Validation of a Novel device for Assessing Neck Muscle Strength

The Neuromuscular Cranio-Cervical Device (NOD) was originally designed to evaluate Cranio-Cervical Flexion Test performance but can also be used as a handheld dynamometer for testing other muscle groups, including neck muscle strength. It offers a potential alternative to the Multi-Cervical Unit (MCU), a fixed dynamometer, more closely aligned with isokinetic dynamometry, the gold standard. However, its validity and reliability need to be established. This study aimed to evaluate concurrent validity compared to the MCU and inter- and intra-rater reliability of the NOD for measuring neck flexion and extension muscle strength.

Twenty participants were assessed for neck flexion/extension strength whilst in a seated position, with the measurements repeated over three sessions. Concurrent validity was assessed by comparing NOD measurements to the MCU using Pearson correlation coefficients, and reliability was determined using Intraclass Correlation Coefficients (ICCs).

Concurrent validity was strong for extension (r = 0.954) but lower for flexion (r = 0.705), indicating some variability in flexion measurements. Inter-rater reliability was good to excellent for both flexion (ICC = 0.931) and extension (ICC = 0.896). Intra-rater reliability for extension was good to excellent (ICC = 0.893), while flexion ranged from moderate to excellent (ICC = 0.844).

The NOD is a valid tool, particularly for extension measurements, although further refinement of testing is needed to improve the accuracy for flexion strength measurements. It is also reliable for both extension and flexion, showing promise as a practical, affordable, portable tool with real-time feedback for the assessment of neck muscle strength in clinical settings.