[Agrypnia (organic insomnia)]

The word agrypnia, ie, organic insomnia, was first used to describe a patient with a Morvan fibrillary chorea, which is an ill-delineated syndrome. This review considers the experimental insomnia created by raphe nuclei, anterior hypothalamic, or thalamic lesions. There are some papers reporting REM and non-REM sleep reduction in man after vascular, traumatic or degenerative lesion of the pons. There is only one case of agrypnia due to a bilateral stereotatic thalamic injury. Infectious agrypnia (trypanosomiasis, Von Economo) may exist but has not been documented by polygraphic means. Fatal familial insomnia induces a precocious agrypnia and leads to death with vegetative and motor disturbances. It is associated with an abnormal prion-protein which may interfere with gabaergic synapses. Finally agrypnia in humans corresponds to either lesionnal or infra microscopic synaptic prion linked disorders.