Chasing Biomarkers in Post-concussion Syndrome

Neurofilament Light Chain, Inflammatory Markers, Calcitonin Gene-related Peptide, and Kynurenine Metabolites in Patients With Severe Post-concussive Symptoms

The goal of this study was to investigate the biomarkers, neurofilament light chain, inflammatory markers, calcitonin-gene-related peptide, and metabolites from the kynurenine pathway in patients with severe post-concussive symptoms. The main question it aimed to answer was:

• Are the biomarker concentrations significantly changed in patients with severe post-concussive symptoms compared to healthy individuals?
• Do the biomarker concentrations change at follow-up?

Participants were recruited from a recently published randomized controlled trial (Clinicaltrials.gov no. NCT02337101 / PMID: 31891145 ). The biomarker concentrations were compared to a healthy control group recruited from the Blood Bank at Aarhus University Hospital in 2022.

In the previously published RCT-study (PMID: 31891145), 86 participants with severe post-concussive symptoms provided blood samples at baseline (4 months after the concussion). Severe post-concussive symptoms were defined as having a Rivermead Post Concussion Questionnaire >20.

Around 7 months later, a follow-up blood sample was obtained from 54 participants.

These blood samples were used to investigate blood biomarkers for the condition.

Patients with severe post-concussive symptoms:

Inclusion Criteria:

1. Concussion caused by a head trauma based on the diagnostic criteria recommended by the World Health Organization (WHO) Task Force
2. Age between 18 and 30 years
3. Able to understand, speak and read Danish.
4. A score of 20 or more on the Rivermead Post Concussion Symptoms Questionnaire (RPQ).

Exclusion Criteria:

1. Objective neurological findings indicating neurological disease or brain damage.
2. Previous concussion leading to persistent post-concussional symptoms within the last two years.
3. Severe misuse of alcohol, prescription drugs and / or illegal drugs.
4. Severe psychiatric, neurological,or other medical disease that would impede participation in the intervention
5. Inability to speak and read Danish

Healthy control group (recruited from December 2021 - March 2022):

- Individuals from the Blood Bank at Aarhus University Hospital in Denmark.

Inclusion criteria were:

1. Age between 18-30 years
2. Equal distribution between the genders (60 men and 60 women). This number was based on a power analysis using published data from neurofilament light chain.