Mild Traumatic Brain Injury From Repeated Low-Level Blast Exposures

2015 ◽  
Author(s):  
Jessica M. Wong ◽  
Adam L. Halberstadt ◽  
Humberto A. Sainz ◽  
Kiran S. Mathews ◽  
Brian W. Chu ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Shock Tube ◽  
Mild Traumatic Brain Injury ◽  
Fear Learning ◽  
Contextual Fear ◽  
Low Level ◽  
Dose Accumulation ◽  
Blast Effects ◽  
Four Levels

Recent studies on military breachers in training environments suggest that there are neurocognitive risks from exposure to repeated low-level blasts. However, the dose accumulation effects from multiple low-level blast exposures and their relation to mild traumatic brain injury (mTBI) are not well understood. This paper presents a controlled neurobehavioral study of behavioral effects from repeated low-level blasts delivered at ten second intervals using a rat model. A custom designed shock tube was developed to deliver repeated low-level blasts to rats at short intervals on the order of seconds. A total of 192 rats were divided into three cohorts of 64 for testing. Each cohort was exposed to a different blast intensity (7.5, 15, or 25 psi reflective pressure with durations <0.25 ms), and each cohort was further divided into four levels of blast repetition (0, 5, 10, or 15 repeats). Shock tube blasts were directed at the rat’s head, and startle with prepulse inhibition (PPI) and fear learning and extinction behavioral tests were performed to evaluate the blast effects. Behavioral testing results showed that repeated low-level blasts can affect PPI and contextual fear recall. PPI was not affected by repeated exposures to 7.5 psi blasts, but repeated 15 and 25 psi blasts disrupted PPI. All cohorts showed significant fear learning, but the highest blast group (25 psi, 15 repeats) had disruptions in spatial memory recall. None of the cohorts showed effects on cued fear recall or fear extinction and retention. The data collected are being used in continuous research to understand how the behavioral changes relate to mTBI, and how these animal tests can be scaled and modeled to interpret possible outcomes for humans.

scholarly journals Sex Differences in Behavioral Sensitivities After Traumatic Brain Injury

2020 ◽  
Vol 11 ◽  
Author(s):  
Ann N. Hoffman ◽  
Sonya L. Watson ◽  
Anna S. Makridis ◽  
Anisha Y. Patel ◽  
Sarah T. Gonzalez ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Sex Differences ◽  
Brain Injury ◽  
White Noise ◽  
Fear Conditioning ◽  
Fear Learning ◽  
Male Rats ◽  
Sensory Stimuli ◽  
Contextual Fear ◽  
The Impact

Traumatic brain injury (TBI) is associated with high rates of post-injury psychiatric and neurological comorbidities. TBI is more common in males than females despite females reporting more symptoms and longer recovery following TBI and concussion. Both pain and mental health conditions like anxiety and post-traumatic stress disorder (PTSD) are more common in women in the general population, however the dimorphic comorbidity in the TBI population is not well-understood. TBI may predispose the development of maladaptive anxiety or PTSD following a traumatic stressor, and the impact of sex on this interaction has not been investigated. We have shown that white noise is noxious to male rats following fluid percussion injury (FPI) and increases fear learning when used in auditory fear conditioning, but it is unclear whether females exhibit a similar phenotype. Adult female and male rats received either lateral FPI or sham surgery and 48 h later received behavioral training. We first investigated sex differences in response to 75 dB white noise followed by white noise-signaled fear conditioning. FPI groups exhibited defensive behavior to the white noise, which was significantly more robust in females, suggesting FPI increased auditory sensitivity. In another experiment, we asked how FPI affects contextual fear learning in females and males following unsignaled footshocks of either strong (0.9 mA) or weaker (0.5 mA) intensity. We saw that FPI led to rapid acquisition of contextual fear compared to sham. A consistent pattern of increased contextual fear after TBI was apparent in both sexes across experiments under differing conditioning protocols. Using a light gradient open field task we found that FPI females showed a defensive photophobia response to light, a novel finding supporting TBI enhanced sensory sensitivity across modalities in females. General behavioral differences among our measures were observed between sexes and discussed with respect to interpretations of TBI effects for each sex. Together our data support enhanced fear following a traumatic stressor after TBI in both sexes, where females show greater sensitivity to sensory stimuli across multiple modalities. These data demonstrate sex differences in emergent defensive phenotypes following TBI that may contribute to comorbid PTSD, anxiety, and other neurological comorbidities.

The Speech-Language Pathologists' Role in Mild Traumatic Brain Injury for Middle and High School–Age Children: Viewpoints on Guidelines From the Centers for Disease Control and Prevention

2019 ◽  
Vol 28 (3) ◽  
pp. 1363-1370 ◽  
Author(s):  
Jessica Brown ◽  
Katy O'Brien ◽  
Kelly Knollman-Porter ◽  
Tracey Wallace
Keyword(s):  
High School ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Disease Control ◽  
Mild Traumatic Brain Injury ◽  
School Age Children ◽  
School Age ◽  
Speech Language Pathologists ◽  
Control And Prevention ◽  
Centers For Disease Control

Purpose The Centers for Disease Control and Prevention (CDC) recently released guidelines for rehabilitation professionals regarding the care of children with mild traumatic brain injury (mTBI). Given that mTBI impacts millions of children each year and can be particularly detrimental to children in middle and high school age groups, access to universal recommendations for management of postinjury symptoms is ideal. Method This viewpoint article examines the CDC guidelines and applies these recommendations directly to speech-language pathology practices. In particular, education, assessment, treatment, team management, and ongoing monitoring are discussed. In addition, suggested timelines regarding implementation of services by speech-language pathologists (SLPs) are provided. Specific focus is placed on adolescents (i.e., middle and high school–age children). Results SLPs are critical members of the rehabilitation team working with children with mTBI and should be involved in education, symptom monitoring, and assessment early in the recovery process. SLPs can also provide unique insight into the cognitive and linguistic challenges of these students and can serve to bridge the gap among rehabilitation and school-based professionals, the adolescent with brain injury, and their parents. Conclusion The guidelines provided by the CDC, along with evidence from the field of speech pathology, can guide SLPs to advocate for involvement in the care of adolescents with mTBI. More research is needed to enhance the evidence base for direct assessment and treatment with this population; however, SLPs can use their extensive knowledge and experience working with individuals with traumatic brain injury as a starting point for post-mTBI care.

Assessment of Cognitive-Communicative Disorders of Mild Traumatic Brain Injury Sustained in Combat

2009 ◽  
Vol 19 (2) ◽  
pp. 47-57 ◽  
Author(s):  
Christine Parrish ◽  
Carole Roth ◽  
Brooke Roberts ◽  
Gail Davie
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Mild Traumatic Brain Injury ◽  
Psychological Health ◽  
Communication Disorders ◽  
Service Members ◽  
Patient Questionnaire ◽  
Speech Language Pathologists ◽  
Test Protocol ◽  
Communication Deficits

Abstract Background: Mild traumatic brain injury (mTBI) is recognized as the signature injury of the current conflicts in Iraq and Afghanistan, yet there remains limited understanding of the persisting cognitive deficits of mTBI sustained in combat. Speech-language pathologists (SLPs) have traditionally been responsible for evaluating and treating the cognitive-communication disorders following severe brain injuries. The evaluation instruments historically used are insensitive to the subtle deficits found in individuals with mTBI. Objectives: Based on the limited literature and clinical evidence describing traditional and current tests for measuring cognitive-communication deficits (CCD) of TBI, the strengths and weaknesses of the instruments are discussed relative to their use with mTBI. It is necessary to understand the nature and severity of CCD associated with mTBI for treatment planning and goal setting. Yet, the complexity of mTBI sustained in combat, which often co-occurs with PTSD and other psychological health and physiological issues, creates a clinical challenge for speech-language pathologists worldwide. The purpose of the paper is to explore methods for substantiating the nature and severity of CCD described by service members returning from combat. Methods: To better understand the nature of the functional cognitive-communication deficits described by service members returning from combat, a patient questionnaire and a test protocol were designed and administered to over 200 patients. Preliminary impressions are described addressing the nature of the deficits and the challenges faced in differentiating the etiologies of the CCD. Conclusions: Speech-language pathologists are challenged with evaluating, diagnosing, and treating the cognitive-communication deficits of mTBI resulting from combat-related injuries. Assessments that are sensitive to the functional deficits of mTBI are recommended. An interdisciplinary rehabilitation model is essential for differentially diagnosing the consequences of mTBI, PTSD, and other psychological and physical health concerns.

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