Immunohistochemical localization of CD31, CD34, and periostin in vocal fold polyps.

BACKGROUND: Long-term voice-abuse or sudden vocal fold microvascular disruption can lead to injury and subsequent repair/remodeling of the vocal fold mucosa. Periostin is known to be involved in airway remodeling and in various otolaryngological diseases. In ischemic heart disease, increased CD31 expression has been observed around cardiomyocytes during remodeling, and endothelial proliferation has been reported to occur at these sites. OBJECTIVES: We investigated the expression and the roles of CD31, CD34, and periostin in the formation of vocal fold polyps. MATERIALS AND METHODS: Fifty-seven samples of vocal fold polyps were investigate histopathologically and immunohistochemically. RESULT: Expression of CD31 and CD34 was detected in 41 (71.9%) and 53 (93.0%) samples, respectively, obtained from patients with vocal fold polyp. Expression of periostin was detected in 41 (71.9%) samples obtained from patients with vocal polyps. The vocal polyp samples could be classified into three histological subtypes. Three patterns of CD31 and CD34 expression were observed in the vocal polyp. Four patterns of periostin expression were observed in vocal polyps. An association was observed between the CD31 expression pattern and the histological subtype of vocal fold polyps. CONCLUSION AND SIGNIFICANCE: In vocal fold polyps, evaluation of vascular endothelial markers may be useful for staging.

The Factors Related to the Time for Sinus Debridement after Functional Endoscopic Sinus Surgery - A Retrospective Study.

Introduction: Post-operative care after functional endoscopic sinus surgery (FESS) is essential for managing the long-term success of chronic rhinosinusitis. Post-operative sinus debridement promotes proper wound healing, but the procedure can be accompanied by discomfort and pain. Hence, we analysed the clinical factors related to sinus debridement time after FESS. Materials and Methods: We evaluated retrospectively the clinical factors affecting the time taken for post-operative sinus debridement on the first visit after the discharge. We reviewed 101 patients who underwent FESS at our hospital by the same surgeon and extracted patient information. The time for post-operative sinus debridement at the first outpatient clinic was measured. Results: The days of putting the cotton ball in the operated nostril were negatively associated with sinus debridement time (coefficient - -16.4 ± 5.7 seconds/day, P = 0.005). In contrast, current or history of asthma, amount of bleeding during the surgery, number of opened sinuses by the operation or the number of eosinophils in resected tissues under a microscope at ×400 was not associated. Discussion: We recommend the use of a cotton ball in the nostril after FESS because it shortens the sinus debridement time. Placing cotton balls in the nostril helps to maintain a humid wound environment and reduce crusting, leading to easier sinus debridement and better wound healing.

Immunohistochemical Localization of D-ß-Aspartic Acid and Periostin in Vocal Fold Polyps.

Long-term voice abuse or sudden vocal fold microvascular disruption may lead to injury and subsequent repair/remodeling in the vocal fold mucosa. Periostin is known to be involved in airway remodeling and also in various otolaryngological diseases. D-ß-aspartic acid is the major isomer of D-aspartic acid found in elderly tissue. In this study we investigated the expression and the role of D-ß-aspartic acid and periostin in the formation of vocal fold polyps. The expression patterns of D-ß-aspartic acid and periostin in 36 surgical specimens of vocal fold polyps from 36 patients were investigated immunohistochemically. In the epithelium of vocal polyps, D-ß-aspartic acid was expressed in all cases. Expression of D-ß-aspartic acid was detected in 25 samples obtained from patients with vocal fold polyps stroma. Expression of periostin was detected in 28 samples obtained from patients with vocal fold polyps. Two patterns of D-ß-aspartic acid expression were observed in vocal fold polyps stroma: positive type and negative type. The following four patterns of periostin expression were observed in vocal fold polyps: negative type, superficial type, infiltrative type, and diffuse type. An association was observed between D-ß-aspartic acid expression patterns and periostin expression patterns. From these findings we speculate that periostin and D-ß-aspartic acid participate in certain pathological changes in vocal fold polyps, such as extracellular matrix accumulation, local fibrosis, and the formation and development of vocal fold polyps.

Clinical Factors Associated With the Outcomes of Long-Term Middle Ear Ventilation Tube Insertion in Pediatric Patients.

BACKGROUND: Ventilation tube (VT) insertion is the most common treatment for otitis media with effusion (OME). However, OME recurrence and persistent tympanic membrane (TM) perforation after VT removal are encountered in a certain percentage of such children. METHODS: This study was performed to determine the outcomes of children who underwent long-term VT insertion. A total of 326 ears from 192 patients were analyzed. The associations among the patient age, sex, history of OME, history of repeated acute otitis media, placement duration, whether the VT had been removed intentionally or spontaneously, and the outcome (persistent TM perforation or OME recurrence) were analyzed. The outcomes of multiple VT tube insertions were also reviewed. We also analyzed whether or not local or general anesthesia was associated with the early spontaneous extrusion of the VT. RESULT: The OME recurrence and TM perforation rates were 29% (96/326 sides) and 17% (57/326 sides), respectively, for first insertions. In addition, 96 (29%) sides underwent ≥2 insertions. The shorter the duration for which the VT was retained in the middle ear, the more significant the rate of increase in OME recurrence. The OME recurrence was observed more often when VT was spontaneously removed than when intentionally removed. The rate of persistent TM perforation was significantly associated with male sex. Persistent TM perforation was not observed in patients who underwent 4 or 5 insertions. The anesthesia method did not significantly influence the timing of spontaneous extrusion of VT. CONCLUSION: The retention period of VT should be at least 2 years, and VT removal at the age of 7 might be a viable strategy. Multiple VT insertions are recommended for patients with recurrent OME. Ventilation tube under local anesthesia is an effective option for tolerable children.

Clinical and Epidemiological Characteristics of Bloodstream Infections in Head and Neck Cancer Patients: A Decadal Observational Study.

This retrospective study aims to describe the clinico-epidemiological characteristics of bloodstream infections (BSIs) and the risk factors in patients with head and neck cancer (n = 227) treated at the Department of Otolaryngology, Head and Neck Surgery, Tohoku University Hospital between April 2011 and March 2021. Overall, 23.3% of blood cultures were positive. In the culture-positive group, catheter-related bloodstream infections (CRBSIs) were the most common (38.8%), followed by respiratory tract infections (19.4%), and catheter-associated urinary tract infections (6.0%). Methicillin-resistant Staphylococcus aureus (26.9%), Staphylococcus epidermidis (17.9%), and Pseudomonas aeruginosa (10.4%) infections were common. The most frequent treatment for head and neck cancer was surgery (23.9%), followed by treatment interval or palliative care (19.4%), and single radiotherapy (13.4%). The 30-day mortality rate was significantly higher in the BSI than in the non-BSI group (10.4% vs. 1.8%, respectively). CRBSIs are the most frequent source of BSIs in patients with head and neck cancer. In conclusion, central venous catheters or port insertion should be used for a short period to prevent CRBSIs. The risk of developing BSI should be considered in patients with pneumonia. Understanding the epidemiology of BSIs is crucial for diagnosing, preventing, and controlling infections in patients with head and neck cancer.

Cardiovocal Syndrome Associated With Idiopathic Pulmonary Arterial Hypertension: A Case Report and Literature Review.

Cardiovocal syndrome is left recurrent laryngeal nerve palsy associated with cardiovascular disease. Herein, we report a rare case of left recurrent laryngeal nerve palsy caused by idiopathic pulmonary arterial hypertension. A 40-year-old woman diagnosed with idiopathic pulmonary arterial hypertension was referred to our department for occult infection foci in the ear, nose, and throat (ENT). She had no apparent subjective symptoms in the ENT area, including hoarseness. Flexible laryngoscopy revealed left vocal cord paralysis, and contrast-enhanced computed tomography revealed dilatation of the pulmonary trunk, bilateral pulmonary arteries, and right ventricle, suggesting compression of the left recurrent laryngeal nerve. In our daily practice, when we encounter a left recurrent laryngeal nerve palsy that seems to be endogenous, cardiovascular lesions should be ruled out.

Expression of Periostin in Vocal Fold Polyps.

Long-term voice abuse or sudden vocal fold microvascular disruption may lead to injury and subsequent repair/remodeling in the vocal fold mucosa. Periostin is known to be involved in airway remodeling and also in various otolaryngological diseases. The aim of this article was to investigate the expression and the role of periostin in the formation of vocal fold polyps. The expression patterns of periostin in 59 surgical specimens of vocal fold polyps from 54 patients were investigated immunohistochemically. Normal vocal fold mucosa specimens from 5 patients who had undergone total laryngectomy were used as the control group. Retrospective study with planned data collection was conducted at Tohoku Medical and Pharmaceutical University. Expression of periostin was detected in 43 (72.9%) samples and four patterns of periostin expression were observed in vocal fold polyps: negative type, superficial type, infiltrative type, and diffuse type. An association was observed between periostin expression patterns and the histological subtypes of vocal fold polyps. The infiltrative pattern of periostin expression was significantly dominant in vascular-hyaline types. Expression of transforming growth factor-ß (TGF-ß) was also detected in the vocal fold polyps. Our results confirmed that periostin might be involved in certain pathological changes in vocal fold polyps, such as extracellular matrix accumulation, local fibrosis, and formation and development of vocal fold polyps.

Sinonasal Inverted Papilloma Showing a Misleading Finding on Magnetic Resonance Imaging.

Sinonasal inverted papilloma (IP) is the most common benign tumor in sinonasal cavities. Treatment involves excising the whole tumor, so it is essential to evaluate the extent of the tumor by preoperative radiographic findings. Magnetic resonance imaging (MRI) is superior to computed tomography (CT) for determining a tumor's location as MRI can discern the difference between mucus and IP. We herein report a 51-year-old man with sinonasal IP treated with endoscopic sinus surgery (ESS). Preoperative MRI showed findings resembling a convoluted cerebriform pattern on T2-weighted imaging, but this site was not enhanced by intravenous gadolinium at all. We preoperatively suspected that this site was not part of the tumor but rather the accumulation of mucus, and indeed, we found no tumor at this site when we performed the surgery. This patient is a valuable example of misleading findings of IP on T2-weighted imaging and underscores the importance of contrast-enhanced T1-weighted imaging to determine the extent of IP.

Outcome of the 'waiting until spontaneous extrusion' strategy for long-term tympanostomy tube placement in children with cleft palate.

BACKGROUND: Otitis media with effusion (OME) in children with cleft palate (CP) is known to be refractory to treatment and most of these patients undergo surgery for ventilation tube (VT) placement. OBJECTIVES: To identify the outcomes of children with CP using long-term VT with a 'waiting until spontaneous extrusion' strategy. MATERIAL AND METHODS: We retrospectively reviewed the medical records of all children with CP who visited our department from December 2016 to November 2017 and who received long-term VT placement in our department. Risk factors related to residual perforation and recurrence of OME were analyzed. RESULTS: A total of 106 children were included in this study. Our statistical analysis of 94 ears followed for more than three months after VT loss revealed that longer VT placement was associated with residual perforation, and shorter VT placement was associated with OME recurrence. Although a longer duration of VT placement was associated with an increased rate, extremely long-term VT placement was not associated with residual perforation, as expected. Half of the VTs were spontaneously extruded at 40 months after insertion. CONCLUSIONS AND SIGNIFICANCE: Long-term VT insertion using a waiting until spontaneous extrusion strategy is a potential option for children with CP.

Paranasal sinus actinomycosis treated with a combination of surgery and long-term low-dose macrolide.

Actinomycosis is a bacterial infection caused by actinomyces. Although almost 50% of cases are related to the head and neck region, those in the nose and paranasal sinuses (PNS) are rare. Actinomycosis of the PNS is presumed to be typically caused by dental caries, dental manipulation, and maxillofacial trauma, which facilitate the penetration of oral pathogens into the sinus, and should thus be treated by the combination of surgical removal and potent antibiotics for at least two months. The current use of these antibiotics might be redundant, considering the nature of actinomycosis of the PNS, which does not invade the mucosal surface. We herein report a 67-year-old female treated with endoscopic sinus surgery (ESS) and diagnosed with actinomycosis of the PNS by pathological findings. She had no history of dental impairment or treatment. She was given routine perioperative prophylactic antibiotics (cefazolin) during the surgery, followed by low-dose clarithromycin. The mucosa of the PNS normalized without any discharge by three months after the operation. The patient is a valuable example that should prompt reconsideration of the commonly accepted pathogenesis and treatment of actinomycosis of the PNS.

Chronic Maxillary Atelectasis without Obstruction of the Maxillary Ostium - A Case Report.

Rationale: Chronic maxillary atelectasis (CMA) is assumed to be caused by negative pressure in the maxillary sinus secondary to the obstruction of the ostiomeatal complex. Patient Concerns: A 49-year-old female patient first presented to our hospital complaining of right nasal congestion, rhinorrhoea and cheek pain. Diagnosis: Computed tomography (CT) accidentally revealed the inward bowing of the left maxillary sinus, which is a typical sign of CMA or silent sinus syndrome despite the maxillary ostium being potent. Treatment: We did not consider any intervention for CMA because she had no symptoms related to it. Outcomes and Take-Away Lessons: No progression was noted clinically or on CT at the 6-month follow-up. The pathogenesis of CMA in our patient was not explainable by the commonly accepted theory. Apparent hypertrophy of the left maxillary bone was confirmed on CT, thus osteitis with chronic rhinosinusitis might be the potential cause of CMA in the open maxillary sinus.

Characteristics of aspiration pneumonia patients in acute care hospitals: A multicenter, retrospective survey in Northern Japan.

BACKGROUND: Pneumonia is a common cause of illness and death of the elderly in Japan. Its prevalence is escalating globally with the aging of population. To describe the latest trends in pneumonia hospitalizations, especially aspiration pneumonia (AP) cases, we assessed the clinical records of pneumonia patients admitted to core acute care hospitals in Miyagi prefecture, Japan. METHODS: A retrospective multi-institutional joint research was conducted for hospitalized pneumonia patients aged ≥20 years from January 2019 to December 2019. Clinical data of patients were collected from the medical records of eight acute care hospitals. RESULTS: Out of the 1,800 patients included in this study, 79% of the hospitalized pneumonia patients were aged above 70 years. The most common age group was in the 80s. The ratio of AP to total pneumonia cases increased with age, and 692 out of 1,800 patients had AP. In univariate analysis, these patients had significantly older ages, lower body mass index (BMI), a lower ratio of normal diet intake and homestay before hospitalization, along with more AP recurrences and comorbidities. During hospitalization, AP patients had extended fasting periods, more swallowing assessments and interventions, longer hospitalization, and higher in-hospital mortality rate than non-AP patients. A total of 7% and 2% AP patients underwent video endoscopy and video fluorography respectively. In multivariate analysis, lower BMI, lower C-reactive protein, a lower ratio of homestay before hospitalization, a higher complication rate of cerebrovascular disease, dementia, and neuromuscular disease were noted as a characteristic of AP patients. Swallowing interventions were performed for 51% of the AP patients who had been hospitalized for more than two weeks. In univariate analysis, swallowing intervention improved in-hospital mortality. Lower AP recurrence before hospitalization and a lower ratio of homestay before hospitalization were indicated as characteristics of AP patients of the swallowing intervention group from multivariate analysis. Change in dietary pattern from normal to modified diet was observed more frequently in the swallowing intervention group. CONCLUSION: AP accounts for 38.4% of all pneumonia cases in acute care hospitals in Northern Japan. The use of swallowing evaluations and interventions, which may reduce the risk of dysphagia and may associate with lowering mortality in AP patients, is still not widespread.

First case of an invasive Bacteroides dorei infection detected in a patient with a mycotic aortic aneurysm-raising a rebellion of major indigenous bacteria in humans: a case report and review.

BACKGROUND: Bacteroides dorei is an anaerobic gram-negative bacterium first described in 2006. Because of the high similarity in mass spectra between B. dorei and Bacteroides vulgatus, discriminating between these species is arduous in clinical practice. In recent decades, 16S rRNA gene sequencing has been a complementary method for distinguishing taxonomically close bacteria, including B. dorei and B. vulgatus, at the genus and species levels. Consequently, B. dorei has been shown to contribute to some diseases, including type 1 autoimmune diabetes mellitus and atherosclerotic diseases. However, there are no reports on invasive infectious diseases caused by B. dorei. This report describes the first case of direct invasion and colonisation of human tissue by B. dorei, thus providing a warning regarding the previously proposed application of B. dorei as a live biotherapeutic for atherosclerotic diseases. CASE PRESENTATION: A 78-year-old Japanese man complained of intermittent chest/back pain and was diagnosed with a mycotic thoracic aortic aneurysm by enhanced computed tomography on admission. Despite strict blood pressure control and empirical antibiotic therapy, the patient's condition worsened. To prevent aneurysmal rupture and eliminate infectious foci, the patient underwent surgical treatment. The resected specimen was subjected to tissue culture and 16S rRNA gene sequencing analysis to identify pathogenic bacteria. A few days after the surgery, culture and sequencing results revealed that the pathogen was B. dorei/B. vulgatus and B. dorei, respectively. The patient was successfully treated with appropriate antibacterial therapy and after improvement, was transferred to another hospital for rehabilitation on postoperative day 34. There was no recurrence of infection or aneurysm after the patient transfer. CONCLUSIONS: This report describes the first case of invasive infectious disease caused by B. dorei, casting a shadow over its utilisation as a probiotic for atherosclerotic diseases.

Comparison of Magnetic Resonance Imaging and Computed Tomography in the Evaluation of the Olfactory Cleft and Ethmoidal Cells.

ABSTRACT: No study has examined whether magnetic resonance imaging (MRI) alone can be used for evaluating olfactory cleft and ethmoidal sinus in patients with olfactory disorders. Therefore, we analyzed the discrepancies between computed tomography (CT) and MRI in the imaging of the olfactory cleft and ethmoidal sinus. Patients who underwent CT and MRI within 30 days were evaluated. Age, sex, diagnosis, presence of bronchial asthma (BA), peripheral blood eosinophil percentage, and CT and MRI findings were retrospectively reviewed, and the sinuses were assessed on a scale of 0 to 3. Overall, 146 patients with 292 sinuses were enrolled. The ethmoid sinus score and the olfactory cleft score had 77.1% and 72.6% image similarity in CT and MRI. Sex and BA status were not associated with olfactory cleft score discrepancies (sex: P = 0.52, BA: P = 0.41). Magnetic resonance imaging scores tended to be rated higher than the CT scores as age increased, although this difference was not statistically significant (P = 0.09). The higher the peripheral blood eosinophil percentage, the more the magnitude by which the CT score tended to exceed the MRI score; however, this finding was also not statistically significant (P = 0.11). Magnetic resonance imaging scans should be limited to the evaluation of intracranial regions. Scans of olfactory cleft and ethmoid cells are not accurate for the assessment of olfactory dysfunction.

Prevalence of Helicobacter pylori among residents and their environments in the Nara prefecture, Japan.

BACKGROUND: Chronic infection with Helicobacter pylori, specifically cagA-positive strains, is associated with gastric cancer. Thus, measures to prevent H. pylori infection are required. This study was conducted to clarify the prevalence of H. pylori in the community to identify the infection source and comprehensively assess the risk of H. pylori infection. METHODS: We collected 90 human faecal samples and 73 environmental samples (water, vegetable, and animal faecal samples) from the residents in an area with a high incidence of gastric cancer in Japan. Polymerase chain reaction assay was performed to detect the glmM housekeeping gene and the cagA virulence gene of H. pylori. A questionnaire survey was conducted, and the responses were analyzed statistically. RESULTS: The glmM gene was detected in 18 of 90 (20%) faecal samples obtained from residents; among them, the cagA gene was detected in 33.3% (6/18), and in all who had undergone eradication therapy. H. pylori was not detected in environmental samples. However, contact with dogs (OR 3.89, 95% CI 1.15-13.15, P < 0.05) was associated with higher odds for glmM gene positivity in the questionnaire survey. CONCLUSIONS: The prevalence of H. pylori and cagA-positive strains among the residents was low. However, the study results suggest a correlation between recurrent infection and cagA-positive H. pylori strains. Although H. pylori genes were not detected in living environments, an association between contact with dogs and a glmM positive status was revealed. Further investigations targeting community-dwelling healthy people and their living environments would be required for H. pylori infection control.

A global phylogenetic analysis of Japanese tonsil-derived Epstein-Barr virus strains using viral whole-genome cloning and long-read sequencing.

Epstein-Barr virus (EBV) establishes lifelong latent infection in the majority of healthy individuals, while it is a causative agent for various diseases, including some malignancies. Recent high-throughput sequencing results indicate that there are substantial levels of viral genome heterogeneity among different EBV strains. However, the extent of EBV strain variation among asymptomatically infected individuals remains elusive. Here, we present a streamlined experimental strategy to clone and sequence EBV genomes derived from human tonsillar tissues, which are the reservoirs of asymptomatic EBV infection. Complete EBV genome sequences, including those of repetitive regions, were determined for seven tonsil-derived EBV strains. Phylogenetic analyses based on the whole viral genome sequences of worldwide non-tumour-derived EBV strains revealed that Asian EBV strains could be divided into several distinct subgroups. EBV strains derived from nasopharyngeal carcinoma-endemic areas constitute different subgroups from a subgroup of EBV strains from non-endemic areas, including Japan. The results could be consistent with biased regional distribution of EBV-associated diseases depending on the different EBV strains colonizing different regions in Asian countries.

Genomic characteristics of listeria monocytogenes causing invasive listeriosis in Japan.

We reviewed 18 listeriosis cases in Japan and performed molecular analysis of causative Listeria monocytogenes (LM) isolates. Strains genetically related to those from other countries caused various types of listeriosis, including vascular listeriosis in immunocompetent elderly people. Our results highlight the importance of integrated clinical and genomic analysis of LM.

Molecular characteristics of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae in Japan: Predominance of CTX-M-15 and emergence of hypervirulent clones.

OBJECTIVE: To provide data on the molecular characteristics of extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae clinical isolates in Japan. METHODS: A total of 100 clinical isolates of ESBL-producing K. pneumoniae collected throughout Japan between June and July 2018 were studied. ESBL genes were analyzed using PCR and DNA sequencing. Transferability of ESBL genes was investigated by conjugation experiments. Plasmid replicon types, virulence genes (rmpA, rmpA2, iucA, iroB, and peg-344) associated with hypervirulent K. pneumoniae (hvKp), and capsule types were detected using PCR. Genotyping was performed using multilocus sequence typing. RESULTS: All ESBL-producing isolates carried blaCTX-M genes. The most predominant CTX-M-type identified was CTX-M-15 (n=55). We identified 24 sequence types (STs) among the CTX-M-15 producers, with ST25 (n=8) being the most common. Most of the transconjugants carrying blaCTX-M-15 contained the FIIk replicon. Of the 100 ESBL-producing isolates, 31 were hvKp defined by the presence of the virulence genes. These ESBL-producing hvKp isolates belonged to eight STs (STs 23, 25, 36, 65, 86, 268, 412, and 4492), with five capsule types (K1, K2, K20, K57, and undefined). CONCLUSIONS: CTX-M-15 was the predominant ESBL among K. pneumoniae isolates from Japan. This study shows that ESBL-producing hvKp strains comprising various clones are emerging in Japan.

Longitudinal changes in dynamic characteristics of neonatal external and middle ears.

OBJECTIVES: Neonates have smaller and less mature ears than adults. Developmental changes in structure and function continually occur after birth and may affect the diagnostic results obtained by audiometric assessment instrumentation, such as tympanometry and otoacoustic emission. In the present study, we investigated longitudinal changes in external and middle ear dynamic characteristics by performing sweep frequency impedance (SFI) tests. METHODS: SFI tests were longitudinally performed on healthy Japanese neonates (1 female and 1 male) from birth to 3 and 5 months, respectively. A sound of sweeping sinusoidal frequency, ranging from 0.1 kHz to 2 kHz, was presented to the ear canal at 50-daPa intervals of static pressure from +200 to -200 daPa. Test results were expressed a curve showing the sound pressure level (SPL) relative to probe tone frequency, called SPL curve. RESULTS: The first fluctuation in resonance frequency (RF1) and SPL (ΔSPL1), related to the external ear, showed significant developmental changes as chronological age increased; that is, RF1 and ΔSPL1 were respectively increased and decreased and thereafter became unmeasurable by 5 months of age. In contrast, the second fluctuation in resonance frequency (RF2) and SPL (ΔSPL2), related to the middle ear, did not show significant changes over the measurement period. CONCLUSIONS: The present results suggest that the dynamic characteristics of the external ear canal wall changed with increases in chronological age; the resonance of the wall at about 0.3 kHz at birth tended to increase to about 0.7 kHz and to be unmeasurable by 5 months of age, while those of the middle ear did not significantly changed. These results showing how neonatal-ear dynamics changes with chronological age may be an important key in further hearing research and the development of hearing devices and diagnostic tools suitable for neonates.