Neurophysiological biomarkers of post-concussion syndrome: a scoping review

Background and objectives: Post-concussion syndrome (PCS) consists of neurologic and psy-chological complaints persisting after a mild traumatic brain injury (mTBI). It affects up to 50% of mTBI patients, causes long-term disability and reduces quality of life. The aim of this scoping review was to examine possible uses of different neuroimaging modalities in PCS. Methods: Articles from Pubmed database were screened to extract studies that investigated the relationship between any neuroimaging features and symptoms of PCS. Descriptive statistics were applied to report results. Results: 88 out of 939 papers were included in the final review. 12 examined conventional MRI (42% specificity), 27 diffusion weighted imaging (56% specificity), 25 functional MRI (84% specificity), 10 electro(magneto)encephalography (80% specificity), and 14 examined other tech-niques (71% specificity). Conclusion: MRI was the most widely used technique, while functional techniques seem to be the most sensitive tools to evaluate PCS. Common patterns associated with symptoms of PCS were a decreased anticorrelation between the default mode network and the task positive net-work and reduced brain activity in specific areas (most often prefrontal cortex). Significance: Our findings highlight the importance to use functional approaches which demonstrated a functional alternation in brain connectivity and activity in most studies assessing PCS.