Device for improving posture, balance and sleep-wake cycles

Abstract

The present invention relates to a wearable device and a vestibular galvanic stimulation method, comprising a housing having a power supply source (40), and a control module comprising: · a current generator (54) configured to produce electrical stimulation signals, · a plurality of electrodes (11, 12) intended to be placed in contact with the skin of the periphery of the ear of a user (100, 200), characterized in that the current generator (54) is configured to produce customized electrical signals on the basis of biometric data collected by one or more integrated or external biophysical sensors (58, 59, 60), the current generator (54) being configured to adjust in real time at least one parameter of the electrical stimulation signals, in particular the intensity and / or the frequency, as a function of the collected biometric data, so as to provide stimulation that is customized to the user. The current generator (54) is configured to implement the automatic search for an optimal level of stimulation intensity maximizing the effectiveness of the stimulation, the optimal level of intensity being chosen less than the perceptual threshold of the user, so as to improve the tolerance and acceptability of the stimulation.

Description

Device for improving posture, balance, and sleep-wake cycles

[0001] The field of invention of this portable vestibular galvanic stimulation device is mainly focused on medicine, neurology and sensory and cognitive rehabilitation technologies.

[0002] With age, sensory and motor abilities decline, affecting the quality of life of older people. Corrective devices such as glasses and hearing aids can compensate for vision and hearing loss, but there is still no standardized solution to compensate for the loss of vestibular function, which is crucial for posture and balance.

[0003] Age-related balance problems are common and increase the risk of falls, which are a leading cause of serious injury and death among seniors. Furthermore, sleep cycles are often disrupted with age, leading to insomnia, fragmented sleep, and periods of daytime sleepiness, exacerbating alertness and balance issues.

[0004] Impact on the lives of seniors

[0005] Deteriorating sensory abilities and impaired sleep quality have major repercussions on the independence and safety of older adults. Decreased balance increases the risk of falls, often followed by injuries that can lead to loss of mobility or self-confidence. Sleep disturbances, meanwhile, affect concentration, memory, and alertness, diminishing the quality of life of seniors and their ability to maintain an active social life. The cumulative effect of these factors leads to a loss of independence and increases the need for assistance, which also impacts their psychological and social well-being.

[0006] Patients with Parkinson's disease experience motor impairments exacerbated by postural instability. This neurological condition impairs voluntary movements, leading to precarious balance and a significantly increased risk of falls. Decreased vestibular function and loss of stability also affect the sleep-wake cycle. These patients often suffer from sleep disturbances, reduced daytime alertness, and disruptions to their circadian rhythm. In this context, devices designed to improve postural stability and resynchronize the sleep-wake cycle offer an opportunity to reduce the risk of falls and improve the quality of life for people with Parkinson's disease.

[0007] More specifically, the invention falls within the fields of vestibular rehabilitation to treat disorders related to the vestibular system, such as postural imbalances, spatial orientation disorders and vertigo by galvanic vestibular stimulation (GVS) to modulate neural signals related to balance, posture and cognitive functions.

[0008] It is designed to meet the needs of elderly or vulnerable populations, by reducing the risk of falls and improving independence.

[0009] The invention also relates to the field of regulating sleep-wake cycles by addressing problems related to circadian rhythm disorders, particularly in individuals suffering from insomnia, chronic fatigue or jet lag.

[0010] The scope of the invention covers both therapeutic applications (treatment of pathologies), preventive applications (reduction of fall risks) and improvements in cognitive and motor performance in a medical and everyday context. State of the art

[0011] The prior art includes US patent application 2016 / 0045733, which describes a portable vestibular galvanic stimulation device comprising a current generator and electrodes placed around the ears, designed to influence the vestibular system. The device implements a feedback loop primarily aimed at maintaining stable and safe electrical stimulation, notably through the measurement of electrical parameters such as impedance or effective current at the electrode-skin interface. The objective of this known solution is to ensure the reliability and safety of the stimulation, regardless of variations in contact or skin resistance, without directly taking into account the user's overall physiological state.

[0012] Application WO 2023 / 156591 describes a vestibular stimulation system implementing adaptive stimulation protocols based on the analysis of physiological signals, particularly in a clinical or experimental setting. This known device relies on the acquisition and processing of neurophysiological data to define or adjust stimulation parameters according to predefined models or protocols. The emphasis is on methods for therapeutic personalization and the optimization of neurological effects, with an architecture geared towards controlled, often supervised, uses, without a detailed description of a standalone wearable device intended for prolonged daily use.

[0013] US patent application 2021 / 0361943 describes multisensory neuromodulation systems and methods, including stimulation devices applied near the ears, capable of generating complex electrical waveforms (galvanic, caloric, audio, or combined). D3 emphasizes sophisticated signal generation and modulation (amplitude, frequency, modulation), as well as advanced control architectures, primarily in a therapeutic or experimental setting. While the document mentions control systems and adaptable parameters, the main focus is on the design of effective signals, not real-time adaptation based on the user's overall physiological state under everyday usage conditions.

[0014] US patent application 2020 / 0345970 describes a portable auricular stimulation device for therapeutic or wellness applications, comprising electrodes positioned near the ear and an electronic control circuit. The device may incorporate communication and control functions allowing the selection or modification of stimulation parameters according to predefined modes. This prior art solution primarily emphasizes the ergonomics of the ear support, the versatility of the stimulation modes, and integration into a digital ecosystem, without describing continuous and automatic adaptation of the stimulation based on real-time analysis of the user's physiological data. Disadvantages of prior art

[0015] Prior art patents describe galvanic vestibular stimulation (GVS) devices designed to improve balance and posture. These devices are intended for laboratory use in clinical research and involve electrode implantation in complex configurations, unsuitable for everyday use by individuals living in normal daily life. They are not discreet enough for continuous use in the daily lives of users, particularly the elderly or those with neurodegenerative diseases.

[0016] Existing solutions implement standardized stimulation parameters without adapting them to each user's specific needs. They fail to consider individual motor and sensory thresholds, thus optimizing therapeutic efficacy.

[0017] Furthermore, the ability to monitor and adjust stimulation based on the user's physiological responses with prior art solutions is very limited.

[0018] Documents D1 to D4 each describe, to varying degrees, portable or semi-portable vestibular galvanic stimulation devices employing a current generator and electrodes positioned near the ears. However, these devices share a common residual problem that is not satisfactorily resolved by the prior art.

[0019] In particular, US 2016 / 0045733 focuses on electrotechnical regulation of the delivered current, primarily aimed at compensating for impedance variations at the electrode-skin interface to ensure signal stability and safety. This approach, while necessary, does not take into account the user's actual physiological state, nor how this changes over time, especially during prolonged use.

[0020] D2 and US 2021 / 0361943 explore approaches to personalization or advanced signal generation in predominantly experimental or clinical settings, but without offering continuous and autonomous adaptation in everyday life conditions, nor consistent integration into a wearable device intended for extended wear. Adjustments are mainly linked to predefined protocols or models, rather than a user-centered, real-time biometric adaptation loop.

[0021] US patent application 2020 / 0345970, meanwhile, emphasizes the ergonomics of the ear support and the selection of stimulation modes, but does not go beyond a logic of manual adjustment or predetermined profiles, without automatic adaptation based on continuously measured physiological data.

[0022] Unlike a simple motion measurement intended to detect instability, the invention implements an automatic calibration based on stochastic resonance in which an IMU sensor is used to evaluate the effectiveness of an nGVS stimulation in order to optimize its level under a tolerance constraint, which does not obviously follow from a simple safety regulation or electrical control of the current.

[0023] Thus, prior art remains limited to devices that are either technically regulated or configurable, but unable to functionally adapt the stimulation to the user according to their instantaneous physiological state, which in practice translates into variable effectiveness, sometimes limited tolerance and difficulty of prolonged use. Solution provided by the invention

[0024] The claimed invention addresses this remaining problem by proposing a portable vestibular galvanic stimulation device in which the current generator adjusts the stimulation parameters, including intensity and / or frequency, in real time based on biometric data from integrated or external biophysical sensors. This biometric adaptation provides personalized, dynamic, and evolving stimulation that is better tolerated by the user and more effective over time, going beyond simple electrical signal regulation.

[0025] In this sense, the invention operates a change in functional logic, moving from signal stabilization to user-centered physiological adaptation, and provides a coherent and non-obvious technical solution to the problem not solved by known solutions in the prior art.

[0026] To overcome these drawbacks, the present invention relates to a portable vestibular galvanic stimulation device having the characteristics of claim 1. It includes, in particular, a housing comprising a power supply, and a control module comprising: a current generator configured to produce electrical stimulation signals, a plurality of electrodes intended to be placed in contact with the skin around the ear,

[0027] The current generator is configured to produce customized electrical signals based on biometric data collected by one or more integrated or external biophysical sensors.

[0028] This current generator is configured to generate electrical signals with an amplitude between 0.1 mA and 10 mA and / or to generate electrical signals with a frequency between 0.1 Hz and 200 Hz.

[0029] The control module executes a closed-loop adaptation algorithm to adjust stimulation parameters in real time based on data measured by sensors, including brain activity or heart rate sensors, and / or movement sensors.

[0030] The device includes an automatic calibration system to detect electrode impedance and adjust stimulation parameters according to the wearer's skin characteristics.

[0031] A sleep-wake cycle detection module allows stimulation to be applied during specific sleep phases in order to improve rest quality and memory consolidation.

[0032] The wireless communication module is configured to transmit collected data and stimulation parameters to a mobile application or cloud platform for monitoring and analysis.

[0033] The electrodes are mounted on a helmet, a band, or any other ergonomic support allowing precise positioning on the mastoid or temporal regions of the skull.

[0034] The electrodes are integrated into lateral brackets shaped like a hook or a clip, configured to fit the rear contour of the ear.

[0035] The invention also relates to a method of vestibular galvanic stimulation implemented by a device referred to above, comprising the following steps: collection of physiological and biometric data of the wearer using integrated or external sensors, analysis of the data collected to determine the optimal stimulation parameters, generation and application of an electrical current through the electrodes to induce vestibular galvanic stimulation, adjustment of the stimulation parameters in real time according to the physiological responses of the wearer.

[0036] Biometric data includes information related to balance, posture, heart rate, or brain activity.

[0037] The stimulations are synchronized with external stimuli, including visual, auditory or vibratory signals, to enhance immersion in virtual experiences or rehabilitation environments.

[0038] Detailed description of a non-limiting example of implementation

[0039] The present invention will be better understood upon reading the following description, concerning a non-limiting example of an embodiment illustrated by the accompanying drawings where:

[0040] The figure represents a schematic view of an elderly person wearing a vestibular galvanic stimulation device according to the invention.

[0041] The figure represents a schematic three-quarter front perspective view of a vestibular galvanic stimulation device according to the invention.

[0042] The figure represents a schematic front view of a vestibular galvanic stimulation device according to the invention.

[0043] The figure represents a schematic three-quarter rear perspective view of a vestibular galvanic stimulation device according to the invention.

[0044] The figure represents a schematic front view of a vestibular galvanic stimulation device according to one embodiment of the invention.

[0045] The figure represents a schematic diagram of the electronic circuit for vestibular galvanic stimulation according to the invention. General principle of the invention

[0046] The general principle of the invention relates to the use of a portable vestibular galvanic stimulation device to improve balance, postural stability, and the synchronization of sleep-wake cycles, particularly for the elderly or those suffering from diseases such as Parkinson's, and to enhance the quality of life and autonomy of users.

[0047] To achieve this, the device is equipped with electrodes that deliver very weak electrical impulses to the back of your ears. These impulses mimic the natural signals that your brain receives from your vestibular system (responsible for balance and spatial orientation).

[0048] The invention is based on the observation that simple electrical regulation of vestibular stimulation is insufficient to guarantee lasting effectiveness and good tolerance during prolonged use. The invention therefore proposes real-time biometric adaptation of stimulation parameters, based on physiological data measured in the user, within a self-contained portable device.

[0049] Hardware configuration of the portable vestibular galvanic stimulation device

[0050] The portable device is configured to allow precise and stable positioning of the electrodes on the user's mastoid areas (100, 200), in a comfortable manner so as not to create irritating pressure or friction, and maintaining correct application even in the event of untimely head movements (110, 210) of the patient (100, 200).

[0051] For this purpose, the device includes a hoop (10, 20) extending between the right and left mastoid areas of the user (100, 200), passing respectively over the skull or under the chin.

[0052] In the embodiment examples described with reference to figures a, the device is equipped with a wide hoop (10) which surrounds the top of the head (110), extending from the frontal region towards the back of the skull.

[0053] This headband (10) is lightly padded or textured on the part in contact with the scalp to improve comfort and reduce pressure during prolonged use. It is made, for example, of a semi-flexible material (such as plastic or a combination of lightweight metal and foam), allowing for an ergonomic fit to different head shapes.

[0054] The stimulation electrodes (11, 12) are positioned on each side of the head, at the level of the mastoid areas (just behind the ears), a suitable location for effectively targeting the vestibular system. These electrodes (11, 12) are integrated into lateral supports (15, 16) shaped like a hook or clip, configured to conform to the rear contour of the auricle and providing good fixation to the skin.

[0055] The contact surfaces of the electrodes (11, 12) are flat, to maximize the contact area with the skin and ensure efficient transmission of galvanic currents.

[0056] These electrodes (11, 12) could be coated with a conductive material (gel or carbon) or use moistened pads to improve electrical conductivity and minimize skin irritation.

[0057] The supports (15, 16) for the electrodes (11, 12) are height-adjustable and slightly articulated, allowing precise positioning and adaptation to different head morphologies.

[0058] The headband (10) and the parts in direct contact with the skin are designed to provide a comfortable fit, which is essential for prolonged or repeated use. It consists of two retractable sections allowing for coverage over a variable length, secured by a reversible hook-and-loop fastener of the "VELCRO"™ type, with regularly spaced perforations allowing locking in the desired extension by a tab engaged in the appropriate perforation.

[0059] The contact areas (upper headband and electrode supports) are padded or rounded to avoid pressure points.

[0060] The flexible band with a vertical adjustment system, indicated by a two-way arrow, allows the headband height to be adjusted to fit different head sizes. This adjustment ensures correct electrode positioning and optimal comfort.

[0061] The design ensures that the device stays securely on the head, even during moderate movements, thanks to the wrap-around structure and the well-secured electrode supports.

[0062] This device is designed to be easily portable, with a lightweight structure and no bulky components.

[0063] The figure illustrates a variant embodiment where the hoop (10) supports two pads (13, 14) mounted in a way that can be oriented with respect to the ends of the hoop (10) and having electrodes (11, 12) on their surface.

[0064] Variant of biometric adaptation

[0065] According to a preferred aspect, biometric adaptation does not consist of a simple proportional adjustment or electrical regulation of the signal, but of an individual calibration by searching for an optimal level of nGVS stimulation based on the principle of stochastic resonance, in which the intensity of stimulation is swept or modified iteratively in order to identify, for each user, a level maximizing a postural stability indicator extracted from inertial measurements (IMU).

[0066] Advantageously, this calibration is carried out in such a way as to select a level of stimulation below the individual perceptual threshold, in order to improve tolerance, acceptability, and allow prolonged wear in real-life conditions. Application

[0067] This device is designed for specific uses, such as: Vestibular rehabilitation: To treat or compensate for balance disorders by stimulating the vestibular nerves. Improvement of cognitive and motor functions: Can be used to synchronize brain activity or improve motor coordination in therapeutic settings. Immersive sensory simulation: Integrated into virtual or immersive environments to influence spatial perception or treat neurological disorders.

[0068] A connected device includes an electronic circuit to deliver a weak, controlled electrical current through the electrodes. This current can be adjusted in terms of intensity and frequency to suit therapeutic needs. Signals applied to the electrodes

[0069] By using galvanic vestibular stimulation (GVS) and its variant with stochastic noise (nGVS), the device enhances vestibular responses to stabilize posture and reduce the risk of falls.

[0070] It acts on the perception of orientation (egomotion) and optimizes the ability of the vestibular system to integrate sensory signals.

[0071] In a preferred mode, nGVS stimulation is applied at an intensity below the individual perceptual threshold, typically between 0.025 mA and 0.300 mA, which allows the stochastic resonance to be exploited without generating bothersome skin sensations. Synchronization of sleep-wake cycles:

[0072] The device helps stabilize circadian rhythms by stimulating neural circuits linked to the suprachiasmatic nucleus (SCN), the main regulator of sleep-wake cycles. Adjustable intensity is applied to maintain daytime alertness or promote nighttime relaxation. Cognitive and functional improvement:

[0073] The stimulation acts indirectly on NMDA receptors in the hippocampus, promoting cognitive plasticity and learning. It improves alertness, attention, and memory by strengthening cholinergic networks.

[0074] The device is individually calibrated for each user, adjusting the stimulation parameters according to the detected motor and sensory thresholds.

[0075] It is equipped with an IMU (Inertial Measurement Unit) sensor to track movements in real time and dynamically adjust the stimulation according to the user's needs.

[0076] The device measures biological parameters such as heart rate and respiration using integrated sensors. Based on this data, it adjusts the intensity and frequency of electrical impulses to provide you with a customized stimulation. Potential applications:

[0077] Some studies show that vestibular stimulation helps improve attention and concentration. This invention can be used to treat certain balance disorders or sleep disturbances. Vestibular galvanic stimulation is a non-invasive method, meaning it does not require surgery.

[0078] Each person reacts differently to stimulation, which is why the ability to adapt the parameters based on individual biological data is a major advantage. The potential applications of this technology are numerous and could revolutionize the way we treat certain conditions. Electronic circuit

[0079] The electronic circuit of the portable galvanic vestibular stimulation device is designed to provide precise and adjustable electrical stimulation to the vestibular system.

[0080] It includes a power supply consisting of a rechargeable lithium-ion battery (50) associated with an intelligent battery management circuit (51) integrating in a known manner a charge regulator, a voltage converter (“buck / boost”) to adjust the voltage to levels suitable for the other components, and protection mechanisms against overcharge and deep discharge.

[0081] The electronic circuit is built around a microcontroller (52) which coordinates the overall operation of the circuit, manages user commands and stimulation parameters.

[0082] A user interface (53) including buttons, a screen or LEDs to enable configuration of stimulation modes and display information on operation and connected to the microcontroller (52).

[0083] The electronic circuit optionally includes wireless modules (Bluetooth or Wi-Fi) for synchronization with mobile applications or remote control.

[0084] The microcontroller (52) drives an electrical signal generator (54) including, for example, a digital-to-analog converter (DAV) which converts the digital signals from the microcontroller (52) into analog signals to modulate the stimulation currents.

[0085] Operational amplifiers (55) are used to adjust the output signal level and ensure high accuracy and stability. Analog filters (56) suppress unwanted interference and harmonics, ensuring that the signal applied to the electrodes is clean and accurate.

[0086] The stimulation module (56) includes a constant current generator that provides a precise and stable current to the electrodes, regardless of variations in skin resistance. It optionally includes electrode selectors consisting of multiplexers or analog switches to direct the current to the selected electrodes. For patient protection, current and voltage limiting circuits prevent any risk of overcurrent or electrocution.

[0087] A measurement and feedback module (57) manages data acquisition. It includes biopotential amplifiers to measure physiological signals, such as brain activity (EEG) from, for example, a wristband equipped with a sensor (58), or eye movements (EOG) from a sensor (59). This module (57) typically includes an analog-to-digital converter to digitize the measured signals for processing by the microcontroller (52).

[0088] The circuit may include additional sensors, notably a 3D accelerometer (60) to monitor head movements and posture. This could be a smartphone (60) incorporating such a 3D accelerometer or a smartwatch incorporating a 3D accelerometer, communicating via a teletransmission module (61), for example, using the Bluetooth protocol.

[0089] It may also include an impedance sensor to measure the quality of electrode contact.

[0090] The electronic circuit also includes safety circuits ensuring galvanic isolation to prevent stray currents from passing through the device in case of failure and fault detectors that monitor overloads, short circuits or electrode connection errors.

[0091] It usually includes external interfaces such as a USB-C connector: Used for charging, updating proprietary software or communicating with a computer and / or wireless connection, such as a Bluetooth or Wi-Fi module to transfer data or receive commands from a mobile application or software.

[0092] The electrodes (63) are made of biocompatible materials and are connected to the stimulation module to apply current to targeted areas behind the ears. They are typically wet electrodes (with conductive gel) or dry electrodes (with special features for increased conductivity). Functioning

[0093] The operation can be summarized by the following main steps: Initialization: The microcontroller initializes the device, checks the connections and battery levels. Configuration: The user selects the parameters via the interface (intensity, frequency, duration). Stimulation: The signal is generated by the DAC, adjusted by the amplifiers, and applied to the electrodes via the current generator. Feedback: Sensor measurements are analyzed to adjust parameters in real time and optimize stimulation. Safety: Circuits continuously monitor conditions to ensure safe operation.

[0094] The initialization and configuration steps involve powering on the device: The user activates the device via a button or a touch interface (53). The microcontroller (52) initializes, checks the electrode connections, battery status, and circuit integrity. The user configures the stimulation parameters, such as current intensity, signal frequency, and session duration. A graphical interface on a screen or via a mobile application allows for intuitive control.

[0095] The next step involves preparing the electrodes: The electrodes are placed behind the ears (mastoid areas) or in specific positions defined by the protocol by placing the aforementioned mobile device on the user's skull. An integrated impedance sensor measures the quality of contact between the electrodes (11, 12) and the skin. In case of poor contact, an error message is displayed, and the user is prompted to adjust the electrodes.

[0096] The generation of the electrical stimulation ensures the production of the signal: the signal generator (54), controlled by the microcontroller (52), produces a low-intensity (<10 mA) electrical current with a configurable frequency (0.1 Hz to 200 Hz). Available signal shapes include: sinusoidal, square, ramps, or dynamically adapted random signals.

[0097] Real-time measurements (e.g., EEG, EOG, accelerometers) are used to modulate signal parameters to adapt the stimulation according to the user's physiological response. The current is transmitted to the electrodes (11, 12) via a constant current generator circuit and an adaptive amplifier (54, 55), ensuring stable stimulation even in the event of impedance variations.

[0098] The electronic circuit provides real-time feedback based on physiological measurements: The device integrates sensors (EEG, EOG, accelerometer, position sensors) that record the patient's physiological responses.

[0099] The data measured includes brain activity (EEG), eye movements (EOG) and user posture or balance (accelerometer).

[0100] A signal processing module compares the measured data to reference values ​​or predefined thresholds. If necessary, it adjusts the stimulation parameters (intensity, frequency) to optimize the therapeutic effect.

[0101] The device continuously monitors the applied current and automatically stops stimulation if safety thresholds are exceeded (excessive current or voltage). If malfunctions are detected (poor contact, excessive impedance), an alert is displayed and stimulation is suspended. Galvanic isolation protects the user from any electrical risk.

[0102] All measured data and stimulation parameters are recorded for later analysis. The device can transmit the collected data to a mobile app or computer via Bluetooth, Wi-Fi, or USB for medical monitoring or research. The user receives information about the session's progress (remaining time, stimulation level) via a screen or app.

[0103] Once the programmed duration has elapsed, the device gradually reduces the intensity to avoid a sudden power interruption and records the session data. It indicates to the user that the stimulation is complete via an audible signal or a visual message. The user can then safely remove the electrodes and switch off the device.

[0104] The device offers several predefined protocols depending on the applications (rehabilitation, motion sickness, cognitive improvement). Typical application

[0105] This device is particularly suitable for: Vestibular rehabilitation: Reduction of balance disorders. Cognitive improvement: Synchronization with brain signals to optimize certain functions. Sleep improvement: Galvanic Vestibular Stimulation (GVS) and synchronization of the sleep-wake cycle.

[0106] Custom calibration mode: The device is individually calibrated for each user before continuous use. The calibration process includes the following steps:

[0107] Evaluation of the perceptual threshold and determination of a sub-threshold range: calibration begins with a determination of the individual perceptual threshold, by progressively increasing a low-intensity stimulation until a sensation perceptible to the user appears.

[0108] The therapeutic stimulation is then determined in a range below the threshold, typically between 0.025 mA and 0.300 mA, in order to avoid unpleasant skin sensations and to allow prolonged use.

[0109] Directionality test: The device is calibrated to optimize responses in the anteroposterior and lateral axes. Responses to different directions are observed, and the data is analyzed to configure the preferred directional stimulation for each user, targeting cortical areas such as V6, SDA, and ITC, which are involved in orientation perception and stability.

[0110] Calibration of circadian and stochastic noise parameters (nGVS): Finally, calibration of circadian parameters allows for adjustment of the stimulation for optimized daytime alertness and nighttime relaxation. The device is also calibrated to adjust the noise frequency (nGVS), which improves stochastic resonance and helps stabilize posture.

[0111] Structure and design of the device (Bilateral electrodes on the mastoids):

[0112] The device incorporates two electrodes (11, 12), made of conductive silicone or silver / silver chloride, positioned on the mastoid processes to apply symmetrical stimulation to vestibular afferents. These electrodes (11, 12) are configured to induce directional stimulation tailored to the individual user's needs. Anteroposterior stimulation activates cortical pathways associated with egomotion and orientation, while lateral stimulation enhances overall balance perception.

[0113] Stimulation Intensity and Frequency Modulation Circuit: This circuit allows for real-time modulation of intensity and frequency. Depending on the direction of stimulation, it adjusts the parameters to target cortical responses in standard GVS or nGVS. Anteroposterior stimulation activates areas V6, SDA, and ITC, associated with directional movement, while lateral stimulation promotes a multisensory response in areas such as CSV, which integrates vestibular signals in a balanced way.

[0114] Specific stimulation parameters and modulations

[0115] Current density and directional modulation for visuo-vestibular integration: Stimulation intensity can be varied to effectively activate vestibular afferents. Anteroposterior stimulation is calibrated to indirectly activate cortical areas involved in directional perception, while lateral stimulation promotes global signal integration across multisensory areas. This contributes to orientation perception and directional stability.

[0116] Noise frequency for stochastic resonance and continuous stimulation: The device uses adjustable white noise between 0.1 and 640 Hz to optimize the detection of weak signals in the vestibular receptors. This noise promotes the integration of sensory information by amplifying input signals, thereby enhancing stability and the ability to perceive orientation in everyday environments.

[0117] Modulation of synaptic responses and NMDA receptors for cognitive plasticity

[0118] Indirect influence on NMDA receptors and hippocampal LTP: GVS stimulation does not directly target NMDA receptors in the hippocampus but influences them indirectly via vestibular polysynaptic pathways. Activation of these pathways transmits signals to the brain, which propagate to the hippocampus, facilitating LTP and enhancing spatial memory and learning. This promotes cognitive plasticity, which is essential for orientation and navigation.

[0119] Enhancement of cholinergic activity and P1 / N1 EEG components: Continuous stimulation improves attention and alertness through indirect activation of cholinergic networks, thereby strengthening the P1 and N1 EEG components. By optimizing attention, the device allows the user to improve their responsiveness to environmental stimuli, thus contributing to better visuo-vestibular integration and cognitive stability.

[0120] Real-time measurement and analysis of motor and postural responses

[0121] IMU sensor for tracking movement and postural stability: The device integrates an IMU (Inertial Measurement Unit) sensor, including a gyroscope, accelerometer, and magnetometer, to monitor the user's movements and postural changes in real time. This sensor measures changes in head orientation, allowing the device to detect modifications in posture and movement. The IMU data enables dynamic adjustments to the stimulation based on stability and orientation needs.

[0122] Advantageously, the inertial signals measured by the IMU are processed to extract at least one metric representative of postural stability, such as sway amplitude, angular variance, spectral energy, or a composite indicator. This metric is used as an objective function in an automated calibration procedure, aiming to select an nGVS intensity that maximizes the measured effect while remaining below the perceptual threshold.

[0123] Dynamic adaptation via tracking algorithm: IMU data is analyzed using an integrated tracking algorithm, which compares movements to reference thresholds defined during initial calibration. The algorithm automatically adjusts the intensity and frequency to respond to postural changes. This adjustment, occurring in less than 20 ms, ensures optimal responsiveness, particularly in the event of sudden imbalance or unexpected movement.

[0124] Analysis without CoP for postural stability: Although direct measurement of the Center of Pressure (CoP) is not possible, IMU sensor data provides an indirect estimate of stability and the necessary adjustments. This information allows the device to modulate stimulation to maintain the user in a stable position, particularly during rotational movements or changes of direction.

[0125] Continuous stimulation and circadian synchronization for prolonged and optimized effects

[0126] Recent studies have demonstrated that galvanic vestibular stimulation (GVS) can stabilize certain sleep parameters, including sleep efficiency and total sleep duration, by indirectly influencing the sleep-wake cycle. With regular GVS application, observed effects include improved regulation of sleep-wake cycles and enhanced cognitive flexibility, particularly beneficial for daytime alertness. By activating vestibular afferents, GVS acts on neural circuits connected to the suprachiasmatic nucleus (SCN), the center for regulating circadian rhythms.

[0127] Stabilization of sleep parameters: Vestibular stimulation has demonstrated its potential to stabilize key aspects of sleep, such as sleep efficiency and total sleep time. This stability helps reduce sleep interruptions, thus promoting better nighttime recovery and increased alertness during the day.

[0128] Impact on cognitive flexibility and executive functions: In addition to improving sleep quality, GVS also appears to enhance cognitive flexibility, which is linked to a more stable synchronization of the activity-rest rhythm. This improvement suggests that GVS could have positive effects on overall cognitive performance, thanks to more efficient regulation of sleep-wake cycles.

[0129] The stimulation is automatically adjusted according to the user's sleep-wake cycles. During the day, a higher intensity is applied to promote alertness and attention. In the evening and at night, the stimulation decreases to promote relaxation, facilitating a stable sleep-wake cycle, an important factor for cognitive health and well-being. Mobile app and smart tracking

[0130] Mobile app for personalized monitoring and adaptive learning: The device comes with a mobile app that records and analyzes real-time data on postural responses and movement variations. This data allows for automatic adjustment of stimulation parameters based on the user's specific needs. The app provides information on stability and posture trends, enabling the user (or a healthcare professional) to monitor the device's effectiveness.

[0131] Continuous personalization and adjustments based on user data: The data collected by the application allows for constant personalization of the stimulation. Adjustments, whether for frequency, intensity, or type of stimulation (GVS or nGVS), are based on the user's individual responses, ensuring constant adaptability to maintain optimal effects as needs evolve.

[0132] Alerts and tracking notifications: The mobile app sends reminders and alerts to indicate optimal usage times, as well as to report any postural response abnormalities. In the event of significant changes in the user's movements or stability, the app may recommend adjustments or a consultation with a healthcare professional.

[0133] Reports and long-term monitoring: The application generates monitoring reports that summarize data on improvements in posture, stability, and sleep-wake cycle. These reports, accessible to the user or a healthcare professional, provide a comprehensive overview of progress and allow for adjustments to parameters to maximize the device's long-term effects.

Claims

Portable vestibular galvanic stimulation device, comprising a housing including a power supply (40), and a control module comprising: a current generator (54) configured to produce electrical stimulation signals, a plurality of electrodes (11, 12) intended to be placed in contact with the skin around the ear, characterized in that said current generator (54) is configured to adjust in real time at least one parameter of said electrical stimulation signals, in particular the intensity and / or frequency, according to biometric data collected by one or more integrated or external biophysical sensors (58, 59, 60) integrated into the device and / or external, so as to provide personalized stimulation to the user. Device according to claim 1, characterized in that said current generator (54) is configured to implement individual calibration of galvanic vestibular stimulation comprising nGVS stochastic noise stimulation, said calibration being based on a stochastic resonance principle, and comprising: the acquisition, by means of an IMU-type inertial sensor, of data representative of the balance and / or postural stability of the user, the determination, from said data, of at least one metric of stimulation effectiveness, the automatic search for an optimal level of stimulation intensity maximizing said metric, and in that the optimal intensity level thus determined is chosen to be below the user's perceptual threshold, so as to improve the tolerance and acceptability of the stimulation. Device according to claim 1 characterized in that said biophysical sensors comprise at least one sensor selected from an EEG type brain activity sensor, an EOG type eye movement sensor, and an IMU type inertial sensor comprising an accelerometer and / or a gyroscope, and in that the data from said sensors are used to adjust the stimulation parameters in real time. Device according to any one of the preceding claims, characterized in that said current generator (54) is configured to automatically adapt at least the intensity of the stimulation according to the user's sleep-wake cycles, so as to promote alertness during daytime phases and relaxation during nighttime phases. Device according to any one of the preceding claims characterized in that said current generator (54) is configured to generate electrical signals having an amplitude between 0.1 mA and 10 mA. Device according to any one of the preceding claims characterized in that said current generator (54) is configured to generate electrical signals having a frequency between 0.1 Hz and 640 Hz. Device according to any one of the preceding claims, characterized in that the control module executes a closed-loop adaptation algorithm to adjust the stimulation parameters in real time according to the data measured by the sensors, including brain activity or heart rate sensors (58), and / or movement sensors (60). Device according to any one of the preceding claims, characterized in that it includes an automatic calibration system to detect the impedance of the electrodes and adjust the stimulation parameters according to the characteristics of the wearer's skin. Device according to any one of the preceding claims, comprising a sleep-wake cycle detection module, enabling the application of stimulation during specific sleep phases in order to improve rest quality and memory consolidation. Device according to any one of the preceding claims, wherein the wireless communication module is configured to transmit the collected data and stimulation parameters to a mobile application or cloud platform for monitoring and analysis. Device according to any one of the preceding claims characterized in that the electrodes (11, 12) are mounted on a helmet, a band, or any other ergonomic support allowing precise positioning on the mastoid or temporal regions of the skull. Device according to any one of the preceding claims characterized in that said electrodes (11, 12) are integrated into lateral supports (15, 16) in the form of a hook or clip configured to fit the rear contour of the auricle of the ear. Device according to any one of the preceding claims, characterized in that it is configured to perform an individual calibration of an nGVS type stimulation based on stochastic resonance, comprising an automatic search for an optimal intensity level, determined from at least one metric extracted from the data of an IMU type inertial sensor, said calibration being carried out so as to select an intensity below the user's perceptual threshold. A method of vestibular galvanic stimulation implemented by a device according to any one of claims 1 to 13, comprising the following steps: collection of physiological and biometric data of the wearer using integrated or external sensors, analysis of the collected data to determine the optimal stimulation parameters, generation and application of an electrical current through the electrodes to induce vestibular galvanic stimulation, adjustment of the stimulation parameters in real time according to the physiological responses of the wearer. A method according to the preceding claim, characterized in that the biometric data includes information relating to balance, posture, heart rate or brain activity. A method according to any one of claims 14 or 15, wherein the stimulations are synchronized with external stimuli, including visual, auditory or vibratory signals, to enhance immersion in virtual experiences or rehabilitative environments. A method according to any one of claims 14 to 16, characterized in that it comprises an individual calibration step by stochastic resonance of an nGVS stimulation, in which several intensity levels are automatically tested or adjusted and an optimal level is selected according to a metric from an IMU inertial sensor, while requiring that the selected intensity remains below the user's perceptual threshold.

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