[Extended preoperative speech audiometric diagnostics for cochlear implant treatment]

BACKGROUND

For severe hearing loss and even profound deafness, cochlear implants (CIs) have become the treatment of choice. For establishment of the CI indication, the preoperative Freiburger monosyllabic word recognition (EV) at 65 dB SPL in free field with a hearing aid (EVHG65) and the maximal understanding (mEV) without a hearing aid with headphones results are important. The goal of this retrospective study was to analyse the correlation of word recognition with a hearing aid at 80 dB SPL (EVHG80) and mEV. This represents an extension to measuring EVHG65 compared to mEV and to pure-tone audiometry (4FPTA).

METHODS

In this study, word recognition with and without a hearing aid was retrospectively analysed for 661 ears. Inclusion criterium was CI implantation at a later date.

RESULTS

During preoperative CI diagnostics, an mEV of 0% was found in 334 ears. The EVHG65 for 485 ears and the EVHG80 for 335 ears were also 0%. The EV with hearing aid was found to worsen with increasing 4FPTA at both sound pressure levels, although this effect was smaller at 80 dB SPL than at 65 dB SPL. Including only ears with mEV > 0 % (N = 260 ears), a stronger correlation between EVHG80 and mEV with a difference of (-4.0 ± 16.4%) in comparison to EVHG65 and mEV with a difference of (-18.3 ± 16.7%) is seen. This shows a significant difference between mEV and EVHG80 compared to mEV and EVHG65.

CONCLUSION

At a sound pressure level of 65 dB SPL, EV with hearing aid often does not show the accordance with mEV specified by hearing aid and CI guidelines. The EVHG80 correlates better with mEV than EVHG65. For clinical diagnosis it is rational to measure speech discrimination with hearing aid at levels higher than 65 dB SPL.

Optimizing the efficiency of ECAP measurements due to interpolation

BACKGROUND

Thresholds of electrically evoked compound action potentials (TECAP) may serve as starting points for electrophysiologically based fitting of cochlear implants. Absent TECAP data at single electrodes reduces the number of data points available for fitting and can be substituted by interpolation of measured data points.

AIM

To compare complete TECAP profiles with interpolated TECAP profiles of 5/22 (∼22.7%) and 11/22 (50%) electrode contacts.

MATERIAL AND METHODS

Single-centre, retrospective, observational study of data from 624 ears implanted with a Slim Modiolar (CI ×32) or Contour Advance (CI ×12, CI24RE(CA)) electrode array (Cochlear Ltd). The deviation of the complete measured TECAP profile from the same profile with missing and therefore interpolated TECAP values was quantified.

RESULTS

Interpolated TECAP profiles significantly differ from complete measured profiles especially at the basal and apical electrodes. Reference data for Slim Modiolar and Contour Advance electrodes mean profiles are provided.

CONCLUSIONS AND SIGNIFICANCE

Reducing the number of measured TECAP electrodes has to be weighted against losses in the TECAP accuracy of interpolated values. A clinically acceptable compromise may be a reduction from 22 to 11 even non-equidistant data points. While reducing ECAP measurement time, it is accompanied by a minimal loss of accuracy of the TECAP threshold profile.

Facilitation properties in electrically evoked compound action potentials depending on spatial location and on threshold

Spiral ganglion neurons (SGNs) facilitation properties can be recorded utilizing electrically evoked compound action potential (ECAP). While intracochlear variation of the ECAP threshold in relation to its electrode channel is reported, no study investigated its impact on facilitation. In this study, we quantified intracochlear variation of the facilitation properties in cochlear implants (CI) using ECAPs. We hypothesized that the facilitation effect is dependent on the electrode channel and its ECAP threshold. Therefore, ECAPs were recorded in 23 CI subjects. For each subject, five default (channel-derived) and up to two additional (threshold-derived) stimulation sites were defined. Facilitation was quantified by the paradigm introduced by (Hey et al., 2017) with optimized parameter settings. For each channel the maximum facilitated amplitude was determined by a series of ECAP measurements. A linear mixed-effects model was used to investigate the impact of the electrode channel and ECAP threshold on the maximum facilitated amplitude. The maximum facilitated amplitude was found to be dependent on the ECAP threshold and independent on the electrode channel. We conclude that the facilitation paradigm is a useful and feasible tool to gain local information on the SGNs temporal processing patterns.

Evaluation of CI electrode position from imaging: comparison of an automated technique with the established manual method

BACKGROUND

A manual evaluation of the CI electrode position from CT and DVT scans may be affected by diagnostic errors due to cognitive biases. The aim of this study was to compare the CI electrode localization using an automated method (image-guided cochlear implant programming, IGCIP) with the clinically established manual method.

METHODS

This prospective experimental study was conducted on a dataset comprising N=50 subjects undergoing cochlear implantation with a Nucleus® CI532 or CI632 Slim Modiolar electrode. Scalar localization, electrode-to-modiolar axis distances (EMD) and angular insertion depth (aDOI) were compared between the automated IGCIP tool and the manual method. Two raters made the manual measurements, and the interrater reliability (±1.96·SD) was determined as the reference for the method comparison. The method comparison was performed using a correlation analysis and a Bland-Altman analysis.

RESULTS

Concerning the scalar localization, all electrodes were localized both manually and automatically in the scala tympani. The interrater differences ranged between ±0.2 mm (EMD) and ±10° (aDOI). There was a bias between the automatic and manual method in measuring both localization parameters, which on the one hand was smaller than the interrater variations. On the other hand, this bias depended on the magnitude of the EMD respectively aDOI. A post-hoc analysis revealed that the deviations between the methods were likely due to a different selection of mid-modiolar axis.

CONCLUSIONS

The IGCIP is a promising tool for automated processing of CT and DVT scans and has useful functionality such as being able to segment the cochlear using post-operative scans. When measuring EMD, the IGCIP tool is superior to the manual method because the smallest possible distance to the axis is determined depending on the cochlear turn, whereas the manual method selects the helicotrema as the reference point rigidly. Functionality to deal with motion artifacts and measurements of aDOI according to the consensus approach are necessary, otherwise the IGCIP is not unrestrictedly ready for clinical use.

Speech comprehension in noise-considerations for ecologically valid assessment of communication skills ability with cochlear implants

BACKGROUND

Nowadays, cochlear implant (CI) patients mostly show good to very good speech comprehension in quiet, but there are known problems with communication in everyday noisy situations. There is thus a need for ecologically valid measurements of speech comprehension in real-life listening situations for hearing-impaired patients. The additional methodological effort must be balanced with clinical human and spatial resources. This study investigates possible simplifications of a complex measurement setup.

METHODS

The study included 20 adults from long-term follow-up after CI fitting with postlingual onset of hearing impairment. The complexity of the investigated listening situations was influenced by changing the spatiality of the noise sources and the temporal characteristics of the noise. To compare different measurement setups, speech reception thresholds (SRT) were measured unilaterally with different CI processors and settings. Ten normal-hearing subjects served as reference.

RESULTS

In a complex listening situation with four loudspeakers, differences in SRT from CI subjects to the control group of up to 8 dB were found. For CI subjects, this SRT correlated with the situation with frontal speech signal and fluctuating interference signal from the side with R2 = 0.69. For conditions with stationary interfering signals, R2 values <0.2 were found.

CONCLUSION

There is no universal solution for all audiometric questions with respect to the spatiality and temporal characteristics of noise sources. In the investigated context, simplification of the complex spatial audiometric setting while using fluctuating competing signals was possible.

Extended Preoperative Audiometry for Outcome Prediction and Risk Analysis in Patients Receiving Cochlear Implants

BACKGROUND

The outcome of cochlear implantation has improved over the last decades, but there are still patients with less benefit. Despite numerous studies examining the cochlear implant (CI) outcome, variations in speech comprehension with CI remains incompletely explained. The aim of this study was therefore to examine preoperative pure-tone audiogram and speech comprehension as well as aetiology, to investigate their relationship with postoperative speech comprehension in CI recipients.

METHODS

A retrospective study with 664 ears of 530 adult patients was conducted. Correlations between the target variable postoperative word comprehension with the preoperative speech and sound comprehension as well as aetiology were investigated. Significant correlations were inserted into multivariate models. Speech comprehension measured as word recognition score at 70 dB with CI was analyzed as (i) a continuous and (ii) a dichotomous variable.

RESULTS

All variables that tested preoperative hearing were significantly correlated with the dichotomous target; with the continuous target, all except word comprehension at 65 dB with hearing aid. The strongest correlation with postoperative speech comprehension was seen for monosyllabic words with hearing aid at 80 dB. The preoperative maximum word comprehension was reached or surpassed by 97.3% of CI patients. Meningitis and congenital diseases were strongly negatively associated with postoperative word comprehension. The multivariate model was able to explain 40% of postoperative variability.

CONCLUSION

Speech comprehension with hearing aid at 80 dB can be used as a supplementary preoperative indicator of CI-aided speech comprehension and should be measured regularly in the clinical routine. Combining audiological and aetiological variables provides more insights into the variability of the CI outcome, allowing for better patient counselling.

Comparisons of electrophysiological and psychophysical fitting methods for cochlear implants

OBJECTIVE

This study compared two different versions of an electrophysiology-based software-guided cochlear implant fitting method with a procedure employing standard clinical software. The two versions used electrically evoked compound action potential (ECAP) thresholds for either five or all twenty-two electrodes to determine sound processor stimulation level profiles. Objective and subjective performance results were compared between software-guided and clinical fittings.

DESIGN

Prospective, double-blind, single-subject repeated-measures with permuted ABCA sequences.

STUDY SAMPLE

48 post linguistically deafened adults with ≤15 years of severe-to-profound deafness who were newly unilaterally implanted with a Nucleus device.

RESULTS

Speech recognition in noise and quiet was not significantly different between software- guided and standard methods, but there was a visit/learning-effect. However, the 5-electrode method gave scores on the SSQ speech subscale 0.5 points lower than the standard method. Clinicians judged usability for all methods as acceptable, as did subjects for comfort. Analysis of stimulation levels and ECAP thresholds suggested that the 5-electrode method could be refined.

CONCLUSIONS

Speech recognition was not inferior using either version of the electrophysiology-based software-guided fitting method compared with the standard method. Subject-reported speech perception was slightly inferior with the five-electrode method. Software-guided methods saved about 10 min of clinician's time versus standard fittings.

[Speech comprehension in noise-considerations for ecologically valid assessment of communication skills ability with cochlear implants. German version]

BACKGROUND

Nowadays, cochlear implant (CI) patients mostly show good to very good speech comprehension in quiet, but there are known problems with communication in everyday noisy situations. There is thus a need for ecologically valid measurements of speech comprehension in real-life listening situations for hearing-impaired patients. The additional methodological effort must be balanced with clinical human and spatial resources. This study investigates possible simplifications of a complex measurement setup.

METHODS

The study included 20 adults from long-term follow-up after CI fitting with postlingual onset of hearing impairment. The complexity of the investigated listening situations was influenced by changing the spatiality of the noise sources and the temporal characteristics of the noise. To compare different measurement setups, speech reception thresholds (SRT) were measured unilaterally with different CI processors and settings. Ten normal-hearing subjects served as reference.

RESULTS

In a complex listening situation with four loudspeakers, differences in SRT from CI subjects to the control group of up to 8 dB were found. For CI subjects, this SRT correlated with the situation with frontal speech signal and fluctuating interference signal from the side with R2 = 0.69. For conditions with stationary interfering signals, R2 values <0.2 were found.

CONCLUSION

There is no universal solution for all audiometric questions with respect to the spatiality and temporal characteristics of noise sources. In the investigated context, simplification of the complex spatial audiometric setting while using fluctuating competing signals was possible.

Ecological Momentary Assessment to Obtain Signal Processing Technology Preference in Cochlear Implant Users

Background: To assess the performance of cochlear implant users, speech comprehension benefits are generally measured in controlled sound room environments of the laboratory. For field-based assessment of preference, questionnaires are generally used. Since questionnaires are typically administered at the end of an experimental period, they can be inaccurate due to retrospective recall. An alternative known as ecological momentary assessment (EMA) has begun to be used for clinical research. The objective of this study was to determine the feasibility of using EMA to obtain in-the-moment responses from cochlear implant users describing their technology preference in specific acoustic listening situations. Methods: Over a two-week period, eleven adult cochlear implant users compared two listening programs containing different sound processing technologies during everyday take-home use. Their task was to compare and vote for their preferred program. Results: A total of 205 votes were collected from acoustic environments that were classified into six listening scenes. The analysis yielded different patterns of voting among the subjects. Two subjects had a consistent preference for one sound processing technology across all acoustic scenes, three subjects changed their preference based on the acoustic scene, and six subjects had no conclusive preference for either technology. Conclusion: Results show that EMA is suitable for quantifying real-world self-reported preference, showing inter-subject variability in different listening environments. However, there is uncertainty that patients will not provide sufficient spontaneous feedback. One improvement for future research is a participant forced prompt to improve response rates.

Quality-assured training in the evaluation of cochlear implant electrode position: a prospective experimental study

BACKGROUND

The objective of this study was to demonstrate the utility of an approach in training predoctoral medical students, to enable them to measure electrode-to-modiolus distances (EMDs) and insertion-depth angles (aDOIs) in cochlear implant (CI) imaging at the performance level of a single senior rater.

METHODS

This prospective experimental study was conducted on a clinical training dataset comprising patients undergoing cochlear implantation with a Nucleus® CI532 Slim Modiolar electrode (N = 20) or a CI512 Contour Advance electrode (N = 10). To assess the learning curves of a single medical student in measuring EMD and aDOI, interrater differences (senior-student) were compared with the intrarater differences of a single senior rater (test-retest). The interrater and intrarater range were both calculated as the distance between the 0.1th and 99.9th percentiles. A "deliberate practice" training approach was used to teach knowledge and skills, while correctives were applied to minimize faulty data-gathering and data synthesis.

RESULTS

Intrarater differences of the senior rater ranged from - 0.5 to 0.5 mm for EMD and - 14° to 16° for aDOI (respective medians: 0 mm and 0°). Use of the training approach led to interrater differences that matched this after the 4th (EMD) and 3rd (aDOI) feedback/measurement series had been provided to the student.

CONCLUSIONS

The training approach enabled the student to evaluate the CI electrode position at the performance level of a senior rater. This finding may offer a basis for ongoing clinical quality assurance for the assessment of CI electrode position.

To Contrast or Not to Contrast? On the Role of Contrast Enhancement in Hand MRI Studies of Patients with Rheumatoid Arthritis

Currently, clinical indications for the application of gadolinium-based contrast agents (GBCA) in magnetic resonance imaging (MRI) are increasingly being questioned. Consequently, this study aimed to evaluate the additional diagnostic value of contrast enhancement in MRI of the hand in patients with rheumatoid arthritis (RA). Thirty-one patients with RA (mean age, 50 ± 14 years (range, 18–72 years)) underwent morphologic MRI scans on a clinical 3 T scanner. MRI studies were analyzed based on (1) the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) and (2) the GBCA-free RAMRIS version, termed RAMRIS Sine-Gadolinium-For-Experts (RAMRIS-SAFE), in which synovitis and tenosynovitis were assessed using the short-tau inversion-recovery sequence instead of the post-contrast T1-weighted sequence. The synovitis subscores in terms of Spearman’s ρ, as based on RAMRIS and RAMRIS-SAFE, were almost perfect (ρ = 0.937; p < 0.001), while the tenosynovitis subscores were less strongly correlated (ρ = 0.380 p = 0.035). Correlation between the total RAMRIS and RAMRIS-SAFE was also almost perfect (ρ = 0.976; p < 0.001). Inter-rater reliability in terms of Cohen’s κ was high (0.963 ≤ κ ≤ 0.925). In conclusion, RAMRIS-SAFE as the GBCA-free version of the well-established RAMRIS is a patient-friendly and resource-efficient alternative for assessing disease-related joint changes in RA. As patients with RA are subject to repetitive GBCA applications, non-contrast imaging protocols should be considered.

Speech comprehension across multiple CI processor generations: Scene dependent signal processing

OBJECTIVES

In clinical practice, characterization of speech comprehension for cochlear implant (CI) patients is typically administered by a set of suprathreshold measurements in quiet and in noise. This study investigates speech comprehension of the three most recent cochlear implant sound processors; CP810, CP910, and CP1000 (Cochlear Limited). To compare sound processor performance across generations and input dynamic range changes, the state-of-the art signal processing technologies available in each sound processor were enabled. Outcomes will be assessed across a range of stimulation intensities, and finally analyzed with respect to normal hearing listeners.

METHODS

In a prospective study, 20 experienced postlingually deafened CI patients who received a Nucleus CI in the ENT department of the University Hospital of SH in Kiel were recruited. Speech comprehension was measured in quiet at 40, 50, and 65 dBSPL with monosyllabic words as well as by speech reception threshold for two-digit numbers. In noise, speech reception thresholds were measured with the adaptive German matrix test with speech and noise in front.

RESULTS

We found that high levels of open-set speech comprehension are achieved at suprathreshold presentation levels in quiet. However, results at lower test levels have remained mostly unchanged for tested sound processors with default dynamic range. Expanding the lower limit of the acoustic input dynamic range yields better speech comprehension at lower presentation levels. In noise the application of ForwardFocus improves the speech reception. Overall, a continuous improvement for speech perception across three generations of CI sound processors was found.

CONCLUSIONS

Findings motivate further development of signal pre-processing, an additional focus of clinical work on lower stimulation levels, and automation of ForwardFocus.

LEVEL OF EVIDENCE

2.

[Treatment guidelines for inflammatory and malignant diseases of the thyroid gland]

Most cases of thyroiditis can be treated with antibiotics, antiphlogistics, and corticosteroids. In case of abscess caused by bacterial infection or compression of the trachea surgical therapy is required for drainage and resection. The prognosis for differentiated malignant tumours of the thyroid gland is good even if metastases have occurred. The recommended therapy includes total resection of the thyroid gland and radioiodine therapy to eliminate any remaining thyroid tissue. For anaplastic thyroid carcinomas surgery should be considered because of the extremely poor prognosis for these types of tumours. Resection should be performed to improve the patient's quality of life by avoiding tracheostoma or to ensure normal nutritional uptake. Medullary thyroid carcinoma is known in sporadic and in hereditary forms. Thyroidectomy is the accepted therapy. In 15% of the patients we observed the syndrome of multiple endocrine neoplasms (MEN), which is a form of thyroid carcinoma complicated by pheochromocytoma and hyperparathyroidism. Diagnosis of thyroid carcinomas includes examination of the patient, scintigraphy and ultrasonography of the thyroid gland, and cytological examination by aspiration biopsy. Post-operative care includes substitution of thyroid hormones, regular measurement of the thyreoglobulin levels in the blood, and examination for metastases in the lungs, the abdomen, and the bones.

Alteration of monocyte function following major injury

The macrophage exerts its stimulatory and regulatory functions within the specific immune response via the interleukin 1 (IL-1) and prostaglandin E2 (PGE2), respectively. In a screening study of macrophage-related variables following injury, a total of 58 patients (mean age, 32 years; mean injury Severity Score, 38), macrophagic phenotyping with the monoclonal antibody Leu M3 and serial measuring of the antagonistic monokines IL-1 and PGE2 and of the macrophage-activating lymphokine interferon gamma were carried out on posttrauma days 0, 1, 3, 5, 7, 10, 14, and 21. The posttraumatic course was characterized by significant monocytosis, showing a peak value of 32% of Leu M3-positive cells compared with 15% of these cells in normal control subjects. During the posttrauma course, the macrophagic PGE2 output was significantly elevated up to eightfold on days 5 and 7 compared with that of control subjects (0.441 +/- 0.14 ng/mL vs 0.052 +/- 0.01 ng/mL). Conversely, macrophagic IL-1 synthesis was significantly suppressed until day 10. Levels of interferon gamma were suppressed to a significant degree during the two-day observation period, with a trend to slow recovery at the end of week 3. These data suggest that a negative regulatory macrophagic function may be the event initiating posttraumatic immunosuppression. To restore impaired macrophagic T-helper cell interaction, cyclo-oxygenase inhibition and substitution of interferon gamma may be useful to potentiate facilitatory macrophagic function and to block inhibitory macrophagic activity.

Prostaglandin E2 (PGE2)-dependent suppression of interleukin alpha (IL-2) production in patients with major trauma

The depression of interleukin-2 synthesis represents a major dysfunction within the cascade of immunologic defects induced by mechanical and thermal trauma. This study was undertaken to elucidate the negative control mechanisms that were responsible for the deficiency of IL-2 production in polytraumatized patients. Peripheral blood mononuclear cells (PBMC's) from 29 patients (average age, 35.8 years; average ISS, 35) were separated on post-trauma days 1, 3, 5, 7, 10, 14, and 21 and cultured as untreated cells (C), cells treated with indomethacin (C + INDO), and cells depleted of adherent cells (C-AC). Cell cultures were assayed for proliferative responses to PHA, IL-2 synthesis, PGE2 production, gamma-interferon levels, and phenotyping studies. On all days post-trauma there was found a marked reduction of IL-2 production compared to controls with a highly significant nadir from day 5 to day 10 with an almost 80% inhibition of IL-2 (p less than 0.005). C + INDO cells showed increases of IL-2 synthesis over untreated cells ranging from 48% (Day 1) to 220% (Day 7). Removal of adherent cells (C-AC) did not reverse the suppression of IL-2 production. gamma-interferon levels were depressed in parallel with IL-2 levels but did not increase with C + INDO. The phenotyping of the PBMC's showed highly significant suppression of OKT3+, OKT4+, and IL-2R+ lymphocytes as well as a highly significant elevation of the monocyte (p less than 0.005) count. There was a highly significant increase of PGE2 synthesis from monocytes, due to the monocytosis and to a higher capacity of synthesis of the individual cells following trauma. PGE2 levels peaked on Day 5 and 7 post-trauma at 400% of control (p less than 0.005). These data suggest that the suppression of IL-2 synthesis post trauma is caused mainly by two factors: the excessive PGE2 output of inhibitory monocytes and inadequate function in immature and/or blocked lymphocytes. The partial restoration of IL-2 synthesis by indomethacin suggests that blockade of the cyclo-oxygenase pathway as an immunomodulating therapy may reverse some of the immunologic abnormalities in multiple trauma patients.