BACKGROUND: Ultrasound is an established method of viewing the median nerve in 
the carpal tunnel syndrome (CTS). There is some evidence to suggest that 
immediate changes may occur in the median nerve before and after hand activity. 
The evidence for the validity and reliability of ultrasound for testing acute 
changes in the median nerve has not been systematically reviewed to date.
AIMS: To evaluate the evidence for visible change in ultrasound appearance of 
the median nerve after hand activity.
METHODS: A literature search was designed, and three reviewers independently 
selected published research for inclusion. Two reviewers independently appraised 
papers using the Evidence Based Library and Information Practice (EBLIP) 
appraisal checklist, while the third reviewer resolved discrepancies between 
appraisals.
RESULTS: Ten studies were appraised and the results showed an increase in median 
nerve cross-sectional area following activity, with a return to normal size 
within 1 h following activity. Both healthy individuals and those diagnosed with 
CTS participated, all were small convenience samples. Ultrasonographic 
measurements of the median nerve were reliable in the four studies reporting 
this, and the studies demonstrated high quality.
CONCLUSIONS: Good-quality evidence as identified by the EBLIP appraisal 
checklist suggests that following hand activity, the median nerve changes in 
size in the carpal tunnel. The results may not be generalizable to all people 
and activities due to the use of small convenience sampling and narrow range of 
activities studied, in all of the studies appraised.