Blood biomarkers for assessment of mild traumatic brain injury and chronic traumatic encephalopathy.

Mild traumatic brain injuries (mTBI) are prevalent and can result in significant debilitation. Current diagnostic methods have implicit limitations, with clinical assessment tools reliant on subjective self-reported symptoms or non-specific clinical observations, and commonly available imaging techniques lacking sufficient sensitivity to detect mTBI. A blood biomarker would provide a readily accessible detector of mTBI to meet the current measurement gap. Suitable options would provide objective and quantifiable information in diagnosing mTBI, in monitoring recovery, and in establishing a prognosis of resultant neurodegenerative disease, such as chronic traumatic encephalopathy (CTE). A biomarker would also assist in progressing research, providing suitable endpoints for testing therapeutic modalities and for further exploring mTBI pathophysiology. This review highlights the most promising blood-based protein candidates that are expressed in the central nervous system (CNS) and released into systemic circulation following mTBI. To date, neurofilament light (NF-L) may be the most suitable candidate for assessing neuronal damage, and glial fibrillary acidic protein (GFAP) for assessing astrocyte activation, although further work is required. Ultimately, the heterogeneity of cells in the brain and each marker's limitations may require a combination of biomarkers, and recent developments in microRNA (miRNA) markers of mTBI show promise and warrant further exploration.

A semi-quantitative sport-specific assessment of recurrent traumatic brain injury: the TraQ questionnaire and its application in American football.

Chronic traumatic encephalopathy (CTE) is very frequent and studied among contact sport players, above all American Football. Now, the defined diagnosis is only post-mortem and, consequently, more detailed diagnostic in-vivo instruments are needed to facilitate diagnosis and to allow a follow up. This clinical questionnaire (Trauma Questionnaire-TraQ) has been designed to investigate in parallel the traumatic load and clinical and cognitive subjective symptoms. It evaluates 4 anamnestic fields (specific sport activity, all previous pathological events, clinical manifestations compatible with TBI (traumatic brain injury) or CTE and subjective perception of personal memory efficacy with PRMQ questionnaire). The aim of TraQ questionnaire is to allow a standardized follow-up of active players and to identify subclinical disturbances that may become warnings. A pilot comparative study with TraQ on 105 subjects (75 AF players and 30 comparable people without a history of contact-sports activity) revealed that AF players have an increased amount of severe head trauma, an amplified level of subjective aggressiveness, more olfactory deficits but also more speech subjective problems, previously never related with CTE. In view of the obtained results, the TraQ seems to be useful (1) to obtain a better quantification of the traumatic load; (2) to differentiate the risk of long-term neurological consequences, allowing better management of different athletes right from the pre-symptomatic phases; (3) to manage prevention strategies if regularly applied to periodic visits to sports fitness; and (4) to identify the predisposing factors for the development of CTE and other neurological consequences of TBI with follow-up studies.

Post-traumatic amnesia and confusional state: hazards of retrospective assessment.

Retrospective assessment of post-traumatic amnesia (PTA) must take into account factors other than traumatic brain injury (TBI) which may impact on memory both at the time of injury and subsequent to the injury. These include analgesics, anaesthesia required for surgery, and the development of acute or post-traumatic stress disorder. This is relevant in clinical and medicolegal settings. Repeated assessments of the post-injury state, involving tests for continuing amnesia, risk promoting recall of events suggested by the examiner, or generating confabulations. The PTA syndrome affects the categorical autobiographical memory, and is accompanied by confusion as an essential component; this should be suspected from the initial or early Glasgow Coma Scale score (13-14/15) if not directly recorded by clinical staff. PTA by itself is only one of several indices of severity of TBI. The nature of the head injury, including observers' accounts, clinical and neuroimaging data, the possible role of other external injuries, blood loss, acute stress disorder and the potential for hypoxic brain injury, must be taken into account as well as concomitant alcohol or substance abuse, and systemic shock. A plausible mechanism for a TBI must be demonstrable, and other causes of amnesia excluded.