Medical Device Design & Equipment Development

(via The Institute for Intelligent Systems and Robotics (ISIR))

Technology that helps robots navigate and interact with their environment may soon help blind people in much the same way. A new type of glasses that takes advantage of 3D navigation that some robots use are currently being designed by Edwige Pissaloux and his team from the Institute of Intelligent Systems and Robotics located in France. The design uses a headset imaging system that takes 3D images and sends them to a handheld device that converts it to braille that the user can read which gives the blind a different way to see their environment. The headset consists of two cameras mounted on either side of the wearer which in tandem takes 3D images. A processor then analyzes the images and identifies various objects in the cameras field of view such as walls and other objects and builds a 3D map of the area. A series of accelerometers and gyroscopes monitors the user’s location and speed to determine the wearer’s relative position in relation to the 3D map. The compiled data is then sent to a tactile feedback display that produces a constant 3D map in braille form (at a rate of ten maps per-second) the gives the user a way of ‘seeing’ their environment in real-time.

The IISR team in France is also looking to combine their system with software being developed by engineers at the University of Nevada that was initially used to tell robots how far they have travelled based on its sensors (accelerometer/gyroscope). Their system uses smartphones internal sensors along with available 2D in-door maps and synthetic speech (SIRI?) to help the blind navigate. In order for the system to be effective, the phone must be calibrated to the users stride. This is done touching a series of stationary markers such as walls, hallway entrances and other obstacles. Both systems combined would greatly benefit the user’s ability to navigate just about anywhere in an urban environment. As to when this system/s will become readily available is anyone’s guess but then again ‘seeing is believing’.

It seems the scientific community is bent on technology returning sight to the blind. Read about more efforts in the area after this link.

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(Left) Implant behind eye. (Right) Retinal scan showing the sensor chip in place. (via University of Oxford)

Diagnosed with retinitis pigmentosa, the first symptom was night blindness. A few years later, vision was drastically reduced. Finally, another disease brought complete blindness in the left eye and the inability to distinguish light on the right. Chris James, a fifty-four year old council worker in Wiltshire U.K., had his life completely changed by his complications. He said, "It’s something you have to come to terms with and make the best of what you’ve got."

Chris James's new eye was switched on for the first time. The digital circuits flood with electricity. James could see light against a black background for the first time in decades. The retinal implants were a success. "As soon as I had this flash in my eye, this confirmed that my optic nerves are functioning properly which is a really promising sign. It was like someone taking a photo with a flashbulb, a pulsating light, I recognized it instantly."

Chris James was one of the first patients (along with Robin Millar, a 60 year old music producer) suffering from retinitis pigmentosa to receive retinal implanted circuitry to detect light and images from a collaboration between the University of Oxford (UO) and the company "Retina Implants" form Germany. A team led by ophthalmology professor Robert MacLaren were able to help the patients regain some semblance of vision. As the patients continue to use the implants, their vision continues to improve. Currently, the patients can see light differences and basic shapes.

X-ray image of the complete system installed into Chris James. (via University of Oxford)

The implant is a 3mm square chip containing 1,500 light sensitive diodes. The chip is attached to the back of the eye where a signal can be sent between electrodes and the patient's optical nerves. The system is powered by an implanted power supply buried behind the ear, similar to some cochlear devices. Professor MacLaren explained that the sensor will "stimulate the overlying nerves to create a pixellated image." He continued, "Apart from a hearing aid like device behind the ear, you would not know a patient had one implanted.  We are all delighted with these initial results. The vision is different to normal , and it requires a different type of brain processing. We hope, however, that the electronic chips will provide independence for many people who are blind from retinitis pigmentosa."

The U.K based trials will continue with 12 patients overall thanks to funding from the National Institute of Health Research and the Oxford Biomedical Research Centre.

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Cochlear implant concept (via University of Utah)

Cochlear implants have improved the hearing for over 220,000 deaf people around the globe, but they have their drawbacks. Not being able to swim or wear helmets comfortably due to the delicate microphone and related electronics worn on the outside of the ear are just some of the tip of the limitation. A team of engineers, led by Associate Professor Darrin Young from the University of Utah, are looking to fix those issues by implanting the cochlear microphone inside the ear itself, giving the user an increased level of freedom in otherwise damaging environments.

Typical implants house the microphone, signal processor and transmitter coil in a plastic shroud worn behind the ear. The mic picks up sound and sends it to an internal receiver-stimulator attached to bone under the skin by the microphone housing. From there, sound is sent to electrodes attached to cochlea which in-turn stimulates auditory nerves making it possible for the user to hear. Young’s design places all the external components normally worn outside the ear inside by placing an accelerometer sensor that’s attached to a chip on the ears umbo part of the tympanic membrane to detect vibration. This converts sound into electrical signals that are then sent to the electrodes attached to the cochlea which is powered by an implanted battery enabling the user to hear.

Recharging the battery is done at night while the user sleeps using a charger located behind the user’s ear in much the same fashion as wearing a typical cochlear implant. Successful testing was done using several cadavers (yes, you read that right) implanted with the new cochlear system. A laser was then used to measure the vibration on bones inside the ear to see which one was more efficient at picking up normal-level sound after which it was found that the umbo was the most successful. In order to test this device, the implanted microphone was wired to speakers with Beethoven’s Ninth Symphony acting as the test medium. While the sound was ‘muffled,’ Young states that ‘the muffling can be filtered out’. The team hopes to improve the overall sound quality in future versions so clinical trials are still a few years away but anything that can assist the disabled is still a hopeful future.

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