Neuropsychology and clinical neuroscience of persistent post-concussive syndrome

Abstract

On the mild end of the acquired brain injury spectrum, the terms concussion and mild traumatic brain injury (mTBI) have been used interchangeably, where persistent post-concussive syndrome (PPCS) has been a label given when symptoms persist for more than three months post-concussion. Whereas a brief history of concussion research is overviewed, the focus of this review is on the current status of PPCS as a clinical entity from the perspective of recent advances in the biomechanical modeling of concussion in human and animal studies, particularly directed at a better understanding of the neuropathology associated with concussion. These studies implicate common regions of injury, including the upper brainstem, base of the frontal lobe, hypothalamic-pituitary axis, medial temporal lobe, fornix, and corpus callosum. Limitations of current neuropsychological techniques for the clinical assessment of memory and executive function are explored and recommendations for improved research designs offered, that may enhance the study of long-term neuropsychological sequelae of concussion. (JINS, 2008, 14, 1-22.)

Whiplash Injury and Mild Traumatic Brain Injury: Differential Effects on Cognitive Functioning?

“…Besides this, some patients showed also problems with the recognition of recently stored information from memory. Furthermore, mild deficits could also be seen on tests measuring executive functions whereas in most studies visuospatial functioning seemed to be preserved [1,[16][17][18]29,30]. The above described findings with regard to cognitive functioning after MTBI were also presented in a meta-analysis of Belanger et al [3] and Frencham et al [4].…”

“…), as a reaction to the injury and its consequences in the family, social and professional context, fatigue, a reduced health-related quality of life and the use of psycho-active drugs might also be the cause of reduced cognitive functioning [2,7,24,28,29]. Malingering is also thought to contribute to post-whiplash symptoms [30]. However, it must be said that patients with psychiatric morbidity, use of psychotropic medication or malingering are excluded in most studies investigating cognitive disturbances after WI.…”

“…According to some authors [22,[30][31][32], the majority of these lesions are mainly focal because they are localized in the white matter of the frontal and temporal (limbic) lobes.…”

Reduced brain connectivity and mental flexibility in mild traumatic brain injury

“…While the majority of individuals with an mTBI recover fully, it is well established that a significant proportion continue to suffer with physical, emotional, and cognitive symptoms. Of these symptom clusters, cognitive complaints can include, for example, difficulties with concentration, attention, memory confusion, and slowness in thinking 3, 4, 5, 6, 7. While these symptoms can be subtle, their persistent nature has garnered both clinical and research attention focused on elucidating the etiology, pathophysiology, and mechanism of these complaints.…”

Manifold learning and unwrapping using density ridges

“…Importantly, a significant percentage (10-15%) of individuals diagnosed with mild TBI experience persistent post-concussive symptoms (PPCS), which may lead to long-term disabilities [100]. Symptoms range from physical, such as headache; cognitive, such as difficulty concentrating; and emotional/behavioral, such as irritability and impulsivity.…”