Profound Sensory Hearing Loss Research Articles

Robotic assistance during cochlear implantation: the rationale for consistent, controlled speed of electrode array insertion.

Cochlear implants (CI) have revolutionized the treatment of patients with severe to profound sensory hearing loss by providing a method of bypassing normal hearing to directly stimulate the auditory nerve. A further advance in the field has been the introduction of "hearing preservation" surgery, whereby the CI electrode array (EA) is carefully inserted to spare damage to the delicate anatomy and function of the cochlea. Preserving residual function of the inner ear allows patients to receive maximal benefit from the CI and to combine CI electric stimulation with acoustic hearing, offering improved postoperative speech, hearing, and quality of life outcomes. However, under the current paradigm of implant surgery, where EAs are inserted by hand, the cochlea cannot be reliably spared from damage. Robotics-assisted EA insertion is an emerging technology that may overcome fundamental human kinetic limitations that prevent consistency in achieving steady and slow EA insertion. This review begins by describing the relationship between EA insertion speed and generation of intracochlear forces and pressures. The various mechanisms by which these intracochlear forces can damage the cochlea and lead to worsened postoperative outcomes are discussed. The constraints of manual insertion technique are compared to robotics-assisted methods, followed by an overview of the current and future state of robotics-assisted EA insertion.

Factors Influencing Pediatric Cochlear Implant Outcomes: Carolina Sibling Study.

To determine the correlation between speech perception performance between pediatric sibling pairs with severe to profound sensory hearing loss receiving cochlear implants, and in cases of discordance in performance, determine which variables negatively impacted performance. Retrospective chart review. Tertiary academic referral center. Eighty-nine pediatric subjects, 43 sibling groups, under the age of 18 with severe to profound sensory hearing loss who received a cochlear implant with a sibling who also received a cochlear implant. Cochlear implantation. Speech perception scores, consonant-nucleus- consonant score. A statistically significant correlation was found between speech perception performance of pediatric siblings. Depth of insertion is positively correlated with better speech perception in siblings with discordant results. There was no significant relationship with either electrode type, unilateral/bilateral status, or age of implantation. Pediatric siblings have a high correlation in speech perception outcomes following cochlear implantation, suggesting family environment plays a strong role. In circumstances in which outcomes between siblings are substantially different, greater depth of implant insertion is correlated with better consonant-nucleus- consonant word scores.

The outcome of our modified double-flap technique for cochlear implantation: A case series of 342 consecutive patients

ObjectivesA lazy S-shaped postauricular incision with a modified double-flap technique has been used for cochlear implant surgery at our institution for the past 10 years. The postoperative surgical complications, morbidity, and outcome of this technique were evaluated.MethodsA retrospective case review was conducted in a tertiary referral teaching center. A total of 342 patients with profound sensory hearing loss (173 female and 169 male subjects; age range, 11 months to 52 years) who underwent cochlear implantation using the double-flap postauricular transmastoid surgical approach during a 5-year period (2005 through 2009) with at least 5 years' follow-up were retrospectively evaluated. Postoperative wound complications were identified. Major complications included flap necrosis, wound infection requiring surgical intervention, and wound dehiscence with or without implant exposure. Swelling over the implant and superficial wound infections treated medically were considered minor complications. Other non-wound-related complications, surgical time, and number of electrodes inserted were also recorded.ResultsThe surgical approach was accomplished in all the patients with four minor wound complications. The mean surgical time was 1.4 hours, and the mean time between surgery and the programming process was 2 weeks.ConclusionThis modified double-flap technique was easy to perform and appeared to reduce the incidence of wound complications in cochlear implant surgery. It allowed programming of the implant after a shorter period of time.

HEARING, PSYCHOPHYSICS, AND COCHLEAR IMPLANTATION: EXPERIENCES OF OLDER INDIVIDUALS WITH MILD SLOPING TO PROFOUND SENSORY HEARING LOSS

In a previous paper we reported the frequency selectivity, temporal resolution, nonlinear cochlear processing, and speech recognition in quiet and in noise for 5 listeners with normal hearing (mean age 24.2 years) and 17 older listeners (mean age 68.5 years) with bilateral, mild sloping to profound sensory hearing loss (Gifford et al., 2007). Since that report, 2 additional participants with hearing loss completed experimentation for a total of 19 listeners. Of the 19 with hearing loss, 16 ultimately received a cochlear implant. The purpose of the current study was to provide information on the pre-operative psychophysical characteristics of low-frequency hearing and speech recognition abilities, and on the resultant postoperative speech recognition and associated benefit from cochlear implantation. The current preoperative data for the 16 listeners receiving cochlear implants demonstrate: 1) reduced or absent nonlinear cochlear processing at 500 Hz, 2) impaired frequency selectivity at 500 Hz, 3) normal temporal resolution at low modulation rates for a 500-Hz carrier, 4) poor speech recognition in a modulated background, and 5) highly variable speech recognition (from 0 to over 60% correct) for monosyllables in the bilaterally aided condition. As reported previously, measures of auditory function were not significantly correlated with pre- or post-operative speech recognition - with the exception of nonlinear cochlear processing and preoperative sentence recognition in quiet (p=0.008) and at +10 dB SNR (p=0.007). These correlations, however, were driven by the data obtained from two listeners who had the highest degree of nonlinearity and preoperative sentence recognition. All estimates of postoperative speech recognition performance were significantly higher than preoperative estimates for both the ear that was implanted (p<0.001) as well as for the best-aided condition (p<0.001). It can be concluded that older individuals with mild sloping to profound sensory hearing loss have very little to no residual nonlinear cochlear function, resulting in impaired frequency selectivity as well as poor speech recognition in modulated noise. These same individuals exhibit highly significant improvement in speech recognition in both quiet and noise following cochlear implantation. For older individuals with mild to profound sensorineural hearing loss who have difficulty in speech recognition with appropriately fitted hearing aids, there is little to lose in terms of psychoacoustic processing in the low-frequency region and much to gain with respect to speech recognition and overall communication benefit. These data further support the need to consider factors beyond the audiogram in determining cochlear implant candidacy, as older individuals with relatively good low-frequency hearing may exhibit vastly different speech perception abilities - illustrating the point that signal audibility is not a reliable predictor of performance on supra-threshold tasks such as speech recognition.

Auditory and vestibular manifestations of Vogt–Koyanagi–Harada disease

Vogt-Koyanagi-Harada disease is a chronic disorder involving the eye and the central nervous, auditory, vestibular and integumentary systems. This study aimed to determine the auditory and vestibular manifestations of this disease. Twenty-four patients diagnosed with Vogt-Koyanagi-Harada disease were assessed for auditory and vestibular dysfunction. Uveitis presents in all cases. Sensory hearing loss was present in 50 per cent of cases, tinnitus in 42 per cent, vertigo in 17 per cent and headache in 17 per cent. Nine patients received systemic steroids. Six patients who were treated early regained their hearing, but three patients whose treatment was delayed did not. One patient with bilateral profound hearing loss underwent cochlear implantation, and achieved excellent post-implantation hearing. There is a high incidence of cochlear and vestibular end-organ involvement in patients with Vogt-Koyanagi-Harada disease. The adequacy and timing of treatment has a significant effect on the disease outcome. Vogt-Koyanagi-Harada disease appears to affect the inner ear end-organ. Patients who develop bilateral profound sensory hearing loss are suitable candidates for cochlear implantation.

Suprameatal approach for cochlear implantation in 45 Chinese children

To investigate the feasibility of applying the suprameatal approach (SMA) for cochlear implantation in Chinese children with profound sensory hearing loss, and to demonstrate a technical modification incorporated in the procedure due to an observed racial difference. Retrospective study. University hospital. Forty-five Chinese children (total 47 ears) with profound sensory hearing loss were surgically treated from May 2005 to May 2006. The patients were followed anywhere from 1 month to 20 months post-surgery, with 30 patients being followed for more than 6 months. All patients received cochlear implantation through the suprameatal approach. In this procedure, the cochleostomy was performed in one stage after the suprameatal tunnel was finished, rather than the two-stage approach described by Kronenberg (who firstly introduced the suprameatal approach). Three patients with low-lying dura (which is considered to be the contraindication for cochlear implantation with SMA) were treated with a further modified surgical approach. Among the 47 ears, full electrode pairs were completely inserted in 45 ears without surgical difficulties, but 1 ear was only fitted with 9 pairs of electrodes because of an ossified cochlea, and another with just 8 pairs of electrodes due to serious cochlear dysplasia. An intraoperative "gusher" occurred in the dysplasia case, and a small piece of temporalis muscle was used, along with biology glue, to seal the cochleostomy and prevent further leakage. In 1 case, the electrode was inserted into the cochlea through the tunnel lateral to the chorda tympani because adhesion had occurred between the incus and chorda tympani. There were no postoperative complications in any case. Thirty cases exhibited better hearing or speech development from cochlear implantation after more than 6 months of follow-up. The SMA was found to be a simple and safe technique for cochlear implantation in Chinese children. It enables wide exposure of the middle ear, and is especially suitable for cases with a narrow facial recess, an anteriorly located facial nerve, or an ossified cochlea. It is almost impossible to injure the facial nerve or the chorda tympani nerve. The cochleostomy can be performed in one stage in those patients with a normal cochlea. With some modifications, a low-lying dura will not be the absolute contraindication of SMA.

Paediatric cochlear implantation.

Cochlear implantation may now be considered as a method of managing children with profound sensory hearing loss who do not benefit from conventional amplification. It involves a team approach with integration of many skilled individuals, as well as the child and his or her parents and family. As William House has said, in 1991, 'The future is not in the adult programme, but in the continued expansion of the children's programme'.

Ultrastructure of the vestibular sensory organs in delayed endolymphatic hydrops

Vestibular sensory organs were examined ultrastructurally in two cases of delayed endolymphatic hydrops. The patients, two women, 27 and 16 years of age, suffered profound sensory hearing loss in childhood and experienced severe, recurrent vertigo. Specimens were obtained by a translabyrinthial vestibular nerve transection. We studied the utricular macula and the lateral and posterior cristae in one case, and the utricular macula, the anterior and posterior cristae, and the vestibular ganglion in the other. The otoconia and the otoconial membrane, the sensory epithelia, and the vestibular ganglion appeared fairly normal. Although the entire vestibular end organs were not studied in these cases, it was surprising that the ultrastructural findings did not conclusively identify vestibular end organ pathology as the cause of the vertigo attacks.

Results for Chinese and English in a Multichannel Cochlear Implant Patient

A multichannel cochlear prosthesis was implanted in a Chinese patient who suffered from profound sensory hearing loss. The preoperative Minimal Auditory Capabilities (MAC) battery tests in English, as well as an open set bisyllable word test, an open set sentence test, and speech tracking in Chinese indicated significant improvement of speech perception for both English and Chinese after the operation. Substantial understanding of running speech was possible in both languages without the help of lipreading.

Current Status and Problems of Cochlear Implant

At the present time there is no defined treatment for profound sensory hearing loss. Clinically, it is possible to stimulate the remaining auditory nerve fibers by electronic devices (cochlear implant) in order to restore hearing. This paper will give an outline of the current status of cochlear implant.The electronic devices that receive their input from a microphone/amplifier system and send their output to the implanted electrodes are classifed into the following three systems: 1) percutaneous transmission system, 2) transcutaneous transmission system, and 3) implantable package system. Two locations, the scala tympani and modiolus, are reported as suitable sites for cochlear implant. The scala tympani approach takes advantage of the cochlea's tonotopic organization to stimulate the auditory nerve fibers selectively, though it is limited by the current shunting in the cochlear fluid The modiolar approach permits access to the fibers coming from all parts of the cochlea, though selective stimulation of small groups of fibers is difficult. It is proved that a cochlear implant with a single channel system is useful only as an aid to lip reading and for distinguishing some environmental sounds. To improve speech discrimination, a multichannel system is indispensable, though it is unknown how many channels may be necessary in order to provide intelligible speech. The indication of the cochlear implant is assessed by the electrical promontory or round window stimulation test. The etiopathological backgrounds considered suitable for implantation are deafnesses caused by ototoxic drugs or head trauma, hereditary sensory deafness of adult onset, and advanced bilateral Meniere's disease.