Cohort Differences in Neurobehavioral Symptoms in Chronic Mild to Severe Traumatic Brain Injury

Neurobehavioral Symptom Profiles for the Behavioral Assessment Screening Tool in Chronic Traumatic Brain Injury

OBJECTIVE

To identify neurobehavioral symptom profiles among persons with chronic traumatic brain injury (TBI) using the Behavioral Assessment Screening Tool (BAST) and to consider participant characteristics that differ between profile groups.

SETTING

Community.

PARTICIPANTS

Participants (n = 615) were English-speaking adults (≥18) and had a self-reported history of at least one TBI of any severity.

DESIGN

Secondary analysis of cross-sectional data.

MAIN MEASURES

The BAST measures neurobehavioral symptoms in the domains of Negative Affect, Fatigue, Executive Dysfunction, Impulsivity, and Substance Misuse.

RESULTS

Using latent profile analysis (LPA), we identified 3 different neurobehavioral profiles. Overall symptom frequency and differences in the pattern of symptom frequency across domains differentiated the profile groups. Average domain scores differed significantly across the profiles ( P < .001) for all domains except Fatigue ( P = .076). Those in profile 3 (High-Risk group) reported the most frequent symptoms across all domains (similar Negative Affect frequency as profile 1). Substance Misuse was especially high in this group. Compared to profile 2 (High Negative Affect group), participants in profile 1 (Moderate-Risk group) endorsed significantly more frequent (and more variable) symptoms across all BAST domains, particularly Impulsivity and Substance Misuse. Participants in profile 2 endorsed the least frequent symptoms across all domains. Demographic comparison showed that groups differed based on gender, age, and injury severity (mild vs moderate-severe), with profile 3 composed of the most men and the most persons in early adulthood, and profile 2 composed of the most women and those with mild TBI.

CONCLUSIONS

We differentiated 3 neurobehavioral symptom profiles among persons with chronic TBI and determined differences in sociodemographic factors between the groups. Future research should focus on validating these profiles in another sample of individuals with chronic TBI. Characterizing persons according to multidimensional symptom profiles could allow for more tailored approaches to predict and prevent long-term negative outcomes.

Convergent, discriminant, and known groups validity of the Behavioral Assessment Screening Tool (BAST) in chronic traumatic brain injury

The Behavioral Assessment Screening Tool (BAST) measures self-reported neurobehavioral symptoms commonly experienced by adults with traumatic brain injury (TBI). To assess the convergent, discriminant, and known-groups validity of the BAST among community-dwelling adults with chronic traumatic brain injury (TBI), we conducted correlation analyses and tests of group differences with previously validated symptom measures in two samples (n = 111, n = 134). Measures used for comparison were: Patient Health Questionnaire (depression), Generalized Anxiety Disorder-7 (anxiety), Positive and Negative Affect Schedule, Frontal Systems Behavior Scale (Executive Dysfunction, Apathy, Disinhibition), Modified Fatigue Impact Scale, PROMIS Fatigue, Aggression Questionnaire (anger, hostility, physical and verbal aggression), and Alcohol Use Disorders Test (alcohol misuse). BAST subscales had stronger correlations with measures of similar (|r|=.602-.828, p < .001) and related (|r|>.30, p < .001) constructs and weaker correlations (|r|<.300) with measures of dissimilar/unrelated constructs, supporting hypotheses of convergent and discriminant validity, respectively. Statistically significant group differences (p's < .001) in BAST subscales were found, with large effect sizes (Cohen's d = 1.2-1.9), for known-groups with moderate-severe depression, moderate-severe anxiety, clinically significant fatigue, problematic disinhibited and frontal-executive behaviors, and alcohol use.

Conclusions

Results support the convergent and discriminant validity of the BAST subscales. The BAST was specifically developed as a self-reported measure for remote symptom reporting, supporting its incorporation into mobile health platforms to improve chronic symptom monitoring in community-dwelling adults with TBI. With further validation research, the BAST could be used for early identification of persons with TBI who could benefit from intervention.

Acute axon damage and demyelination are mitigated by 4-aminopyridine (4-AP) therapy after experimental traumatic brain injury

Damage to long axons in white matter tracts is a major pathology in closed head traumatic brain injury (TBI). Acute TBI treatments are needed that protect against axon damage and promote recovery of axon function to prevent long term symptoms and neurodegeneration. Our prior characterization of axon damage and demyelination after TBI led us to examine repurposing of 4-aminopyridine (4-AP), an FDA-approved inhibitor of voltage-gated potassium (Kv) channels. 4-AP is currently indicated to provide symptomatic relief for patients with chronic stage multiple sclerosis, which involves axon damage and demyelination. We tested clinically relevant dosage of 4-AP as an acute treatment for experimental TBI and found multiple benefits in corpus callosum axons. This randomized, controlled pre-clinical study focused on the first week after TBI, when axons are particularly vulnerable. 4-AP treatment initiated one day post-injury dramatically reduced axon damage detected by intra-axonal fluorescence accumulations in Thy1-YFP mice of both sexes. Detailed electron microscopy in C57BL/6 mice showed that 4-AP reduced pathological features of mitochondrial swelling, cytoskeletal disruption, and demyelination at 7 days post-injury. Furthermore, 4-AP improved the molecular organization of axon nodal regions by restoring disrupted paranode domains and reducing Kv1.2 channel dispersion. 4-AP treatment did not resolve deficits in action potential conduction across the corpus callosum, based on ex vivo electrophysiological recordings at 7 days post-TBI. Thus, this first study of 4-AP effects on axon damage in the acute period demonstrates a significant decrease in multiple pathological hallmarks of axon damage after experimental TBI.

Rasch analysis of the Behavioral Assessment Screening Tool (BAST) in chronic traumatic brain injury

The Behavioral Assessment Screening Tool (BAST) measures neurobehavioral symptoms in adults with traumatic brain injury (TBI). Exploratory Factor Analyses established five subscales: Negative Affect, Fatigue, Executive Function, Impulsivity, and Substance Abuse. In the current study, we assessed all the subscales except Substance Abuse using Rasch analysis following the Rasch Reporting Guidelines in Rehabilitation Research (RULER) framework. RULER identifies unidimensionality and fit statistics, item hierarchies, targeting, and symptom severity strata as areas of interest for Rasch analysis. The BAST displayed good unidimensionality with only one item from the Impulsivity scale exhibiting potential item misfit (MnSQ 1.40). However, removing this item resulted in a lower average domain measure (1.42 to -1.49) and higher standard error (0.34 to 0.43) so the item was retained. Items for each of the four subscales also ranged in difficulty (i.e. endorsement of symptom frequency) with more severe symptoms being endorsed in the Fatigue subscale and more mild symptoms being endorsed in the Impulsivity subscale. Though Negative Affect and Executive Function displayed appropriate targeting, the Fatigue and Impulsivity Subscales had larger average domain values (1.35 and -1.42) meaning that more items may need to be added to these subscales to capture differences across a wider range of symptom severity. The BAST displayed excellent reliability via item and person separation indices and distinct strata for each of the four subscales. Future work should use Rasch analysis in a larger, more representative sample, include more items for the Fatigue and Impulsivity subscale, and include the Substance Abuse subscale.

Epidemiology of Chronic Effects of Traumatic Brain Injury

Although many patients diagnosed with traumatic brain injury (TBI), particularly mild TBI, recover from their symptoms within a few weeks, a small but meaningful subset experience symptoms that persist for months or years after injury and significantly impact quality of life for the person and their family. Factors associated with an increased likelihood of negative TBI outcomes include not only characteristics of the injury and injury mechanism, but also the person’s age, pre-injury status, comorbid conditions, environment, and propensity for resilience. In this article, as part of the Brain Trauma Blueprint: TBI State of the Science framework, we examine the epidemiology of long-term outcomes of TBI, including incidence, prevalence, and risk factors. We identify the need for increased longitudinal, global, standardized, and validated assessments on incidence, recovery, and treatments, as well as standardized assessments of the influence of genetics, race, ethnicity, sex, and environment on TBI outcomes. By identifying how epidemiological factors contribute to TBI outcomes in different groups of persons and potentially impact differential disease progression, we can guide investigators and clinicians toward more-precise patient diagnosis, along with tailored management, and improve clinical trial designs, data evaluation, and patient selection criteria.

Psychometric analysis of the behavioral assessment screening tool (BAST) in adults with stroke

PURPOSE

The purpose of this study was to examine the initial psychometric properties of the Behavioral Assessment Screening Tool (BAST), a self-reported measure of neurobehavioral symptoms, in adults with stroke.

METHODS

We assessed subscale and item-level reliabilities of the five BAST subscales in 75 community-dwelling adults with stroke. We further assessed the known-groups validity of the BAST to differentiate individuals with and without self-reported lifetime stroke history (n = 47 with stroke and n = 1843 neurologically healthy controls).

RESULTS

Cronbach's alpha coefficients of all subscales were >0.7, demonstrating acceptable to good internal consistency reliabilities, and corrected item-total correlations were all >.30 demonstrating good item-level reliabilities. ROC curves demonstrated strong known-groups validity of the negative affect, executive function, and fatigue subscales for classifying stroke versus healthy controls (AUC = .669-.758, p < .001).

CONCLUSION

The BAST demonstrates good initial psychometric properties as a screening tool to identify neurobehavioral symptoms in community-dwelling adults with stroke. Future work will add stroke-specific items, further assess the validity of the BAST, and employ item response theory or Rasch analyses to identify highly discriminative items for potential smart device-based ecological momentary assessments.