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Updated: Dec 31, 2025
Screening of Axonal Degeneration in Carpal Tunnel Syndrome Using Ultrasonography and Nerve Conduction Studies
Published on: January 11, 2019
Impact of technical variations on the ring-finger test for carpal tunnel syndrome
Daniel Gregor Schulze1,2,3, Karl-Christian Nordby4, Milada Cvancarova Småstuen5,6
1Department of Neurology, Oslo University Hospital, Oslo, Norway.
Objective:
To assess if recording the sensory latencies of the median and ulnar nerves one-by-one (consecutive) or at the same time (simultaneous) in the ring-finger test for carpal tunnel syndrome (CTS) will show equivalent results or if it will lead to a different clinical classification of patients.
Methods:
We assessed the limits of agreement between the simultaneous and the consecutive method based on the median- ulnar sensory latency difference derived by both methods in 80 subjects and compared the number of minimal CTS cases identified by the two methods.
Results:
Limits of agreement ranged from -0.23 to 0.29 ms. A significantly higher proportion of subjects with minimal CTS (only detectable by using the comparison test) was found using the simultaneous method (n = 8 and 2, respectively; p = 0.03).
Conclusion:
The two methods have a poor to moderate agreement as indicated by the range of the limits of agreement (0.5 ms).
Significance:
Even small methodological changes to the ring-finger test can lead to results with different clinical meaning in the same individual and one should be aware of which method was used when interpreting results.
