Neurological symptomatology
Confusional arousals are associated with behavioural awakening with persistent slow-wave electroencephalographic activity (see slow-wave sleep) during Non-rapid eye movement sleep (NREM). It suggests that sensorimotor network is activated while non sensorimotor areas are still "asleep". The altered state of consciousness may be explained by a hypersynchronous delta activity (see delta wave) in network involving the frontoparietal cortices (suggesting to be "asleep"), and higher frequency activities in sensorimotor, orbitofrontal, and temporal lateral cortices (suggesting an "awakening"). Sleep-related violence and abnormal sexual behaviours
Confusional arousals have often been linked to sleep-related violence (self-injury or injury to the bed partner). The latter highlights important medical and legal issues when such behaviours are suspected and purported to have caused a criminal offense. The first documented case of homicide as a result of confusional arousal was reported in medieval times by the case of the Silesian woodcutter Bernard Schedmaizig. Sleep-related abnormal sexual behaviours (also called sexsomnia or sleep sex) are mainly classified as confusional arousals and more rarely associated to sleepwalking (also known as somnambulism). Even if sleep-related violence may occur during an episode of confusional arousal, it remains extremely rare and there are no specific predisposition to aggression during these episodes. Distinction between sleepwalking and night terrors
Violent behaviours in confusional arousals slightly differ from those in sleepwalking or night terrors. Above all, during an episode of confusional arousal the patient never leaves the bed unlike sleepwalking.
A bed partner or parent who tries to calm or restrain the patient by grabbing him or her may trigger a violent reaction as with sleepwalkers. In case of a confusional arousal triggered by an attempt of awakening the patient, violent behaviours may occur almost spontaneously. Unlike confusional arousals and sleep walking, patients experiencing night terrors seem to react to some type of frightening image. Therefore, the violent reaction may occur if another individual is encountered or is in proximity. Classification
International Classification of Sleep Disorders (ICSD)
According to the 2nd edition of the International Classification of Sleep Disorders (ICSD-2), confusional arousals are classified in NREM parasomnias embedded in the non-epileptic paroxysmal motor events during sleep, which include (1) Parasomnia, (2) Sleep-related movement disorders and (3) Isolated symptoms, apparently normal variants and unresolved issues. NREM parasomnias (or disorders of arousal) also include sleep terrors (see night terror) and sleepwalking. Confusional arousals are characterised by more or less complex movements without leaving bed with whimpering, sitting up in bed and some articulation without walking or terror. In comparison of other arousal parasomnias the age onset of sleep walking is generally between 5 and 10 years whereas confusional arousals and sleep terror may occur 3 years earlier. Sleep terrors are mainly characterised by screaming, agitation, flushed face, sweating and only share the inconsolability with confusional arousals. The current 3rd edition of the International Classification of Sleep Disorders (ICSD-3) added the sleep-related eating disorders in the disorders of arousal from NREM sleep.