Motoharu Ohi

Responsiveness of jaw motor activation to arousals during sleep in patients with obstructive sleep apnea syndrome.

OBJECTIVESnWe aimed to characterize the association between jaw muscle contractions and respiratory events in patients with obstructive sleep apnea syndrome (OSAS) and to investigate the responsiveness of the contractions to respiratory events in comparison with that of leg muscles in terms of arousal types and sleep states.nnnMETHODSnPolysomnographic (PSG) recordings were performed in 19 OSAS patients (F/M: 2/17; 53.1 ± 13.7 years; AHI: 31.8 ± 19.9/h) with no concomitant sleep bruxism or other sleep-related movement disorders. Muscle contractions of unilateral masseter (MAS) and anterior tibialis (AT) muscles were scored during sleep in association with graded arousals (microarousals and awakenings) related or unrelated to apneahypopnea events.nnnRESULTSnArousals were scored for 68.2% and 52.3% of respiratory events during light NREM and REM sleep, respectively. Respiratory events with arousals were associated with longer event duration and/or larger transient oxygen desaturation than those without (ANOVAs: p < 0.05). Median response rates of MAS events to respiratory events were 32.1% and 18.9% during NREM and REM sleep. During two sleep states, MAS muscle was rarely activated after respiratory events without arousals, while its response rate increased significantly in association with the duration of arousals (Friedman tests: p < 0.001). A similar response pattern was found for AT muscle. Motor responsiveness of the two muscles to arousals after respiratory events did not differ from responsiveness to spontaneous arousals in two sleep stages.nnnCONCLUSIONnIn patients with OSAS, the contractions of MAS and AT muscles after respiratory events can be nonspecific motor phenomena, dependent on the duration of arousals rather than the occurrence of respiratory events.

Obstructive sleep apnea syndrome aggravated propriospinal myoclonus at sleep onset

Article history: Received 11 February 2011 Received in revised form 22 June 2011 Accepted 29 June 2011 Available online 26 October 2011 2011 Elsevier B.V. All rights reserved.

A case of severe obstructive sleep apnea mimicking REM sleep behavior disorder

The rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream-enacting behaviors related to the loss of the normal generalized skeletal muscle atonia during REM sleep, and shows REM sleep without atonia (RWA) during polysomnography (PSG). Patients with idiopathic RBD have been known to have a siginificantly increased risk of developing one of the α-synucleiopathies later in life, therefore the diagnosis of RBD is very important and must be dealt with carefully. A 51-year-old man was identified presenting dream-enacting behaviors and unpleasant dreams suggesting the diagnosis of RBD, in addition to snoring and excessive daytime sleepiness. Attended video-PSG excluded RBD showing REM sleep with atonia and without increased phasic EMG activity, and diagnosed with severe obstructive sleep apnea (OSA) with an apnea-hypopnea index of 30.1 demonstrating that the reported abnormal sleep behaviors occurred only during respiratory event-induced arousals. Continuous positive airway pressure therapy eliminated the abnormal behaviors, unpleasant dreams, snoring and daytime hypersomnolence. This case shows that severe OSA mimic the symptoms of RBD and that attended video-PSG is necessary to establish the diagnosis of RBD, and identify or exclude other causes of dream-enacting behaviors.

Subjective oropharyngeal symptoms for abnormal swallowing in Japanese patients with obstructive sleep apnea syndrome: a descriptive questionnaire study.

Objectives: This study aimed to investigate the prevalence of clinical symptoms related to abnormal swallowing in a large sample of obstructive sleep apnea syndrome (OSAS) patients. Methods:Oropharyngeal symptoms for abnormal swallowing were assessed by a self-administered questionnaire in 507 consecutive patients (females: 65, males: 442; mean age: 49.6u2009±u200912.6u200ayears old) with clinical symptoms of OSAS, enrolled for cardiorespiratory evaluation. Results:Overall, 16.2% of patients (82/507) had at least one symptom for abnormal swallowing and 6.3% (32/507) had two or more symptoms. The most frequent symptom was difficulty with coughing up phlegm during or after a meal (8.3%). Demographic, sleep, and clinical variables did not differ between the patients with and without abnormal symptoms. Conclusions:The results of the current study showed that 16% of middle-aged OSAS patients reported pharyngeal symptoms related to abnormal swallowing, regardless of the severity of OSAS.

M-H-074 TONIC AND PHASIC MUSCLE ACTIVITY IN REM SLEEP BEHAVIOR DISORDER

Introduction and Objectives: REM sleep behavior disorder (RBD) is characterized by the loss of the normal REM sleep skeletal muscle atonia, resulting in complex motor behaviors associated with dream mentation. The polysomnographical hallmarks of RBD include tonic/phasic loss of the muscle atonia of REM sleep (REM sleep without atonia; RWA). However, scoring RWA is not well established. We will describe our methods of scoring RWA and will discuss some unsolved issues of RWA scoring. Materials and Methods: The diagnosis of RBD was made based on the International Classification of Sleep Disorders 2nd criteria. The subjects were 20 consecutive patients (19 male and 1 female, mean age: 67.9±7.8 years) who underwent full PSG. In our RWA scoring based on “The AASM Manual for Scoring 2007”, increased EMG activity was counted separately according to the EMG activity patterns; tonic EMG, phasic pattern, and combined EMG activities. If chin EMG activity was present for more than 50% of each 30-second epoch, that epoch was scored as tonic. Phasic EMG density was scored from the chin EMG and represented the percentage of 3 second mini-epochs containing EMG activity lasting 0.1 to 5 seconds. We calculated the percentage of RWA, tonic REM, phasic and REM density. Results: The mean values of the proportions of REM and RWA as a percentage of total sleep time were 19.7±6.3% and 7.2±4.6%. The mean values of tonic REM percentage and phasic EMG activity during REM sleep were 26.0±19.8% and 18.7±7.9%. Conclusion: Some groups have reported cut off or mean values of RWA to diagnose RBD or to identify a predictor for the development of neurodegenerative diseases. Compared to this data, our tonic REM percentage and phasic activity was low. The causes of differences were unclear. Further investigation including a large scale study population will be necessary to clarify the adequate values.