NEW TEST SEEKS OUT COCHLEAR DEAD ZONES
LONDON–A new project funded by Deafness Research UK <www.deafnessresearch.org.uk> is seeking to improve understanding of why hearing aids don’t work for everyone as well as they should. The project is seeks ways to identify dead regions of the cochlea where amplification does not improve hearing and can even make it worse. Current hearing tests can often miss these dead regions.
Research led by Dr. Brian Moore, professor of auditory perception at the University of Cambridge, has led to the development of the Psychophysical Tuning Curves (PTC) test, which can measure the extent of these dead regions much more precisely than existing tests. The test can run on any personal computer, making it ready to use in the clinic immediately.
Vivienne Michael, chief executive of Deafness Research UK, said, “Thanks to the new PTC test, many more people who rely on hearing aids are going to benefit from enhanced performance and enhanced hearing ability.”
Moore said, “This research gives us access to more accurate information about individual patterns of hearing loss at different frequencies and about the extent of dead regions, in turn enabling better fitting of hearing aids. For example, if two people have the same audiogram, but one has dead regions, that person’s hearing aids will need to be programmed differently.”
Ross Roeser, PhD, editor in chief of the International Journal of Audiology, wrote in a recent editorial that the new test “represents a significant new opportunity for audiologists and hearing scientists to gain valuable knowledge of basic physiological processing of the auditory system.”
MANY HEARING-IMPAIRED NEWBORNS ESCAPE DETECTION
WASHINGTON, DC—Despite universal newborn hearing screening (UNHS) programs throughout the U.S., researchers report that the tests fail to identify nearly a third of those who later become pediatric cochlear implant recipients.
In their article in the March Archives of Otolaryngology-Head & Neck Surgery, Nancy Melinda Young, MD, of Children’s Memorial Hospital, Chicago, and co-authors write, “When UNHS programs were conceived, it was presumed that most hearing-impaired children, especially those without risk factors for progressive hearing loss, would fail the objective screening performed during the newborn period, thus making early diagnosis and intervention possible on a widespread basis.”
The scientists’ study of data for 391 children who received cochlear implants in Illinois from 1991 through 2008 found that 85% of those born after 2003 when universal screening became mandatory in the state were screened, as compared to 33% of those born before 2003. Of the 127 children born after the mandate, 65% had a known cause of or risk factor for hearing loss, and 25% of them passed hearing screenings.
The authors wrote, “Delayed onset of sensorineural hearing loss limits our ability to achieve early diagnosis and implantation of a significant number of deaf children.”
On the positive side, after the UNHS mandate took effect cochlear implant recipients were significantly younger when diagnosed with hearing loss and when implanted than children born prior to passage of the law.