u sing emg signal to improve prosthesis control carolyn carr
Post on 17-Jan-2016
229 Views
Preview:
TRANSCRIPT
USING EMG SIGNAL TO IMPROVE PROSTHESIS
CONTROLCarolyn Carr
INTRODUCTION
Kuiken, T. et al, (2004) The use of targeted muscle reinnervation for improved myoelectric prothesis control in a bilateral shoulder disarticulation Amputee
INTRODUCTION
Control of disarticulation shoulder
prostheses Elbow, wrist, and hand Externally controlled
One function at a time myoelectric signal or body powered Locks need to be done sequentially
INTRODUCTION
Brachial plexus Function
Upperlimb muscular innervation Cutaneious
Amputation of the arm the “control information” for the
arm is still in the Brachial Plexus Relocate the nerves
Use the nerve muscle units for control
INTRODUCTION
Difficulties: After transecting nerves do not reinnervate their
own muscles consistently Controlling the independent nerve-muscle units
Beneifts: Myoelectric control
Motorneutrons transfer onto small amounts of muscle Hyper-reinnervate
Hyper-reinnervate Improves muscle recovery Full muscle recovery possible
INTRODUCTION
Purpose of this study is to use nerve
transfers to improve control of the prosthesis
using myoelectric control sites.
METHODS
Subject 54 year old white male Bilateral shoulder disarticulation amputations
Right side Body powered prothesis Voluntary opening split hook Four function unit
3 mechanical chin switches Elbow, wrist, and shoulder
Left side to be replaced Externally powered prosthesis Use the muscles as a biological amplifier for
independent signals
METHODS
Reason for surgery Good shoulder motion Strong pectoralis muscle contraction No sign of brachial plexopathy
Benefits Significant improvement in the left prosthesis
If failed Still able to use what he was already using, touch
pad control
METHODS
Surgery Brachial Plexus identified Muscles in chest subdivided into individual units
based on muscle innervations and vascularity Brachial plexus nerves mobilized down to the
muscle segments
METHODS
Surgery details: Pectoralis major was divided into three parts
The clavicular head Lateral pactoral nerve, upper and lower segements. Sternal Head
upper segments lower segments
The pectoralis minor moved Moved laterally to the mid-axillary line
Prevent EMG-Cross talk To Improve EMG signal, subcutaneious fat was
surgically removed
METHODS
Recovery Physical therapy
The patient was told to open and close hand on daily basis
5 months active muscle contraction in different areas of the muscle
METHODS
How to operate EMG signal held for 1-2 seconds causes elbow
lock Higher EMG signal to release
Median area, controls open/close of hand Due to the two signals in Mid-pectoral, there were
more options for wrist rotation A touch pad A strong contraction of open/close would switch the
unit to pronation and supination a strong contraction to switch back, again,
METHODS
Testing Box and Blocks test (Mathiowetx et al, 1985)
1 inch square blocks moved to another box, with an obstacle of a short wall in between box
Modified, to test patient in a two minute time frame Clothes pins
On a horizontal bar, rotation pin and move to high vertical bar
Used three pins
METHODS
EMG Programming, Three strongest signals used for control Signal under clavicle (large signal)
musculocutaneious nerve
Flexing elbow Mid-pectoral region, two independent signals
Median Nerve Lateral, closing hand Medial opening hand
Method
Inferior pectoral region Radial Nerve
Extended elbowopen hand extend the wrist
Weak signal and difficult signal to isolate
RESULTS
3 out of 4 nerves were successful musculocutaneous nerve the median nerve the radial nerve
Ulnar nerve to pectoralis minor nerve anastomosis No visible or EMG signal detected on the later
pectoral region, where it was moved
RESULTS
Touch Pad Control Number
of Blocks
Myoelectric control Number
of blocks
Trial 1 5 10
Trial 2 5 14
Trial 3 7 18
Average 5.7 14
Box and Block Test Results
RESULTS
Touch pad control Time (sec)
Myoelectric control Time (sec)
Trial 1 153 83
Trial 2 137 122
Trial 3 121 99
Average 137 101
Clothes Pin Results
DISCUSSION
Three anatomical principles1. Brachial plexus differentiates into the median,
ulnar, musculocutaneous and radial nerves in mid-clavicle region
Important for individual control
2. The length of the distal brachial plexus and the terminal nerve were long enough to mobilize to the chest wall, without further grafting
3. Pectoralis muscles was sub-divided into three parts
If there where any overlap of the reinnervation, the EMG signals would have been comprimised.
DISCUSSION
Musculocutaneous nerve: Successful Largest EMG signal, may be due to the proximity
of the clavicle. Clavicle acted as an “electrical insulator”
Median Nerve: Successful 2 different signals: Hand closing, hand opening
Reinnervation of the abductor pollicis brevis Future studies should look into separating these out
DISCUSSION
Radial Nerve: Weak Visibly and tangibly successful Not independent of other signals, and weak Electrocardiogram was large enough to interfere
with the EMG signal Subcutaneous fat removed
Ulnar nerve: Failed Reinnervation at the pactoralis minor
When moving the pactoralis minor lateral, the blood supply was compromised
Unexpected results Skin sensory
Due to removal of subcutaneous fat
DISCUSSION
Three independent signals Two degrees of freedom Faster control
All test results showed compared to previous prosthetic the movement was more natural, and easier to control
For the future Could apply to the shoulder movement Other levels of amputees
CONCLUSION
Peripheral nerves were relocated to the pectoralis major muscle in a disarticulation patient
Obtain simultaneous control, using EMG signal, for two degrees of freedom
Sensory reinnervation was obtained in the upper portion of the chest
THANK YOU Questions?
REFERENCES Kuiken, T., Dumanian, G., Lipschutz, R., Miller, L., & Stubblefield, K.
(2004). The use of targeted muscle reinnervation for improved myoelectric prosthesis control in a bilateral shoulder disarticulation amputee. Prosthetics And Orthotics International, 28(3), 245-253. Retrieved from MEDLINE with Full Text database.
Huang, H., Zhol, P., Guanglin, L, & Kuiken, T. (2009) Spatial Filtering Improves EMG Classification Accuracy Following Targeted Muscle Reinnervation. Biomedical Engineering, 37, 1849-1857. doi: 10.1007/s10439-009-9737-7
top related