Is there a relationship between the acoustic occlusion effect and the sensation of occlusion?

The objective of the present investigation was to examine the relationship between the acoustic occlusion effect and the subjective occlusion sensation when using ear moulds. The material comprises 45 subjects (19M and 26F, at a median age of 76 years, range 38-88 years) subgrouped according to the classification of their hearing disorder into two group: N = 22 subjects with conductive hearing loss (1); N = 21 subjects with sensorineural hearing loss (2). The side effects caused by an ear mould were evaluated at an interview, based on a structured questionnaire, two months after the hearing aid fitting. The comparative investigation showed that when the outer ear canal was occluded with an ear mould there were no significant differences between the two groups of subjects in the frequency of sensation of occlusion, in the sound quality of environmental sound or own voice, in hearing problems when chewing, or in ventilation problems. Neither were significant differences in the magnitude of the acoustic occlusion effect present between those answering yes and those answering yes and those answering no to a change in the sound quality of own voice in the group with sensorineural hearing loss. Although the number of subjects is limited, it is concluded that no relationship exists between the acoustic occlusion effect and the perceived sound quality, thus leaving no physical basis for the claim that this side effect is caused by an ear mould.