on Trial 1 can also be interpreted as invalid in most settings.