Investigation of the relationship between invasive and non-invasive electrodiagnostic tests and performance based and patient reported outcome measures in patients with mild and moderate carpal tunnel syndrome

The purpose of this study was to compare the results of invasive and noninvasive electrodiagnostic tests in individuals with mild and moderate CTS and to examine the relationship between performance-based and patient reported outcome measures. Forty-one patients diagnosed with mild (n=20) and moderate (n=21) CTS were included in the study. Noninvasive electrodiagnostic methods included rheobase, chronaxy, and Strength-Duration Curve (SDC). Twenty-one stimulation times of 0-1000 ms were used to record the SDC. Motor function (thenar muscle strength, standard grip strength, and pinch strengths), sensory function (pain, paresthesia, joint position sense, vibration, static and dynamic two-point discrimination, light touch sensation, functional sense, cold intolerance), dexterity, functional level, and quality of life were evaluated. Sensory conduction velocity and distal motor latency values were recorded. The area under the curve was calculated for 0-10 ms (AUC0-10) and 0-1000 ms (AUC0- 1000), to determine cut-off values for mild and moderate KTS. The cut-off value was 96 for AUC0-10; and 132 for AUC0-1000. The sensitivity of AUC0-1000 was 76% and the specitivity was 50%. Between the two groups, there were differences in chronaxy, AUC, and position sense (p<0,05). The noninvasive electrodiagnostic tests moderately correlated with tripod strength, position sense, light touch in the mild CTS group and moderately correlated with light touch dynamic two-point discrimination (r=-0.521), functional sense, and dexterity (r=-0.534) in the moderate CTS group. There was a moderate correlation between chronaxie and distal motor latencies (r=0.433, p=0,007). Noninvasive electrodiagnostic tests are related with invasive electrodiagnostic tests, and motor and sensory nerve functions. Based on the results of these tests, clinicians can distinguish between patients with mild and moderate CTS