PP507 - Auditory Evoked Potentials in Individuals after COVID-19 Infection

Abstract:
This study investigated pure-tone audiometry, speech audiometry, acoustic immittance measures, auditory brainstem response (ABR), and long-latency auditory evoked potentials (LLAEP) in post-COVID-19 patients aged 19 to 58 years. They had more abnormal results in pure-tone audiometry (predominantly bilateral sensorineural hearing loss), ABR, and LLAEP. Further studies are needed to investigate such patients’ peripheral and central auditory pathways.

Summary:
Rationale/purpose: Despite being mainly a respiratory disease, COVID-19 is currently known to cause harm and sequelae in various systems and organs, including long-term cognitive deficiencies. Auditory-evoked potentials reflect the neuroelectric activity of the auditory pathway from the brainstem to the cortical and subcortical structures, whose functions include discrimination, integration, and attention. Thus, they can objectively identify both sensory and cognitive changes. Given the strong relationship already established in the literature between viral infections and auditory system changes, the objective of this study was to investigate the possible impacts of COVID-19 infection on the peripheral and central auditory pathways.

Method: The study assessed 33 confirmed post-COVID-19 patients aged 19 to 58 years (eight men and 25 women), without previous hearing complaints or risk factors for hearing loss. The following procedures were performed in all individuals: pure-tone audiometry, speech audiometry, acoustic immittance, auditory brainstem response (ABR), and long-latency auditory evoked potentials (PEALL). They also had their medical history surveyed and answered a specific questionnaire on COVID-19 infection.

Results: 12 (36.3%) individuals had some degree of impairment in audiometry examinations – 11 with sensorineural and one with mixed hearing loss. In ABR, 16 individuals (48.4%) had abnormal results, with increased absolute latencies in wave I in one subject (3%), wave III in 11 subjects (33.3%), and wave V in four subjects (12.1%). There were also increased values in interpeak interval I-III in three subjects (9%), interpeak interval III-V in six subjects (18.1%), and interpeak interval I-V in five subjects (15.1%). Delayed latencies were found in LLAEP in 27 subjects (81.8%) in the following components: P2 in four subjects in the right ear (12.1%) and nine subjects in the left ear (27.3%); N2 in 26 subjects in the right ear (78.8%) and 24 subjects in the left ear (72.7%); and P300 in three subjects in the right ear (9.1%) and two subjects (6.1%) in the left ear. Most changes were related to N2, which is considered mixed, due to exogenous and endogenous factors – i.e., related to both sensory and cognitive aspects of hearing. Regarding collected history data, no subject reported previous hearing complaints, but three (9%) of them reported their hearing worsened after the infection, seven (21.2%) reported tinnitus, and 20 (60.6%) reported memory difficulties after the infection. Only seven individuals (21.2%) reported using ototoxic drugs during treatment, five of whom had abnormal results in peripheral and central assessments.

Conclusions: Given the data on self-reported post-COVID-19 hearing complaints and the high index of changes found in both peripheral and central audiological assessments, there are indications that the new coronavirus can impair the hearing system as a whole. These results must be regarded as preliminary due to the many variables involved in the study. Nonetheless, it is seemingly essential to audiologically assess post-COVID-19 patients. Moreover, it is greatly important to conduct further research on the topic, especially longitudinal studies, to better understand the post-COVID-19 effects on hearing.