Birgit Frauscher

Idiopathic rapid eye movement (REM) sleep behavior disorder (RBD) is a harbinger of synuclein-mediated neurodegenerative diseases. It is unknown if this also applies to isolated REM sleep without atonia (RWA). We performed a long-term follow-up investigation of subjects with isolated RWA. Participants were recruited from 50 subjects with isolated RWA who were identified at the sleep laboratory of the Department of Neurology at the Medical University of Innsbruck between 2003 and 2005. Eligible subjects underwent follow-up clinical examination, polysomnography, and assessment of neurodegenerative biomarkers (cognitive impairment, finger speed deficit, impaired color vision, olfactory dysfunction, orthostatic hypotension, and substantia nigra hyperechogenicity). After a mean of 8.6 ± 0.9 y, 1 of 14 participating subjects (7.3%) progressed to RBD. Ten of 14 RWA subjects (71.4%) were positive for at least one neurodegenerative biomarker. Substantia nigra hyperechogenicity and presence of mild cognitive impairment were both present in 4 of 14 subjects with isolated RWA. Electromyographic activity measures increased significantly from baseline to follow-up polysomnography ("any" mentalis and both anterior tibialis muscles: 32.5 ± 9.4 versus 52.2 ± 16.6%; p = 0.004). This study provides first evidence that isolated RWA is an early biomarker of synuclein-mediated neurodegeneration. These results will have to be replicated in larger studies with longer observational periods. If confirmed, these disease findings have implications for defining at-risk cohorts for Parkinson disease.

S and full research articles published in SLEEP, the official journal of the APSS. Sleep and sleep disorder scientific findings.

Despite several polysomnographic normative studies and multiple surveys of sleep disorders in the general population, few data have been collected on healthy sleepers. We aimed to survey the characteristics of healthy sleep. We prospectively investigated the sleep history of 100 subjects of a representative population sample who reported undisturbed sleep and in whom relevant sleep disorders were ruled out by a two-step screening procedure. Approximately four subjects had to be contacted for identifying 1 eligible subject who participated. The median reported time in bed was from 23:00 (21:30-02:00) to 07:00 (05:30-11:00). The total sleep duration was 7.3 h (5-10 h), varying from 7.5 h in the age group ≤ 30 years to 7 h in subjects aged 40-60 years and to 8 h in subjects > 60 years (p = 0.002). The median sleep efficiency was high (93.3%, range: 55.6% to 100%). Fifty-one subjects reported occasional snoring. Forty-five subjects reported sporadic non-bothersome sleep-related movement disorders (25 sleep-related leg cramps, 22 lifetime bruxism, 5 restless legs syndrome), and 36 had a history of sporadic non-bothersome parasomnias (27 nightmares, 12 sleepwalking, 1 sleep paralysis). In this population of healthy sleepers, snoring is the most common finding. Moreover, non-bothersome forms of recognizable sleep-related movement disorders and parasomnias are surprisingly common. These findings may suggest that diagnostic criteria of sleep disorders should not only be based on the presence of symptoms but also account for a minimum frequency or discomfort.

S and full research articles published in SLEEP, the official journal of the APSS. Sleep and sleep disorder scientific findings.

A diagnosis of definite REM sleep behavior disorder requires both a positive history for REM sleep behavior disorder and polysomnographic demonstration of REM sleep without atonia. To improve and facilitate screening for REM sleep behavior disorder, there is a need for simple clinical tools with sufficient sensitivity and specificity for the identification of subjects with probable REM sleep behavior disorder. We developed a short REM sleep behavior disorder screening questionnaire with 7 REM sleep behavior disorder– and 2 non‐REM sleep behavior disorder–specific control items and performed a validation study in 70 REM sleep behavior disorder subjects and 140 sleep disorder controls. Response patterns to all 7 REM sleep behavior disorder–specific items differed between REM sleep behavior disorder and non‐REM sleep behavior disorder patients (all P < 0.05), whereas the 2 non‐REM sleep behavior disorder–specific control items did not differentiate between REM sleep behavior disorder and non‐REM sleep behavior disorder (all P > .05). In 5 of the 7 REM sleep behavior disorder–specific items, AUC was greater than 0.700. These 5 items were included in the Innsbruck REM sleep behavior disorder inventory. In this questionnaire, a cutoff of 0.25 (number of positive symptoms divided by number of answered questions) had a sensitivity of 0.914 and a specificity of 0.857 for both idiopathic and Parkinson's‐related REM sleep behavior disorder (AUC, 0.886). The Innsbruck REM sleep behavior disorder inventory is a promising, easy‐to‐use, short screening tool for REM sleep behavior disorder with excellent sensitivity and specificity for both idiopathic and Parkinson's‐related REM sleep behavior disorder. © 2012 Movement Disorder Society