Objectives: To investigate the incidence of nystagmus in patients with sudden sensorineural hearing loss (SSNHL) without dizziness, and to evaluate the correlation of the presence of nystagmus with hearing recovery in those patients.
Study design: Retrospective study.
Setting: Tertiary referral academic medical center.
Patients: Thirty-eight patients with SSNHL who did not complained of dizziness were enrolled.
Main outcome measure: The presence of nystagmus was evaluated by recording eye movements, and if present, nystagmus was classified as direction-fixed or positional nystagmus. Vestibular function tests were performed, including caloric test.
Results: Of 33 idiopathic SSNHL patients without dizziness, nystagmus was observed in 22 patients (67%), of which 14 patients exhibited direction-fixed nystagmus, and 8 patients exhibited direction-changing nystagmus. Among the 14 patients with direction-fixed nystagmus, 9 displayed the paretic type, and 5 displayed the irritative type. Direction-changing nystagmus (n = 8) was defined as that in which the direction of nystagmus was changed in a supine head-roll test, and the geotropic type and apogeotropic type were observed in two and six patients, respectively. The mean initial pure tone threshold was 58.2 ± 28.1 dB and 57.3 ± 20.0 dB in SSNHL patients with and without nystagmus, respectively, which was not significantly different (p = 0.925). When hearing improvement was compared according to the presence of nystagmus, 39% (8 of 21) of patients with nystagmus were found to belong in the good prognosis group, and 72% (8 of 11) of patients without nystagmus were found to belong in the good prognosis group, which showed marginal statistical significance (p = 0.063).
Conclusion: Nystagmus was observed in two-thirds of idiopathic SSNHL patients without dizziness, and the pattern of nystagmus was either direction fixed or direction changing. Because hearing recovery was worse in patients with nystagmus than those without it, the diagnosis of nystagmus, even in SSNHL patients without dizziness, may be important in evaluating the hearing prognosis.