Neural Prostheses 2

Question 1

What are neuroprostheses (NPs)? What is this approach called?

Answer 1

• 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

Question 2

What are the basic components of FES?

Answer 2

• power supplies (external or implanted)
• control circuit
• lead wires, connectors
• electrodes
• sensors

Question 3

Electrodes act as a _____________, delivering electrical charge from a power supply to the tissue

Answer 3

conductor

Question 4

When does charge transfer occur?

Answer 4

when voltage applied between active and reference electrodes generates an ELECTRIC FIELD, in turn forcing electrical charge to flow

Question 5

TRUE or FALSE: stimulation to the nerves requires much larger charge densities than to muscle fibers

Answer 5

FALSE: SMALLER charge densities

Question 6

What is the advantage of implanted FES devices?

Answer 6

targeted application with SMALLER CURRENT DENSITIES used

Question 7

What are some conditions that may benefit from neuroptostheses?

Answer 7

• hearing loss due to damaged inner ear
• SCI
• stroke

Question 8

TRUE or FALSE: SCI affects mostly young and older adults, usually male

Answer 8

TRUE

Question 9

In FES for upper extremity functional restoration, muscle contractions can be orchestrated to produce what 3 motor actions?

Answer 9

1. handgrip
2. hold and release cylinder
3. lateral gripping for thin objects

Question 10

To maximize function, what can FES for upper extremity functional restoration be coupled with?

Answer 10

tendon transfer surgery

Question 11

What are some examples of surface stimulation devices for FES for upper extremity functional restoration?

Answer 11

• bionic glove
• myndmove

Question 12

What is an example of an implanted device for FES for upper extremity functional restoration?

Answer 12

the freehand system

Question 13

where are surface electrodes placed in the bionic glove?

Answer 13

hand and forearm

Question 14

How does the bionic glove work?

Answer 14

• stimulation triggered by movements, which are detected by a sensor
• extension of handle –> gripping
• flexion –> opening of hand

Question 15

How does the Freehand system work? What level of injury is it used for?

Answer 15

• 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

Question 16

TRUE or FALSE: the freehand system is still in the market

Answer 16

FALSE

Question 17

How does the MyndMove work?

Answer 17

• multi-channel system using ONE stimulator
• surface electrodes along the upper extremity can generate complex function movements

Question 18

Surface neuroprostheses that enhance _____ may be helpful to persons with SCI with a ___________ by causing ankle ________________ when sensors are triggered.

Answer 18

gait; foot-drop; dorsi-flexion

Question 19

What are some examples of FES for lower extremity functional restoration to enhance gait?

Answer 19

• Bioness L300
• Walkaide

Question 20

What are some examples of FES for lower extremity functional restoration to enable exercise training?

Answer 20

FES cycling

Question 21

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 __________.

Answer 21

thoracic, stimulated contractions, standing, stepping

Question 22

What can power the sit-to-stand transition and support the body vertically against collapse?

Answer 22

• 8+ channels of continuous stim to the knee, hip, and trunk extensors

Question 23

What areas of the body should you use continuous stim on to assist in posture?

Answer 23

trunk and hips

Question 24

What are 2 ways to achieve diaphragm contraction through neuroprostheses?

Answer 24

1. phrenic nerve stim
2. directly stimulate the motor points in the diaphragm

Question 25

Does phrenic or diaphragmatic stimulation potentially cause direct nerve injury and have a longer recovery time?

Answer 25

phrenic

Question 26

Stronger cough can be restored in persons with ___________ and ___________ level injuries through spinal cord stim with surgically implanted electrodes between ___ and ___.

Answer 26

cervical; thoracic; T9, T11

Question 27

Implanted neuroprostheses have been developed to provide stimulation to ____________ nerve roots in order to control bladder contraction

Answer 27

sacral

Question 28

TRUE or FALSE: bladder after SCI involves loss of excitatory control

Answer 28

FALSE: loss of inhibitory control

Question 29

What is the main approach for bladder control restoration? What is the main drawback?

Answer 29

- sacral anterior root stimulator implant (SARSI) - drawback: dorsal rhizotomy to decrease sensory afferent to the spinal cord

Question 30

What kind of stim can be used for gait restoration?

Answer 30

intraspinal microstimulation (ISMS)

Question 31

Describe intraspinal microstimulation (ISMS). WHere is it implanted? How does it work?

Answer 31

- implant ultrafine microwires into the anterior horn of the lumbar enlargement - single electrode stimulates a synergistic group of muscles

Question 32

What animal model has been used to test ISMS?

Answer 32

cat model

Question 33

What is the main method used to restore autonomic cardiovascular function after SCI?

Answer 33

transcutaneous stim over spinal cord to restore blood pressure

Question 34

What is the main method used to prevent pressure injuries after SCI? What is an example of a device that can do this?

Answer 34

- surface and implanted stim - Smart-e-pants

Question 35

How do the Smart-e-pants work? What is its purpose?

Answer 35

- 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