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BioRxiv : the Preprint Server For... Jan 2024How we move our bodies affects how we perceive sound. For instance, we can explore an environment to seek out the source of a sound and we can use head movements to...
How we move our bodies affects how we perceive sound. For instance, we can explore an environment to seek out the source of a sound and we can use head movements to compensate for hearing loss. How we do this is not well understood because many auditory experiments are designed to limit head and body movements. To study the role of movement in hearing, we developed a behavioral task called sound-seeking that rewarded mice for tracking down an ongoing sound source. Over the course of learning, mice more efficiently navigated to the sound. We then asked how auditory behavior was affected by hearing loss induced by surgical removal of the malleus from the middle ear. An innate behavior, the auditory startle response, was abolished by bilateral hearing loss and unaffected by unilateral hearing loss. Similarly, performance on the sound-seeking task drastically declined after bilateral hearing loss and did not recover. In striking contrast, mice with unilateral hearing loss were only transiently impaired on sound-seeking; over a recovery period of about a week, they regained high levels of performance, increasingly reliant on a different spatial sampling strategy. Thus, even in the face of permanent unilateral damage to the peripheral auditory system, mice recover their ability to perform a naturalistic sound-seeking task. This paradigm provides an opportunity to examine how body movement enables better hearing and resilient adaptation to sensory deprivation.
PubMed: 38260458
DOI: 10.1101/2024.01.08.574475 -
Journal of the Association For Research... Feb 2024One of the major reasons that totally implantable cochlear microphones are not readily available is the lack of good implantable microphones. An implantable microphone...
PURPOSE
One of the major reasons that totally implantable cochlear microphones are not readily available is the lack of good implantable microphones. An implantable microphone has the potential to provide a range of benefits over external microphones for cochlear implant users including the filtering ability of the outer ear, cosmetics, and usability in all situations. This paper presents results from experiments in human cadaveric ears of a piezofilm microphone concept under development as a possible component of a future implantable microphone system for use with cochlear implants. This microphone is referred to here as a drum microphone (DrumMic) that senses the robust and predictable motion of the umbo, the tip of the malleus.
METHODS
The performance was measured by five DrumMics inserted in four different human cadaveric temporal bones. Sensitivity, linearity, bandwidth, and equivalent input noise were measured during these experiments using a sound stimulus and measurement setup.
RESULTS
The sensitivity of the DrumMics was found to be tightly clustered across different microphones and ears despite differences in umbo and middle ear anatomy. The DrumMics were shown to behave linearly across a large dynamic range (46 dB SPL to 100 dB SPL) across a wide bandwidth (100 Hz to 8 kHz). The equivalent input noise (over a bandwidth of 0.1-10 kHz) of the DrumMic and amplifier referenced to the ear canal was measured to be about 54 dB SPL in the temporal bone experiment and estimated to be 46 dB SPL after accounting for the pressure gain of the outer ear.
CONCLUSION
The results demonstrate that the DrumMic behaves robustly across ears and fabrication. The equivalent input noise performance (related to the lowest level of sound measurable) was shown to approach that of commercial hearing aid microphones. To advance this demonstration of the DrumMic concept to a future prototype implantable in humans, work on encapsulation, biocompatibility, and connectorization will be required.
Topics: Humans; Ear, Middle; Cochlear Implants; Ear Canal; Cochlear Implantation; Cadaver
PubMed: 38238525
DOI: 10.1007/s10162-024-00927-4 -
European Archives of... Jun 2024Patient-to-image registration is a preliminary step required in surgical navigation based on preoperative images. Human intervention and fiducial markers hamper this...
PURPOSE
Patient-to-image registration is a preliminary step required in surgical navigation based on preoperative images. Human intervention and fiducial markers hamper this task as they are time-consuming and introduce potential errors. We aimed to develop a fully automatic 2D registration system for augmented reality in ear surgery.
METHODS
CT-scans and corresponding oto-endoscopic videos were collected from 41 patients (58 ears) undergoing ear examination (vestibular schwannoma before surgery, profound hearing loss requiring cochlear implant, suspicion of perilymphatic fistula, contralateral ears in cases of unilateral chronic otitis media). Two to four images were selected from each case. For the training phase, data from patients (75% of the dataset) and 11 cadaveric specimens were used. Tympanic membranes and malleus handles were contoured on both video images and CT-scans by expert surgeons. The algorithm used a U-Net network for detecting the contours of the tympanic membrane and the malleus on both preoperative CT-scans and endoscopic video frames. Then, contours were processed and registered through an iterative closest point algorithm. Validation was performed on 4 cases and testing on 6 cases. Registration error was measured by overlaying both images and measuring the average and Hausdorff distances.
RESULTS
The proposed registration method yielded a precision compatible with ear surgery with a 2D mean overlay error of mm for the incus and mm for the round window. The average Hausdorff distance for these 2 targets was mm and mm respectively. An outlier case with higher errors (2.3 mm and 1.5 mm average Hausdorff distance for incus and round window respectively) was observed in relation to a high discrepancy between the projection angle of the reconstructed CT-scan and the video image. The maximum duration for the overall process was 18 s.
CONCLUSIONS
A fully automatic 2D registration method based on a convolutional neural network and applied to ear surgery was developed. The method did not rely on any external fiducial markers nor human intervention for landmark recognition. The method was fast and its precision was compatible with ear surgery.
Topics: Humans; Neural Networks, Computer; Tomography, X-Ray Computed; Temporal Bone; Augmented Reality; Otoscopy; Female; Video Recording; Male; Ear Diseases; Otologic Surgical Procedures; Middle Aged; Algorithms; Surgery, Computer-Assisted; Adult; Tympanic Membrane; Malleus; Endoscopy
PubMed: 38200355
DOI: 10.1007/s00405-023-08403-0 -
The Laryngoscope Jun 2024Although previous research has indicated inner ear changes in diabetes mellitus (DM) patients, no prior study has explored the middle ear, particularly the ossicles and...
OBJECTIVES
Although previous research has indicated inner ear changes in diabetes mellitus (DM) patients, no prior study has explored the middle ear, particularly the ossicles and their joints, in DM patients. This study aimed to investigate whether type 2 DM is associated with middle ear changes, specifically affecting the ossicular chain and joints.
METHODS
This study included 47 ears from 25 patients with DM (male = 13, female = 12, age: 51.0 ± 20.5) and age- and sex-matched controls (male = 10, female = 10, age: 54.8 ± 15.9) (sex; p = 1.000, Age; p = 0.991). Otopathological evaluations of the auditory ossicles and incudomalleolar joint (IMJ) were performed using light microscopy.
RESULTS
In the IMJ of DM cases, malleus hyalinized cartilage (Malleus hC) and incus hyalinized cartilage (Incus hC) were significantly increased compared with control cases (Malleus hC; DM, 34.17 ± 9.71 μm vs. control 21.96 ± 4.16 μm, p < 0.001) (Incus hC; DM 35.11 ± 10.12 μm vs. control 22.42 ± 4.368 μm, p < 0.001). In addition, bone-line distance was significantly longer than in DM cases than control cases (DM 266.72 ± 59.11 μm vs. control 239.81 ± 35.56 μm p = 0.040). On the other hand, joint discus distance was longer in the control group than in DM cases (DM 96.84 ± 36.80 μm vs. Control 113.63 ± 23.81 μm, p = 0.001).
CONCLUSIONS
This study reveals a notable increase in the hyalinized cartilage layer and bone-line distance accompanied by reducing joint discus distance within the IMJ in DM cases. These findings suggest that DM may influence microjoints, such as the IMJ, and potentially impact auditory function.
EVIDENCE LEVEL
N/A Laryngoscope, 134:2871-2878, 2024.
Topics: Humans; Female; Male; Middle Aged; Diabetes Mellitus, Type 2; Ear Ossicles; Adult; Case-Control Studies; Aged; Ear, Middle
PubMed: 38174760
DOI: 10.1002/lary.31257 -
Journal of Visualized Experiments : JoVE Dec 2023Congenital cholesteatoma accounts for 25% of cholesteatoma cases in children. Transcanal Endoscopic Ear Surgery (TEES) is ideal for these patients because it offers a...
Congenital cholesteatoma accounts for 25% of cholesteatoma cases in children. Transcanal Endoscopic Ear Surgery (TEES) is ideal for these patients because it offers a wide endoscopic view of the middle ear and a minimally invasive approach. The two main limitations are the loss of one operative hand and a narrow external auditory canal in younger children. Here, we present the case of a 3-year-old patient with a Potsic stage III congenital cholesteatoma adherent to the incus and branches of the stapes. A robotic-assisted TEES procedure was performed, during which a robotic arm with 6 degrees of freedom held a 0°, 2.9 mm wide endoscope, enabling the surgeon to work in a narrow environment with both hands. The procedure's duration was 2 h and 9 min, including 16 min for the installation and draping of the robotic arm. After a trans-canal approach, the cholesteatoma was dissected from the ossicles using both a needle (or sickle knife) and suction to stabilize the ossicles and limit the risk of hearing trauma. The cholesteatoma was debulked to reduce its size, allowing it to be pushed under the malleus anteriorly and then separated from other adherences before removal. A tragal cartilage graft was used to reinforce the tympanic membrane.
Topics: Child, Preschool; Humans; Cholesteatoma, Middle Ear; Retrospective Studies; Robotic Surgical Procedures; Robotics; Treatment Outcome
PubMed: 38163263
DOI: 10.3791/64861 -
Laryngoscope Investigative... Dec 2023We compared the histological changes and hearing restoration during the healing of acute total tympanic membrane (TM) perforations between Sprague-Dawley (SD) rats with...
OBJECTIVE
We compared the histological changes and hearing restoration during the healing of acute total tympanic membrane (TM) perforations between Sprague-Dawley (SD) rats with and without excision of the mallear handle.
MATERIALS AND METHODS
Bilateral, acute, and total TM perforations were created in 36 male SD rats. The mallear handle was preserved in the left ear (handle-preserved ear [HPE]) and excised from the right ear (handle-excised ear [HEE]). Endoscopical examination, auditory brainstem response (ABR) thresholds, histopathological, and scanning electron microscope (SEM) analysis were performed.
RESULTS
Endoscopic photographs showed that all perforations in the 18 SD rats were closed. The mean closure times were 6.83 ± 0.85 and 8.50 ± 0.71 days in the HPE and HEE groups, respectively ( < .001). SEM images showed radial arrangement of fiber bundles in a single direction in HPEs, although normal arrangement was not achieved. In contrast, HEEs showed disorganized arrangement. At 1 month after perforation closure, the ABR thresholds at high frequencies were significantly higher in the HEE group than in the HPE group ( = .029 and = .017 for 16 and 32 kHz, respectively). Additionally, the changes in ABR threshold were significantly different at high frequencies ( = .011 and = .017 for 16 and 32 kHz, respectively) before and 1 month after perforation closure between the HPE and HEE groups, although the differences were not statistically significant at the remaining frequencies.
CONCLUSION
Although the malleus handle may not affect the closure of total perforation in SD rats, it contributes to accelerate the perforation closure by possible guide the migration of proliferative epithelial cell on the upper halves of the annulus. Additionally, resection of the malleus handle impairs high frequency hearing recovery following spontaneous closure of the TM.
PubMed: 38130269
DOI: 10.1002/lio2.1175 -
Journal of Anatomy Mar 2024The sphenomandibular ligament (SML) is considered to originate from Meckel's cartilage (MC). However, no study has examined how the os goniale contributes to SML...
Sphenomandibular ligament and degenerating Meckel's cartilage revisited: Sequential variations with temporal bone deformity for ligament attachment in near-term human fetuses.
BACKGROUND
The sphenomandibular ligament (SML) is considered to originate from Meckel's cartilage (MC). However, no study has examined how the os goniale contributes to SML development.
METHODS
Semiserial histological sections of heads from 18 near-term fetuses at 27-40 weeks of gestation were examined.
OBSERVATIONS
The os goniale and the anterior process of the malleus (AP) provided a long, bar-like membranous bone complex that passed through the petrotympanic and tympanosquamosal fissures. Notably, the AP-goniale complex is sometimes elongated inferiorly to join the SML (n = 4 specimens). Along the complex in the bone fissures, a degenerating MC was often present (n = 12). With (n = 6) or without (n = 3) the MC remnant, the tympanic bone (TYB) protruded inferomedially near the tympanosquamosal fissure, and it sometimes continued to a cartilaginous SML (n = 3). The temporal bone squamosa or petrosa provided a similar bony process approaching the SML. The middle meningeal artery often ran between the sphenoid and petrosa.
CONCLUSIONS
Most of the specimens (n = 15) exhibited a sequential change from a cartilaginous SML as a continuation of the MC remnant to the ligament after the disappearance of the cartilage. The degenerating MC appeared to cause transformation from the AP-goniale complex and/or TYB to "another ligament" that replaced the usual SML at the upper part. Near the MC remnant, a similar transformation was also suggested on the squamosa or petrosa. The sphenoid spine appeared to originate often from the sphenoid ala major but sometimes from the TYB.
Topics: Humans; Temporomandibular Joint; Ligaments, Articular; Cartilage; Fetus; Temporal Bone; Mandible
PubMed: 37988318
DOI: 10.1111/joa.13974 -
Anatomia, Histologia, Embryologia Jan 2024It is important to know the morphometry of the auditory ossicles for middle ear surgical applications. The present study aims to investigate the morphometric...
It is important to know the morphometry of the auditory ossicles for middle ear surgical applications. The present study aims to investigate the morphometric measurements of sheep auditory ossicles and the relationship between these ossicles. In this study, 100 malleus, incus and stapes of 50 Akkaraman sheep were examined using at trinocular stereo microscope and a total of 19 morphometric measurements were taken. The mean values of the morphometric measurements were obtained, and correlation analysis was performed between each part of each auditory ossicle. Similarities were found between the measurements of the lengths of the malleus, manubrium mallei and incus, and the width of the base of the stapes with morphometric measurements in human auditory ossicles. A significant positive correlation was found between the length of the malleus with the length of the manubrium mallei, between the length of the incus with the lengths of the long crus and corpus incudis, between the length of the stapes with the lengths of the rostral crus, caudal crus, caput stapedis, and the length and width of the intercrural foramen. Due to the anatomic similarities between sheep and human auditory ossicles, it was concluded that the auditory ossicles of sheep are suitable for use in the training of human ear surgery applications.
Topics: Humans; Animals; Sheep; Ear Ossicles; Ear, Middle; Incus; Stapes; Malleus
PubMed: 37985461
DOI: 10.1111/ahe.12998 -
Indian Journal of Otolaryngology and... Dec 2023The temporal bone is a complex anatomical space that houses the middle ear and its ossicles, as well as the inner ear, which includes the vestibule, cochlea, and the...
The temporal bone is a complex anatomical space that houses the middle ear and its ossicles, as well as the inner ear, which includes the vestibule, cochlea, and the semicircular canals. Henle's spine, also known as the suprameatal spine/spina suprameatica/ is found to guide the lateral wall of the mastoid antrum [J Res Med Dent Sci 8(7):420-422, Stat-Pearls Publishing, Treasure Island. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559153/]. It is found that the Henle's spine is present in 85% of the human skulls and when present, it could be used as a reliable anatomical landmark for isolating various foramina during skull base surgeries [J Laryngol Otol 119:856-861], and to assess the location of handle of malleus and subsequently the mastoid antrum, in many cases. We present here 3 cases in which tympanoplasty was planned, and the position of spine of Henle was found to be anterosuperior and so was the handle of malleus. Antrostomy was done by following the spine of Henle in all cases to establish patency and maintain ventilation in the post-operative ear. These 3 cases had a much more anteriorly placed spine. Such cases need to be reported so that it creates a paradigm shift in the way that mastoid surgeries are being done. Any variation in the positioning of the spine of henle points to variability in the position of the mastoid antrum. This is extremely important while drilling the mastoid in the correct position and also to prevent drilling over the sigmoid sinus or the dura. To conclude, an anteriorly placed spine of Henle corresponds to anteriorly placed mastoid antrum.
PubMed: 37974806
DOI: 10.1007/s12070-023-04017-4