Abstract
ObjectiveTo examine differences in somatosensory phenotypes of patients with positive and negative neurodynamic tests and compare these with healthy participants. DesignCase-control study. SettingUniversity department. ParticipantsPatients with electrodiagnostically confirmed carpal tunnel syndrome (CTS) (n=53) and people without CTS (n=26) participated in this study (N=79). Patients with CTS were subgrouped according to the results of the upper limb neurodynamic tests biasing the median nerve into patients with positive or negative neurodynamic tests. InterventionsNot applicable. Main Outcome MeasureAll participants underwent quantitative sensory testing in the median innervated territory of their hand. ResultsOnly 46% of patients with CTS had positive neurodynamic tests. No differences were identified between groups for pain thresholds (P>.247). However, patients with CTS had increased mechanical (P<.0001) and thermal detection thresholds (P<.0001) compared with people without CTS. Patients with negative neurodynamic tests had a more pronounced vibration detection deficit (mean, 7.43±0.59) than people without CTS (mean, 7.89±0.22; P=.001). Interestingly, warm detection was the only domain differentiating positive (mean, 4.03°C±2.18°C) and negative neurodynamic test groups (6.09°C±3.70°C, P=.032), with patients with negative neurodynamic tests demonstrating increased loss of function. ConclusionsPatients with negative neurodynamic tests seem to have a more severe dysfunction of the unmyelinated fiber population. Our findings suggest that neurodynamic tests should not be used in isolation to judge neural involvement. Rather, they should be interpreted in the context of loss of function tests of the small fiber domain.
Highlights
No differences were detected between groups for all scales (P>.08) except for the Pain Anxiety Symptom Scale and Depression and the positive outlook subscale of the Anxiety and Positive Outlook Scale, in which patients with carpal tunnel syndrome (CTS)
The duration of symptoms in the patient groups (PZ.311), the electrodiagnostic severity graded with the Bland scale (PZ.954),[30] the scores of the Boston questionnaire for both symptoms and function (P>.358), and the measures of neuropathic pain (Neuropathic Pain Symptom Inventory: PZ.[904], Leeds Assessment of Neuropathic Symptoms Scale: PZ.726) were comparable between the positive and negative upper limb neurodynamic tests (ULNTs) groups
We found a significant difference between groups for the cold and warm detection thresholds and thermal sensory limen testing and the vibration and mechanical detection thresholds (PZ.[001] and P
Summary
Fifty-three patients who met electrodiagnostic[17] and clinical[18] criteria for CTS were enrolled in the study. ULNTs were rated as positive if the patients’ current symptoms could be at least partially reproduced and if a structural differentiation (sensitizing movements at a site distant to the symptoms) was indicative of neural involvement[1,19] (eg, shoulder elevation relieves finger symptoms during ULNT 2a) This standardized performance is in accordance with recommended criteria for the execution and interpretation of ULNTs20 and has shown moderate intertester reliability.[19] Participants were familiarized with this test procedure on the nonexperimental arm before testing the experimental side. Sample size calculation based on previously published data of our cohort[16] revealed that at least 24 participants are needed per group to identify significant differences in detection thresholds among groups with 80% power and significance set at PZ.[05] (effect sizes, .36.56).g This sample size allows the detection of a 20% difference in pressure pain thresholds between groups, which is more sensitive than the reported clinically relevant difference of 36%.27
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
