Summary: A new study presented at ESC Acute CardioVascular Care 2026 indicates that measuring blood levels of neurofilament light chain (NfL) 48 hours after out-of-hospital cardiac arrest can accurately predict long-term cognitive outcomes. Researchers compared NfL with the commonly used biomarker neuron-specific enolase (NSE) and found that NfL showed markedly better diagnostic performance for forecasting cognitive impairment.
Higher NfL concentrations at 48 hours were strongly associated with lower scores on the Montreal Cognitive Assessment (MoCA) measured months later, while NSE levels displayed no meaningful relationship with later cognitive function. Early NfL measurement may allow clinicians to identify survivors at greatest risk of cognitive decline, focus diagnostic resources, personalize rehabilitation plans, and give clearer guidance to families.
Key Facts
- The NfL advantage: Neurofilament light chain measured early after hospital admission correlates inversely with longer-term measures of memory and thinking, making it a promising biomarker for brain injury after cardiac arrest.
- NSE limitations: Neuron-specific enolase, the current routine biomarker, did not show a reliable link to later cognitive outcomes in this study.
- Critical 48-hour window: Blood drawn two days after resuscitation provides an early signal of neuronal damage while many patients remain comatose, offering clinicians a useful prognostic window.
- Clinical implications: Routine early NfL testing could help prioritize advanced imaging and targeted rehabilitation for patients most likely to benefit.
Source: European Society of Cardiology
Study overview and context
After out-of-hospital cardiac arrest, the brain is especially vulnerable to injury from lack of oxygen and blood flow. Clinicians use a range of tests to assess damage and predict recovery, including biomarkers measured in blood. Neuron-specific enolase (NSE) is widely used, but its reliability is limited because levels can be influenced by factors other than brain injury. Neurofilament light chain (NfL) is a structural protein found in neurons that can enter the bloodstream when brain cells are damaged, offering a potentially more specific indicator of neuronal injury.
The research analyzed blood samples from participants in the Blood Pressure and Oxygenation Targets after Cardiac Arrest (BOX) trial. The included patients had been resuscitated from out-of-hospital cardiac arrest and were comatose on hospital admission. Investigators measured both NfL and NSE in samples taken 48 hours after the cardiac arrest and linked these values to cognitive outcomes using the Montreal Cognitive Assessment (MoCA) performed months later in a subset of survivors.
The central finding was a clear inverse correlation between NfL levels at 48 hours and MoCA scores at follow-up: higher NfL predicted poorer cognitive performance. By contrast, NSE measured at the same time point did not show a relationship with later cognitive function.
Dr. Martin Meyer from Rigshospitalet – Copenhagen University, Denmark, who presented the findings, highlighted that early NfL testing while patients are still hospitalized could help identify those at high risk of long-term cognitive impairment. That information can guide decisions about further diagnostics, intensive rehabilitation services, and timely discussions with patients’ families about expected recovery trajectories.
The investigators note that further work is necessary to validate NfL as a routine clinical tool and to standardize assay methods across laboratories. Analytical standardization and additional large-scale studies will be important before NfL testing becomes part of standard post-cardiac arrest care pathways.
Key Questions Answered:
A: In the setting of cardiac arrest, this study supports that measuring NfL 48 hours after the event provides a strong signal of neuronal injury and predicts later cognitive difficulties. The biomarker reflects structural damage that can translate into measurable impairments on cognitive tests.
A: NSE can be influenced by non-neurological factors, which reduces its specificity for brain injury. NfL is a neuronal structural protein and appears more closely linked to the extent of neuronal damage, offering clearer prognostic information.
A: Early NfL measurement could provide families with more accurate, earlier expectations about cognitive recovery, allow clinicians to prioritize rehabilitation resources, and support better-informed planning for long-term care needs.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by the editorial team.
- Additional context was added by staff to help explain the clinical implications.
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: Findings presented at ESC Acute CardioVascular Care 2026