Assessing the Role of Nystagmus Slow Phase Velocity as a Prognostic Indicator in Idiopathic Sudden Sensorineural Hearing Loss: A Prospective Study.

Abstract

Introduction: Idiopathic sudden sensorineural hearing loss (ISSNHL) exhibits a diverse range of clinical presentations and treatment responses. Currently, there are no established variables that clinicians can utilize for the purposes of patient counseling when treating ISSNHL.

Materials and methods: This prospective study involved 35 patients diagnosed with ISSNHL who were treated with oral and intratympanic steroid injections. We measured the peak and average slow phase velocity (SPV) (°/sec) of nystagmus after caloric stimulation during the first session of intratympanic steroid injection (ITI), and four variables were evaluated: age, time elapsed before treatment (ET), gain, and pure tone average (PTA) posttreatment. An association between these variables was determined using Spearman's Rho statistical analysis, followed by regression modeling.

Results: We found a strong significant correlation between SPV and gain and PTA posttreatment (Spearman Rho 0.000). A significant correlation between SPV and ET was also detected (Spearman Rho 0.05). The linear regression analysis indicated that for every 1° increase in SPV, there is an expected increase of 0.27 dB in gain and a decrease of 0.18 dB in PTA posttreatment. Furthermore, an SPV of 17.7 (°/sec) demonstrated a strong correlation with Siegel grade 1 posttreatment (p 0.000).

Conclusions: The SPV (°/sec) of nystagmus during the first ITI may serve as a valuable tool for patient counseling in the management of ISSNHL, thereby encouraging the continuation or consideration of alternative treatment options. Further studies are warranted to validate these findings.