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Sorry for the prolonged delay in posting the summary - we are still
working out some of the bugs but are moving forward. Thanks to those
that responded to the original posting which was:
I have been in contact with Biopac about obtaining equipment for testing
the H-reflex in the lower extremity but was informed that I would be
best served by obtaining electrodes for applying the stimulus from
another supplier. So I was wondering what is working for those testing
this reflex and what recommendations could be made. We have electrodes
that we are happy with for the EMG recording but would like to get a
consensus (if possible) on which electrodes work best of the actual
stimulation.
Here are the responses I received:
I've been using the biopac AG-AGCL 8MM TP ELECT., UNSHLD - EL258 -
http://www.biopac.com/Research.asp?Pid=3587
for years. I've tried
other companies - but find the best results with these. I do modify
them. They are too deep - so I file down the surface of the plastic
cover over the electrode surface until it will hold just enough gel. I
then place the electrode face down on a counter, and use a hot glue gun
to slowly surround the back and sides of the electrode, allowing it to
flow in a circle around the sides. This increases the diameter of the
surface surrounding the electrode and gives me a place to adhere the
adhesive disks on the front
(http://www.biopac.com/Research.asp?Pid=3579&Main=Electrodes
) I am
careful around the wire and not to allow the electrode to get too hot.
I find this works great. I do several at a time and use one until it
fails - they usually last for months depending on the care and frequency
of use. I clean them after each use with hydrogen peroxide.
Hope this makes sense - I'd be happy to send a picture if that would
help. Good luck with your work!
JoEllen M. Sefton, PhD, ATC, CMT
I used self-adhesive, pre-gelled baby EKG electrodes to elicit
H-reflexes with the femoral nerve. They worked well for me, are not
extensive and easy to apply. I'd find the femoral nerve by first
palpating the femoral artery in the femoral triangle. I'd then probe
that area with a conventional galvanic stimulator probe, mark the skin
and then apply the EKG electrodes.
Andy McDonough
We have been using carbon electrodes from Medi-Stim (details below) that
we have been very satisfied with. All you need is some gel from either
Grass or some other stimulation gel.
Medi-Stim Inc.
217 Industrial Court
Wabasha, MN 55981
Ph: (800) 363-7846
Fax: (651) 565-2410
sales@medi-stim.com
Shane Esau
I do not use EMG electrodes for stimulating. For the cathode over the
posterior tibial nerve I use a home-made electrode that is a small block
of Plexiglas. The advantage of the "block" is that with the thickness
of the electrode block, the tape or elastic wrap holding the electrode
in place can firmly push the electrode surface against the skin, and the
underlying nerve, in the fossa even when the knee is slightly bent and
the hamstring distal tendons are sticking out to create a rim on the
sides of the fossa. The block has a 10 mm in diameter socket on the
side against the skin, the socket is filled with a felt that is soaked
in saline and protrudes slightly from the surface of the block. The
electrode wire connects to a metal ring that lines the inside of the
socket, and so connects the lead wire to the wet felt.
A 36-cm2 metal plate anode electrode is attached to the thigh just
proximal to the patella.
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Gordon Chalmers,
I use Biopac self-adhesive electrodes. I believe the code and number is
EL503. I shave and abride the area prior to application and they do
more than adequate job with recordings. Hope this helps.
Brad Hayes
Again, thanks to those that responded to the original posting.
Clark Dickin