Traumatic brain injury, working memory-related neural processing, and alcohol experimentation behaviors in youth from the ABCD cohort

Adolescent traumatic brain injury (TBI) has long-term effects on brain functioning and behavior, impacting neural activity under cognitive load, especially in the reward network. Adolescent TBI is also linked to risk-taking behaviors including alcohol misuse. It remains unclear how TBI and neural functioning interact to predict alcohol experimentation during adolescence. Using Adolescent Brain Cognitive Development (ABCD) study data, this project examined if TBI at ages 9-10 predicts increased odds of alcohol sipping at ages 11-13 and if this association is moderated by neural activity during the Emotional EN-Back working memory task at ages 11-13. Logistic regression analyses showed that neural activity in regions of the fronto-basal ganglia network predicted increased odds of sipping alcohol by ages 11-13 (p < .05). TBI and left frontal pole activity interacted to predict alcohol sipping (OR = 0.507, 95% CI [0.303 - 0.846], p = .009) - increased activity predicted decreased odds of alcohol sipping for those with a TBI (OR = 0.516, 95% CI [0.314 - 0.850], p = .009), but not for those without (OR = 0.971, 95% CI [0.931 -1.012], p = .159). These findings suggest that for youth with a TBI, increased BOLD activity in the frontal pole, underlying working memory, may be uniquely protective against the early initiation of alcohol experimentation. Future work will examine TBI and alcohol misuse in the ABCD cohort across more time points and the impact of personality traits such as impulsivity on these associations.

Memory and Traumatic Brain Injury: Assessment and Management Practices of Speech-Language Pathologists

PURPOSE

Memory impairments are among the most commonly reported deficits and among the most frequent rehabilitation targets for individuals with traumatic brain injury (TBI). Memory and learning are also critical for rehabilitation success and broader long-term outcomes. Speech-language pathologists (SLPs) play a central role in memory management for individuals with TBI across the continuum of care. Yet, little is known about the current practice patterns of SLPs for post-TBI memory disorders. This study aims to examine the clinical management of memory disorders in adults with TBI by SLPs and identify opportunities to improve post-TBI memory outcomes.

METHOD

SLPs from across the continuum of care were recruited to complete an online survey. The survey assessed key practice areas specific to memory and memory disorders post-TBI, including education and training, knowledge and confidence, and assessment and treatment patterns.

RESULTS

Surveys from 155 SLPs were analyzed. Results revealed that TBI-specific training remains low in the field. Respondents varied in their practice patterns in assessing and treating memory disorders. Most SLPs do not appear to have access to appropriate standardized assessments to measure unique forms of memory. Respondents also reported a range of barriers and opportunities to advance memory outcomes following TBI and provided suggestions of areas in which they would like to see more basic and clinical research.

CONCLUSIONS

These findings establish a baseline of the current practices for clinical management of memory impairment in adults with TBI by SLPs. Improved opportunities for clinician training, the development of a single tool to assess multiple forms of memory, better access to existing memory assessments, and implementation of evidence-based interventions promise to lead to improved memory outcomes for individuals with TBI.

Response Inhibitory Control Varies with Different Sensory Modalities

Response inhibition plays an essential role in preventing anticipated and unpredictable events in our daily lives. It is divided into proactive inhibition, where subjects postpone responses to an upcoming signal, and reactive inhibition, where subjects stop an impending movement based on the presentation of a signal. Different types of sensory input are involved in both inhibitions; however, differences in proactive and reactive inhibition with differences in sensory modalities remain unclear. This study compared proactive and reactive inhibitions induced by visual, auditory, and somatosensory signals using the choice reaction task (CRT) and stop-signal task (SST). The experiments showed that proactive inhibitions were significantly higher in the auditory and somatosensory modalities than in the visual modality, whereas reactive inhibitions were not. Examining the proactive inhibition-associated neural processing, the auditory and somatosensory modalities showed significant decreases in P3 amplitudes in Go signal-locked event-related potentials (ERPs) in SST relative to those in CRT; this might reflect a decreasing attentional resource on response execution in SST in both modalities. In contrast, we did not find significant differences in the reactive inhibition-associated ERPs. These results suggest that proactive inhibition varies with different sensory modalities, whereas reactive inhibition does not.

Quantitative Mass Spectrometry Imaging of Metabolomes and Lipidomes for Tracking Changes and Therapeutic Response in Traumatic Brain Injury Surrounding Injured Area at Chronic Phase

Traumatic brain injury (TBI) is a complex disease process that may contribute to temporary or permanent disability. Tracking spatial changes of lipids and metabolites in the brain helps unveil the underlying mechanisms of the disease procession and therapeutic response. Here, the liquid microjunction surface sampling technique was used for mass spectrometry imaging of both lipids and metabolites in rat models of controlled cortical impact with and without XueFu ZhuYu decoction treatment, and the work was focused on the diffuse changes outside the injured area at chronic phase (14 days after injury). Quantitative information was provided for phosphotidylcholines and cerebrosides by adding internal standards in the sampling solvent. With principal component analysis for the imaging data, the midbrain was found to be the region with the largest diffuse changes following TBI outside the injured area. In detail, several phosphatidylcholines, phosphatidylethanolamines, phosphatidic acids, and diacylglycerols were found to be significantly up-regulated particularly in midbrain and thalamus after TBI and XFZY treatment. It is associated with the reported "self-repair" mechanisms at the chronic phase of TBI activated by neuroinflammation. Several glycosphingolipids were found to be increased in most of brain regions after TBI, which was inferred to be associated with neuroinflammation and oxidative stress triggered by TBI. Moreover, different classes of small matabolites were significantly changed after TBI, including fatty acids, amino acids, and purines. All these compounds were involved in 10 metabolic pathway networks, and 6 target proteins of XFZY were found related to the impacted pathways. These results shed light on the molecular mechanisms of TBI pathologic processes and therapeutic response.

Neural correlates and role of medication in reactive motor impulsivity in Tourette disorder

Abnormality of inhibitory control is considered to be a potential cognitive marker of tics in Tourette disorder (TD), attention deficit hyperactivity disorder (ADHD), and impulse control disorders. The results of the studies on inhibitory control in TD showed discrepant results. The aim of the present study was to assess reactive inhibitory control in adult TD patients with and without antipsychotic medication, and under emotional stimulation (visual images with positive, neutral and negative content). We assessed 31 unmedicated and 19 medicated TD patients and 26 matched healthy controls using the stop signal task as an index of reactive motor impulsivity and emotional stimulation with the aim to increase impulsivity. We performed a multimodal neuroimaging analysis using a regions of interest approach on grey matter signal, resting-state spontaneous brain activity and functional connectivity analyses. We found a higher reactive motor impulsivity in TD patients medicated with antipsychotics compared to unmedicated TD patients and controls. This propensity for reactive motor impulsivity in medicated TD patients was not influenced by ADHD or emotional stimulation. Neuroimaging results in medicated TD patients suggested that reactive motor impulsivity was underpinned by an increased grey matter signal from the right supplementary motor area and inferior frontal gyrus; decreased resting-state spontaneous activity of the left putamen; higher functional connectivity between the inferior frontal gyrus and the superior temporal gyri (bilaterally); lower functional connectivity between the cerebellum and the right subthalamic nucleus. Taken together, our data suggested (i) a deficit in reactive motor impulsivity in TD patients medicated with atypical antipsychotics that was unrelated to ADHD and (ii) that motor impulsivity was underpinned by structures and by functional connectivity of the fronto-temporo-basal ganglia-cerebellar pathway.

Evaluating Proactive Strategy in Patients With OCD During Stop Signal Task

OBJECTIVES

The aim of the present study was to investigate "Proactive-Adjustment hypothesis" (PA) during the Stop Signal Task (SST). The PA is implied in the highly inconsistent literature, and it deals with the role of response inhibition (RI) in obsessive-compulsive disorder (OCD). This hypothesis assumed that participants would balance stopping and going by adjusting the response threshold (RT) in the go task. We verified whether the PA strategy was also implemented in our clinical group.

METHODS

To reach this goal, we analyzed SST performances in a group of 36 patients with OCD and 36 healthy controls (HCs). To identify different participants' behaviors during the task, without preconceived notions regarding the diagnosis, we performed a cluster analysis. Furthermore, we analyzed the influence of drug therapy and we investigated whether the rule and reversal acquisition investigated with the Intra-Extra Dimensional Set Shift, differed in the two clusters.

RESULTS

We did not find any difference relative to the number of patients with OCD and HCs included in the two clusters. Furthermore, we found that only Not Proactive participants performed the task as fast as possible, while Proactive participants consistently slowed down their RTs and showed a lower number of Direction Errors, higher Stop Signal Delay, and worse cognitive flexibility.

CONCLUSIONS

Our results show that among patients with OCD the use of PA is changeable and does not differ from HCs. This finding supports the idea that the RI heterogeneity concerning patients with OCD could be related to PA. (JINS, 2018, 24, 703-714).

Lasting deficit in inhibitory control with mild traumatic brain injury

Being able to focus on a complex task and inhibit unwanted actions or interfering information (i.e., inhibitory control) are essential human cognitive abilities. However, it remains unknown the extent to which mild traumatic brain injury (mTBI) may impact these critical functions. In this study, seventeen patients and age-matched healthy controls (HC) performed a variant of the Stroop task and attention-demanding 4-choice response tasks (4CRT) with identical stimuli but two contexts: one required only routine responses and the other with occasional response conflicts. The results showed that mTBI patients performed equally well as the HC when the 4CRT required only routine responses. However, when the task conditions included occasional response conflicts, mTBI patients with even a single concussion showed a significant slow-down in all responses and higher error rates relative to the HC. Results from event-related functional magnetic resonance imaging (efMRI) revealed altered neural activity in the mTBI patients in the cerebellum-thalamo-cortical and the fronto-basal-ganglia networks regulating inhibitory control. These results suggest that even without apparent difficulties in performing complex attention-demanding but routine tasks, patients with mTBI may experience long-lasting deficits in regulating inhibitory control when situations call for rapid conflict resolutions.

Reliable estimation of inhibitory efficiency: to anticipate, choose or simply react?

Response inhibition is an important executive process studied by clinical and experimental psychologists, neurophysiologists and cognitive neuroscientists alike. Stop-signal paradigms are popular because they are grounded in a theory that provides methods to estimate the latency of an unobservable process: the stop-signal reaction time (SSRT). Critically, SSRT estimates can be biased by skew of the response time distribution and gradual slowing over the course of the experiment. Here, we present a series of experiments that directly compare three common stop-signal paradigms that differ in the distribution of response times. The results show that the widely used choice response (CR) and simple response (SR) time versions of the stop-signal paradigm are particularly susceptible to skew of the response time distribution and response slowing, and that using the anticipated response (AR) paradigm based on the Slater-Hammel task offers a viable alternative to obtain more reliable SSRT estimates.

Mild cognitive impairment and structural brain abnormalities in a sexagenarian with a history of childhood traumatic brain injury

In this report, we present a case study involving an older, female patient with a history of pediatric traumatic brain injury (TBI). Magnetic resonance imaging and diffusion tensor imaging volumes were acquired from the volunteer in question, her brain volumetrics and morphometrics were extracted, and these were then systematically compared against corresponding metrics obtained from a large sample of older healthy control (HC) subjects as well as from subjects in various stages of mild cognitive impairment (MCI) and Alzheimer disease (AD). Our analyses find the patient's brain morphometry and connectivity most similar to those of patients classified as having early-onset MCI, in contrast to HC, late MCI, and AD samples. Our examination will be of particular interest to those interested in assessing the clinical course in older patients having suffered TBI earlier in life, in contradistinction to those who experience incidents of head injury during aging.