Kazuyoshi Namba

Clinical characteristics of restless legs syndrome in end-stage renal failure and idiopathic RLS patients.

This study was done to identify the clinical characteristics of uremic restless legs syndrome (RLS). Consecutive uremic RLS patients (n = 15) and idiopathic RLS patients (iRLS; n = 20) were evaluated. The groups were compared with respect to their clinical course, subjective symptoms [using the Pittsburgh Sleep Quality Index (PSQI) and the International Restless Legs Syndrome Severity Scale (IRLS)], polysomnographic (PSG) variables, the results of the suggested immobilization test (SIT), and the drug doses used to treat RLS. The duration of the disorder was significantly shorter in the uremic RLS group than in the iRLS group. The PSQI and IRLS scores before treatment were higher in the uremic RLS group than in the iRLS group. The periodic leg movement index (PLM index) on PSG and the SIT index were also higher in the uremic RLS group (P < 0.001, respectively). The bromocriptine equivalent dose of dopaminergic agonists used to treat RLS was significantly higher in the uremic RLS group (P < 0.001). Uremic RLS appears to deteriorate faster and to become more severe than iRLS. Moreover, uremic RLS patients appear to have a decreased response to dopaminergic agonists.

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).

Gender Differences in the Clinical Characteristics Among Japanese Patients With Obstructive Sleep Apnea Syndrome

BACKGROUND Gender differences in the prevalence of various manifestations of obstructive sleep apnea syndrome (OSAS) is not as great as previously believed. The aim of the present study was to clarify the clinical patient characteristics of Japanese women and men with OSAS. METHODS A cross-sectional case-match control study was performed on patients from two sleep disorder centers. Two hundred forty-five women with OSAS were classified into premenopausal (n = 70) and postmenopausal (n = 175) groups. As well, 245 men matched for both age and apnea-hypopnea index (AHI) and another 245 men matched for age and body mass index (BMI) were established. We compared descriptive variables between genders in both the premenopausal and the postmenopausal female patient groups. RESULTS As a whole, female patients had significantly higher BMI than AHI-matched male patients (p < 0.05) and a significantly lower value of AHI than BMI-matched male patients (p < 0.001). Female patients had lower Epworth Sleepiness Scale scores than BMI-matched male patients (p < 0.05). On logistic regression analysis, presence of hypertension was significantly associated with BMI (>or=25 kg/m(2)), AHI (>or= 15 to < 30 events/h; >or= 30 to < 60 events/h; >or= 60 events/h), and presence of both hyperlipidemia and diabetes mellitus. However, gender differences were not associated with the occurrence of hypertension. Female patients had significantly lower optimal levels of continuous positive airway pressure than male patients. CONCLUSIONS Our results suggest that both the OSAS severity and the strength of pharyngeal closure is less in Japanese female patients than in male patients. Moreover, Japanese female patients are thought to have less daytime sleepiness than male patients but a similar rate of hypertension as male patients.

Excessive Daytime Sleepiness among Japanese Public Transportation Drivers Engaged in Shiftwork

Objective: To explore the actual condition of sleep disorders underlying subjective excessive daytime sleepiness (EDS) among train and bus drivers engaged in shiftwork. Methods: This study targeted 3109 public transportation drivers. Clinical diagnoses were made based on 147 drivers who claimed to have subjective EDS, and 285 drivers who were judged to have obstructive sleep apnea syndrome (OSAS), based on the screening process. Results: Among these subjects, the prevalence of OSAS was 3.7% and that of shiftwork disorder (SWD) was 1.5%. SWD was common among drivers who had EDS (32.7% of drivers with EDS), and their EDS severity was higher than that of OSAS drivers. The drivers with SWD were mostly young and neither obese nor hypertensive. Conclusions: Encouraging awareness of SWD and OSAS could be necessary to prevent sleepiness-related accidents.

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.

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.

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.

Clinical significance of upper airway obstruction pattern during apneic episodes on ultrafast dynamic magnetic resonance imaging.

OBJECTIVES In order to assess the relationship between upper airway obstruction pattern and the clinical characteristics of obstructive sleep apnea syndrome (OSAS), we evaluated dynamic changes in the pharyngeal airway of patients with the disorder by using ultrafast dynamic magnetic resonance imaging (MRI). METHODS MRI while asleep was performed on 31 patients with OSAS (29 men, 2 women; mean age, 46.6+/-8.2 years; mean body mass index, 26.7+/-4.9kg/m(2); mean AHI, 40.6+/-21.7episodes/h). Relationships between obstruction pattern focusing on differences between single-site obstruction (SO) and multiple-site obstructions (MO) and titrated value of nasal CPAP in addition to respiratory variables were investigated. RESULTS The velopharynx (VP) was the main obstructive site among most of the cases with SO (17 of 18 cases), and all of the cases with MO (n=13) showed obstruction at and below the VP. AHI was significantly higher in cases with MO than in those with SO (P<0.01). As for SaO(2) variables, minimum value during sleep was significantly lower and total time with SaO(2) pound90% was longer in cases with MO than in those with SO (P<0.05 each). Titrated value of n-CPAP was also significantly higher in cases with MO than in cases with SO (P<0.05). CONCLUSIONS Our results strongly suggest that formation of MO manifested on ultrafast dynamic MRI could be related to increased severity of the disorder. Considering the higher titrable value of CPAP, MO could be brought about by high pharyngeal pressure.

Changes in cerebral hemoglobin indices in obstructive sleep apnea syndrome with nasal continuous positive airway pressure treatment

IntroductionThis study examined both the relationship between the changes in the brain tissue hemoglobin indices and SpO2 during sleep in patients with obstructive sleep apnea syndrome (OSAS) and the effect of nasal continuous positive airway pressure (CPAP) treatment on hemoglobin indices.Materials and methodsPolysomnographic recordings and near-infrared spectroscopy (NIRS) were performed during an afternoon nap on 15 OSAS patients before treatment and 12 healthy controls. Oxyhemoglobin (HbO), deoxyhemoglobin (HbD), and total hemoglobin (HbT) on NIRS were analyzed, and the correlation of these variables and peripheral arterial oxygen saturation (SpO2) were investigated in the OSAS group before nasal CPAP treatment. In nine OSAS patients, the recordings were also compared between the condition with and without using CPAP.ResultsHbO decreased during obstructive respiratory events while HbT and HbD showed adverse increases, and the values of these hemoglobin indices returned to the baseline values at the end of each respiratory event in the OSAS group. The fluctuations in these cerebral hemoglobin indices during sleep were significantly larger in the OSAS group than in the control group. Moreover, in the OSAS group, these changes correlated strongly with the change in SpO2. When using CPAP, not only respiratory events but also the fluctuations in both the cerebral hemoglobin indices and SpO2 were almost completely suppressed.ConclusionArterial oxygen desaturation is clearly related to cerebral oxygenation, and fluctuations of hemoglobin indices can be suppressed with CPAP.

Change in frequency of periodic limb movements during sleep with usage of continuous positive airway pressure in obstructive sleep apnea syndrome

Periodic limb movements during sleep (PLMS) sometimes newly appear on the night of continuous positive airway pressure (CPAP) titration in patients with obstructive sleep apnea syndrome (OSAS). To ascertain the incidence and causative factors of this phenomenon, we investigated differences in its prevalence and the factors associated with newly appeared and persistent PLMS on CPAP titration night. We retrospectively analyzed polysomnographic data of 997 consecutive OSAS outpatients who had undergone overnight CPAP titration. On the basis of changes in periodic limb movements index (PLMI) values (cut off level≥15/h) from baseline polysomnography (BPSG) to CPAP titration PSG, patients were assigned to one of four groups: persistent, CPAP-emergent, CPAP-disappeared, and non-PLMS. The rate of patients was 6.7% in the persistent group, 8.0% in the CPAP-emergent group, 4.0% in the CPAP-disappearance group, and 81.2% in the non-PLMS group. Multivariate logistic regression analysis revealed that a higher apnea-hypopnea index (AHI) on BPSG and ≥47years of age appeared to be associated with the CPAP-emergent group. The results suggest that elderly patients with higher AHI at BPSG may present with CPAP-emergent PLMS.