Mechanosensitivity during straight leg raise and slump neurodynamic tests in people with type 1 diabetes mellitus and diabetic peripheral neuropathy.

Objectives: Neurodynamic tests are clinical tests used to identify heightened nerve mechanosensitivity but may be negative in the presence of severe neuropathy, as seen in people with carpal tunnel syndrome and type 2 diabetes. It is not known if this also occurs in people with diabetic peripheral neuropathy (DPN) from type 1 diabetes mellitus (T1DM). The primary aim of this study is to determine the proportion of positive neurodynamic tests in people with T1DM and DPN. The secondary aim is to assess whether the severity of DPN influences the presence of a positive neurodynamic test.

Methods: This is a cross-sectional study. Forty-three participants with T1DM and DPN were assessed using straight leg raise (SLR) and slump neurodynamic tests to determine a positive and negative test. DPN severity was graded according to Toronto Clinical Scoring System (TCSS).

Results: Forty-six percent and 56% of participants had positive SLR and slump tests, respectively, indicating heightened nerve mechanosensitivity. There was a statistically significant association between negative neurodynamic tests and DPN severity (p < 0.0001). In addition, participants with negative neurodynamic tests had significantly higher TCSS scores compared to participants with positive neurodynamic tests (p < 0.0001).

Discussion/conclusion: People with T1DM and severe DPN, as graded by TCSS, are more likely to demonstrate negative neurodynamic tests than those with mild DPN. Future studies should investigate the relationship between neurodynamic tests and nerve function in other conditions. This supports previous research on negative neurodynamic tests in severe neuropathy, suggesting that neurodynamic tests should not be used alone to determine nerve involvement.