Mycobiome of the external ear canal of healthy cows.

Malassezia yeasts belong to the normal skin microbiota of a wide range of warm-blooded animals. However, their significance in cattle is still poorly understood. In the present study, the mycobiota of the external ear canal of 20 healthy dairy Holstein cows was assessed by cytology, culture, PCR, and next-generation sequencing. The presence of Malassezia was detected in 15 cows by cytology and PCR. The metagenomic analysis revealed that Ascomycota was the predominant phylum but M. pachydermatis the main species. The Malassezia phylotype 131 was detected in low abundance. Nor M. nana nor M. equina were detected in the samples.

The mycobiota of the external ear canal of healthy cows was assessed by cytology, culture, PCR, and NGS. The presence of Malassezia was detected by cytology and PCR. Ascomycota was the main phylum and M. pachydermatis the main species. The Malassezia phylotype 131 was also detected in the samples.

[A case of trichoblastoma of the auricular cavity and review of the literature].

Trichoblastoma（TB） is a rare germ cell skin adnexal tumor of the hair, and it is a rare follicular tumor of the skin that differentiates from the hair germ epithelium and is often regarded as a benign skin tumorHowever, it is poorly confined and has a local infiltrative growth pattern. tb occurs in the head and neck region, especially in the face, and presents clinically as a slow growing, well-defined and elevated nodule. TB is routinely treated surgically. Due to the lack of universally accepted treatment guidelines or protocols, the recurrence rate after surgery is high, which makes clinical cure more difficult. In this study, a 65-year-old female patient was found to have a swelling with recurrent rupture and pus flow from the right external auditory canal opening and the auricular cavity. After initial misdiagnosis as otitis externa, she was treated with conventional anti-infective therapy, but her symptoms did not resolve and gradually worsened before coming to our hospital. The condition presented in this case is relativelyrare,therepre,timely and accurate diagnosis and treatment are crucial for prognosis improvement of such diseases.

Effects of no perforation margin trimming and EAC packing in cartilage underlay myringoplasty for chronic large perforations in children.

OBJECTIVE: Trimming of perforation margins and external auditory canal (EAC) packing are basic procedures in underlay myringoplasty for repairing chronic perforations. The objective of this study was to compare the operation time, graft outcome, hearing improvement, and complications of endoscopic cartilage underlay myringoplasty with and without trimming of perforation margins and EAC packing in children. STUDY DESIGN: Prospective, randomized study. SETTING: Tertiary referral center. MATERIAL AND METHODS: Pediatric patients older than 12 years with chronic perforations were randomly divided into two groups: myringoplasty with trimming of perforation margin and EAC packing (TPME) group or no trimming of perforation margin and EAC packing (NTPME) group. The operation time, graft success rate, hearing improvement, and complications were compared between the two groups. RESULTS: Fifty-two patients were ultimately included in the study. The mean operation time was 31.4 ± 4.2 min in the TPME group and 23.6 ± 1.7 min in the NTPME group; the difference was significant (P < 0.01). The rate of aural fullness significantly differed between the TPME and NTPME groups (P = 0.000). All participants were followed up for 12 months; the graft success rate did not significantly differ between the groups (88.5% vs. 96.2%; P = 0.603). No patients developed adhesive otitis media. Between the preoperative and postoperative measurements, the mean air-bone gap improved by 10.2 ± 2.8 dB in the TPME group and 11.6 ± 0.7 dB in the NTPME group; this was significant (P < 0.001) in both groups. CONCLUSIONS: Endoscopic cartilage underlay myringoplasty NTPME shorted the operation time and avoided aural fullness and EAC discomfort compared with the TPME technique; however, graft success and hearing improvement were comparable between the two techniques for repairing large perforations in children.

The influence of tympanic-membrane orientation on acoustic ear-canal quantities: A finite-element analysis.

Assuming plane waves, ear-canal acoustic quantities, collectively known as wideband acoustic immittance (WAI), are frequently used in research and in the clinic to assess the conductive status of the middle ear. Secondary applications include compensating for the ear-canal acoustics when delivering stimuli to the ear and measuring otoacoustic emissions. However, the ear canal is inherently non-uniform and terminated at an oblique angle by the conical-shaped tympanic membrane (TM), thus potentially confounding the ability of WAI quantities in characterizing the middle-ear status. This paper studies the isolated possible confounding effects of TM orientation and shape on characterizing the middle ear using WAI in human ears. That is, the non-uniform geometry of the ear canal is not considered except for that resulting from the TM orientation and shape. This is achieved using finite-element models of uniform ear canals terminated by both lumped-element and finite-element middle-ear models. In addition, the effects on stimulation and reverse-transmission quantities are investigated, including the physical significance of quantities seeking to approximate the sound pressure at the TM. The results show a relatively small effect of the TM orientation on WAI quantities, except for a distinct delay above 10 kHz, further affecting some stimulation and reverse-transmission quantities.

Outcomes of Soft Versus Bony Canal Wall Reconstruction with Mastoid Obliteration.

OBJECTIVE: To compare recidivism rates, audiometric outcomes, and postoperative complication rates between soft-wall canal wall reconstruction (S-CWR) versus bony-wall CWR (B-CWR) with mastoid obliteration (MO) in patients with cholesteatoma. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary neurotologic referral center. PATIENTS: Ninety patients aged ≥18 years old who underwent CWR with MO, either S-CWR or B-CWR, for cholesteatoma with one surgeon from January 2011 to January 2022. Patients were followed postoperatively for at least 12 months with or without second-look ossiculoplasty. INTERVENTIONS: Tympanomastoidectomy with CWR (soft vs. bony material) and mastoid obliteration. MAIN OUTCOME MEASURES: Recidivism rates; conversion rate to CWD; pre- versus postoperative pure tone averages, speech reception thresholds, word recognition scores, and air-bone gaps; postoperative complication rates. RESULTS: Middle ear and mastoid cholesteatoma recidivism rates were not significantly different between B-CWR (17.3%) and S-CWR (18.4%, p = 0.71). There was no significant difference in pre- versus postoperative change in ABG (B-CWR, -2.1 dB; S-CWR, +1.6 dB; p = 0.91) nor in the proportion of postoperative ABGs <20 dB (B-CWR, 41.3%; S-CWR, 30.7%; p = 0.42) between B-CWR and S-CWR. Further, there were no significant differences in complication rates between B-CWR and S-CWR other than increased minor TM perforations/retractions in B-CWR (63% vs. 40%, p = 0.03). CONCLUSIONS: Analysis of recidivism rates, audiometric outcomes and postoperative complications between B-CWR with MO versus S-CWR with MO revealed no significant difference. Both approaches are as effective in eradicating cholesteatoma while preserving relatively normal EAC anatomy and hearing. Surgeon preference and technical skill level may guide the surgeon's choice in approach.

Classification, registration and segmentation of ear canal impressions using convolutional neural networks.

Today, fitting bespoke hearing aids involves injecting silicone into patients' ears to produce ear canal molds. These are subsequently 3D scanned to create digital ear canal impressions. However, before digital impressions can be used they require a substantial amount of effort in manual 3D editing. In this article, we present computational methods to pre-process ear canal impressions. The aim is to create automation tools to assist the hearing aid design, manufacturing and fitting processes as well as normalizing anatomical data to assist the study of the outer ear canal's morphology. The methods include classifying the handedness of the impression into left and right ear types, orienting the geometries onto the same coordinate system sense, and removing extraneous artifacts introduced by the silicone mold. We investigate the use of convolutional neural networks for performing these semantic tasks and evaluate their accuracy using a dataset of 3000 ear canal impressions. The neural networks proved highly effective at performing these tasks with 95.8% adjusted accuracy in classification, 92.3% within 20° angular error in registration and 93.4% intersection over union in segmentation.

Epidemiology and risk factors for extension of necrotizing otitis externa.

PURPOSE: Necrotizing otitis externa (OEN) is an aggressive and morbid infection of the external acoustic meatus. What are the risk factors for OEN extension? METHODS: French monocentric retrospective study (2004-2021), including patients with OEN defined by the association of an inflamed EAM, a positive nuclear imaging, the presence of a bacteriological sample and the failure of a well-followed local and/or general antibiotic treatment. OEN was extensive if it was associated with vascular or neurological deficits, if nuclear imaging fixation and/or bone lysis extended beyond the tympanic bone. RESULTS: Our population (n = 39) was male (74%), type 2 diabetic (72%), aged 75.2 years and pseudomonas aeruginosa was found in 88% of cases. Complications for 43% of patients were extensive fixation on nuclear imaging, for 21% of them the presence of extensive bone lysis, for 13% the appearance of facial palsy, for 5.3% the presence hypoglossal nerve palsy and for 2.5% the presence of thrombophlebitis or other nerves palsies. 59% of our population had extensive OEN. The diagnosis of the extensive OEN was made 22 days later (p = 0.04). The clinical presentation was falsely reassuring due to easier identification of the tympanic membrane (70% vs 46%, p = 0.17) but associated with periauricular oedema (42% vs 0%), bone exposure (16% vs 0%) and a temporomandibular joint pain (41% vs 12%). CONCLUSION: Delayed treatment of OEN, identification of clinical bone lysis, especially when the tympanic membrane is easily visualized, and the presence of unbalanced diabetes are potential risk factors for extension of OEN.

Surgical Option for External Auditory Canal Cholesteatoma: A Case Report.

External Auditory Canal Cholesteatomas (EACC), is an exceptionally rare condition with a prevalence of only 0.1-0.5% among new patients1. EACC are known to possess bone eroding properties, causing a variety of complications, similar to the better-known attic cholesteatomas. We describe here the novel surgical management of a case of EACC. She is 38-year-old female who presented with otorrhea for 6 months. Clinical examination and radiological investigations suggested the diagnosis of an external auditory canal cholesteatoma. The patient underwent modified radical mastoidectomy with type 1 tympanoplasty with meatoplasty. Post-operatively, the patient showed marked clinical improvement.

External auditory canal reconstruction using a novel mastoidoplasty technique during canal wall down mastoidectomy: how I do it.

BACKGROUND: While mastoid obliteration techniques have received much attention in decreasing the disadvantages associated with the resultant mastoid cavity from canal wall down procedures, techniques for an anatomically normal looking ear canal reconstruction to increase the feasibility of hearing aid fitting are less commonly discussed as an alternative. METHODS: Our mastoidoplasty technique basically utilises an inferiorly based periosteal flap with or without temporalis muscles and fascia to obliterate the epitympanum and reconstruct the external auditory canal (EAC). Stay sutures are used to keep them in place. For larger cavities, demineralized bone matrix (DBM) is used to obliterate the mastoid cavity and support the neo-EAC. CONCLUSIONS: The concept of our mastoidoplasty potentially provides a very useful alternative in recreating a near normal ear canal anatomy avoiding cavity problems as well as facilitating hearing aid fitting with canal type hearing aids after canal wall down mastoidectomy.

Chronic otorrhea and osteomyelitis of the external auditory canal by Achromobacter xylosoxidans: an uncommon diagnosis.

PURPOSE: Achromobacter xylosoxidans is an emerging pathogen mainly associated with resistant nosocomial infections. This bacteria had been isolated in the ear together with other pathogens in cultures from patients with chronic otitis media, but it had never been reported as a cause of osteomyelitis of the external auditory canal. CASE PRESENTATION: We present a unique case of a healthy 81-year-old woman who presented with left chronic otorrhea refractory to topical and oral antibiotic treatment. Otomicroscopy revealed an erythematous and exudative external auditory canal (EAC) with scant otorrhea. The tympanic membrane was intact, but an area of bone remodeling with a small cavity anterior and inferior to the bony tympanic frame was observed. Otic culture isolated multi-drug-resistant A. xylosoxidans, only sensitive to meropenem and cotrimoxazole. Temporal bone computed tomography showed an excavation of the floor of the EAC compatible with osteomyelitis. Targeted antibiotherapy for 12 weeks was conducted, with subsequent resolution of symptoms and no progression of the bone erosion. CONCLUSIONS: Atypical pathogens such as A. xylosoxidans can be the cause of chronic otitis externa. Early diagnosis and specific antibiotherapy can prevent the development of further complications, such as osteomyelitis. In these cases, otic cultures play an essential role to identify the causal germ. This is the first case of EAC osteomyelitis due to A. xylosoxidans reported to date.

Expression of EGFR and p16 in Squamous Cell Carcinoma of External Auditory Canal.

The expression of EGFR and p16 in the external auditory canal squamous cell carcinoma (EACSCC) and their impacts on oncological outcomes were not well studied. Seventeen-one consecutive patients who were treated for EACSCC at Kobe University Hospital from 1995 to 2018 were enrolled in this study. The expression of EGFR, and p16 were evaluated and their impacts on oncological outcomes were statistically analyzed. Positive expression of EGFR was observed in 62 patients (87%). Strong positive expression of p16 were observed in 18 patients (32.4%), and weakly positive expression in 30 patients (42.3%), respectively. While the number of the patients with negative EGFR expression were limited, all the surgically treated patients with negative EGFR expression have been alive without disease. In the patients with T3 & T4a EACSCC, prognosis of the patients with positive p16 expression EACSCC tended to be better than those with negative p16 expression. These results suggest the clinical significance of EGFR and p16 expressions in the patients with advanced EACSCC to predict oncological outcomes.

Fungal Otitis Externa (Otomycosis) Associated with Aspergillus Flavus: A Case Image.

A 48-year-old man presented with a chief complaint of intermittent right ear otorrhea of several-month duration, occasional otalgia and progressive unilateral hearing impairment. He also reported frequent episodes of headache and pressure in the sinuses and maxilla. Previous systemic treatment with antibiotics failed to alleviate the symptoms. A head/neck CT showed completely normal mastoid, middle ear and external auditory canal regions without any evidence of opacification or bone erosion. Otoscopic examination of the right ear disclosed aggregates of dried, brown, fibrillar material and debris occluding the external auditory canal and obstructing the otherwise intact tympanic membrane. Dilation of the external auditory canal or thickening of the tympanic membrane were not appreciated. The canal was debrided and the fibrillar material was placed in formalin. Histopathologic examination revealed numerous branching, septated fungal hyphae organized in densely-packed clusters. In other areas, the fungal hyphae abutted or were attached to lamellated collections of orthokeratin. As highlighted by GMS staining, the fungi were morphologically compatible with Aspergillus species. The clinicopathologic findings supported a diagnosis of fungal otitis externa, while the numerous anucleate squamous cells were compatible with colonization of an underlying, probably developing, cholesteatoma. Culture of material isolated from the external auditory canal confirmed the presence of Aspergillus flavus. In this illustrative case, we present the main clinical and microscopic characteristics of Aspergillus-related otomycosis developing in the setting of a tautochronous cholesteatoma.

Carcinomas of the external auditory canal: Management and results: A multicenter REFCOR propensity score matching study.

OBJECTIVES: To analyse prognostic factors and survival outcomes of malignant tumors of the external auditory canal, to investigate the role of regional surgery, and adjuvant radiotherapy in early stages and to investigate the role of surgery in operable T4 stage. SETTING: A retrospective analysis was conducted on all patients prospectively included in the national database of the French Expertize Network for Rare ENT Cancers (REFCOR) from January 2000 to December 2016. PARTICIPANTS: 103 patients from 19 reference centers were included. A propensity score matching analysis was applied to enable comparisons between treatments. MAIN OUTCOMES AND MEASURES: Event-free survival, overall survival and factors of poor prognosis of the cohort were described. The interest of local and regional surgery and postoperative radiotherapy were evaluated. RESULTS: The factors of poor prognosis on event-free survival were immunosuppression (p = 0.002), Karnofsky status less than 90% (p = 0.02), body mass index less than 19 Kg / m2 (p = 0.0009), peripheric facial palsy (p = 0.0016), and positive margin (p = 0.0006). In early stages, locoregional surgery was associated with an increase in event-free survival (p = 0.003, HR = 0.21) versus local surgery alone, while postoperative radiotherapy was not associated with an increase in event-free survival (p = 0.86, HR = 0.91) or overall (p = 0.86, HR = 0.91). In locally advanced stages, locoregional surgery followed by radiotherapy was associated with an increase in event-free survival (p = 0.03, HR = 0.39) and overall (p = 0.02, HR = 0.34) versus chemoradiotherapy alone. CONCLUSION AND RELEVANCE: Regional surgery is recommended for early stages of cancers of the external auditory canal. In operable cases, locoregional surgery followed by radiotherapy is recommended.

Asymmetry in Cortical Thickness of the Heschl's Gyrus in Unilateral Ear Canal Atresia.

HYPOTHESIS: Unilateral congenital conductive hearing impairment in ear canal atresia leads to atrophy of the gray matter of the contralateral primary auditory cortex or changes in asymmetry pattern if left untreated in childhood. BACKGROUND: Unilateral ear canal atresia with associated severe conductive hearing loss results in deteriorated sound localization and difficulties in understanding of speech in a noisy environment. Cortical atrophy in the Heschl's gyrus has been reported in acquired sensorineural hearing loss but has not been studied in unilateral conductive hearing loss. METHODS: We obtained T1w and T2w FLAIR MRI data from 17 subjects with unilateral congenital ear canal atresia and 17 matched controls. Gray matter volume and thickness were measured in the Heschl's gyrus using Freesurfer. RESULTS: In unilateral congenital ear canal atresia, Heschl's gyrus exhibited cortical thickness asymmetry (right thicker than left, corrected p = 0.0012, mean difference 0.25 mm), while controls had symmetric findings. Gray matter volume and total thickness did not differ from controls with normal hearing. CONCLUSION: We observed cortical thickness asymmetry in congenital unilateral ear canal atresia but no evidence of contralateral cortex atrophy. Further research is needed to understand the implications of this asymmetry on central auditory processing deficits.

[Unusual presentation of a mast cell tumor in the ear canal of a cat]. / Ungewöhnlicher Mastzelltumor im Gehörgang einer Katze.

A 12-year-old male neutered European Shorthair cat was presented for pruritus in the right ear region, bleeding from ear canal and a suspected polyp-like mass in its lumen.After the diagnostic imaging a biopsy of the mass was taken and submitted for histopathological evaluation. Histopathologic examination led to the diagnosis of low grade mast cell tumor. The subsequent staging examinations included ultrasonography of the liver and spleen as well as a complete blood count. Total ear canal ablation was performed on the same day, and the removed ear canal was again submitted for histopathologic evaluation of the surgical margins. The excision incision margins were free from infiltrating tumor cells. The cat was euthanised 14 months after the surgery. It is unknown whether the reasons for this were associated to metastatic spread of the initial mast cell tumor.A mast cell tumor in the ear canal is an unusual and rare finding, however it should be included in the list of differential diagnoses for ear canal tumors.

An Implantable Piezofilm Middle Ear Microphone: Performance in Human Cadaveric Temporal Bones.

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.

A Novel Technique of Reduction Meatoplasty for Correction of Very Large Meatus from a Previous Canal Wall-Down Mastoidectomy.

OBJECTIVE: To evaluate the efficacy of reduction meatoplasty, a novel technique aiming to improve the usage of molded hearing aids and ear plugs in patients undergoing mastoid obliteration of a previous canal wall-down (CWD) mastoidectomy, complicated with a very large meatus. PATIENTS: Twenty-six patients from a tertiary care neurotology clinic with a very large meatus from a previous CWD mastoidectomy, who were unable to use molded hearing aids or ear plugs for water protection. INTERVENTION: Reduction meatoplasty after mastoid obliteration (cartilage strips and bone pate) of the CWD mastoidectomy. The procedure involves removing a wedge of skin and underlying soft tissue superiorly in the meatus. MAIN OUTCOME MEASURES: Reduction in meatus size, enabling usage of hearing aids and ear plugs. RESULTS: Twenty-six patients underwent mastoid obliteration and reduction meatoplasty to reduce meatus size. Patients were followed up for an average of 22 months postoperation. After operation, the meatus size was significantly reduced in all patients, enabling usage of over-the-counter ear plugs. In addition, all six patients with hearing aids could use standard occlusive hearing aid domes without requiring molded hearing aids. No patients showed symptoms of chronic infection in the mastoid cavity during the follow-up period. CONCLUSIONS: Results of reduction meatoplasty showed significant improvements in functionality of the external auditory meatus, indicating that this technique is effective in reducing meatus size and improving the normal meatal anatomy after mastoid obliteration.

Clinical characteristics of intradermal nevus in the external auditory canal.

Melanocytic nevus occurring in the external auditory canal (EAC) is uncommon. Therefore, in the absence of sufficient clinical experience, this disease may be challenging to be suspected even with a physical examination. Herein, clinical and demographic features of intradermal nevus in the EAC were investigated. Patients with an intradermal nevus on histopathological examination (n = 15; 2 men and 13 women; P = .005) were included from a pool of patients who underwent surgical resection for EAC tumors between November 2011 and March 2022. Data were retrospectively collected on their sex, appearance of the lesions, surgical method, and outcomes. Nine patients had a dome shape and 6 patients had a papillomatous shape. Ten patients had dark colors and 5 patients had pale colors. All pale colors appeared only in the dome-shaped nevus, and only dark colored papillomatous nevi were observed. A significant difference was noted in terms of the frequency of occurrence by colors (dark or pale) according to shape (dome or papillomatous) (P = .044). No patient showed recurrence or EAC stenosis after circumferential excision. In women, a dome-shaped or papillomatous mass with dark color in the EAC may likely be predicted as the nevus. However, it can also occur in men, and even if it is a pale color, in the case of a dome shape, taking the nevus into account is important. Moreover, successful treatment outcomes were achieved through circumferential excision.

Malignant myoepithelioma of the external auditory canal - a rare case report with literature review and clinical importance of foramen of Huschke.

BACKGROUND: A malignant myoepithelioma is a rare tumor, mostly arising from the salivary glands. Myoepitheliomas of the ear have rarely been reported. The manuscript reports myoepithelial carcinoma of the external auditory canal (EAC) spreading to the infratemporal fossa. A clinician must be aware of anatomical variation of the bony EAC wall, such as the foramen of Huschke. This rare defect may be a pathway for spreading pathologies between these two anatomical regions. CASE REPORT: We present a case of osteoma-like stenosis of the EAC, which turned out to be an extremely rare malignant tumor. The preoperative MRI and PET/CT revealed that two parts of the tumor communicated through a defect in the antero-inferior portion of the bony ear canal. No distant metastases were detected. Subsequently, the tumor was resected from the ear canal and the infratemporal fossa en bloc. Perioperatively the defect in the EAC wall was suspected of the foramen of Huschke. After the surgery, the older scans of the patient from the past showed no presence of a congenital EAC wall defect. Therefore, the authors concluded that the tumor aggressively grew through the bone due to its biological nature. CONCLUSION: Malignant myoepithelioma of the external auditory canal is an extremely rare condition and could be misdiagnosed as other benign lesions. In cases of suspicious lesions, it is advisable to do a probatory biopsy from the EAC. Surgery is the treatment of choice in malignant myoepitheliomas, and regular follow-ups are essential to monitor for recurrence or metastatic disease. Any mass located at the antero-inferior portion of the EAC wall warrants close evaluation due to its potential for expansion from the EAC.

Multi-Channel Soft Dry Electrodes for Electrocardiography Acquisition in the Ear Region.

In-ear acquisition of physiological signals, such as electromyography (EMG), electrooculography (EOG), electroencephalography (EEG), and electrocardiography (ECG), is a promising approach to mobile health (mHealth) due to its non-invasive and user-friendly nature. By providing a convenient and comfortable means of physiological signal monitoring, in-ear signal acquisition could potentially increase patient compliance and engagement with mHealth applications. The development of reliable and comfortable soft dry in-ear electrode systems could, therefore, have significant implications for both mHealth and human-machine interface (HMI) applications. This research evaluates the quality of the ECG signal obtained with soft dry electrodes inserted in the ear canal. An earplug with six soft dry electrodes distributed around its perimeter was designed for this study, allowing for the analysis of the signal coming from each electrode independently with respect to a common reference placed at different positions on the body of the participants. An analysis of the signals in comparison with a reference signal measured on the upper right chest (RA) and lower left chest (LL) was performed. The results show three typical behaviors for the in-ear electrodes. Some electrodes have a high correlation with the reference signal directly after inserting the earplug, other electrodes need a settling time of typically 1-3 min, and finally, others never have a high correlation. The SoftPulseTM electrodes used in this research have been proven to be perfectly capable of measuring physiological signals, paving the way for their use in mHealth or HMI applications. The use of multiple electrodes distributed in the ear canal has the advantage of allowing a more reliable acquisition by intelligently selecting the signal acquisition locations or allowing a better spatial resolution for certain applications by processing these signals independently.