# Assessing Gluten-Induced Brain Fog in a Non-celiac Patient: A Case Report

## TL;DR

A non-celiac patient experienced cognitive issues linked to gluten, which were objectively measured using EEG and P300 components.

## Contribution

This case report demonstrates the use of ERP testing to objectively assess gluten-related cognitive symptoms in non-celiac individuals.

## Key findings

- The patient showed a suppressed P300 component after gluten exposure, correlating with self-reported brain fog.
- After a gluten-free diet, the P300 normalized and brain fog symptoms resolved.
- EEG with P300 can be a useful tool in evaluating cognitive concerns related to dietary factors.

## Abstract

While gluten-induced brain fog is frequently reported in individuals with celiac disease, it is uncertain whether people without classic gastrointestinal symptoms of celiac may also experience similar gluten-related cognitive issues. These types of subjective complaints are difficult to quantify in clinical practice, but electroencephalography (EEG) with event-related potentials (ERPs) can be useful in identifying cognitive disturbances. The case we present here is of a 28-year-old male who reported mild cognitive symptoms associated with gluten exposure, not previously objectively evaluated. His evaluation included reaction time, trail-making, and auditory ERP assessments - modalities sensitive to conditions associated with cognition. His initial test was performed after three weeks on a normal gluten-containing diet. After this gluten exposure, the patient reported “brain fog,” which was supported by a low P300, the cognitive component of the ERP, even though he still tested strongly in reaction time and trail making. The patient was tested again after three weeks on a gluten-free diet. After eliminating gluten, the patient reported no brain fog, and this was supported by a P300 that was no longer suppressed. While this single case study cannot address causation, the ERP deficits observed in this patient were consistent with the reported “brain fog.” Objective modalities such as EEG with P300 can be readily added to the clinical assessment to aid clinicians in testing hypotheses, including situations where elimination diets are considered to address cognitive concerns.