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Biomedical subjects

J Hasan

Publications and source records attributed to J Hasan.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of nasal CPAP treatment on plasma volume, aldosterone and 24-h blood pressure in obstructive sleep apnoea.

Polycythaemia, peripheral oedema formation and hypertension have classically been described in association with obstructive sleep apnoea (OSA). However, there is very limited information about blood volume in OSA and how it changes during long-term treatment with nasal continuous positive airway pressure (nCPAP). Plasma (PV) and red-cell volumes (RCV), 24-h ambulatory blood pressure (BP), 24-h natriuresis and morning plasma aldosterone, renin activity and atrial natriuretic peptide in 11 men with a mean age of 47 y (range 37-55), apnoea index (AI) of 55 (22-106), body mass index of 36 (30-43) and seated BP of > or = 140/90 mmHg without any medication were measured. BP-measurements were repeated after 3 weeks and all measurements after 3 mo of nCPAP treatment. Aldosterone and 24-h mean heart rates decreased during treatment. Twenty-four-h BP decreased after 3 weeks but that decrease did not persist after 3 mo of treatment. There was a relationship between changes in night-time mean BP and PV and aldosterone. The haematocrit declined in every patient. No significant changes were found in the mean PV or RCV. They were in all instances lower than has earlier been described for normal, non-obese subjects. These data also suggest that OSA causes divergent individual disturbances in blood volume homeostasis which can be corrected by nCPAP.

Adult↗
PubMed1996

Past and future of computer-assisted sleep analysis and drowsiness assessment.

The development of computerized sleep analysis has been very much technology-driven by both mathematical tools and available hardware but, additionally and unfortunately, by the almost-30-year-old standard used for manual sleep stage scoring of paper recordings. There are no technical restrictions in terms of computing power, storage space, and costs anymore. However, the standards of visual sleep stage scoring have proven insufficient and ambiguous, and their utilization evidently provides misleading and erroneous information. The low temporal resolution provided by the one-page epoch, the crude division of the sleep processes into a few discrete stages, and the total ignorance of spatial information are the major drawbacks. It is meaningless to try to improve the computerised systems if the algorithms are based on erroneous concepts. Instead, the focus should be changed to studies dealing with the identification and modelling of true biological sleep-related processes. This work cannot be performed without the successful application of computerized methods, some of which have been used in related fields but have not yet been applied to sleep studies. It is extremely important that basic findings are confirmed with a wide variety of methods in several laboratories. The use of predetermined, fixed criteria for methods, waveforms, and states too early is scientifically erroneous and hazardous. Instead standards should describe the minimum requirements for the recording and analysis of the signals in terms of sampling rate, dynamic range, linearity, and documentation of the methods used. With the development of better technology, these standards ought to be constantly reevaluated and modified. The development toward more open commercial digital systems, including standardized programming methods and data formats, would have great positive impact to the field. These trends have long been established in many other fields of industry.

Algorithms↗
PubMed1996

Role of weaning in the nutritional status of infant--a longitudinal study in the rural area of Aligarh.

Influences of weaning practices on nutritional status were studied in a cohort of 200 infants over a period of one year in the rural area of Aligarh. Weaning was late in most of the infants under study. The nutritional status of infants up to 6 months was significantly better than that of infants more than 6 months of age. Most of them used the family-type food as weaning food.

Developing Countries↗
PubMed1995

Multi-centre comparison of five eye movement detection algorithms.

Although various investigators have suggested algorithms for the automatic detection of eye movements during sleep, objective comparisons of the proposed methods have previously been difficult due to different recording arrangements of different investigators. In this study the results of five eye movement detection algorithms applied to the same data were compared to visually scored data. The percentages of true and false detections are given for various threshold levels in rapid and slow eye movement detections. The methods gave best results when they were used with the same electrode montage they were designed for but the performance decreased when other montages were used. Subtracting the cross-talk of EEG delta activity improved the correctness of eye movement detections.

Journal Article↗
PubMed1995

Quantitative topographic electroencephalographic mapping during drowsiness and sleep onset.

The topographic EEG features of drowsiness and sleep onset are much less well documented than are their temporal aspects. A commercial topographical mapping system was used to assess the main EEG features employing all 19 international 10/20 system electrode sites referenced to linked ears during wakefulness, stages 1A and 1B drowsiness, stage 2 sleep, and sleep onset REM periods in 19 patients. All patients had been referred for a diagnostic EEG or a Multiple Sleep Latency Test and had essentially normal EEGs. Anterior alpha of drowsiness seldom represented frontal spread of the occipital alpha rhythm but usually was a distinct activity of apparent separate origin. Theta activities of drowsiness were maximum at CZ and FZ. Vertex sharp waves and sawtooth waves of rapid eye movement (REM) sleep had similar fields maximum at the midline with a steep decrease laterally. Isolated anterior mainly negative waves were identified. Sleep spindles were usually maximal in fronto central, occasionally centro parietal, or even parietal areas.

Adolescent↗
PubMed1994

The relationship between EEG delta activity and autonomic activity as measured by SCSB during daytime sleep.

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.

Journal Article↗
PubMed1994

Natural evolution of snoring: a 5-year follow-up study.

INTRODUCTION: The natural evolution of snoring was studied in a middle-aged population in Finland. MATERIAL AND METHODS: A questionnaire was mailed to a stratified random sample of 1600 people aged 36-50 years in 1985 with a response rate of 75.2%; 53% of them completed also the 5-year-follow-up questionnaire. Clinical examinations (N = 36) and whole-night polygraphic recordings (N = 22) were made to habitual (every or almost every night) snorers and daily sleepy persons. RESULTS: A total of 626 persons completed the 5-year-follow-up questionnaire. The prevalence of habitual snoring among men was 28.3-43.8% and among women 6.3-18.8%, increasing with age. Sleepiness was common: doze-off at the wheel was reported by 23% of snorers and traffic accidents because of sleepiness by 4.5%. Hypertension was clearly more common (p = 0.002) among habitual snorers, but the self-reported rates of strokes and coronary heart disease were not increased in this study. None of the snorers had been investigated because of their snoring or sleepiness during the five years. In polygraphic recordings 11/22 showed an oxygen desaturation index (ODI4) more than 5/h; active treatment was started for 8 of them. The observed prevalence of sleep apnea syndrome with ODI4 > 10 was 1.1% in this study. CONCLUSIONS: Snorers, even with clear sleepiness, are passive in seeking help for their symptoms. Physicians should actively diagnose this treatable condition impairing the quality of life and increasing the risk of traffic accidents and vascular diseases.

Accidents, Traffic↗
PubMed1994

A new method to study blood pressure, heart rate and EEG as a function of reaction time.

A new method is presented to study the relationship between reaction time and blood pressure, heart rate and EEG. The method consists of a simultaneous recording of continuous invasive or non-invasive arterial blood pressure, ECG, EEG, EMG and EOG in a sound-isolated chamber while a monotonous visual reaction time test is running for about 90 minutes. The signals are A/D-converted and analyzed digitally after recording. One second average amplitudes are computed. Systolic, mean and diastolic blood pressure values are calculated, and the EEG is divided into the delta, theta, alpha, sigma and beta frequency bands. The signal amplitudes are averaged in three different reaction time categories, i.e., when the reaction is normal, delayed or missing. Preliminary tests suggest that interesting differences can be observed in the studied variables in different reaction time classes. This method can also be applied to the investigation of autonomic control and to treatment studies.

Blood Pressure↗
PubMed1993

The effect of small differences in electrode position on EOG signals: application to vigilance studies.

The primary aim of the study was to determine the best electrode positions for EOG signals in vigilance studies. Two-channel recordings were conducted in analogy to the Rechtschaffen and Kales (1968) system. Twenty electrodes (10 electrode pairs) were compared. Both EOG amplitudes and amplitude asymmetries within an electrode pair were studied. The amplitude of the EOG signal is sensitive to relatively small differences in electrode position. This concerns especially distance from the eye, the direction of eye movement and the effect of the upper eye lid movement. Larger and more symmetrical EOG amplitudes were obtained for different eye movements by placing the electrodes more medially than in the conventionally used system. EOG asymmetry in different electrode positions was dependent on the eye movement direction and even on the starting and end points of a movement with equal angular degrees. Most of the data could be explained by a simple monopolar model when combined with the effects of the upper eye lid movements. The most unexpected finding was that the EOG amplitudes of the horizontal and oblique eye movements were significantly larger when the eyes were moving towards an electrode than when they were moving to the opposite direction.

Adult↗
PubMed1993

Validation of computer analysed polygraphic patterns during drowsiness and sleep onset.

A computer system for the automatic analysis of polygraphic records was validated. Records from 9 subjects made during routine MSLT tests were analysed both by two preliminary and one consensus scorer and by a computer system. Special attention was paid to the analysis of drowsiness periods. Therefore a classification system including 7 stages, three for wakefulness and movement, one for drowsiness and three for the sleep stages S1, S2 and SREM was used. Adaptive segmentation was used to divide the records into short segments of variable length (mean 1.6 sec, range 0.5-13.7 sec). The agreements between the computer and visual scores were relatively good for 5 subjects having a prominent occipital alpha activity during wakefulness (range 70-79%) but less promising (range 64-70%) for the other 4 subjects with "poor" occipital alpha activity. The values obtained corresponded to the inter-scorer agreements. Most of the discrepancies were between adjacent stages. At times in the presence of strongly fluctuating EEG amplitudes and especially with the "low-alpha" subjects it was very difficult to determine exactly even by visual scoring when, for instance, drowsiness became sleep. It is concluded that the reliability of the system is sufficient for practical purposes especially if critical parts of the records are visually reexamined. It was found to be difficult to define unambiguous scoring criteria for subjects with poorly defined EEG rhythms giving insufficient landmarks for stage determination.

Adult↗
PubMed1992

Daytime sleepiness: a risk factor in community life.

The prevalence of daytime sleepiness and background factors associated with it were investigated in a study carried out at the UKK Institute. The inquiry took the form of a questionnaire mailed to 1600 people of middle age. Daytime sleepiness was found to be associated with disturbed night sleep. Women were more tired than men, but men slept more frequently during the day. Those suffering from tiredness complained of poor health more than other respondents. Traffic accidents and other mishaps attributable to tiredness had occurred in 1.3% of cases, and almost 5% of male respondents had dozed off while driving at least five times in their lives. The findings indicate a need for increased attention to disturbance of sleep and daytime sleepiness in routine health screening.

Accidents, Traffic↗
PubMed1988

Self-evaluations of factors promoting and disturbing sleep: an epidemiological survey in Finland.

The purpose of this epidemiological survey (N = 1600) was to describe the factors which middle-aged urban people in Finland perceived as promoting or disturbing sleep. The response rate was 75%. The results suggested that quality of sleep is determined by numerous factors; social and psychological factors, health status, external sleeping conditions, life style and living habits. Every third respondent felt that exercise had a positive impact on sleep. Second in importance were reading and listening to music. Furthermore, sauna, shower and bath, stability in life, psychological factors, positive experience in work, satisfactory sexual life and good and quiet sleeping environment were reported to have positive effects on sleep. Men considered work-related pressure and fatigue (20%) as the most important factor disturbing falling asleep or quality of sleep. In women's ranking work problems appeared no sooner than in the third place. Women reported worries, interpersonal problems, and marital and family discord as the most disturbing factors to sleep (37%). Coffee in the evening had a negative effect on falling asleep. Although a 'nightcap' was considered to improve relaxation on falling sleep, men ranked alcohol as the fourth disturbing factor. Other disturbing factors were stress, irregularities in everyday life because of social events, travelling or atypical catnaps. Eating and exercising too heavily or too late in the evening were found to disturb sleep. On the other hand, temporary lack of exercise seemed to impair the quality of sleep. As external factors disturbing sleep the subjects considered noise light, too high room temperature, tight clothing, unfamiliar sleeping environment and restless children.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Occupational class, physical workload, and musculoskeletal morbidity in the engineering industry.

In 1973, 502 employees in three metal industry plants, stratified by age, sex, and occupational class, were examined for physical workload by interview and observation at the workplace and for musculoskeletal disorders by questionnaire, interview, and clinical examination. Five years later, 88% of the sample were re-examined for their musculoskeletal status. The work of the blue collar groups was heavier as measured by indices of physical work load based on the observation and interview (physical strain, physical load, static phases, and stereotypy). Rheumatic symptoms, clinical findings in the musculoskeletal system, and chronic musculoskeletal diseases were more frequent in both female and male blue collar workers than in the respective white collar groups on the first occasion and the increase in morbidity during follow up was higher in the blue collar groups. At an individual level within the blue collar class, however, associations between indices of physical workload and musculoskeletal morbidity were weak or non-existent. The associations were weakened by selective movement of people with musculoskeletal disorders from heavy jobs to premature retirement or to lighter jobs. Physical strain and physical load were negatively associated with the incidence of long term musculoskeletal disorders in the female blue collar group.

Bone Diseases↗
PubMed1988

Epidemiology of exercise effects on sleep.

This survey was designed to study the characteristics of sleep and perceived factors promoting and disturbing sleep. Several living habits, such as exercise, and characteristics of sleep were investigated independently of each other by a pretested questionnaire and a sleep diary which were mailed to a stratified random sample of 200 men and women in each of the age groups 36, 41, 46 and 50 years (N = 1600). The response rate was 75%. Every third respondent felt that exercise (e.g. jogging and evening walks) had a positive impact on sleep quality. The most frequently perceived positive effects of exercise were ease of falling asleep, deepness of sleep, a sense of wellbeing and more alertness in the morning. Negative perceived effects of exercise were uncommon. The balance of positive and negative perceived effects of exercise was more favourable when the activity was performed early in the evening compared to late at night. When both the intensity and the timing of exercise were considered, light and moderate exercise, especially early in the evening, had mainly positive effects on sleep. The frequency of negative impacts increased when the exercise was performed vigorously late at night. However, a considerable portion of vigorous late exercisers reported mainly positive effects. The available information suggests that especially light and moderate exercise early in the evening should be emphasised in health education as a means to enhance sleep and to improve its quality. However, the epidemiological information about exercise and sleep should be investigated and verified in detail using objective methods and controlled interventions.

Adult↗