Audiometric Configurations in Paget's Disease
Paget's disease of bone affecting the temporal bone most commonly produces mixed hearing loss (both conductive and sensorineural components), though pure sensorineural hearing loss is also frequently encountered, with bilateral progressive involvement being the typical pattern.
Types of Hearing Loss in Paget's Disease
The audiometric patterns in Paget's disease fall into two distinct categories:
Mixed Hearing Loss (Most Common Pattern)
- Mixed hearing loss represents the predominant audiometric configuration, occurring in approximately 61% of cases (11 of 18 patients with hearing loss in one series), characterized by both air-bone gaps and elevated bone conduction thresholds 1
- This pattern reflects dual pathology: conductive components from ossicular involvement and sensorineural components from cochlear/neural damage 1
- The conductive component typically results from ossicular ankylosis, stapedial footplate thickening, or middle ear ossicle involvement demonstrated on high-resolution CT 2
Pure Sensorineural Hearing Loss
- Pure sensorineural hearing loss occurs in approximately 39% of cases (7 of 18 patients), progressing without involvement of the transmission apparatus 1
- This pattern results from demineralization of the otic capsule, porosis pericochlearis, or petrous pyramid involvement 2
- Both conductive and sensorineural patterns can coexist in the same patient, and the types identified by audiometry include conductive, sensorineural, or both 3
Clinical Characteristics
Severity and Progression
- At least moderate hearing loss (≥40 dB HL) affects 55% of unselected Paget's patients, compared to 25% of age-matched controls 4
- Severe-profound hearing loss (≥60 dB HL) occurs in 33% of Paget's patients (25 of 75 patients) 4
- The hearing loss is characteristically bilateral and progressive, representing the most frequently encountered complication of Paget's disease 3
Laterality and Symmetry
- Bilateral involvement is the rule rather than the exception in Paget's disease affecting hearing 3
- The progressive nature means serial audiometry demonstrates worsening thresholds over time despite treatment 2
Anatomical Correlates on Imaging
High-resolution CT demonstrates specific structural abnormalities that correlate with audiometric findings:
- Middle ear ossicle involvement (28% of cases) contributing to conductive components 2
- Petrous pyramid involvement (56% of cases) affecting sensorineural function 2
- Demineralization of the otic capsule (40% of cases) causing sensorineural loss 2
- Porosis pericochlearis (32% of cases) affecting cochlear function 2
- Stapedial footplate thickening (16% of cases) causing conductive loss 2
- Narrowing of the external auditory meatus (48% of cases) potentially contributing to conductive components 2
Important Clinical Caveats
Treatment Limitations
- Bisphosphonate therapy does not improve or prevent progression of hearing loss despite improving bone turnover markers and scintigraphy findings 2
- Surgical interventions (stapes mobilization, stapedectomy) have produced frankly disappointing long-term results and are not recommended 1
- The lack of treatment efficacy likely reflects the long duration of disease and established structural damage by the time of diagnosis 1
Screening Considerations
- The HHIE-S questionnaire with a score >8 effectively screens for moderate hearing impairment in Paget's patients, with an odds ratio of 5.1 for detecting ≥40 dB HL 4
- However, 41% of Paget's patients perceive moderate-severe hearing handicap compared to none of age-matched controls, indicating significant underreporting 4
- Formal audiometry remains essential as bisphosphonate treatment may improve symptoms without improving hearing thresholds 2