Stages 1–2 non–rapid eye movement sleep behavior disorder associated with dementia: A new parasomnia?

Abstract

A 55-year-old woman with a progressive dementia and frontal syndrome was hospitalized because she was agitated every night after falling asleep (spoke, laughed, cried, tapped, kicked, walked, and fell down). She slept 5.5 hours during video polysomnography, but the theta rhythm electroencephalograph recording typical of sleep stages 1 to 2 and the spindles and K-complexes typical of sleep stage 2 contrasted with continuous muscular twitching, prominent rapid eye movements, vocalizations, and continuous, complex, purposeful movements typical of rapid eye movement (REM) sleep behavior disorder. This newly described stages 1--2 non-REM sleep behavior disorder suggests that central motor pattern generators were disinhibited during non-REM sleep.

A novel non-rapid-eye movement and rapid-eye-movement parasomnia with sleep breathing disorder associated with antibodies to IgLON5: a case series, characterisation of the antigen, and post-mortem study

“…25 A previous case report with dementia and a sleep disorder defined as “Stages 1–2 NREM sleep behavior disorder” had some similarities with the findings of our patients, including the presence of finalistic behaviors in stages N1-N2 NREM sleep and RBD; however, the patient did not have identifiable N3. 26 We did not record sleepwalking or sleep terror episodes in any of the V-PSG performed in our patients, and together with the severe distortion of sleep architecture the diagnosis of overlap parasomnia is unlikely. 27 Another finding not described in any of the parasomnias mentioned above is the presence of OSA and stridor.…”

Is there a common motor dysregulation in sleepwalking and REM sleep behaviour disorder?

“…Ambulation is exceptional during REM sleep in the video‐clinical settings of RBD, except in a case with idiopathic RBD that we recently observed (Herlin et al ., ). Whether ambulation in patients with RBD corresponds to ambulation during RBD as in our unique case (Herlin et al ., ), to ambulation during NREM sleep arousals combined with non‐ambulatory RBD, to confusional arousals in any sleep stage in demented and/or hallucinated patients, to a status dissociatus or to a NREM and REM sleep arousal disorder (Arnulf et al ., ; Kushida et al ., ; Sabater et al ., ) is an interesting but unsolved enigma. The discovery of POD has questioned the existence of a more general underlying motor dyscontrol in all these cases.…”

Spectrum of rapid eye movement sleep behavior disorder (overlap between rapid eye movement sleep behavior disorder and other parasomnias)

“…A case of dementia with Lewy bodies demonstrated SD with nocturnal agitation and wandering that responded to rivastigmine therapy (3 mg), with control of abnormal nocturnal behaviors and partial restoration of normal sleep architecture (NREM‐REM sleep periods could be identified) confirmed by vPSG after 15 months of therapy 28 . A woman with frontal dementia and stages 1–2 sleepwalking (as a new category of parasomnia) 29 eventually developed SD prior to death (Isabelle Arnulf, personal communication). In a case of SD developing after resection of a ponto‐mesencephalic cavernoma in a 36‐year‐old man, clonazepam therapy over 2 years was effective in controlling the abnormal sleep and dream‐related behaviors, and was shown to selectively reduce the excessive REM sleep phasic motor activity, without restoring any REM‐atonia 30 .…”