Cochlear implant corrects hearing but does not translate to actual perceived benefits

27 Apr 2022 bởiStephen Padilla
Cochlear implant corrects hearing but does not translate to actual perceived benefits

Cochlear implantation (CI) improves both audiologic and tinnitus outcome measures in patients with single-sided deafness (SSD), but the speech discrimination score (SDS) remains in nonserviceable range, while only a modest improvement is seen in quality-of-life (QoL) measures, reports a Singapore study.

“Our Asian study suggests that improved audiologic measures of CI in SSD may not translate to actual patient perceived benefits,” the researchers said. “Patients should be appropriately counseled to ensure their expectations of going from monoaural to binaural hearing are not overstated.”

The study included eight patients with idiopathic sudden sensorineural hearing loss of less than 5-year duration. The researchers performed pure tone average (PTA), SDS, hearing-in-noise test (HINT), tinnitus handicap inventory (THI), QoL speech spatial qualities (SSQ) scale tests before and 1 year after CI. They also determined the long-term usage of CI postoperatively.

The median PTA of the deaf ear was 96 and 30 dBHL before and after CI, respectively (p=0.0156). From a median of 0 percent, SDS improved to 33 percent (p=0.0360). The median signal-to-noise ratio (SNR), particularly of the S0Nbetter setting of HINT, also improved from 6.4 to 0.9 dB (p=0.1094). [Proc Singap Healthc 2022;doi:10.1177/20101058221083393]

“Our results show significant improvement of PTA scores in the implanted ear, with the postoperative median achieving near-normal 30 dB levels,” the researchers said. “SDS scores showed statistically significant improvement, [but] the median score of 33 percent remains in the level of nonserviceable hearing.”

Two patients, however, had worsening of tinnitus despite median THI improving from 24 to 4 (p=0.1563). In addition, SSQ scores in all subscales improved modestly but did not reach statistical significance. Of note, majority of the patients (five out of eight, 62 percent) discontinued the use of their implant 4 years after surgery.

A 2019 study with 60 SSD patients who received CI reported only four participants not using their implants throughout the study, but the actual nonusage rate could have been higher due to a lost to follow-up rate of 42 percent at 2 years. However, the study concluded that binaural benefit and sound localization improved gradually with time. [Laryngoscope 2020;130:1805-1811]

Another Asian study performed in Japan also showed fluctuations in hearing results among five SSD patients with CI potentially due to time needed for binaural integration. [Acta Otolaryngol 2016;136:460-464]

“In comparison, our study provided audiology and subjective tests up to 1 year,” the researchers said. “We speculate if our test results could have continued to improve over time beyond the duration of this study.”

Aural rehab

Children with CI demonstrated improved hearing outcomes following aural rehabilitation, while both children and adults showed improved speech outcomes. [Cochlear Implants Int 2018;19:38-45; Dan Med J 2019;66; Otol Neurotol 2019;40:e975-e83]

Moreover, auditory rehabilitation resulted in better outcomes among adult CI users with SSD. [Cochlear Implants Int 2019;20:231-236]

“We postulated that more auditory skills training, with goals carried over to the home setting, will improve the hearing outcomes,” the researchers said. “Two Listening and Spoken Language Specialists Certified Auditory Verbal Therapists provided the necessary rehabilitation sessions for this study.”