Proposal on the Diagnostic Criteria of Definite Isolated Otolith Dysfunction

BACKGROUND AND OBJECTIVES: Dizzy patients with abnormal otolith function tests, despite a normal caloric response, are defined as having specific (isolated) otolith organ dysfunction. This study was performed to compare the differences in clinical presentation between isolated otolith dysfunction (iOD) patients with lab- and Sx-based iOD group and lab-based iOD symptoms. SUBJECTS AND METHODS: The medical records of 23 iOD patients with normal caloric response but abnormal cervical vestibular evoked myogenic potential (VEMP), ocular VEMP, or subjective visual vertical were reviewed. Non-spinning vertigo was considered as otolith-related symptoms. The patients’ age, onset of dizziness, Numeric Rating Scale on the severity of dizziness, and concomitant vestibular disorders were analyzed. RESULTS: Patients in the lab-based iOD group were significantly older than those in the lab- and Sx-based iOD group. Known vestibular disorders were significantly more common in the lab-based iOD group (83.3%) compared to the lab- and Sx-based iOD group (18.2%). Despite the normal caloric response, catch-up saccade was found in the video head impulse test in more than half (54.5%) of the lab-based iOD group patients. There was no catch-up saccade in the lab- and Sx-based iOD group. There were no significant differences in gender ratio, frequency of dizziness attacks, and duration of illness. CONCLUSIONS: We propose new definitions of definite iOD (lab- and Sx-based iOD) and probable iOD (lab- or Sx-based iOD). These new definitions may help researchers to identify patients who are more likely to have true iOD, and facilitate comparisons of results between different studies.

The Effects of the Vestibular Rehabilitation on the Benign Paroxysmal Positional Vertigo Recurrence Rate in Patients with Otolith Dysfunction

BACKGROUND AND OBJECTIVES: Although repositioning maneuvers have shown remarkable success rate in treatments of benign paroxysmal positional vertigo (BPPV), the high recurrence rate of BPPV has been an important issue. The aims of present study were to examine the effects of otolith dysfunction on BPPV recurrence rate and to describe the effect of vestibular rehabilitation exercises on BPPV recurrence in BPPV patients with concomitant otolith dysfunction. SUBJECTS AND METHODS: Forty-five BPPV patients included in this study (three groups). Patients in group 1 had no otolith dysfunction and patients in groups 2 and 3 had concomitant otolith dysfunction. Otolith dysfunction was determined with ocular/cervical vestibular evoked myogenic potential (oVEMP and cVEMP) abnormalities. Epley’s maneuver was performed for the patients in all groups but patients in group 3 also received a 2-month vestibular rehabilitation program (habituation and otolith exercises). RESULTS: This study showed that BPPV recurrent rate was significantly higher in patients with otolith dysfunction in comparison to the group 1 (p < 0.05). Vestibular rehabilitation resulted in BPPV recurrence rate reduction. Utricular dysfunction showed significant correlation with BPPV recurrence rate. CONCLUSIONS: Otolith dysfunction can increase BPPV recurrence rate. Utricular dysfunction in comparison to saccular dysfunction leads to more BPPV recurrence rate. Vestibular rehabilitation program including habituation and otolith exercises may reduce the chance of BPPV recurrence.