Hard to Predict Which Adults Will Benefit From Cochlear Implants

By Lisa Rapaport

June 02, 2020

(Reuters Health) - Many adults with hearing loss that isn't improved with hearing aids can benefit from cochlear implants, but a new meta-analysis suggests patient characteristics are poor predictors of outcome.

Researchers pooled data on 1,095 patients from 13 studies of speech recognition in adults who received cochlear implants. Mean age at implantation ranged from 51.2 to 63.7 years, and mean duration of hearing loss ranged from 9.5 to 31.8 years.

Correlations were weak, negligible, or absent between word and sentence recognition after receipt of cochlear implants and several individual patient characteristics, including age at implantation, duration of hearing loss, pre-implant earphone pure-tone average, and pre-implant word recognition, the study team reports in JAMA Otolaryngology-Head & Neck Surgery.

The study did find a weak negative correlation between patients' age when they received cochlear implants and sentence recognition in quiet (r = 0.31). All of the other correlations, while statistically significant, were absent to negligible (r = -0.02 to 0.27).

"There are several potential reasons why we did not find any strong associations," said coauthor Dr. Ted McRackan, medical director of the Cochlear Implant Center at the Medical University of South Carolina in Charleston.

One possibility is that the factors researchers examined don't strongly influence the ability to understand speech, Dr. McRackan said by email.

"Second, in our meta-analysis, we could only include patient factors that have been examined and reported in published studies with patients with cochlear implants," he added. "Other factors such as cognitive ability, education level, and cochlear nerve health may have a significant impact."

The researchers had intended to perform a metaregression of patient-specific variables and control for cofounders, but only three of the studies had the necessary data.

In addition, studies that included the correlation values didn't include data from audiology exams performed before and after receipt of cochlear implants. This made only univariate analysis possible.

"The fact the we observe relatively poor correlation between speech recognition scores using a cochlear implant and common preoperative patient factors just tells us that the patient factors are not good biomarkers of the individual's hearing system status," said Dr. Matthew Shew, of the Otolaryngology Head & Neck Surgery department at Washington University School of Medicine in St. Louis, Missouri, who coauthored a commentary accompanying the study.

"It stands to reason that the status of the entire auditory pathway, from the cochlea, auditory nerve, and the brain connections should play a major role in determining a patient's speech recognition ability with a cochlear implant," Dr. Shew said by email. "Yet we have not clearly identified the patient's factors that strongly predict this status."

SOURCE: https://bit.ly/3drr05S and https://bit.ly/3etgtrd JAMA Otolaryngology-Head & Neck Surgery, online May 14, 2020.