[Effects of thoracic press-rotate manipulation on electroencephalographic activity in healthy individuals]

To investigate the potential effects of crack sounds produced during thoracic press-rotate manipulation (TPRM) on brain electrical activity in healthy individuals.

Forty healthy volunteers underwent standardized TPRM at the sixth thoracic vertebra spinal segment and were categorized based on the presence or absence of audible crack sounds. Nineteen volunteers were assigned to the TPRM with-click group, consisting of 10 males and 9 females, with a mean age of(24.58±3.53) years and a mean BMI of(21.37±3.94) kg·m^-2. Twenty-one subjects were assigned to the TPRM without-click group, consisting of 10 males and 11 females, with a mean age of (24.11±3.42) years and a mean BMI of (22.82 ±3.88) kg·m^-2. Resting-state electroencephalography(EEG) was recorded before and after the intervention. Power changes in Delta, Theta, Alpha, and Beta waves were analyzed across six electrode channels (FZ, PZ, O1, O2, T7, and T8), Subjective feelings were assessed using the International Positive and Negative Affect Schedule-Short Form(I-PANAS-SF), while volunteers satisfaction was evaluated using a visual analogue scale(VAS).

No significant within-group differences in EEG power were observed before and after the intervention in either group(P>0.05). However, post-intervention between-group comparisons revealed significantly higher power in the Delta, Theta, Alpha, and Beta waves in the TPRM with crack sounds, particularly in the occipital, temporal, and frontal libe(P<0.05).

Crack sounds during TPRM may be associated with the modulation of brain electrical activity in specific frequency waves and lobe. These findings suggest a potential neurophysiological role for crack sounds in manual therapy, warranting further investigation in clinical populations.