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Objective: To determine if the P50 midlatency auditory evoked potential, a sleep state-dependent waveform thought to be generated by the reticular activating system, is modulated after surface stimulation of acupuncture points (ie, electroacupuncture)., Design: P50 potential recordings were carried out before, during, and after electroacupuncture., Setting: A clinical research center., Participants: Eighty healthy subjects ages 25 to 55 were recorded in 7 investigations., Interventions: Stimulation of 3 specific acupuncture points (Pericardium 6, Heart 3, Liver 3) was compared with no stimulation or with stimulation of control points (Gall Bladder 34, Large Intestine 11, Small Intestine 3). We compared different frequencies of stimulation (5, 60, 100 Hz), unilateral versus bilateral stimulation, and the effects of repeated episodes of stimulation., Main Outcome Measures: P50 auditory evoked potential latency, amplitude (measure of level of arousal), and habituation (measure of sensory gait) at interstimulus interval of 250 ms., Results: Electroacupuncture at specific points decreased P50 potential amplitude versus electroacupuncture at control points (P=.006) or versus no stimulation (P<.001). The optimal effective frequency was 5 Hz (P<.05 at 5 Hz, P>.05 at 60 and 100 Hz), and unilateral electroacupuncture was not as effective as bilateral electroacupuncture (P=.007). Repeated episodes of bilateral electroacupuncture showed additive effects (P<.05). There were no differences in responsiveness across sexes (P=.79), and electroacupuncture did not affect P50 potential habituation (P>.05)., Conclusions: Electroacupuncture may be effectively used to decrease arousal levels, perhaps as adjunct therapy for disorders of hypervigilance.

Sopite syndrome, characterized by loss of initiative, sensitivity to normally innocuous sensory stimuli, and impaired concentration amounting to a sensory gating deficit, is commonly associated with Space Motion Sickness (SMS). The amplitude of the P50 potential is a measure of level of arousal, and a paired-stimulus paradigm can be used to measure sensory gating. We used the rotary chair to elicit the sensory mismatch that occurs with SMS by overstimulating the vestibular apparatus. The effects of rotation on the manifestation of the P50 midlatency auditory evoked response were then assessed as a measure of arousal and distractibility. Results showed that rotation-induced motion sickness produced no change in the level of arousal but did produce a significant deficit in sensory gating, indicating that some of the attentional and cognitive deficits observed with SMS may be due to distractibility induced by decreased habituation to repetitive stimuli.

Sopite syndrome, characterized by loss of initiative, sensitivity to normally innocuous sensory stimuli, and impaired concentration amounting to a sensory gating deficit, is commonly associated with Space Motion Sickness (SMS). The amplitude of the P50 potential is a measure of level of arousal, and a paired-stimulus paradigm can be used to measure sensory gating. We used the rotary chair to elicit the sensory mismatch that occurs with SMS by overstimulating the vestibular apparatus. The effects of rotation on the manifestation of the P50 midlatency auditory evoked response were then assessed as a measure of arousal and distractibility. Results showed that rotation-induced motion sickness produced no change in the level of arousal but did produce a significant deficit in sensory gating, indicating that some of the attentional and cognitive deficits observed with SMS may be due to distractibility induced by decreased habituation to repetitive stimuli. [ABSTRACT FROM AUTHOR]