Cochlear implants improve speech perception in early bilateral SNHL

By Ingrid Grasmo, medwireNews Reporter

Cochlear implant surgery in children with an early diagnosis of bilateral sensorineural hearing loss (SNHL) results in significant progressive improvements in speech perception and intelligibility, suggest study findings.

The research, conducted in children living in Western Sicily, extends findings from other European studies and also shows that individual characteristics and family profile are not associated with speech perception improvements.

"Results from this study... could be generalized to other children who need cochlear implants and can be used to monitor the development of speech perception and intelligibility, as well as to establish appropriate parental expectations," say Francesco Martines (Universita degli Studi di Palermo, Italy) and co-authors.

The team assessed behavioral audiometry and speech recognition using validated measures in 28 infants with congenital or acquired bilateral SNHL who had undergone cochlear implant surgery in the first 2 years of life.

Children had an early diagnosis of SNHL (average 5.8 and 12.2 months for congenital and acquired hearing loss) and a relatively short time of deafness (average 6.8 months). None had derived previous benefit from hearing aids or shown signs of intellectual disability.

Follow up over 12-18 months revealed a significantly improved capacity to detect the presence of sounds compared with at baseline. Sounds within the spectrum of conversational speech were easily detected, with frequency recognition of 0.5, 1 and 2 KHz at 12 months and the additional 4 KHz at 18 months.

No family-related variable, including economic and educational status, and use of private speech therapy, predicted hearing ability at follow up.

The team notes that the Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) tests used in the study revealed speech performances equal to those reported for children of similar age with normal hearing (CAP median value of 3 and SIR category 3 in 46.4%).

"These results confirm previous demonstration of improved auditory speech perception," write the authors in the International Journal of Pediatric Otorhinolaryngology.

While the findings are encouraging, the researchers note that daily use of the cochlear implant would be required to derive a significant improvement in speech perception. Indeed, discontinuous use was observed among four of the five children who showed a lower progression in speech recognition.

Martines and colleagues warn that a larger study sample and a follow up of 3-5 years post implantation is needed to confirm the results.

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