bluuebunny/crossref_metadata_2025 huggingface dataset:
Three‐dimensional finite element analysis of the facial skeleton on simulated occlusal loading
Authors: Gross Martin D. , Arbel Gidon , Hershkovitz Israel
Published: March 2003

Development of predictive models of occlusal loading of the facial skeleton will be of value for prosthetic design in oral rehabilitation. A 3‐D finite element (FE) model of a human skull, based on CT scans, was constructed to analyse strain and stress distribution in the facial skeleton caused by simulated occlusal loading. Vertical loads were applied simulating loading of the full maxillary arch and unilateral single point occlusal loading of maxillary molar, pre‐molar, canine and incisor sites. Strain and stress regimes from Von Mises (VM) failure criteria and extension and compression diagrams showed even distribution of strain following loading of the full maxillary arch throughout the facial elements. For individual points, the highest VM concentrations were consistently located on the facial aspect several mm above the loading site. Strain trajectories divided into a ‘V‐shaped’ pattern, from the loading point into medial and lateral branches with higher VM values in the medial. As the same load was applied from the posterior to anterior region, VM values increased on all facial areas. Strain patterns were less symmetric and there was an increase in strain in the alveolar arch and around the rim of the nasal cavity. The overall picture of the facial skeleton is of a vertical plate enabling it to withstand occlusal stresses by in‐plane loading and bending in its own plane. The most efficient distribution of load was on maxillary full arch loading with the most unfavourable strain concentrations occurring on loading in the anterior region.
Investigation of mineral waters and soft drinks in relation to dental erosion
Authors: Parry J. , Shaw L. , Arnaud M. J. , Smith A. J.
Published: March 2003

A range of still and sparkling mineral waters were assessed for their erosive potential together with comparator soft drinks using in vitro dissolution assays with extracted human teeth and powdered hydroxyapatite. Dissolution levels with all of the mineral waters were very low and for several still waters were undetectable. Sparkling mineral waters showed slightly greater dissolution than still waters, but levels remained low and were of the order of one hundred times less than the comparator soft drinks. De‐gassing of a sparkling mineral water reduced its dissolution, but the total levels were still relatively low suggesting that carbonation of drinks may not be an important factor per se in respect of erosive potential. The complex and heterogeneous mineral compositions of mineral waters could influence the dissolution equilibrium of apatite in enamel and controlled addition of several ions to ultrapure deionized water was investigated. Calcium ions led to the greatest reduction in hydroxyapatite dissolution, but their effects were moderated by other ions including magnesium and sulphate. Thus, mineral waters appear to offer a safe alternative to more erosive acidic beverages and their complex mineral ion compositions may positively influence any dissolution processes at the tooth surface.
Bruxism is mainly regulated centrally, not peripherally
Authors: Lobbezoo F. , Naeije M.
Published: March 2003

Bruxism is a controversial phenomenon. Both its definition and the diagnostic procedure contribute to the fact that the literature about the aetiology of this disorder is difficult to interpret. There is, however, consensus about the multifactorial nature of the aetiology. Besides peripheral (morphological) factors, central (pathophysiological and psychological) factors can be distinguished. In the past, morphological factors, like occlusal discrepancies and the anatomy of the bony structures of the orofacial region, have been considered the main causative factors for bruxism. Nowadays, these factors play only a small role, if any. Recent focus is more on the pathophysiological factors. For example, bruxism has been suggested to be part of a sleep arousal response. In addition, bruxism appears to be modulated by various neurotransmitters in the central nervous system. More specifically, disturbances in the central dopaminergic system have been linked to bruxism. Further, factors like smoking, alcohol, drugs, diseases and trauma may be involved in the bruxism aetiology. Psychological factors like stress and personality are frequently mentioned in relation to bruxism as well. However, research to these factors comes to equivocal results and needs further attention. Taken all evidence together, bruxism appears to be mainly regulated centrally, not peripherally.
Use of optical coherence tomography for assessment of dental caries: quantitative procedure
Authors: Amaechi B. T. , Higham S. M. , Podoleanu A. GH. , Rogers J. A. , Jackson D. A.
Published: March 2003

A method for quantitative assessment of dental caries using optical coherence tomography (OCT) was demonstrated. Development of caries lesions in 15 bovine teeth, by demineralization in acidic buffer solution, was quantitatively assessed daily for 3 days, using OCT. An OCT system which can collect A‐scans (depth versus reflectivity curve), B‐scans (longitudinal images) and C‐scans (transverse images at constant depth) was used. While the B‐ and C‐scans qualitatively described the lesion detected, the A‐scan which showed the depth (mm) resolved reflectivity (dB) of the tooth tissue was used for the quantitative analysis. After a simple normalization procedure to determine the actual depth the light travelled into the tooth tissue, the area (R) under the A‐scan was quantified as a measure of the degree of reflectivity of the tissue. The result showed that R (dB mm) decreased with increasing demineralization time. The percentage reflectivity loss (R%) in demineralized tissue, which related to the amount of mineral loss, was also calculated, and it was observed that R% increased with increasing demineralization time. It was concluded that with the above procedure, OCT could quantitatively monitor the mineral changes in a caries lesion on a longitudinal basis.
Incisal and condylar paths during habitual mouth opening movement of children with anterior reverse bite in the primary dentition
Authors: Nagata M. , Yamasaki Y. , Hayasaki H. , Nakata M.
Published: March 2003

The purpose of this study was to evaluate whether the path of habitual mouth opening was influenced by anterior reverse bite malocclusion in children. Two groups of children with the primary dentition were chosen: (i) 10 children with anterior reverse bite (reverse bite group) and (ii) 10 with normal occlusion (normal occlusion group). Their habitual mouth opening movements were measured by an opto‐electronic movement‐analysing system with 6 d.f. at a sampling rate of 100 Hz. These movements were projected on the sagittal plane at the incisal and condylar points. To characterize the path, we used the angles between the path and the horizontal plane. In the initial stage of opening, the incisal path of the reverse bite group was displaced more posteriorly from the intercuspal position than that of the normal occlusion group. However, as opening continued, the direction of the path of the reverse bite group was more anterior than those of the normal occlusion group. During the entire opening movement, the condylar path of the reverse bite group was flatter than those of the normal occlusion group. In conclusion, it was demonstrated that anterior reverse bite in the primary dentition clearly affects the paths of habitual opening movements.
Mechanical properties of two restorative reinforced glass–ionomer cements
Authors: Yap A. U. J. , Cheang P. H. N. , Chay P. L.
Published: March 2003

This study investigated the mechanical properties (hardness, compressive and diametral tensile strength) of two restorative reinforced glass–ionomer cements (GC Fuji IX GP and Miracle Mix). The mechanical properties of the two cements were compared after 1 day, 1 week and 1 month storage in distilled water at 37 °C. Hardness testing (VHN) was carried out with a digital microhardness tester (load=50 g, dwell time=30 s) and compressive/diametral tensile strength testing (MPa) was conducted based upon British Standard Specification for Glass–Ionomer Cements (BS 6039: 1981). Results were analysed using analysis of variance (ANOVA)/Scheffe's test and independent samples t‐test (P < 0·05). Mechanical properties generally increased with time for both cements. Hardness at 1 day was significantly lower than that at 1 week and 1 month. No significance difference in compressive and diametral tensile strengths was observed between the different time intervals. After 1 month storage in water, no significant difference in hardness and compressive strength was observed between Fuji IX and Miracle. The diametral tensile strength of Fuji IX was, however, significantly greater than that of Miracle Mix at all time intervals. Fuji IX GP may serve as a potential substitute for Miracle Mix.
Influence of abutment substrate and ceramic thickness on the colour of heat‐pressed ceramic crowns
Authors: NAKAMURA T. , SAITO O. , FUYIKAWA J. , ISHIGAKI S.
Published: March 2003

Summary All‐ceramic crowns made of leucite‐based heat‐pressed ceramics are widely used to restore non‐vital teeth in conjunction with various post and core materials. However, as some light passes through the ceramic, the colour of the abutment substrate can negatively affect the final aesthetic appearance of the all‐ceramic crown. In this study, we made background specimens simulating gold‐alloy cast posts and other simulating porcelain veneered cast posts, overlaid different thickness of heat‐pressed ceramic on these background specimens, and measured the shifts in colour. We found that, when the background specimen was a gold alloy, the background colour had an effect on the apparent colour, unless the ceramic was more than 1·6 mm thick. When the background specimen was porcelain veneered, the background colour had no evident effect, even when the ceramic was not very thick. Therefore, when making a restoration using a leucite‐based heat‐pressed ceramic crown, it is advisable to use tooth‐coloured materials such as a porcelain veneered cast post, if you will not be able to make the ceramic more than 1·6 mm thick.
Periodontal reasons for tooth extraction in an adult population in Jordan
Authors: Quteish Taani D. S. M.
Published: March 2003

summary  This survey studies the reasons for periodontal extraction of permanent teeth in an adult Jordanian population. A random sample of 30 general dental practitioners (GDPs) from a list of 300 GDPs (1:10) was contacted. Of these, the 26 dentists who participated in this study were asked to record teeth extracted and give reasons for extraction. Personal and demographic information and clinical details were obtained from 898 patients aged from 20 to 60 years. A total of 1098 teeth were extracted during the 3‐month study period. The results of this study revealed that dental caries (56·4% overall) was the main reason for tooth extraction, especially in 20–39 year olds. Periodontal disease (23·4% overall) was the next most frequent indication for extraction and became the commonest cause of tooth extraction in patients aged 40 years or more. Other reasons for tooth loss accounted for only 20·2% of the series. Advanced periodontal disease represented by pocketing were the dominant pathology when tooth loss occurred as the result of periodontal disease. As far as the type of tooth was concerned, the most frequently extracted teeth were molars followed by premolars, regardless of whether their loss was the result of the caries or the periodontal disease. This study suggests that caries and its consequences are responsible for more tooth loss in patients less than 40 years of age while extraction because of periodontal problems increases with age, and more commonly related to pocketing.
Validity and reliability of a newly developed method for evaluating masticatory function using discriminant analysis
Authors: Sato S. , Fueki K. , Sato H. , Sueda S. , Shiozaki T. , Kato M. , Ohyama T.
Published: March 2003

summary  The objective of the study was to assess validity and reliability of a newly developed method for evaluating mixing ability of masticatory function. A two‐coloured paraffin wax cube was used as a test food in the mixing ability test. Eleven full dentate and 33 denture wearers participated in the validity assessment. They were divided into three groups according to their dental state. Validity was assessed by the Spearman's coefficient of correlations between the mixing ability test and the sieving method used as a ‘gold standard’ test of the masticatory performance. The subjects were asked to masticate the test foods for 5, 7, 10, 15, 20 and 30 strokes in each test. Significant correlations (P < 0·001) were obtained in natural dentition group (rs=0·66), in denture‐natural dentition group (rs=0·72) and in denture–denture group (rs= 0·56). In the reliability assessment, three full dentate subjects were asked to repeat the mixing ability test a number of times. The intraclass correlation coefficients were 0·94 in interexaminer consistency, 0·98 in intra‐examiner consistency, 0·89 in test–retest consistency and 0·99 in measuring consistency. These results indicated that the mixing ability test had the validity and the reliability for evaluation of the masticatory performance.
From hospital to community: Bridging Therapeutic Relationships
Authors: Forchuk  , Jewell  , Schofield  , Sircelj  , Valledor
Published: March 2003

The ‘Bridge to Discharge’ project evolved from a participatory research project. The team included public health nurses, in‐patient schizophrenia program nurses and mental health consumers. The project focused on therapeutic relationships and used Peplau's theory of Interpersonal Relations. A broad perspective of therapeutic relationships was used that explicitly included both peer and professional support. The theoretical approach is described and illustrated with a case study.
The evolution of an intervention — the use of Peplau's process of practice‐based theory development
Authors: Peden
Published: March 2003

In 1969, at the first Nursing Theory Conference, Hildegard Peplau proposed a research methodology that would guide the development of nursing knowledge. To direct nurses in the development of practice‐based theory, Peplau proposed a three‐step process that would assist in this pursuit. The purpose of this paper is to describe the use of Peplau's process of practice‐based theory development as it has directed a program of research in the area of depression. Peplau's ideas related to practice‐based theory development came at a time in nursing when grand theories were being developed and theoretical nursing was highly valued. Peplau, ahead of her time, proposed an approach that valued the development of nursing knowledge in practice, while also combining both qualitative and quantitative methods. This research methodology deserves recognition today, as one that can guide knowledge development in psychiatric nursing.
The future of the Theory of Interpersonal Relations? A personal reflection on Peplau's legacy
Authors: Barker
Published: March 2003

The work of Hildegard Peplau represents the most significant influence, worldwide, on the development of psychiatric nursing practice. Her use of the Theory of Interpersonal Relations created the basis for defining the potential significance of the psychiatric nurse's role as a therapeutic agent. Forty years later she has indicated the means by which nurses might sharpen their focus on the person often overshadowed by the ‘patient’ label. Peplau's writings have, over this 40‐year period, helped clarify the broad range of roles required of the nurse in general and in particular, within psychotherapeutic nursing.
An evaluation of services for women with long‐term mental health problems
Authors: Owen  , Repper  , Perkins  , Robinson
Published: March 2003

This paper presents the results of an evaluation study of services for women with long‐term mental health problems. The study, which was conducted in a long‐term rehabilitation and community care service, examined the adequacy, accessibility, and responsiveness of services provided for women users; explored differences between the men and women using the service and those newly admitted to it; and explored the views and experiences of service providers and the women users themselves. The results of the study confirm and extend those of previous studies and suggest a number of service recommendations. The unevenness in attention to the needs of women across services needs to be addressed. Services should be more attractive to women. Agencies and facilities for women outside mental health services should be supported to ensure the they can accommodate women with long‐term mental health problems, and the women themselves need to be offered the support necessary to ensure they have access to such facilities. Finally, efforts must be made to ensure that services both recognize the losses that women with long‐term mental health problems have experienced and foster their continued hopes and aspirations for the future.
The process of constant observation: perspectives of staff and suicidal patients
Authors: Fletcher
Published: March 2003

This ethnographic study explores the perceptions of staff regarding the nursing activity of constant observation of the suicidal patient in mental health settings. Unusually, the paper also addresses the perceptions of the patients themselves, and compares the two. Two major categories of nursing interventions, Therapeutic and Controlling, were identified by both groups of respondents. However, although there was a degree of commonality between the groups’ descriptions of subcategories, there are also interesting anomalies. Patients did not perceive some actions at all, one action was not perceived by staff, and one action was perceived to be in different categories by the two groups. Such differences are discussed, and implications explored.
Triumvirate nursing for personality disordered patients: crossing the boundaries safely
Authors: Melia  , Moran  , Mason
Published: March 2003

As the issue of the treatment and effective management of personality disordered patients comes under close scrutiny in the wake of the Fallon Inquiry, we offer a brief overview of the nature of the challenges involved in nursing this difficult group of patients. Traditional methods of setting limits and defining boundaries are no longer convincing amidst the allegations of multidisciplinary staff being culpable, at one level or another, for their contribution in this tragic inquiry. In this paper we offer a strategic mechanism of constructing nursing care for this difficult group of patients and provide a framework for crossing boundaries safely through a multidisciplinary framework. We term this triumvirate nursing.

Nursing management of those patients considered to have personality disorders is traditionally very difficult. This difficulty, in part, stems from the inability of nurses to strategically develop therapeutic relationships in a safe manner. Crossing boundaries is a necessary part of therapeutic exploration and relationship building; triumvirate nursing offers a safe mechanism for undertaking this. Creative thinking is a necessary part of the future development of the nursing management of these disorders.
Stress and burnout in forensic community mental health nurses: an investigation of its causes and effects
Authors: Coffey M.
Published: March 2003

The increasing development of forensic services has seen the numbers of Forensic Community Mental Health Nurses (FCMHNs) mushroom. Community mental health nursing (CMHNs) has been found to be a stressful occupation. FCMHNs have largely been ignored in research into occupational stress. The current study identified and surveyed all FCMHNs (n = 104) in England and Wales who were attached to NHS Medium Secure Units using measures of occupational stress. A response rate of 76.9% was achieved. Findings from this study showed that a substantial portion (44.3%) of FCMHNs were experiencing high burnout in relation to emotional exhaustion. A number (31.2%) of FCMHNs reached or exceeded the threshold for psychiatric caseness on one measure. Concerns of FCMHNs included ‘not having facilities in the community to refer patients on to’ and ‘interruptions in the office’. Dealing with violent patients did not feature in the top 10 stressors, although dealing with suicidal patients did. As a group FCMHNs appear to feel supported by their managers and colleagues.
Psychopharmacological and electroconvulsive treatment of anxiety and depression in the elderly
Authors: Heffern W. A.
Published: March 2003

The pharmacotherapeutics of antianxiety and antidepressant medication in the elderly is reviewed, and the benefits and risks of electroconvulsive therapy (ECT) are discussed. Physiological changes in normal ageing are described, and the pharmacodynamic and pharmacokinetic implications are addressed. Finally, the role of the advanced practice nurse (mental health/psychiatry) is discussed in terms of accountability, collaboration, and the development of empirical knowledge to enhance quality patient care.
Service users and mental health nursing
Authors: Edwards K.
Published: March 2003

A better understanding of the views of service users has become increasingly relevant in providing mental health services and for the role of the mental health nurse in meeting users' needs. The four key issues that this research endeavoured to address were: (1) What are the views and perceived needs of users of mental health services in the context of the role that users see nurses fulfilling? (2) How do student nurses perceive their future role given the changes in nurse preparation? (3) To what extent do the answers to the first two questions converge and/or diverge? (4) Recommend actions on ways in which mental health nurse training could be improved, in light of the findings of this research. Methodologically, both qualitative and quantitative data gathering approaches were used, the former for stage one in setting the agenda and the latter for stage two by means of questionnaires. The findings indicate that the key concerns for users are issues of choice, individuality, information and quality of care in terms of positive interpersonal relationships with those who have responsibilities for helping them and who are sensitive to their real needs. Users are not asking for any costly or extravagant therapies but support that is relevant to their needs and provided in a compassionate manner. The context of their lives and the degree to which users feel integrated into society is a prominent concern. These findings have implications for how mental health nurses are educated and trained and how on qualifying they function in practice. The findings throw into question whether mental health nursing can adapt to the desired changes that are being called for.
A qualitative study exploring how qualified mental health nurses deal with incidents that conflict with their accountability
Authors: Mitchell G. J.
Published: March 2003

In reviewing the literature on accountability within nursing practice, it became clear that accountability is a complex issue. By using a qualitative new paradigm approach, this study explored how 22 mental health nurses deal with the complex issue of conflict in their accountability within their daily practice, by taking a ‘snapshot’ of their practice. This was achieved by using written critical incidents as proposed by Flanagan (1954), as this allows the researcher to explore the real clinical situations, as identified by the nurse. Cormack’s (1983, 1996) technique for analyses of critical incidents was used. The results identified that these nurses are working in an environment in which they have to deal with aggression, suicide and a lack of support from their line managers, as well as from medical colleagues. The nurses in this study identified the importance of team support; clinical supervision and debriefing as methods which help them deal with issues that affect their accountability, within their practice.
The Tidal Model: developing an empowering, person‐centred approach to recovery within psychiatric and mental health nursing
Authors: Barker P.
Published: March 2003

Nursing theories and nursing models have a low profile within psychiatric and mental health nursing in the United Kingdom. This paper describes the philosophical and theoretical background of the Tidal Model, which emerged from a 5‐year study of the ‘need for psychiatric nursing’. The Tidal Model extends and develops some of the traditional assumptions concerning the centrality of interpersonal relations within nursing practice. The model also integrates discrete processes for re‐empowering the person who is disempowered by mental distress or psychiatric services or both. The paper reports briefly on the ongoing evaluation of the model in practice.
Mass media, ‘monsters’ and mental health clients: the need for increased lobbying
Authors: Cutcliffe J. R. , Hannigan B.
Published: March 2003

A review of the limited empirical and theoretical literature indicates that current mass media representations of mental health service users appear to emphasize violence, dangerousness and criminality. This is despite the empirical evidence that indicates a decline over the last 40 years in the number of homicides carried out by people identified as suffering from mental health problems. Such inappropriate representations do much to increase stigma, ostracism, harassment and victimization of these individuals by the public. Furthermore, it can be argued that there is another repercussion of these representations and that is the subsequent government position/policy and the resulting legislation concerning care of people with mental health problems. Consequently, this paper argues that there is a clear need for psychiatric/mental health (P/MH) nurses to become more mindful of the wider, socio‐political environment in which their practice occurs, particularly if psycho‐social approaches to practice are adopted in their fullest sense, and as a result increase their political lobby. Such increased lobbying should occur on behalf of, and in collaboration with, service users, and accordingly the authors describe a range of activities under the broad headings of pro‐active and reactive lobbying. Furthermore, it is incumbent upon P/MH nurse educationalists to prepare aspirant P/MH nurses for this lobbying role and equip them with the skills necessary to do so.
Exploring the relationship between work stress, years of experience and emotional competency using a sample of Australian mental health nurses
Authors: Humpel N. , Caputi P.
Published: March 2003

This paper reports an exploratory study examining the relationship between emotional competency and work stress, and the association between the length of time in mental health nursing and emotional competency and stress. A significant relationship was found between emotional competency and years of experience. Nurses with six years and more experience had higher levels of emotional competency. This relationship was stronger for female than male nurses. Nurses with less than two years in the nursing profession were found to experience significantly more personal self‐doubt than nurses with greater nursing experience.
Consent and long‐term neuroleptic treatment
Authors: Harris N. R. , Lovell K. , Day J. C.
Published: March 2003

The involvement of clients in the process of developing their care and treatment package is well established. If a genuine collaboration in treatment is achieved one of the fundamental bases of this process lies with ‘informed consent’. Neuroleptic medication forms the basis of relapse prevention treatment for people suffering from schizophrenia with non‐adherence to treatment seen as the largest cause of relapse. This paper reviews the complex and difficult issues in obtaining informed consent for this client group from within the context of the nurse's role and the problems that arise as a consequence of the blurring of professional boundaries. Throughout the paper reference is made to the expectations made by the UKCC, which provides clarification of nurses’ practice in this area.
Deaths associated with restraint use in health and social care in the UK. The results of a preliminary survey
Authors: PATERSON B. , BRADLEY P. , STARK C. , SADDLER D. , LEADBETTER D. , ALLEN D.
Published: March 2003

Many aspects of the management of acutely disturbed behaviour have only relatively recently come under systematic scrutiny. Perhaps regrettably one of the last amongst the range of strategies that may be employed to be subjected to rigorous examination has been physical restraint. Considerable debate has recently taken place around what represents good practice in this sensitive and controversial area but the continuing dearth of research in some aspects of this area of practice has meant that this discussion has arguably been over reliant on ‘expert’ opinion. Questions continue regarding some fundamental issues of restraint, including the relative risks involved in alternative approaches, and anxieties have been expressed about the potential for injuries and death to result from restraint. This article outlines the results of a survey that sought to explore the incidence of deaths associated with restraint in health and social care settings in the UK. The outcome of an initial analysis of the cases identified is then discussed, with reference to the literature on restraint‐related deaths, in order to identify the implications for practice.
The clients’ experience of the community group: implications for nurse facilitators
Authors: HARMS S. , BENSON A.
Published: March 2003

Community or large group meetings occur in many mental health units. Literature is available that describes the possible functions of such groups, but little is known about how they are actually experienced by the members, or the implications of this for nurse facilitators, especially in the current context of inpatient care. The aim of this study was to develop an understanding of the clients’ experience of the daily community group in a unit that offered both an inpatient and a day patient service for adults experiencing mental health problems. The group meeting was intended to provide an opportunity for people to examine their relationships with others and discover new ways of coping with problems and stressors. The group had a changing membership, with all staff and clients present on the unit at the time expected to attend. The meeting lasted for an hour and had no predetermined agenda. Mental health nurses made up the majority of the staff membership. Semistructured interviews were conducted with four clients who had been attending the group for between 3 and 6 months. These were tape recorded, transcribed verbatim and then analysed using the phenomenological approach of Colaizzi. Three themes emerged from the data: ‘Whose Responsibility?’, ‘Me vs. Them’ and ‘What Works?’ These themes have implications for nurse facilitators, namely: their awareness that such issues are of importance; their ability to recognize how and when they are present; and their ability to effectively intervene.
Autonomic markers of arousal during sleep in patients undergoing investigation for obstructive sleep apnoea, their relationship to EEG arousals, respiratory events and subjective sleepiness
Authors: PITSON D. , STRADLING J.
Published: March 2003

Estimating the degree of sleep fragmentation is an important part of a respiratory sleep study and is conventionally measured using EEG micro arousals or is inferred indirectly from respiratory abnormalities such as apnoeas and desaturations. There is a need for less labour‐intensive measures of sleep fragmentation, and transient rises in blood pressure and heart rate may fulfil this role. Forty unselected sleep clinic referrals undergoing investigation for possible obstructive sleep apnoea (OSA) were studied with one night of polysomnography. Three conventional indices of sleep fragmentation (EEG micro arousals, apnoea/hypopnoea index (AHI) and oxygen saturation dip rate (SaO2 dips)) and two autonomic indices (heart rate and blood pressure rises) have been compared. Correlations between these five indices ranged from r=0.38 to r=0.73. Of the two autonomic indices, the correlations for blood pressure rises with SaO2 dips and EEG micro arousals were stronger (r=0.71 and r=0.65, respectively) than those for heart rate rises (0.55 and 0.51). All indices of sleep fragmentation, apart from heart rate rises, were similar in their correlation with subjective sleepiness (r‐values 0.21–0.36). Arousals implied from blood pressure rises (using pulse transit time) can be measured easily, are objective, and appear no worse at predicting subjective sleepiness than either EEG micro arousals or AHI. They may therefore provide a useful alternative to manual scoring of micro arousals from the EEG as an index of sleep fragmentation in sleep clinic patients undergoing investigation for possible OSA.
Humoral regulation of physiological sleep: cytokines and GHRH
Authors: Krueger  , Obál, Jr  , Fang
Published: March 2003

Interleukin‐1, tumour necrosis factor, and growth hormone releasing hormone form part of the humoral mechanisms regulating physiological sleep. Their injection enhances non‐rapid‐eye‐movement sleep whereas their inhibition reduces spontaneous sleep and sleep rebound after sleep deprivation. Changes in their mRNA levels and changes in their protein levels in the brain are consistent within their proposed role in sleep regulation. Furthermore, results from transgenic and mutant animals also are suggestive of their role in sleep regulation. The sites responsible for the growth hormone releasing hormone somnogenic activity seem to reside in the anterior hypothalamus/basal forebrain. Somnogenic sites for interleukin‐1 and tumour necrosis factor likely include the anterior hypothalamus, but also may extend beyond that area. These substances elicit non‐rapid‐eye‐movement sleep via a biochemical cascade that includes other known sleep regulatory substances.
Sleep‐disordered breathing in a predominantly African‐American pediatric population
Authors: STEPANSKI E. , ZAYYAD A. , NIGRO C. , LOPATA M. , BASNER R.
Published: March 2003

The goal of this study was to characterize sleep and respiratory parameters in children with sleep‐disordered breathing (SDB) as compared to children without SDB. Data are from 198 children and adolescents referred for sleep center evaluation, 128 of whom were diagnosed with SDB. In children with SDB, obesity (> 95% wgt for age) was more common than being severely underweight (< 5% wgt for age), but only the older children with SDB were heavier than age‐matched normal sleepers. Children with SDB had increased EEG arousals; sleep architecture was not otherwise significantly different from the non‐SDB group. African‐American children with SDB had significantly greater oxygen desaturation with obstructive events compared to Caucasian and Latino children. It appears that the role of obesity as a risk factor for obstructive sleep apnea (OSA) increases in children above the age of 8‐years. Additionally, African‐American children with SDB may be at increased risk for hypoxemia and cardiovascular consequences of SDB.
Inducing jet‐lag in older people: Directional asymmetry
Authors: Monk Timothy H. , Buysse Daniel J. , Carrier Julie , Kupfer David J.
Published: March 2003

Twenty healthy elderly subjects (12 female, 8 male; mean age 81 years, range 67–87 years) each experienced a 15‐day time isolation protocol in which they lived individually in a special laboratory apartment in which sleep and circadian rhythm measures could be taken. There were two experiments: one (6 females, 4 males) involved a 6‐h phase advance of the sleep/wake cycle, and the other (6 females, 4 males) a 6‐h phase delay. Each started with 5 baseline days, immediately followed by the phase shift. The subject was then held to the phase shifted routine for the remainder of the study. Rectal temperatures were recorded minute‐by‐minute throughout the entire experiment and each night of sleep was recorded using polysomnography. A directional asymmetry in phase‐shift effects was apparent, with significantly more sleep disruption and circadian rhythm amplitude disruption after the phase advance than after the phase delay. Sleep disruption was reflected in reduced time spent asleep, and in changed REM latency, which increased in the phase advance direction but decreased in the phase delay direction. Although the phase advance led to a significant increase in wakefulness in the first half of the night, the phase delay did not lead to an equivalent increase in wakefulness during the second half of the night. Examination of both raw and ‘demasked’ circadian rectal temperature rhythms confirmed that phase adjustment was slow in both directions, but was less slow (and more monotonic) after the phase delay than after the phase advance. Subjective alertness suffered more disruption after the phase advance than after the phase delay.
Age differences in the spontaneous termination of sleep
Authors: Murphy Patricia J. , Rogers Naomi L. , Campbell Scott S.
Published: March 2003

The stage from which the spontaneous ending of sleep occurred was investigated in 138 sleep episodes obtained from 14 younger (19–28 years) and 11 older (60–82 years) individuals. The possible influences of circadian phase and quality of the preceding sleep period, as well as the impact of aging on characteristics of sleep termination were examined. Under experimental conditions in which subjects were isolated from time cues, and behavioral options to sleep were limited, no age‐associated differences in the duration of sleep periods, or in the number or duration of REM episodes were observed. Despite similar percentages of NREM (stages 2–4) and REM sleep across age groups, younger subjects awakened preferentially from REM while older subjects did not. Of the sleep episodes obtained from older subjects, those with sleep efficiencies higher than the median were more likely to terminate from REM than those with lower sleep efficiencies. For all subjects, the REM episodes from which sleep termination occurred were truncated relative to those that did not end the sleep period. In addition, nonterminating REM episodes that were interrupted by a stage shift were most often interrupted by brief arousals to stage 0. Such arousals within nonterminating REM episodes occurred, on average, after a similar duration as the terminating point of sleep‐ending REM episodes. The results from this study demonstrate that there are age‐related differences in the sleep stage from which spontaneous awakenings occur, and that these differences may be due in part to the quality of the sleep period preceding termination. Findings regarding the characteristics of both terminating and nonterminating REM episodes are consistent with the notion that the neural and biochemical context of REM sleep may facilitate a smooth transition to wakefulness. It is speculated that age‐associated changes in sleep continuity may render unnecessary the putative role of REM sleep in providing a ‘gate’ to wakefulness.
The effect of arousals during sleep onset on estimates of sleep onset latency
Authors: Smith Simon , Trinder John
Published: March 2003

It is well established that insomniacs overestimate sleep‐onset latency. Furthermore, there is evidence that brief arousals from sleep may occur more frequently in insomnia. This study examined the hypothesis that brief arousals from sleep influence the perception of sleep‐onset latency. An average of four sleep onsets was obtained from each of 20 normal subjects on each of two nonconsecutive, counterbalanced, experimental nights. The experimental nights consisted of a control night (control condition) and a condition in which a moderate respiratory load was applied to increase the frequency of microarousals during sleep onset (mask condition). Subjective estimation of sleep‐onset latency and indices of sleep quality were assessed by self‐report inventory. Objective measures of sleep‐onset latency and microarousals were assessed using polysomnography. Results showed that sleep‐onset latency estimates were longer in the mask condition than in the control condition, an effect not reflected in objective sleep‐stage scoring of sleep‐onset latency. Furthermore, an increase in the frequency of brief arousals from sleep was detected in the mask condition, and this is a possible source for the sleep‐onset latency increase perceived by the subjects. Findings are consistent with the concept of a physiological basis for sleep misperception in insomnia.
Simulated driving performance following prolonged wakefulness and alcohol consumption: separate and combined contributions to impairment
Authors: Arnedt  , Wilde  , Munt  , Maclean
Published: March 2003

The separate and combined effects of prolonged wakefulness and alcohol were compared on measures of subjective sleepiness, simulated driving performance and drivers’ ability to judge impairment. Twenty‐two males aged between 19 and 35 years were tested on four occasions. Subjects drove for 30 min on a simulated driving task under conditions determined by the factorial combination of 16 and 20 h of wakefulness and blood alcohol concentrations of 0.00 and 0.08%. The simulated driving session took place 30 min postingestion; subjects in the two alcohol conditions participated in a second 30‐min driving session 90‐min postingestion. Subjects made simultaneous ratings of their impairment while driving and retrospective ratings at the end of each test session. Subjective sleepiness measures were completed before and after each driving session. The combination of 20 h of prolonged wakefulness and alcohol produced significantly lower ratings of subjective sleepiness and driving performance that was worse, but not significantly so, than would be expected from the additive effects of each condition alone. Driving performance was always worse in the second driving session, during the elimination phase of alcohol metabolism, despite blood alcohol concentrations being lower than during the first driving session. There was a modest association between perceived and actual impairments in driving performance following prolonged wakefulness and alcohol. The findings suggest that the combination of prolonged wakefulness and alcohol consumption produced greater decrements in simulated driving performance than each condition alone and that drivers have only a modest ability to appreciate the magnitude of their impairment.
Health‐related quality of life in narcolepsy
Authors: Daniels Emma , King Martin A. , Smith Ian E. , Shneerson John M.
Published: March 2003

Narcolepsy is a chronic sleep disorder characterised by symptoms of excessive daytime sleepiness and cataplexy. The aim of this study was to describe the health‐related quality of life of people with narcolepsy residing in the UK. The study comprised a postal survey of 500 members of the UK narcolepsy patient association, which included amongst other questions the UK Short Form 36 (SF‐36), the Beck Depression Inventory (BDI), and the Ullanlinna Narcolepsy Scale (UNS). A total of 305 questionnaires were included in the final analysis. The results showed that the subjects had significantly lower median scores on all eight domains of the SF‐36 than normative data, and scored particularly poorly for the domains of role physical, energy/vitality, and social functioning. The BDI indicated that 56.9% of subjects had some degree of depression. In addition, many individuals described limitations on their education, home, work and social life caused by their symptoms. There was little difference between the groups receiving different types of medication. This study is the largest of its type in the UK, although the limitations of using a sample from a patient association have been recognised. The results are consistent with studies of narcolepsy in other countries in demonstrating the extensive impact of this disorder on health‐related quality of life.
Increased cerebral response during a divided attention task following sleep deprivation
Authors: Drummond Sean P. A. , Gillin J. Christian , Brown Gregory G.
Published: March 2003

We recently reported that the brain showed greater responsiveness to some cognitive demands following total sleep deprivation (TSD). Specifically, verbal learning led to increased cerebral activation following TSD while arithmetic resulted in decreased activation. Here we report data from a divided attention task that combined verbal learning and arithmetic. Thirteen normal control subjects performed the task while undergoing functional magnetic resonance imaging (FMRI) scans after a normal night of sleep and following 35 h TSD. Behaviourally, subjects showed only modest impairments following TSD. With respect to cerebral activation, the results showed (a) increased activation in the prefrontal cortex and parietal lobes, particularly in the right hemisphere, following TSD, (b) activation in left inferior frontal gyrus correlated with increased subjective sleepiness after TSD, and (c) activation in bilateral parietal lobes correlated with the extent of intact memory performance after TSD. Many of the brain regions showing a greater response after TSD compared with normal sleep are thought to be involved in control of attention. These data imply that the divided attention task required more attentional resources (specifically, performance monitoring and sustained attention) following TSD than after normal sleep. Other neuroimaging results may relate to the verbal learning and/or arithmetic demands of the task. This is the first study to examine divided attention performance after TSD with neuroimaging and supports our previous suggestion that the brain may be more plastic during cognitive performance following TSD than previously thought.
Long‐term vs. short‐term processes regulating REM sleep
Authors: FRANKEN PAUL
Published: March 2003

In cats, rats, and mice, the amount of rapid eye movement sleep (REMS) lost during a sleep deprivation (SD) predicts the subsequent REMS rebound during recovery sleep. This suggests that REMS is homeostatically regulated and that a need or pressure for REMS accumulates in its absence, i.e. during both wakefulness and non‐rapid eye movement sleep (NREMS). Conversely, it has been proposed that REMS pressure accumulates exclusively during NREMS [Benington and Heller, Am. J. Physiol. 266 (1994) R1992; Prog. Neurobiol. 44 (1994b) 433]. This hypothesis is based on the analysis of the duration of successive NREMS and REMS episodes and of electroencephalogram (EEG) events preceding REMS. Pre‐REMS events (PREs) do not always result in sustained REMS and can thus be regarded as REMS attempts that increase as NREMS progresses. It is assumed that two processes regulating REMS can resolve the apparent contradiction between these two concepts: a `long‐term' process that homeostatically regulates the daily REMS amount and a `short‐term' process that regulates the NREM–REMS cycle. These issues were addressed in two SD experiments in rats. The two SDs varied in length (12 and 24 h) and resulted in very similar compensatory changes in NREMS but evoked very different changes for all REMS parameters studied. The large REMS increase observed after 24‐h SD was accompanied by a reduction in unsuccessful PREs and an increase in sustained REMS episodes, together resulting in a threefold increase in the success‐rate to enter REMS. Changes in success‐rate matched those of a theoretically derived long‐term REMS pressure. The SD induced changes in sleep architecture could be reproduced by assuming that the increased long‐term REMS pressure interacts with the short‐term process by increasing the probability to enter and remain in REMS.