Medical Devices : Adaptive design


A Low-Cost, Dosimeter Accessory Kit Enabling the Collection of Accurate Sound Level Measurements from within the Ear Canal

Researchers from the University of Wisconsin – Whitewater in partnership with the Center for Device Design and Development at UW-Fox Valley, have developed a set of low-cost, dosimeter attachments that allow for sound levels to be measured in the ear canal. By combining these novel attachments with commercially available dosimeters, a more accurate reading can be obtained that reflects the true exposure level of potentially harmful noise to the individual. With the current accessory kit, one of three attachments comfortably fits in the user’s ear and connects to a standard dosimeter. Field tests have demonstrated that higher sound levels were recorded at the level of the ear canal using these attachments compared with the traditional method using a shoulder mounted dosimeter.

Foot Harness for Patients Relearning to Walk

UW–Madison researchers have developed a first-of-its-kind foot strap that can attach to training equipment. The strap fits easily and securely around a patient’s own shoe without impeding his or her normal stride. The strap features a safety release mechanism and electronic sensor to stop the exercise if the patient loses balance.

Improved wheelchair design utilizing linear rotary motion with enhanced efficiency and reduced injury and pain for users

An alumnus from the University of Wisconsin-Parkside has developed an alternative to the rim-driven manual wheelchair offering a new and improved mobility device for the physically disabled. T120022 uses lever inputs connected to a patented linear rotary motion (LRM) conversion mechanism providing highly efficient manual power to the wheels without the need of much force. The underlying LRM device is capable of converting a range of linear motion inputs into rotary motion in the chosen direction and efficiently transferring 90% of human biomechanical power to the driven wheels. In addition, the technology is mounted on the base on the wheelchair rather than the wheels, making it more versatile than other lever-drive systems.

Eardrum Nanomembrane Offers Tinnitus Care

UW–Madison researchers have developed a flexible membrane that attaches to the eardrum and detects vibrations. Alternatively, it can be signaled to excite the eardrum.

The nano-thin membrane is made of piezoelectric material. This type of material generates electricity in response to motion, or the reverse, generating motion in response to electricity.

Given this phenomenon, the membrane can be coupled to an antenna and electrodes to act as a transducer, transforming one form of energy into another. Thus, when sound waves strike the eardrum, the shaken membrane produces electrical energy that may be sent out and detected by a transceiver. Conversely, an ingoing radio frequency signal can be received by the electrodes and passed on as audio stimulation to the membrane, causing it to vibrate.

Tactile Button Panel for Use with Touch Screens

UW–Madison researchers have developed a touch screen system that attaches a simple button fixture over a portion of the screen. This is important because virtual ‘buttons’ may be difficult to see or manipulate.

The buttons have clear markings that can be felt by a user. When pressed, the buttons contact the touch screen and the task is performed as usual. The button panel may be mounted permanently or fastened.

Hearing Assistance Device for Improved Fine Structure Processing

A UW–Madison researcher has developed a cochlear implant with an improved processing algorithm that has the potential to provide additional temporal fine structure information to the nervous system, including binaural timing cues. This implant also is expected to improve pitch detection and sound source localization.

The implant comprises an electrode and a processor in communication with the electrode. To generate a stimulating signal for the cochlear implant, the processor receives an acoustic signal, generates a transformed signal, analyzes the transformed signal to identify at least one positive-moving zero crossing (i.e., where the sign of the signal changes from negative to positive) and then triggers an electric current pulse that is delivered to an electrode. This method also can be applied to other hearing assistance devices.

Mechanism for a Braille Watch

UW–Madison researchers have developed a Braille watch to provide the visually impaired with an alternative way to read time. The watch uses small pins to display the time in standard-sized Braille numbers. These pins are seated upon a disk (four pins per disk) with raised and lowered surfaces. When the disk rotates, the pins are translated up or down to reflect a change for each Braille digit and the corresponding time.

One embodiment of the watch comprises a microprocessor, a computer-readable medium, a time display application, a plurality of actuators and one or more buttons to change the mode (hours-minutes, minutes-seconds or month-day). One actuator rotates each disk to adjust the display.

A second embodiment of the watch comprises a single actuator, a plurality of disks, a plurality of pins associated with each disk and an additional pin to indicate a.m./p.m. The disks are linked through one or more gear arms and a plurality of gear teeth, each of which rotates 360 degrees. The actuator controls rotation of the first disk, which in turn controls the rotation of the second disk, etc. The actuator rotates at a constant angular velocity and the system displays the time similarly to the previous embodiment. A third, similar embodiment also is provided; however, it also includes a drive gear that is controlled by the actuator to control the rotation of disk one. These embodiments function similarly to a standard watch, but display the time in standard Braille (depicted in the figure below).

New Touchscreen User Interface Provides Improved Accessibility for Individuals with Disabilities

UW–Madison researchers have therefore developed a complementary feature that works with the tactile keypad and allows users with any residual vision to operate the touch screen directly. This is useful for those with low vision as well as people with any type of reading problem.

The user initially touches the screen anywhere and drags a finger down or across the screen.  When he or she enters into a virtual button while dragging in this fashion, the device automatically switches into a mode where each item entered is highlighted and read aloud (or, more commonly, through headphones). In this fashion a person can move about the screen to have text read or find a desired button. When the desired button is found, the user can just lift the finger and touch the button in the normal fashion.  

While a person who is blind could use this method, it would not be reliable since he or she would not be able to see where the buttons were and could miss one easily. But for users who have difficulty seeing or reading a kiosk, this technique provides them with a much faster method of use. It also is transparent to other kiosk users who can continue to use the kiosk in the regular fashion. 

Adjustable Implant for Treatment of Glottic Insufficiency

UW-Madison researchers have developed an inflatable, adjustable laryngeal implant for the treatment of glottic insufficiency. The implant utilizes an implantable balloon stabilized by a titanium frame. The titanium frame is implanted into the thyroid cartilage of the larynx to provide a mount for the implant and to prevent it from shifting into the airway. The adjustable implant is filled with saline, which pushes the paralyzed vocal fold closer to the functioning fold to restore vocal fold capabilities and alleviate breathing, swallowing and voicing issues. The balloon is filled through a port and valve configuration that also can be used to remove any excess saline, allowing for post-operative adjustment.

Algorithm for Selective Enhancement of Speech Signals

UW-Madison researchers have developed an audio signal enhancement system and method for speech processing, recognition and/or enhancement. Unlike traditional systems, this algorithm recognizes that contrast enhancement, when applied to non-pathological or unimpaired regions of the frequency spectrum, can actually impede a listener’s ability to understand the underlying speech. The system’s contrast enhancement algorithm and selective control mechanism provide a method to selectively manipulate or augment portions of an audio signal and allow other portions to be unenhanced or enhanced differently. As a result, this system can be used to preserve the ability of a listener to process the unenhanced or differently-enhanced portions of the audio signal.

The enhancement process is accomplished by dividing an input auditory signal into a plurality of spectral channels, and either performing or not performing enhancement on established subsets of the channels. Then the enhanced and unenhanced signals are combined to form a selectively enhanced output auditory signal.

Combined Keyboard and System for Improved Accessibility to Electronics

UW–Madison researchers have developed an extension to the EZ Access set of design guidelines, techniques and hardware components. Compact EZ Access keys and functionality can be incorporated into existing or new public information and transaction machines to provide both standard and special keyboard behaviors needed by people with different disabilities. The system incorporates the EZ UP and DOWN, EZ ACTION, EZ BACK and NEXT and EZ HELP buttons of the original EZ Access system into a typical keyboard to improve accessibility of the system and add convenience to users without disabilities. These buttons enhance the functionality of the original arrow and enter keys of a keyboard to allow easy navigation by page, screen or element, while maintaining typical functionalities such as moving the text cursor and typing carriage returns.

Seat with Adjustable Dynamic Joint

The Adjustable Dynamic Joint is a dynamic solution to a static problem. The ability of the ADJ to continuously redistribute stress across muscles and ligaments provides a revolutionary way to significantly reduce the effects of prolonged sitting upon the human frame. The joint, which provides motion in 360 degrees, allows the user to exercise core muscles with natural daily movements. The ADJ can be fitted into seating in a wide range of environments, such as the home, office or car.

Arm Brace for Sonographers to Reduce Wrist Injuries

UW-Madison researchers have developed a spiral splint that acts as a kind of lever to transfer at least some of the force required for medical ultrasound imaging from the hand and wrist to the arm and forearm. The padded splint is fixed to the forearm with two Velcro straps. An ultrasound probe can be flexibly connected to the splint via a lockable, universal ball and socket joint mounted above the sonographer’s hand.

Electromechanical Force-Magnitude, Force-Angle Sensor

UW-Madison researchers have now developed an improved, less expensive force sensor for that device. The new sensor measures force direction from the orientation of a mechanical linkage between a pedal and the base. The linkage moves like a weathervane—always aligning itself with the force. This increases accuracy and simplifies measurement of force direction and magnitude.

The orientation of the linkage is measured to obtain force direction, while strain gages are only used along a single axis to determine force magnitude. This design eliminates several problems inherent in existing multi-axis strain gage systems, such as the need for multiple strain gages along multiple axes, the complex vector mathematics required to use them, the difficulties of calibrating the strain gages and the inaccuracies caused by cross-talk between sensors.

Training Device for Muscle Activation Patterns

UW-Madison researchers have developed a system that specifically trains force direction to restore desired patterns of relative muscle activation in human limbs. The system comprises a training device that includes support for the user, limb engaging surfaces such as handles and/or pedals, and multi axis force sensors to measure the direction and magnitude of applied forces. In addition, a controller provides visual, audio, or kinematic feedback based on the direction of force applied to the handles/pedals. This system also has applications in the enhancement of pedaling efficiency and the strengthening of various targeted muscles.

Oral-Lever Resistance Exercise Device

The researchers have now developed a simpler and cheaper mechanical device that can be used for tongue exercises. The device consists of two levers that fit in the mouth and are connected by a spring or pin joint. During exercise, the user compresses the levers between the tongue and hard palate. Resistance is provided by springs or circular rubber belts similar to o-rings. To make the device more comfortable, the upper lever is custom fit to the hard palate, while the lower lever is adapted to the user’s tongue.

Apparatus for Measuring Contact Pressure between the Tongue and Hard Palate

UW-Madison researchers have developed a mouth-supported device for treating dysphagia, which measures and reports the pressure exerted by the tongue against the hard palate. This apparatus can be used to assess swallowing function and to exercise the tongue muscle. It consists of conductive polymer pressure sensors mounted to a palate-contoured extension of a double mouth guard. The signal is sent through a compact circuit and the output can be displayed digitally or through the use of a tone generator. The device can also be set to signal when the tongue presses hard enough to reach a target pressure.

Spectral Enhancement of Acoustic Signals to Provide Improved Recognition of Speech

UW-Madison researchers have developed a method for enhancing an auditory signal.  The process enhances spectral differences between sounds, minimizing loss of information during amplification of the auditory signal. This is accomplished by dividing the input auditory signal into a plurality of spectral channels, modifying these signals and then combining them to form an enhanced output auditory signal.

Tongue-Placed Tactile Output Device

UW-Madison researchers have developed a tongue-placed tactile output device, which is an improved TVSS that uses the tongue as a stimulation site. Electrotactile stimuli are delivered to the top of the tongue when it contacts a flexible electrode array placed in the mouth. A tongue display unit (TDU), connected to the array by a cable passing out of the mouth, excites individual electrodes on the array according to a spatially-encoded signal from an input source, such as a TV camera. In principle, any input that can be converted into a two-dimensional display by the TDU can reach the brain and become part of a new sensory system.