Neural Prostheses 2 Flashcards
What are neuroprostheses (NPs)? What is this approach called?
- electronic devices that stimulate nerves to improve bodily functions lost as a result of PNS or CNS damage
- this approach is called FES or FNS
What are the basic components of FES?
- power supplies (external or implanted)
- control circuit
- lead wires, connectors
- electrodes
- sensors
Electrodes act as a _____________, delivering electrical charge from a power supply to the tissue
conductor
When does charge transfer occur?
when voltage applied between active and reference electrodes generates an ELECTRIC FIELD, in turn forcing electrical charge to flow
TRUE or FALSE: stimulation to the nerves requires much larger charge densities than to muscle fibers
FALSE: SMALLER charge densities
What is the advantage of implanted FES devices?
targeted application with SMALLER CURRENT DENSITIES used
What are some conditions that may benefit from neuroptostheses?
- hearing loss due to damaged inner ear
- SCI
- stroke
TRUE or FALSE: SCI affects mostly young and older adults, usually male
TRUE
In FES for upper extremity functional restoration, muscle contractions can be orchestrated to produce what 3 motor actions?
- handgrip
- hold and release cylinder
- lateral gripping for thin objects
To maximize function, what can FES for upper extremity functional restoration be coupled with?
tendon transfer surgery
What are some examples of surface stimulation devices for FES for upper extremity functional restoration?
- bionic glove
- myndmove
What is an example of an implanted device for FES for upper extremity functional restoration?
the freehand system
where are surface electrodes placed in the bionic glove?
hand and forearm
How does the bionic glove work?
- stimulation triggered by movements, which are detected by a sensor
- extension of handle –> gripping
- flexion –> opening of hand
How does the Freehand system work? What level of injury is it used for?
- stimulator implanted in chest wall, connected to electrodes implanted on the motor points of the arm and hand muscles
- C5 complete injury
- contralateral shoulder motion causes hand opening and closing
TRUE or FALSE: the freehand system is still in the market
FALSE
How does the MyndMove work?
- multi-channel system using ONE stimulator
- surface electrodes along the upper extremity can generate complex function movements
Surface neuroprostheses that enhance _____ may be helpful to persons with SCI with a ___________ by causing ankle ________________ when sensors are triggered.
gait; foot-drop; dorsi-flexion
What are some examples of FES for lower extremity functional restoration to enhance gait?
- Bioness L300
- Walkaide
What are some examples of FES for lower extremity functional restoration to enable exercise training?
FES cycling
For FES for lower extremity functional restoration, IMPLANTED neuroprostheses may be useful for persons with ________ level SCI, with _____________ ________________ of the lower extremity muscels enabling ___________ and __________.
thoracic, stimulated contractions, standing, stepping
What can power the sit-to-stand transition and support the body vertically against collapse?
- 8+ channels of continuous stim to the knee, hip, and trunk extensors
What areas of the body should you use continuous stim on to assist in posture?
trunk and hips
What are 2 ways to achieve diaphragm contraction through neuroprostheses?
- phrenic nerve stim
- directly stimulate the motor points in the diaphragm
Does phrenic or diaphragmatic stimulation potentially cause direct nerve injury and have a longer recovery time?
phrenic
Stronger cough can be restored in persons with ___________ and ___________ level injuries through spinal cord stim with surgically implanted electrodes between ___ and ___.
cervical; thoracic; T9, T11
Implanted neuroprostheses have been developed to provide stimulation to ____________ nerve roots in order to control bladder contraction
sacral
TRUE or FALSE: bladder after SCI involves loss of excitatory control
FALSE: loss of inhibitory control
What is the main approach for bladder control restoration? What is the main drawback?
- sacral anterior root stimulator implant (SARSI)
- drawback: dorsal rhizotomy to decrease sensory afferent to the spinal cord
What kind of stim can be used for gait restoration?
intraspinal microstimulation (ISMS)
Describe intraspinal microstimulation (ISMS). WHere is it implanted? How does it work?
- implant ultrafine microwires into the anterior horn of the lumbar enlargement
- single electrode stimulates a synergistic group of muscles
What animal model has been used to test ISMS?
cat model
What is the main method used to restore autonomic cardiovascular function after SCI?
transcutaneous stim over spinal cord to restore blood pressure
What is the main method used to prevent pressure injuries after SCI? What is an example of a device that can do this?
- surface and implanted stim
- Smart-e-pants
How do the Smart-e-pants work? What is its purpose?
- purpose: pressure injury prevention
- intermittent electrical stim (IES) of the GLUTEUS MAXIMUS through SURFACE STIM
- this redistributes pressure, improves tissue oxygen, and reduces deformation of muscle tissues
