Network Analysis and Precision Rehabilitation for the Post-concussion Syndrome

Some people experience persistent symptoms following a mild traumatic brain injury (MTBI), and the etiology of those symptoms has been debated for generations. Post-concussion-like symptoms are caused by many factors both before and after MTBI, and this non-specificity is the bedrock of the conundrum regarding the existence of the post-concussion syndrome. A latent model or common cause theory for the syndrome is inconsistent with the prevailing biopsychosocial conceptualization. It is the thesis of this paper that adopting a network perspective for persistent symptoms following MTBI, including the post-concussion syndrome, could lead to new insights and targeted treatment and rehabilitation strategies. The network perspective posits that symptoms co-occur because they are strongly inter-related, activating, amplifying, and mutually reinforcing, not because they arise from a common latent disease entity. This approach requires a conceptual shift away from thinking that symptoms reflect an underlying disease or disorder toward viewing inter-related symptoms as constituting the syndrome or disorder. The symptoms do not arise from an underlying syndrome—the symptoms are the syndrome. A network analysis approach allows us to embrace heterogeneity and comorbidity, and it might lead to the identification of new approaches to sequenced care. The promise of precision rehabilitation requires us to better understand the interconnections among symptoms and problems so that we can produce more individualized and effective treatment and rehabilitation

Expert Panel Survey to Update the American Congress of Rehabilitation Medicine Definition of Mild Traumatic Brain Injury

Objective: As part of an initiative led by the Brain Injury Special Interest Group Mild Traumatic Brain Injury (TBI) Task Force of the American Congress of Rehabilitation Medicine (ACRM) to update the 1993 ACRM definition of mild TBI, the present study aimed to characterize current expert opinion on diagnostic considerations. Design: Cross-sectional web-based survey. Setting: Not applicable. Participants: An international, interdisciplinary group of clinician-scientists (N=31) with expertise in mild TBI completed the survey by invitation between May and July 2019 (100% completion rate). Interventions: Not applicable. Main Outcome Measures: Ratings of agreement with statements related to the diagnosis of mild TBI and ratings of the importance of various clinical signs, symptoms, test findings, and contextual factors for increasing the likelihood that the individual sustained a mild TBI, on a scale ranging from 1 (“not at all important”) to 10 (“extremely important”). Results: Men (n=25; 81%) and Americans (n=21; 68%) were over-represented in the sample. The survey revealed areas of expert agreement (eg, acute symptoms are diagnostically useful) and disagreement (eg, whether mild TBI with abnormal structural neuroimaging should be considered the same diagnostic entity as “concussion”). Observable signs were generally rated as more diagnostically important than subjective symptoms (Wilcoxon signed ranks test, Z=3.77; P&lt;.001; r=0.68). Diagnostic importance ratings for individual symptoms varied widely, with some common postconcussion symptoms (eg, fatigue) rated as unhelpful (&lt;75% of respondents indicated at least 5 out of 10 importance). Certain acute test findings (eg, cognitive and balance impairments) and contextual factors (eg, absence of confounds) were consistently rated as highly important for increasing the likelihood of a mild TBI diagnosis (≥75% of respondents indicated at least 7 out of 10). Conclusions: The expert survey findings identified several potential revisions to consider when updating the ACRM mild TBI definition, including preferentially weighing observable signs in a probabilistic framework, incorporating symptoms and test findings, and adding differential diagnosis considerations.</p

Association Between Concussions and Suicidality in High School Students in the United States

Importance: Prior research has shown a statistically significant association between sustaining a concussion and suicidality in adolescents, but this prior research controlled for relatively few variables predictive of suicidality. Objective: To examine whether sustaining a concussion remained a significant predictor of suicidality after controlling for relevant covariates (e.g., sexual abuse/assault, bullying, substance use, depression), hypothesizing that the relationship between concussion and suicidality would become non-significant after controlling for these variables. Design: This study involved secondary data analysis of the 2019 Youth Risk Behavior Surveillance (YRBS) System, a national cross-sectional study of adolescents. Analyses were stratified by gender. Setting: A national sampling of U.S. high school students. Participants: Eleven thousand two hundred sixty-two students in the YRBS database, including 5,483 boys and 5,779 girls. Exposure(s): Participants included in the analyses reported whether, in the last year, they experienced a concussion and/or suicidality. Main Outcomes and Measures: The main outcome was suicidality (i.e., ideation, planning, attempt), which was predicted by concussion in an unadjusted analysis and by concussion along with other risk factors in a multivariable analysis. Results: The final sample included 11,262 participants with available data on concussion and suicidality in the last year (14–18 years-old; 51.3% girls; 49.0% White). Per unadjusted odds ratios with 95% confidence intervals, there was a relationship between concussion and suicidal ideation [girls: OR = 1.46 (1.24, 1.73); boys: OR = 1.69 (1.41, 2.03)], planning (girls: OR = 1.39 [1.16, 1.66]; boys: OR = 1.76 [1.44, 2.14]), and attempt [girls: OR = 1.70 (1.32, 2.19); boys: OR = 3.13, (2.37, 4.15)]. These relationships became mostly non-significant after controlling for relevant risk factors for suicidality. The adjusted odds ratios showed no relationship between concussion and suicidal ideation [girls: OR = 1.11 (0.86, 1.44); boys: OR = 1.24 (0.92, 1.69)] or planning (girls: OR = 1.07 [0.82, 1.40]; boys: OR = 1.12 [0.82, 1.55]); but a significant relationship with suicide attempts in boys [OR = 1.98 (1.28, 3.04)], but not girls [OR = 1.05 (0.74, 1.49)]. Conclusions and Relevance: There was an association between concussion and suicidality in U.S. high school students; however, after controlling for other variables (e.g., depression, sexual abuse/assault, illicit drug use), there was no association between concussion and suicidality aside from a significant relationship between concussion and attempts in boys

Improving the Methodology for Identifying Mild Cognitive Impairment in Intellectually High-Functioning Adults Using the NIH Toolbox Cognition Battery

Objective: Low scores on neuropsychological tests are considered objective evidence of mild cognitive impairment. In clinical practice and research, it can be challenging to identify a cognitive deficit or mild cognitive impairment in high-functioning people because they are much less likely to obtain low test scores. This study was designed to improve the methodology for identifying mild cognitive impairment in adults who have above average or superior intellectual abilities. Method: Participants completed the National Institutes of Health Toolbox for the Assessment of Neurological and Behavioral Function Cognition Battery (NIHTB-CB). The sample included 384 adults between the ages of 20 and 85 who had completed either a 4-year college degree or who scored in the above average, superior, or very superior range on a measure of intellectual functioning, the Crystallized Composite score. Algorithms were developed, based on the absence of high scores and the presence of low scores, for identifying mild cognitive impairment. Results: Base rate tables for the presence of low scores and the absence of high scores are provided. The base rate for people with high average crystalized ability obtaining any one of the following, 5 scores \u3c 63rd percentile, or 4+ scores \u3c 50th percentile, or 3+ scores ≤ 25th percentile, or 2+ scores ≤ 16th percentile, is 15.5%. Conclusions: Algorithms were developed for identifying cognitive weakness or impairment in high-functioning people. Research is needed to test them in clinical groups, and to assess their association with clinical risk factors for cognitive decline and biomarkers of acquired neurological or neurodegenerative diseases

Norms matter: U.S. normative data under-estimate cognitive deficits in Norwegians with schizophrenia spectrum disorders

Objective: To illustrate and quantify how using different normative systems influences the accuracy of identifying cognitive impairment in people with schizophrenia spectrum disorders. Participants and methods: A convenience sample of 315 patients between 18 and 38 years of age referred for neuropsychological assessment at a psychiatric inpatient hospital in Bergen, Norway, was included. All completed the Norwegian version of the Repeatable Battery for the Assessment of Neuropsy-chological Status (RBANS). Results: There were statistically significant differences between the Immediate Memory, Visuospatial/Constructional, Language, Delayed Memory, and Total Scale Index scores when comparing the U.S. normative scores with the Scandinavian normative scores. The effect sizes were medium. The patient samples scored higher when using the U.S. normative data, suggesting less cognitive impairment. Conclusions: United States normative data yielded less impaired scores for Norwegians with schizophrenia spectrum disorders. The implications of using U.S. versus Scandinavian normative data are discussed.acceptedVersio

The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies.

Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved)

Changes in the distribution of nesting Arctic seaducks are not strongly related to variation in polar bear presence

Contemporary climate change is predicted to expose some species to altered predation regimes. Losses of Arctic sea ice are causing polar bears to increasingly forage on colonial seaduck eggs in lieu of ice-based hunting of marine mammals. Although polar bear predation of bird eggs has now been widely documented, it is unclear whether this change in predator behavior is having population-level consequences for Arctic breeding birds. In this study, we tested whether changes in the number of common eider nests on 76 islands in Hudson Strait, Canada, were related to variation in polar bear presence. We found that polar bear sign detected during eider breeding surveys was strongly correlated with spatial patterns of polar bears observed during aerial surveys. However, changes in eider nest count did not appear to be clearly related to polar bear sign at either the island scale or the island-cluster scale. This results of this study, therefore, suggest that the spatial overlap between eiders and polar bears varies across the landscape, but patterns of polar bear spatial variation do not seem to have driven large-scale redistribution of nesting common eiders

Preliminary Normative Study of ImPACT® in Finnish Professional Male Ice Hockey Players

Assessment of cognition is an important part of concussion management. The common paradigm of baseline and postinjury evaluations is recommended but due to the often lacking baseline data, reliable normative values are needed. The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®) battery is a widely used method of cognitive assessment offering several language options. There are few comparative studies between language groups on this test battery. ImPACT was administered at baseline to 184 Finnish male Professional Ice Hockey league players. The performance of the Finnish sample differed from previously published English and Czech language samples on the Visual Motor Speed and Reaction Time composites with medium effect-sizes (d = 0.38–0.52). Age, but not education or prior concussions, was associated with ImPACT performance. ImPACT performance is not uniform across language and culture groups and the findings highlight the need for language-specific norms. Finnish reference values for ImPACT for ages 26 are presented. A similar approach is encouraged for other languages.Peer reviewe

Multiple prior concussions are associated with symptoms in high school athletes

Objectives: The purpose of this study was to evaluate the association of prior concussion on baseline computerized neurocognitive testing in a large cohort of high school athletes. Methods: This is a retrospective cohort study of student athletes from 49 Maine High Schools in 2010 who underwent baseline computerized neurocognitive evaluation with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®). As part of the ImPACT®, subjects reported a prior history of concussion as well as demographic information and a symptom questionnaire. We used linear regression to evaluate the association of prior concussion with baseline: (1) ImPACT® composite scores; and (2) symptom scores. Results: Six thousand seventy-five subjects were included in the study, of whom 57% were boys. The majority of student athletes (85.3%) reported no prior history of concussion while 4.6% reported having sustained two or more prior concussions. On simple linear regression, increasing number of concussions was related to worse performance in verbal memory (P = 0.039) and greater symptoms scores (P < 0.001). On multivariate modeling, only the association with baseline symptoms remained (P < 0.001). Other factors associated with baseline symptom reporting in the multivariate model included mental health history, headache/migraine history, gender, developmental and/or learning problems, and number of prior concussions. Interpretation In this large-scale, retrospective survey study, history of multiple prior concussions was associated with higher symptom burden but not baseline computerized neurocognitive testing. The association between baseline symptom reporting and clinical and demographic factors was greater than the association with a history of multiple concussions

Possible Lingering Effects of Multiple Past Concussions

Background. The literature on lingering or “cumulative” effects of multiple concussions is mixed. The purpose of this study was to examine whether athletes with a history of three or more concussions perform more poorly on neuropsychological testing or report more subjective symptoms during a baseline, preseason evaluation. Hypothesis. Athletes reporting three or more past concussions would perform more poorly on preseason neurocognitive testing. Study Design. Case-control study. Methods. An archival database including 786 male athletes who underwent preseason testing with a computerized battery (ImPACT) was used to select the participants. Twenty-six athletes, between the ages of 17 and 22 with a history of three or more concussions, were identified. Athletes with no history of concussion were matched, in a case-control fashion, on age, education, self-reported ADHD, school, sport, and, when possible, playing position and self-reported academic problems. Results. The two groups were compared on the four neuropsychological composite scores from ImPACT using multivariate analysis of variance followed by univariate ANOVAs. MANOVA revealed no overall significant effect. Exploratory ANOVAs were conducted using Verbal Memory, Visual Memory, Reaction Time, Processing Speed, and Postconcussion Scale composite scores as dependent variables. There was a significant effect for only the Verbal Memory composite. Conclusions. Although inconclusive, the results suggest that some athletes with multiple concussions could have lingering memory deficits