Pressure sensor-based tongue-placed electrotactile biofeedback for balance improvement - Biomedical application to prevent pressure sores formatio
📝 Abstract
We introduce the innovative technologies, based on the concept of “sensory substitution”, we are developing in the fields of biomedical engineering and human disability. Precisely, our goal is to design, develop and validate practical assistive biomedical and/or technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed tactile biofeedback systems. Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); and (2) balance control improvement to prevent fall in older and/or disabled adults. This paper describes the architecture and the functioning principle of these biofeedback systems and presents preliminary results of two feasibility studies performed on young healthy adults.
💡 Analysis
We introduce the innovative technologies, based on the concept of “sensory substitution”, we are developing in the fields of biomedical engineering and human disability. Precisely, our goal is to design, develop and validate practical assistive biomedical and/or technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed tactile biofeedback systems. Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); and (2) balance control improvement to prevent fall in older and/or disabled adults. This paper describes the architecture and the functioning principle of these biofeedback systems and presents preliminary results of two feasibility studies performed on young healthy adults.
📄 Content
HE present paper introduces the innovative technologies, based on the concept of “sensory substitution” [1], we are developing in the fields of biomedical engineering and human disability. Precisely, our goal is to design, develop and validate practical assistive biomedical and/or technical devices and/or rehabilitating procedures for persons with disabilities, using artificial tongue-placed electrotactile biofeedback systems.
Proposed applications are dealing with: (1) pressure sores prevention in case of spinal cord injuries (persons with paraplegia, or tetraplegia); and (2) balance control improvement to prevent fall in older and/or disabled adults.
The tongue-placed electrotactile output device (“Tongue Display Unit” -TDU), on which we focused our attention, was initially introduced by Bach-y-Rita and colleagues [2] and used as a tactile-vision sensory substitution system to provide distal spatial information to blind individuals [3]. It consists in a 2D array of miniature electrodes (12 × 12 matrix) held between the lips and positioned in close contact with the anterior-superior surface of the tongue. A flexible cable connects the matrix to an external electronic device delivering the electrical signals that individually activate the electrodes and therefore the tactile receptors of the tongue (Figure 1A). At this point, however, to provide a perspective for the application of this device outside the laboratory framework and to permit its use over long-time period in real-life environment, this device had to be ergonomically and esthetically acceptable. The current ribbon TDU system did not meet these requirements.
Within this context, with the help of the companies Coronis-Systems and Guglielmi Technologies Dentaires, we have developed a wireless radio-controlled version of the 6 × 6 TDU matrix. This consists in a matrix glued onto the inferior part of the orthodontic retainer including microelectronics, antenna and battery, which can be worn inside the mouth like a dental retainer (Figure 1B). Note that it was decided to reduce by a factor of 4 the overall size of the Bach-y-Rita’s device since the addressed biomedical applications do not require the dense 12 × 12 TDU resolution of the tactile visual substitution systems. The following sections describe the architecture and the functioning principle of our biofeedback systems for:
(1) pressure sores prevention (Section II) and
(2) balance improvement for fall prevention (Section III), and presents preliminary results of two feasibility studies performed on young healthy adults.
A pressure sore is defined as an area of localized damage to the skin and underlying tissues caused by overpressure, shearing, friction or a combination of these factors [4]. Located near bony prominences such as the ischium, sacrum and trochanter, pressure sores present a prevalence from 23% to 39% in adults with spinal cord injuries [5,6] and are recognized as the main cause of rehospitalization for patients with paraplegia [7].
Contrary to healthy individuals, i.e. with intact sensory capacities, individuals with spinal cord injuries (persons with paraplegia, or tetraplegia) do not get the feedback arising from buttock area informing them of a localized excess of pressure at the skin/seat interface and the necessity to make adaptive postural correction to prevent pressure sores [8].
Within this context, we developed an original system for preventing the formation of pressure sores in individuals with spinal cord injuries [9]. Its underlying principle consists in supplying through the wireless 6 × 6 TDU the user with supplementary sensory information regarding the adequate seated posture to adopt to prevent excessive local pressures.
The purpose of the following experiment was to assess the performance of this system in young healthy adults.
Six young healthy males adults (age = 27.2 ± 3.7 years; body weight = 78.2 ± 9.7 kg; height = 181.7 ± 9.1 cm) volunteered for this experiment and gave their informed consent to the experimental procedure as required by the Helsinki declaration (1964) and the local Ethics Committee. None of the participants presented any history of motor problem, neurological disease or vestibular impairment.
Subjects were seated comfortably in a chair onto which was put a pressure mapping system (FSA Seat 32/63, Vista Medical Ltd.), allowing real-time acquisition of the pressure applied on the seat/skin interface. In a preliminary calibration stage, for each subject, we determined the patterns of the pressure distribution (1) in a normal seated posture and (2) in 8 other different postures, corresponding to the situations in which the subject moves his chest in the 8 front, rear, left, right, front-left, front-right, rear-left, rearright directions. The experiment was next initiated. For a period randomly ranged from 15 to 35 seconds, pressures applied to the buttock area of the seated subjects were recorded and overpressures zones were local
This content is AI-processed based on ArXiv data.