Visual function and symptom provocation in children and young adults with vestibular disorders: A prospective controlled study

PURPOSE: To understand if visual function tests with moving stimuli were harder to process and caused more symptom provocation in persistent postural perceptual dizziness (PPPD) patients compared with those with other vestibular diagnoses or without any vestibular symptoms. METHODS: 61 patients aged 8-23 years participated in a prospective study with three groups: PPPD (n = 21); at least one vestibular disorder without PPPD (n = 20); control-without vestibular or vision symptoms (n = 20). Subjects underwent visual function tests with moving stimuli: near point of convergence (NPC), amplitude of accommodation (AA), radial (r), and translational (t) motion coherence (MC). Somatic (headache, dizziness, nausea, fogginess) and eye symptom provocation (eyestrain, eye discomfort, pressure around the eyes) were assessed at baseline and after each visual function test using a Likert scale. Chi-squared tests compared rates of failure and Kruskal-Wallis tests compared measures between groups. Symptom provocation between groups and baseline versus postvisual function tests were compared using one-way ANCOVA and two-way repeated measures ANOVA, respectively. RESULTS: Patients with PPPD (median 10.0 Diopters (D) IQR [8.8-11.6]) had the lowest mean AA measures relative to those with other vestibular disorders (median 13.3D IQR [10.4-15.8], p = 0.01) and controls (median 13.5D IQR [12.2-17.0], p < 0.001). Between groups, somatic symptom provocation of PPPD patients was significantly higher than those with other vestibular disorders and control groups at baseline and following each visual function test (p < 0.05). Only patients with PPPD demonstrated consistently elevated eye symptom provocation following each visual function test (NPC mean difference [MD] = 4.1, 95% CI 2.4-5.8, p < 0.001; AA MD = 3.5, 95% CI 1.6-5.3, p < 0.001; rMC MD = 5.0, 95% CI 3.2-6.8, p < 0.001; tMC MD = 5.3, 95% CI 3.3-7.3, p < 0.001). CONCLUSIONS: Patients with PPPD had significantly lower AA and considerably elevated eye symptom provocation at baseline and after visual function tests compared to those with other vestibular disorders and controls. These findings may improve understanding of the pathophysiology of PPPD and its effective diagnosis and treatment.