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Gabor Barton
06-10-1997, 07:57 AM
Dear readers,

On 21/5/97 I posted the following message to the list:

>In our gait lab as a part of clinical gait analysis I record surface
>EMG of children between ages of 5 to 18. I have difficulties finding
>the best disposable self-adhesive passive surface electrodes. I tried
>small electrodes but they don't adhere well having only a narrow
>adhesive collar. The larger electrodes stick well, but the inter-
>electrode distance is too much (46mm) which increases cross talk.
>Could you please share your experience with me, if you have any
>contact addresses of manufacturers in the UK I would be grateful.
>Thanks for your help, please reply to my email address, I will post a
>summary.
>
>Dr. Gabor Barton
>Manager, Gait Analysis Laboratory
>Alder Hey Children's Hospital
>Liverpool, UK

My email has changed in the meantime, sorry if you can't find your
reply. Thanks for your help, as promised here are the replies:

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I have had very little experience with EMG, but have been doing some
pilot testing using EOG techniques. Before I had the chance to get
some neonatal electrodes, which I assume are the small electrodes
that you have tried, but keep falling off, we would use the "regular"
size electrode, but trim the edges so it would fit better. Maybe
this would work for you.

Jan M. Hondzinski
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Our gait lab has had the same problem with our EMG electrodes. We
use two different products that both seem to work quite well. We use
electrodes that have a snap attatchment on them. The products that
we use are: BioTac Jr. pediatric ECG electodes by Graphic Control
(these electrodes are rectangular) or the Sentry Hydro-Snap ECG cloth
electrodes by Sentry Medical Products (these electrodes are
circular). The inter-electrode distance between the BioTac Jr is
~20mm. We cut one side of the Sentry products so that the electrode
is not circular. We then put the flat sides next to one another.
This creates an inter electrode distance of ~12 mm. I think that a
lot of round electrodes can be cut, thus making the inter electrode
distance smaller. The Hydro_snaps are about 1/3 the price of the
BioTac ($0.11 CDN vs. $0.30 CDN per electrode)

Sentry Hydro-Snap order #1093
Sentry Medical Products
331 S.Eisenhower Lane
Lombard, IL 60148

BioTac Jr. order #6163
Graphic Controls Corp.

Alec Black
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We use a solid gel snap electrode made by uni-patch (612-565-2601).
We see the same age population as you and have had great success with
these electrodes. They use a 2cm X 3cm active area and stick to skin
well. When removed, children do not complain of pain or redness.
Removal of the electrode does not leave any gel residue or adhesive
on skin. Feel free to email or call with additional questions.

Patrick W. C
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I conduct research in gait analysis and have been using the
disposable Medi-trace pellet electrodes (part no. ECE 1801),
manufactured by Graphic Controls Canada for several years. Inter-
electrode distance is 2.5 cm (measured from centre to centre). I have
not had any problems with adherence to the skin. To prep the skin, I
just wipe the area with alcohol and wait until it dries before
placing the electrodes.

The address for the company is:

Graphic Controls Canada Ltd 215 Herbert Street Gananoque, Ontario
Canada K7G 2Y7

Sharon Walt
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My best experiences have been with electrodes from Medicotest in
Denmark. They have a range of both pre-gelled and dry electrodes.
The ones to go for are the paediatric EKG electrodes.

Paediatric EKG electrodes from other manufacturers also work, and you
can get the spacing down by judicious trimming of the adhesive
collar, but then, extra tape over the top is usually in order.

Owen Evans
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We have used the 3M paediatric Red Dot electrodes with either the
foam self stick collar or the "gauze" type collar. Trim off one side
so that interelectrode distance can be minimized but allow enough so
that some adhesion occurs on that side as well as the neighbouring
electrode being able to stick to some of the collar of its neighbour.
Just make sure that none of the gel squezzes out to allow conduct
between electrodes. Have used these procedures with the branched
electrode configuration as well and appears to work okay.

Peter Hamer
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We get our electrodes from a company called Southern syringe
Services, based in Eccles, Manchester. They are distributers for 3M.

Tracey Howe
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use standard commercial meditrace electrodes but cut the edges away
so that each electrode is a little more than a semicircle this will
get the interelectrode distance below 20mm while still giving you a
good adhesion.

James Wickham
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We recommend using Bio-Tabs self adhesive pre-gelled electrodes.
These are quickly and easily attached with minimum skin preparation.
Furthermore, you can cut them down to any size you want. However,
they smaller they are, the more critical skin resistance becomes.

Dr. Malcolm Ellis
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H-59P infant electrodes from:

Henleys Medical Supplies Brownfields Welwyn Garden City Herts. WL7
1AN

Tel. 01707 333164

may solve your problem of finding passive Ag-AgCl surface electrodes
for use with small muscles, and which have good adhesive properties.
They are 1 cm dia. and, if the surrounding adhesive patches are
placed next to each other, have an interelectrode distance of 2 cm. I
have used them with the MEGA ME3000P system, and am very pleased with
the EMGs.

Adrian M. Burden
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My experience with surface electrodes has led me to use Medicotest
blue sensor electrodes almost extensively with studies on athletes(I
think thay are E-50 type), and have experienced few problems with the
electrodes themselves. I hope this helps

Neal Smith
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================================================== ==================
\ Dr. Gabor Barton MD \ G.Barton@gaitlab.demon.co.uk \
\ Manager, Gait Analysis Laboratory \ tel: +44 (0)151 252 5949 \
\ Alder Hey Children's Hospital \ fax: +44 (0)151 252 5846 \
\ Eaton Road, Liverpool, L12 2AP, UK \ \
================================================== ==================

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