Otovestibular findings in workers affected by industrial poisons[Rilievi otovestibolari in operai intossicati da tossici industriali]

Abstract This research was undertaken to investigate vestibular function in a group of workmen exposed to inhalatory poisons affecting the central nervous system. It was thought useful to bring an instrumental objectivity to a complex subjective symptomatology such as vertigo, headache, asthenia and nausea. The examination of vestibular function was done with the Veits test. Acute sulfur dioxide poisoning provoked a reduction of reflexes in 70% of cases. Slow poisoning provoked an analogous syndrome in 42% of cases. Nystagmus duration remained within limits, though decreased. The report points out that this poison acts on a vestibular, nuclear and reticular level. Tetraethyl lead provoked a clear reduction of movements in 65% of cases and in rare cases a reduction of duration. It also acts on a vestibular and reticular level. Hydrocyanic acid determined a reduction either of movements or of nystagmus duration in 59% of cases. Thus, this poison acts most probably not only on vestibular, reticular and nuclear level but also on vestibular peripheral receptors. Carbon monoxide provoked in 60% of examined cases a reduction of movements without a parallel reduction of nystagmus duration. This poison also acts on a vestibular, nuclear and reticular level. In 33% of cases carbon monoxide determined a perceptive hypoacusis prevalent for middle and acute tones with an audiometric tonal descent curve of more or less marked degree. With carbon disulfide in 41% of cases a vestibular, nuclear and reticular level is affected. In 11% of cases a clear vestibular hyperreflex was found that was bound not to the action of the same poison but to cerebral vasculopathy secondary to the poison action. Toluene did not alter vestibular function significantly. Trichloroethylene provoked a clear increase of vestibular reflectivity in 40% of cases. Such poison action on the vestibular central system is due to interference with the central nervous system metabolites. Exposure to paints induced a polymorphic vestibular syndrome; i.e., in 20% of cases a vestibular hyporeflectivity was found, while in 36% a hyperreflectivity was found. It was thought that otofunctional tests carried out with the Veits technique can be of help in measuring instrumentally the complex subjective symptomatology that is present in workmen exposed to the action of industrial poisons, as it is simple and quick and it shows up early alterations in the central nervous system.