Observing neck movements evokes an excitatory response in the sympathetic nervous system associated with fear of movement in patients with chronic neck pain.

The objective of this study was to evaluate the response of the sympathetic-excitatory nervous system in patients with chronic neck pain compared with a control group of asymptomatic subjects who underwent an intervention of watching activities involving movements in the neck region. Thirty participants were divided into two groups: patients with chronic neck pain (n = 15) and the control group (n = 15). The patients' neck disability, fear of movement and catastrophism were assessed with a self-report. The recorded variables related to the autonomic nervous system were skin conductance and skin temperature. The ANOVA test revealed significant differences in the increase in skin conductance in the chronic neck pain group after observing the activities (both in the photographs and video) at the end of the observation and 5 minutes after the intervention (p < .01; d > 0.80). There were no significant differences in skin temperature. Ultimately, the correlation analysis revealed a moderate positive correlation between kinesiophobia and skin conductance at 30 seconds (r = 0.53) and at 60 seconds (r = 0.52) of observing the activities in the video for the chronic neck pain group. Based on the results of the present study, we suggest that observing activities involving neck movements causes an activation of the sympathetic-excitatory nervous system in patients with chronic neck pain. These changes could be related to a fear of movement when faced with visual exposure to neck movements that could be interpreted as 'harmful' or 'dangerous'.