Medline ® Abstracts for References 76-79

STUDY OBJECTIVES: The association of REM sleep without atonia (RSWA) as well as REM sleep behavior disorder (RBD) with the intake of selective serotonin reuptake inhibitors (SSRI) and selective norepinephrine reuptake inhibitors (SNRI) is well established. Our study objective was to determine the prevalence of RSWA and RBD among a group of sleep center patients taking SSRI and SNRI.

METHODS: A retrospective chart review was done at our tertiary sleep center, and 10,746 consecutive records from October 1, 2007, through October 31, 2013, were searched for SSRI and SNRI names using the Sleep Cataloguer Software.

RESULTS: The search resulted in 1,444 records, which were then reviewed for keywords of RSWA and RBD. The AASM scoring criteria were used to determine RSWA. Reports of 41 patients with known narcolepsy orα-synucleinopathies were excluded. The remaining records were mined for age, sex, presence of obstructive sleep apnea (OSA), type of antidepressant (SSRI or SNRI), and diagnosis for which antidepressant was prescribed. We used logistic regression analysis to adjust for age, OSA, and sex. Of the 1,444 participants on antidepressants, 176 (12.2%) had RSWA (all confirmed by the investigators) compared to 226 of the entire sleep lab population of 10,746 (2.1%), risk ratio (95% CI) 9.978 (8.149, 12.22). Seven of the 176 patients on antidepressants had RBD (0.48%) compared to 108 of 10,746 (1%), p = 0.005.

CONCLUSIONS: SSRI and SNRI are associated with a higher prevalence of RSWA but not of RBD. This is independent of medication type.

BACKGROUND: Rapid eye movement (REM) sleep without atonia (RWA) is observed in some patients without a clinical history of REM sleep behavior disorder (RBD). It remains unknown whether these patients meet the refined quantitative electromyographic (EMG) criteria supporting a clinical RBD diagnosis. We quantitatively evaluated EMG activity and investigated its overnight distribution in patients with isolated qualitative RWA.

METHODS: Fifty participants with an incidental polysomnographic finding of RWA (isolated qualitative RWA) were included. Tonic, phasic, and 'any' EMG activity during REM sleep on PSG were quantified retrospectively.

RESULTS: Referring to the quantitative cut-off values for a polysomnographic diagnosis of RBD, 7/50 (14%) and 6/50 (12%) of the patients showed phasic and 'any' EMG activity in the mentalis muscle above the respective cut-off values. No patient was above the cut-off value for tonic EMG activity or phasic EMGactivity in the anterior tibialis muscles. Patients with RWA above the cut-off value showed higher amounts of RWA during later REM sleep periods.

CONCLUSIONS: This is the first study showing that some subjects with incidental RWA meet the refined quantitative EMG criteria for a diagnosis of RBD. Future longitudinal studies must investigate whether this subgroup with isolated qualitative RWA is at an increased risk of developing fully expressed RBD and/or neurodegenerative disease.

The presence of either excessive tonic chin EMG activity during REM sleep, or excessive phasic submental or limb EMG twitching is required to diagnose REM sleep behavior disorder (RBD). The aim was to identify cut-off values and to assess the sensitivity and specificity of these values taken separately or combined to diagnose idiopathic RBD patients. Eighty patients presenting with a clinical diagnosis of idiopathic RBD and 80 age- and gender-matched normal controls were studied in the sleep laboratory. Receiver operating characteristic curves were drawn to find optimal cut-off values for three REM sleep EMG parameters. Tonic and phasic EMG activity were measured in the chin, but not in the limbs. Videos were examined during the recording but were not systematically reviewed by the authors. Total correct classification of 81.9% was found for tonic chin EMG density≥30%; 83.8% for phasic chin EMG density≥15% and 75.6% for≥24 leg movements per hour of REM sleep. Five patients did not fulfill any of these three polysomnographic (PSG) criteria. Conversely, one subject of the control group met the PSG criteria for RBD. This study estimates the diagnostic value of a visual scoring method for the diagnosis of idiopathic RBD and establishes cut-off values to be used in clinical and research set-ups. For the five RBD patients who did not show chin EMG abnormalities, it cannot be excluded that they had increased phasic EMG activity in the upper limbs and presented visible motor activity.

The current definition of rapid eye movement (REM) sleep without atonia has no quantitative character, and cut-off values above which the level of electromyographic tone can be considered to be 'excessive' are unclear. The aim of this study was to analyse the characteristics of chin electromyographic amplitude by means of an automatic approach in a large group of normal controls, subdivided into different age groups. Eighty-eight normal controls were included, subdivided into six age groups: preschoolers (≤6 years); schoolers (6-10 years); preadolescents (10-13 years); young adults (24-40 years); middle-aged (58-65 years); and old (>65 years). The average amplitude of the rectified submentalis muscle electromyographic signal was used for the computation of the REM sleep Atonia Index. Chin muscle activations were detected, and their amplitude, duration and interval analysed. REM sleep Atonia Index showed a progressive and rapid increase from the preschool age to school and preadolescent age, reaching the maximum in the young adult group; after this age a small decline was observed in the middle-aged and old subjects. Conversely, the number of movements per hour in REM sleep showed a 'U'-shaped distribution across these age groups, with the minimum in the preadolescent group and the two extremes (preschool age and old) showing similar average levels of activity. Our results show that REM sleep atonia develops continuously during the lifespan, and undergoes complex changes with different developmental trajectories for REM atonia and electromyographic activations during REM sleep. Different mechanisms might subserve these two phenomena and their differential developmental dynamics.