Short-term relaxation after cervical rotatory manipulation is more closely associated with somatosensory input than cracking sound: a randomized controlled EEG study

The study examined whether short-term relaxation after cervical rotatory manipulation of the neck is more related to the manipulation itself or to the cracking sound that often accompanies it. A randomized controlled study included 54 healthy volunteers divided into three groups: real manipulation, sham manipulation, and sham manipulation with simulated cracking sound. Results showed that real cervical rotatory manipulation led to greater improvements in positive emotions, comfort, and satisfaction compared to sham manipulations. These subjective changes were accompanied by changes in brain electrical activity, particularly in frontal brain regions. Simulated cracking sound alone did not reproduce the full response observed after real manipulation. The research provides evidence that the relaxation effect of manipulation is primarily caused by the manipulation itself and its physical impact, not by the cracking sound.