Despite successful preservation of low-frequency hearing in patients undergoing cochlear implantation (CI) with shorter electrode lengths, there is still controversy regarding which electrodes ...maximize hearing preservation (HP). The thin straight electrode array (TSEA) has been suggested as a full cochlear coverage option for HP. However, very little is known regarding its HP potential.
A retrospective review was performed at two tertiary academic medical centers, reviewing the electronic records for 52 patients (mean, 58.2 yr; range, 11-85 yr) implanted with the Cochlear Nucleus CI422 Slim Straight (Centennial, CO, USA) electrode array, referred to herein as the thin straight electrode array or TSEA. All patients had a preoperative low-frequency pure-tone average (LFPTA) of 85 dB HL or less. Hearing thresholds were measured at initial activation (t1) and 6 months after activation (t2). HP was assessed by evaluating functional HP using a cutoff level of 85 dB HL PTA.
At t1, 54% of the subjects had functional hearing; 33% of these subjects had an LFPTA between 71 and 85 dB HL, and 17% had an LFPTA between 56 and 70 dB HL. At t2, 47% of the patients had functional hearing, with 31% having an LFPTA between 71 and 85 dB HL.
Preliminary research suggests that the TSEA has the potential to preserve functional hearing in 54% of patients at t1. However, 22% (n = 6) of the patients who had functional hearing at t1 (n = 28) lost their hearing between t1 and t2. Further studies are needed to evaluate factors that influence HP with the TSEA electrode and determine the speech perception benefits using electric and acoustic hearing over electric alone.
To determine the safety and effectiveness of the middle cranial fossa (MCF) approach for spontaneous cerebrospinal fluid leak (sCSF-L) repair in class III obese patients. To also assess the need for ...prophylactic lumbar drain (LD) placement in this patient population.
Retrospective cohort study.
Tertiary Academic Center.
All patients older than 18 years undergoing sCSF-L repair with an MCF approach.
An MCF craniotomy for sCSF-L repair.
Rate of complications and postoperative leaks.
There were no perioperative complications in 78.9% (56/71) of cases. The surgical complication rate was 12.5% (2/16), 10% (2/20), and 22.2% (6/27) in class I, class II, and class III obese patients. There was no statistically significant difference in complications among these three groups. The most common postoperative complication was a persistent CSF leak in the acute postoperative period with an overall rate of 9.9% (7/71) with six of the seven patients requiring postoperative LD placement. The percentage of postoperative CSF leaks in nonobese, class I, class II, and class III patients were 25% (2/8), 12.5% (2/16), 0% (0/20), and 11.1% (3/27), respectively. There was no statistically significant difference in the rate of postoperative CSF leaks among the four groups (chi-square, p = 0.48). In all cases, the acute postoperative CSF leaks resolved in the long term and did not require further surgical repair.
We determine that MCF craniotomy repair for sCSF-Ls is safe in patients with class III obesity, and the incidence of postoperative CSF leaks did not vary among other obesity classes. We also find that prophylactic placement of LDs is not routinely needed in this population.
Understanding genetic causes of hearing loss can determine the pattern and course of a patient's hearing loss and may also predict outcomes after cochlear implantation. Our goal in this study was to ...evaluate genetic causes of hearing loss in a large cohort of adults and children with cochlear implants. We performed comprehensive genetic testing on all patients undergoing cochlear implantation. Of the 459 patients included in the study, 128 (28%) had positive genetic testing. In total, 44 genes were identified as causative. The top 5 genes implicated were
(20, 16%),
(13, 10%),
(10, 8%),
(9, 7%), and
(7, 5%). Pediatric patients had a higher diagnostic rate. This study lays the groundwork for future studies evaluating the relationship between genetic variation and cochlear implant performance.
This study examined the growth of expressive language skills in children who received cochlear implants (CIs) in infancy. Repeated language measures were gathered from 29 children who received CIs ...between 10 and 40 months of age. Both cross-sectional and growth curve analyses were used to assess the relationship between expressive language outcomes and CI experience. A beneficial effect of earlier implantation on expressive language growth was found. Growth curve analysis showed that growth was more rapid in children implanted as infants than those implanted as toddlers. Age at initial stimulation accounted for 14.6% of the variance of the individual differences in expressive language growth rates. (Contains 6 tables and 3 figures.)
To determine the efficacy and morbidity of repairing spontaneous cerebrospinal fluid (CSF) leaks with the middle cranial fossa (MCF) approach without the use of a lumbar drain (LD), as perioperative ...use of LD remains controversial.
Retrospective review from 2003 to 2015.
University of Iowa Hospitals and Clinics and Indiana University Health Center.
Those with a confirmed lateral skull base spontaneous CSF leaks and/or encephaloceles.
MCF approach for repair of spontaneous CSF leak and/or encephalocele without the use of lumbar drain. Assessment of patient age, sex, body mass index (BMI), and medical comorbidities.
Spontaneous CSF leak patient characteristics (age, sex, BMI, obstructive sleep apnea) were collected. Length of stay (LOS), hospital costs, postoperative complications, CSF leak rate, and need for LD were calculated.
Sixty-five operative MCF repairs were performed for spontaneous CSF leaks on 60 patients (five had bilateral CSF leaks). CSF diversion with LD was used in 15 of 60 patients, mostly before 2010. After 2010, only three of 44 patients (6.7%) had postoperative otorrhea requiring LD. The use of LD resulted in significantly longer LOS (3.6 ± 1.6 versus 8.7 ± 2.9 d) and hospital costs ($29,621). There were no postoperative complications in 77% (50 of 65) of cases. Three cases required return to the operating room for complications including frontal subdural hematoma (1), subdural CSF collection (1), and tension pneumocephalus (1). No patients experienced long-term neurologic sequelae or long-term CSF leak recurrence with an average length of follow-up of 19.5 months (range 3-137 mo). The average patient BMI was 37.5 ± 8.6 kg/m. The average age was 57.5 ± 11.4 years and 68% were female. Obstructive sleep apnea was present in 43.3% (26 of 60) of patients.
The morbidity of the MCF craniotomy for repair of spontaneous CSF leaks is low and the long-term efficacy of repair is high. Universal use of perioperative lumbar drain is not indicated and significantly increases length of stay and hospital costs. Obesity and obstructive sleep apnea are highly associated with spontaneous CSF leaks.
Cochlear implantation is an effective habilitation modality for adults with significant hearing loss. However, post-implant performance is variable. A portion of this variance in outcome can be ...attributed to clinical factors. Recent physiological studies suggest that the health of the spiral ganglion also impacts post-operative cochlear implant outcomes. The goal of this study was to determine whether genetic factors affecting spiral ganglion neurons may be associated with cochlear implant performance.
Adults with post-lingual deafness who underwent cochlear implantation at the University of Iowa were studied. Pre-implantation evaluation included comprehensive genetic testing for genetic diagnosis. A novel score of genetic variants affecting genes with functional effects in the spiral ganglion was calculated. A Z-scored average of up to three post-operative speech perception tests (CNC, HINT, and AzBio) was used to assess outcome.
Genetically determined spiral ganglion health affects cochlear implant outcomes, and when considered in conjunction with clinically determined etiology of deafness, accounts for 18.3% of the variance in postoperative speech recognition outcomes. Cochlear implant recipients with deleterious genetic variants that affect the cochlear sensory organ perform significantly better on tests of speech perception than recipients with deleterious genetic variants that affect the spiral ganglion.
Etiological diagnosis of deafness including genetic testing is the single largest predictor of postoperative speech outcomes in adult cochlear implant recipients. A detailed understanding of the genetic underpinning of hearing loss will better inform pre-implant counseling. The method presented here should serve as a guide for further research into the molecular physiology of the peripheral auditory system and cochlear implants.
•Cochlear implant (CI) outcomes are variable.•We hypothesize that the health of the neural component of the peripheral auditory system is an important factor in CI outcomes.•We show that adult CI users with deleterious mutations that affect the spiral ganglion perform significantly worse on speech recognition testing.•These results may guide pre-operative counseling for adult CI candidates.
The topic of this review is the strategy of preserving residual acoustic hearing in the implanted ear to provide combined electrical stimulation and acoustic hearing as a rehabilitative strategy for ...sensorineural hearing loss. This chapter will concentrate on research done with the Iowa/Nucleus 10
mm Hybrid device, but we will also attempt to summarize strategies and results from other groups around the world who use slightly different approaches. A number of studies have shown that preserving residual acoustic hearing in the implanted ear is a realistic goal for many patients with severe high-frequency hearing loss. The addition of the electric stimulation to their existing acoustic hearing can provide increased speech recognition for these patients. In addition, the preserved acoustic hearing can offer considerable advantages, as compared to a traditional cochlear implant, for tasks such as speech recognition in backgrounds or appreciation of music and other situations where the poor frequency resolution of electric stimulation has been a disadvantage.
This retrospective review explores delayed-onset hearing loss in 85 individuals receiving cochlear implants designed to preserve acoustic hearing at the University of Iowa Hospitals and Clinics ...between 2001 and 2015. Repeated measures of unaided behavioral audiometric thresholds, electrode impedance, and electrically evoked compound action potential (ECAP) amplitude growth functions were used to characterize longitudinal changes in auditory status. Participants were grouped into two primary categories according to changes in unaided behavioral thresholds: (1) stable hearing or symmetrical hearing loss and (2) delayed loss of hearing in the implanted ear. Thirty-eight percent of this sample presented with delayed-onset hearing loss of various degrees and rates of change. Neither array type nor insertion approach (round window or cochleostomy) had a significant effect on prevalence. Electrode impedance increased abruptly for many individuals exhibiting precipitous hearing loss; the increase was often transient. The impedance increases were significantly larger than the impedance changes observed for individuals with stable or symmetrical hearing loss. Moreover, the impedance changes were associated with changes in behavioral thresholds for individuals with a precipitous drop in behavioral thresholds. These findings suggest a change in the electrode environment coincident with the change in auditory status. Changes in ECAP thresholds, growth function slopes, and suprathreshold amplitudes were not correlated with changes in behavioral thresholds, suggesting that neural responsiveness in the region excited by the implant is relatively stable. Further exploration into etiology of delayed-onset hearing loss post implantation is needed, with particular interest in mechanisms associated with changes in the intracochlear environment.
•Delayed-onset hearing loss was observed in 38% of this sample.•A drop in hearing was associated with increasing electrode impedance.•The impedance increase was often noted to be abrupt and transient.•Behavioral threshold changes were not correlated with ECAP changes.
The middle fossa approach is an excellent technique for removing appropriate vestibular schwannomas in patients with serviceable hearing. Knowledge of the intricate middle fossa anatomy is essential ...for optimal outcomes. Gross total removal can be achieved with preservation of hearing and facial nerve function, both in the immediate and long-term periods. This article provides an overview of the background and indications for the procedure, a description of the operative protocol, and a summary of the literature on postoperative hearing outcomes.
Up to 7% of patients with severe-to-profound deafness do not benefit from cochlear implantation. Given the high surgical implantation and clinical management cost of cochlear implantation (>$1 ...million lifetime cost), prospective identification of the worst performers would reduce unnecessary procedures and healthcare costs. Because cochlear implants bypass the membranous labyrinth but rely on the spiral ganglion for functionality, we hypothesize that cochlear implant (CI) performance is dictated in part by the anatomic location of the cochlear pathology that underlies the hearing loss. As a corollary, we hypothesize that because genetic testing can identify sites of cochlear pathology, it may be useful in predicting CI performance.
29 adult CI recipients with idiopathic adult-onset severe-to-profound hearing loss were studied. DNA samples were subjected to solution-based sequence capture and massively parallel sequencing using the OtoSCOPE® platform. The cohort was divided into three CI performance groups (good, intermediate, poor) and genetic causes of deafness were correlated with audiometric data to determine whether there was a gene-specific impact on CI performance.
The genetic cause of deafness was determined in 3/29 (10%) individuals. The two poor performers segregated mutations in TMPRSS3, a gene expressed in the spiral ganglion, while the good performer segregated mutations in LOXHD1, a gene expressed in the membranous labyrinth. Comprehensive literature review identified other good performers with mutations in membranous labyrinth-expressed genes; poor performance was associated with spiral ganglion-expressed genes.
Our data support the underlying hypothesis that mutations in genes preferentially expressed in the spiral ganglion portend poor CI performance while mutations in genes expressed in the membranous labyrinth portend good CI performance. Although the low mutation rate in known deafness genes in this cohort likely relates to the ascertainment characteristics (postlingual hearing loss in adult CI recipients), these data suggest that genetic testing should be implemented as part of the CI evaluation to test this association prospectively.
► We hypothesize the site of the genetic defect impacts cochlear implant outcome. ► We apply comprehensive genetic testing and literature review to test our hypothesis. ► We demonstrate mutations affecting the spiral ganglion portend poor outcome. ► Mutations affecting membranous labyrinth expressed genes portend good outcome. ► Genetic testing should become a standard part of cochlear implant evaluation.
PDF
