Background: Disturbed cervical proprioception has been reported in neck pain conditions. Proprioception can be defined as the conscious and unconscious awareness of joint position, movement, force, heaviness and effort. While cervical proprioception is commonly assessed with joint position sense or movement sense tests, research investigating cervical force sense is scarce. There is a need for valid and reliable force sense tests for research and clinical use.

Purpose:  Evaluate the discriminant validity of a cervical force sense test in neck extension by comparing patients with neck pain and healthy controls, using a Nintendo Wii Balance Board.

Method: Forty-two participants (44.6 ±12.7 years, 76% females) were recruited, 22 with neck pain (NP) and 20 asymptomatic controls (CON). Maximum voluntary isometric contraction (MVIC) force was assessed, followed by force reproduction and force steadiness tasks, both at 10% and 20% of MVIC. Outcome variables were constant error, variable error and absolute error for force reproduction and coefficient of variation (CoV), standard deviation and mean absolute error for force steadiness. Group differences were analyzed with independent t-test or Mann-Whitney U-test. Association between force sense and neck disability index (NDI) was analyzed with Pearson’s correlation. 

Results: The MVIC test showed significantly reduced strength among NP (p=0.022, effect size 0.124). The force sense tests showed significant group differences in force steadiness CoV 10% (p=0.023, effect size 0.122) and CoV 20% (p=0.049, effect size 0.093), while no significant group difference was seen in force reproduction. Moderate positive correlations existed between NDI and CoV 10% (p=0.043, r=0.456) and CoV 20% (p=0.043, r=0.455) in the NP group.  

Conclusion: Neck pain patients had reduced muscle strength and deficits in force steadiness. Effect sizes of the difference was small, indicating a limited validity of the test. Future studies should evaluate other psychometric properties, e.g., responsiveness; and include other NP groups, e.g., cervical dizziness or whiplash disorders. Testing procedure could include other movement directions.