THURSDAY, Jan. 18 (HealthDay News) -- Outcomes are similar for both younger and older children who receive surgically implanted hearing aids (cochlear implants), Canadian researchers report.

Researchers at the Hospital for Sick Children in Toronto compared outcomes for 20 children aged 5 years or younger (average age was just over 3 years old) and 20 older children (averaging 7 to 8 years old) who received bone-anchored hearing aids over a 10-year period.

These devices are attached to the skull's temporal bone and treat hearing loss by directly stimulating the cochlea and conducting sound through the bone. Medical literature suggests the optimal age for implanting these hearing aids is 2 to 4 years, according to background information in the study.

Among the children in this study, the hearing devices were implanted using either a one- or two-stage procedure, depending on the thickness of the child's bone. In the two-stage procedure, the hearing aid's titanium fixture is implanted first, and the rest of the device is installed later.

All of the younger children and 18 of the older children in this study had the two-stage procedure. The length of time between the first and second procedure was 4.4 months in the older children and 7.7 months in the younger children. Four of the older children and two of the younger children experienced traumatic fixture loss -- the hearing aid components became loose or detached from the skull, and the children had to have surgery to repair the problem.

Three of the younger children also had skin site revision -- additional surgery that was needed due to poor hygiene or inadequate care at the surg ical site. All of the children still wear their bone-anchored hearing aids, and all have improved hearing.

"In conclusion, two-stage bone-anchored hearing aid implantation yields surgical success in younger children that is comparable in audiologic outcomes and traumatic device failures and/or revisions with that achieved in older children when there is an appropriate (i.e. lengthened) delay between surgical stages to allow for osseointegration (fusion to the bone)," the study authors wrote.

"Early implantation of bone anchored hearing aids allows the younger children who receive them to benefit from earlier speech and language habilitation," they added.

The findings were published in the January issue of the Archives of Otolaryngology-Head & Neck Surgery.

More information

The U.S. National Institute on Deafness and Other Communication Disorders has more about cochlear implants.