Reliability and difference in neck extensor muscles strength measured by a portable dynamometer in individuals with and without chronic neck pain.

OBJECTIVE: There are limited reports about the reliability of measuring neck extensor muscle strength using a portable dynamometer in neck pain patients. The aims of the current study were 1) to investigate intra- and inter-rater reliability of neck extensor isometric strength measurement using a portable dynamometer in patients with chronic nonspecific neck pain (CNSNP) and 2) to compare neck extensor isometric strength in participants with and without CNSNP. METHODS: Guidelines for Reporting Reliability and Agreement Studies (GRRAS) were followed. Two examiners received a 15-minute training before enrollment. Inter-rater reliability was assessed with a 10-minute interval between measurements, and intra-rater reliability was assessed with a 10-day interval. Three trials were assessed and examiners were blind to the strength values (in Newtons) from other sessions of 20 individuals with CNSNP (mean±SD= 37.9 ± 9.8y; Neck Disability Index 29.2 ± 7.4%) and 20 individuals with other musculoskeletal disorders (mean ± SD = 32.8 ± 46.2y). RESULTS: Intra-rater reliability was excellent with intraclass correlation coefficient (ICC)(3,1) of 0.95 (CI:0.90-0.97) and inter-rater reliability was good to excellent with ICC(2,1) of 0.88 (CI:0.77-0.94) in CNSNP. No significant difference of neck extensor strength was found between CNSNP (93.27N±31.94) and Individuals without CNSNP (111.43N±40.11) (p > 0.05). CONCLUSION: A portable dynamometer is a reliable tool for measuring maximal isometric neck extension strength in individuals with CNSNP. Slightly but no significant differences of neck extensor strength values between individuals with and without CNSNP. Future studies are needed to assess the generalizability of the findings in patients with other muscle deconditioning.

Diagnostic accuracy of upper limb neurodynamic tests in the diagnosis of cervical radiculopathy.

BACKGROUND: Upper limb neurodynamic tests (ULNT) are used to diagnose neuropathic conditions such as cervical radiculopathy (CR). Within the literature, a positive ULNT is defined in markedly variable ways, which is likely why the diagnostic accuracy of these tests lacks consistency across studies. OBJECTIVES: To determine the diagnostic accuracy of single and combined upper limb neurodynamic tests ((ULNT)1,2a, 2b and 3) for cervical radiculopathy using test findings that are similar to those used in practice. DESIGN: Diagnostic accuracy study (prospective) design following the updated STARD 2015 reporting guideline. METHOD: From 109 consecutively enrolled individuals with suspected CR. Of the 85 participants included, 27 (31.7%) were diagnosed with CR (mean age, 43.9years; Neck Disability Index 38,16%). ULNTs test were performed by a blind examiner to a CR reference standard of clinical diagnosis and magnetic resonance imaging verification provided by a neurosurgeon. RESULTS: In general, the single tests were better at ruling in CR versus ruling out. Of the single ULNT, the ULNT3 demonstrated the strongest post-test probability change with a positive finding (73.28%). Three of four test combinations demonstrated the highest clinical utility for changing the post-test probability with a positive finding at 83.29% and with LR+ = 12.89 (95%CI: 3.10-53.62). Having none of the test's positive was able to rule out CR with LR- = 0.08 (95%CI: 0.01-0.56). CONCLUSION: ULNTs fail to significantly alter post-test probability when used singularly for diagnosis of CR. However, combinations of ULNT (3 out of 4 positive) can rule in CR, and rule out CR when all ULNT are negative.