Tomoko Yagi

Daytime sleepiness and automobile accidents in patients with obstructive sleep apnea syndrome.

Abstract We evaluated the rate of automobile accidents and daytime sleepiness using the Epworth sleepiness scale (ESS) in 44 patients with obstructive sleep apnea syndrome (OSAS). We defined the automobile accident score as a sum of two points for every one automobile accident and one point for every near‐miss accident. Automobile accidents and near‐misses were found in 54.5% and 50.0% in patients with OSAS. Automobile accident score was significantly correlated with the ESS score (r= 0.56, P < 0.01). Our findings suggest that ESS score may be useful in detecting patients with the potential risk of automobile accidents associated with daytime sleepiness.

Factors influencing subjective sleepiness in patients with obstructive sleep apnea syndrome

Abstract  The aim of the present paper was to clarify the factors influencing subjective daytime sleepiness in patients with obstructive sleep apnea syndrome (OSAS). Subjects included 230 adult male OSAS patients aged 20–73 years. Single and multiple linear regression analyses were performed to estimate the association between the Epworth Sleepiness Scale (ESS) and the following variables: Minnesota Multiphasic Personality Inventory (MMPI), Self‐Rating Depression Scale (SDS), age, body mass index (BMI), sleep duration during the preceding month and apnea–hypopnea index (AHI). Single linear regression analysis showed that age had a negative association with ESS score, while BMI, AHI, SDS, hypochondriasis (Hs), hysteria, psychopathic deviant, psychasthenia, schizophrenia and hypomania on the MMPI had a positive association with ESS score. However, the other remaining parameters such as nocturnal sleep duration during the preceding month, depression, masculinity–femininity, paranoia, social introversion on the MMPI had no statistical association with ESS score. Multiple linear regression analysis with stepwise elimination method was applied to choose the significant factors associated with ESS. It was found that three variables including age, AHI and Hs scores were independent factors influencing ESS score. The R2 for the model was 0.14, suggesting that these factors account for 14% of possible variance of subjective daytime sleepiness of OSAS patients. These results suggest that subjective daytime sleepiness in patients with OSAS may be influenced not only by the severity of respiratory disorder indices but also by certain personality characteristics affecting Hs score and by age.

Phase of nasal cycle during sleep tends to be associated with sleep stage

The phenomena of periodic cycles of vascular engorgement on the nasal cavity mucosa that alternate between right and left sides are termed the “nasal cycle.” The physiologic mechanisms underlying this cycle have not been entirely clarified, even more so during sleep. In this study, we measured the periodic patterns of the normal nasal cycle, not only during wakefulness but also during sleep.

For children's sleep assessment: Can we trace the change of sleep depth based on ECG data measured at their respective home with a wearable device?

We tried to improve the sleep assessment method from the accelerations (ACC) and RR interval variations (RRIV) thar were measured with newly developed small and light-weight wearable ECG and ACC measuring devices (M-BIT). We performed the simultaneous measurement of M-BIT and polygraph, and verified the validity of our ACC-based sleep/awake identification method, and studied the relationships among parameters obtained through the time frequency analysis of M-BIT ECG RRIV, para-sympathetic (PSNS) and sympathetic nervous systems activity (SNS), coefficients of variation of RR intervals (CVRR), RRIV based respiration frequency (RFRE), its variation width in an epoch (VRFRE), heart rate (HR), and polygraph sleep stages.

S26-6 CAP (cyclic alternating pattern) in psychiatric disorder

Periodic leg movements during sleep (PLMS) is frequently observed in rapid eye movement (REM) sleep behavior disorder (RBD) especially during REM sleep period. We made a series of studies for investigating the clinical significance and the underlying mechanism of PLMS in RBD. Consecutive 54 patients with idiopathic RBD without PLMS (iRBD w/o PLMS, 65.9±6.9 yrs), 27 patients with iRBD with PLMS (iRBD-PLMS, 67.7±7.1 yrs), and 31 patients with idiopathic PLMS (iPLMS, 63.5±5.9 yrs) were enrolled. Scores of Epworth Sleepiness Scale (ESS) were compared among the three patients groups. PLMS index, mean duration of PLMS, and inter-PLMS interval were calculated during both NREM sleep period and REM sleep period respectively, and compared among the three patient groups. Correlation analysis between ratio of PLMS related arousal index to PLMS index (PLMAI/PLMI) and proportion of REM sleep without atonia to total REM sleep (RWA/REM) were performed in the iRBD-PLMS group. The associated factor for the presence of PLMS during REM sleep period was also investigated in the subject iRBD group. In 15 out of iRBD-PLMS patients, effectiveness of the treatment with pramipexole, a dopamine agonst, was also evaluated. The iRBD-PLMS group showed significantly lower ESS score than the iPLMS w/o PLMS group did. PLMAI/PLMI was negatively correlated with RWA/REM. The iRBD-PLMS group showed significantly higher PLMS index, longer duration of PLMS, and shorter inter-PLMS interval than the iPLMS group did. RWA/REM appeared as a significantly associated factor for the presence of PLMS during REM sleep period among the iRBD patients. However, pramipexole treatment did not show a statistical decrease in the amount of PLMS. Conclusions: RWA could be associated with attenuation of arousal response to PLMS possibly leading to lower daytime sleepiness in iRBD. Our result impresses that PLMS during this sleep period could become an disease process marker of iRBD.

125. Cyclic alternating pattern of Sleep Apnea Syndrome in children evaluated before and after tonsillectomy

Laboratory sleep studies in posttraumatic stress disorder (PTSD) have not provided consistent evidence of sleep disturbance, despite apparent sleep complaints. Most of these studies have investigated middle-aged chronic PTSD subjects with a high prevalence of comorbidities such as substnce and/or personality disorder. In this study, ten young adult PTSD patients without comorbidities of substance dependence and/or personality disorder underwent 2-night polysomnographic recordings. These sleep measures were compared with those of normal control subjects and were correlated with PTSD symptoms. PTSD patients demonstrated significantly poorer sleep, reduced sleep efficiency caused by increased wake time after sleep onset, and increased awakening from rapid eye movement (REM) sleep (REM interruption). We found significant positive correlations between the severity of trauma-related nightmare complaints and the percentage of REM interruption, as well as wake time after sleep onset. The results indicate that trauma-related nightmares are an important factor resulting in increased REM interruptions and wake time after sleep onset in PTSD.

55. New sleep electroencephalogram analysis, CAP (Cyclic Alternating Pattern) method for sleep study and clinical use

A 20-year-old woman has suffered from myalgia and involuntary movements in the lower extremities since age 10. Her developmental history was normal and the family history was non-contributory. On examination, myokymia-fasciculation was observed in the lower extremities and worsened by exercise and exposure to cold, however, other neurological examination was unremarkable. The blood tests were unremarkable including negative antibody against voltage-gated potassium channel (VGKC). The tibial F study showed prolonged afterpotential after the appearance of the F waves. Needle EMG showed fasciculation potentials and doublets–triplets in the lower extremities. Threshold tracking demonstrated the following abnormalities: (1) recovery cycle showing complete lack of late subexcitability, (2) depolarizing threshold electrotonus showing lack of accommodation (S2), (3) the remarkably decreased strength-dependent time constant. These recording was similar to the ones recorded in rats by applying the selective KCNQ channel blockers XE991 (Schwarz et al., 2006). We concluded that slow potassium channel dysfunction caused axonal hyperexcitability demonstrating fasciculation-myokymia. Thus, threshold tracking is useful in identifying channelopathy in a non-invasive manner.

Preliminary evaluation of cyclic alternating pattern (CAP) in Japanese insomniac patients

recorded before lights out until the termination of the first REM sleep in 14 young healthy subjects. The subject remained in a semirecumbent posture in dim light during waking period before light out. The effects of circadian rhythm were controlled. Heart rate variability was calculated using the MemCalc method from electrocardiogram R–R intervals. The heart rate variability was analyzed in time course changes before and after sleep onset. The LF/(LF+HF) and LF/HF declined clearly prior 30 min to sleep onset. The HF increased prior to sleep onset in consecutive phases. The change of LF/(LF+HF) and LF/HF preceded slow wave sleep and REM sleep. There was no clear stage dependency after sleep onset in HF. The results mentioned above suggest that the cardiac sympathetic nervous activity represented LF/ (LF+HF) and LF/HF may possibly anticipate sleep and each sleep stage onset.