Background: The median-to-ulnar comparison test (MUCT), and
increasingly, ultrasonography (US) are considered as
complementary to and more sensitive than median nerve conduction
study (NCS) in diagnosing carpal tunnel syndrome (CTS).
Methods: In consecutive patients with hand paresthesia compatible
with CTS but with normal median NCS, we additionally performed
the MUCT and analyzed whether it yielded better diagnostic
sensitivity.

Results: In total, 163 hands of clinically diagnosed CTS patients
were examined with routine NCS. The MUCT and US were performed in
81 hands and 31 hands, respectively. While median NCS was
diagnostic in 85 (52.1%) hands, MUCT failed to demonstrate
superior sensitivity over median NCS in the other hands and US
revealed related abnormalities better than both routine NCS
(p=0.006) and MUCT (p=0.002).

Conclusions: The MUCT offered no additional diagnostic benefit.
On the other hand, sonographic examination had higher sensitivity
for the diagnosis of CTS when applying several diagnostic
criteria.
Thus, US could be the screening test for diagnosing CTS prior to
NCS with higher sensitivity than MUCT. However, further studies
are needed to define the appropriate diagnostic criteria for US.

KEYWORDS : Carpal tunnel syndrome, Comparative study, Ultrasonography, Electromyography