bluuebunny/crossref_metadata_2025 huggingface dataset:
Length of the occlusal glide at the lower incisal point during chewing
Authors: Hayasaki H. , Sawami T. , Saitoh I. , Nakata S. , Yamasaki Y. , Nakata M.
Published: March 2003

SUMMARY  The purpose of this study was to estimate the length of the occlusal glide during gum chewing at the lower incisal point. Mandibular excursions with occlusal contacts in 25 females with permanent dentition were recorded using an optoelectronic system that can measure mandibular movement with 6 d.f. at a sampling frequency of 100 Hz. A curved mesh diagram of incisor coordinates during maximum mandibular excursions (CMDME) was plotted. Gum chewing movement was also measured using the same system and computer software which divided the chewing movement into cycles at each maximum opening position. Each cycle was standardized at 0·1 mm intervals from the most closed position. Finally, the distance between the CMDME and each position of the incisor during a chewing cycle was calculated. Whenever, this distance was less than 0·2 mm opposing teeth were considered to be in contact. The occlusal glide was defined as the distance travelled by the lower incisal point as the mandible moved along occlusal contacts of the CMDME. The vertical coordinates at the beginning of the occlusal glide (during closing) and at the end of occlusal glide (during opening) were also calculated. The lengths of the occlusal glide pathway averaged 1·29 mm during closing and 1·55 mm during opening, a total length of 2·84 mm. Mean vertical coordinates at the beginning and end of the glide were −0·95 and −1.12 mm from intercuspal position, respectively.
Multidisciplinary examination of patients with illness attributed to dental fillings
Authors: Langworth S. , Björkman L. , Elinder C.‐G. , Järup L. , Savlin P.
Published: March 2003

Summary Objective and methods. In 1993, a special Amalgam Clinic was established at Huddinge University Hospital. Residents in the Stockholm County area with morbidity attributed to dental fillings (‘amalgam disease’), were referred to this clinic. Patients were examined by a dentist (n  428), a physician (n  379), and a psychologist (n  360). Sixty‐nine per cent were women and 31% men; the mean patient age was 46 years. Results. Oral symptoms included tender or aching teeth (60%), metallic taste (54%), sore mouth (43%) and dry mouth (43%). Signs of moderate or severe temporomandibular joint dysfunction were found in 81 cases, glossitis in 30 and oral lichen in 26 cases. Common general symptoms included diffuse pain (78%), general weakness (75%), extreme fatigue (68%) and dizziness (68%). Seven per cent of the patients suffered from previously undiagnosed medical conditions (thyroid dysfunction, anaemia, cardiopathy, renal disease, cancer). In 26 subjects, skin patch testing revealed allergy to mercury, gold or palladium. The median concentration of mercury was 10 nmol L−1 in whole blood, 3 nmol L−1 in plasma and 10 nmol L−1 in urine, i.e. normal levels. Earlier mental trauma was common, and in the psychological questionnaire SCL‐90, clear tendencies to somatization were found. Only a few cases of severe psychiatric illness were observed. No positive correlation was found between the amount of amalgam and somatic symptoms or psychological effect parameters. Conclusions. The results do not support the hypothesis that release of mercury from amalgam fillings is the cause of ‘amalgam disease’, but suggest that there may be various explanations for the patient's complaints.
Incidence of temporomandibular disorders (TMDs) in senior dental students in Taiwan
Authors: Chuang S.‐Y.
Published: March 2003

summary Two‐hundred and fifty‐four (159 male, 95 female) senior dental students (mean age: 22·34 ± 1·2 years) were asked to answer 14 questions. Scoring instructions accompanying this questionnaire indicated that the number of ‘yes’ responses was directly related to the probability of temporomandibular disorders (TMD). This survey of students was used to determine the prevalence of TMD. In addition, item analysis was performed to determine if there were any differences between male and female responses. The results of the study were as follows. The most prominent symptom suggesting TMD was the presence of clicking sound(s), both in females and males. The second most prominent symptom in female students was an awareness of stress, whereas teeth sensitivity was second in male students. Female students 18·95% and male students 29·56% did not answer ‘yes’ to these questions, and significantly (P < 0·05) higher in males than in females. The frequency of more than four ‘yes’ answers was 15·79% in the female group and 5·66% in the male group, and significantly (P < 0·001) lower in males than in females. The type of symptoms and the frequency of TMDs were higher in female students than in male students and jaw click was the most common finding both in male and female dental students. The difference in reported problems between male and female students centred on a dentition factor in males and a psychological factor in female students.
Influence of muscle contraction and jaw movement speed on the estimation of chewing force from elevator muscle EMG
Authors: PRÖSCHEL P. , RINNE H. , MORNEBURG T.
Published: March 2003

Recent studies have shown that an additional muscle activity (AMA) in chewing was responsible for excessive masticatory forces that had been estimated from isometric bite force–activity relations. Our aim was to test the thesis that this AMA could be identical to the speed‐dependent ‘anticipatory activity’ that was found in symmetrical jaw closing (Abbink et al., 1999). In this case, forces estimated from EMG should be realistic for slow mastication, but should strongly increase with faster chewing movements.

In 56 dentate volunteers the activities of bilateral masseter and anterior temporal muscles were measured during (a) right‐sided chewing, (b) right‐sided isometric clenching on a bite fork with alternating loads. These biting tasks were carried out with slow, habitual and fast contraction/movement speeds (30, 64, 102 cycles min−1). Masticatory forces were estimated for each speed by putting activities found in task (a) into bite force/activity relations obtained from task (b).

In slow and habitual mastication, activities of the working side masseter were equal and exceeded the corresponding clenching activities by factors of 2·8 and 2·4, respectively (P < 0·001). Consequently, forces estimated from slow (680 N) and habitual (695 N) chewing did not differ significantly and were unrealistically high. These estimated forces and hence the corresponding AMAs did not depend on the speed movement in the same way as the anticipatory activity described inAbbink et al. (1999). In contrast, forces estimated from fast chewing (811 N) were significantly higher (P < 0·001) and corresponding AMAs qualitatively behaved like anticipatory activities. In conclusion, the AMA in chewing could be explained by anticipatory muscle activity for high movement speeds. In slow and habitual chewing however, the AMA may contain amounts of activity with a different origin.
Palatal plate of different designs for the suppression of masseter muscle activity during sleep. A challenge to the concept of placebo splint
Authors: MINAGI S. , OKAMOTO M. , SHIMAMURA M. , SATO T.
Published: March 2003

Several designs of palatal appliance have been reported for the treatment of craniomandibular disorders. However, the effect of these appliances has not yet been fully clarified. This study aimed to reveal the effect of palatal appliances of different design on masseter muscle activity during sleep.

Four volunteers (three women and one man, mean age 36·0 years) were used in this study. For each subject, four different types of palatal appliances were used. The palatal appliances were (1) horse shoe type (1 mm thick), (2) thin appliance which covered the whole palate (1 mm thick), (3) thick appliance which filled the palatal concavity and (4) appliance with half the thickness of the third appliance.

These appliances were worn for 1 week in a randomized sequence with 1‐week interval between each appliance. Right masseter muscle EMG was recorded three nights per week at home. The EMG signal longer than 0·25 s was classified as a burst and a signal shorter than 0·25 s was classified as a brief burst of fragmentary myoclonus (FM).

Mean number of burst per hour for four subjects were 7·99 ± 7·32, 3·52 ± 1·95, 5·90 ± 3·99, 2·87 ± 2·87 and 9·96 ± 6·02 for base line, appliance 1, 2, 3 and 4, respectively. Mean number of FM per hour were 136·86 ± 69·88, 90·53 ± 41·19, 99·49 ± 39·29, 71·66 ± 24·66 and 144·39 ± 42·97, respectively.

From these results, it was suggested that the thick palatal appliance suppressed the masseter muscle activity during sleep most effectively. Also, the results for appliance 4 questioned the concept of placebo effect for non‐occlusal appliances.
Finite element analysis of the possible mechanism of cervical lesion formation by occlusal force
Authors: Tanaka M. , Naito T. , Yokota M. , Kohno M.
Published: March 2003

summary  Recently, various authors have proposed the interesting idea that occlusal force may be a principal factor in cervical lesions of the tooth. It is speculated that the lateral force in non‐ideal mastication causes the tooth to bend and that the resulting tensile stress damages the enamel surface. In this study, we carried out stress analysis on the upper central incisor and the lower first molar using the plastic–elastic deformation theory with two‐dimensional finite element method (FEM). The essential feature that the tensile yield strength is much smaller than the compressive one was taken into account. Our results suggested that oblique loading on the tooth stretches the enamel surface near the cemento‐enamel junction and causes plastic deformation which eventually leads to the cervical lesion.
A comparison of the in vitro cytotoxicity of two root canal sealers
Authors: Öztan M. Dartar , Yilmaz Ş. , Kalayci A. , Zai̇moğlu L.
Published: March 2003

summary  The purpose of this study was to compare the cytotoxicity of an epoxy resin‐based sealer (AH Plus) and a silicone‐based sealer (Roeko Seal Automix, RSA). Cytotoxicity was assessed using the MTT assay for mitochondrial enzyme activity and haemocytometer viable cell counting after 24, 48 and 72‐h exposure to L929 cells. AH Plus and RSA showed no statistically significant difference in the degree of toxicity. Both sealers had a low toxic influence on the cells during the experimental period. This study indicates that epoxy resin‐based sealer AH Plus and the silicone‐based sealer RSA have similar levels of cytotoxicity to mouse fibroblasts.
Mechanical properties of calcium phosphate based dental filling and regeneration materials
Authors: Lee Y.‐K. , Lim B.‐S. , Kim C.‐W.
Published: March 2003

summary  The objective of this study was to compare the mechanical properties of calcium phosphate cements (CPC) for possible dental applications with varied liquid and powder compositions under the same testing condition. Cements studied in this experiment were divided into two groups of CPC not containing polymer and polymeric CPC (PCPC). Cement powder was formed by combining equimolar amounts of dicalcium phosphate anhydrous and tetracalcium phosphate, or acrylic resin polymer powder mixture. The CPC specimens for the compressive strength (CS) and diametral tensile strength (DTS) measurements were prepared by mixing powder and liquid for 30 s with a powder/liquid ratio of 3:1, and subsequently packing the paste into a brass mould. The specimens were kept at 37 °C and 100% relative humidity for 24 h before measurements were conducted on a Universal Testing Machine with a cross‐head speed of 1 mm min–1. The CS of CPC was 0ḃ14–10ḃ29 MPa and that of PCPC was 0ḃ26–117ḃ58 MPa. The DTS of CPC was 0ḃ10–4ḃ56 MPa and that of PCPC was 0ḃ07–22ḃ54 MPa. The CS and DTS were very diverse depending on the composition of powder and liquid. Some compositions showed higher values than commercial liners. Thus compositions of 2% carboxymethyl cellulose + 35% citric acid in phosphate buffered saline (PBS), 20% gelatin in PBS, 2% sodium alginate in PBS, 20–40% aqueous acrylic‐maleic copolymer solution, and some of the HPMC and PMVE‐Ma solutions exhibited promising formulae for dentine regenerating materials. Acrylic resin‐PCPC group showed generally higher CS and DTS values. Based on this study, further studies on the reaction with odontoblast and resultant dentine regeneration should be performed using promising compositions.
Paradigms for mental health nursing: fragmentation or integration?
Authors: Chan  , Rudman
Published: March 2003

Debate about the best paradigm for mental health nursing is compounded by threats from mainstreaming and genericism. In nursing education, integrated practice may have been devalued in a matrix of reductionist disciplines. The ‘gendered’ nature of professional knowledge may create a schismatic and self‐defeating attitude in nurses. Conversely, nurses may be exhorted to adopt a ‘male’ paradigm in order to gain academic credibility, in which the caring dimension may be lost. Other polarities such as ideological distinctions between treatment in hospital and care in the community lead to conceptual confusion. These schisms in care are detrimental to both professionals and users. The writers argue that these tensions may be addressed in an ‘androgenous’ model which presents a challenge to both value systems, rejects the dominance of schismatic models, and offers the potential for a new professional integrity.
Explorations in body image care: Peplau and practice knowledge
Authors: Price
Published: March 2003

Practitioners in mental health care have long utilized the work of Hildegard Peplau, both for nursing discourse and for practice. At a time when the role of theory in practice is once more being debated, and when theories are being applied in new contexts, this paper examines the contribution that Peplau's work may have to offer altered body image nursing care. A case study is used to highlight concepts in practice, the paper examining the ways in which Peplau's Theory of Interpersonal Relations complement the other elements of practice knowledge that the nurse uses to assist patients and lay carers alike.
The concept of serious mental illness: modern myths and grim realities
Authors: Barker  , Keady  , Croom  , Stevenson  , Adams  , Reynolds
Published: March 2003

Current mental health practice and legislation is influenced significantly by the ill‐defined concept of serious mental illness (SMI). Although the concept of SMI originally appeared to include a consideration of a range of forms of mental illness, including dementias, by custom and practice the term has come to mean, often, only people with a psychotic diagnosis. This paper reviews the influence of the term SMI, considering the way older people, younger people and other subgroups within the ‘adult’ population have been marginalized by the narrow definition of the concept. The paper concludes with a consideration of some of the ethical implications of mental health nurses focusing on an ill‐defined ‘illness’ grouping, and the impact that such a narrow focus might have on the ambition to establish ‘health for all by the year 2000’.
The effects of multisensory environments on older people with dementia
Authors: HOPE
Published: March 2003

This paper reports on the findings of an initial evaluation of the effects of exposing older people with dementia to a multisensory environment. Data collected about 29 patients demonstrated that this was generally a positive experience in terms of response to equipment and effect on behaviour. This was not the case for all patients, tactile equipment generating the most negative responses when it occurred. Several facets of behaviour, as judged by staff accompanying patients in the room, demonstrated desirable change over the session. Issues relating to refinement of the research methodology are discussed and the potential for such environments as tools for promoting communication is highlighted.
Spiritual high vs high on spirits: is religiosity related to adolescent alcohol and drug abuse?
Authors: Pullen  , Modrcin‐Talbott  , West  , Muenchen
Published: March 2003

This study investigated relationships between alcohol and drug abuse by adolescents and frequency of religious service attendance in the south‐east United States. Data obtained from surveys of 217 adolescents, age 12–19 years, was analysed. The adolescents included participants from both clinical and non‐clinical settings. Results from both groups showed that, as attendance at religious services increased, alcohol and drug abuse decreased. Spirituality is a concept that warrants further study to determine if its inclusion in treatment programs could enhance recovery or drastically reduce recidivism.
2. Absconding: how and when patients leave the ward
Authors: Davis Bryn , BOWERS L. , JARRETT M. , CLARK N. , KIYIMBA F. , MCFARLANE L.
Published: March 2003

Information about how and when patients abscond from acute psychiatric wards may provide important clues to effective prevention strategies. This paper reports relevant findings from a large scale study of absconding conducted in the East End of London. In contrast to the findings in previous studies, the vast majority of absconders left from the ward directly, mostly via the front door. Some were known to be at risk of absconding, and although more than half had declared their intention to leave, they still succeeded in getting away. On some occasions they circumvented locked or guarded doors, or special nursing observation. Shift handovers were a peak time for absconds, possibly due to decreased nursing surveillance of the ward. Most absconds occur during the first few weeks of admission, and most absconders simply went home and engaged in normal, everyday activities. The findings indicate that physical security measures alone are not a sufficient answer to the problem of absconding, and nurses need to work harder to develop supportive alliances with patients.
‘I don’t want to be a psychiatric nurse’: an exploration of factors inhibiting recruitment to psychiatric nursing in Ireland
Authors: Wells J. S. G. , Ryan D. , McElwee C. N.
Published: March 2003

Ireland has experienced a decline in recruitment to preregistration psychiatric nursing programmes (An Bord Altranais 1999). Social care workers often do similar psychosocial work with similar client groups served by psychiatric nurses. In marked contrast to psychiatric nursing, Irish social care diplomate and degree programmes are generally over subscribed. Yet graduates working in social care often experience inferiority in terms of pay, conditions and career structure compared to their psychiatric nursing counterparts (McElwee 1998). The question that therefore needs to be asked is why school leavers opt for such courses in preference to psychiatric nursing. This article describes the results of a pilot study, utilizing a focus group approach, to examine reasons for course and career choice among school leavers, psychiatric nursing students and social care students. Results indicate that school students rely on stereotypical views as part of their decisionmaking process in shaping occupational decisions. School students tend to conceptualize psychiatric nursing as being a job involving menial and physical tasks. Social care students saw psychiatric nursing as lacking autonomy and to be institutional in nature. Psychiatric nursing students themselves felt exploited and ‘second class’ compared to general nurses. Current recruitment campaigns and careers guidance within schools need to be more targeted on differentiating psychiatric nursing from its general nursing counterpart.
How do expert mental health nurses make on‐the‐spot clinical decisions? A review of the literature
Authors: Crook J. A.
Published: March 2003

An increasing number of writers have studied the work of Benner (1984) and
Schon (1983) and have explored the concepts of expertise and ‘intuitive’ or ‘tacit’ knowledge. Efforts have been made to address the phenomenon of the theory–practice gap. Reborn interest in the craft of the professions is evident. A number of studies about the clinical decision‐making process have suggested that clinicians are actually using a form of deductive reasoning known as hypothetico‐abductivism whilst reflecting in action. Exploration of expert decision‐making by psychiatric nurses requires first that the nature of psychiatric expertise be clearly described. However, literature shows that this is not an easy task. In order to facilitate the development of expertise in novice practitioners, further research is required into the nature of expertise and expert decision‐making. Cultivating and recording reflection in action around expert decision‐making has revealed greater insights into the gap between theory and practice. It is evident that there is a need for a model that makes sense of the informal theory that is generated through practice.
Mental health nurses’ PRN psychotropic medication administration practices
Authors: Usher K. , Lindsay D. , Sellen J.
Published: March 2003

PRN psychotropic medications (medications given with the aim of changing the patient’s mental state on an ‘as needed’ basis) are frequently prescribed and administered in mental health facilities. Their administration is largely an autonomous nursing role. However, little research has explored this important area of nursing practice in any detail and therefore the use of this intervention by mental health nurses is not fully understood. A descriptive project was undertaken to explore the factors involved in the administration of PRN psychotropic medications. It utilized a retrospective chart audit, conducted at one regional and one urban setting in Queensland, Australia. The results indicate a lack of clarity surrounding psychotropic PRN medication administration practices, confusion surrounding decision‐making processes related to this intervention, and poor documentation practices. The study found a high incidence of PRN psychotropic medication administration when compared to similar studies, and an excessive reliance on the use of typical antipsychotics over benzodiazepines. This practice is not supported by contemporary literature. As a result of our findings, we recommend further studies in areas of related importance, in order to increase our understanding of the complexities surrounding this important nursing intervention, and an investigation into documentation practices in inpatient mental health settings.
Power and control: forensic community mental health nurses’ perceptions of team‐working, legal sanction and compliance
Authors: Coffey Michael , Jenkins Emrys
Published: March 2003

This is the second of two papers reporting on a descriptive mixed methods study of community forensic mental health nurses’ experiences of restriction orders and supervised discharge mechanisms. Forensic community mental health nurses (FCMHNs) have a body of experience of working with mentally disordered offenders in the community. A number of these patients will be subject to conditions on discharge. This in effect acts as compulsory community treatment with the sanction of recall to hospital. This paper examines nurses’ perceptions of team‐working, legal powers and their effects upon compliance. Findings include that FCMHNs express general satisfaction with their input to decision‐making but some concerns were raised that challenge the ethic of team‐working. Respondents were broadly in favour of increased professional responsibility, although this may be related to a quest for status. A pragmatic if equivocal support for the use of compulsion in community mental healthcare was also expressed.
Compelled to interact: forensic community mental health nurses’ and service users’ relationships
Authors: Jenkins E. , Coffey M.
Published: March 2003

This is the first of two papers reporting community forensic mental health nurses’ experiences of restriction orders and supervised discharge mechanisms. Service user/nurse relationships and risk are addressed in this initial paper. A mixed method/approach was used. A piloted 15‐item questionnaire sought quantitative and qualitative data from 122 nurses throughout England and Wales; 57 questionnaires were returned. Limitations applying to gaining qualitative data via written questionnaire are overtly acknowledged. Quantitative data were analysed using the SPSS program. Content analysis and reflexive appraisal of qualitative data led to production of critically appraised conclusions. Findings are illustrative of complexity. Increased understanding of relevant issues, rather than definitive conclusions, is claimed as an outcome. Reductionist approaches are insufficient in illustrating relevant complexities; nurses offer considered, contextualized responses; diametrically opposed opinions exist about the value of interpersonal relationships and balances between care, control and risk assessment.
CARE: a framework for mental health practice
Authors: MCALLISTER M. , WALSH K.
Published: March 2003

Much has been written about care and its centrality to nursing practice. Yet nursing theories and frameworks surrounding care have either been esoteric or prescriptive and are seen as irrelevant to practice. This paper problematizes the notion of care with a view to developing a clearer, flexible framework for mental health practice. The framework is the product of the authors’ shared and individual experiences and theorizing as nurses and educators and has not yet been evaluated. The CARE framework (containment, awareness, resilience and engagement) is detailed, with examples of its use in practice. Using the framework offers a way for clinicians and carers to work more strategically with clients, helping them manage and understand their condition or disability, offering support to adapt and cope, and revealing and developing new or hidden strengths to help them endure the experience and find meaning for the recovery process. Taking up the framework within the everyday practice of mental healthcare offers several benefits for clients, clinicians and mental health.
Meanings of madness: a literature review
Authors: CASEY B. , LONG A.
Published: March 2003

This literature review focuses on how people make sense of mental illness. The study explores the process of meaning making by people experiencing mental ‘dis‐order’ as it is influenced by the context of their environments, available cultural explanations and the nature of their mental states at that time. It is proposed that people experiencing psychological trauma attempt to regain a sense of order by imposing a narrative structure on these disconcerting experiences. The sharing of these personal stories with others results in meanings being shaped and refined through dialogue and across time. Socially agreed meanings, however, can have a political dimension and it is argued that personal meanings embedded in narratives of mental pain are often suppressed and categorized to fit dominant cultural or biomedical explanations. Implications for mental health nursing are discussed.
Heart rate variability and apnea during sleep in Down's syndrome
Authors: FERRI RAFFAELE , CURZI‐DASCALOVA LILIA , DEL GRACCO STEFANO , ELIA MAURIZIO , MUSUMECI SEBASTIANO , PETTINATO SALVATORE
Published: March 2003

Autonomic system dysfunction has been reported to occur frequently in patients with Down's syndrome (DS) and is constituted mainly by an imbalance between the sympathetic and vagal systems. The analysis of heart rate variability (HRV) during sleep is a quantitative reliable method for studying such a mechanism, but it has not yet been extensively and adequately applied in DS. In this study, HRV during sleep was evaluated in seven DS patients and in six normal controls, by also controlling for the presence of sleep apnea or arousal. The main results were an increased sympathetic function (low‐frequency component of HRV) and a decreased vagal activity (high‐frequency component of HRV) in DS with respect to normal controls, during apnea‐free periods. Moreover, the presence of apnea, in DS, induced a further significant increase in low‐frequency and very low‐frequency components of HRV during sleep Stage 2. This study provides additional evidence of a brainstem dysfunctioning in DS, responsible for the abnormal imbalance between the sympathetic and vagal systems and confirms the brainstem involvement already suggested in the literature in order to explain brainstem‐auditory evoked potential abnormalities and central sleep apnea in these patients.
Eastward long distance flights, sleep and wake patterns in air crews in connection with a two‐day layover
Authors: LOWDEN ARNE , ÅKERSTEDT TORBJÖRN
Published: March 2003

The present study describes the spontaneous sleep/wake pattern in connection with an eastward (Stockholm to Tokyo,+8 h) transmeridian flight and short (51 h) layovers. To describe all sleep episodes and the recovery process across 4 days, and to relate adjustment to individual differences, 49 Scandinavian Airlines System (SAS) air crew were monitored for 9 days with activity monitors and sleep/wake diary before‐during‐after flight. The outbound flight involved a period of wakefulness extended to 21 h, frequently (87% of air crew) terminated by a long nap in Tokyo which was calm but difficult to wake up from. Then followed two night oriented sleep periods of normal length but of reduced efficiency, containing many and long awakenings. Napping was common during the extended periods of wakefulness, particularly during flights. During the recovery days, ease of rising from sleep in the mornings was difficult throughout, and feelings of not being refreshed returned to baseline levels on the third recovery sleep. Elevated daytime sleepiness (24% of the day) was observed on the first recovery day. No individual differences related to gender, age or position (cabin/pilot) was found in sleep strategy. Poor adjusters, subjects with a perceived lowered capacity on recovery days, showed more premature awakenings abroad and less refreshing sleep during the last 12 months, suggesting a decreased ability to cope with air crew scheduling. Comparisons with a westbound flight showed the eastbound flight layover sleep to be more problematic and containing more napping.
Sleep organization in the first year of life: Developmental trends in the quiet sleep–paradoxical sleep cycle
Authors: Ficca G. , Fagioli I. , Salzarulo P.
Published: March 2003

The night sleep of 48 healthy drug‐free infants, aged 1–54 weeks, was recorded and analysed in order to show how cycles contribute to sleep episode organization and how the balance among different sleep states (i.e. quiet sleep, paradoxical sleep and ambiguous sleep) within cycles changes as a function of age.

A greater proportion of time spent in cycles (TCT) on total sleep time (TST), as a result of the lengthening of sleep cycles, was found in older infants, whereas sleep out of cycles decreases with age. The internal structure of the sleep cycles also changes with age, because of the increase in the proportion of quiet sleep (QS), the appearance of slow wave sleep (SWS) from the 21st week onwards, and the decrease in ambiguous sleep. The proportion of paradoxical sleep (PS), however, remains stable throughout the first year of age.

The improvement of sleep organization across the first year of life is paralleled by an internal restructuring of the cycle, involving mainly changes in QS. We may speculate that both changes, one involving the lengthening of cycle and the other involving the increase in QS component, contribute to the improvement of biological and psychological sleep functions during development.
Prenatal protein malnourished rats show changes in sleep/wake behavior as adults
Authors: Datta Subimal , Patterson Elissa H. , Vincitore Michele , Tonkiss John , Morgane Peter J. , Galler Janina R.
Published: March 2003

Prenatal protein malnutrition significantly elevates brain levels of serotonin in rats, and these levels remain elevated throughout their lives. This biogenic amine is involved in the regulation of many physiological functions, including the normal sleep/wake cycle. The present study examined the effects of prenatal protein malnutrition on the sleep/wake cycle of freely moving adult rats. Six prenatally protein malnourished (6% casein) and 10 well‐nourished (25% casein) male rats (90–120‐day‐old) were chronically implanted with a standard set of electrodes (to record cortical electroencephalogram, neck muscle electromyogram, electrooculogram, and hippocampal theta wave) to objectively measure states of sleep and wakefulness. Six‐hour polygraphic recordings were made between 10.00 and 16.00 h; a time when the rats normally sleep. Prenatally malnourished rats spent 20% more time in slow wave sleep (SWS) compared to the well‐nourished rats. The total percentage of time spent in rapid eye movement (REM) sleep was 61% less in prenatally malnourished rats compared to well‐nourished control rats. These findings demonstrate the adverse consequences of prenatal protein malnutrition on the quality and quantity of adult sleep in rats. These sleep changes are potentially detrimental to normal social behavior and cognitive functions. Prenatally malnourished rats are an excellent animal model to study the role of endogenous serotonin in the regulation of the normal sleep/wake cycle.
Cyclic alternating pattern and spectral analysis of heart rate variability during normal sleep
Authors: Ferri Raffaele , Parrino Liborio , Smerieri Arianna , Terzano Mario G. , Elia Maurizio , Musumeci Sebastiano A. , Pettinato Salvatore
Published: March 2003

The natural arousal rhythm of non‐rapid eye movement (NREM) sleep is known as the cyclic alternating pattern (CAP), which consists of arousal‐related phasic events (Phase A) that periodically interrupt the tonic theta/delta activities of NREM sleep (Phase B). The complementary condition, i.e. non‐CAP (NCAP), consists of a rhythmic electroencephalogram background with few, randomly distributed arousal‐related phasic events. Recently, some relation between CAP and autonomic function has been preliminarily reported during sleep in young adults by means of spectral analysis of heart rate variability (HRV). The present study was aimed at analysing the effects of CAP on HRV in a group of normal children and adolescents. Six normal children and adolescents (age range 10.0–17.5 y) were included in this study. All‐night polygraphic recordings were performed after adaptation to the sleep laboratory. Six 5‐min epochs were selected from sleep Stage 2 and six from Stages 3 and 4 (slow‐wave sleep), both in CAP and NCAP conditions. From such epochs, a series of parameters describing HRV was then calculated, in both time and frequency domains, on the electrocardiographic R–R intervals. Statistical comparison between CAP and NCAP epochs revealed a significant difference for most of the frequency domain parameters (increase of the low‐frequency band, increase of the low‐frequency/high‐frequency ratio and decrease in the high‐frequency band during CAP) both in Stage 2 and in slow‐wave sleep. Our results demonstrate that the physiological fluctuations of arousal during sleep described as CAP are accompanied by subtle, but significant, changes in balance between the sympathetic and vagal components of the autonomic system.
Reported snoring – does validity differ by age?
Authors: Lindberg Eva , Elmasry Ahmed , Janson Christer , Gislason Thorarinn
Published: March 2003

Snoring is a major sign of obstructive sleep apnoea syndrome. Despite the frequent number of studies based on subjective reports of snoring, self‐reported snoring has hardly been validated at all. In some previous epidemiological studies, a significant association between snoring and cardiovascular morbidity and mortality was found only below the age of 50–60 y. This study was performed to investigate whether this is due to a decrease in the validity of reported snoring with increasing age. In a population‐based study, 2668 men aged 40–79 y answered a questionnaire including questions on snoring. Those who reported loud and disturbing snoring often or very often were regarded as habitual snorers. Without taking account of reported snoring, an age‐stratified sample of these men was selected and their snoring was measured using a microphone for 1 night. Significant snoring was defined as recorded snoring sounds for ≥ 10% of the night. The participants were divided into younger (age 40–59, mean ± SD: 51.8 ± 4.6 y, n=132) and older (age 60–79, 67.7 ± 5.4 y, n=99) age groups. When analysing the validity of reported snoring, no significant differences were found between the younger and older age groups in terms of specificity [younger: 82% (95% CI 74–90%), older: 88% (81–95%)] or sensitivity [younger: 40% (26–54%), older: 35% (17–53%)]. These data indicate that, in men aged 40–79 y, the validity of reported snoring is similar in different age groups. The lack of an association between reported snoring and cardiovascular disease at higher ages can, therefore, not be explained by a decrease in the validity of reported snoring.
Functional neuroimaging of normal human sleep by positron emission tomography
Authors: Maquet
Published: March 2003

Functional neuroimaging using positron emission tomography has recently yielded original data on the functional neuroanatomy of human sleep. This paper attempts to describe the possibilities and limitations of the technique and clarify its usefulness in sleep research. A short overview of the methods of acquisition and statistical analysis (statistical parametric mapping, SPM) is presented before the results of PET sleep studies are reviewed. The discussion attempts to integrate the functional neuroimaging data into the body of knowledge already acquired on sleep in animals and humans using various other techniques (intracellular recordings, in situ neurophysiology, lesional and pharmacological trials, scalp EEG recordings, behavioural or psychological description). The published PET data describe a very reproducible functional neuroanatomy in sleep. The core characteristics of this ‘canonical’ sleep may be summarized as follows. In slow‐wave sleep, most deactivated areas are located in the dorsal pons and mesencephalon, cerebellum, thalami, basal ganglia, basal forebrain/hypothalamus, prefrontal cortex, anterior cingulate cortex, precuneus and in the mesial aspect of the temporal lobe. During rapid‐eye movement sleep, significant activations were found in the pontine tegmentum, thalamic nuclei, limbic areas (amygdaloid complexes, hippocampal formation, anterior cingulate cortex) and in the posterior cortices (temporo‐occipital areas). In contrast, the dorso‐lateral prefrontal cortex, parietal cortex, as well as the posterior cingulate cortex and precuneus, were the least active brain regions. These preliminary studies open up a whole field in sleep research. More detailed explorations of sleep in humans are now accessible to experimental challenges using PET and other neuroimaging techniques. These new methods will contribute to a better understanding of sleep functions.
Fast track:Unilateral vibrissae stimulation during waking induces interhemispheric EEG asymmetry during subsequent sleep in the rat
Authors: Vyazovskiy V. , Borbély A. A. , Tobler I.
Published: March 2003

To test the theory that sleep is a regional, use‐dependent process, rats were subjected to unilateral sensory stimulation during waking. This was achieved by cutting the whiskers on one side, in order to reduce the sensory input to the contralateral cortex. The animals were kept awake for 6 h in an enriched environment to activate the cortex contralateral to the intact side. Whiskers are known to be represented in the barrel field of the contralateral somatosensory cortex and their stimulation during exploratory behavior results in a specific activation of the projection area. In the 6 h recovery period following sleep deprivation, spectral power of the nonrapid eye‐movement (NREM) sleep EEG in the 0.75–6.0 Hz range exhibited an interhemispheric shift towards the cortex that was contralateral to the intact whiskers. The results support the theory that sleep has a regional, use‐dependent facet.
SSRI Treatment suppresses dream recall frequency but increases subjective dream intensity in normal subjects
Authors: Pace‐Schott Edward F. , Gersh Tamara , Silvestri Rosalia , Stickgold Robert , Salzman Carl , Hobson J. Allan
Published: March 2003

Clinical lore and a small number of published studies report that the selective serotonin reuptake inhibitors (SSRIs) intensify dreaming. This study examines the dream effects of paroxetine and fluvoxamine in order to both increase clinical knowledge of these agents and to test an important potential method for probing the relationship between REM sleep neurobiology and dreaming in humans. Fourteen normal, paid volunteers (4 males, 10 females; mean age 27.4 year, range 22–39) free of medical or neuropsychiatric symptoms as well as of psychotropic or sleep affecting drugs completed a 31‐day home‐based study consisting of: 7 days drug‐free baseline; 19 days on either 100 mg fluvoxamine (7 Ss) or 20 mg paroxetine (7 Ss) in divided morning and evening doses; and 5 days acute discontinuation. Upon awakening, subjects wrote dream reports, self‐scored specific emotions in their reports and rated seven general dream characteristics using 5‐point Likert scales. Dream reports were independently scored for bizarreness, movement and number of visual nouns by three judges. REM sleep‐related measures were obtained using the Nightcap ambulatory sleep monitor. Mean dream recall frequency decreased during treatment compared with baseline. Dream report length and judge‐rated bizarreness were greater during acute discontinuation compared with both baseline and treatment and this effect was a result of the fluvoxamine‐treated subjects. The subjective intensity of dreaming increased during both treatment and acute discontinuation compared with baseline. Propensity to enter REM sleep was decreased during treatment compared with baseline and acute discontinuation and the intensity of REM sleep increased during acute discontinuation compared with baseline and treatment. The decrease in dream frequency during SSRI treatment may reflect serotonergic REM suppression while the augmented report length and bizarreness during acute SSRI discontinuation may reflect cholinergic rebound from serotonergic suppression.
Age‐related modifications of NREM sleep EEG: from childhood to middle age
Authors: Gaudreau H. , Carrier J. , Montplaisir J.
Published: March 2003

This study investigated the modifications in non‐rapid eye movement (NREM) sleep electroencephalogram (EEG) power in 54 subjects, from children to middle‐aged adults. Spectral analyses were performed on 5 h of NREM sleep. A marked decrease of absolute slow‐wave activity (SWA) was observed with increasing age; children had significantly more SWA than adolescents, young and middle‐aged adults. The decline of SWA across the night seems to level off with increasing age, suggesting an age‐related attenuation of homeostatic sleep pressure. Absolute theta power was higher for children compared with the other three groups, and adolescents had more theta power than young and middle‐aged adults. In comparison to young and middle‐aged adults, alpha power was higher for children and adolescents. Children and adolescents had more sigma power than middle‐aged adults. Absolute beta power was higher for children than for the other age groups. Therefore, the major alterations of NREM sleep EEG occurring between childhood and middle age are not restricted to SWA, but encompassed the theta, alpha, sigma and beta frequency bands.
Short‐term homeostasis of REM sleep assessed in an intermittent REM sleep deprivation protocol in the rat
Authors: OCAMPO‐GARCÉS ADRIÁN , VIVALDI ENNIO A.
Published: March 2003

An intermittent rapid eye movement (REM) sleep deprivation protocol was applied to determine whether an increase in REM sleep propensity occurs throughout an interval without REM sleep comparable with the spontaneous sleep cycle of the rat. Seven chronically implanted rats under a 12 : 12 light–dark schedule were subjected to an intermittent REM sleep deprivation protocol that started at hour 6 after lights‐on and lasted for 3 h. It consisted of six instances of a 10‐min REM sleep permission window alternating with a 20‐min REM sleep deprivation window. REM sleep increased throughout the protocol, so that total REM sleep in the two REM sleep permission windows of the third hour became comparable with that expected in the corresponding baseline hour. Attempted REM sleep transitions were already increased in the second deprivation window. Attempted transitions to REM sleep were more frequent in the second than in the first half of any 20‐min deprivation window. From one deprivation window to the next, transitions to REM sleep changed in correspondence to the amount of REM sleep in the permission window in‐between. Our results suggest that: (i) REM sleep pressure increases throughout a time segment similar in duration to a spontaneous interval without REM sleep; (ii) it diminishes during REM sleep occurrence; and (iii) that drop is proportional to the intervening amount of REM sleep. These results are consistent with a homeostatic REM sleep regulatory mechanism that operates in the time scale of spontaneous sleep cycle.
Regional cerebral blood flow during light sleep – a H215O‐PET study
Authors: Kjaer Troels W. , Law Ian , Wiltschiøtz Gordon , Paulson Olaf B. , Madsen Peter L.
Published: March 2003

This is the first report on the distribution of regional cerebral blood flow (rCBF) changes during stage‐1 sleep or somnolence. Two hypotheses were tested: (A) that rCBF differed between the awake relaxed state and stage‐1 sleep, (B) that hypnagogic hallucinations frequently experienced at sleep onset would be accompanied by measurable changes in rCBF using positron emission tomography (PET). Eight subjects were PET‐scanned with 15O‐labeled water injection in three conditions: awake, stage‐1 sleep with reportable experiences and stage‐1 sleep without reportable experiences. Electroencephalography (EEG) was performed continuously during the experiment. Sleep interviews were performed after each scan. The EEG was scored blindly to determine sleep stage. The sleep interviews revealed a substantial increase in how unrealistic and how leaping the thoughts were during stage‐1 sleep. During sleep there was a relative flow increase in the occipital lobes and a relative flow decrease in the bilateral cerebellum, the bilateral posterior parietal cortex, the right premotor cortex and the left thalamus. Hypnagogic experiences seemed not to be associated with any relative flow changes. The topography of the occipital activation during stage‐1 sleep supports a hypothesis of this state being a state of imagery. The rCBF decreases in premotor cortex, thalamus and cerebellum could be indicative of a general decline in preparedness for goal directed action during stage‐1 sleep. Stage‐1 sleep seems more similar to other forms of altered awareness, for example, relaxation meditation than to deeper sleep stages. We are of the opinion that stage‐1 sleep represents the dreaming state of wakefulness, while rapid eye movement (REM) sleep reflects the dreaming state of the unaware, sleeping brain.