Audiological Progression and Treatment Outcomes in Superficial Siderosis: A 10-Year Retrospective Review of 46 Patients.

Abstract

Objective: To describe long-term hearing outcomes and evaluate the efficacy of interventions in patients with superficial siderosis (SS) of the central nervous system (CNS).

Study design: Retrospective case review.

Setting: Tertiary referral center.

Patients: Forty-six patients diagnosed with SS.

Interventions: Auditory examinations, including pure-tone audiometry, speech audiometry, and auditory brainstem response (ABR). Treatment modalities include surgical closure of the dural defect with postoperative iron chelator administration and cochlear implantation.

Main outcome measures: Pure-tone average (PTA), maximum speech discrimination score, and interpeak latency between ABR waves I and V.

Results: Sensorineural hearing loss (SNHL) was observed in 39 patients (84.8%), typically presenting in the fifth to sixth decades of life, and progressed gradually. Among the patients, SNHL was bilateral in 76.9%, with 56.7% showing asymmetry. The severity ranged from minimal to profound, with high-frequency loss being the most common (63.8%). Abnormal ABRs were observed in 82.6% of the ears. Long-term follow-up (median, 39 months) revealed hearing deterioration of ≥10 dB PTA in 25.9% of the ears. The long-term hearing prognosis can be predicted based on audiological changes within the first 12 months after the initial visit. Dural defect closure with iron chelator treatment seemed to prevent hearing deterioration in seven patients. Cochlear implantation showed limited effectiveness in three patients.

Conclusions: SS-related hearing loss can mimic age-related hearing loss, potentially leading to misdiagnoses. Clinicians should consider SS in middle-aged to elderly patients with progressive SNHL of unknown etiology and conduct comprehensive examinations, including speech audiometry, ABR, and T2*-weighted MRI, to facilitate an early diagnosis and appropriate management.