View Full Version : double crush and electrodiagnostic testing

06-25-1996, 05:54 AM

I am a PhD student and physical therapist and have been attempting to
collect pilot data for my dissertation. My interest is in the 'double crush
phenomenon' first described by Upton and McComas in 1973. I would like to
further investigate this multi-site nerve entrapment phenomenon in humans
relating carpal tunnel syndrome to proximal compression. Specifically, I
will be looking at a variety of tests to stress the carpal tunnel region and
thoracic outlet (inlet) region simultaneously.

My interest would be to stimulate evoked potentials at the finger (ring
electrodes) or palm and utilize surface electrodes to record at the wrist,
elbow, and supraclavicular region (Erb's point) and determine latency and
amplitude changes. Thus far, I have had great difficulty with the more
proximal recording sites. I realize that the signal will attenuate as I go
proximally and probably require the implementation of averaging techniques.

I am asking for any detailed references, clinical advice, or list serve
groups regarding actual collection techniques. Otherwise names of
practioners I could contact who have been doing thoracic outlet testing
would be appreciated. I feel I have done a great deal of searching in the
literature, but am now having difficulty practically applying the
techniques. Most of the studies I have reviewed do not detail the techniques
enough to help once questions / difficulties arise. References such as
Kimura's text have been helpful.

Suggestions thus far have included the use of needle electrodes, attempting
to assess SSEPs, increasing pulse width, and averaging.

I look forward to any advice

Thank you and have a great day.

Kevin P. Farrell, MA, PT, OCS
Assistant Professor
Physical Therapy
St. Ambrose University
518 W. Locust St.
Davenport, IA 52807
319-333-6405 (office)
319-333-6410 (FAX)