Repeated mild traumatic brain injuries impair visual discrimination learning in adolescent mice.

Cognitive deficits following a mild traumatic brain injury (mTBI) are common and are associated with learning deficits in school-age children. Some of these deficits include problems with long-term memory, working memory, processing speeds, attention, mental fatigue, and executive function. Processing speed deficits have been associated with alterations in white matter, but the underlying mechanisms of many of the other deficits are unclear. Without a clear understanding of the underlying mechanisms we cannot effectively treat these injuries. The goal of these studies is to validate a translatable touchscreen discrimination/reversal task to identify deficits in executive function following a single or repeated mTBIs. Using a mild closed skull injury model in adolescent mice we were able to identify clear deficits in discrimination learning following repeated injuries that were not present from a single mTBI. The repeated injuries were not associated with any deficits in motor-based behavior but did induce a robust increase in astrocyte activation. These studies provide an essential platform to interrogate the underlying neurological dysfunction associated with these injuries.

Spreading Depolarizations Occur in Mild Traumatic Brain Injuries and Are Associated with Postinjury Behavior.

Millions of people suffer mild traumatic brain injuries (mTBIs) every year, and there is growing evidence that repeated injuries can result in long-term pathology. The acute symptoms of these injuries may or may not include the loss of consciousness but do include disorientation, confusion, and/or the inability to concentrate. Most of these acute symptoms spontaneously resolve within a few hours or days. However, the underlying physiological and cellular mechanisms remain unclear. Spreading depolarizations (SDs) are known to occur in rodents and humans following moderate and severe TBIs, and SDs have long been hypothesized to occur in more mild injuries. Using a closed skull impact model, we investigated the presence of SDs immediately following a mTBI. Animals remained motionless for multiple minutes following an impact and once recovered had fewer episodes of movement. We recorded the defining electrophysiological properties of SDs, including the large extracellular field potential shifts and suppression of high-frequency cortical activity. Impact-induced SDs were also associated with a propagating wave of reduced cerebral blood flow (CBF). In the wake of the SD, there was a prolonged period of reduced CBF that recovered in approximately 90 min. Similar to SDs in more severe injuries, the impact-induced SDs could be blocked with ketamine. Interestingly, impacts at a slower velocity did not produce the prolonged immobility and did not initiate SDs. Our data suggest that SDs play a significant role in mTBIs and SDs may contribute to the acute symptoms of mTBIs.

Adapting an in-person patient-caregiver communication intervention to a tailored web-based format.

BACKGROUND: Interventions that target cancer patients and their caregivers have been shown to improve patient-caregiver communication, support, and emotional well-being. OBJECTIVE: To adapt an in-person communication intervention for cancer patients and caregivers to a web-based format, and to examine the usability and acceptability of the web-based program among representative users. METHODS: A tailored, interactive web-based communication program for cancer patients and their family caregivers was developed based on an existing in-person, nurse-delivered intervention. The development process involved: (1) building a multidisciplinary team of content and web design experts, (2) combining key components of the in-person intervention with the unique tailoring and interactive features of a web-based platform, and (3) conducting focus groups and usability testing to obtain feedback from representative program users at multiple time points. RESULTS: Four focus groups with 2-3 patient-caregiver pairs per group (n = 22 total participants) and two iterations of usability testing with four patient-caregiver pairs per session (n = 16 total participants) were conducted. Response to the program's structure, design, and content was favorable, even among users who were older or had limited computer and Internet experience. The program received high ratings for ease of use and overall usability (mean System Usability Score of 89.5 out of 100). CONCLUSIONS: Many elements of a nurse-delivered patient-caregiver intervention can be successfully adapted to a web-based format. A multidisciplinary design team and an iterative evaluation process with representative users were instrumental in the development of a usable and well-received web-based program.