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As ear-related technologies proliferate, optimizing comfort, retention, and battery life is crucial for enhancing user experience. A thorough understanding of the anatomical interaction between the temporomandibular joint (TMJ) and the earcanal during mouth-opening is essential. This study develops a finite element model and an experimental setup to investigate the biomechanical coupling between the TMJ and the earcanal. We analyze reverse-static deformations, focusing on cartilage-bone junction geometry, mandibular condyle location, and concha mobility. The earcanal geometry is assessed across five cross-sections with seven key dimensions measured. The results indicate that the deformations in cantilever-beam-like models closely match the reference geometry in both approaches, particularly in the lateral region. These findings suggest that a dynamic motion model of the earcanal, accurately simulating its behavior, is feasible.
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Scavenging energy from the earcanal's dynamic motion during jaw movements may be a practical way to enhance the battery autonomy of hearing aids. The main challenge is optimizing the amount of energy extracted while working with soft human tissues and the earcanal's restricted volume. This paper proposes a new energy harvester concept: a liquid-filled earplug which transfers energy outside the earcanal to a generator. The latter is composed of a hydraulic amplifier, two hydraulic cylinders that actuate a bistable resonator to raise the source frequency while driving an amplified piezoelectric transducer to generate electricity. The cycling of the resonator is achieved using two innovative flexible hydraulic valves based on the buckling of flexible tubes. A multiphysics-coupled model is established to determine the system operation requirements and to evaluate its theoretical performances. This model exhibits a theoretical energy conversion efficiency of 85%. The electromechanical performance of the resonator coupled to the piezoelectric transducer and the hydraulic behavior of the valves are experimentally investigated. The global model was updated using the experimental data to improve its predictability toward further optimization of the design. Moreover, the energy losses are identified to enhance the entire proposed design and improve the experimental energy conversion efficiency to 26%.
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Ear-related technologies are spreading in our daily life and have become essential in several applications. The comfort, retention and battery life of in-ear devices can be substantially improved by considering the dynamic behavior of the earcanal. A better understanding of the earcanal dynamic motion would not only result in the improved fit and performance of earpieces but could also pave the way to harvest energy from these movements to power future ear-related technologies. The contours of the left and right ears of 18 healthy subjects during closed mouth and 4 activities (mouth opening, turning head left, raising eyebrows and smiling) were discretized. Eight parameters were analyzed to investigate the possible relation between each of these face-related activities and the radial and axial deformations of the earcanal. The largest significant deformations in reference to the closed-mouth geometry were observed during mouth-opening and smiling at the earcanal entrance and between the two bends.
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Cara , Movimiento , HumanosRESUMEN
OBJECTIVES: This paper aims to validate the performance and physical design of a wearable, unobtrusive ear-centered electroencephalography (EEG) device, dubbed "EARtrodes", using early and late auditory evoked responses. Results would also offer a proof-of-concept for the device to be used as a concealed brain-computer interface (BCI). DESIGN: The device is composed of a custom-fitted earpiece and an ergonomic behind-the-ear piece with embedded electrodes made of a soft and flexible combination of silicone rubber and carbon fibers. The location of the conductive silicone electrodes inside the ear canal and the optimal geometry of the behind-the-ear piece were obtained through morphological and geometrical analysis of the human ear canal and the region around-the-ear. An entirely conductive generic earpiece was also developed to assess the potential of a universal, more affordable solution. RESULTS: Early latency results illustrate the conductive silicone electrodes' capability to record quality EEG signals, comparable to those obtained with traditional gold-plated electrodes. Additionally, late latency results demonstrate EARtrodes' capacity to reliably detect decision-making processes from the ear. CONCLUSIONS: EEG results validate the performance of EARtrodes as a circum-aural and intra-aural EEG recording system adapted for a wide range of applications in audiology, neuroscience, clinical research, and as an unobtrusive BCI.
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Interfaces Cerebro-Computador , Electroencefalografía , Oído , Conducto Auditivo Externo , Electrodos , Potenciales Evocados Auditivos , HumanosRESUMEN
In only a short time, in-ear wearables have gone from hearing aids to a host of electronic devices such as wireless earbuds and digital earplugs. To operate, these devices rely exclusively on batteries, which are not only cumbersome but known for several drawbacks. In this paper, the earcanal dynamic movements generated by jaw activity are evaluated as an alternative source of energy that could replace batteries. A mobile in-ear power sensor device capable of measuring jaw activity metrics is prototyped and tested on three test subjects. The test results are subsequently analyzed using a detection algorithm to detect the jaw activity based on the captured audio signals and to classify them into four main categories, namely chewing, swallowing, coughing and talking. The mean power associated with each category of activity is then calculated by using the pressure signals as measured by a water-inflated earplug subjected to earcanal dynamic movement. The results show that 3.8 mW of power, achieved mainly by the chewing movement, is readily available on average from within the earcanal.
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This paper presents the experimental validation of a readout circuit for the acquisition, amplification, and transmission of extremely weak biopotentials with a focus on electroencephalography (EEG) signals. The device, dubbed CochlEEG, benefits from a low-power design for long-term power autonomy and provides configurable gain and sampling rates to suit the needs of various EEG applications. CochlEEG features high sampling rates, up to 4 kHz, low-noise signal acquisitions, support for active electrodes, and a potential for Wi-Fi data transmission. Moreover, it is lightweight, pocket size, and affordable, which makes CochlEEG suitable for wearable and real-world applications. The efficiency of CochlEEG in EEG data acquisition is also investigated in this paper. Auditory steady-state responses acquisition results validate CochlEEG's capability in recording EEG with a signal quality comparable to commercial mobile or research EEG acquisition devices. Moreover, the results of an oddball paradigm experiment prove the capability of CochlEEG in recording event-related potentials and demonstrate its potential for brain-computer interface applications and electrophysiological research applications requiring higher temporal resolution.