This interactive discussion will focus on cases of carpal tunnel syndrome that are difficult to resolve by nerve conduction study (NCS) and EMG techniques, and will include the use of ultrasound in CTS evaluation. The cases will include re-evaluation of symptomatic patients who have had carpal tunnel relief in the past. Assessment of very mild CTS and its differentiation from early polyneuropathy will also be discussed. Very severe cases of median nerve injury will be presented and will include special NCS techniques helpful in understanding the nerve’s function. There will be demonstrations of some NCS and ultrasound techniques in order to clarify their use, as well as demonstrations of testing for conduction block in motor and sensory fibers to verify sites of nerve compression. The usefulness of severity grading in CTS as well as the use of the Robinson CSI methods will also be reviewed. Attendees are encouraged to bring their questions as well as difficult cases for interactive discussions in large or small group sessions.