For many people living with systemic lupus (SLE), brain fog is one of the most frustrating symptoms to describe. Difficulty concentrating, forgetting familiar words, losing a train of thought, or feeling mentally slowed can interfere with work, school, relationships, and everyday responsibilities. Although these cognitive symptoms are widely recognized by people living with lupus and their healthcare providers, they have historically been difficult to measure in a standardized way.
A newly developed tool, the Lupus Brain Fog Severity Scale (LBFSS), aims to change that.
Developed through an international collaboration of researchers, clinicians, and people living with lupus, the LBFSS is the first lupus-specific patient-reported outcome measure (PROM) designed specifically to assess cognitive symptoms, commonly referred to as “brain fog.” Published in Lupus Science & Medicine in 2026, the LBFSS represents an important advancement in lupus research by providing a standardized way to measure patients’ experiences with cognitive symptoms.
Why Was the LBFSS Developed?
Brain fog is often described as one of the “invisible” symptoms of lupus. While laboratory tests and imaging can help evaluate many aspects of lupus, there has been no lupus-specific questionnaire designed to capture how cognitive symptoms affect daily life from the patient’s perspective.
Traditional neuropsychological testing remains an important part of evaluating cognitive function when appropriate, but these assessments may not fully reflect the day-to-day challenges experienced by people living with lupus. Researchers recognized the need for a tool that allows patients to report how brain fog affects their daily lives in a consistent, measurable way.
The LBFSS was developed to fill that gap.
Rather than replacing clinical evaluations or formal cognitive testing, the questionnaire complements them by providing valuable insight into the patient’s lived experience.
Developed With Input From the Lupus Community
One of the most unique aspects of the LBFSS is that people living with lupus helped shape every stage of its development.
Researchers first interviewed 147 individuals with SLE from 39 countries, asking them to describe how cognitive symptoms affected their daily lives. These interviews identified 21 different areas describing the experience of lupus-related brain fog.¹
Using a structured consensus process that included both lupus experts and patients, researchers refined those themes into 13 questionnaire items representing the symptoms considered most meaningful.
The questionnaire was then tested in 378 people living with lupus from 36 countries to determine whether it consistently measured cognitive symptoms.
The results demonstrated that the LBFSS has excellent internal consistency and strong construct validity, meaning the questionnaire reliably measures the cognitive symptoms it was designed to assess.¹
Why This Research Matters
The development of the LBFSS represents more than a new questionnaire. It reflects growing recognition that cognitive symptoms are a meaningful part of living with lupus and deserve to be measured alongside other aspects of disease activity.
Having a validated lupus-specific assessment tool may help researchers better understand the impact of brain fog in future studies and provide a standardized outcome measure for clinical research. It may also help healthcare providers better understand how cognitive symptoms affect an individual’s daily life and support more informed conversations during medical appointments.
Most importantly, the LBFSS validates what many people living with lupus have long reported: cognitive symptoms are real, can significantly affect quality of life, and deserve greater attention in both research and clinical care.
What the LBFSS Does and Doesn’t Do
Although the LBFSS is an exciting advancement, it is important to understand its role.
The questionnaire does not diagnose lupus, measure intelligence, or replace a comprehensive neurological or neuropsychological evaluation when one is needed.
Instead, it is a patient-reported assessment tool designed to help quantify cognitive symptoms from the patient’s perspective. Researchers hope its use will improve consistency across future lupus studies and continue advancing the understanding of lupus-related brain fog.
As additional research is conducted, the LBFSS may become an increasingly valuable resource in both research settings and clinical practice.
Talking With Your Healthcare Provider
If brain fog, memory concerns, or difficulty concentrating are affecting daily life, discuss these symptoms with your rheumatologist or healthcare provider. Cognitive symptoms are an important part of lupus and deserve to be part of routine conversations about disease management.
Patients may also wish to ask whether tools such as the Lupus Brain Fog Severity Scale (LBFSS) may help guide discussions about cognitive symptoms as research continues to evolve.
Medical Disclaimer: This article is intended for educational purposes only and should not be considered medical advice. The Lupus Brain Fog Severity Scale (LBFSS) is a research-based assessment tool and is not intended to diagnose lupus or replace a comprehensive medical evaluation. If cognitive symptoms such as memory problems, difficulty concentrating, or brain fog are affecting daily life, consult a rheumatologist or other qualified healthcare provider for individualized evaluation and treatment.
References
- Arnaud L, Touma Z, Jolly M, et al. International development of a lupus-specific instrument to assess cognitive symptoms in patients with SLE: Lupus Brain Fog Severity Scale (LBFSS) study. Lupus Science & Medicine. 2026;13:e002148. doi:10.1136/lupus-2026-002148.