Bruxism occasional tooth grinding. It has been shown that the majority (86%) of sleep bruxism episodes occur during periods of sleep arousal. One study reported that sleep arousals which were experimentally induced with sensory stimulation in sleeping bruxists triggered episodes of sleep bruxism. Sleep arousals are a sudden change in the depth of the sleep stage, and may also be accompanied by increased heart rate, respiratory changes and muscular activity, such as leg movements. Initial reports have suggested that episodes of sleep bruxism may be accompanied by gastroesophageal reflux, decreased esophageal pH (acidity), swallowing, and decreased salivary flow. Another report suggested
Involuntary narrative same object, media or technology are perceived as a continuum. When a purposeful overlap of the physical and the virtual takes place, it could be called vireal (Gramelsberger, Klein). The involuntary narrative, hypnagogia and the Dreamachine, trigger what is already in the individual by referring to his or her own past history. The involuntary narrative is accidental and in that differs from both the hypnagogic state and the state induced by the Dreamachine. Auditive and visual signals, as for example mobile phone ringtones, virtual identity thumbnails, alert sounds, signals and information screens in public transport, adverts displayed in LED screens,