Summary: A new study suggests that measuring neurofilament light chain (NfL) levels 48 hours after a cardiac arrest can accurately predict a survivor’s long-term cognitive health. Researchers compared NfL to the currently used biomarker, neuron-specific enolase (NSE), and found that NfL had significantly higher diagnostic performance.
While high NfL levels were directly linked to lower scores on the Montreal Cognitive Assessment (MoCA) months later, NSE showed no such association. This discovery could allow clinicians to identify high-risk patients early, helping to tailor rehabilitation and manage family expectations.
Key Facts
- The NfL Advantage: Neurofilament light chain levels measured early after hospital admission were inversely correlated with long-term memory and thinking scores.
- NSE Reliability Issues: The standard biomarker, neuron-specific enolase, failed to show any significant association with future cognitive outcomes in this study.
- The 48-Hour Window: Testing blood just two days after resuscitation provides a critical “early warning” of potential brain injury while the patient is still comatose.
- Clinical Optimization: Routine NfL testing could help doctors prioritize expensive scans and specialized rehabilitation for the patients who need it most.
Source: European Society of Cardiology
Routine early measurement of neurofilament light chain could help improve prediction of cognitive impairment after out-of-hospital cardiac arrest, according to a study presented today at ESC Acute CardioVascular Care 2026, the annual congress of the Association for Acute CardioVascular Care (ACVC), a branch of the European Society of Cardiology (ESC).
After an out-of-hospital cardiac arrest, the brain is highly susceptible to injury and a range of tests are used by clinicians to predict if survivors have brain damage. “Currently, we measure neuron-specific enolase in the blood as a marker of brain injury but there are concerns about its reliability as factors other than brain damage can lead to high levels,” explained study presenter, Doctor Martin Meyer from Rigshospitalet – Copenhagen University, Denmark.
He continued: “Another blood biomarker, neurofilament light chain, has potentially better diagnostic performance than neuron-specific enolase. We compared neurofilament light chain and neuron-specific enolase for the prediction of long-term cognitive function in survivors of out-of-hospital cardiac arrest.”
The study analysed blood samples from participants in the Blood Pressure and Oxygenation Targets after Cardiac Arrest (BOX) trial who had been resuscitated from out-of-hospital cardiac arrest and were comatose on hospital admission. Levels of neurofilament light chain and levels of neuron-specific enolase were measured in samples taken 48 hours after cardiac arrest.
Data on cognitive function, assessed by the Montreal Cognitive Assessment (MoCA) score months after the cardiac arrest, were available for a subset of survivors who had both neurofilament light chain and neuron-specific enolase measurements.
The key finding of the investigation is that neurofilament light chain levels at 48 hours were inversely correlated with MoCA score, i.e. higher blood levels of neurofilament light chain were indicative of worse long-term cognitive function.
In contrast, no association was observed for neuron-specific enolase levels at 48 hours and cognitive function at follow-up.
Summing up the findings, Doctor Meyer concluded: “Neurofilament light chain levels measured early after cardiac arrest, while patients were still admitted to hospital, were related to long-term cognitive function. This association with cognitive function was not observed with neuron-specific enolase testing.
“The introduction of routine early neurofilament light chain measurement could potentially assist in the identification of patients at high risk, helping to optimise decision-making about other tests and scans, improve the targeting of rehabilitation and enable clinicians to better inform patients and their families about expectations for the future.”
Further validation and standardisation of neurofilament light chain assays are now needed.
Key Questions Answered:
A: In the context of cardiac arrest, yes. This study shows that when brain cells are damaged, they “leak” neurofilament light chain into the blood. Measuring that leak 48 hours after the event acts as a powerful predictor of future cognitive struggles.
A: The current test (NSE) can be “fooled” by factors other than brain damage, making it less reliable. NfL is more specific to the structural damage of neurons, giving a clearer picture of the actual injury.
A: It provides much-needed clarity. Instead of waiting months to see how a survivor recovers, doctors can use these early levels to inform families about what to expect and ensure the right rehabilitation starts immediately.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this cardiovascular health and cognition research news
Author: Justine Pinot
Source: European Society of Cardiology
Contact: Justine Pinot – European Society of Cardiology
Image: The image is credited to Neuroscience News
Original Research: The findings will be presented at the ESC Acute CardioVascular Care 2026
