Fraction of apnea is associated with the required continuous positive airway pressure level and reflects upper airway collapsibility in patients with obstructive sleep apnea.

STUDY OBJECTIVES: We aimed to determine whether the fraction of apnea (Fapnea) could be used as an alternative index to reflect upper airway collapsibility. METHODS: We retrospectively recruited 161 patients (16 women, mean age 47.8 years, body mass index [BMI] 28.0 kg/m2, and apnea-hypopnea index 46.4 events/h) with moderate to severe obstructive sleep apnea who had undergone nasal continuous positive airway pressure (CPAP) titration. Fapnea is defined as the percentage of apneic events relative to the total number of apneic and hypopneic events during sleep in a supine position on diagnostic polysomnography. We randomly split the data (70/30) into the development and validation datasets. In the development dataset, we conducted a multiple regression analysis to assess the association of variables, including age, sex, BMI, supine rapid eye movement (REM) sleep apnea-hypopnea index, and apnea with a CPAP level during supine REM sleep (REM_CPAP). Moreover, we developed an equation for predicting the CPAP level. Thereafter, we evaluated the correlation between the actual CPAP level and the value calculated using the model. RESULTS: BMI and Fapnea were the only significant factors that predicted the REM_CPAP level (adjusted r = .60, P < .001) in the development dataset. The validation data revealed a significant correlation between the actual and predicted CPAP levels (r = .69, P < .0001). We observed similar associations during supine non-REM sleep. CONCLUSIONS: Fapnea could significantly predict the CPAP levels during both REM and non-REM sleep, which likely reflects the upper airway collapsibility, independent of the BMI. CITATION: Nakayama H, Takei Y, Kobayashi M, Yanagihara M, Inoue Y. Fraction of apnea is associated with the required continuous positive airway pressure level and reflects upper airway collapsibility in patients with obstructive sleep apnea. J Clin Sleep Med. 2022;18(5):1243-1249.

Development and validation of the Benzodiazepine Hypnotics Withdrawal Symptom Scale (BHWSS) based on item response theory.

This study aimed to refine and validate the Benzodiazepine Hypnotics Withdrawal Symptom Scale (BHWSS). The 12-item prototype version of the BHWSS was administered to a sample of 346 patients with chronic insomnia (161 males and 185 females, mean age: 52.8 ± 16.6 years) who had been taking hypnotics (benzodiazepines [BZDs] or BZD receptor agonists) for at least 3 months. The item information curve indicated that two of the 12 BHWSS items should be excluded. As a result of analyzing the 10-item version of the BHWSS (revised-BHWSS), the contribution rate in the case of the factor 1 was 0.49, Cronbach's α was 0.90, and the reliability coefficient ω was 0.91. An analysis of the item information curve for the revised-BHWSS indicated that the information amount per item increased from 3.90 for the original 12-item BHWSS to 4.37 for the 10-item revised-BHWSS. The receiver operating characteristic curve indicated that 6.5 points on the revised-BHWSS was the most appropriate cutoff for estimating moderate or severe withdrawal symptoms using the Benzodiazepine Dependence Self-Report Questionnaire as a reference. These results suggest that the 10-item revised-BHWSS has sufficient reliability and validity for evaluating the severity of withdrawal symptoms after discontinuing BZDs.

Reliability and validity of the Japanese version of the Biological Rhythms Interview of assessment in neuropsychiatry-self report for delayed sleep-wake phase disorder.

OBJECTIVE: The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) might be applicable for assessing delayed sleep-wake phase disorder (DSWPD). We aimed to investigate the reliability and validity of the Japanese version of the BRIAN self-report (J-BRIAN-SR) in DSWPD patients and determine a cutoff score to identify the presence of the disorder. METHODS: We enrolled 60 newly diagnosed DSWPD outpatients and 64 age-matched healthy controls. We used Cronbach's alpha for internal reliability to evaluate J-BRIAN-SR. We confirmed the reliability of the A test and re-test using Pearson's correlation coefficient in the controls. We used confirmatory factor analysis to evaluate the factor structure of J-BRIAN-SR and referenced the Morningness-Eveningness Questionnaire (MEQ) to check concurrent validity. We analyzed the receiver operating characteristic curve (ROC) to determine the J-BRIAN-SR cutoff point for the presence of DSWPD. RESULTS: The 18-component scores of the J-BRIAN-SR had an overall reliability coefficient (Cronbach's alpha) of 0.82. We confirmed a high test-retest reliability using an intraclass correlation coefficient (r = 0.84). The correlation between J-BRIAN-SR and MEQ was 0.38 (p = 0.003). The J-BRIAN-SR that we extracted by exploratory factor analysis consisted of three factors. A score of 40 points provided a sensitivity of 80.0% and a specificity of 75.6% for the positivity of DSWPD. CONCLUSIONS: The results of the present study revealed that J-BRIAN-SR is a valid and reliable instrument for screening and evaluating the severity of DSWPD. Our findings will be useful to physicians and patients in Japan and those in clinical settings.

The efficacy of add-on ramelteon and subsequent dose reduction in benzodiazepine derivatives/Z-drugs for the treatment of sleep-related eating disorder and night eating syndrome: a retrospective analysis of consecutive patients.

STUDY OBJECTIVES: The objective of this study was to determine the efficacy of ramelteon in treating abnormal eating behavior in patients with sleep-related eating disorder and/or night eating syndrome. METHODS: We retrospectively reviewed the medical records of patients with sleep-related eating disorder/night eating syndrome at the Yoyogi Sleep Disorder Center from November 2013 to November 2018. We categorized patients as ramelteon treatment responders when the frequency of nighttime eating per week decreased to less than half of that before treatment. RESULTS: Forty-nine patients were included in the analysis. The mean frequency of eating behavior (per week) (standard deviation) at baseline and post-ramelteon treatment was significantly different, at 5.3 (2.2) and 3.2 (3.0), respectively (P < .001). Twenty-one patients (42.9%) were classified as responders. Adverse events, all of which were mild daytime somnolence, were observed in 5 patients. There were significantly more individuals using benzodiazepine derivatives and Z-drugs before treatment and those with coexisting delayed sleep-wake phase disorder in the responder group than in the nonresponder group (P < .001 and P < .05, respectively). The mean benzodiazepine derivatives and Z-drugs dose significantly decreased from baseline to post-ramelteon treatment within the responder group (P < .05). This trend was not observed in the nonresponder group. Meanwhile, the sleep midpoint of patients with sleep-related eating disorder/night eating syndrome and delayed sleep-wake phase disorder did not significantly change after treatment. CONCLUSIONS: Our results indicate that ramelteon is a candidate treatment for sleep-related eating disorder/night eating syndrome. The effects of ramelteon might have occurred primarily through the reduction in benzodiazepine derivatives and Z-drugs rather than through the improvement in sleep-wake rhythm dysregulation.

Pathological Features of Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats.

OBJECTIVE: The Spontaneously Diabetic Torii (SDT) fatty rat, established by introducing the fa allele (obesity gene) of the Zucker fatty rat into the SDT rat genome, is a new model of obese type 2 diabetes. We studied the pathologic features of diabetic retinopathy (DR) in this animal. METHODS: The eyes of SDT fatty, SDT (controls), and Sprague Dawley (SD) rats (normal controls) were enucleated at 8, 16, 24, 32, and 40 weeks of age (n = 5-6 for each rat type at each age). The retinal thicknesses, numbers of retinal folds, and choroidal thicknesses were evaluated. Immunostaining for glial fibrillary acidic protein (GFAP) and vascular endothelial growth factor (VEGF) was performed. Quantitative analyses of the immunopositive regions were performed using a cell-counting algorithm. RESULTS: The retinas tended to be thicker in the SDT fatty rats and SDT rats than in the SD rats; the choroids tended to be thicker in the SDT fatty rats than in the SD rats. The retinal folds in the SDT fatty rats developed earlier and were more severe than in the SDT rats. Quantitative analyses showed that the GFAP- and VEGF-positive regions in the retinas of the SDT fatty rats were significantly larger than those of the SDT rats. CONCLUSIONS: SDT fatty rats developed more severe DR earlier than the SDT rats. The SDT fatty rats might be useful as a type 2 diabetes animal model to study DR.

Obstructive sleep apnea phenotypes in men based on characteristics of respiratory events during polysomnography.

PURPOSE: The upper airway (UA) anatomical collapsibility, UA muscle responsiveness, breathing control, and/or arousability are important contributing factors for obstructive sleep apnea (OSA). Differences in clinical manifestations of OSA are believed to reflect interactions among these factors. We aimed to classify OSA patients into subgroups based on polysomnographic (PSG) variables using cluster analysis and assess each subgroup's characteristics. METHODS: Men with moderate or severe OSA and without any concomitant heart or psychosomatic disease were recruited. A hierarchical cluster analysis was performed using variables including fraction of apnea, respiratory event duration, minimum oxygen saturation, arousal rate before termination, and frequency of respiratory events in the supine position. The impact of sleep stages or body position on PSG variables was also evaluated in each cluster. RESULTS: A total of 210 men (mean age, 50.0 years, mean body mass index, 27.4 kg/m2) were studied. The three subgroups that emerged from the analysis were defined as follows: cluster 1 (high fraction of apnea and severe desaturation (20%)), cluster 2 (high fraction of apnea and long event duration (31%)), and cluster 3 (low fraction of apnea (49%)). There were differences in the body mass index and apnea type between the three clusters. Sleep stages and/or body position affected PSG variables in each cluster. CONCLUSIONS: Patients with OSA could be divided into three distinct subgroups based on PSG variables. This clustering may be used for assessing the pathophysiology of OSA to tailor individual treatment other than continuous positive airway pressure therapy.

Risk factors and clinical signs of severe Acanthamoeba keratitis.

PURPOSE: To determine risk factors and clinical signs for severe Acanthamoeba keratitis (AK) by comparing severe cases with mild cases with good prognosis. PATIENTS AND METHODS: We reviewed medical records of ten cases of AK (five males and five females) referred to our hospital and classified cases into two groups. One eye that required therapeutic keratoplasty and three eyes with a poor visual acuity (<0.2) on last visit were included in the severe group. Six eyes that had good prognosis with a visual acuity of 1.2 on last visit were classified as mild group. We compared patients' age, the time required for diagnosis, visual acuity on first visit, the history of steroid eye drops use, and other clinical findings. RESULTS: The average age of the severe group was older than the mild group (P=0.04). The duration between onset and diagnosis of AK and visual acuity on first visit was not statistically different. A history of steroid eye drop use was found in four eyes of the severe group (100%) and four eyes of the mild group (67%). Keratoprecipitates were found in all severe group eyes and one mild group eye during follow-up (P=0.01). One case in the severe group was diagnosed with diabetes mellitus at initial examination. We detected Staphylococcus epidermis by palpebral conjunctival culture in one case of the severe group. CONCLUSION: Aging may be a possible risk factor for severe AK. The presence of keratoprecipitates is a possible sign of severe AK. Attention is also required in patients with comorbidities such as diabetes mellitus and bacterial infection.

Validation of a sheet-shaped body vibrometer for screening of obstructive sleep apnea.

We assessed the validity of using a sheet-shaped body vibrometer (SBV) as a portable monitoring device for obstructive sleep apnea (OSA) screening. Seventy consecutive patients with suspected OSA underwent simultaneous in-laboratory polysomnography (PSG) and SBV. We evaluated the screening accuracy of the respiratory event index (REI) obtained with the SBV, using the REI based on either the estimated total sleep time (REI_eTST) or time in bed (REI_TIB); these were compared to the apnea-hypopnea index (AHI) obtained via PSG. Bland-Altman plots indicated that the mean difference between REI_eTST and AHI was lower than that between REI_TIB and AHI (1.2 ± 19.8 vs. 6.5 ± 16.8). For AHI ≥ 15, the sensitivity and specificity at an optimal REI_eTST of 17.0 were 90.9% and 76.9%, whereas those at an optimal REI_TIB of 15.9 were 86.4% and 80.8%, respectively; moreover, for AHI ≥ 30, these values at an optimal REI_eTST of 26.0 were 89.5% and 88.2%, whereas those at an optimal REI_TIB of 23.8 were 84.2% and 92.2%, respectively. The optimal cutoff values of REIs for AHI of ≥ 5 were markedly different from those for AHI obtained via PSG (REI_eTST, 14.9; REI_TIB, 15.0), but close to those for AHI of ≥ 15; both had good sensitivities and specificities. REIs obtained via SBV performed well in moderate-to-severe, but not mild, OSA screening; REI_eTST showed a slightly higher sensitivity and a relatively closer value to the AHI obtained via PSG when compared to REI_TIB. We consider the SBV less acceptable for screening mild cases than more severe cases.

Restless legs syndrome augmentation among Japanese patients receiving pramipexole therapy: Rate and risk factors in a retrospective study.

To investigate the rate of and risk factors for restless legs syndrome (RLS) augmentation in Japanese patients receiving pramipexole (PPX) treatment. Records of 231 consecutive patients with idiopathic RLS who received PPX therapy for more than one month in a single sleep disorder center were analyzed retrospectively. Augmentation was diagnosed based on the Max Planck Institute criteria; associated factors were identified by logistic regression analysis. Mean age at PPX initiation was 60.6 ± 14.9 years and mean treatment duration was 48.5 ± 26.4 months. Augmentation was diagnosed in 21 patients (9.1%). Daily PPX dose and treatment duration were significantly associated with augmentation. By analyzing the receiver operating characteristic curve, a PPX dose of 0.375 mg/day was found to be the optimal cut-off value for predicting augmentation. After stratifying patients according to PPX treatment duration, at median treatment duration of 46 months, optimal cut-off values for daily doses were 0.375 and 0.500 mg/day for <46 months and ≥46 months of treatment, respectively. The RLS augmentation with PPX treatment in Japanese patients was occurred at rate of 9.1%, being quite compatible with previously reported rates in Caucasian patients. The symptom could appear within a relatively short period after starting the treatment in possibly vulnerable cases even with a smaller drug dose. Our results support the importance of keeping doses of PPX low throughout the RLS treatment course to prevent augmentation.

Mandibular Advancement Device as a Comparable Treatment to Nasal Continuous Positive Airway Pressure for Positional Obstructive Sleep Apnea.

STUDY OBJECTIVES: Positional obstructive sleep apnea (P-OSA) is a clinically common phenotype of OSA, which can be treated effectively with mandibular advancement devices (MADs). We hypothesized that the efficacy of an MAD is comparable to that of nasal continuous positive airway pressure (nCPAP) in P-OSA patients. METHODS: Among patients diagnosed with OSA at a single sleep center from January 2008 to May 2014, male subjects with moderate OSA were recruited and stringently categorized as having P-OSA when the ratio of their lateral apnea-hypopnea index (AHI) to supine AHI was ≤ 0.5, their lateral sleep time was > 60 minutes, and their lateral REM sleep time was longer than 10 minutes. Treatment efficacy was compared between P-OSA subjects with an MAD (n = 34) and those with nCPAP (n = 34) after matching for age, body-mass index, and baseline AHI. RESULTS: There were no significant differences in baseline AHI (MAD: nCPAP = 20.6 ± 3.9/h: 21.3 ± 1.7/h, p = 0.35) or in follow-up AHI (MAD: nCPAP = 4.7 ± 3.5/h: 3.4 ± 3.7/h, p = 0.12) between the 2 treatment groups, and hence MADs lowered the AHI to the same extent as nCPAP. CONCLUSIONS: These findings suggest that an MAD is as efficacious as nCPAP for P-OSA patients. MAD treatment for this specific phenotype may be a promising patient-tailored and first-line approach to OSA. COMMENTARY: A commentary on this article appears in this issue on page 1079.

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 Parkinson's 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 Parkinson's 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.

Progression of obstructive sleep apnoea syndrome in Japanese patients.

PURPOSE: The aggravation of obstructive sleep apnoea syndrome (OSAS) is reportedly associated with weight gain. The present study investigated the factors associated with worsening of respiratory functional parameters in Japanese OSAS patients who showed no body weight change during the follow-up period. METHODS: A follow-up polysomnography (PSG) was performed in 82 patients with a mean of 7.5 years after the diagnostic PSG, and the apnoea-hypopnoea index (AHI), respiratory event duration, minimum percutaneous oxygen saturation (SpO2), baseline SpO2, and 3 % oxygen desaturation index (ODI) during sleep were compared between the two PSGs. Furthermore, factors associated with worsened AHI, respiratory event duration, and minimum SpO2 were investigated using logistic regression analysis. RESULTS: No significant differences were observed in AHI, baseline SpO2, and 3 % ODI between the two PSGs. However, there was a significantly increased respiratory event duration and decreased minimum SpO2 observed. In addition, 17 patients had a ≥25 % AHI increase, and the age of 40-60 years and initial OSAS severity (mild and moderate) were the significantly associated factors. Age of ≥60 years and a baseline body mass index (BMI) of ≥25 kg/m(2) were significantly associated with prolonged respiratory event duration. The age of 40-60 years was significantly associated with decreased minimum SpO2. CONCLUSIONS: Untreated middle-aged patients may be at a high risk for worsened AHI and SpO2 even without weight gain.

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.

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.

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.

Daytime dysfunction in children with restless legs syndrome.

We investigated daytime dysfunction in children with restless legs syndrome (RLS) and the effects of treatment primarily with iron supplements on RLS symptoms and daytime dysfunction. We recruited 25 children with RLS (male:female=6:19, mean age at study onset: 12.3 years) for this prospective study, assessing their demographics, symptomatic characteristics, serum ferritin levels, and daytime functioning using the ADHD Rating Scale IV (ADHD-RS-IV), the Pediatric Symptom Checklist (PSC), and the Pediatric Quality of Life Inventory (PedsQL™). Children with RLS were compared with 28 controls (male:female=10:18, mean age: 13.2 years) on these measures, pre- and post-treatment. Before treatment, ADHD-RS-IV (all ps<0.05) and PSC scores (p<0.05) were significantly higher and PedsQL™ scores (all ps<0.05) significantly lower in the RLS group than in the control group. Eight and one of the RLS group had abnormally high PSC and ADHD-RS-IV scores, respectively. Following treatment, participants' daytime function had improved to levels similar to those of controls. Sixteen out of twenty-three cases were successfully treated primarily with iron supplement. Some children with RLS have daytime dysfunction; however, this can be treated with iron supplements.

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.

Factors associated with duration before receiving definitive diagnosis of narcolepsy among Japanese patients affected with the disorder.

BACKGROUND: Narcolepsy (NA) is a sleep disorder characterized by excessive daytime sleepiness and an increased propensity of rapid eye movement sleep. If left untreated, NA can lead to academic underachievement or job loss because of dozing off or mistakes caused by inattentiveness due to sleepiness. PURPOSE: Although untreated narcolepsy patients may suffer from many social disadvantages due to excessive daytime sleepiness, mostly it takes a long time to receive a definitive diagnosis of the disorder. This retrospective study investigated factors related to the period until definitive diagnosis among patients with narcolepsy in Japan. METHODS: We enrolled 181 consecutive patients (108 men, 73 women; mean age 37.6 ± 16.6 years old; narcolepsy with cataplexy/narcolepsy without cataplexy = 131:50). Multivariate logistic regression analysis was performed with period until definitive diagnosis as the dependent variable and descriptive clinical variables as the independent variables. RESULTS: The mean period until receiving the diagnosis among the participants was 9.9 ± 10.1 years. More than half of the patients first learned about the disorder from information provided by the media. Multivariate logistic analysis indicated that adult onset (p < 0.01), onset in 1995 or later (p < 0.001), and first learning about the disorder from a sleep disorder specialist physician or a general practitioner (p < 0.001) were associated with a time taken for receiving a definitive diagnosis less than or equal to the median value (7 years). CONCLUSION: Improving access to information about the concept of the disorder and the medical institutions specialized in sleep disorders, especially via the Internet, would be necessary to promote early diagnosis of the disorder.

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

AIM: The aim of this study was to develop and validate a Japanese version of the Athens Insomnia Scale (AIS-J). METHODS: The AIS-J was created using a back-translation design. A total of 477 outpatients with chronic insomnia and 163 individuals from the general community were recruited. Participants were asked to complete the AIS-J along with two other insomnia scales - Japanese versions of the Pittsburgh Sleep Quality Index and the Insomnia Severity Index. RESULTS: The AIS-J consisted of a two-factor structure: 'nocturnal sleep problem' (items 1-5) and 'daytime dysfunction' (items 6-8). Internal consistencycoefficients ranged from 0.78 to 0.88. Correlations between the AIS-J and the aforementioned authorized scales were 0.81 and 0.85, respectively. Scores on the AIS-J were significantly higher for the insomnia group than for the control group. The AIS-J cut-off value for identifying pathological insomnia was estimated at 6 points or more, and the AIS-J-nocturnal cut-off value was estimated at 4 points or more. CONCLUSIONS: The AIS-J has sufficient validity and diagnostic utility.

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

Parkinson's 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.