Otology & Neurotology - Papers Presented at the Annual Meeting of the German Audiology and Neurotology Group 2014 (ADANO) in Dresden

Special Issue for Papers Presented at the Annual Meeting of the German Audiology and Neurootology Group 2014 (ADANO) in Dresden/Germany No abstract available

What Could Posturography Tell Us About Balance Problems in Parkinson's Disease? Objective: Impaired balance in patients with Parkinson's disease (PD) leads to loss of balance and frequent falls. Computerized dynamic posturography allows the assessment of stance tasks whereas mobile posturography analyzes the balance in free-field conditions, where falls among PD patients commonly occur (e.g. sitting down or standing up). The aim of the present study is to assess postural stability in PD patients with both techniques. Study Design: Prospective study. Setting: University Hospitals, ambulatory care (outpatient clinic). Patients: Thirty-three patients diagnosed with idiopathic PD. Intervention: Balance assessment. Main Outcome Measures: Dizziness handicap inventory (DHI), activities-specific balance confidence scale (ABC), composite score of sensory organization test (SOT), results of free-field body sway analysis (standard balance deficit test (SBDT)), or geriatric SBDT. Results: PD patients showed a significantly higher sway in the roll direction in almost all of the SBDT conditions. Also, pathological sway compared with normative values was more prominent in complex tasks. There is a significant correlation between the different objective variables of the postural study (SOT and SBDT) and the ABC, but not with the DHI. Finally, the percentage of PD patients with a pathological score in SOT-composite score was 54.5% whereas in SBDT-composite score it was significantly higher (93.9%). Conclusion: Mobile posturography is more accurate in depicting the reality of balance impairment in PD patients than platform posturography. Also, ABC relates better than DHI to the significant psychological consequences of balance impairments. An increased lateral trunk sway seems to be a key factor of postural instability in PD patients.

Functional Result After Cochlear Implantation in Children and Adults With Single-sided Deafness Background: Patients with single-sided deafness (SSD) suffer from reduced binaural hearing (i.e., sound localization and speech in noise discrimination). Cochlear implantation has recently been introduced for patients with SSD, as an alternative to hearing devices that employ contralateral routing of the signal. Application to children has also been started. Methods: We retrospectively analyze a case series of 4 children and 17 adults with SSD, treated with cochlear implantation. The outcome of adult patients was compared with a control group of 27 patients with bilateral profound hearing loss using a cochlear implant. Results: During 12 months, the mean speech recognition score increased from 30 to 41% for monosyllabic words in adults, and from 58 to 89% for multisyllabic numbers. The cochlear implant (CI) improved hearing in noise in all SSD patients, as was demonstrated by a significant improvement of the speech reception threshold in different speech and noise configurations. Sound localization-correlated angle detection error improved with CI use at every time point. The maximum word recognition score for monosyllabic words in quiet correlated with the logarithm of the duration of deafness; improvement of the speech reception threshold and RMS angle detection error by the CI did not. Conclusion: All SSD patients benefitted from the CI in different hearing situations. Patients with SSD for a long period can improve after cochlear implantation.

Management of Cochlear Implant Electrode Migration Objective: The present study reviewed a cochlear implant (CI) patient population after surgery, which received a free-fitting electrode carrier designed for hearing preservation. The aim was to determine the rate of electrode migration of the CI electrodes and present clinical and surgical implications. Study Design: Retrospective patient review. Setting: Tertiary referral university hospital. Patients: Two hundred seventy-eight patients implanted uni- or bilaterally with lateral wall electrodes designed for hearing preservation (358 implants). The control group was 323 patients implanted uni- or bilaterally with preformed perimodiolar electrodes (468 implants). Interventions: Determination of CI electrode migration was conducted according to a clinical test protocol. Revision surgery was offered in confirmed patients of electrode migration. A bone groove was considered to improve the fixation of the electrode. Main Outcome Measures: Audiological testing including speech audiometry, subjective sound quality rating, and bilateral pitch comparison in bilateral patients, as well as radiological examinations, were conducted. Results: Electrode migration was observed solely in patients implanted with lateral wall electrodes; 10 of 358 patients with free-fitting electrodes (2.8%) had electrode migration, which was successfully confirmed by the proposed clinical test protocol. Nine of the 10 confirmed patients underwent reinsertion surgery. Mean perception score decreased from 75.0% to 62.1% after electrode migration and recovered completely after reinsertion surgery. A flowchart to detect electrode migration was designed for clinical practice. Conclusion: Although electrode migration is a rare complication in CI surgery, long-term follow-up diagnostics should include a test protocol to detect electrode shifts of lateral wall electrode arrays. A reinsertion surgery should be conducted in confirmed patients to recover speech perception.

Hearing Preservation With a Midscalar Electrode Comparison of a Regular and Steroid/Pressure Optimized Surgical Approach in Patients With Residual Hearing Objective: The aim of this study was to observe the rate of hearing preservation with a midscalar electrode with two surgical approaches. Study Design: Prospective study. Setting: Tertiary referral center. Patients: Twenty patients with residual hearing. Group A: 11 patients (mean age 56.1, 4 men, 7 women) mean HL 250 Hz, 36.4 dB; 500 Hz, 50.0 dB and 1 kHz, 81.4 dB. Group B: nine patients (mean age, 52.8 yr, 7 women, 2 men), 250 Hz, 36.7 dB; 500 Hz, 49.4 dB and 1 kHz, 87.8 dB. Intervention: Implantation with a midscalar electrode with two surgical approaches. Group A approach consisted of a slow insertion (2 min), careful round window opening, tool insertion, intraoperative and postoperative iv. prednisone, tool insertion and 24 hour postoperation bed-rest. In group B additionally the round window was widely opened and the electrode was wetted with triamcinolone. Main Outcome Measure: Measurement of the mean hearing loss in both groups. Results: We observed a statistically significant different hearing preservation for groups A and B. Although group A reached a mean hearing loss (250, 500, 1 kHz) of 42.6 dB, group B showed a mean loss of residual hearing of 9.1 dB after 1 month. Conclusion: A substantial rate of hearing preservation can be achieved with a midscalar electrode. A hearing preserving approach focusing on decreasing the intracochlear fluid pressure and local steroids has a strong effect on the hearing preservation.

Long-term Hearing Preservation Outcomes After Cochlear Implantation for Electric-Acoustic Stimulation Objective: This study reviewed outcomes of hearing preservation (HP) surgery in a cochlear implant patient population, with clinical follow-up results up to 11 years after implantation. Study Design: Retrospective case review. Setting: Tertiary referral university hospital. Patients: Ninety six patients (103 ears) with partial deafness who underwent HP surgery at the University Hospital Frankfurt since 1999 were included. Electrode carriers were Cochlear Slim Straight, MED-EL Standard, Medium, Flex20, and Flex24. Intervention: Cochlear implantation using the HP surgery technique with either the cochleostomy or round window approach. Main Outcome Measures: Pure-tone averages for low frequencies (125 Hz, 250 Hz, 500 Hz, PTAlow) and speech perception scores of the Freiburg monosyllable and number tests in quiet. PTAlow shifts were used to evaluate HP as complete for ≤10 dB, partial between 10 and 30 dB, and minimal for ≥30 dB. Time intervals were: preoperative, postoperative, after 12 months, and long-term (>24 months, mean 51.4 months, range 2–11 years). Impacts of electrode design and surgical approach were analyzed. Results: Postoperatively (n = 103), HP was complete in 32 (31.1%), partial in 49 (47.6%), minimal in 14 (13.6%), and loss of hearing occurred in 8 cases (7.8%). After 12 months (n = 81), HP was complete in 22 (27.2%), partial in 33 (40.7%), minimal in 11 (13.6%), and loss of hearing occurred in 7 additional cases. For long-term outcomes (n = 62) HP was complete in 7 (11.3%), partial in 24 (38.7%), minimal in 9 (14.5%), and loss of hearing occurred in 7 additional cases (total 22/103, 21.4%). Cases with residual hearing who could utilize acoustic amplification (i.e., PTAlow < 80 dB HL) were 82/95 (85.3%) postoperatively, 58/66 (87.9%) after 12 months, and 38/40 (95.0%) for long-term outcomes. Conclusions: Long-term HP is feasible in a subset of patients. Patients with sufficient long-term residual hearing had the prerequisite to benefit from additional acoustic stimulation. No correlation of total hearing loss with etiology, electrode design, or surgical approach was evident. Apart from individual effects of structural damage or inflammation, genetic factors are suggested to influence HP. Cases with total hearing loss still demonstrated successful speech perception in long-term monosyllable recognition scores.

Adult Cochlear Implant Users Are Able to Discriminate Basic Tonal Features in Musical Patterns: Evidence From Event-related Potentials Objective: Measurement of electrophysiological correlates of discrimination abilities of basic musical features in pre- and postlingually deafened adult cochlear implant (CI) users. Study Design: Electroencephalographic study. Comparison between CI users and matched normal hearing controls. Patients: Thirty-six hearing impaired adults using a cochlear implant for 4 to 15 months. Profound hearing impairment was acquired either before (N = 12) or after language acquisition (N = 17). Seven patients suffered from a single-sided deafness. Methods: Presentation of auditory stimuli consisting of musical four tone standard patterns and deviant patterns varying with regard to tone pitch, timbre, intensity, and rhythm of two different degrees. Analysis of electrophysiological, event-related mismatch responses. Results: Cochlear implant users elicited significant mismatch responses on most deviant features. Comparison to controls revealed significantly smaller mismatch negativity amplitudes. Except for one parameter (pitch) there were no reliable differences between pre- and postlingually deafened CI users. Conclusion: Despite a highly reduced complexity of neural auditory stimulation by the cochlear implant device in comparison to the physiological cochlear input, CI users exhibit cortical discriminatory responses to relatively subtle basic tonal alterations.

Impact of Prosthesis Length on Tympanic Membrane's and Annular Ligament's Stiffness and the Resulting Middle Ear Sound Transmission Hypothesis: Prosthesis' length creates tension in ossicular reconstructions, which directly effects the middle ear sound transmission. Background: Relatively long prostheses are often used to stabilize the middle ear reconstruction to prevent dislocation. Thereby, tension on the flexible components such as the tympanic membrane (TM) and the annular ligament (AL) is increased. Only little is known on the amount of displacement-related stiffening of the TM and AL, as well as the consecutive reduction in middle ear transfer function (METF). Methods: An expandable total ossicular replacement prosthesis was tensionfree inserted in nine cadaveric temporal bones between the malleus handle and the stapes footplate. Upon heat activation the prosthesis was lengthened, thus inducing tension on the reconstruction. The METF was assessed before and after elongation. TM's and AL's stiffness were determined by measuring their force–displacement characteristics. Results: Upon activation the prostheses were elongated between 50 and 200 μm. A frequency-dependent METF reduction was measured with a decrease of 5 to 25 dB below 1.0 kHz. At frequencies >2.0 kHz the reduction was less prominent or the METF showed even an improvement of up to 10 dB. TM's stiffness remained constant during the elongation-induced displacement, whereas the AL's stiffness increased. The METF reduction below 1.0 kHz correlated with the increasing AL's stiffness. Conclusion: Tension has a significant impact on the METF after middle ear reconstruction. As little tension as possible should be used to enable best sound transmission. Stabilization of prosthesis should be achieved with dislocation devices to ensure secure coupling to the ossicular remnants without creating additional tension.

Adaptive Mechanical Stabilization of a Free-Floating Fully Implantable Hearing Aid Hypothesis: An implantable acousto-mechanical transducer will yield a higher output if its mass can be virtually increased through the use of a secondary actuator. Background: Current hearing aids and implants rely on feedback compensation to prevent instability (e.g. howling), usually in the form of a digital or analogue filter. We examine the effect of mechanically stabilizing a piezo-driven mechanical amplifier inserted into the incudostapedial joint gap. The aim of this study is to determine whether this is possible and discern the advantages and disadvantages of the design. Methods: We examine a 10:1 scale model of a prospective implantable hearing aid comprising one piezoelectric sensor and two independent piezoelectric actuators in a single-titanium housing. As expected, the maximum gain of the device is limited by feedback between sensor input and the output of the primary actuator. The secondary actuator is used to provide a counter force to the recoil of the primary output piezo. This adds a virtual mass to the device, effectively reducing feedback in the mechano-acoustic path. The compensation unit (CU) described here is driven by a real-time adaptive control algorithm. Results: Using the above approach, we observe an added stable gain of >30 dB, and report a functional hearing gain of up to 40 dB. Physical and digital feedback compensation can be employed in parallel for best results. The experimental data is backed by computer simulations. Conclusion: These results compare favorably with previous studies of a two-piezo transducer with digital feedback control and show the potential for the transducer as a hearing aid for high-frequency hearing loss.

Intracranial Pressure and Promontory Vibration With Soft Tissue Stimulation in Cadaveric Human Whole Heads Hypothesis: Intracranial pressure and skull vibrations are correlated and depend on the stimulation position and frequency. Background: A hearing sensation can be elicited by vibratory stimulation on the skin covered skull, or by stimulation on soft tissue such as the neck. It is not fully understood whether different stimulation sites induce the skull vibrations responsible for the perception or whether other transmission pathways are dominant. The aim of this study was to assess the correlation between intracranial pressure and skull vibration measured on the promontory for stimulation to different sites on the head. Methods: Measurements were performed on four human cadaver heads. A bone conduction hearing aid was held in place with a 5-Newton steel headband at four locations (mastoid, forehead, eye, and neck). While stimulating in the frequency range of 0.3 to 10 kHz, acceleration of the cochlear promontory was measured with a Laser Doppler Vibrometer, and intracranial pressure at the center of the head with a hydrophone. Results: Promontory acceleration and intracranial pressure was measurable for all stimulation sites. The ratios were comparable between all stimulation sites for frequencies below 2 kHz. Conclusion: These findings indicate that both promontory acceleration and intracranial pressure are involved for stimulation on the sites investigated. The transmission pathway of sound energy is comparable for the four stimulation sites.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
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6948891480

alsfakia@gmail.com