Flashcards in Chapter 22 -Medical Technologies Deck (18):
Define Mobility Aids.
An aid designed to assist walking: includes walking sticks, crutches, walking frames, etc.
An artificial replacement for a part of the body; for example, an artificial arm or leg.
Refers to an artificial substitute that mimics the functions of a real body part.
What is Brain-machine interface?
-Research and development has focused on trying to find ways of converting brain activity into movements in the bionic limb.
-This is known as brain-machine interface - and it allows people to use thoughts to operate a machine .
Give an example of how does a Brain-machine interface work.
1. Surgeons relocated the nerves that would have been joined to the muscles in the left arm.
2. They attached those nerves to muscles in the chest.
3. Electrodes implanted in the chest muscles pick up any nerve impulses that are sent to the non-existent arm muscles.
4. A computer converts those nerve impulses into electric currents that operate small motors in the bionic arm and the motors bring about the desired arm movements.
List all the challenges that Artificial limbs experience.
1. Patients who do not have functional nerve endings.
2. Patients who have an injury to the spinal cord but still have functioning limb muscles.
3. The challenge to make prostheses feel and respond like normal limbs.
4. A future challenge is to collect the information on temperature and touch and send it, via nerves, to the brain of the person with the prosthetic skin.
Bionic limbs work well for patients who have existing nerve endings that are functional. But what if some patients do not have functional nerve endings?
-The challenge in these cases is to design prostheses that can be controlled by impulses directly from the brain.
-It is only a matter of time before such devices are developed.
What about patients who have an injury to the spinal cord, but still have functioning limb muscles?
Technology will make it possible to bypass the damage to the spinal cord with small electric currents that stimulate the limb muscles.
How is the challenge to make prostheses feel and respond like normal limbs overcome?
Synthetic skin has been developed that is flexible, elastic, tough and lightweight.
-It is also able to generate an electric current in response to touch or pressure.
-Technologists are now working on a version of the synthetic skin that can detect temperature as well.
What is the purpose of Artificial joints?
Joint replacement is used to treat diseased joints, especially those affected by arthritis.
What does Join Replacement involve?
1. The operation involves removing the diseased or damaged joint surface and part of the bone.
2. New joint surfaces are then implanted.
3. In some cases the bone grows into the implant to hold it in place; in others an adhesive is used to glue the implant to the bone.
4. Implants are made of metal, high density plastic or sometimes ceramics.
-> hips & knees are the most common joints to be replaced, but replacement of ankle, shoulder, elbow and finger joints is also possible.
What are the risks of Joint Replacement?
-It is a major surgery and there are risks both during and after the operation.
-risk of blood clots, reaction to the anaesthetic and infection.
-longer term: artificial joints can dislocate or become worn and loose.
What is the difference between a hearing aid and a cochlear implant?
1. A hearing aid increases the volume of sounds so that they are loud enough to be heard by an impaired ear.
2. A cochlear implant bypasses the damaged part of the ear by sending sound impulses directly to the auditory nerve.
Describe the process/structure of a cochlear implant.
1. During surgery an internal part, consisting of a receiver-stimulator, is placed under the skin behind the patient's ear and is connected to an array of electrodes implanted in the cochlea of the inner ear.
2. The external part, worn on the outside of the body, is a microphone to pick up voice sounds, a speech processor that turns the sounds into electrical signals and a transmitter that sends the signals to the internal device.
3. Sound reaching the speech processor is divided into its various frequencies and transmitted to the receiver-stimulator. From there the information on the sound frequencies is sent to the correct electrodes in the inner ear. The electrodes stimulate the auditory nerve which send the information to the brain.
What is the common misunderstand about cochlear implants?
-Is that they cure deafness.
1. At most a cochlear implant has 24 electrodes compared with the 16 000 sensory hair cells in an ear that is functioning normally.
2. Thus the device simply cannot produce anywhere near the quality of the sound a natural cochlea.
3. Some recipients can hear speech quite well while others are only able to tell the different between simple sounds.
4. However, for many people who have lost the ability to hear, the device provides a welcome improvement.
How are bionic eyes similar to bionic ears?
They both use electrical impulses to stimulate nerves that carry impulses to the brain.
How do bionic eyes work?
1. The patients wears a special pair of glasses that are fitted with a camera.
2. The image from the camera is sent to a processing unit that breaks it into pixels.
3. Using radio signals the pixels are sent, one at a time, to a silicon chip that is implanted in the eyeball in front of the retina.
4. The radio signals are then decoded and messages sent to the optic nerve through small wires.