The anatomy of the auditory region of fossil hominins may shed light on the emergence of human spoken language. Humans differ from other great apes in several features of the external, middle and ...inner ear (e.g., short external ear canal, small tympanic membrane, large oval window). However, the functional implications of these differences remain poorly understood as comparative audiometric data from great apes are scarce and conflicting. Here, we measure the sound transfer function of the external and middle ears of humans, chimpanzees and bonobos, using laser-Doppler vibrometry and finite element analysis. This sound transfer function affects auditory thresholds, which relate to speech reception thresholds in humans. Unexpectedly we find that external and middle ears of chimpanzees and bonobos transfer sound better than human ones in the frequency range of spoken language. Our results suggest that auditory thresholds of the last common ancestor of Homo and Pan were already compatible with speech reception as observed in humans. Therefore, it seems unlikely that the morphological evolution observed in the bony auditory region of fossil hominins was driven by the emergence of spoken language. Instead, the peculiar human configuration may be a by-product of morpho-functional constraints linked to brain expansion.
One factor for the lacking integration of the middle ear stapes footplate prosthesis or the missing healing of stapes footplate fractures could be the known osteogenic inactivity. In contrast, it was ...recently demonstrated that titanium prostheses with an applied collagen matrix and immobilised growth factors stimulate osteoblastic activation and differentiation on the stapes footplate. Regarding those findings, the aim of this study was to evaluate the potential of bone regeneration including bone remodeling in the middle ear. Ten one-year-old female merino sheep underwent a middle ear surgery without implantation of middle ear prostheses or any other component for activating bone formation. Post-operatively, four fluorochromes (tetracycline, alizarin complexion, calcein green and xylenol orange) were administered by subcutaneous injection at different time points after surgery (1 day: tetracycline, 7 days: alizarin, 14 days: calcein, 28 days: xylenol). After 12 weeks, the temporal bones including the lateral skull base were extracted and histologically analyzed. Fluorescence microscopy analysis of the entire stapes with the oval niche, but in particular stapes footplate and the Crura stapedis revealed evidence of new bone formation. Calcein was detected in all and xylenol in 60% of the animals. In contrast, tetracycline and alizarin could only be verified in two animals. The authors were able to demonstrate the osseoregenerative potential of the middle ear, in particular of the stapes footplate, using fluorescence sequence labelling.
For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ...ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard. With the current study, we investigate the influence of inner ear impedance in more detail and find possible reasons for deviations in the previous studies.
11 fresh frozen temporal bones were prepared in our study. The factors related to inner ear impedance, including round window membrane stiffness, cochleostomy, cochlea fluid and cochlea destruction were involved in the experimental design. After measuring in the intact specimen as a reference (step 1), the round window membrane was punctured (step 2), then completely removed (step 3). The cochleostomy was performed (step 4) before the cochlear fluid was carefully suctioned through scala tympani (step 5) and scala vestibuli (step 6). Finally, cochlea was destroyed by drilling (step 7). Translational and rotational movement of the stapes footplate were measured and calculated at each step. The results of the steps were compared to quantify the effect of inner ear impedance changing related to the process of cochlear drainage.
As the inner ear impedance decreases from step 1 to 7, the amplitudes of the METF curves at each frequency gradually increase in general. From step 6 on, the measured METF are significantly different with respect to the intact group at high frequencies above 3 kHz. The differences are frequency dependent. However, the significant decrement of rotational motion appears at the frequencies above 4.5 kHz from the step 5.
This study confirms the influence of inner ear impedance on METF only at higher frequencies (≥3 kHz). The rotational motions are more sensitive to the drainage of fluid at the higher frequency. Study results that found no influence of cochlea impedance may be due to incomplete drainage of the cochlea.
•The influence of inner ear impedance on METF occurs only at higher frequencies (≥3 kHz).•Debates about the influence of cochlea impedance on METF may be due to incomplete drainage of the cochlea.•Rotational motions of SFP are more sensitive to the fluid drainage at the higher frequency than translational motions.•We found no statistically significant effect of round window stiffness or cochleostomy on the METF.•Single point method is reliable enough to represent the movement of SFP relative to three points method.
the word recognition score (WRS) achieved with cochlear implants (CIs) varies widely. To account for this, a predictive model was developed based on patients' age and their pre-operative WRS. This ...retrospective study aimed to find out whether the insertion depth of the nucleus lateral-wall electrode arrays contributes to the deviation of the CI-achieved WRS from the predicted WRS.
patients with a pre-operative maximum WRS > 0 or a pure-tone audiogram ≥80 dB were included. The insertion depth was determined via digital volume tomography.
fifty-three patients met the inclusion criteria. The median WRS achieved with the CI was 70%. The comparison of pre- and post-operative scores achieved with a hearing aid and a CI respectively in the aided condition showed a median improvement of 65 percentage points (pp). A total of 90% of the patients improved by at least 20 pp. The majority of patients reached or exceeded the prediction, with a median absolute error of 11 pp. No significant correlation was found between the deviation from the predicted WRS and the insertion depth.
our data support a previously published model for the prediction of the WRS after cochlear implantation. For the lateral-wall electrode arrays evaluated, the insertion depth did not influence the WRS with a CI.
The objective of this study was to assess hearing outcome after sequential cholesteatoma surgery stratified for exclusively transcanal technique (ETC), combined transcanal and transmastoidal ...technique (TCM) and canal wall down surgery (CWD) and to analyze the impact of ossicular reconstruction technique (partial ossicular replacement prostheses/PORP and total ossicular replacement prostheses/TORP) on hearing outcome. This study is a retrospective case review and clinical case study conducted in a tertiary referral center. Patients who underwent 376 cholesteatoma surgeries (2007–2009) and 92 ears in clinical re-examination at least 12 months postoperatively were included. Sequential cholesteatoma surgery with ETC, TCM, or CWD; ossiculoplasty with PORP or TORP were the interventions administered. Pre- and postoperative air–bone gap (ABG) and air conduction threshold (AC) for 0.5–3 kHz were the main outcome measures. Overall, the mean preoperative ABG decreased from 25.3 ± 1.3 to 19.8 ± 0.9 dB with a mean ABG closure of 5.4 ± 1.3 dB (
p
≤ 0.001). According to surgical technique, the postoperative ABG after CWD 23.5 ± 2.1 was significantly worse compared to ETC (17.3 ± 1.0 dB,
p
< 0.05) and TCM (19.4 ± 1.3 dB). A significant ABG closure was observed after ETC (6.8 ± 2.0 dB,
p
< 0.01) and TCM (6.5 ± 2.0 dB,
p
< 0.01) contrary to CWD (2.1 ± 2.9 dB,
p
> 0.05). Patients receiving PORP showed a significantly less ABG postoperatively (19.0 ± 0.9 dB,
p
≤ 0.05) compared to the TORP group (24.1 ± 2.5 dB). However, a significant hearing gain was assessed after PORP- (4.7 ± 1.6 dB,
p
≤ 0.01) and TORP- implantation (10.4 ± 3.7 dB,
p
≤ 0.01). Sequential cholesteatoma surgery allowed for an excellent hearing outcome postoperatively. An intact posterior canal wall and a present stapes suprastructure were identified to predict a significantly superior hearing result. In addition to the technical and prosthetic considerations, the audiological outcome was confounded by the attending middle ear pathology.
Endoscopic optical coherence tomography (OCT) offers a non-invasive approach to perform the morphological and functional assessment of the middle ear in vivo. However, interpreting such OCT images is ...challenging and time-consuming due to the shadowing of preceding structures. Deep neural networks have emerged as a promising tool to enhance this process in multiple aspects, including segmentation, classification, and registration. Nevertheless, the scarcity of annotated datasets of OCT middle ear images poses a significant hurdle to the performance of neural networks. We introduce the Dresden in vivo OCT Dataset of the Middle Ear (DIOME) featuring 43 OCT volumes from both healthy and pathological middle ears of 29 subjects. DIOME provides semantic segmentations of five crucial anatomical structures (tympanic membrane, malleus, incus, stapes and promontory), and sparse landmarks delineating the salient features of the structures. The availability of these data facilitates the training and evaluation of algorithms regarding various analysis tasks with middle ear OCT images, e.g. diagnostics.
Sound transfer of active middle ear implants Beleites, Thomas; Neudert, Marcus; Bornitz, Matthias ...
Otolaryngologic clinics of North America,
12/2014, Letnik:
47, Številka:
6
Journal Article
Recenzirano
Implantable hearing aids are gaining importance for the treatment of sensorineural hearing loss and also for mixed hearing loss. The various hearing aid systems, combined with different middle ear ...situations, give rise to a wide range of different reconstructions. This article attempts to summarize the current knowledge concerning the mechanical interaction between active middle ear implants (AMEIs) and the normal or reconstructed middle ear. Some basic characteristics of the different AMEIs are provided in conjunction with the middle ear mechanics. The interaction of AMEIs and middle ear and the influence of various boundary conditions are discussed in more detail.
