cp emg

mismmdkc at vaxd.dct.ac.uk mismmdkc at vaxd.dct.ac.uk
Wed Aug 17 00:15:34 EST 1994

Email mimmdkc at vaxd.dct.ac.uk

FROM: David Chadwick, University of Dundee/University of Abertay Dundee, 
Depts of Mechanical Engineering/A.P.E.M.E, MSc Mechatronics, Bell Street, 
Dundee, Scotland, DD1 1HG, Telephone 0382-308180 or 308000 
(Reference Professor John Milne or David Carus). 
Messages can be left with the Secretaries.

I am a MSc student at the above establishments and I am doing a project to 
help a young man with cerebral palsy. He is very seriously disabled and can 
only make small  movements of the head. The situation is complicated by a 
condition known as "spastic spasm" which can severely interrupt communication.
We decided to use the electromyogram (EMG) signals from the muscles of the 
face. One of the movements that he can do very well is to smile very broadly.
As from Friday 12th August I have succeeded in getting very strong EMG 
signals. In the morning, I went to the Dundee Royal Infirmary and asked a 
technician to connect the electrodes to my head. I then connected the other 
ends to my machine.
The system comprises:
	(a) an Amplifier that amplifies the signals 42,000 times.
	(b) an isolator that protects the person from shocks that might come 
	from the mains-driven computer or oscilloscope. The electrodes also 
	incorporate resistors that provide further protection even from low 
The signals are so strong that they can sometimes send the indicator off 
scale which is set at six volts. Therefore only slight pressure is needed on 
the muscles to cause a visible trace. It is also less tiring.
The person wears the electrodes on the face and operates the machine by 
twitching the facial muscles. I am getting strong signals from:
	(1) the eyebrow.
	(2) the cheek.
	(3) the jaw.
The cheek response is interesting because the patient can smile very nicely 
and only a slight twitch is needed.
The machine can be used to operate a computer with very little extra 
apparatus and a person with computer knowledge could design a customised 
system. It could, of course, be used on any other body muscle that works and 
could also be used in diagnosis.
For further information or an appointment to see a demo, contact me from the 
details given at the top of this report.

	DAVID K. CHADWICK   mimmdkc at vaxd.dct.ac.uk

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