Altered auditory brainstem responses are post-acute sequela of SARS-CoV-2 (PASC)

Area of Science:

• Neuroscience
• Audiology
• Infectious Diseases

Background:

• Post-acute Sequela of SARS-CoV-2 (PASC), or Long-COVID, is characterized by persistent subjective symptoms like brain fog and cognitive fatigue.
• Auditory issues, including tinnitus and impaired hearing in noise, are reported in PASC, but their link to cognitive symptoms remains unclear.
• Objective electrophysiological measures, such as the Auditory Brainstem Response (ABR), can assess auditory processing and may offer insights into PASC-related changes.

Purpose of the Study:

• To investigate the relationship between Auditory Brainstem Response (ABR) findings and cognitive symptoms in individuals with PASC.
• To determine if objective ABR measures can predict PASC status and correlate with subjective cognitive fatigue.

Main Methods:

• Eighty-two participants (37 PASC, 45 controls) underwent audiometry and ABR testing with varying click rates.
• ABR wave V latency and V/I amplitude ratios were analyzed.
• Correlation analyses were performed between ABR measures, cognitive fatigue scores, tinnitus frequency, and PASC status.

Main Results:

• PASC subjects reported higher rates of tinnitus, anxiety, depression, and cognitive fatigue.
• Increased ABR wave V latency at faster click rates was observed in PASC subjects and correlated with cognitive fatigue.
• Elevated ABR V/I amplitude ratios, indicative of central gain, were significant predictors of PASC classification and cognitive fatigue in younger PASC individuals.

Conclusions:

• PASC may affect the central auditory pathway, leading to slower conduction and altered neurophysiological responses, mimicking aspects of aging.
• ABR measures, particularly wave V latency and central gain, show promise as objective indicators of cognitive fatigue in PASC.
• Tinnitus frequency is also associated with increased subjective cognitive fatigue in PASC patients.