Piezoelectric rubber sheet sensor: a promising tool for home sleep apnea testing.

PURPOSE: This study aimed to develop an unobtrusive method for home sleep apnea testing (HSAT) utilizing micromotion signals obtained by a piezoelectric rubber sheet sensor. METHODS: Algorithms were designated to extract respiratory and ballistocardiogram components from micromotion signals and to detect respiratory events as the characteristic separation of the fast envelope of the respiration component from the slow envelope. In 78 adults with diagnosed or suspected sleep apnea, micromotion signal was recorded with a piezoelectric rubber sheet sensor placed beneath the bedsheet during polysomnography. In a half of the subjects, the algorithms were optimized to calculate respiratory event index (REI), estimating apnea-hypopnea index (AHI). In the other half of subjects, the performance of REI in classifying sleep apnea severity was evaluated. Additionally, the predictive value of the frequency of cyclic variation in heart rate (Fcv) obtained from the ballistocardiogram was assessed. RESULTS: In the training group, the optimized REI showed a strong correlation with the AHI (r = 0.93). Using the optimal cutoff of REI ≥ 14/h, subjects with an AHI ≥ 15 were identified with 77.8% sensitivity and 90.5% specificity. When applying this REI to the test group, it correlated closely with the AHI (r = 0.92) and identified subjects with an AHI ≥ 15 with 87.5% sensitivity and 91.3% specificity. While Fcv showed a modest correlation with AHI (r = 0.46 and 0.66 in the training and test groups), it lacked independent predictive power for AHI. CONCLUSION: The analysis of respiratory component of micromotion using piezoelectric rubber sheet sensors presents a promising approach for HSAT, providing a practical and effective means of estimating sleep apnea severity.

Quantitative detection of sleep apnea with wearable watch device.

The spread of wearable watch devices with photoplethysmography (PPG) sensors has made it possible to use continuous pulse wave data during daily life. We examined if PPG pulse wave data can be used to detect sleep apnea, a common but underdiagnosed health problem associated with impaired quality of life and increased cardiovascular risk. In 41 patients undergoing diagnostic polysomnography (PSG) for sleep apnea, PPG was recorded simultaneously with a wearable watch device. The pulse interval data were analyzed by an automated algorithm called auto-correlated wave detection with adaptive threshold (ACAT) which was developed for electrocardiogram (ECG) to detect the cyclic variation of heart rate (CVHR), a characteristic heart rate pattern accompanying sleep apnea episodes. The median (IQR) apnea-hypopnea index (AHI) was 17.2 (4.4-28.4) and 22 (54%) subjects had AHI ≥15. The hourly frequency of CVHR (Fcv) detected by the ACAT algorithm closely correlated with AHI (r = 0.81), while none of the time-domain, frequency-domain, or non-linear indices of pulse interval variability showed significant correlation. The Fcv was greater in subjects with AHI ≥15 (19.6 ± 12.3 /h) than in those with AHI <15 (6.4 ± 4.6 /h), and was able to discriminate them with 82% sensitivity, 89% specificity, and 85% accuracy. The classification performance was comparable to that obtained when the ACAT algorithm was applied to ECG R-R intervals during the PSG. The analysis of wearable watch PPG by the ACAT algorithm could be used for the quantitative screening of sleep apnea.

[Multiple sleep latency test, maintenance of wakefulness test and suggestive immobilization test].

In clinical practice, assessment usually involves self-report; however, objective measures are available. The multiple sleep latency test(MSLT) is performed during the main period of wakefulness and is designed to determine a patient's propensity to fall asleep. To be valid, the MSLT should be performed the day after nocturnal polysomnography (PSG). It is the standard test for the assessment of objective sleepiness and diagnosis of narcolepsy, that is a mean sleep latency equal to or under 8 minutes and equal to or greater than two sleep onset REM periods (SOREMPs). As opposed to the MSLT, the maintenance of wakefulness test (MWT) is designed to test the patient's ability to stay awake. The MWT is a 40-minutes protocol consisting of four trials separated by 2-hour intervals and is performed in much the same way as the MSLT. The MWT may be indicated in assessment of individuals in whom the inability to remain awake constitutes a safety issue, or in patients with narcolepsy or idiopathic hypersomnia to assess response to treatment with medications. There is little evidence linking mean sleep latency on the MWT with risk of accidents in real world circumstances. The suggestive immobilization test(SIT) was designed during which sensor and motor symptoms of restless legs syndrome are quantified during a period of immobility taking place in the evening before PSG. The patient is instructed to avoid moving voluntary for the entire duration of the test, which is designed to last 1 hour. The subjective leg discomfort evaluation and periodic leg movement by surface electromyograms from right and left anterior tibialis support diagnosis for restless legs syndrome. Many factors, such as clinical setting, pretest condition or aging effects etc. can alter the findings of the test and considerable clinical judgment is needed to avoid an error in interpretation. Above those three sleep-wake related tests provide us useful information.

[Chronic renal failure (hemo-dialysis patients)].

The feature of a dialysis patient's sleep disorder is that deviation with a feeling of subjective sleep and an objective sleep disturbance is large, and subjective symptoms are scarce considering serious sleep disorders. The feature of a dialysis patient' s sleep disturbance is characterized by increase in time to awake on bed and the fragmentation of sleep, which lead to reduction in sleeping hours. The prevalence of SAS (sleep apnea syndrome) in the dialysis patient is several times higher compared with the commoner. The prevalence of RLS (restless legs syndrome) in Japanese dialysis patient was almost even with Westerners patient. Otherwise it tends to underestimate sleep disturbance, our questionary survey revealed high prevalence of subjective sleep complaints in dialysis patients. The realities of dialyzed patient' s sleep disturbance might be more serious than we think.

Effect of intermittent systemic corticosteroid on bone metabolism in bronchial asthma patients.

The purpose of this study was to assess the effect on bone mineral density (BMD) of systemic corticosteroid (SCS) intermittently administered for rescue from asthmatic exacerbation. Through digital image processing and calculation of four other indices, BMD was compared in groups of asthmatic patients receiving inhaled corticosteroid (ICS) alone or ICS plus intermittent SCS. We defined SCS as intermittent administration of the equivalent of 1 mg/day prednisolone in the management of asthma exacerbations during the previous 1 year. Serum NTX, a bone resorption marker, was significantly higher (p = 0.02) in the SCS group than the ICS group. SCS had no effect on BMD, although the frequency of patients at "high-risk" for osteoporosis according to the Female Osteoporosis Self-assessment Tool for Asia (FOSTA) tended to be higher in the SCS group (35%) than in the ICS (28%) or control (10%) group. Because patients in the ICS group already had impaired respiratory function due to repeated asthma exacerbations, it was difficult to determine whether it was asthma itself or SCS that is the risk factor for osteoporosis. In addition, the response of biochemical markers of bone turnover to intermittent SCS remains unclear and likely differs from that elicited by high-dose, short-term, or continuous SCS. That said, relatively low-dose intermittent administration of SCS raised levels of bone resorption markers, which likely reflects altered bone metabolism. Taken together, these findings suggest that, without consideration of its effects on bone, SCS administration should be avoided.

The effect of acupuncture in the treatment of chronic obstructive pulmonary disease.

OBJECTIVE: Many claims have been made regarding the therapeutic efficacy of acupuncture. However, most controlled clinical studies have been limited to treatment of pain-related disorders and do not provide objective, quantifiable data for analysis. Traditional acupuncture has been applied to chronic obstructive pulmonary disease (COPD). However, only a few studies have been performed to determine the efficacy of this treatment. This study was conducted to determine whether a combination of traditional acupuncture treatment and conservative treatment for COPD improves dyspnea on exercise. METHODS: This was a prospective trial with matched-pair parallel groups of patients from the departments of respiratory internal medicine of Gifu University of Medicine, Meiji University of Oriental Medicine, and Gifu Red Cross Hospital, Japan. Thirty patients were divided into the acupuncture group (n = 15) and the control group (n = 15). The control group received conservative treatment with medication only. The acupuncture group received acupuncture treatments once a week for 10 weeks, in addition to conservative treatment with medication. The main outcome measure was the Modified Borg dyspnea scale after the 6-minute walk test. RESULTS: The acupuncture group had significantly better results on the Borg scale than the control group after 10 weeks (2.2 +/- 2.7 versus 6.4 +/- 3.4, p = 0.0001, 95% confidence interval, -5.10 to -2.35, paired t-test). The 6-minute walk distance and oxygen saturation at the minimum rate improved significantly in the acupuncture group compared with the control group. CONCLUSIONS: This study demonstrated that acupuncture contributed to the reduction of COPD-related dyspnea on exercise in 15 matched-pair parallel subjects.

Nocturia in men less than 50 years of age may be associated with obstructive sleep apnea syndrome.

OBJECTIVES: To assess the prevalence of nocturia in association with other voiding symptoms in men with obstructive sleep apnea syndrome (OSAS). METHODS: Seventy-three patients in whom OSAS was diagnosed at Gifu Red Cross Hospital during the period from October 2005 through April 2006 were assessed on the basis of the International Prostate Symptom Score (IPSS) and the Apnea-Hypopnea Index (AHI). Nocturia was defined as two or more voids per night. We classified patients by the presence versus absence of nocturia and by age (less than 50 years versus 50 years or more). Between-group differences in the AHI and IPSS were analyzed by Student's t test or the Mann-Whitney U test. RESULTS: Nocturia was found in 30 patients with OSAS (41.1%). The AHI was higher in patients with nocturia than in those without nocturia (P <0.01), especially in patients less than 50 years of age (P <0.005). However, other voiding symptoms were not associated with nocturia in the OSAS patients younger than 50 years. CONCLUSIONS: The prevalence of nocturia is high among patients with OSAS. Our results suggest that OSAS may have some relationship to nocturia without other voiding symptoms in men less than 50 years of age.

[A case of multiple systemic atrophy (MSA) analyzed by acoustic sound for nocturnal inspiratory stridor].

A 70-year old woman was admitted because of sleep maintenance insomnia with severe respiratory sounds during sleep. Polysomnography (PSG) revealed frequent respiratory events, particularly hypopneas, throughout the night associated with severe oxygen desaturation, and inspiratory stridor, which was shown to have a high-pitched frequency by acoustic sound analysis. She also presented fine finger tremor due to parkisonism, increased bilateral tendon responses, cerebellar ataxic gait, and dysautonomia. Therefore, we concluded that she suffered from multiple systemic atrophy (MSA). Nasal continuous positive airway pressure (nCPAP) treatment was successful. Characteristic PSG findings and analysing the snoring sound are important in the early diagnosis of sleep-related disordered breathing in MSA.

[A case of relapsed small-cell lung cancer successfully treated by administration of amrubicin].

Cardiotoxicity is a known adverse reaction of high cumulative doses of anthracycline drugs. We encountered a case successfully treated without myocardial disorder. A 54-year-old man who had been given a diagnosis of small-cell lung cancer (SCLC) (extensive disease) was treated with cisplatin (CDDP) plus irinotecan (CPT-11) as first-line chemotherapy, followed by amrubicin (AMR) (30 mg/m2) for 3 consecutive days against the relapsed SCLC. The cumulative dose reached 1110 mg/m2. This case report suggests that repeated treatment with AMR may be effective for relapsed SCLC.