Neurophysiological biomarkers of post-concussion syndrome: a scoping review

Background and objectivesPost-concussion syndrome (PCS) consists of neurologic and psychological 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. MethodsArticles 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. Results88 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 techniques (71% specificity). ConclusionMRI 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 network and reduced brain activity in specific areas (most often prefrontal cortex). SignificanceOur findings highlight the importance to use functional approaches which demonstrated a functional alternation in brain connectivity and activity in most studies assessing PCS. HighlightsO_LIpost-concussion syndrome causes long term problems for up to 50% of patients after concussion. C_LIO_LIAmong different neuroimaging techniques, fMRI and EEG show to be the most sensitive tools for PCS assessment. C_LIO_LIHeterogeneity of axonal injury, symptoms, and populations limits having a specific prognostic criteria for the PCS patients. C_LI