RESUMEN
OBJECTIVE: As a noninvasive and nonpharmacological therapeutic approach, superficial acupuncture (SA) is a special method of acupuncture. In this study, using nonlinear dynamics and multivariate statistics, we studied the electroencephalography (EEG) of primary insomnia under SA intervention to investigate how brain regions change. METHOD: This study included 30 adults with primary insomnia. They underwent superficial acupuncture at the Shangen acupoint. The EEG signals were collected for 10 minutes at each state, including the resting state, the intervention state, and the postintervention state. The data were conducted using nonlinear dynamics (including approximate entropy (ApEn) and correlation dimension (CD)) and multivariate statistics. RESULT: The repeated-measures ANOVA results showed that both ApEn and CD values were not significantly different at the three states (p > 0.05). The paired t-test results showed that the ApEn values of electrodes O2 (the right occipital lobe) at the postintervention state have decreased, compared with the resting state (p < 0.05), and no difference was detected in CD (p > 0.05). The cluster analysis results of ApEn showed that patients' EEG has changed from the right prefrontal lobe (electrode Fp2) to the right posterior temporal lobe (electrode T6) and finally to the right occipital lobe (electrode O2), before, during, and after the SA intervention. In addition, the factor analysis results of CD revealed that patients' EEG of all brain regions except for the occipital lobes has changed to the frontal lobes and anterior temporal and frontal lobes from pre- to postintervention. CONCLUSION: SA activated the corresponding brain regions and reduced the complexity of the brain involved. It is feasible to use nonlinear dynamics analysis and multivariate statistics to examine the effects of SA on the human brain.
RESUMEN
OBJECTIVE: To evaluate the influence of superficial needling on electroencephalogram (EEG) in patients with insomnia by using nonlinear kinetics measure. METHODS: Six patients (3 male and 3 female) suffering from insomnia for more than a month were recruited in the present study. EEG data before and during superficial acupuncture stimulation of Shangen point (the midpoint between the bilateral inner canthus) was recorded using an electroencephalograph for analyzing the correlation dimensionality (D 2) and approximate entropy (ApEn) of different cerebral regions. RESULTS: During superficial needling, the D 2 data of the right-forehead (Fp 2), anterior area of the left temple (F 7) and the anterior region of the right temple (F 8) were significantly increased (P<0.05), and ApEn data at the right anterior forehead(Fp 2), left occipital region (O 1), and F 8 region markedly decreased relevant to pre-acupuncture (P<0.05). Both paring test and trend analysis of D 2 data showed no significant changes. Only an obvious increase of D 2 was found in the Fp 2 region, suggesting a coherence of EEG activities in stability and synchronization during acupuncture treatment. Clustering analysis of D 2 data of various cerebral regions displayed a relatively concentrated tendency, particularly in the Fp 2, the right forehead (F 4) and F 8 regions. Factor analysis of ApEn data showed a significant change in Fp 2, F 8, O 1 and right occipital (O 2) regions. It suggests that during superficial needling stimulation of Shangen point, the EEG signals were lowered in complexity, and improved in synchronization, stabilization and ordering, favoring sleep at last. CONCLUSION: Superficial needling of Shangen point can make the EEG signals synchronized in insomnia patients, suggesting an improvement of sleeping.