Language impairments in traumatic brain injury: a window into complex cognitive performance

Multimodal Predictive Modeling: Scalable Imaging Informed Approaches to Predict Future Brain Health

Background

Predicting future brain health is a complex endeavor that often requires integrating diverse data sources. The neural patterns and interactions iden-tified through neuroimaging serve as the fundamental basis and early indica-tors that precede the manifestation of observable behaviors or psychological states.

New Method

In this work, we introduce a multimodal predictive modeling approach that leverages an imaging-informed methodology to gain insights into fu-ture behavioral outcomes. We employed three methodologies for evalua-tion: an assessment-only approach using support vector regression (SVR), a neuroimaging-only approach using random forest (RF), and an image-assisted method integrating the static functional network connectivity (sFNC) matrix from resting-state functional magnetic resonance imaging (rs-fMRI) alongside assessments. The image-assisted approach utilized a partially con-ditional variational autoencoder (PCVAE) to predict brain health constructs in future visits from the behavioral data alone.

Results

Our performance evaluation indicates that the image-assisted method ex-cels in handling conditional information to predict brain health constructs in subsequent visits and their longitudinal changes. These results suggest that during the training stage, the PCVAE model effectively captures relevant in-formation from neuroimaging data, thereby potentially improving accuracy in making future predictions using only assessment data.

Comparison with Existing Methods

The proposed image-assisted method outperforms traditional assessment-only and neuroimaging-only approaches by effectively integrating neuroimag-ing data with assessment factors.

Conclusion

This study underscores the potential of neuroimaging-informed predictive modeling to advance our comprehension of the complex relationships between cognitive performance and neural connectivity.

Highlights

Multifaceted perspective for studying longitudinal brain health changes.Showcases the versatility of methodologies through assessment-only, neuroimaging-only, and image-assisted predictive approaches.Provides predictive insights by revealing the neural patterns corresponding to alterations in behavior.

The Telephone Language Screener (TLS): standardization of a novel telephone-based screening test for language impairment

BACKGROUND

This study aimed at developing and standardizing the Telephone Language Screener (TLS), a novel, disease-nonspecific, telephone-based screening test for language disorders.

METHODS

The TLS was developed in strict pursuance to the current psycholinguistic standards. It comprises nine tasks assessing phonological, lexical-semantic and morpho-syntactic components, as well as an extra Backward Digit Span task. The TLS was administered to 480 healthy participants (HPs), along with the Telephone-based Semantic Verbal Fluency (t-SVF) test and a Telephone-based Composite Language Index (TBCLI), as well as to 37 cerebrovascular/neurodegenerative patients-who also underwent the language subscale of the Telephone Interview for Cognitive Status (TICS-L). An HP subsample was also administered an in-person language battery. Construct validity, factorial structure, internal consistency, test-retest and inter-rater reliability were tested. Norms were derived via Equivalent Scores. The capability of the TLS to discriminate patients from HPs and to identify, among the patient cohort, those with a defective TICS-L, was also examined.

RESULTS

The TLS was underpinned by a mono-component structure and converged with the t-SVF (p < .001), the TBCLI (p < .001) and the in-person language battery (p = .002). It was internally consistent (McDonald's ω = 0.67) and reliable between raters (ICC = 0.99) and at retest (ICC = 0.83). Age and education, but not sex, were predictors of TLS scores. The TLS optimally discriminated patients from HPs (AUC = 0.80) and successfully identified patients with an impaired TICS-L (AUC = 0.92). In patients, the TLS converged with TICS-L scores (p = 0.016).

DISCUSSION

The TLS is a valid, reliable, normed and clinically feasible telephone-based screener for language impairment.

Lateral fluid percussion injury: A rat model of experimental traumatic brain injury

Traumatic brain injury (TBI) represents one of the leading causes of disability and death worldwide. The annual economic impact of TBI-including direct and indirect costs-is high, particularly impacting low- and middle-income countries. Despite extensive research, a comprehensive understanding of the primary and secondary TBI pathophysiology, followed by the development of promising therapeutic approaches, remains limited. These fundamental caveats in knowledge have motivated the development of various experimental models to explore the molecular mechanisms underpinning the pathogenesis of TBI. In this context, the Lateral Fluid Percussion Injury (LFPI) model produces a brain injury that mimics most of the neurological and systemic aspects observed in human TBI. Moreover, its high reproducibility makes the LFPI model one of the most widely used rodent-based TBI models. In this chapter, we provide a detailed surgical protocol of the LFPI model used to induce TBI in adult Wistar rats. We further highlight the neuroscore test as a valuable tool for the evaluation of TBI-induced sensorimotor consequences and their severity in rats. Lastly, we briefly summarize the current knowledge on the pathological aspects and functional outcomes observed in the LFPI-induced TBI model in rodents.

Exploring how brain health strategy training informs the future of work

Introduction

The workplace typically affords one of the longest periods for continued brain health growth. Brain health is defined by the World Health Organization (WHO) as the promotion of optimal brain development, cognitive health, and well-being across the life course, which we expanded to also include connectedness to people and purpose. This work was motivated by prior work showing individuals, outside of an aggregate setting, benefitted from training as measured by significant performance gains on a holistic BrainHealth Index and its factors (i.e., clarity, connectedness, emotional balance). The current research was conducted during the changing remote work practices emerging post-pandemic to test whether a capacity-building training would be associated with significant gains on measures of brain health and components of burnout. The study also tested the influence of utilization of training modules and days in office for individuals to inform workplace practices.

Methods

We investigated whether 193 individuals across a firm's sites would improve on measures of brain health and burnout from micro-delivery of online tactical brain health strategies, combined with two individualized coaching sessions, and practical exercises related to work and personal life, over a six-month period. Brain health was measured using an evidenced-based measure (BrainHealth™ Index) with its components (clarity, connectedness, emotional balance) consistent with the WHO definition. Burnout was measured using the Maslach Burnout Inventory Human Services Survey. Days in office were determined by access to digital workplace applications from the firm's network. Regression analyses were used to assess relationships between change in BrainHealth factors and change in components of the Maslach Burnout Inventory.

Results

Results at posttest indicated that 75% of the individuals showed gains on a composite BrainHealth Index and across all three composite factors contributing to brain health. Benefits were directly tied to training utilization such that those who completed the core modules showed the greatest gains. The current results also found an association between gains on both the connectedness and emotional balance brain health factors and reduced on burnout components of occupational exhaustion and depersonalization towards one's workplace. We found that fewer days in the office were associated with greater gains in the clarity factor, but not for connectedness and emotional balance.

Discussion

These results support the value of a proactive, capacity-building training to benefit all employees to complement the more widespread limited offerings that address a smaller segment who need mental illness assistance programs. The future of work may be informed by corporate investment in focused efforts to boost collective brain capital through a human-centered, capacity-building approach. Efforts are underway to uncover the value of better brain health, i.e., Brainomics© - which includes economic, societal, and individual benefits.

Interaction of discourse processing impairments, communicative participation, and verbal executive functions in people with chronic traumatic brain injury

Introduction

Especially in the chronic phase, individuals with traumatic brain injury (TBI) (IwTBI) may still have impairments at the discourse level, even if these remain undetected by conventional aphasia tests. As a consequence, IwTBI may be impaired in conversational behavior and disadvantaged in their socio-communicative participation. Even though handling discourse is thought to be a basic requirement for participation and quality of life, only a handful of test procedures assessing discourse disorders have been developed so far. The MAKRO Screening is a recently developed screening tool designed to assess discourse impairments. The test construction is based on psycholinguistic frameworks and the concept of macro-rules, which refer to cognitive functions responsible for organizing and reducing complex information (e.g., propositional content) in discourse.

Aim

The aim of our study was to investigate discourse processing in IwTBI in different tasks and to assess problems in communicative participation in the post-acute and chronic phase. In this context, we also aimed to analyze the influence of the severity of the initial impairment and the verbal executive abilities on the discourse performance. Additionally, the impact of macrolinguistic discourse impairments and verbal fluency on perceived communicative participation was targeted in our analysis.

Methods

Data from 23 IwTBI (moderate to severe) and 23 healthy control subjects have been analyzed. They completed two subtests of the MAKRO screening: Text production and Inferences. Discourse performance was examined in relation to measures of semantic fluency and verbal task-switching. Socio-communicative problems were evaluated with the German version of the La Trobe Communication Questionnaire (LCQ).

Results

IwTBI showed lower test results than the control group in the two subtests of the MAKRO-Screening. Difficulties in picture-based narrative text production also indicated greater perceived difficulties in communicative participation (LCQ). We also found that the subject’s performance on the MAKRO-Screening subtests can partly be explained by underlying dysexecutive symptoms (in terms of verbal fluency and verbal task switching) and the severity of their injury. The preliminary results of our study show that cognitive-linguistic symptoms in IwTBI are also evident in the chronic phase. These can be detected with procedures referring to the discourse level, such as the MAKRO-Screening. The assessment of discourse performance should be an integral part in the rehabilitation of IwTBI in order to detect cognitive-linguistic communication disorders and to evaluate their impact on socio-communicative participation.

A Novel BrainHealth Index Prototype Improved by Telehealth-Delivered Training During COVID-19

Introduction: Brain health is neglected in public health, receiving attention after something goes wrong. Neuroplasticity research illustrates that preventive steps strengthen the brain's component systems; however, this information is not widely known. Actionable steps are needed to scale proven population-level interventions. Objectives: This pilot tested two main objectives: (1) the feasibility/ease of use of an online platform to measure brain health, deliver training, and offer virtual coaching to healthy adults and (2) to develop a data driven index of brain health. Methods: 180 participants, ages 18-87, enrolled in this 12-week pilot. Participants took a BrainHealth Index™ (BHI), a composite of assessments encompassing cognition, well-being, daily-life and social, pre-post training. Participants engaged in online training with three coaching sessions. We assessed changes in BHI, effects of training utilization and demographics, contributions of sub-domain measures to the BHI and development of a factor analytic structure of latent BrainHealth constructs. Results: The results indicated that 75% of participants showed at least a 5-point gain on their BHI which did not depend on age, education, or gender. The contribution to these gains were from all sub-domains, including stress, anxiety and resilience, even though training focused largely on cognition. Some individuals improved due to increased resilience and decreased anxiety, whereas others improved due to increased innovation and social engagement. Larger gains depended on module utilization, especially strategy training. An exploratory factor analytic solution to the correlation matrix of online assessments identified three latent constructs. Discussion/Conclusion: This pilot study demonstrated the efficacy of an online platform to assess changes on a composite BrainHealth Index and efficacy in delivering training modules and coaching. We found that adults, college age to late life, were motivated to learn about their brain and engage in virtual-training with coaching to improve their brain health. This effort intends to scale up to thousands, thus the pilot data, tested by an impending imaging pilot, will be utilized in ongoing machine learning (ML) algorithms to develop a precision brain health model. This pilot is a first step in scaling evidence-based brain health protocols to reach individuals and positively affect public health globally.

Cognitive Training and Transcranial Direct Current Stimulation in Mild Cognitive Impairment: A Randomized Pilot Trial

Background

Transcranial direct current stimulation (tDCS), a non-invasive stimulation, represents a potential intervention to enhance cognition across clinical populations including Alzheimer’s disease and mild cognitive impairment (MCI). This randomized clinical trial in MCI investigated the effects of anodal tDCS (a-tDCS) delivered to left inferior frontal gyrus (IFG) combined with gist-reasoning training (SMART) versus sham tDCS (s-tDCS) plus SMART on measures of cognitive and neural changes in resting cerebral blood flow (rCBF). We were also interested in SMART effects on cognitive performance regardless of the tDCS group.

Methods

Twenty-two MCI participants, who completed the baseline cognitive assessment (T1), were randomized into one of two groups: a-tDCS + SMART and s-tDCS + SMART. Of which, 20 participants completed resting pCASL MRI scan to measure rCBF. Eight SMART sessions were administered over 4 weeks with a-tDCS or s-tDCS stimulation for 20 min before each session. Participants were assessed immediately (T2) and 3-months after training (T3).

Results

Significant group × time interactions showed cognitive gains at T2 in executive function (EF) measure of inhibition [DKEFS- Color word (p = 0.047)], innovation [TOSL (p = 0.01)] and on episodic memory [TOSL (p = 0.048)] in s-tDCS + SMART but not in a-tDCS + SMART group. Nonetheless, the gains did not persist for 3 months (T3) after the training. A voxel-based analysis showed significant increase in regional rCBF in the right middle frontal cortex (MFC) (cluster-wise p = 0.05, k = 1,168 mm³) in a-tDCS + SMART compared to s-tDCS + SMART. No significant relationship was observed between the increased CBF with cognition. Irrespective of group, the combined MCI showed gains at T2 in EF of conceptual reasoning [DKEFS card sort (p = 0.033)] and category fluency [COWAT (p = 0.055)], along with gains at T3 in EF of verbal fluency [COWAT (p = 0.009)].

Conclusion

One intriguing finding is a-tDCS to left IFG plus SMART increased blood flow to right MFC, however, the stimulation seemingly blocked cognitive benefits of SMART on EF (inhibition and innovation) and episodic memory compared to s-tDCS + SMART group. Although the sample size is small, this paper contributes to growing evidence that cognitive training provides a way to significantly enhance cognitive performance in adults showing memory loss, where the role of a-tDCS in augmenting these effects need further study.

Association between uncooperativeness and the glucose metabolism of patients with chronic behavioral disorders after severe traumatic brain injury: a cross-sectional retrospective study

Bakground

Patients with behavioral disorders following severe traumatic brain injury (sTBI) often have disorders of consciousness that make expressing their emotional distress difficult. However, no standard method for assessing the unsettled and unforeseen responses that are associated with behavioral disorders has yet to be established. Because the thalamus is known to play a role in maintaining consciousness and cognition, we used 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) to examine the association between brain glucose metabolism in the thalamus and behavioral disorders.

Methods

We retrospectively analyzed 70 consecutive patients with sTBI who had been involved in motor vehicle accidents. To assess behavioral disorders, we evaluated 18 symptoms using the Brief Psychiatric Rating Scale (BPRS): Emotional Withdrawal, Conceptual Disorganization, Tension, Mannerisms and Posturing, Motor Retardation, Uncooperativeness, Blunted Affect, Excitement, Somatic Concern, Anxiety, Feeling of Guilt, Grandiosity, Depressive Mood, Hostility, Suspiciousness, Hallucinatory Behavior, Unusual Thought Content, and Disorientation. First, we identified clinical characteristics of sTBI patients with behavioral disorders. Next, we retrospectively analyzed 18F-FDG-PET/CT data to assess how thalamic activity was related with abnormal behaviors.

Results

Twenty-six patients possessed the minimum communicatory ability required for psychiatric interview. Among them, 15 patients (57.7%) were diagnosed with behavioral disorder, 14 of whom had reached a stable psychiatric state after about 426.6 days of treatment. Excitement (13 patients) and uncooperativeness (10 patients) were the most frequently observed symptoms. Available 18F-FDG-PET/CT data indicated that thalamic glucose metabolism was imbalanced and lateralized (p = 0.04) in 6 patients who exhibited uncooperativeness.

Conclusions

Behavioral symptoms of excitement and uncooperativeness were common in patients with sTBI, although most symptoms improved as the chronic stage continued. Our data support the idea that imbalanced laterality of glucose metabolism in the thalamus might be related to behavioral disorders characterized by uncooperativeness.

Trial registration

UMIN 000029531. Registered 27 March 2017, retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s13030-018-0125-0) contains supplementary material, which is available to authorized users.

Longitudinal changes in linguistic complexity among professional football players

Reductions in spoken language complexity have been associated with the onset of various neurological disorders. The objective of this study is to analyze whether similar trends are found in professional football players who are at risk for chronic traumatic encephalopathy. We compare changes in linguistic complexity (as indexed by the type-to-token ratio and lexical density) measured from the interview transcripts of players in the National Football League (NFL) to those measured from interview transcripts of coaches and/or front-office NFL executives who have never played professional football. A multilevel mixed model analysis reveals that exposure to the high-impact sport (vs no exposure) was associated with an overall decline in language complexity scores over time. This trend persists even after controlling for age as a potential confound. The results set the stage for a prospective study to test the hypothesis that language complexity decline is a harbinger of chronic traumatic encephalopathy.

Enhancing Executive Function and Neural Health in Bipolar Disorder through Reasoning Training

Cognitive deficits in executive function and memory among individuals with bipolar disorder (BD) are well-documented; however, only recently have efforts begun to address whether such cognitive deficits can be ameliorated through cognitive training. This pilot study examined the effects of a top-down, cognitive reasoning training program in adults with BD on both brain and cognitive measures. Twenty-seven participants (11 males, 16 females), aged 21-70 years old, completed the study. Participants completed neurocognitive testing and functional magnetic resonance imaging (fMRI) before and after training, consisting of 8 h (2 h/week) of training in small groups. The training delivered information processing strategies that were implemented and applicable to a variety of daily living contexts. Results indicated that participants showed significant gains in the primary outcome measure of complex abstraction, also referred to as gist reasoning, as well as in untrained domains of executive function and memory. We found a significant increase in resting cerebral blood flow (CBF) in left inferior frontal gyrus after cognitive training. We also found that resting CBF in the right frontal middle gyrus correlated positively with performance on the measure of complex abstraction. This feasibility study provides promising evidence that short-term reasoning training can enhance cognitive performance and brain health in adults with BD. These data motivate further efforts to explore adjuvant therapeutics to improve cognitive performance and underlying brain systems in bipolar, as well as other psychiatric disorders. Clinicaltrials.gov Identifier: NCT02843282, http://www.clinicaltrials.gov/ct2/show/NCT02843282.