OBJECTIVE:Fatigue is among the most disabling symptoms across neurological and postinfectious conditions and is a defining feature of long COVID, yet objective neurophysiological markers remain scarce. Auditory sensory gating, indexed by P50 suppression, has been proposed as a correlate of cognitive fatigue in multiple sclerosis, but its relevance in long COVID is unclear. Additionally, we compared the utility of the Beck Depression Inventory-II and Beck Depression Inventory-Fast Screen (BDI-FS) in this fatigued population. METHOD:Seventy-one individuals with long COVID-related fatigue completed questionnaires assessing fatigue (Modified Fatigue Impact Scale) and depressive symptoms (BDI-FS). Auditory sensory gating was assessed using a paired-click electroencephalography paradigm. Auditory sensory gating was assessed using a paired-click electroencephalography paradigm. Associations between cognitive fatigue, sensory gating, and depressive symptoms were examined using correlational analyses and two hierarchical regression models. RESULTS:Reduced P50 suppression was associated with higher Modified Fatigue Impact Scale cognitive scores (τ = -.173, p = .037). Cognitive fatigue correlated with depressive symptoms measured by the Beck Depression Inventory-II (τ = .239, p = .005), but not by the BDI-FS (τ = .131, p = .135). Neither depression measure correlated with sensory gating. P50 suppression accounted for unique variance in cognitive fatigue beyond demographics and depressive symptoms. CONCLUSIONS:Auditory sensory gating shows a small but meaningful association with cognitive fatigue in long COVID and contributes uniquely beyond depressive symptoms. The BDI-FS demonstrated less symptom overlap, supporting its suitability for depression screening in fatigued populations. These findings underscore the importance of distinguishing fatigue related from affective symptoms and suggest sensory gating as a promising transdiagnostic target in fatigue research. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
