[Early signs of occupational ototoxicity caused by inhalation of benzene derivative industrial solvents]. / Studio dei segni precoci di ototossicità professionale da inalazione di solventi industriali derivati dal benzene.

People exposed to industrial solvents may suffer from disturbances of different psycho-physiological and vestibulo-oculomotor function. Therefore an investigation was performed testing vestibular and oculomotor reactions in workers exposed to solvents. It also seemed to be of interest to study if the auditory pathways were affected in these workers. 53 men aged 27-54 (Md = 37.7) were studied. They had been exposed to aromatic solvents in their work as colour mixers, painters, printers and petrol truck drives. Time of working was between 4-25 (Md = 15.2) years. At the time of this investigation none of the men had been exposed to solvents for at least the last four years. The clinical investigation included cerebellar tests and a general ENT investigation. Electronystagmography was performed and comprised the following functions: 1) spontaneous and caloric vestibular tests; 2) a sinusoidal swing test in darkness, the patient sitting in a rotatory chair; 3) visual suppression test; 4) a saccade test; a slow pursuit eye movement test. In addition all the patients were subjected to an audiological test battery including pure tone threshold, conventional vocal audiometry, speech discrimination used interrupted speech 10 interruptions per second, acoustic reflex thresholds and reflex decay. The clinical investigation showed in 19 patients balance problems in the balance test. The sinusoidal test was normal in all cases. The caloric test showed 8 cases of asymmetry in vestibular reactions. 10 of the patients had pathological spontaneous nystagmus. 17 of the patients had a pathologically decreased ability for visual suppression. The saccades were abnormal in 25 patients. The patients who were subjected to audiological testing all had pure tone thresholds and conventional vocal thresholds as expected with regard to age. 31 patients showed decreased discrimination scores at the interrupted speech. The acoustic reflex thresholds were normal and there was not pathological reflex decay. Results show the prevalently pathologic concern for C.N.S. Authors, last, give prominence to the significant relationship between the exposure time to solvents' vapour and changing of several parameters, connection conditioned by constitution and life habits in predisposing workers to a greater susceptibility at damages caused by organic solvents.