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Adami AM, Pavel M, Hayes TL, Singer CM. Detection of movement in bed using unobtrusive load cell sensors. ACTA ACUST UNITED AC 2009; 14:481-90. [PMID: 19171523 DOI: 10.1109/titb.2008.2010701] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Quality of sleep is an important attribute of an individual's health state and its assessment is therefore a useful diagnostic feature. Changes in the patterns of motor activities during sleep can be a disease marker, or can reflect various abnormal physiological and neurological conditions. Presently, there are no convenient, unobtrusive ways to assess quality of sleep outside of a clinic. This paper describes a system for unobtrusive detection of movement in bed that uses load cells installed at the corners of a bed. The system focuses on identifying when a movement occurs based on the forces sensed by the load cells. The movement detection approach estimates the energy in each load cell signal over short segments to capture the variations caused by movement. The accuracy of the detector is evaluated using data collected in the laboratory. The detector is capable of detecting voluntary movements in bed while the subjects were awake, with an average equal error rate of 3.22% (+/-0.54). Its performance is invariant with respect to the individual's characteristics, e.g., weight, as well as those of the bed. The simplicity of the resulting algorithms and their relative insensitivity to the weight and height of the monitored individual make the approach practical and easily deployable in residential and clinical settings.
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Affiliation(s)
- Adriana M Adami
- Oregon Health and Science University, Portland, OR 97239, USA.
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2
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Rauhala E, Virkkala J, Himanen SL. Periodic limb movement screening as an additional feature of Emfit sensor in sleep-disordered breathing studies. J Neurosci Methods 2008; 178:157-61. [PMID: 19100767 DOI: 10.1016/j.jneumeth.2008.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 11/20/2008] [Accepted: 11/22/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND The standard method for recording periodic limb movements is anterior tibialis electromyography (EMG) but other methods are also used. A new movement sensor Emfit (ElectroMechanical Film) provides information about sleep-disordered breathing but also shows movements in bed. The aim of the study was to investigate the usability of a small Emfit sensor in revealing periodic movements. METHODS Twenty seven consecutive patients were studied. Periodic movements in EMG and Emfit were scored blindly and periodic leg movement index (PLMI) for EMG and periodic movement index (PMI) for Emfit were counted. Spearman's correlation coefficient was used to assess the relationship between Emfit data and EMG results. Sensitivities and specificities were computed for PLMI and PMI levels of 5 and 15 movements/h. Additionally, receiver operating characteristic (ROC) curves were derived and the area under the curve (AUC) was calculated. RESULTS The Spearman's correlation coefficient between the PMI of Emfit and the PLMI of EMG was 0.87. The sensitivity of the Emfit sensor to detect periodic limb movements was 0.91 at the level of 5 movements/h and 0.73 when the cut-off level was 15 movements/h. The specificities were 0.75 and 1.00, respectively. AUC in ROC analysis was 0.96 and 0.98 in the levels of 5 and 15 movements/h. CONCLUSIONS The results suggest that the Emfit sensor might be suitable for screening of periodic limb movements even if the sensor is placed under the thoracic area of the patient in sleep-disordered breathing studies.
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Affiliation(s)
- Esa Rauhala
- Department of Clinical Neurophysiology, Medical Imaging Centre, Pirkanmaa Hospital District, Tampere, Finland.
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3
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Abstract
In order to investigate how the duration of actigraphic recordings affects the reliability of actigraphic estimates of sleep and 24-h activity rhythm variables, two to 3 weeks of actigraphy were recorded, from which pairs of variables derived from two periods of increasing length (1-10 days) were compared. Two groups were studied: (1) 10 subjects suffering from primary insomnia; and (2) 12 demented elderly subjects living semi-independently in group care facilities of homes for the elderly. Actigraphic estimates of primary measures of sleep (duration and efficiency) and of the 24-h activity pattern (interdaily stability, intradaily variability and amplitude) were calculated on variable lengths of the actigraphic recordings. The average absolute difference of two estimates decreased - and reliability increased - strongly with an increasing number of days analysed. An acceptable reliability of the interdaily stability estimate required more than 7 days of recording. It can be concluded that a valuable improvement in the reliability of actigraphic sleep estimates can be obtained by simply increasing the number of recording nights. The results support the importance of day-to-day variability in insomnia and dementia that has already been previously noted by others, and even suggest the presence of 'week-to-week' variability. This variability may have been involved in the equivocal results of treatment studies in insomnia and dementia where outcome measures were based on a limited number of nights. Such studies could profit from extension of the recording duration to, e.g. 2 weeks, and from the inclusion of variability measures as measures of clinical interest.
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Affiliation(s)
- Eus J W VAN Someren
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
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Kalleinen N, Polo O, Himanen SL, Joutsen A, Urrila AS, Polo-Kantola P. Sleep deprivation and hormone therapy in postmenopausal women. Sleep Med 2006; 7:436-47. [PMID: 16815746 DOI: 10.1016/j.sleep.2006.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 02/05/2006] [Accepted: 02/09/2006] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND PURPOSE Sleep complaints increase after menopause, but literature on the effect of postmenopausal hormone therapy (HT) on sleep is controversial. The purpose of this study was to determine the effect of ageing and HT on sleep quality, assessed using polysomnography, and on the accuracy of the subjective estimation of sleep quality in women before and after sleep deprivation. PATIENTS AND METHODS Twenty postmenopausal women (aged 58-72 years) were recruited: 10 HT-users and 10 non-HT-users. Eleven young women (aged 20-26 years) served as controls. Polysomnography and subjective sleep quality were measured on four consecutive nights: adaptation, baseline, 40-h sleep deprivation and recovery. RESULTS Although the postmenopausal women slept worse than the controls at baseline, and in particular during the recovery night, their recovery response to sleep deprivation was well preserved. At baseline, HT-users had a shorter latency to rapid eye movement (REM) (P=0.043), with fewer awakenings from slow wave sleep (SWS) (P=0.029) but more from REM (P=0.033) than non-HT-users. During recovery, the HT-users had more stage 2 sleep (P=0.048) and less slow wave activity (SWA) in the first non-rapid eye movement (NREM) sleep episode (P=0.021) than the non-HT-users. The poor correlation between subjective and objective sleep quality at baseline became significant during recovery. CONCLUSIONS Although sleep in postmenopausal women was worse than in young controls, the recovery response following sleep deprivation was relatively well preserved. HT offered no significant advantage to sleep at baseline and slightly weakened the recovery response to prolonged wakefulness.
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Affiliation(s)
- Nea Kalleinen
- Sleep Research Unit, Department of Physiology, University of Turku, Dentalia, Lemminkäisenkatu 2, Turku, Finland.
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Baddock SA, Galland BC, Beckers MGS, Taylor BJ, Bolton DPG. Bed-sharing and the infant's thermal environment in the home setting. Arch Dis Child 2004; 89:1111-6. [PMID: 15557043 PMCID: PMC1719737 DOI: 10.1136/adc.2003.048082] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To study bed-sharing and cot-sleeping infants in the natural setting of their own home in order to identify differences in the thermal characteristics of the two sleep situations and their potential hazards. METHODS Forty routine bed-sharing infants and 40 routine cot-sleeping infants aged 5-27 weeks were individually matched between groups for age and season. Overnight video and physiological data of bed-share infants and cot-sleeping infants were recorded in the infants' own homes including rectal, shin, and ambient temperature. RESULTS The mean rectal temperature two hours after sleep onset for bed-share infants was 36.79 degrees C and for cot-sleeping infants, 36.75 degrees C (difference 0.05 degrees C, 95% CI -0.03 to 0.14). The rate of change thereafter was higher in the bed-share group than in the cot group (0.04 degrees C v 0.03 degrees C/h, difference 0.01, 0.00 to 0.02). Bed-share infants had a higher shin temperature at two hours (35.43 v 34.60 degrees C, difference 0.83, 0.18 to 1.49) and a higher rate of change (0.04 v -0.10 degrees C/h, difference 0.13, 0.08 to 0.19). Bed-sharing infants had more bedding. Face covering events were more common and bed-share infants woke and fed more frequently than cot infants (mean wake times/night: 4.6 v 2.5). CONCLUSIONS Bed-share infants experience warmer thermal conditions than those of cot-sleeping infants, but are able to maintain adequate thermoregulation to maintain a normal core temperature.
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Affiliation(s)
- S A Baddock
- Department of Women's & Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
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Abstract
We evaluated the performance of the static-charge-sensitive bed (SCSB), a non-invasive movement sensor, in detecting nocturnal periodic movement activity using simultaneous bilateral anterior tibialis electromyography (EMGat) as a reference. Two different study setups were used, one with 500 random record extracts, another with 10 continuous recordings. The inter-rater reliability between two independent scorers was 0.92 in scoring EMGat and 0.91 in scoring SCSB. In an epoch based analysis, depending on the study setup and scorer, the sensitivity of the SCSB to detect periodic leg movements was 0.81-0.94 whereas the specificity was 0.84-0.89. In a movement-by-movement analysis, despite incomplete concordance between the two methods the total number of movements per hour were comparable. Our findings support the use of the SCSB as a non-invasive alternative to anterior tibialis EMG recordings to reveal the presence of nocturnal periodic movement activity and estimate its frequency.
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Affiliation(s)
- E Rauhala
- Department of Physiology, University of Turku, Finland
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Abstract
Nocturnal motor activity was examined in long-term rehabilitation patients complaining of poor sleep and having fibromyalgia syndrome (N = 24) or other musculoskeletal disorders (N = 60) and compared with that in 91 healthy controls drawn from a random community sample. Self-reports on sleep complaints and habits were collected. The frequency of nocturnal body movements, the "apnoea" index and ratio of "quiet sleep" to total time in bed were measured using the Static Charge Sensitive Bed (SCSB) (BioMatt). As a group, patients with fibromyalgia syndrome did not differ from patients with other musculoskeletal disorders or from healthy controls in their nocturnal motor activity. The "apnoea" index was a little higher in the fibromyalgia group than in the healthy control group but did not differ from that of the group of other musculoskeletal patients. Further multivariate analyses adjusted for age, BMI, medication and "apnoea" index did not support the assumption that an increased nocturnal motor activity characterizes patients with fibromyalgia syndrome.
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Affiliation(s)
- M T Hyyppä
- Social Insurance Institution, Turku, Finland
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Härmä M, Suvanto S, Partinen M. The effect of four-day round trip flights over 10 time zones on the sleep-wakefulness patterns of airline flight attendants. ERGONOMICS 1994; 37:1461-1478. [PMID: 7957024 DOI: 10.1080/00140139408964926] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To study the effect of a four-day-round trip flight on the sleep-wakefulness of airline flight attendants, subjective sleep-wakefulness and autonomic sleep phases were measured. Forty flight attendants (mean age 33 years, range 21-50) kept daily logs on sleepiness, the time when going to bed, and sleep quality. In addition, the autonomic sleep phases of 21 subjects were studied by the static charge sensitive bed (SCSB) method. After the westward flight, the subjects went to bed approximately 1-3 h local time earlier during the first few days and were very sleepy compared to the week before the flight. There was a significant increase in the number of awakenings and in the feeling of 'not being at all rested' in the mornings. After the return flight eastwards, the subjects were very sleepy on the first evening but slept rather well for about 11 h. During the three following days, sleep restlessness, difficulties in falling asleep, and the feelings of sleepiness in the mornings increased compared to the week before the flights. Four days after the return flight, sleep length and the quality of sleep were, on average, the same as before the flights. According to the SCSB method, there were only small changes in the autonomic sleep phases due to the flights. After the westward flight, quiet sleep increased and intermediate sleep decreased compared to the sleep before the flight. The results indicate that most flight attendants have significant disturbances in sleep quality after transmedian flights. Sleep disturbances increase after both westward and eastward transmedian flights, but differ from each other in specific features.
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Affiliation(s)
- M Härmä
- Department of Physiology, Finnish Institute of Occupational Health, Vantaa
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Pulli K, Härmä M, Hasan J, Värri A, Loula P. The relationship between EEG delta activity and autonomic activity as measured by SCSB during daytime sleep. J Sleep Res 1994; 3:106-110. [PMID: 10607114 DOI: 10.1111/j.1365-2869.1994.tb00113.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of the present work was to study the applicability of the static-charge-sensitive bed (SCSB) method to sleep studies, by comparing autonomic nervous activity measured with the SCSB and EEG delta activity (0.5-2 Hz). Simultaneous polygraphic and SCSB measurements of the first sleep cycle (110 min) were recorded from seven subjects. The amount of delta activity filtered from the EEG was compared in 3 min epochs to an autonomic activity index (AAI) based on cardiac, respiratory and body movement activity. Individual Spearman rank order correlation coefficients between delta amplitude and the AAI varied from 0.17 to -0.60. Therefore, it is concluded that the relationship between the delta activity and the AAI is not systematic enough for defining 'depth' of sleep at any point in time by using the AAI. However, on average, the SCSB differentiates high and low delta values quite well. With some further improvement of the scoring system the SCSB is a useful tool in comparative sleep studies.
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Affiliation(s)
- K Pulli
- Institute of Occupational Health, Department of Physiology, Vantaa, Finland
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Hilakivi I, Alihanka J, Airikkala P, Laitinen LA. Alertness and sleep in young men during military service. Acta Neurol Scand 1992; 86:616-21. [PMID: 1481649 DOI: 10.1111/j.1600-0404.1992.tb05498.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Alertness and sleep in healthy young men conscripted into military service were examined by testing personality characteristics and by completing questionnaires at the beginning of military service about their civilian life alertness and sleep, and by using polygraphic recordings during their military service. Sleep-time during service was restricted to 8 hours a night; 236 men answered the questionnaire on civilian life alertness and sleep; 116 men a Minnesota multiphasic personality inventory; 7 underwent conventional, and 29 static charge-sensitive bed sleep recordings. Daytime latencies to Stage 2 sleep were 11 +/- 2 min. Sleep latencies were the shortest 6 h after waking. Night sleep was normal in conventional recordings. Nocturnal activities in static charge-sensitive bed recordings were: motor-active waking 4 +/- 3%, active sleep 24 +/- 11%, intermediate sleep 22 +/- 8%, quiet sleep 47 +/- 13%, and undefined 4 +/- 2%. Positive answers to questions on civilian life sleepiness were related to high scores on scales for hypochondria, psychasthenia and sense of reality, and night sleep longer than 10 h to high scores for psychasthenia and sense of reality, but not to polygraphic measures. Two men with complaints about civil-time irresistible sleep at the time of beginning the military service had short Stage 2 latencies at the daytime minimum of alertness during service (4 and 8 min). Although alertness and sleep during military service were normal on average, the findings suggest that all conscripted individuals may not have had enough sleep.
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Affiliation(s)
- I Hilakivi
- Department of Physiology, Faculty of Medicine, University of Helsinki, Finland
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Abstract
OBJECTIVE Our goal was to study the sleep quality in women with preeclampsia with a special reference to nocturnal body movement activity. STUDY DESIGN Sleep quality was evaluated in nine women with preeclampsia and eight women with normal term pregnancy by means of questionnaires and by recording the nocturnal body movement activity with the static charge-sensitive bed. RESULTS Subjective sleep complaints were similar in both groups. The total movement time and the total frequency of body movements in bed were, however, significantly increased in the preeclamptic group. CONCLUSION The study suggests that sleep is impaired in preeclamptic subjects.
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Affiliation(s)
- E M Ekholm
- Cardiorespiratory Research Unit, University of Turku, Finland
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Lauerma H, Lehtinen I, Lehtinen P, Korkeila JA, Toivonen S, Vaahtoranta K, Holmström R. Laterality of motor activity during normal and disturbed sleep. Biol Psychiatry 1992; 32:191-4. [PMID: 1420632 DOI: 10.1016/0006-3223(92)90023-s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- H Lauerma
- Psychiatric Clinic, University of Turku, Finland
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Partinen M, Telakivi T, Kaukiainen A, Salmi T, Färkkilä M, Saijonmaa O, Fyhrquist F. Atrial natriuretic peptide in habitual snorers. Ann Med 1991; 23:147-51. [PMID: 1829903 DOI: 10.3109/07853899109148039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We studied nocturnal and early morning variations in the concentration of plasma atrial natriuretic peptide (ANP) in 17 men who habitually snored. The subjects had a mean age of 51.0 +/- 5.8 years, range 41-62 y with a mean body mass index (BMI) of 32.9 +/- 7.3 kg/m2. The concentration of plasma ANP was measured by radioimmunoassay of venous samples at 10 p.m., midnight, 6 p.m. and 8 p.m. All night sleep recordings were conducted with the static charge sensitive bed to monitor body and breathing movements and a BIOX III Pulse Oximeter for the blood oxygen saturation level. Nine patients were defined as having the obstructive sleep apnea syndrome (OSAS). No significant diurnal variation for ANP concentrations was detected. At 8 a.m. five OSAS patients and two others had ANP concentrations above normal (70 pg/ml). Neither mean oxygen saturation during the night nor arterial hypertension discriminated between the high and low ANP groups at 8 a.m. The best discriminators for a high concentration of ANP at 8 p.m. were marked obesity (BMI greater than or equal to 30 kg/m2), over 400 movements lasting less than five seconds, and over 30% of active sleep per night. In a multivariate regression analysis age, percentage of active sleep during the night, BMI and the median oxygen saturation level during the night explained 76.4% of the total variance of ANP at 8 a.m. In a similar analysis the median oxygen saturation level during the night and BMI both explained the variance of ANP significantly. The whole model explained 53.7% of the variance of the ANP concentrations at 6 a.m.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Partinen
- Department of Neurology, Helsinki University Central Hospital, Finland
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Hyyppä MT, Lindholm T, Kronholm E, Lehtinen V. Functional insomnia in relation to alexithymic features and cortisol hypersecretion in a community sample. ACTA ACUST UNITED AC 1990. [DOI: 10.1002/smi.2460060406] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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