Capturing acute vertigo A vestibular event monitor

Objective To facilitate the diagnosis of vestibular disorders by patient-initiated capture of ictal nystagmus. Methods Adults from an Australian neurology outpatient clinic reporting recurrent vertigo were recruited prospectively and taught to self-record spontaneous and positional nystagmus at home while symptomatic, using miniature video-oculography goggles. Consenting patients with ictal videorecordings and a final unblinded clinical diagnosis of Meniere disease (MD), vestibular migraine (VM), or benign paroxysmal positional vertigo (BPPV) were included. Results Ictal eye videos of 117 patients were analyzed. Of 43 patients with MD, 40 showed high-velocity spontaneous horizontal nystagmus (median slow-phase velocity [SPV] 39.7 degrees/s; 21 showed horizontal nystagmus reversing direction within 12 hours [24 on separate days]). In 44 of 67 patients with VM, spontaneous horizontal (n = 28, 4.9 degrees/s), upbeating (n = 6, 15.5 degrees/s), or downbeating nystagmus (n = 10, 5.1 degrees/s) was observed; 16 showed positional nystagmus only, and 7 had no nystagmus. Spontaneous horizontal nystagmus with SPV > 12.05 degrees/s had a sensitivity and specificity of 95.3% and 82.1% for MD (95% confidence interval [CI] 0.84-0.99, 0.71-0.90). Nystagmus direction change within 12 hours was highly specific (95.7%) for MD (95% CI 0.85-0.99). Spontaneous vertical nystagmus was highly specific (93.0%) for VM (95% CI 0.81-0.99). In the 7 patients with BPPV, spontaneous nystagmus was absent or < 3 degrees/s. Lying affected-ear down, patients with BPPV demonstrated paroxysmal positional nystagmus. Median time for peak SPV to halve (T50) was 19.0 seconds. Patients with VM and patients with MD demonstrated persistent positional nystagmus (median T50; 93.1 seconds, 213.2 seconds). T50s < 47.3 seconds had a sensitivity and specificity of 100% and 77.8% for BPPV (95% CI 0.54-1.00, 0.64-0.88). Conclusion Patient-initiated vestibular event monitoring is feasible and could facilitate rapid and accurate diagnosis of episodic vestibular disorders.