Taeko Sasai

Detecting deteriorated vigilance using percentage of eyelid closure time during behavioral maintenance of wakefulness tests.

Several researchers have investigated the relation between vigilance and ocular variables such as saccade, slow eye movement, pupil, blink, or eyelid closure. This study was undertaken to find the most effective indicator among these ocular variables for evaluating short-term (1 min) fluctuation of vigilance, and to investigate the ability of the most effective ocular variable for predicting deteriorated vigilance during behavioral maintenance of the wakefulness test (Oxford sleep resistance test: OSLER test). Nine healthy volunteers (two women, 19-30 years old, 23.4±3.9 years old) participated in this study. Ocular variables were recorded during the OSLER test at 10 A.M. and 2 P.M. before and after partial sleep deprivation (4h sleep). The periods during the OSLER test were divided into 1 min epochs. Each epoch was classified according to the number of consecutive missed responses. Decreased blink frequency and pupil diameter as well as increased percentage of eyelid closure time (PERCLOS) and slow eye movement were observed as the consecutive missed responses increased. Among these variables, PERCLOS showed the highest ability to detect occurrence of any missed response and three or more consecutive missed responses. Moreover, a missed response seldom occurred (0.2±0.2/20 trial/min) when PERCLOS was less than 11.5% per minute. Results suggest that, among the ocular variables, PERCLOS can prevent error or accident caused by low vigilance most effectively.

Regional cerebral blood flow changes in patients with idiopathic REM sleep behavior disorder.

Background:  Recent studies have shown an association between rapid eye movement sleep behavior disorder (RBD) and neurodegenerative disorders, especially alpha‐synucleinopathies.

Comparison of clinical characteristics among narcolepsy with and without cataplexy and idiopathic hypersomnia without long sleep time, focusing on HLA-DRB1( *)1501/DQB1( *)0602 finding.

BACKGROUND Clinical characteristics of narcolepsy without cataplexy (NA w/o CA) and its relation to positivity of HLA-DRB1( *)1501/DQB1( *)0602 remain unclarified. We investigated clinical features of NA w/o CA, particularly addressing HLA-DRB1( *)1501/DQB1( *)0602. METHODS Comparisons of the Epworth Sleepiness Scale (ESS), multiple sleep latency test (MSLT) variables, rapid eye movement (REM)-related symptoms, and treatment response to psychostimulant medication were made for four patient groups (narcolepsy with cataplexy; NA-CA, NA w/o CA HLA-positive, NA w/o CA HLA-negative, and idiopathic hypersomnia without long sleep time; IHS w/o LST). RESULTS Mean sleep latency was significantly shorter and the rate of reduction of ESS after medication was lower in both NA-CA and NA w/o CA HLA-positive groups than those in the IHS w/o LST group. Among the three narcoleptic groups, the NA w/o CA HLA-negative group showed the lowest REM latency and the highest reduction rate of ESS after treatment. Neither these subjective and objective sleepiness measures nor the treatment response measure was significantly different between this group and the IHS w/o LST group. CONCLUSIONS In NA w/o CA, HLA-positivity might affect hypersomnia severity and REM propensity. The NA w/o CA HLA-negative group and the IHS w/o LST group exhibit equivalent hypersomnia severity.

Comparison of the clinical features of rapid eye movement sleep behavior disorder in patients with Parkinson's disease and multiple system atrophy

Aims:  The aim of this study was to evaluate differences in the clinical presentation and polysomnographic characteristics of rapid eye movement sleep behavior disorder (RBD) between patients with Parkinsons disease (PD) and those with multiple system atrophy (MSA).

Validation of the Japanese version of the REM sleep behavior disorder questionnaire (RBDQ-JP)

BACKGROUND The rapid eye movement (REM) sleep behavior disorder (RBD) questionnaire (RBDQ)-Hong Kong was the first tool developed for quantifying the severity of RBD. This study was conducted to validate the Japanese version of the questionnaire and to investigate its reliability, validity, and responsiveness. METHODS Patients with idiopathic RBD and sex and age-matched healthy controls completed the Japanese version of the questionnaire (RBDQ-JP). In addition to the evaluation of its reliability and validity, the questionnaire scores were compared between those earned before and those earned after pharmaceutical treatment to assess the questionnaires responsiveness. RESULTS The questionnaire demonstrated high test-retest reliability and moderate internal consistency. The best cut-off score was 19/20 with a sensitivity of 97.2% and a specificity of 97.5%. Exploratory factor analysis revealed that the questionnaire consists of the following two factors: Factor 1, Dream and dream-related behaviors and Factor 2, Violent/complex behaviors. Among the patients, significant correlation was found between the rate of change of questionnaire score and the clinical global impression improvement score with pharmaceutical treatment (rs=-0.829, p<0.01). CONCLUSIONS The RBDQ-JP provides satisfactory reliability, validity, and responsiveness. The questionnaire is suitable for severity assessment and for assessing the RBD treatment outcome.

Correlations among insomnia symptoms, sleep medication use and depressive symptoms

Aim:  To elucidate the factors associated with insomnia symptoms and the use of sleep medication, and the correlations among insomnia symptoms, sleep medication use and depressive symptoms in the general population.

Differences in findings of nocturnal polysomnography and multiple sleep latency test between narcolepsy and idiopathic hypersomnia

OBJECTIVES To compare differences in nocturnal and daytime polysomnographic findings between narcolepsy (NA) with and without cataplexy (CA) and idiopathic hypersomnia without long sleep time (IHS w/o LST). METHODS Nocturnal polysomnography (n-PSG) and multiple sleep latency test (MSLT) findings were compared among subjects with NA with CA (n=52), NA without CA (n=62), and IHS w/o LST (n=50). RESULTS The NA with CA group had significantly more disrupted and shallower nocturnal sleep than the other groups. On MSLT, the IHS w/o LST group had significantly longer sleep latency (SL) compared with the two NA groups. The latter two groups did not show statistical differences in diurnal variation of SL. CONCLUSIONS The IHS w/o LST group had milder objective daytime sleepiness compared with the NA groups. In patients with NA, nocturnal sleep disturbances appeared only in cases with CA, despite a similar trend in diurnal changes in sleep propensity between the two NA groups. SIGNIFICANCE Objective nocturnal sleep disturbances are specific to NA patients with CA, whereas diurnal variations of sleep propensity are observed irrespective of the presence of CA among NA patients. These findings could be helpful for choosing optimal treatment plans for patients with these disorders.

Validation of the Japanese version of the Ford Insomnia Response to Stress Test and the association of sleep reactivity with trait anxiety and insomnia

OBJECTIVE Our study was conducted to validate the Japanese version of the Ford Insomnia Response to Stress Test (FIRST-J) and to clarify the association of the measure with trait anxiety and insomnia in healthy subjects and insomnia patients. METHODS We studied 161 healthy subjects and 177 insomnia patients who completed the FIRST-J, Pittsburgh Sleep Quality Index (PSQI), Athens Insomnia Scale (AIS), and State-Trait Anxiety Inventory-Trait (STAI). The healthy subjects and the insomnia patients were classified, respectively, into two groups with high FIRST-J and low FIRST-J scores (divided by the median value of healthy subjects). RESULTS Cronbach α coefficients of the FIRST-J in the insomnia patients and healthy subjects were 0.89 and 0.87, respectively. Factor analysis revealed that the FIRST-J had a single-factor structure. The FIRST-J score significantly correlated with all other measures in the healthy subjects, though the score only correlated with the score of the STAI in the insomnia patients. The healthy subjects with high FIRST-J scores showed higher scores of the AIS and STAI than those with low FIRST-J scores. Furthermore, insomnia patients had a higher total score of the FIRST-J than the healthy subjects. CONCLUSIONS The FIRST-J is an important tool for assessing vulnerability to insomnia.

A two-year follow-up study on the symptoms of sleep disturbances/insomnia and their effects on daytime functioning

OBJECTIVE This study attempts to identify changes in the symptoms of sleep disturbances/insomnia over a two-year course and their effects on daytime functioning. METHODS We administered two population-based epidemiological surveys in 2005 and 2007 to participants from rural Japan. RESULTS In the first survey, 30.7% of the subjects reported sleep disturbances/insomnia. Among them, 60.9% reported sleep problems at the two-year follow-up. A comparison of sleep disturbances/insomnia, and subjective daytime functioning measures between the new incident cases and persistent poor sleepers revealed that the total score of persistent poor sleepers was significantly lower than that of new incident cases on the Pittsburgh Sleep Quality Index and physical quality of life (QoL) but not mental QoL. Longitudinal comparisons of the symptoms of sleep disturbances/insomnia in persistent poor sleepers revealed that sleep efficiency was significantly worse at follow-up. Exacerbation of the symptoms of sleep disturbances/insomnia at follow-up was observed in mild but not severe cases. CONCLUSIONS Sleep efficiency progressively worsens over time, and physical QoL can deteriorate as sleep disturbances/insomnia become chronic. Since the symptoms of sleep disturbances/insomnia and their daytime effects are exacerbated even in mild cases, early intervention and treatment are necessary.

Clinical significance of periodic leg movements during sleep in rapid eye movement sleep behavior disorder

The aim of the study was to explore the clinical significance of periodic leg movements during sleep (PLMS) in rapid eye movement sleep behavior disorder (RBD) and the pathological relation between these two disorders. Eighty-one consecutive idiopathic RBD (iRBD) patients, classified into two groups—27 patients with PLMS (iRBD–PLMS) and 54 patients without PLMS (iRBD w/o PLMS), and 31 patients with idiopathic PLMS (iPLMS)—were enrolled in this study. Descriptive variables including Epworth Sleepiness Scale (ESS) scores and polysomnography measures were compared among the three patient groups. Correlation analysis between the ratio of PLMS-related arousal index to PLMS index (PLMAI/PLMI) and sleep stage-related variables or clinically descriptive RBD variables was performed in the iRBD–PLMS group. Associated factors indicating the existence of PLMS during both stages NREM and REM were investigated in this group with clinically descriptive RBD variables. The iRBD–PLMS group showed a significantly lower ESS score and PLMAI/PLMI than the iPLMS group. The PLMAI/PLMI value negatively correlated with RWA/REM. RWA/REM was extracted as a factor that was significantly associated with the existence of PLMS during both stages NREM and REM. The RBD morbidity duration appeared as an associated factor for PLMS only during stage REM among the iRBD patients. In iRBD patients, daytime sleepiness remains modest probably because of suppressed cortical reactivity to PLMS. Increased PLMS activity during both stages NREM and REM is related to the mechanism of REM atonia loss caused by brainstem dysfunction. Especially, PLMS during stage REM might reflect the length of RBD morbidity.