Comparison of the Speech Perception and Intelligibility after Cochlear Implantation between Hereditary and Non-hereditary Profound Prelingual Deaf Patients Admitted to Rasoul-e-Akram Hospital

When inner ear is disturbed, both hearing sensitivity and selective property decrease. Early rehabilitation for proper progression of speech and language appropriate to age is mandatory. Several studies were performed to compare factors that affect the results of cochlear implantations to select the best candidates on the basis of different criteria. This study was undertaken to compare speech perception and intelligibility between two groups of hereditary and non-hereditary deaf patients. Patients & In this descriptive-comparative study, prelingual patients(below the age of 7) who had profound deafness(unable to identify sounds with severity of>90 dB) and admitted to Rasoul-e-Akram Hospital(1992-2004) were assessed by census method. For determination of speech perception a standard CAP test as well as a standard 2-syllable words test were used and for determination of speech intelligibility a standard SIR test was used after 2 years of cochlear implantation. Relationship between parents and the existance of another deaf person in the family, with absence of definite cause for deafness, were considered as a hereditary deafness while other cases were considered as non-hereditary deafness. The mean age of patients was 71.47 months with SD=35.51. 42.5% of cases had hereditary and 57.5% of them had non-hereditary deafness. The mean perception scores of 2-syllable words were 45.78%(SD=34.73) and 46.28%(SD=33.85) in hereditary and non-hereditary deaf children respectively. Between two groups of hereditary and non-hereditary deaf children there was no significant difference in terms of frequency of different levels of speech perecption and mean percentage of two-syllable-word perception(the median of speech perception level in both hereditary and non-hereditary deaf children was the discrimination of some speech sounds without lip-reading). Also, the frequency of different levels of speech intelligibility(the median of speech intelligibility level) in both hereditary and non-hereditary deaf children was intelligible speech if someone concentrates. There was not any significant difference between speech perception or intelligibility and the mean perception scores of 2-syllable words in hereditary and non-hereditary deaf prelingual profound patients. Being hereditary or non-hereditary subject is not a helping factor to choose condidates for cochlear implantations.