Vestibular Dysfunction in Patients With Superficial Siderosis of the Central Nervous System.

OBJECTIVE: To describe the vestibular function in patients with superficial siderosis of the central nervous system (SSCN). STUDY DESIGN: Retrospective analysis. SETTING: Tertiary referral center. PATIENTS: Ten consecutive patients with SSCN. This study is the largest case series of SSCN in which detailed neuro-otological findings, including electronystagmography recording, video head impulse test (vHIT), and posturography, were described. INTERVENTIONS: Audiological and neuro-otological examinations, including pure-tone audiometry, distortion product otoacoustic emissions, speech audiometry, auditory brainstem responses, electronystagmography recording, vHIT, and posturography. MAIN OUTCOME MEASURES: Pure-tone average, DP level, maximum speech discrimination score, interpeak latency between auditory brainstem responses waves I and V, eye tracking test, examination of optokinetic nystagmus, caloric response, visual suppression, vestibulo-ocular reflex gains, total center of pressure path length, and Romberg's ratio. RESULTS: Audiological examinations suggested that the sensorineural hearing loss was of a cochlear etiology in 3 ears, a retrocochlear etiology in 11 ears, and a combined cochlear and retrocochlear etiology in 6 ears. Neuro-otological examinations revealed that eight out of nine patients had cerebellar disorders, while all patients also had peripheral vestibular dysfunction. CONCLUSION: In addition to cerebellar disorders, SSCN patients suffer from severe peripheral vestibular dysfunction, which can exacerbate the patient's imbalance. When otolaryngologists encounter patients with distinctly progressive sensorineural hearing loss and imbalance, they should include SSCN in the differential diagnosis and perform neuro-otological examinations, including an electronystagmography recording and vHIT and brain magnetic resonance imaging.

Brain activity in patients with unilateral sensorineural hearing loss during auditory perception in noisy environments.

Patients with unilateral sensorineural hearing loss (UHL) often complain of hearing difficulties in noisy environments. To clarify this, we compared brain activation in patients with UHL with that of healthy participants during speech perception in a noisy environment, using functional magnetic resonance imaging (fMRI). A pure tone of 1 kHz, or 14 monosyllabic speech sounds at 65‒70 dB accompanied by MRI scan noise at 75 dB, were presented to both ears for 1 second each and participants were instructed to press a button when they could hear the pure tone or speech sound. Based on the activation areas of healthy participants, the primary auditory cortex, the anterior auditory association areas, and the posterior auditory association areas were set as regions of interest (ROI). In each of these regions, we compared brain activity between healthy participants and patients with UHL. The results revealed that patients with right-side UHL showed different brain activity in the right posterior auditory area during perception of pure tones versus monosyllables. Clinically, left-side and right-side UHL are not presently differentiated and are similarly diagnosed and treated; however, the results of this study suggest that a lateralityspecific treatment should be chosen.