Efficient assessment of brain fog and fatigue: Development of the Fatigue and Altered Cognition Scale (FACs)

Abstract

Debilitating symptoms of fatigue and accompanying “brain fog” are observed among patients with various chronic health conditions. Unfortunately, an efficient and psychometrically sound instrument to assess these co-occurring symptoms is unavailable. Here, we report the development and initial psychometric properties of the Fatigue and Altered Cognition Scale (the FACs), a measure of self-reported central fatigue and brain fog. Traumatic brain injury (TBI) was chosen to model and develop the FACs due to research team expertise and established links between TBI and the symptom complex. Potential items were generated by researchers and clinicians with experience treating these symptoms, drawing from relevant literature and review of patient responses to measures from past and current TBI studies. The 20 candidate items for the FACs—ten each to assess altered cognition (i.e., brain fog) and central fatigue–were formatted on an electronic visual analogue response scale (eVAS) via an online survey. Demographic information and history of TBI were obtained. A total of 519 participants consented and provided usable data (average age = 40.23 years; 73% female), 204 of whom self-reported a history of TBI (75% reported mild TBI). Internal consistency and reliability values were calculated. Confirmatory factor analysis (CFA) examined the presumed two-factor structure of the FACs and a one-factor solution for comparison. A measurement invariance test of the two latent constructs (altered cognition, fatigue) among participants with and without TBI was conducted. All items demonstrated normal distribution. Cronbach’s alpha coefficients indicated good internal consistency for both factors (α’s = .95). Omega reliability values were favorable (α’s = .95). CFA supported the presumed two-factor model and item loadings which outperformed the one-factor model. Measurement invariance found the two-factor structure was consistent between the two groups. Implications of these findings, study limitations, and potential use of the FACs in clinical research and practice are discussed.

Prevalence of fatigue and cognitive impairment after traumatic brain injury

“…A full description of the questionnaire and its development has been previously published [37]. In brief, the research team created 20 relevant questions based on clinical experience and existing literature for participants to self-assess fatigue and brain fog (see S1 File for question flow).…”

“…Participants then completed a modified version of the previously validated Ohio State University TBI Identification Method (OSU TBI-ID) to collect further information about lifetime history regarding the type and severity of TBI [10]. As previously reported, the median time to complete the questionnaire for non-TBI individuals was 3.7 minutes, and TBI individuals took a median of 6.2 minutes due to additional TBI-related questions [37].…”

“…Although persistent FAC symptoms are known to develop in a subset of individuals following TBI, it is not clear how the occurrence and severity of these symptoms vary in the general population, among individuals with a range of TBI severity, or following other clinical conditions. In order to study BIAFAC and other similarly manifesting clinical conditions, we developed the Fatigue and Altered Cognition Scale (FACs) as a sensitive and specific digital questionnaire to evaluate self-reported comorbid symptoms of fatigue and cognitive impairment [37]. The FACs was validated by comparing responses from research participants with a history of TBI to those without a TBI history.…”

The Fatigue and Altered Cognition Scale among SARS-CoV-2 Survivors: Psychometric Properties and Item Correlations with Depression and Anxiety Symptoms

“…The 20-item Fatigue and Altered Cognition Scale [16] contains 10 items to assess brain fog (labeled as "altered cognition") and another 10 to assess central fatigue. Participants provided their responses to each item using an electronic visual analog rating (eVAS) scale, known for its simplicity in both administration and scoring [30].…”

“…In the present study, we examine the psychometric properties of Fatigue and Altered Cognition (FACs) [16] among COVID-19 survivors. The FACs was developed to efficiently assess symptoms of co-occurring brain fog and central fatigue among persons with chronic health conditions and its factor structure and item integrity were demonstrated among respondents with and without traumatic brain injury (TBI) [16]. The items on the FACs are formatted with digital visual analog response scales that can be administered with electronic devices in clinical and research settings.…”