Clinical experience with remote masking.

Remote masking (RM) consists of a rise of the threshold for low-pitched tones when the ear is exposed to a high-frequency noise band delivered with high intensity. This phenomenon has been attributed to mechanical non-linear distortion of the cochlear partition, as an effect of the envelope of a non-uniform signal. The authors studied RM in patients suffering from unilateral Menière's disorder, acoustic neuromata, other sensorineural lesions and presbyacusis. The behaviour of RM in the different experimental groups shows that the RM value is normal in acoustic neuromata; it is variable and not related to the severity of the hearing loss in sensorineural losses, and it is reduced in the affected ear in patients suffering from Menière's disorder. Finally, RM is reduced as a function of ageing, progressively and symmetrically in both ears in presbyacusic subjects. The results of the research seem to confirm the hypothesis that RM may be due to mechanical effects in the inner ear and suggest the possibility of using RM as a test of cochlear partition rigidity.