bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariate analysis of risk factors in relation to TMD symptoms
Authors: YATANI H. , HATANAKA K. , MATSUKA Y. , MINAKUCHI H. , TOMONARI T.
Published: March 2003

The epidemiological studies on risk factors for temporomandibular disorders (TMD) are still extremely lacking. Therefore, their aetiological significance has scarcely been documented. The aim of this study was to quantitatively investigate the relationship between hypothesized risk factors and the precipitation and perpetuation of TMD symptoms.

The same 672 adults who participated in a previous study (Matsuka et al., 1996) were selected for this study. All subjects had already answered a self‐administered questionnaire and the same questionnaire was sent to them 4 years after the first survey. The questionnaire failed to reach 58 subjects at the second survey. Of the remaining 614 subjects, 367 (166 males and 201 females with a mean age of 53·1 ± 14·2 years) returned the questionnaire, for a return rate of 59·8%. Information about three TMD symptoms [temporomandibular joint (TMJ) pain, limitation of mouth opening, TMJ noise] was obtained from the questionnaire, and fluctuation of these symptoms was assessed by comparing three pairs of answers between the first and second surveys. Information about 18 hypothesized risk factors for TMD (age, sex, trauma, bruxism, malocclusion, oral habit, etc.) were also obtained from the questionnaire at the first survey. To evaluate how strongly each risk factor was associated with precipitation and perpetuation of TMD symptoms, odds ratio of each risk factors for precipitating or perpetuating TMD symptoms was calculated by means of logistic regression analysis.

Statistically significant risk factors for precipitating TMD symptoms were lip biting for TMJ pain (3·65) and trauma for limitation of mouth opening (3·20), and statistically significant risk factors for perpetuating TMD symptoms were female for TMJ pain (4·50) and TMJ noise (3·85) (odds ratio in parenthesis). The possible aetiological significance of these factors in TMD should be validated by future research.
Deformation/displacement of posterior digastric and sternocleidomastoid muscles during posterior digastric muscle palpation using magnetic resonance imaging and image processing procedure
Authors: SATO H. , MATSUGUMA T. , ISHIKAWA M. , KURAMOTO S. , UKON S. , ZEZE R. , KODAMA J.
Published: March 2003

Objective: As the process of palpation is basically subjective, the scientific evidence for masticatory muscle palpation, especially from an anatomical point of view, is scarce. Our previous study concerning the quantification of masseter muscle deformation during palpation using magnetic resonance imaging and image analysis procedure showed that masseter muscles are deformed and their fascia must be stretched during palpation (Ishikawa et al., Int J Prosthodont, in press). The aim of this study was to further evaluate the deformation/displacement of posterior digastric and sternocleidomastoid muscles during posterior digastric muscle palpation using almost the same procedure as in the previous study.

Subjects and methods: Subjects were 10 male volunteers with an average age of 26·8 years. MR images were taken using a 1·5 T scanner (MAGNEX 150 SHIMAZU Co. Ltd, Kyoto, Japan). Images were obtained on the axial plane with a spin‐echo, T1‐weighted technique using a head coil. At first, non‐compressed condition (control) was taken, then the continuously compressed condition of the bilateral posterior digastric muscle region using round plastic balls was taken. By superimposing a compressed image on a non‐compressed image, deformation/displacement was subjectively evaluated and measured using free image analysing software (NIH‐image).

Results and conclusion: Deformation of the bilateral posterior digastric muscle was difficult to identify, however, the average amount of displacement in medial direction was 9·0 ± 5·3 mm. Although we tried to compress posterior digastric muscles, sternocleidomastoid muscles were additionally deformed and displaced. The amount of medial displacement was 9·3 ± 4·7 mm. The values contained in our results exhibited fairly substantial variance. These findings suggest that masticatory muscle palpation is subjective and inconsistent.
Computer simulation of the occlusal anatomy of the first mandibular molar after varying the determinants of mandibular movement in the CICERO CAD/CAM system
Authors: OLTHOFF L.W. , DE RUITER W. , MEIJER I. , BOSMAN F.
Published: March 2003

Static and dynamic occlusal interferences often occur in restorations. The CICERO CAD/CAM technique was used to control the occlusal dimensions of all‐ceramic restorations by setting the variables which determine the mandibular contact movements. The anatomy of the occlusal form of the (pre)molar teeth is influenced by the setting of the sagittal and transversal determinants of mandibular contact movements.

In this study the variation in occlusal morphology of a high‐ and low‐limit setting of six variables was compared with an averaged setting. The settings (high, low and averaged, respectively) of the mandibular movement: the sagittal condylar (60°, 0°, 30°) and the incisal guide angle (60°, 0°, 30°) as well as the long centric articulation (1·2 mm, 0 mm, 0·6 mm) influence mainly the antero‐posterior direction, whereas the settings of Bennett movement (laterotrusion: 30°, 0°, 15°), Bennett side shift (laterotranslation: 1, 0, 0·5 mm) and the wide centric (lateral intercuspal contact area: 0·6, 0, 0·3 mm) will mainly influence the transversal direction of the mandibular movement.

The influence of the variation of settings on ‘dynamic’ crown morphology as compared with the static crown morphology was studied by comparison of mesio‐distal and bucco‐lingual sections at the same occlusal position of the first lower molar design. Furthermore, the amount of material needed for the correction of the ‘static’ crown to avoid interferences in dynamic conditions was calculated.

It appeared that most correction was needed for the ipsilateral settings: Bennett side shift (1·0 mm), Bennett movement (30°) and the Sag. Condylar guidance (0°) as well as the Incisal angle (0°), which could be studied in the bucco‐lingual sections. Also the Bennett side shift on the contra‐lateral side influenced the occlusal contour strongly, which could be seen in the mesio‐distal section.

It was concluded that simulation of the influence of several types of determinants of mandibular movement on the three‐dimensional occlusal anatomy can be studied using the CICERO‐CAD/CAM technique. The ipsi‐ and contralateral Bennett side shift variation influenced the occlusal anatomy more than other variables.
Functional impression and bite registration: a single session procedure for the construction of complete dentures
Authors: UTZ K. H. , MÜLLER F. , KETTNER N.
Published: March 2003

The closed‐mouth technique for the construction of complete dentures provides in the first session both impressions and a rough idea of the jaw relation in habitual intercuspation. The aim of this study was to apply this methodological advantage to the open‐mouth technique and to assess whether the arbitrary moulding of tooth position‐analogue plastic rims on functional impression trays facilitates a subsequent preliminary bite registration. Therefore, 104 complete dentures, manufactured by students during their final exams, were surveyed at 22 different test points using the Gutowski–Meyding gauge. Furthermore, the position of the front teeth, the lip support and the vertical dimension were assessed clinically.

The results were as follows

Upper complete denture

vertical distance: middle of ridge – incisal edge of central incisor: 13 ± 3 mm (5–21)

vertical distance: middle of ridge – tip of cusp of first molar: 9 ± 2 mm (2–16)

sagittal distance: middle of ridge – incisal edge of central incisor 7 ± 2 mm (3–14)

Lower complete denture

vertical distance: middle of ridge – incisal edge of central incisor: 12 ± 3 mm (7–19)

vertical distance: middle of ridge – tip of cusp of first molar: 13 ± 3 mm (5–20)

sagittal distance: middle of ridge – incisal edge of central incisor: 3 ± 2 mm (0–6)

Complete dentures in maximum intercuspation

vertical distance upper to lower ridge region central incisor 20 ± 4 mm (12–33)

vertical distance upper to lower ridge region first molar 21 ± 4 mm (9–34)

Because of the interindividual variance the arbitrary moulding of the tooth position‐analogue plastic rims seems not ideal. However, a functional and aesthetically pleasing existing denture should be surveyed to pre‐shape functional impression trays. Such individualized trays proved clinically a valuable tool for functional impressions and an immediate preliminary bite registration.
First night effect of an interocclusal appliance on nocturnal masticatory muscle activity
Authors: Hiyama S. , Ono T. , Ishiwata Y. , Kato Y. , Kuroda T.
Published: March 2003

summary  The purpose of this study was to examine the effect of an interocclusal appliance on nocturnal masticatory muscle activities. Six healthy Japanese males (mean age: 26·8 years) participated in this study. Electromyographic (EMG) activities of the right anterior temporalis and masseter muscles were recorded using a portable EMG recording unit at night both with and without an interocclusal appliance. In both muscles, the maximal EMG activity and the number of bruxing events decreased significantly by wearing the appliance. Moreover, the duration of a higher level of muscle activity was decreased while that of a lower level of muscle activity increased by wearing the appliance in both muscles. These findings suggest that nocturnal masticatory muscle activity is significantly reduced by wearing an interocclusal appliance, and that the use of such an appliance at night could help to relax masticatory muscles.
Fracture reasons in ceramic‐fused‐to‐metal restorations
Authors: Özcan M.
Published: March 2003

summary  Ceramic‐fused‐to‐metal restorations are widely used in dentistry with a high degree of general success. Fracture of the ceramic veneers as a result of oral function or trauma is not an uncommon problem in clinical practice. Although fractures of such restorations do not necessarily mean the failure of the restoration, the renewal process is both costly and time consuming and therefore remains a clinical problem. Fractures in the anterior region pose an aesthetic problem but when they are in the posterior, chewing function could also be affected. The published literature reveals that reasons for failures cover a wide spectrum from iatrogenic factors to laboratory mistakes or because of factors related to the inherent structure of the ceramics or simply to trauma.
Disentangling dynamics: group sensitivity and supervision
Authors: Winship  , Hardy
Published: March 2003

In order to contextualize Altschul's interest in group dynamics we present a brief history of staff group work approaches in the UK and USA. Using case examples, the work of staff group sensitivity and group supervision is described. The difficulties of working in staff groups are highlighted and the antipathy towards group practice is discussed. It is argued that learning about conflict resolution in staff groups prepares nurses for dealing with conflicts in clinical practice. The case for re‐invigorating interest in group theory and practice is presented. In presenting our reflections on staff group work, we hope not only to re‐kindle the type of interest in groups that inspired Altschul but also to re‐present the case that it is ill conceived to attempt the work of mental health nursing without recourse to the supervisory resources of group theory, practice and support. It is through group feedback that mental health nurses and other health professionals can extend their learning about interpersonal relations, achieve quality standardization through peer feedback and reflect on practice in truly collaborative ways ( Schon 1983).
An exploratory account of registered nurses' experience of patient aggression in both mental health and general nursing settings
Authors: DUXBURY J.
Published: March 2003

Until relatively recently, aggression and violence in nursing has been an area of little discussion (Poster & Ryan 1993). Today, concerns are rising about escalating levels of violence towards nurses (Wykes 1994, Whittington 1997). In response, this paper explores registered nurses' experiences of patient aggression encountered in the acute inpatient general and mental health settings. Critical incidents from registered nurses in both areas are examined and analyzed in relation to existing literature. The aim of the research is to ascertain if differences exist or similarities prevail. Findings reveal that the two areas have similar problems in terms of types of aggression. Verbal and ‘minor’ types of aggression are the most problematic. Also, the ‘biomedical model’ of care is evident in both settings and possibly underpins chosen approaches to aggression management. The repeated use of chemical and physical restraint is apparent. The main comparison identified between the two groups relates to nursing control over situations involving violent patients. Mental health nurses seem to consistently take control of aggressive situations whilst general nurses tend to rely more heavily upon the input of others (medical staff, mental health teams and the police) when intervening. These two nursing specialties therefore have much to learn from each other in terms of nursing experience and possible future approaches to the management of aggressive patients.
The Phil Hearne course: an evaluation of a multidisciplinary mental health education programme for clinical practitioners
Authors: Parsons S. , Barker P.
Published: March 2003

A description and evaluation of the pilot of a 30‐week multidisciplinary mental health education programme (The Phil Hearne Course) is presented. The course was based upon the expressed service needs of an NHS Trust and upon the needs of users consulted during the developmental phase of the project. The course was designed to provide core skills, relating to effective assessment, communication, intervention and networking. These skills were thought to be applicable to all mental health disciplines. The course was evaluated positively by students and staff and was found to be effective in improving practice by providing a range of core skills for mental health workers. It was also determined that students tended to over‐estimate their skills in core areas, particularly care planning and record‐keeping. It is intended to develop the course into a distance learning, skills‐based package.
Nurse behavioural psychotherapy and pathological gambling: an Australian perspective
Authors: Tolchard B. , Battersby M.
Published: March 2003

Nurses have been employed as behavioural psychotherapists for over 25 years. The first training in this field was established at The Maudsley Hospital ( Marks et al. 1977
). Since then there have been a number of courses producing many specialist nurse behavioural psychotherapists (NBTs) (
Duggan et al. 1993
). Nurse behavioural therapy is taken to mean nurses working as behavioural psychotherapists. This title does not mean they are practising a separate form of therapy from other professionals such as psychologists. In Australia there is no such training, with nurse behavioural psychotherapists working here having trained first in UK. Initially NBTs were trained to treat people with anxiety disorders. Over the past 25 years this emphasis has remained, but many NBTs have gone on to provide help to people with other problems. This paper will demonstrate the practical application of behavioural psychotherapy with problem gamblers, and how specialist trained nurses can provide such treatment. The paper will look briefly at nurse behavioural psychotherapy from its initial inception to its current status in Australia. The outcomes of the treatment programme carried out at Flinders Medical Centre for Problem Gamblers will be discussed with a view to nurses carrying out therapy. Finally, the future of nurse behavioural psychotherapy in Australia and how nurses can apply such skills across a wide range of problems, including gambling, will be reviewed.

Aspects of this paper were first presented to the 7th NAGS conference, Adelaide 1996.
Staff development, anxiety and relaxation techniques: a pilot study in an acute psychiatric inpatient setting
Authors: Dodd H. , Wellman N.
Published: March 2003

Psychiatric inpatients often complain of problems with anxiety, but a computerised search of the nursing literature failed to find any publications detailing nurse‐led, individual or group anxiety management work specifically aimed at psychiatric inpatient populations. In the UK, psychiatric inpatient populations are characterized by people with clinical diagnoses of schizophrenia and major affective and personality disorders. This is a very different population from that treated in the vast majority of published trials of cognitive and other approaches to anxiety management. A pilot study was conducted on four psychiatric acute admission wards to determine the practicality of treating a convenience sample of psychiatric inpatients with self‐reported anxiety problems along broadly cognitive lines. Patients attended a course of three anxiety management groups (AMGs) run by nurses and were given homework and other exercises to complete. Patients reported significant reductions in anxiety after completion of the treatment. The AMGs were facilitated by staff nurses under the supervision of a clinical nurse specialist, and not by fully trained therapists as in most treatment studies relating to anxiety. Further studies, particularly randomized controlled trials, are needed to explore the efficacy and practicality of nurses delivering brief psychological interventions to psychiatric inpatients.
Medication compliance in older individuals with depression: gaining the views of family carers
Authors: Boyle E. , Chambers M.
Published: March 2003

Documented evidence indicates that medication non‐compliance for the older person is a common and poorly understood problem. This paper reports on a pilot study, which used a focus group interview to explore carers' attitudes, experiences and perceptions regarding medication compliance for their older depressed relative. It aimed to understand the problems and challenges encountered by carers in respect of their relative being non‐compliant, and provide material to develop a comprehensive educational and support package to promote antidepressant compliance. A convenience sample of seven carers participated in the focus group and a qualitative analysis of the interview identified a number of key issues. Carers had little knowledge of depression, they were not well informed regarding antidepressant medication and they took an active role to ensure compliance. The focus group highlighted the need for health care professionals to promote and encourage carers to be part of the older individuals treatment programme and provide concise and unambiguous educational information in relation to antidepressants and the importance of compliance.
Nurses' perceptions of multidisciplinary teamwork in acute psychiatric settings
Authors: Barker P. J. , Walker L.
Published: March 2003

The findings of a pilot telephone survey of senior nurses' views of multidisciplinary teamwork (MDT) practice in 26 acute psychiatric admission wards within the ambit of one English health authority are reported. The survey was conducted in two stages. The first stage focused on obtaining the senior nurse's general perceptions of the organization of the work of the multidisciplinary team, and in the second stage more detailed responses to the original questions were obtained. The findings suggest that the composition and operations of the acute ward team are limited, and the relationship between the MDT and patients and their families do not entirely support the concept of increased collaboration with patients and their families. The findings are discussed within the context of the perceived crisis in acute psychiatric care in England and the ambitions for more egalitarian ‘mental health’ services.
Interventions in the nurse–patient relationship in forensic psychiatric nursing care: a Swedish survey
Authors: Rask M. , Levander S.
Published: March 2003

Nurses (Registered nurses, RN, and Licensed Mental Nurses, LMN) working in five Swedish forensic psychiatric units filled in a questionnaire designed for general psychiatric nursing, but modified for forensic use. In this report, data concerning the extent to which treatment interventions included verbal elements, and the focus of these nurse–patient verbal interactions, were analysed. The most commonly used interventions were ‘social interaction’, ‘regular communication’ and ‘social skills training’. The most common focus in verbal nurse–patient interaction were ‘explaining consequences, confronting and encouraging the patient to talk about his/her crime/behaviour’, ‘interpretative communications with the patient’, and ‘communication about functions in daily life’. The salient findings were: (1) seven of the fifteen interventions used by the nurses included verbal elements to a great extent; (2) nurses often used confronting interventions, despite the fact that the large EE (expressed emotion) literature suggest that hostility and critical remarks may provoke a worsening of symptoms among psychotic patients; (3) there was only little correspondence between actual practice and theoretical models; and (4) there were unexpectedly small differences between the two professional groups (RN and LMN), suggesting that the roles are not distinct.
What are the principles and processes of inspiring hope in cognitively impaired older adults within a continuing care environment?
Authors: Cutcliffe J. R. , Grant G.
Published: March 2003

This study focuses on the principles and processes that psychiatric/mental health (P/MH) nurses use to inspire hope in cognitively impaired older adults within a National Health Service (NHS) continuing care environment. Using a grounded theory method, the data were coded and analysed, in an attempt to produce an integrated conceptual framework of hope inspiration. This comprised four core variables: applied humanistic code, pragmatic knowledge, interpersonal relations and nurse as utilizer. The authors postulate a relationship between the function of caring, the activity of helping and the practice of instilling hope, as a basis for suggesting that inspiring hope to clients is one of the primary acts of P/MH nursing. The authors conclude that the four core variables are intertwined and inseparable from one another, and bound up with P/MH nursing practice. From this position, it is suggested that the processes of inspiring and instilling hope cannot be separated from the qualities of being a P/MH nurse. However, a more detailed and complete understanding of the concept of hope can increase the nurse's effectiveness as a carer.
Towards a ‘forensic lens’ model of multidisciplinary training
Authors: Mason Tom , Carton Gerry
Published: March 2003

This paper reports on research undertaken to identify if common areas of multidisciplinary training exist in the literature. The literature that specifically focused on training issues in forensic practice (mental health) was located and reviewed by coding analysis. Thirteen common areas were identified and approximately 250 content items were acknowledged. A ‘forensic lens’ model was established to provide a framework in which multidisciplinary training could be located. Further research is promulgated to establish the actual importance of each training area for specific forensic disciplinary groups.
The siesta culture concept is not supported by the sleep habits of urban Mexican students
Authors: VALENCIA‐FLORES MATILDE , CASTAÑO VIOLETA , CAMPOS ROSA , ROSENTHAL LEÓN , RESENDIZ MONTSERRAT , VERGARA PATRICIA , AGUILAR‐ROBLERO RAÚL , GARCÍA RAMOS GUILLERMO , BLIWISE DONALD
Published: March 2003

Evidence in support for the concept of the so‐called ‘siesta culture’ is not well developed and has, to date, relied largely on qualitative anthropological data. Presumably such cultures are characterized by a strong tendency for daytime naps and daytime sleepiness, phenomena which may partially represent the effects of geographic, climatic or light conditions and/or cultural influences. In this study we surveyed the nocturnal sleep habits and daytime sleep tendencies of 577 Mexican college students residing in Mexico City (19°N latitude). Results indicated a number of parallels between the reported sleep habits of these students and those reported from other cultures at latitudes far to the north (North America, Europe), such as longer sleep at the weekends, an association between snoring and daytime sleepiness and a lack of relationship between nocturnal sleep duration and the reported tendency to nap. There was some suggestion that these Mexican students may actually nap less when compared to other college student populations. Taken together, these results call into question what is meant by the concept of a ‘siesta culture’, at least in this urban, educated, upper social economic scale (SES) population, and suggest that future studies in equatorial regions be undertaken to further appreciate the role of climate, photoperiod and/or culture in the tendency for humans to nap during the day.
Fatal familial insomnia: clinical features and molecular genetics
Authors: Cortelli  , Gambetti  , Montagna  , Lugaresi
Published: March 2003

Fatal familial insomnia (FFI) is an autosomal dominant prion disease clinically characterized by inattention, sleep loss, dysautonomia, and motor signs and pathologically characterized by a preferential thalamic degeneration. FFI is linked to a missense mutation at codon 178 of the prion protein gene, PRNP, coupled with the presence of the codon methionine at position 129, the locus of a methionine‐valine polymorphism. Homozygotes at codon 129, expressing methionine also in the nonmutated allele, have a shorter disease course (often less than 1 year), prominent sleep and autonomic disturbances at disease onset, and pathology restricted to the thalamus. Heterozygotes at codon 129, expressing valine in the nonmutated allele, have a longer disease course (often longer than 1 year), ataxia and dysarthria at disease onset, and lesions widespread to cerebral cortex. Both in the thalamus and in the cortex, the limbic structures are those most consistently and severely involved: the anterior ventral and mediodorsal thalamic nuclei, the cingulate gyrus, and the orbitofrontal cortex. FFI is thus a prion disease selectively damaging the thalamocortical limbic structures. Loss of sleep, sympathetic hyperactivity, and flattening of vegetative and hormonal circadian oscillations characterize FFI and result from a homeostatic imbalance caused by the interruption of the thalamocortical limbic circuits, the phylogenetically most advanced structures involved in the control of the sleep–wake cycle and the body’s homeostasis. The selective atrophy of the limbic thalamus that characterizes FFI might be due to the binding of FFI toxic PrP or PrPres to specific receptors on thalamolimbic neurons.
The N550 component of the evoked K‐complex: A modality non‐specific response?
Authors: Colrain Ian M. , Webster Kate E. , Hirst Giles
Published: March 2003

A large amplitude late negative deflection peaking between 500 and 650 ms is observable in the averaged K‐complex wave‐form. This peak is thus often labelled the N550. ‘N550’ appears during stage 2 and is maintained into slow wave sleep but is not apparent during REM. Most studies have employed auditory stimuli to elicit the K‐complex. Two experiments were run to examine the effects of stimulus modality on the topographical distribution of the N550. In the first experiment, the K‐complexes were elicited in an auditory oddball procedure. In the second experiment, K‐complexes were elicited by respiratory occlusions. Twenty‐nine channel recordings were used to increase spatial resolution. N550 was substantially larger in the average of trials containing K‐complexes than in trials in which a K‐complex could not be identified. N550 varied inversely in amplitude with the probability of accordance of the stimulus. The topographic distribution of the N550 was consistent between experiments. It was bilaterally symmetrical and was maximal over fronto‐central regions of the scalp. The results indicate that the N550 reflects the activity of a modality non‐specific, sleep dependent generator that responds to both interoceptive and external stimulation.
Relations among hypnagogic and hypnopompic experiences associated with sleep paralysis
Authors: Cheyne J. Allan , Newby‐Clark Ian R. , Rueffer Steve D.
Published: March 2003

The Waterloo Sleep Experiences Scale was developed to assess the prevalence of sleep paralysis and a variety of associated hypnagogic and hypnopompic hallucinoid experiences: sensed presence, felt pressure, floating sensations, auditory and visual hallucinations, and fear. Consistent with results of recent surveys, almost 30% of 870 university students reported at least one experience of sleep paralysis. Approximately three‐quarters of those also reported at least one hallucinoid experience, and slightly more than 10% experienced three or more. Fear was positively associated with hallucinoid experiences, most clearly with sensed presence. Regression analyses lend support to the hypothesis that sensed presence and fear are primitive associates of sleep paralysis and contribute to the elaboration of further hallucinoid experiences, especially those involving visual experiences.
Quantifying the performance impairment associated with fatigue
Authors: Lamond Nicole , Dawson Drew
Published: March 2003

The present study systematically compared the effects of fatigue and alcohol intoxication on a range of neurobehavioural tasks. By doing so, it was possible to quantify the performance impairment associated with fatigue and express it as a blood alcohol impairment equivalent. Twenty‐two healthy subjects aged 19–26 years participated in three counterbalanced conditions. In the sustained wakefulness condition, subjects were kept awake for 28 h. In the alcohol and placebo conditions, subjects consumed either an alcoholic or non‐alcoholic beverage at 30 min intervals, until their blood alcohol concentration reached 0.10%. In each session, performance was measured at hourly intervals using four tasks from a standardised computer‐based test battery. Analysis indicated that the placebo beverage did not significantly effect mean relative performance. In contrast, as blood alcohol concentration increased performance on all the tasks, except for one, significantly decreased. Similarly, as hours of wakefulness increased performance levels for four of the six parameters significantly decreased. More importantly, equating the performance impairment in the two conditions indicated that, depending on the task measured, approximately 20–25 h of wakefulness produced performance decrements equivalent to those observed at a blood alcohol concentration (BAC) of 0.10%. Overall, these results suggest that moderate levels of fatigue produce performance equivalent to or greater than those observed at levels of alcohol intoxication deemed unacceptable when driving, working and/or operating dangerous equipment.
The role of the spindle in human information processing of high‐intensity stimuli during sleep
Authors: Cote Kimberly A. , Epps TinA. M. , Campbell Kenneth B.
Published: March 2003

Sleep spindles are 12–14 Hz oscillations in EEG, which are thought to inhibit or ‘gate’ information processing. Event‐related potentials may be employed to probe the extent of information processing during sleep. Previous research indicates that event‐related potentials elicited by moderate intensity stimuli show increased positivity (or further removal of negativity) when stimuli are presented concurrent with spindles. However, the effectiveness of spindles to inhibit the processing of much louder stimuli remains unknown. The purpose of the present study was to investigate the extent of this gating, by using a range of stimuli including those that are loud and intrusive. Eight good sleepers were recorded during a single night. Auditory stimuli were delivered randomly at 0, 60, 80 or 100 dB SPL. Trials were sorted off‐line by sleep stage, stimulus intensity and spindle characteristic (i.e. spindle absent, spindle present). During the sleep‐onset period, the often‐reported changes in event‐related potentials were observed – N1 decreased and P2 increased in amplitude. In Stage 2 sleep, P2 was affected by the presence of spindles, particularly when stimulus intensity was loud. Its amplitude was greatest when spindles occurred following the onset of the stimulus. Scalp‐recorded spindles might, therefore, be a consequence of the prior thalamic inhibition of information processing, especially when confronted by loud, intrusive external stimuli.
The ability to self‐monitor performance when fatigued
Authors: Dorrian Jill , Lamond Nicole , Dawson Drew
Published: March 2003

The present study aimed to systematically investigate the effects of elevated fatigue levels on the ability to self‐monitor performance. Eighteen participants, aged 19–26 y, remained awake for a period of 28 h. Neurobehavioural performance was measured at hourly intervals using four tests from a standardized computer test battery. From these four tests, six measures of performance were obtained: grammatical reasoning (accuracy and response latency); vigilance (accuracy and response latency); simple sensory comparison and tracking. In addition, before and after each test, participants completed visual analogue scales which required them to rate their alertness level and the speed and accuracy of their performance. Individual test results for both self‐ratings and neurobehavioural performance were converted to z‐scores. Planned comparison analysis indicated that scores on four of the six performance measures decreased significantly as hours of wakefulness increased. Similarly, predicted performance scores for all six measures of performance decreased significantly. Analysis revealed moderate correlations between predicted and actual performance for the four parameters affected by fatigue. Furthermore, moderate to high correlations were found between all six performance parameters and their respective post‐test self‐ratings. In addition, moderate to high correlations were found between predicted performance and alertness. Taken together, these findings suggest that as fatigue levels increase, subjects globally assess performance decrements. Results suggest that subjective alertness may in part mediate an individual’s global assessment of performance.
Naso‐oesophageal probes decrease the frequency of sleep apnoeas in infants
Authors: Groswasser  , Scaillon  , Rebuffat  , Simon  , De Groote  , Sottiaux  , Kahn
Published: March 2003

The objective of the study was to determine whether a naso‐oesophageal probe modifies sleep and cardiorespiratory patterns in infants with repeated obstructive apnoeas. Two polygraphic recording sessions were conducted in random order for 2 nights on 35 infants suspected to have repeated obstructive sleep apnoeas. One sleep study was performed with a pH probe inserted through the nasal passage down to the distal portion of the oesophagus. The other session was conducted without any naso‐oesophageal probe (the baseline study). For the 25 infants who presented repeated obstructive apnoeas during baseline studies, the presence of the probe was associated with a small, but significant, decrease in the number of central apnoeas (median frequency of 18.5 apnoeas per hour without a probe; 16.1 per hour with the probe; P=0.040), and obstructive apnoeas (median of 1.9 apnoeas per hour without a probe; 0.6 per hour with the probe; P=0.016). The presence of the probe was also associated with a small increase in percentage non‐rapid eye movement (NREM) sleep frequency. The changes were statistically significant only for infants who had no obstructive apnoea during baseline studies (29 vs. 31%). The presence of a naso‐oesophageal probe significantly modifies the infants’ respiratory characteristics during sleep. These findings should be considered when reporting and interpreting sleep studies in infants.
Increased sodium–proton antiporter activity in patients with obstructive sleep apnoea
Authors: Tepel Martin , Sanner Bernd M. , Van Der Giet Marcus , Zidek Walter
Published: March 2003

Cytosolic pH (pHi) and the activity of the sodium–proton antiporter (Na+/H+ antiporter) were measured in lymphocytes from 22 patients with obstructive sleep apnoea and from 24 age‐matched healthy subjects (Controls). The cellular Na+/H+ antiporter was measured spectrophotometrically using a pH‐sensitive fluorescent dye after intracellular acidification using sodium propionate. Resting pHi was similar in lymphocytes from patients with obstructive sleep apnoea and from controls (7.36 ± 0.20, n=22; vs. 7.35 ± 0.19, n=24; mean ± SD). The Na+/H+ antiporter activity was significantly higher in patients with obstructive sleep apnoea than in controls (11.87 ± 3.26 × 10–3 pHi/s vs. 4.38 ± 1.40 × 10–3 pHi/s; P < 0.0001). The apparent affinity of the Na+/H+ antiporter was not significantly different between the groups (6.90 ± 0.23 vs. 6.87 ± 0.20). In patients with obstructive sleep apnoea the activity of the Na+/H+ antiporter remained stable during the night. The activity of the Na+/H+ antiporter was 13.49 ± 4.80 × 10–3 pHi/s at 20.00 and 13.26 ± 6.13 × 10–3 pHi/s at 02.00. From the present results it is concluded that an increased cellular Na+/H+ antiporter activity may be a genetic marker for patients who are predisposed to obstructive sleep apnoea.
Tongue protrusion strength and fatiguability: Relationship to apnoea/hypopnoea index and age
Authors: Mortimore Ian L. , Bennett Stephen P. , Douglas Neil J.
Published: March 2003

The sleep apnoea/hypopnoea syndrome (SAHS) is characterized by retroglossal or retropalatal narrowing. The site of obstruction, and the fact that negative pressure in the upper airway increases retroglossal airway size, suggests that tongue muscles may play a role in the maintenance of upper airway patency. We therefore hypothesized that tongue protrusion strength and fatiguability may be predictors of apnoea/hypopnoea index, vary with age and may be different in SAHS patients and normal subjects. Maximal strength (Fmax) and fatiguability (measured as the total time subjects were able to maintain 50% Fmax on three consecutive occasions separated by 30 s) were assessed using a force transducer in 98 consecutive apnoeic/hypopnoeic male patients referred to our laboratory for sleep studies [apnoea/hypopnoea index (AHI) range 3–130/h, age range 30–74 y]. Fmax and fatiguability were also compared in 15 male SAHS patients (mean AHI 20/h) and 15 nonsnoring male subjects matched for age, body mass index and fat free mass. A further 26 SAHS patients had tongue protrusion strength/fatiguability measured before, during and after a night’s sleep. Log AHI was only weakly correlated with Fmax (r=− 0.21; P=0.03) and age (r=0.23; P=0.025), but not to fatiguability (P > 0.05). Comparison between SAHS and nonsnoring subjects did not demonstrate significant differences in Fmax (P=0.1) or fatiguability (P=0.1). There was no evidence of a change in muscle strength (P > 0.05) or fatigue (P > 0.05) during the course of a night’s sleep. We conclude that tongue protrusion strength and fatiguability are unlikely to be important factors in the pathogenesis of SAHS.
The effect of sleep fragmentation on cognitive processing using computerized topographic brain mapping
Authors: Kingshott Ruth N. , Cosway Richard J. , Deary Ian J. , Douglas Neil J.
Published: March 2003

Topographic brain mapping of evoked potentials can be used to localize abnormalities of cortical function. We evaluated the effect of sleep fragmentation on brain function by measuring the visual P300 waveform using brain mapping. Eight normal subjects (Epworth Score ± SD: 5 ± 3) underwent tone‐induced sleep fragmentation and undisturbed study nights in a randomized cross‐over design. Study nights were followed by topographic brain mapping using a visual information processing test and concurrent event‐related potentials. Experimental sleep fragmentation did not significantly increase objective daytime sleepiness or lower cognitive performance on a battery of cognitive function tests (all P ≥ 0.1). There were no significant topographical delays in P300 latencies with sleep fragmentation (all P > 0.15). However, at sites Fz, F4, T3, C3, Cz and C4 the P300 amplitudes were reduced significantly after sleep fragmentation (all P < 0.05). A reduction in P300 amplitude has previously been interpreted as a decrease in attention. These reductions in P300 amplitudes with sleep fragmentation in frontal, central and temporal brain areas suggest that sleep fragmentation may cause a broad decrease in attention. Sleep fragmentation did not delay P300 latencies in any brain area, and so does not explain the delay in P300 latencies reported in sleep apnoeics.
Sleep complaints and risk factors for excessive daytime sleepiness in adult males in Northern Ireland
Authors: Nugent A. M. , Gleadhill I. , Mccrum E. , Patterson C. C. , Evans A. , Macmahon J.
Published: March 2003

The prevalence of sleep complaints in Northern Ireland is unknown. Sleep disruption can result in excessive daytime sleepiness (EDS), with significant socioeconomic consequences. The aim of this study was to assess the prevalence of sleep complaints and to determine risk factors for EDS in a Northern Irish community. From an urban and rural community of 499 111 people, a random sample of 3391 adult men were sent a questionnaire by mail. Questions were asked regarding sleep, EDS and medical history. There were 2364 completed questionnaires returned (response rate 70%). The mean age of respondents was 46.0 years (range 18–91 years). 26.7% of men were not satisfied with their usual night’s sleep and 68% of men woke up at least once during the night. Based on pre‐defined criteria, 24.6% of the population had insomnia and 19.8% had EDS. The strongest risk factor identified for EDS was a history of snoring loudly (odds ratio 2.62; 95% CI 1.82–3.77). Other risk factors included ankle swelling, feeling sad or depressed stopping sleep, experiencing vivid dreams while falling asleep, waking up feeling unrefreshed and age > 35 years. The prevalence rates of sleep complaints and EDS in this community‐based study is high, although this does depend directly on the criteria used to define insomnia and EDS. Recognition of risk factors for EDS may help to identify and treat those affected.
P300 and sleep‐related positive waveforms (P220, P450, and P900) have different determinants
Authors: Hull John , Harsh John
Published: March 2003

Stimulus factors known to influence the amplitude of the well known endogenous event‐related potential (ERP) component P300 were manipulated to determine whether they have the same, or a different, influence on the amplitude of positivities of the sleep ERPs identified as P220, P450, and P900. Behavioral responsiveness and ERPs were recorded as subjects moved from wakefulness to sleep while performing an oddball task. The task consisted of sequential presentation of target and non‐target tone stimuli with instructions to respond to targets with a finger–lift response. The probability of the target and non‐target stimuli was varied (0.2/0.8, 0.5/.05 and 0.8/0.2) across three test conditions. While subjects were awake, P300 was maximal parietally with amplitude inversely related to the relative probability of the evoking stimulus and directly related to its task relevance. Positive waveforms (P220, P450, P900) recorded in sleep were largest at frontal and central recording sites. P220 and P900 amplitudes were inversely related to stimulus probability. P220 was smaller following target relative to non‐target stimuli. Processes underlying P220, P450, and P900 sleep‐related waveforms are different from those underlying the P300 component seen in alert wakefulness. The sleep positivities may be state‐related waveforms subject to modulation by psychological processes.
Neurological impairments and sleep–wake behaviour among the mentally retarded
Authors: Lindblom Niki , Heiskala Hannu , Kaski Markus , Leinonen Lea , Nevanlinna Antti , Iivanainen Matti , Laakso Maija‐Liisa
Published: March 2003

The objective of the present study was to evaluate the relationship between the sleep–wake behaviour and neurological impairments among mentally retarded people. The sleep–wake behaviour of 293 mentally retarded subjects living in a rehabilitation center was studied by a standardized observation protocol carried out by trained staff members. The protocol consisted of brief check‐ups of the subjects’ sleep–wake status at 20‐min intervals for five randomly chosen 24‐h periods during 4 months. From the raw data five sleep–wake behaviour variables were formed. The data concerning the subject characteristics (age, body mass index (BMI), gender, degree of mental retardation, presence of locomotor disability, that of epilepsy, blindness or deafness and the usage of psychotropic medications) were collected from the medical records. Two main findings emerged: (1) severe locomotor disablity, blindness and active epilepsy were found to be independent predictors of increased daytime sleep and increased number of wake–sleep transitions and (2) the subjects with a combination of two or all three of these impairments had a significantly more fragmented and abnormally distributed sleep than those with none or milder forms of these impairments. Age, BMI, degree of mental retardation and the studied medications played a minor role in the sleep disturbances of the study population. Finally, deafness was not found to be associated with any of the measured sleep–wake variables.
The effects of 1 week of REM sleep deprivation on parvalbumin and calbindin immunoreactive neurons in central visual pathways of kittens
Authors: Hogan Dale , Roffwarg Howard P. , Shaffery James P.
Published: March 2003

Many maturational processes in the brain are at high levels prenatally as well as neonatally before eye‐opening, when extrinsic sensory stimulation is limited. During these periods of rapid brain development, a large percentage of time is spent in rapid eye movement (REM) sleep, a state characterized by high levels of endogenously produced brain activity. The abundance of REM sleep in early life and its ensuing decline to lower levels in adulthood strongly suggest that REM sleep constitutes an integral part of the activity‐dependent processes that enable normal physiological and structural brain development. We examined the effect of REM sleep deprivation during the critical period for visual development on the development of two calcium‐binding proteins that are associated with developmental synaptic plasticity and are found in the lateral geniculate nucleus (LGN) and visual cortex. In this study, REM sleep deprivation was carried out utilizing a computer‐controlled, cage‐shaking apparatus that successfully suppressed REM sleep. Body weight data suggested that this method of REM sleep deprivation produced less stress than the classical multiple‐platform‐over‐water method. In REM sleep‐deprived animals with normal binocular vision, the number of parvalbumin‐immunoreactive (PV) neurons in LGN was found to be lower compared with control animals but was not affected in visual cortex. The pattern of calbindin‐immunoreactivity (CaB) was unchanged at either site after REM sleep deprivation. Parvalbumin‐immunoreactivity develops later than calbindin‐immunoreactivity in the LGN, and the REM sleep deprivation that we applied from postnatal day 42–49 delayed this essential step in the development of the kitten’s visual system. These data suggest that in early postnatal brain development, REM sleep facilitates the usual time course of the expression of PV‐immunoreactivity in LGN neurons.