LAUSR

Sleep-related hallucinations (SRH) may arise at sleep onset or on awakening from sleep and represent sleep-state dissociation with the abnormal intrusion or persistence of dreams into wakefulness. These multisensory experiences are usually visual but may be tactile and colored by emotions such as grief. We describe a patient who presented with episodes of visual and tactile hallucinations of being comforted by his late grandmother at sleep onset shortly after her death. A 20-y/o male with a history of autism spectrum disorder (ASD) presented with sleep onset insomnia related to disturbing multisensory hallucination temporally associated with the passing of his grandmother two years earlier. He sleeps for 5 hours nightly and experiences more frequent spells when sleep-deprived. The spells manifest within an hour of sleep onset and consist of the patient experiencing quasi-visual and tactile sensations of his grandmother wrapping her hands through his hair and hugging him. The episodes are associated with longing and sadness as this was customary for his grandmother as she comforted him to sleep when she was alive. The patient’s interpretation was that the episodes might represent his grandmother's attempt to communicate with him and keep him safe. Polysomnography depicted REM sleep latency of 107 minutes without evidence of REM sleep without atonia. There was no evidence of obstructive sleep apnea. Sensory and quasi-sensory experiences of the deceased (SED) is an inclusive and neutral term used to describe multisensory experiences of the presence of the deceased. Phenomenologically, post-bereavement hallucinations are more closely aligned with the ICD-3 classification of SRH. The patient’s spells of SED were likely facilitated by sleep deprivation. Emerging data also supports the presence of unusual somatosensory experiences leading to supernatural attribution to these experiences in ASD. With the passing of his grandmother, the combination of grief and sleep deprivation along with altered central sensory processing likely contributed to the SED. SED and SRH represent a spectrum of abnormal hallucinations following bereavement and are facilitated by sleep deprivation. In ASD, the episodes might emerge in response to altered central limbic sensory processing and represent an important mechanism of impaired REM sleep in Autism spectrum.