What causes hearing loss at low and high frequencies with preserved hearing in mid frequencies?

Hearing Loss at Low and High Frequencies with Preserved Mid-Frequencies ("Cookie-Bite" Pattern)

The most important diagnosis to consider is Ménière's disease, which classically presents with low- to mid-frequency sensorineural hearing loss that can progress to involve high frequencies while initially sparing mid-frequencies, and requires immediate audiometric documentation and MRI evaluation to exclude retrocochlear pathology. 1, 2

Primary Differential Diagnosis

The "cookie-bite" or U-shaped audiometric configuration has several key etiologies:

Ménière's Disease (Most Common Acquired Cause)

• 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. 2
• The disease presents with episodic vertigo, fluctuating hearing loss in low- to mid-frequency ranges, tinnitus, and aural fullness in the affected ear. 1, 2
• Definite diagnosis requires two or more spontaneous vertigo attacks and audiometrically documented fluctuating low- to mid-frequency sensorineural hearing loss. 3
• The hearing loss typically starts unilaterally and may show asymmetry between ears. 2

Genetic Causes

• Certain genetic mutations can produce "cookie-bite" or U-shaped audiometric configurations with preserved mid-frequency hearing. 2
• The ACMG guidelines describe midfrequency (cookie-bite) loss as a recognized configuration pattern in genetic hearing loss. 1
• Approximately 70% of genetic hearing loss is nonsyndromic, with autosomal recessive inheritance (~80%) being most common. 1

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. 2
• Mid-octave frequencies should be measured if differences between standard frequencies exceed 20 dB. 2
• 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. 2

Imaging Requirements

• 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. 2
• When asymmetry is present (differences in pure tone average between ears >15 dB or word recognition scores >15%), MRI evaluation is warranted. 3
• CT of temporal bones is effective for detecting structural anomalies including enlarged vestibular aqueducts, Mondini malformations, and superior semicircular canal dehiscences. 4

Common Pitfalls to Avoid

Pre-Testing Essentials

• Always remove impacted cerumen before establishing a diagnosis, as it causes conductive hearing loss that confounds the clinical picture. 2
• Tuning fork testing should be performed to distinguish conductive from sensorineural components before triggering the sensorineural hearing loss evaluation pathway. 2

Pediatric Considerations

• 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. 2
• In pediatric patients with unilateral sensorineural hearing loss, 11% progress to bilateral loss, requiring close follow-up. 4
• CT temporal bones identified abnormalities in 33% of pediatric cases (20 of 61 scans), including enlarged vestibular aqueducts and Mondini malformations. 4

Timing Considerations

• Audiometric testing must be completed within 14 days of symptom onset for sudden hearing loss to enable accurate diagnosis and timely treatment decisions. 2
• Standard test-retest variability typically fluctuates by ±5 dB across frequencies, so changes <10 dB may not represent true threshold shifts. 5

Age-Related and Metabolic Factors

Diabetes Association

• 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. 2
• Proposed mechanisms include hyperglycemia and oxidative stress contributing to cochlear microangiopathy and auditory neuropathy. 2
• Risk factors include low HDL cholesterol, coronary heart disease, peripheral neuropathy, and general poor health. 2

Management Algorithm

Initial Conservative Management

• Dietary sodium restriction to less than 1500 mg daily as initial conservative management for Ménière's disease. 3
• Hearing aids are first-line management for serviceable hearing (typically word recognition scores >50%). 3

Referral Criteria

• Any atypical audiological test results showing a loss of more than 15 dB at 1000–8000 Hz require referral to an audiologist, auditory clinic, or ear, nose, and throat physician. 3
• Patients with conductive hearing loss or sensorineural loss that does not improve with hearing aids should be referred to an otolaryngologist. 6
• Referral to audiologist for amplification and hearing-assistive technology should occur as soon as hearing loss is identified. 3

Follow-Up Monitoring

• Audiometric follow-up should be obtained within 6 months of any treatment completion and at least annually thereafter. 3
• Quality of life assessment should be performed before and after therapeutic interventions to evaluate long-term outcomes. 3

Critical Warning

• Never rely solely on patient self-report of hearing status, as patients cannot accurately differentiate degree or type of hearing loss. 3