Identifying the inner ear as the cause of dizziness in young children can be a challenge, but a few years ago an app was created that essentially replicates the subjective visual vertical (SVV) test. It mimics the more traditional SVV test in which a patient is asked to vertically position a glowing line while within a dark room. The ability to place the line accurately determines whether the dizziness arises from the brain or the inner ear, but having a dark and safe room available for such a test within a clinic can be pricey and cumbersome.
The Visual Vertical app by Clear Health Media, an Australian firm, utilizes an iPhone stuck to the bottom of a bucket to do essentially the same thing. It was recently trialed at Boston Children’s Hospital and demonstrated great results in detecting peripheral vestibular loss in peds between 7 and 18 years old.
From the study abstract in International Journal of Pediatric Otorhinolaryngology:
Methods: Thirty-nine patients between 7 and 18 years old (mean = 14.0 ± 2.70) underwent conventional SVV (conv-SVV) and smartphone-based SVV (ip-SVV) testing. Subjects included 6 with PVL (based on clinical history and other vestibular tests), 6 with benign paroxysmal positioning vertigo (BPPV), 11 with central causes of vertigo (CV), 8 with non-vestibular dizziness (NVD), and 8 controls.
Results: Mean ip-SVV score in the PVL group (2.77 ± 1.45) was significantly higher than in each of the other groups (BPPV = 0.89 ± 0.55; CV = 1.08 ± 0.68; NVD = 1.45 ± 1.19; Control = 1.08 ± 0.73; one-way analysis of variance, p = 0.008), and remained significant after adjusting for age and gender by multiple linear regression analysis. Receiver operating characteristic analysis predicted an optimal ip-SVV cut-off score of >2.13° with a sensitivity of 66.7%, specificity of 97.0%, positive predictive value (PPV) of 80%, and negative predictive value of 94.1% for detecting PVL. Sensitivity and PPV improved to 75% and 100%, respectively, when subjects tested >1 month after symptom onset (n = 24) were excluded.
Video describing how to use the app:
Study in International Journal of Pediatric Otorhinolaryngology: Peripheral vestibular loss detected in pediatric patients using a smartphone-based test of the subjective visual vertical…
iTunes link: Visual Vertical…