I know that surface electromyography (sEMG) is used by doctors and
chiropractors to measure muscle activity, but I'm looking for a
comprehensive list of specific applications it is (or could be) used
for, both in research and in practice.

For example, the DelSys website (http://www.delsys.com) cites uses
such as muscle strength assessment, but I'd like more specific
information (i.e. what conditions are treated, what muscles, efficacy,
etc.).

Please do not include any information about standard (invasive)
electromyography, in which needles are inserted into the muscles.

Hello ab64:

Thanks for the fascinating question. I have looked high and low on the
Web and compiled the following list of uses for sEMG. I have broken
down my findings into "Current Uses" and "Research Areas", depending
on the context of the sources where the use was found. Many of the
listed uses are not in good standing by some medical
boards/associations at this time.


Current Uses: 

* Used by physical therapists to address movement disorders including
tremor, dystonia, myoclonus and central gait disturbances
* Psychologists employ sEMG to intervene with problems attributed to
excessive psychophysiological arousal.
* Occupational therapists incorporate sEMG into functional job analyses. 
* Rehabilitation nurses and therapists treat incontinence related to
dysfunction of the pelvic floor muscles with sEMG feedback.
* Physiatrists, orthopedists, and neurologists may be interested in
sEMG procedures to enhance diagnosis of movement disorders as well as
monitor the effects of medicines and surgical interventions designed
to impact muscle activity.
* Physical medicine and rehabilitation clinicians may increase the
sophistication of patient evaluations through quantification of muscle
activity.
* Used for the diagnosis or monitoring of nocturnal bruxism
* Used as a diagnostic test for the evaluation of back pain or other
thoracolumbar segmental abnormalities (e.g., soft tissue injury,
intravertebral disc disease, nerve root irritation and scoliosis)
* Used in jaw muscle tracking 
* Can be used as one part of a full assessment protocol to determine
if a patient has significant muscle asymmetries, problems with
guarding, possible postural disturbances, and significant muscle
fatigue.
 

Research Areas:

* Investigation of movement control and psychophysiological phenomena
* Study of the effects of orthotics, manual therapies, and therapeutic exercises.  
* In children - address the functional changes desired as a result of
therapy, specifically, standing balance training, treadmill gait
modification, reciprocal crawling, minimax sitting modification, and
tonic muscle activation.
* Tendon transfers are performed to improve function in peripheral
nerve injury, brachial plexus lesion, spinal cord injury, and cerebral
palsy
* Preoperatively choosing the muscle for transfer has been largely
based on clinical grounds. Multichannel surface EMG could give a more
objective database to assess prognosis and determine which muscle to
transfer.
* Multichannel surface EMG can provide a systematic way of assessing
changes in gross muscle topography caused by the tendon transfer
* Other applications of multichannel surface EMG would be for bony and
soft tissue deformity from arthritis, heterotopic ossification,
amputation, or burns
* Multichannel surface EMG would allow clinicians to get a broader
picture of the skeletal muscle activity despite the fact that it is
physically impossible for the patient to assume the anatomic position
used for traditional isolated electrode placement.
* Individuals with physical disabilities that affect their ability to
assume the usual posture for electrophysiologic testing may benefit
considerably from development of multichannel electrophysiologic
testing.
* The diagnosis of myofascial pain problems.


Sources

Using Surface Electromyography
URL: http://www.rehabpub.com/ltrehab/12002/5.asp

Surface Electromyography (SEMG) and Spinoscopy
URL: http://medpolicy.unicare.com/policies%5CMED%5CSEMG.html

SEMG/SESNA Section 
URL: http://www.aapb.org/i4a/pages/index.cfm?pageid=3574#CurrentResearch

WHAT IF THE BITE IS NOT RIGHT?
URL: http://www.dentalorthotic.com/client_QandA.cfm

Anatomical and technical considerations in surface electromyography.
URL: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9894103&dopt=Abstract

Search Strategy (on Google):
* "surface electromyography" 
* "surface electromyography" uses 
* "surface electromyography" bruxism tremor 
* SESNA SEMG
* "surface electromyography uses" OR "uses of surface electromyography"

I hope this helps. Please let me know if you need further
clarification before you rate this answer.

websearcher

Hi Websearcher,
Thanks very much for your fast and thorough response!