Feasibility of 3D-printed middle ear prostheses in partial ossicular chain reconstruction.

Despite advances in prosthesis materials, operating microscopes and surgical techniques during the last 50 years, long-lasting hearing improvement remains a challenge in ossicular chain reconstruction. Failures in the reconstruction are mainly due to inadequate length or shape of the prosthesis, or defects in the surgical procedure. 3D-printed middle ear prosthesis might offer a solution to individualize treatment and obtain better results. The aim of the study was to study the possibilities and limitations of 3D-printed middle ear prostheses. Design of the 3D-printed prosthesis was inspired by a commercial titanium partial ossicular replacement prosthesis. 3D models of different lengths (1.5-3.0 mm) were created with Solidworks 2019-2021 software. The prostheses were 3D-printed with vat photopolymerization using liquid photopolymer Clear V4. Accuracy and reproducibility of 3D printing were evaluated with micro-CT imaging. The acoustical performance of the prostheses was determined in cadaver temporal bones with laser Doppler vibrometry. In this paper, we present an outline of individualized middle ear prosthesis manufacturing. 3D printing accuracy was excellent when comparing dimensions of the 3D-printed prostheses and their 3D models. Reproducibility of 3D printing was good if the diameter of the prosthesis shaft was 0.6 mm. 3D-printed partial ossicular replacement prostheses were easy to manipulate during surgery even though they were a bit stiffer and less flexible than conventional titanium prostheses. Their acoustical performance was similar to that of a commercial titanium partial ossicular replacement prosthesis. It is possible to 3D print functional individualized middle ear prostheses made of liquid photopolymer with good accuracy and reproducibility. These prostheses are currently suitable for otosurgical training. Further research is needed to explore their usability in a clinical setting. In the future, 3D printing of individualized middle ear prostheses may provide better audiological outcomes for patients.

OPTIMISING THE PARAMETERS OF COCHLEAR IMPLANT IMAGING WITH CONE-BEAM COMPUTED TOMOGRAPHY.

With computed tomography (CT), the delicate structures of the inner ear may be hard to visualise, which a cochlear implant (CI) electrode array can further complicate. The usefulness of a novel cone-beam CT device in CI recipient's inner ear imaging was evaluated and the exposure parameters were optimised to attain adequate clinical image quality at the lowest effective dose (ED). Six temporal bones were implanted with a Cochlear Slim Straight electrode array and imaged with six different imaging protocols. Contrast-to-noise ratio was calculated for each imaging protocol, and three observers evaluated independently the image quality of each imaging protocol and temporal bone. The overall image quality of the inner ear structures did not differ between the imaging protocols and the most relevant inner ear structures of CI recipient's inner ear can be visualised with a low ED. To visualise the most delicate structures in the inner ear, imaging protocols with higher radiation exposure may be required.

Hearing problems in patients with hereditary gelsolin amyloidosis.

BACKGROUND: Gelsolin amyloidosis (AGel amyloidosis) is a hereditary form of systemic amyloidosis featuring ophthalmological, neurological and cutaneous symptoms. Previous studies based mainly on patients' self-reporting have indicated that hearing impairment might also be related to the disease, considering the progressive cranial neuropathy characteristic for AGel amyloidosis. In order to deepen the knowledge of possible AGel amyloidosis-related hearing problems, a clinical study consisting of the Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire, clinical examination, automated pure-tone audiometry and a speech-in-noise test was designed. RESULTS: Of the total 46 patients included in the study, eighteen (39%) had self-reported hearing loss. The mean scores in the SSQ were 8.2, 8.3 and 8.6 for the Speech, Spatial and Qualities subscales, respectively. In audiometry, the mean pure tone average (PTA) was 17.1 (SD 12.2) and 17.1 (SD 12.3) dB HL for the right and left ears, respectively, with no difference to gender- and age-matched, otologically normal reference values. The average speech reception threshold in noise (SRT) was - 8.2 (SD 1.5) and - 8.0 (SD 1.7) dB SNR for the right and left ears, respectively, which did not differ from a control group with a comparable range in PTA thresholds. CONCLUSION: Although a significant proportion of AGel amyloidosis patients experience subjective difficulties in hearing there seems to be no peripheral or central hearing impairment at least in patients up to the age of 60 years.

Simultaneous bilateral stapes surgery after follow-up of 13 years.

BACKGROUND: Eighteen patients underwent simultaneous bilateral stapes surgery in 2003-2006. OBJECTIVES: We evaluated the long-term outcomes in this patient group, and assessed their hearing in noise and binaural hearing. MATERIAL AND METHODS: Fifteen patients returned questionnaires concerning their hearing, taste function, and balance. Thirteen patients underwent pure-tone and speech audiogram, Finnish matrix sentence test, video head impulse test, and clinical examination on average 13 years after surgery. RESULTS: We found no significant difference in air- and bone conduction pure-tone average, speech audiometry, and the air-bone gap between the 1-year and the late postoperative visits. One patient had bilaterally a partial loss of the vestibulo-ocular reflex of unknown cause. CONCLUSIONS AND SIGNIFICANCE: The hearing results 13 years after simultaneous bilateral stapes surgery remained good without any significant delayed complications. Simultaneous bilateral stapes surgery is a viable treatment option in selected patients with otosclerosis.

The efficacy of microphone directionality in improving speech recognition in noise for three commercial cochlear-implant systems.

Objectives: To investigate the effect of fixed and adaptive microphone directionality on speech reception threshold (SRT) in noise when compared to omnidirectional mode in unilateral cochlear-implant (CI) use for three different CI systems.Methods: Twenty-four CI recipients with bilateral severe-to-profound hearing loss participated in the study. Eight recipients of each CI system were enrolled, and their SRT in noise was measured when the speech and noise signals were co-located in the front to serve as a baseline. The acute effect of different microphone directionalities on SRT in noise was measured with the noise emanating at 90° in the horizontal plane from the side of the CI sound processor (S0NCI).Results: When compared to the baseline condition, the individual data revealed fairly similar patterns within each CI system. In the S0NCI condition, the average improvement in SRT in noise for fixed and adaptive directionalities over the omnidirectional mode was statistically significant and ranged from 1.2 to 6.0 dB SNR and from 3.7 to 12.7 dB SNR depending on the CI system, respectively.Discussion: Directional microphones significantly improve SRT in noise for all three CI systems. However, relatively large differences were observed in the directional microphone efficacy between CI systems.

Impact noise of prostate biopsy devices.

Objective: To analyse the impact noise generated by prostate biopsy devices.Materials and methods: In a laboratory setting, repeated impact noise was recorded at distances of 50 cm and 100 cm using five brands of device on chicken meat, an apple and an empty target. In a clinical setting, the impact noise levels of prostate biopsy devices were recorded in 40 real patient cases using three brands of device.Results: In the laboratory setting, the average SPL (sound pressure level) peak level ranged from 104.3 to 121.3 dB. The highest impact noise levels were measured with the Monopty device, ranging from 114.8 to 122.4 dB. In the clinical setting, there were no statistical differences between repeated SPL values for each specific target. Also, the noise levels were equal when the same device brand was used at 50 cm and 100 cm. The highest SPLs were recorded with the Monopty device, which ranged from 110 to 127 dB. The corresponding values for the Max-Core and Multicore were from 106 to 122.5 dB and from 108 to 116.5 dB, respectively.Conclusions: Biopsy devices generate high peak levels of impact noise. Personnel performing biopsies are advised to consider using hearing protection, even though the impact noise may not induce permanent hearing loss.

Hybrid cochlear implantation: quality of life, quality of hearing, and working performance compared to patients with conventional unilateral or bilateral cochlear implantation.

The objective of the present study is to evaluate the effect of hybrid cochlear implantation (hCI) on quality of life (QoL), quality of hearing (QoH), and working performance in adult patients, and to compare the long-term results of patients with hCI to those of patients with conventional unilateral cochlear implantation (CI), bilateral CI, and single-sided deafness (SSD) with CI. Sound localization accuracy and speech-in-noise test were also compared between these groups. Eight patients with high-frequency sensorineural hearing loss of unknown etiology were selected in the study. Patients with hCI had better long-term speech perception in noise than uni- or bilateral CI patients, but the difference was not statistically significant. The sound localization accuracy was equal in the hCI, bilateral CI, and SSD patients. QoH was statistically significantly better in bilateral CI patients than in the others. In hCI patients, residual hearing was preserved in all patients after the surgery. During the 3.6-year follow-up, the mean hearing threshold at 125-500 Hz decreased on average by 15 dB HL in the implanted ear. QoL and working performance improved significantly in all CI patients. Hearing outcomes with hCI are comparable to the results of bilateral CI or CI with SSD, but hearing in noise and sound localization are statistically significantly better than with unilateral CI. Interestingly, the impact of CI on QoL, QoH, and working performance was similar in all groups.

The development and evaluation of the Finnish digit triplet test.

OBJECTIVES: The aim of the study was to develop a reliable and easily accessible screening test for primary detection of hearing impairment. METHODS: Digits 0-9 were used to form quasirandom digit triplets. First, digit specific intelligibility functions and speech recognition thresholds (SRTs) were determined. To homogenize the test material digits with steep intelligibility function slopes were chosen and level correction up to ±2 dB were applied to the digits as needed. Evaluation measurements were performed to check for systematic differences in intelligibility between the test lists and to obtain normative reference function for normal-hearing listeners. RESULTS: The mean SRT and the final slope of the test lists were -10.8 ± 0.1 dB signal-to-noise ratio (SNR) and 21.7 ± 1.8%/dB, respectively (measurements at constant level; inter-list variability). The mean SRT and slope of the test subjects were -10.8 ± 0.5 dB SNR and 23.4 ± 5.2%/dB (measurements at constant level; inter-subject variability). The mean SRT for normal-hearing young adults for a single adaptive measurement is -9.8 ± 0.9 dB SNR. CONCLUSION: The Finnish digit triplet test is the first self-screening hearing test in the Finnish language. It was developed according to current standards, and it provides reliable and internationally comparable speech intelligibility measurements.

Single-Sided Deafness: The Effect of Cochlear Implantation on Quality of Life, Quality of Hearing, and Working Performance.

AIMS: To evaluate the effect of a cochlear implant (CI) on quality of life (QoL), quality of hearing (QoH), and working performance in patients with single-sided deafness (SSD). METHODS: Using specific questionnaires, we measured QoL, QoH, and working performance in 7 SSD patients scheduled for CI surgery of the affected ear. Sound localization and speech perception in noise were also assessed. All questionnaires and tests were performed before the CI surgery and at 6 and 12 months after CI activation. RESULTS: The QoL, QoH, sound localization, and speech perception in noise had improved statistically significantly after CI surgery. Communication with co-workers became easier, and the patients were less fatigued after the working day. CONCLUSIONS: CI clearly improves QoL, QoH, and working performance in patients with SSD.

Sequential bilateral cochlear implantation improves working performance, quality of life, and quality of hearing.

CONCLUSIONS: This prospective study shows that working performance, quality of life (QoL), and quality of hearing (QoH) are better with two compared with a single cochlear implant (CI). The impact of the second CI on the patient's QoL is as significant as the impact of the first CI. OBJECTIVES: To evaluate the benefits of sequential bilateral cochlear implantation in working, QoL, and QoH. METHODS: We studied working performance, work-related stress, QoL, and QoH with specific questionnaires in 15 patients with unilateral CI scheduled for sequential CI of another ear. Sound localization performance and speech perception in noise were measured with specific tests. All questionnaires and tests were performed before the second CI surgery and 6 and 12 months after its activation. RESULTS: Bilateral CIs increased patients' working performance and their work-related stress and fatigue decreased. Communication with co-workers was easier and patients were more active in their working environment. Sequential bilateral cochlear implantation improved QoL, QoH, sound localization, and speech perception in noise statistically significantly.