Verbal Episodic Memory Alterations and Hippocampal Atrophy in Acute Mild Traumatic Brain Injury

Impaired episodic verbal memory recall after 1 week and elevated forgetting in children after mild traumatic brain injury - results from a short-term longitudinal study

Objective

There is preliminary evidence that children after traumatic brain injury (TBI) have accelerated long-term forgetting (ALF), i.e., an adequate learning and memory performance in standardized memory tests, but an excessive rate of forgetting over delays of days or weeks. The main aim of this study was to investigate episodic memory performance, including delayed retrieval 1 week after learning, in children after mild TBI (mTBI).

Methods

This prospective study with two time-points (T1: 1 week after injury and T2: 3-6 months after injury), included data of 64 children after mTBI and 57 healthy control children aged between 8 and 16 years. We assessed episodic learning and memory using an auditory word learning test and compared executive functions (interference control, working memory, semantic fluency and flexibility) and divided attention between groups. We explored correlations between memory performance and executive functions. Furthermore, we examined predictive factors for delayed memory retrieval 1 week after learning as well as for forgetting over time.

Results

Compared to healthy controls, patients showed an impaired delayed recall and recognition performance 3-6 months after injury. Executive functions, but not divided attention, were reduced in children after mTBI. Furthermore, parents rated episodic memory as impaired 3-6 months after injury. Additionally, verbal learning and group, but not executive functions, were predictive for delayed recall performance at both time-points, whereas forgetting was predicted by group.

Discussion

Delayed recall and forgetting over time were significantly different between groups, both post-acutely and in the chronic phase after pediatric mTBI, even in a very mildly injured patient sample. Delayed memory performance should be included in clinical evaluations of episodic memory and further research is needed to understand the mechanisms of ALF.

The Effect of Traumatic Brain Injury on Memory

Having a good memory is essential for carrying out daily tasks. People cannot study, plan, remember or navigate life effectively if they are memoryless. People may be at risk when mistakes made in the past will be repeated and lessons regarding danger cannot be learned. In the community, traumatic brain injury (TBI) is common and individuals with TBI frequently have memory problems. It is crucial to study how TBI affects memory to better understand the underlying mechanism and to tailor rehabilitation for patients with a range of pathologies and severity levels. Thus, this paper aimed to review studies related to TBI's effect on memory. This review examined recent studies to learn more regarding and comprehend the connection between TBI and memory, including short-term memory (STM), working memory (WM) and long-term memory (LTM). This will undoubtedly have a big impact on how memory problems that may arise after TBI will be addressed. Virtual reality and other technological advancements have given the medical community a new way to investigate rehabilitative therapy.

The Neurobiological Links between Stress and Traumatic Brain Injury: A Review of Research to Date

Neurological dysfunctions commonly occur after mild or moderate traumatic brain injury (TBI). Although most TBI patients recover from such a dysfunction in a short period of time, some present with persistent neurological deficits. Stress is a potential factor that is involved in recovery from neurological dysfunction after TBI. However, there has been limited research on the effects and mechanisms of stress on neurological dysfunctions due to TBI. In this review, we first investigate the effects of TBI and stress on neurological dysfunctions and different brain regions, such as the prefrontal cortex, hippocampus, amygdala, and hypothalamus. We then explore the neurobiological links and mechanisms between stress and TBI. Finally, we summarize the findings related to stress biomarkers and probe the possible diagnostic and therapeutic significance of stress combined with mild or moderate TBI.

Olfactory perception in patients with a mild traumatic brain injury: a longitudinal study

OBJECTIVE

This longitudinal study aimed to evaluate olfactory perception in patients with first time mild traumatic brain injury (mTBI) 2-4 weeks (baseline) and 6 months (follow-up) following their trauma.

METHODS

At baseline, we enrolled 107 participants (54 healthy controls; 53 patients with mTBI). Thirty-nine healthy controls and 32 patients with mTBI returned for follow-up. We assessed odor detection (yes/no paradigm) and odor perception with a self-reported evaluation of intensity and pleasantness of four common odorants, by using an olfactometer, i.e., a computer controlled automated odor presentation device.

RESULTS

At baseline, patients with mTBI showed significantly more difficulty detecting odors; however, they perceived them as more intense and less pleasant. These effects vanished at follow-up.

CONCLUSION

These results suggest that patients with mTBI suffer from altered olfactory detection and perception in the first weeks following their trauma. This may have an impact on eating behavior and quality of life. Further, our data suggest recovery of olfactory function within the first six months following a head trauma.