Introduction

The impact of COVID-19 on neurosensory systems remains insufficiently understood. There have been reports of tinnitus, vertigo, and sensorineural hearing loss occurring after COVID-19 infections. However, a clear correlation and causation between these conditions and the virus have not been established [1]. Understanding COVID-19-Related Tinnitus: Emerging Evidence and Implications,” Science & Research News. Tinnitus Today, 2023. Early studies noted cases of newonset tinnitus in conjunction with hearing loss following COVID-19 infection [2-5]. Subsequent case reports [6-8] and comprehensive studies further indicated its frequent occurrence among affected patients [9, 10]. Some cases have been reported where patients experienced changes in hearing loss and perceived loudness [11, 12].

The relation between tinnitus and hyperacusis is notably strong, with approximately 86% of hyperacusis patients also experiencing tinnitus [13], and around 27% to 40% of tinnitus patients displaying hyperacusis symptoms [14, 15]. Hyperacusis in tinnitus has been associated with younger age, greater tinnitus-related mental and general distress, and increased pain disorders and vertigo [16]. In addition, individuals with persistent tinnitus commonly experience an exacerbation of their symptoms in response to psychological stress or emotional strain [17, 18], and the circumstances brought about by the pandemic can be regarded as a stress-inducing factor [19-21]. During the recent phase of the pandemic, many people noted heightened sensitivity to sounds on the day of vaccination or during the first week after vaccination [22]. Studies like Erinc, et al. [23] reported the relationship of tinnitus and hyperacusis in patients affected by COVID-19 infection. In this study, the notable increase in hyperacusis is related to stress, but the factor of vaccination changes in the auditory system was not considered.

Driven by two research questions, this case study outlined herein examined (i) if COVID-19 vaccination impacts pre-existing hearing loss, tinnitus, and hyperacusis and (ii) whether the pandemic-induced circumstances affect existing tinnitus or hyperacusis. To address these questions, investigated the influence of COVID-19 and vaccination on a subject with chronic tinnitus. Gathered and compared data related to hearing tinnitus and hyperacusis from a subject before and two years after the start of the pandemic.

This study presents a unique case of severe change in the sensitivity of hearing, tinnitus and hyperacusis post first dose of COVID-19 vaccine.

Case Presentation

A female subject aged 47 years has reportedly been experiencing bilateral tinnitus for the preceding three decades. Subject history indicated recurrent middle ear infections and developed scarring on their tympanic membranes due to frequent air travel during childhood. By their adolescent years, these ear infections ceased. Their initial recollection of a hearing assessment indicated minor hearing loss. While lacking official records, it is noteworthy that mild, intermittent tinnitus persisted since their teenage years-an aspect consistently communicated to audiologists. This tinnitus, typically bilateral, held limited significance to the subject.

A report from 2014 stated that the subject reported occasional tinnitus in her right ear only. In 2008, subject had her middle ear infection and was diagnosed with labyrinthitis in 2010. The subject experienced dizziness during this period. Her pure-tone audiometry revealed a symmetrical bilateral mild to moderate Sensorineural Hearing Loss (SNHL) Table 1 with absent reflexes and good speech scores. In 2016, despite discussions about hearing aids, the subject chose not to proceed at that juncture.

Table 1. Pure tone audiometry and speech scores of the patient from the year 2014 to 2023

Audiological reports from 2017 Table 1 indicate mild to moderate SNHL and reported intermittent use of hearing aids, evolving into more regular usage. In mid-late 2019, the subject reported vertigo issues and received a diagnosis of Benign Paroxysmal Positional Vertigo (BPPV) and engaged in physiotherapy, resulting in its amelioration Table 1.

In the context leading up to October 1, 2021 (the day of their second Pfizer vaccination) and from 2021, the subject’s contemporaneous diary facilitated the documentation of their ear health trajectory:

May-June: There was a reported Eustachian tube dysfunction which prompted a sense of aural obstruction. Allergy tests revealed environmental sensitivities (like dust, cats). A referral to an otolaryngologist ensued.

July 12, 2021: The Subject experienced hyperacusis for the first time in the left ear (which might be associated with the existing middle ear issues).

July 13, 2021: Consulted an otolaryngologist with no documented report. The otolaryngologist noted no definitive treatment for the eustachian tube dysfunction or hyperacusis, anticipating their spontaneous resolution over time. By July 19, hyperacusis abated, and minimal discomfort prevailed for several weeks.

August 12, 2021: An annual hearing evaluation indicated no deterioration from the prior year Table 1.

September 4, 2021: Received the first dose of the Pfizer vaccine with minimal apprehension.

September 9, 2021: Hyperacusis re-emerged in the left ear alongside pronounced “roar” type tinnitus, persisting through most of September and continuing to the present.

October 1, 2021: received her second Pfizer vaccination in the left arm. On October 2, there is unequivocal evidence of an exceptionally intense episode of tinnitus in the left ear in 2021distinct from any previous experiences. The onset of tinnitus commenced at around 4:30 PM, a moment firmly etched in their memory due to its profound impact. The subject noticed a significant increase in tinnitus in her left ear, reaching an almost unbearable level, accompanied by a sudden deterioration in her hearing. She consulted an ENT on October 8 2021, subject was told her tinnitus and hyperacusis might be due to anxiety. An MRI was recommended, with no hearing tests deemed necessary given the recent August evaluation. However, the MRI was deferred due to concerns related to noise. The subject then leaned towards naturopath consultation which recommended a regimen of herbal and mineral supplements, including high-dose magnesium. During this week, subject perceived the sound as being so loud that subject worried it might be causing damage to her hearing, much like any other intense noise would. The episodes lasted for 3-8 hours each day and occur regularly. The subject reported the hyperacusis experienced after receiving the vaccine has profoundly impacted her daily life.The subjects now find tolerating everyday sounds, such as stacking plates, the TV, or the hair dryer, extremely challenging. The condition has caused weeks of insomnia, even with the aid of sleep medication, leading to feelings of depression. As a result of heightened sensitivity to sound, the subject has been unable to socialize or leave the house except for essential activities like attending her children’s school events. From January 2022, the subject was on medication for anxiety management (10mg Entrip).

June 2022: The Subject visited an audiologist with ongoing concerns, leading to the suggestion of seeking a second opinion from another ENT specialist. Her left ear showed a significant deterioration at low frequencies with reduced speech scores Table 1. The second ENT acknowledged hearing loss and tinnitus. Requested an MRI for further evaluation, and no anomalies emerged from the imaging. The subject was then on Cognitive Based Therapy to improve tinnitus and hyperacusis. Over time, the extreme tinnitus in her left ear gradually diminished to a more tolerable level. However, it still fluctuates, and the subject now experiences three different constant ‘tones’ of bilateral tinnitus. Her hearing has not changed per March 2023 audiogram values Table 1. In May 2023, the subject contracted COVID-19 and noticed a slight increase in tinnitus (though not as severe as in October 2021), but there have been no significant changes since then.

August 2023: Current hyperacusis in the subjects left ear remains constant, and the tinnitus levels are a little closer to pre-vaccination levels but do still spike at times and can become overwhelming. The subject has been consulting a psychologist since 2021 for the management of the ongoing hyperacusis and hearing loss. Since July 2023, the subject has been able to tolerate using hearing aids occasionally at a reduced volume.

COVID-19 vaccination effects on Tinnitus, Hyperacusis and Speech Understanding

The subject was asked to rate the questions Figure 1 on tinnitus, hyperacusis, and speech understanding before COVID-19 vaccination, after COVID-19 vaccination, and their status as of August 25, 2023. The rating scale was from 0 to 10, where 0 is no effect and 10 is extreme. Questions were adapted for different standardized questionnaires for tinnitus and hyperacusis. Figure 1 illustrates the results of the rating. The comparison of the effect of COVID-19 vaccination (i) before to immediately after vaccination results showed an increase in all the aspects of tinnitus- loudness, severity and anxiety from 2 to 10, and pitch changed from 3 (low) to 8 (high). As time passed, as of August 25 2023, the ratings lowered i.e., loudness, severity, and anxiety from 10 to 7, and pitch changed from 8 to 7. (ii) For hyperacusis, the change from before to immediately after COVID-19 vaccination was from median 1 to 7 and reduced to 5 as of Aug 2023. (iii) Speech Understanding ability followed a similar trend before and after vaccination, rating showed a change median 3 to 8. The effect remained the same for the speech’s clarity, rated as 8. Understanding group/ conversations has slightly improved.

Figure 1: Subjective rating of (i) Tinnitus, (ii) Hyperacusis and (iii) Speech Understanding ability of the patient before COVID-19 vaccination, immediately after COVID-19 vaccination and as of 25 Aug 2023 (current status). Rating scale: 0-10 scale (0 = No effect, 10 = extremely).

Regarding hearing impairment, during the intense bout of tinnitus in 2021, the subject’s hearing was diminished and compounded by the struggle to hear beyond the tinnitus noise. Gradually, the tinnitus was reported to subside to a more bearable level, making it less challenging to disregard. The hearing loss’s substantial effects persist on speech perception and on her lifestyle. For instance, subjects reported watching TV without subtitles is a challenge for her despite using hearing aids or returning to the cinema seems implausible, too loud, and wouldn’t understand.

To understand the effect of hyperacusis on the subject’s functional, social, and emotional wellbeing, ‘Tinnitus Practitioners Association MODIFIED Khalfa Hyperacusis Questionnaire [24] was administered. A questionnaire was administered before and after COVID-19 vaccination. The results showed a severe effect on all three categories after COVID-19 vaccination condition compared to normal before vaccination results Table 2.

Table 2. Showing responses of  Modified Khalfa Hyperacusis Questionnaire [23] for before COVID-19 vaccination and after COVID-19 vaccination. The questionnaire contains 7 Functional, 6 Social, and 7 Emotional questions. Rating scored as Yes as 5, Sometimes as 2, No as 0. Loudness Sensitivity Handicap Scale (LSHS) for before COVID-19 vaccination indicated normal sensitivity and after COVID-19 vaccination indicated severe loudness sensitivity

Discussion

Numerous reports have been published, sparking controversy and debate surrounding the potential effects of COVID-19 vaccination on tinnitus and hyperacusis [25]. Notably, there exists a body of extensive studies [26-29]. that supports and delves into this phenomenon. In addition to the discussions on auditory issues, various research studies have highlighted a notable increase in psychological challenges, including anxiety, depression, and other mental health issues, throughout the course of the COVID-19 pandemic [30]. In this case presentation, the subject reported experiencing stress and anxiety post onset of tinnitus and experienced hyperacusis. The association between stress and anxiety during the pandemic has been suggested to contribute to tinnitus in some individuals [31]. The key observation in this particular case study is that COVID-19 could potentially exacerbate pre-existing conditions, leading to the advertising of the existing tinnitus and sudden relapse of hyperacusis. The subject reported experiencing tinnitus on July 21, 2021 and relapsed after the second vaccination on October 1, 2021. The tinnitus experienced a notable surge in severity, pitch, and loudness [32].Over time, there seems to be improvement in medical and psychological management for hyperacusis and hearing loss. The hyperacusis became more severe, leading to negative impacts. Tinnitus and hyperacusis have significantly compromised subjects’ lifestyle and speech comprehension abilities. Their description indicates profound disturbances in daily life.

These poignant encounters emphasize the urgency of timely assistance and support for individuals affected by tinnitus. Ongoing research aims to elucidate the precise mechanisms that establish a connection between COVID-19 vaccination and the development of tinnitus or hyperacusis. Healthcare practitioners must remain vigilant in recognizing and documenting instances of tinnitus and hyperacusis in patients with a history of COVID-19. Swift intervention, in collaboration with specialists in audiology, as well as the provision of empathetic care, play a pivotal role in mitigating the adverse effects of tinnitus on patients’ overall well-being. During this ongoing inquiry, healthcare providers should stay attuned to the evolving evidence surrounding tinnitus concerning COVID-19.