Objective REM sleep characteristics of recurrent isolated sleep paralysis: a case-control study

Study Objectives Recurrent isolated sleep paralysis (RISP) is a rapid eye movement (REM) parasomnia characterized by a dissociative state with characteristics of REM sleep and wakefulness. Pathophysiology has not yet been clarified and very little research has been performed using objective polysomnographic measures with inconsistent results. The main aim of our study was to find whether higher REM sleep fragmentation is consistent with the theory of state dissociation or whether signs of dissociation can be detected by spectral analysis. Methods Nineteen participants in the RISP group and 19 age- and gender-matched participants in the control group underwent two consecutive full-night video-polysomnography recordings with 19-channel electroencephalography. Apart from sleep macrostructure, other REM sleep characteristics such as REM arousal index, percentage of wakefulness and stage shifts within REM sleep period were analyzed, as well as power spectral analysis during REM sleep. Results No difference was found in the macrostructural parameters of REM sleep (percentage of REM sleep and REM latency). Similarly, no significant difference was detected in REM sleep fragmentation (assessed by REM sleep arousal index, percentage of wakefulness and stage shifts within REM sleep). Power spectral analysis showed higher bifrontal beta activity in the RISP group during REM sleep. Conclusions The results showed an underlying persistent trait of higher cortical activity that may predispose patients with SP to be more likely to experience recurrent episodes, without any apparent macrostructural features including higher REM sleep fragmentation.

Nightmare Disorder and Isolated Sleep Paralysis

Nightmare disorder and recurrent isolated sleep paralysis are rapid eye movement (REM) parasomnias that cause significant distress to those who suffer from them. Nightmare disorder can cause insomnia due to fear of falling asleep through dread of nightmare occurrence. Hyperarousal and impaired fear extinction are involved in nightmare generation, as well as brain areas involved in emotion regulation. Nightmare disorder is particularly frequent in psychiatric disorders and posttraumatic stress disorder. Nonmedication treatment, in particular imagery rehearsal therapy, is especially effective. Isolated sleep paralysis is experienced at least once by up to 40% of the general population, whereas recurrence is less frequent. Isolated sleep paralysis can be accompanied by very intense and vivid hallucinations. Sleep paralysis represents a dissociated state, with persistence of REM atonia into wakefulness. Variations in circadian rhythm genes might be involved in their pathogenesis. Predisposing factors include sleep deprivation, irregular sleep–wake schedules, and jetlag. The most effective therapy consists of avoiding those factors.

1227 A CASE OF A FEARFUL SLUMBER

Introduction Isolated sleep paralysis (ISP) occurs when rapid eye movement (REM)-based atonia intrudes into wakefulness, outside the context of narcolepsy, substance abuse, mental disorder or other medical conditions. No “gold standard” assessment and diagnostic instrument currently exists. Report of Case A 63-year old female with hypersomnia and positive airway pressure (PAP)-controlled obstructive sleep apnea was referred for recurrent episodes of paralysis during sleep-wake transitions, lasting 15-20 seconds, occurring every 2-3 years since the age of 15, and associated with fear and anxiety. Episodes were more frequent in the last 2 years after significant sleep deprivation and starting a weight loss supplement, BIO-X4, which contains green tea and probiotics. No cataplexy, or history of traumatic brain injury and stroke were identified. Epworth Sleepiness Scale score was 14 on armodafinil. Reported sleep amounts were regularly scheduled 6-7-hour periods, with no suggestion of circadian dysfunction. In 2016, polysomnogram showed Apnea-Hypopnea index of 2.6/hour, Respiratory Disturbance Index of 13.8/hour with oxygen nadir of 92% in the setting of hypersomnia. Continuous PAP of 11 cmH20 was initiated after a successful titration with controlled residual AHI during follow-ups. Multiple Sleep Latency Test during the same time revealed mean sleep latency of 5.5 minutes and no sleep-onset REM with 5 naps. Brain imaging and electroencephalogram were both normal as well as drug panel, blood counts, metabolic profile and thyroid function. Decreased episodes and severity of recurrent ISP were reported after discontinuation of the supplement. Apart from anxiety related to the episodes, the patient denied any interference with daytime function. Conclusion Isolated sleep paralysis is an important sleep disorder that requires proper evaluation to rule out competing diagnoses and consideration of therapeutic interventions. Likely associated with a lack of understanding and available literature, the prevalence in the general population is likely higher than what is currently perceived.

RECURRENT SLEEP PARALYSIS - FEAR OF SLEEPING

ABSTRACT Objective: To report a case of recurrent isolated sleep paralysis (RISP), a benign parasomnia with worrisome and frightening sleep paralysis episodes. Case description: We describe a case of RISP in a sixteen-year-old girl who seeks medical attention for anxiety symptoms. The sleep paralysis and associated auditory and tactile hallucinations began three years before with worsening in the last year, causing fear of sleeping. The episodes were intensely frightening causing negative impact in patient’s sleep, school performance and social function. Medical conditions were excluded, and she started treatment with a selective serotonin reuptake inhibitor with complete resolution of symptoms. Comments: Sleep complaints are often devalued. Therefore, clinicians should actively ask their patients about their sleep during health assessment.