Auditory profile in superficial siderosis of the central nervous system: a prospective study.

OBJECTIVE

To identify auditory pathology resulting from superficial siderosis of the central nervous system (SSCN), auditory site of lesion, and a clinical profile for differential diagnosis and development of recommendations.

STUDY DESIGN

Prospective study.

SETTING

Academic clinical center.

PATIENTS

Ten participants with SSCN (the largest prospective evaluation of audiologic status reported to date).

INTERVENTION(S): Demographics, clinical characteristics and history, audiometric evaluation, and Tinnitus Handicap Inventory (THI).

MAIN OUTCOME MEASURE(S): Type and degree of hearing loss, relationship to clinical course of SSCN, and expected results based on age and sex.

RESULTS

Sensorineural hearing loss (SNHL) is the most common symptom in SSCN (100%). Tinnitus (100%), imbalance (80%), and gait disorder (80%) were also frequently reported. Hearing loss is typically bilateral, asymmetric, progressive, sloping, and exceeds expected hearing loss related to age and sex. Hearing loss may be cochlear and/or retrocochlear in origin. Decreased word recognition is possible, and traditional amplification may offer limited benefit.

CONCLUSION

We observed significant audiometric findings in all participants. SSCN variably and pathologically targets the auditory system without regard for duration of disorder. A long asymptomatic phase and lack of predictive relationship between duration and severity of hearing loss makes suspicion of SSCN based solely on audiometric battery difficult; however, asymmetric hearing loss exceeding expectations, particularly with history of head trauma or previous neurosurgical procedure, should raise a red flag and trigger further medical evaluation including MRI. Diagnosis of SSCN may alter expectations for audiologic prognosis and is a critical component for comprehensive management of SSCN patients.