A new test protocol and device for measuring the cranio-cervical flexion test in participants with bruxism.

Introduction: The craniocervical flexion test (CCFT) has been proposed to assess muscular stabilization using deep neck flexors. Reliability of the CCFT using a pressure biofeedback unit has been regarded as doubtful, and the level of evidence is reportedly low.The aim of the current study is to pilot test an alternative measurement protocol by using a new digital device during the staged CCFT when compared to surface electromyography (sEMG) of neck flexor muscles in participants with bruxism.

Methods: Cross-sectional pilot study including five participants with bruxism and five controls. Measuring five incremental stages (20-100%), from a maximum force of 17 N for the CCFT and parallel to sEMG measurements of bilateral sternocleidomastoideus (SCM) and masseter muscles. SEMG data were normalized to their activity during maximal voluntary contraction. Performance during the staged CCFT was fed back via a smartphone screen.

Results: A two-way repeated measures ANOVA found a significant stage (F = 32.56, df = 4, p = 0.001) but not group (0.30, df = 1, p = 0.65) main effect for SCM activity, with both groups demonstrating higher normalized sEMG activity for incremental stages of the CCFT. Neither group nor stage effects were found for normalized masseter activity during the staged CCFT.

Conclusion: A new measurement protocol and test device for the CCFT were examined in participants with and without bruxism. In parallel, sEMG used showed differences in SCM activity for incremental test stages. Group differences could not be found.