[Diagnostics of latent vestibular dysfunction based on the characteristics of provocative nystagmus]

The objective of the present study was to develop a new method for the diagnostics of latent vestibular dysfunction and estimate its effectiveness based on the characteristics of spontaneous nystagmus, provocative nystagmus, and vestibuloocular optokinetic reflexes in servicemen operating moving systems. Moreover, the study was designed to assess the diagnostic and prognostic value of the new method. The study involved a total of 95 patients in whom the vestibular function was evaluated by clinical methods. The analysis included parameters of spontaneous nystagmus and provocative nystagmus, vestibuloocular reflex and optokinetic nystagmus in the patients of different study groups. It was demonstrated that 83.33% of the patients presenting with the minimal neurologic deficit syndrome show the positive response in the Valsalva maneuver. The medical history of peripheral vestibular syndrome and syndrome of vertebrogenic vestibular dysfunction is significantly more frequently associated with positive results of the sinocarotid test (p<0.05) than other syndromes. Mean reactivity coefficients of the vestibuloocular reflex are high in both groups and show no asymmetry. Analysis of the likelihood ratio for positive responses confirms the prognostic value of individual algorithms and of the entire scheme of diagnostic examination for the detection of latent vestibular dysfunction.