A Review of Adult-Onset Hearing Loss: A Primer for Neurologists

Abstract

Purpose of the review: The goal of this review is to highlight current approaches to diagnosis and treatment for adult-onset hearing loss in patients likely to present to a neurologist's office. The review will discuss primary and secondary causes of acute and chronic hearing loss, and will discuss common situations that can be managed by a neurologist as well as situations that require immediate care and referral for further management by an otolaryngologist-head and neck surgeon.

Recent findings: Hearing screening assessments using mobile applications and tablet devices are now available and can be integrated into many clinical practice settings, including in the evaluation of hearing concerns related to various neurological pathologies. For patients presenting with a sudden worsening in hearing, bedside evaluation, including with objective measures of hearing, can inform neurologists about diagnosis and subsequent management. For patients who present with gradual worsening in hearing, particularly those related to neurologic disorders, hearing care can be an important adjunct to ongoing neurologic care. More commonly encountered, age-related hearing loss is highly prevalent among older adults and may affect overall neurological assessment, including neurocognitive testing, as well as patient-provider communication, patient satisfaction, and care outcomes. Hearing loss is increasingly recognized as a potentially modifiable risk factor for dementia. Neurologists can support the hearing health of their patients through the routine use of communication strategies and by integrating simple, low-cost technology with their current clinical practices.

Summary: Both acute and chronic hearing loss can be a symptom of many conditions managed by neurologists. Few conditions are emergent, requiring immediate referral to and treatment by an otolaryngologist-head and neck surgeon. Despite the range of hearing interventions available, including hearing aids, over-the-counter devices, and aural rehabilitation, hearing loss is a common and under-treated chronic health condition. By promptly addressing a patient's hearing concerns, neurologists can improve patients' awareness of the deficit and support the overall importance of maintaining sensory health across the life course.

Keywords: Hearing loss; age-related hearing loss; aural rehabilitation; cochlear implant; hearing aids; mobile hearing screening.

Figure 1.

Flowsheet differentiating multiple causes of hearing loss. The onset and chronicity of hearing loss is a critical starting point in understanding whether urgent action is needed, such as in the setting of suspected stroke or sudden sensorineural hearing loss. For hearing loss that has been present for months to years, differentiating whether the loss is primarily symmetric or asymmetric is another point that should prompt consideration of referral and further evaluation. Regardless of the underlying cause of hearing loss, including age-related hearing loss, assessment and interventions can and should be offered.

Figure 2.

An audiogram measures a patient’s auditory threshold responses with pure-tone stimuli across a range of sound frequencies that are important for human communication, typically 250 Hz to 8000 Hz. The threshold is the sound intensity level at which an individual detects the tone 50% of the time. Hearing loss severity is referenced to a healthy population (A). An audiologist generally assesses both air-conducted (circles) and bone-conducted sound (brackets). Both results are graphed with frequency on the x-axis, measured in Hertz (Hz), and the threshold for sound intensity on the y-axis, measured in decibels hearing level (dB HL). B) Sensorineural hearing loss can be differentiated from C) conductive hearing loss by the presence of a air-bone gap in which a difference exists between air-conduction and bone-conduction thresholds. Some patients with both conductive and sensorineural components of hearing loss in the same ear are said to have mixed hearing loss D). In patients with age-related hearing loss (B), an audiogram typically displays symmetric hearing loss primarily at higher frequencies between 2000 and 8000 Hz¹⁷. Only right ear data is graphed for simplicity.