A State-of-the-Art Method for Preserving Residual Hearing During Cochlear Implant Surgery.

The developments in surgical techniques and cochlear implant (CI) electrode design have expanded the indications for CI treatment. Currently, patients with high-frequency hearing loss may benefit from CIs when low-frequency residual hearing can be preserved, as this enables combined electric-acoustic stimulation (EAS). The possible benefits of EAS include, for example, improved sound quality, music perception, and speech intelligibility in noise. The risks of inner ear trauma and a deterioration or even complete loss of residual hearing vary according to the surgical technique and the type of electrode array used. Short, lateral-wall electrodes with shallower angular insertion depths have demonstrated higher rates of hearing preservation than longer electrodes. The very slow insertion of the electrode array through the round window of the cochlea contributes to insertion atraumaticity and, thus, may lead to favorable hearing preservation results. However, residual hearing can be lost even after an atraumatic insertion. Electrocochleography (ECochG) can be used to monitor inner ear hair cell function during the insertion of the electrode. Several investigators have demonstrated that the ECochG responses during surgery may predict postoperative hearing preservation results. In a recent study, we correlated the patients' subjective hearing perception with simultaneously recorded intracochlear ECochG responses during the insertion. This is the first report evaluating the association between intraoperative ECochG responses and hearing perception in a subject undergoing cochlear implantation under local anesthesia without sedation. The combination of intraoperative ECochG responses with the patient's real-time feedback to sound stimuli has excellent sensitivity for the intraoperative monitoring of cochlear function. This paper presents a state-of-the-art method for the preservation of residual hearing during CI surgery. We describe this treatment procedure with the special consideration of performing the surgery under local anesthesia, which makes it feasible for monitoring the patient's hearing during the insertion of the electrode array.

The Effectiveness of Unilateral Cochlear Implantation on Performance-Based and Patient-Reported Outcome Measures in Finnish Recipients.

Understanding speech is essential for adequate social interaction, and its functioning affects health, wellbeing, and quality of life (QoL). Untreated hearing loss (HL) is associated with reduced social activity, depression and cognitive decline. Severe and profound HL is routinely rehabilitated with cochlear implantation. The success of treatment is mostly assessed by performance-based outcome measures such as speech perception. The ultimate goal of cochlear implantation, however, is to improve the patient's QoL. Therefore, patient-reported outcomes measures (PROMs) would be clinically valuable as they assess subjective benefits and overall effectiveness of treatment. The aim of this study was to assess the patient-reported benefits of unilateral cochlear implantation in an unselected Finnish patient cohort of patients with bilateral HL. The study design was a prospective evaluation of 118 patients. The patient cohort was longitudinally followed up with repeated within-subject measurements preoperatively and at 6 and 12 months postoperatively. The main outcome measures were one performance-based speech-in-noise (SiN) test (Finnish Matrix Sentence Test), and two PROMs [Finnish versions of the Speech, Spatial, Qualities of Hearing questionnaire (SSQ) and the Nijmegen Cochlear Implant Questionnaire (NCIQ)]. The results showed significant average improvements in SiN scores, from +0.8 dB signal-to-noise ratio (SNR) preoperatively to -3.7 and -3.8 dB SNR at 6 and12 month follow-up, respectively. Significant improvements were also found for SSQ and NCIQ scores in all subdomains from the preoperative state to 6 and 12 months after first fitting. No clinically significant improvements were observed in any of the outcome measures between 6 and 12 months. Preoperatively, poor SiN scores were associated with low scoring in several subdomains of the SSQ and NCIQ. Poor preoperative SiN scores and low PROMs scoring were significantly associated with larger postoperative improvements. No significant association was found between SiN scores and PROMs postoperatively. This study demonstrates significant benefits of cochlear implantation in the performance-based and patient-reported outcomes in an unselected patient sample. The lack of association between performance and PROMs scores postoperatively suggests that both capture unique aspects of benefit, highlighting the need to clinically implement PROMs in addition to performance-based measures for a more holistic assessment of treatment benefit.

A Comparison of ECochG With the Subjective Sound Perception During Cochlear Implantation Under Local Anesthesia-A Case Series Study.

OBJECTIVE: Intraoperative electrocochleography (ECochG) has been proposed for cochlear monitoring to minimize trauma during the insertion of the electrode of a cochlear implant (CI). CI surgery is normally performed under general anesthesia, which is why intraoperative ECochG measurements have never been validated against the patient's subjective sound perception. The main objectives of this study were to investigate the feasibility of cochlear monitoring based on the patients hearing and to validate it against intraoperative ECochG measurements during CI surgery under local anesthesia. STUDY DESIGN: Prospective case series study. SETTING: Tertiary referral center. PATIENTS: Patients eligible for cochlear implantation with residual hearing (pure-tone threshold averages [PTA] 2501000 Hz ≤ 75 dB HL). Additionally, patients should be able to hear ECochG stimuli at 250, 500, or 1000 Hz at less than or equal to 100 dB (HL). INTERVENTIONS: Cochlear implantation under local anesthesia without conscious sedation. Intraoperative ECochG monitoring. MAIN OUTCOME MEASURES: The development of ECochG amplitudes and the patients' subjective perception to the sound stimuli. RESULTS: In all patients, monitoring based on their subjective sound perception was feasible, whereas, reliable ECochG responses could be measured in seven patients. Sixty percent of the registered declines in ECochG amplitude were associated with a concomitant attenuation of the subjectively perceived sound. CONCLUSIONS: The developments in the ECochG responses matched well with the changes of the sound stimulus perceived by the patients, which supports the applicability of ECochG for preventing insertion trauma. Monitoring of the patients subjective hearing appears to be more reliable than ECochG but requires surgery under local anesthesia without conscious sedation.