Mina Kobayashi

The REM sleep behavior disorder screening questionnaire: validation study of a Japanese version.

BACKGROUND REM sleep behavior disorder (RBD) is a parasomnia characterized by intermittent loss of normal skeletal muscle atonia during REM sleep and elaborate motor activity associated with dream mentation. Idiopathic RBD (iRBD) has a known association with neurodegenerative diseases such as synucleinopathies. Recently, a specific screening scale for assessment of REM sleep behavior disorder (RBDSQ) was validated. Detection of RBD using a Japanese version of the RBDSQ would be useful in the stepwise diagnostic process. We investigated the validity and reliability of a Japanese version of this instrument, the RBDSQ-J. METHODS Subjects were 52 patients with iRBD diagnosed according to criteria in the International Classification of sleep disorders, second edition, 55 obstructive sleep apnea syndrome (OSAS) patients who responded well to CPAP therapy after a diagnosis of RBD was ruled out by history and polysomnography (PSG) and 65 healthy subjects. RESULTS An RBDSQ-J score cut-off of 5.0 was considered useful for differentiating the iRBD group from the healthy subjects or the OSAS group. Cronbachs alpha for the entire RBDSQ-J was 0.866. CONCLUSION The RBDSQ-J had high sensitivity, specificity, and reliability and would be applicable as a screening method for iRBD in the elderly Japanese population.

Quality of life in patients with narcolepsy with cataplexy, narcolepsy without cataplexy, and idiopathic hypersomnia without long sleep time: Comparison between patients on psychostimulants, drug-naïve patients and the general Japanese population

OBJECTIVE To assess the quality of life of patients with narcolepsy with cataplexy (NA-CA), narcolepsy without cataplexy (NA w/o CA), and idiopathic hypersomnia without long sleep time (IHS w/o LST) who were taking psychostimulant medication, and to ascertain which factors (including psychosocial and environmental variables) influence quality of life in this population. METHODS In total, 185 patients who had received regular treatment were enrolled in the study (NA-CA, n=83; NA w/o CA, n=48; IHS w/o LST, n=54). Patients were asked to complete questionnaires including the Short Form-36 Health Survey (SF-36), the Epworth Sleepiness Scale (ESS), and items concerning psychosocial and environmental variables. RESULTS All three diagnostic groups had significantly lower scores for most SF-36 domains compared with the Japanese normative data, and the ESS score was significantly reduced with treatment. Multiple logistic regression analyses revealed that several SF-36 domains were associated with the ESS score; autonomy in controlling own job schedule, experience of divorce or break up with a partner due to symptoms, experience of being forced to relocate or being dismissed due to symptoms, and perception of support from others. CONCLUSIONS The severity of subjective sleepiness and psychological and environmental variables influenced quality of life in patients with these hypersomnias of central origin.

Development and validation of the Japanese version of the Athens Insomnia Scale

The aim of this study was to develop and validate a Japanese version of the Athens Insomnia Scale (AIS‐J).

Characteristics of obstructive sleep apnea in patients with Parkinson's disease

Parkinsons disease (PD) patients frequently develop obstructive sleep apnea (OSA). In order to clarify the clinical significance of OSA in PD, we compared descriptive variables between PD patients with OSA (PD+OSA) and without (PD-OSA), and between the PD+OSA group and a group of OSA patients without PD (control OSA). The apnea hypopnea index (AHI) cutoff of 15 episodes/hour on polysomnogram (PSG) was used to assign 107 PD patients to groups; OSA-related symptoms and PSG findings were then compared. Demographic and PSG variables were compared between PD+OSA patients and 31 OSA controls. Twenty-four patients with PD (22.4%) were classified as PD+OSA. There were no significant differences in descriptive variables between the PD+OSA and PD-OSA groups. The PD+OSA group had a higher arousal index on PSG than the PD-OSA group, although the two groups had similar ESS scores. The PD+OSA patients had a lower respiratory arousal index and a smaller decrease in oxygen saturation than the control OSA group, despite having a similar AHI. The prevalence of OSA in PD did not differ from that in the general elderly population, indicating that the clinical significance of OSA as a contributor to daytime sleepiness in PD is low.

Clinical Characteristics in Two Subgroups of Obstructive Sleep Apnea Syndrome in the Elderly: Comparison Between Cases With Elderly and Middle-Age Onset

BACKGROUND Morbidity due to obstructive sleep apnea syndrome (OSAS) is increased in the elderly population. However, the clinical characteristics of OSAS in elderly patients have not been characterized conclusively. The aim of this study was to clarify differences in clinical characteristics of OSAS between patients with middle-age onset and elderly onset of OSAS. METHODS Patients with OSAS aged > or = 65 years were classified into groups according to age at first identification of respiratory pauses during sleep: a middle-age onset group (n = 32) where onset was at age < 50 years and an elderly onset group (n = 31) where onset was at age > or = 60 years. We compared demographic variables; polysomnographic variables; daytime sleepiness measures, including the multiple sleep latency test (MSLT) and the Epworth sleepiness scale (ESS); and adequate level of nasal continuous positive airway pressure (CPAP) between groups. RESULTS BMI and frequency of underlying cardiovascular disorder were lower in the elderly onset group than in the middle-age onset group. No significant differences in apnea-hypopnea index or percentage of the period showing O(2) desaturation were seen between groups. However, arousal index, maximal negative esophageal pressure value, and adequate nasal CPAP level were significantly smaller in the elderly onset group. Mean sleep latency on MSLT was longer, and ESS score was lower in the elderly onset group. CONCLUSIONS Compared with the middle-age onset group, the clinical significance of OSAS in the elderly onset group seemed to remain milder. This finding is possibly because of the smaller physiologic response to respiratory events.

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.

Selection of response criteria affects the success rate of oral appliance treatment for obstructive sleep apnea.

BACKGROUND In oral appliance therapy for obstructive sleep apnea (OSA), treatment success is arbitrarily defined. We investigated if the selection of response criteria affected the success rate of oral appliance treatment. METHODS The effects of an oral appliance on apnea-hypopnea index (AHI) and nadir percutaneous oxygen saturation (SpO2) were investigated in 224 OSA patients. Treatment success was defined as a reduction in AHI to <5 events per hour with a >50% reduction in baseline AHI (criterion 1), a follow-up AHI of <10 events per hour with a >50% reduction in baseline AHI (criterion 2), a >50% reduction in baseline AHI alone (criterion 3), or a >50% reduction in baseline AHI with the nadir SpO2 above 90% (criterion 4). RESULTS The baseline AHI was reduced with an oral appliance in place compared with the follow-up value (23 ± 11-8.5 ± 8.7 events/h; P<.05) in all of the participants. In every OSA subgroup, the success rate under criterion 3 (75% [mild], 71% [moderate], and 70% [severe]) was greater than that under criterion 1 (53%, 40%, and 24%, respectively). However, responders under criterion 3 in the severe OSA subgroup were still hypoxemic with a nadir SpO2 of 87 ± 8% even after treatment. This situation was improved by the use of criterion 4, in which a satisfactory improvement in AHI (from 38 ± 11 to 1 ± 1 events/h; P<.01) was associated with a sufficient increase in the nadir SpO2 (93 ± 2%). CONCLUSIONS We conclude that the selection of response criteria influences the success rate of oral appliance treatment. To avoid adverse health outcomes, an adjunct definition of treatment success using SpO2 may be effective for patients who have more severe OSA.

The validity of the PAM-RL device for evaluating periodic limb movements in sleep and an investigation on night-to-night variability of periodic limb movements during sleep in patients with restless legs syndrome or periodic limb movement disorder using this system

BACKGROUND The status of night-to-night variability for periodic limb movements in sleep (PLMS) has not been clarified. With this in mind, we investigated the validity of PLMS measurement by actigraphy with the PAM-RL device in Japanese patients with suspected restless legs syndrome (RLS) or periodic limb movement disorder (PLMD) and the night-to-night variability of PLMS among the subjects. METHODS Forty-one subjects (mean age, 52.1±16.1 years) underwent polysomnography (PSG) and PAM-RL measurement simultaneously. Thereafter, subjects used the PAM-RL at home on four more consecutive nights. RESULTS The correlation between PLMS index on PSG (PLMSI-PSG) and PLM index on PAM-RL (PLMI-PAM) was 0.781 (P<.001). When the PLMSI cutoff value on PSG was set at 15 episodes per hour, the cutoff value for predicting this PLMSI level was 16.0 episodes per hour. When the condition was set to the level in which the mean interclass correlation coefficient reached ≥0.9, the number of required nights for repeated measurements was 26 nights for subjects with PLMI of <15 episodes per hour and three nights for those with PLMI ≥15 episodes per hour on PAM-RL. CONCLUSIONS PAM-RL is thought to be valuable for assessing PLMS even in Japanese subjects. Recording of PAM-RL for three or more consecutive nights may be required to ensure the screening reliability of a patient with suspected pathologically frequent PLMS.

Principal Component Analysis of Multimodal Neuromelanin MRI and Dopamine Transporter PET Data Provides a Specific Metric for the Nigral Dopaminergic Neuronal Density

The loss of dopaminergic (DA) neurons in the substantia nigra (SN) is a major pathophysiological feature of patients with Parkinsons disease (PD). As nigral DA neurons contain both neuromelanin (NM) and dopamine transporter (DAT), decreased intensities in both NM-sensitive MRI and DAT PET reflect decreased DA neuronal density. This study demonstrates that a more specific metric for the nigral DA neuronal density can be derived with multimodal MRI and PET. Participants were 11 clinically diagnosed PD patients and 10 age and gender matched healthy controls (HCs). Two quantities, the NM-related index (RNM) and the binding potential of the radiotracer [18F]FE-PE2I to DAT (BPND) in SN, were measured for each subject using MRI and PET, respectively. Principal component analysis (PCA) was applied to the multimodal data set to estimate principal components. One of the components, PCP, corresponds to a basis vector oriented in a direction where both BPND and RNM increase. The ability of BPND, RNM and PCP to discriminate between HC and PD groups was compared. Correlation analyses between the motor score of the unified Parkinsons disease rating scale and each metric were also performed. PCP, BPND and RNM for PD patients were significantly lower than those for HCs (F = 16.26, P<0.001; F = 6.05, P = 0.008; F = 7.31, P = 0.034, respectively). The differential diagnostic performance between the HC and PD groups as assessed by the area under the receiver-operating characteristic curve was best for PCP (0.94, 95% CI: 0.66–1.00). A significant negative correlation was found between the motor severity score and PCp (R = -0.70, P<0.001) and RNM (R = -0.52, P = 0.015), but not for BPND (R = -0.36, P = 0.110). PCA of multimodal NM-sensitive MRI and DAT PET data provides a metric for nigral DA neuronal density that will help illuminate the pathophysiology of PD in SN. Further studies are required to explore whether PCA is useful for other parkinsonian syndromes.

A preliminary study on the relationships between diurnal melatonin secretion profile and sleep variables in patients emergently admitted to the coronary care unit

To clarify the significance of melatonin secretion under intensive care conditions, we investigated melatonin secretion profiles and sleep parameters of 23 patients just after admission to the coronary care unit (CCU) and 19 age-matched controls. Sleep parameters were evaluated by actigraphy, and melatonin secretion was assessed by measuring the urinary 6-sulphatoxy melatonin (6-SMT). 6-SMT secretion was lower and nocturnal sleep parameters were less satisfactory in the subjects than those in the controls, and there were positive correlations between these variables, particularly in the subject patients. The lowered melatonin secretion might be involved in the mechanism of insomnia in CCU patients.