0182 Deriving Lexicon from Community Word Usage: A Social Listening Analysis of “Brain Fog” in Central Disorders of Hypersomnolence

Abstract Introduction The term "brain fog" lacks clear definition and is likely interpreted differently across conditions, between individuals, and between patients and clinicians. Using social listening, we analyzed 14 years of central disorders of hypersomnolence (CDH) community discussions to reveal authentic patient experiences and evolving lexicon of brain fog for the sleep community. Methods We analyzed 554,312 documents (posts/comments) from 2 subreddits (r/narcolepsy and r/idiopathichypersomnia) and a private Facebook group (PWN4PWN) using vector semantics to determine words often used in the context of “brain fog” as well as phrases used in a similar way to “brain fog”. Usage of these phrases was compared over two timespans: historical (2011-2015) and recent (2017-2025). Documents were also run through a proprietary analytics engine that recognizes mentions of clinical findings as well as their relation to the author (eg, actually experienced, hypothetical) in social media text. Results Analysis revealed context words most associated with “brain fog” were “clears”, “forgetfulness”, “lifted”, “memory”, “fatigue”, “drunkenness”, “dissociation”, “concentration”, “cognitive”, and “constant”. The top 40 similar phrases included synonyms (eg, “fog”, “mental fog”, “fogginess”) and symptom descriptions like “difficulty concentrating”, “inability to focus”, “poor memory”, “forgetfulness”, and “lethargy”. The yearly proportion of documents using “brain fog” and related “fog” words grew steadily until 2017 and has been consistently >1% of documents thereafter. The proportions of documents using “brain fog” and “fog” has significantly increased between the historical and recent period, while those using “memory loss”, “memory problems”, and “mental fog” have significantly decreased (all P< 0.02). Associated clinical findings included Memory impairment, Memory dysfunction, and Impaired concentration. Conclusion This social listening analysis demonstrates that these online CDH communities primarily associate “brain fog” with memory impairment. The community’s linguistic evolution captured across 14 years suggests the community organically develop shared language that evolved from memory-related phrases to “brain fog.” The methodology delivers real-world evidence at community scale, offering unique insights into authentic patient experiences that are difficult to capture through traditional research purposes. Support (if any) Avadel Pharmaceuticals