This PhD project is conducted within the discipline of audiology. The investigation methods are quantitative and cross-sectional, and the data are recorded outcomes of speech perception tests.
Typical consonant and vowel confusions in well-performing, pre- and postlingually deaf children and adults with cochlear implants (CIs) were investigated and compared to reference groups of normal-hearing children and adults. Consonants and vowels were presented in the context of mono- and bisyllabic nonsense words in a speech perception test.
The mainly prelingually deaf children with CIs obtained higher scores than the mainly postlingually deaf adult CI users. For both groups, consonants were mostly confused with other consonants with the same voicing and manner. Voiced consonants were less well perceived than unvoiced consonants, and there was a devoicing bias for the stops. A high confusion rate of nasals with other nasals was revealed, and [y:] was perceived as [i:] twice as often as [y:] was repeated correctly. The findings indicate that there still are limitations in today’s CI technology regarding the transmission of low-frequency sounds.
The study results will be useful for the development of new CI technology, and may also be beneficial for CI programming and for planning of auditory training and speech therapy for the implantees.
The work on this dissertation was conducted at the University of Oslo, Department of Special needs education. The data was collected at Oslo university hospital, ENT Department.