The goal of this observational case-control study is to evaluate the relationship between temporal bone computed tomography (CT) findings, bone mineral density (BMD), and audiological parameters in adults diagnosed with otosclerosis. The main questions it aims to answer are:

Is there a correlation between temporal bone CT density values and the severity of hearing loss in otosclerosis? Do bone mineral density and serum vitamin D levels differ between otosclerosis patients and individuals without otosclerosis? Researchers will compare patients diagnosed with otosclerosis to a control group without otosclerosis to determine if CT-based density variations are associated with disease severity and systemic bone metabolism markers.

Participants who have already had a temporal bone CT scan as part of their routine clinical evaluation will undergo:

Bone mineral density (BMD) assessment via dual-energy X-ray absorptiometry (DEXA) Serum vitamin D level measurement Audiological testing, including pure tone audiometry and speech discrimination tests This study aims to improve the diagnostic and prognostic understanding of otosclerosis by integrating imaging, metabolic, and audiological data.

Inclusion Criteria (Otosclerosis Group):

• Adults diagnosed with otosclerosis based on audiological and clinical assessment
• Patients with available high-resolution CT scans and audiological data
• Individuals who have undergone stapedectomy or stapedotomy surgery
• Availability of bone mineral density and serum vitamin D data

Inclusion Criteria (Control Group):

• Patients without otosclerosis but with temporal CT imaging for other indications
• No history of conductive or mixed hearing loss
• Availability of BMD and vitamin D data

Exclusion Criteria:

• History of primary metabolic bone diseases (osteoporosis, Paget's disease)
• Use of medications affecting bone metabolism (bisphosphonates, corticosteroids)
• History of chronic otitis media or prior ear surgeries
• Patients who received head and neck radiotherapy

The study population consists of adult patients evaluated at the Otorhinolaryngology Department of Hacettepe University for hearing-related concerns. Participants will be selected from individuals who have undergone audiological testing and temporal bone computed tomography (CT) imaging as part of their clinical assessment.

The study includes two groups:

Otosclerosis Patients (Study Group): Adults diagnosed with otosclerosis based on clinical, audiological, and radiological criteria. These patients have undergone or are scheduled for stapedectomy or stapedotomy surgery.

Non-Otosclerosis Patients (Control Group): Individuals who have no clinical or audiological signs of otosclerosis but have undergone temporal bone CT for unrelated reasons, such as investigation of other otologic symptoms (e.g., vertigo, tinnitus, or trauma assessment).

Participants will primarily be recruited from tertiary care settings within the hospital, ensuring access to specialized diagnostic and surgical inter