A Multidimensional Approach to Post-concussion Symptoms in Mild Traumatic Brain Injury

Abstract

Mild traumatic brain injury (mTBI) presents a substantial burden to patients, families, and health care systems. Whereas, recovery can be expected in the majority of patients, a subset continues to report persisting somatic, cognitive, emotional, and/or behavioral problems, generally referred to as post-concussion syndrome (PCS). However, this term has been the subject of debate since the mechanisms underlying post-concussion symptoms and the role of pre- and post-injury-related factors are still poorly understood. We review current evidence and controversies concerning the use of the terms post-concussion symptoms vs. syndrome, its diagnosis, etiology, prevalence, assessment, and treatment in both adults and children. Prevalence rates of post-concussion symptoms vary between 11 and 82%, depending on diagnostic criteria, population and timing of assessment. Post-concussion symptoms are dependent on complex interactions between somatic, psychological, and social factors. Progress in understanding has been hampered by inconsistent classification and variable assessment procedures. There are substantial limitations in research to date, resulting in gaps in our understanding, leading to uncertainty regarding epidemiology, etiology, prognosis, and treatment. Future directions including the identification of potential mechanisms, new imaging techniques, comprehensive, multidisciplinary assessment and treatment options are discussed. Treatment of post-concussion symptoms is highly variable, and primarily directed at symptom relief, rather than at modifying the underlying pathology. Longitudinal studies applying standardized assessment strategies, diagnoses, and evidence-based interventions are required in adult and pediatric mTBI populations to optimize recovery and reduce the substantial socio-economic burden of post-concussion symptoms.

Keywords: diagnosis; etiology; mild traumatic brain injury; outcome; post-concussion symptoms; prevalence; treatment.

Figure 1

A model for the study of post-concussion symptoms after mTBI. Permission has been obtained to model our figure based on Yeates (13), © The International Neuropsychological Society 2010, published by Cambridge University Press.

Figure 2

The prevalence of post-concussion symptoms over time. Permission has been obtained to base our figure on data presented in Theadom (27).

Figure 3

Magnetic resonance images of patients with post-concussion symptoms. MRI findings in patients with mTBI, demonstrating multiple pathologies. In each case, cranial CT was normal. MRI was obtained within 48 h on injury. (A) Right frontal non-hemorrhagic contusion, noted on FLAIR image. (B) Linear microhemorrhages in left and right frontal lobes, noted on T2^* image. (C) Diffuse axonal injury lesion in splenium of corpus callosum, with restricted diffusion noted on DWI image. (D) Diffuse axonal injury, with multifocal lesions noted on diffusion tensor imaging (DTI). (E) Traumatic meningeal enhancement of subdural effusions, noted on post-gadolinium FLAIR image. (F) Traumatic microvascular injury.

1. - Top row represents a single healthy control. Bottom row represents a single TBI patient.

2. - Left column: Cerebral Blood Flow (CBF), assessed by arterial spin labeling.

3. - Right column: Cerebrovascular reactivity (CVR) assessed using BOLD response to hypercapnia.

Credit for figures: Figures A, B, C, E: Larry Latour, PhD, NINDS/NIH; D: Carlos Marquez de la Plata, PhD, University of Texas at Dallas; F: Franck Amyot, PhD, Uniformed Services University of the Health Sciences.