During the Upper Limb Neurodynamic Test 1 (ULNT1) joint movement order can be varied to improve its diagnostic accuracy. However, nerve behavior with neurodynamic sequences still requires in vivo research. To quantify differences in median nerve (MN) stiffness measuring shear-wave velocity (SWV) with ultrasound elastography during three sequences of the ULNT1. Cross-sectional study. MN SWV was measured in 35 asymptomatic subjects at the wrist and elbow at the initial and final position (P1) of the standard (ULNT1-STD), proximal-to-distal (ULNT1-PROX) and distal-to-proximal (ULNT1-DIST) sequences of the ULNT1. Significantly different increases at P1 in nerve stiffness occurred between sequences and locations (p < 0.001). At the wrist, the ULNT1-PROX produced the smallest increase (44.32% ± 44.06, SWV: 4.49 ± 0.95 m/s), the ULNT1-STD produced a larger increase (82.13% ± 45.36, SWV: 5.67 ± 0.79 m/s, p < 0.001) and the ULNT1-DIST produced the largest (92.90% ± 55.37, SWV: 5.97 ± 0.79 m/s, p < 0.001). Differences between the ULNT1-DIST and ULNT1-STD did not reach significance. At the elbow, the ULNT1-PROX showed a 119.92% ± 53.51 increase (SWV: 4.08 ± 0.84 m/s), the ULNT1-DIST a 134.84% ± 53.83 (SWV: 4.34 ± 0.77 m/s), and the ULNT1-STD a 113.30% ± 59.28 (SWV: 3.98 ± 1.04 m/s). No significant differences were found among the sequences. The ULNT1-STD and ULNT1-DIST showed greater increases at MN stiffness at the wrist compared to the ULNT1-PROX. This supports a basis for future investigation of the mechanisms of neurodynamic testing in which emphasizing anatomical locations for improving diagnostic efficacy might be applied.

Background/Objective: This study aimed to evaluate the diagnostic accuracy of two upper limb neurodynamic test 1 (ULNT1) sequences for detecting carpal tunnel syndrome (CTS) in patients with unilateral symptoms. The standard sequence (ULNT1-STD) and a distal-to-proximal sequence (ULNT1-DIST) were investigated. A local-initiated sequence may facilitate symptoms reproduction in CTS, and comparing the affected side with the unaffected side could improve the detection of altered median nerve mechanosensitivity when symptoms are not directly reproduced. Methods: A total of 134 consecutive patients with clinically suspected unilateral CTS were recruited. Nerve conduction studies were used as a reference test. Results: When considering only symptom reproduction as the criterion for a positive test, ULNT1-STD showed a sensitivity of 0.398 and a specificity of 0.780 (positive likelihood ratio [+LR]: 1.81; negative likelihood ratio [−LR]: 0.77); whereas ULNT1-DIST demonstrated a sensitivity of 0.548 with a specificity of 0.732 (+LR: 2.04; −LR: 0.62). When a positive test was defined by symptom reproduction or inter-limb asymmetry (in range of motion or sensory response), ULNT1-STD showed an improved sensitivity of 0.613 but a reduced specificity of 0.537 (+LR: 1.32; −LR: 0.72). In comparison, ULNT1-DIST increased its sensitivity to 0.871 with a specificity of 0.683 (+LR: 2.75; −LR: 0.19). Conclusions: ULNT1-DIST offers better diagnostic accuracy for CTS compared to the ULNT1-STD sequence, especially when interlimb asymmetries in range of motion or sensory response are considered. However, side-to-side comparisons have reduced utility in cases with bilateral symptoms, limiting their application in clinical practice.