What causes low and high frequency hearing loss with normal hearing at mid frequencies?

Low and High Frequency Hearing Loss with Normal Mid-Frequency Hearing

The most likely cause of this "cookie-bite" or "U-shaped" audiometric pattern is Ménière's disease, which characteristically presents with fluctuating low- to mid-frequency sensorineural hearing loss, though the pattern you describe requires consideration of multiple etiologies including genetic causes, ototoxicity, and noise exposure. 1

Primary Differential Diagnosis

Ménière's Disease (Most Common)

• Ménière's disease is the classic cause of low-frequency sensorineural hearing loss that can progress to involve multiple frequencies while initially sparing mid-frequencies. 1
• The disease presents with episodic vertigo (lasting 20 minutes to 12 hours), fluctuating hearing loss in low- to mid-frequency ranges (≤2000 Hz), tinnitus, and aural fullness in the affected ear. 1
• Audiometry is mandatory for diagnosis—definite Ménière's disease requires documented fluctuating sensorineural hearing loss on at least one occasion before, during, or after a vertigo episode. 1
• The hearing loss typically starts unilaterally and may show asymmetry between ears (≥15 dB difference in pure-tone average or ≥15% difference in word recognition scores). 1

Ototoxicity from Cisplatin

• Cisplatin causes characteristic high-frequency hearing loss (4,000-8,000 Hz) that can extend to lower frequencies with cumulative exposure, potentially creating a pattern where mid-frequencies are relatively preserved initially. 2
• Ototoxicity occurs in up to 31% of patients receiving cisplatin 50 mg/m², with prevalence reaching 40-60% in children. 2
• The hearing loss is dose-related, cumulative, and may be unilateral or bilateral, with risk increased by prior cranial irradiation, age <5 years, concurrent ototoxic drugs (aminoglycosides, vancomycin), and renal impairment. 2
• Audiometric monitoring should be performed prior to each dose and for several years post-therapy. 2

Low-Frequency Noise Exposure

• Exposure to low-frequency noise (such as 0.063 kHz octave band noise at 90 dB SPL for 6 hours) can induce extensive hearing loss affecting both low and high frequencies while potentially sparing mid-frequencies. 3
• This pattern results from large-scale outer hair cell losses in both low- and high-frequency cochlear regions. 3
• Traffic noise contains significant low-frequency components that warrant consideration in occupational or environmental exposure histories. 3

Genetic/Hereditary Causes

• Certain genetic mutations can produce "cookie-bite" or U-shaped audiometric configurations with preserved mid-frequency hearing.
• These patterns are less common but should be considered in younger patients without other risk factors or in those with family history of similar hearing loss patterns.

Critical Diagnostic Workup

Mandatory Audiometric Testing

• Complete audiometry must include air and bone conduction thresholds at 250-8000 Hz, speech recognition thresholds, and word recognition scores to distinguish sensorineural from conductive components. 1, 4
• Mid-octave frequencies (750,1500,3000,6000 Hz) should be measured if differences between standard frequencies exceed 20 dB. 1
• Tympanometry is essential to rule out conductive components from otitis media with effusion, which can cause low-frequency hearing loss but would show abnormal middle ear function. 1

Imaging for Retrocochlear Pathology

• MRI with gadolinium of the brain and internal auditory canals is mandatory for all confirmed sensorineural hearing loss to exclude vestibular schwannoma and other retrocochlear pathology. 1, 4, 5
• This is particularly critical for asymmetric hearing loss patterns. 4, 5
• Auditory brainstem response testing may serve as an alternative screening tool when MRI cannot be performed. 5

Additional Testing for Ménière's Disease

• If Ménière's disease is suspected, vestibular testing may be indicated, though the diagnosis primarily rests on clinical criteria and audiometric documentation of fluctuating hearing loss. 1
• Serial audiograms are valuable to document fluctuation, which is pathognomonic for Ménière's disease. 1

Common Pitfalls to Avoid

Do Not Assume Normal Mid-Frequency Hearing Equals Normal Function

• Patients with high-frequency hearing loss may demonstrate severe speech processing deficits even in frequency regions where absolute thresholds appear normal (below 30 dB HL). 6
• These deficits result from suprathreshold auditory dysfunction caused by outer hair cell damage and cannot be predicted from the audiogram alone. 6
• Approximately half of listeners with high-frequency loss show extremely poor speech intelligibility in regions of clinically "normal" hearing. 6

Do Not Overlook Conductive Components

• Always remove impacted cerumen before establishing a diagnosis, as it causes conductive hearing loss that confounds the clinical picture. 4
• Tuning fork testing (Weber and Rinne) should be performed to distinguish conductive from sensorineural components before triggering the sensorineural hearing loss evaluation pathway. 1, 4
• Otitis media with effusion commonly causes low-frequency conductive hearing loss in children and can mimic sensorineural patterns if middle ear function is not assessed. 1

Do Not Delay Audiometric Confirmation

• Audiometric testing must be completed within 14 days of symptom onset for sudden hearing loss to enable accurate diagnosis and timely treatment decisions. 1, 4
• For Ménière's disease, hearing testing is recommended when symptoms persist for 3 months or longer, or immediately if significant hearing loss is suspected. 1

Do Not Ignore Extended High-Frequency Testing

• Standard audiometry only tests up to 8 kHz, but extended high-frequency audiometry (above 8 kHz) reveals hearing loss in approximately 74% of patients with subjectively normal hearing and tinnitus who have normal thresholds up to 8 kHz. 7
• The incidence of high-frequency or extended high-frequency hearing loss reaches 88% in patients with tinnitus and subjectively normal hearing at standard frequencies. 7

Age-Related Considerations

Diabetes and Metabolic Factors

• Hearing impairment in both high-frequency and low- to mid-frequency ranges is approximately twice as prevalent in people with diabetes compared to those without, after adjusting for age. 1
• Proposed mechanisms include hyperglycemia and oxidative stress contributing to cochlear microangiopathy and auditory neuropathy. 1
• Risk factors include low HDL cholesterol, coronary heart disease, peripheral neuropathy, and general poor health. 1

Pediatric Populations

• Children are particularly vulnerable to cisplatin ototoxicity (40-60% prevalence) and require audiometric monitoring before each dose and for years post-therapy. 2
• Otitis media with effusion is common in children and causes conductive hearing loss that must be distinguished from sensorineural patterns. 1