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O Ekeberg

Publications and source records attributed to O Ekeberg.

At least 19 recordsLinked to original sources
PubMed2002

A Bayesian attractor network with incremental learning.

A realtime online learning system with capacity limits needs to gradually forget old information in order to avoid catastrophic forgetting. This can be achieved by allowing new information to overwrite old, as in a so-called palimpsest memory. This paper describes an incremental learning rule based on the Bayesian confidence propagation neural network that has palimpsest properties when employed in an attractor neural network. The network does not suffer from catastrophic forgetting, has a capacity dependent on the learning time constant and exhibits faster convergence for newer patterns.

Bayes Theorem↗
PubMed2001

Suicidal ideation among medical students and young physicians: a nationwide and prospective study of prevalence and predictors.

BACKGROUND: Despite an increased risk of suicide among physicians we lack studies on prevalence and predictors of suicidal ideation among medical students and young doctors. METHOD: A prospective study of Norwegian medical students (n=522) re-examined after the first postgraduate year, comprising suicidal thoughts and attempts, perceived study stress, job stress, and personality. RESULTS: The previous year prevalence of suicidal thoughts was 14% at both points of time. The lifetime prevalence was 43%, while 8% had planned suicide, and 1.4% had attempted suicide. Suicidal ideation in medical school was predicted by lack of control, personality trait, single marital status, negative life events and mental distress (anxiety and depression). In the first postgraduate year, mental distress was the most important predictor, but before controlling for this variable, job stress, vulnerability (neuroticism), single status, and less working hours were independent predictors. Prospectively, suicidal thoughts and vulnerability as student predicted postgraduate suicidal ideation. CONCLUSIONS: The level of suicidal thoughts was high, but the level of attempts was low. CLINICAL IMPLICATIONS: Preventive efforts should be directed both at the students' abilities to cope with stress and at mental health services for young doctors. LIMITATIONS OF STUDY: The lower response rate at follow-up (57%) may reduce external validity.

Adaptation, Psychological↗
PubMed2001

Adoption of new health care services in Norway (1993-1997): specialists' self-assessment according to national criteria for priority setting.

OBJECTIVES: To identify health care services adopted in Norway in the period 1993-1997, and examine them according to proposed national guidelines for priority setting. These guidelines define core services. DESIGN: Two-stage self-administered questionnaire. SETTING: The Norwegian public healthcare system. SUBJECTS: Presidents of all relevant specialist and sub-specialist associations in the Norwegian Medical Association (n=56). OUTCOME MEASURES: Number of adopted services satisfying the priority criteria of core services, according to physician's self-assessment. Number and type of interventions suited for the priority-setting criteria. RESULTS: Thirty-two percent of new technologies satisfied the definition of core services according to specialists' own assessment. Of the 88 responses analysed for the second stage of our survey, fifteen answers (17%) indicated lack of applicability of the priority setting criteria. Loss of applicability was related to diagnostic and procedure-related technologies. CONCLUSIONS: Less than one-half of the assessed technologies adopted in Norway in the period 1993-1997 satisfy proposed national criteria for priority setting. The guidelines are applicable for most interventions, but fail in most evaluations of diagnostic and procedure-related improvements. Independent and systematic evaluations of new technologies are needed within the context of priority setting.

Attitude of Health Personnel↗
PubMed2001

Suicide rates from 1960 to 1989 in Norwegian physicians compared with other educational groups.

The aim of the present study is to compare suicide rates between 1960 and 1989 for Norwegian physicians with corresponding rates for other Norwegians with and without university education, by age, gender, and five-year period, based on death certificates for all Norwegians who died in the period 1960-1989. There were 82 registered physician suicides, of which 9 were female, 265 suicides by persons with other university education, and 11,165 by persons with no university education. Suicide rate is measured in number of deaths per 100,000 person years. Crude suicide rates were 47.7 (95% CI 37.7-60.4) for male physicians, 20.1 (17.7-22.9) for other male university graduates, and 22.7 (22.2-23.2) for men with no university education. The corresponding figures for females were 32.3 (15.8-63.7), 13.0 (8.4-19.8) and 7.7 (7.5-8.0). Both for males and females, suicide rates, controlled for age and period, were significantly higher for physicians than for persons with other or no university education. Poisson modelling showed that the risk of suicide for male physicians has the same age pattern as for other males with higher education. In 1985-89 the suicide rate for male physicians increased nearly linearly from about 35 at the age 35-40 to about 100 at the age 75-79, which was almost three times higher than for the other male university graduates. For the age group 50-54 the estimated rate increases from about 50 in 1960-64 to about 90 in 1985-89. For the female physicians, the low number of cases prevents reliable estimation of trends. For male physicians, the trend from 1960 to 1989 is increasing. The estimated risk for a single physician to commit suicide was almost 5 times that of a married or co-habitant colleague. For 52% of the male and 85% of the female physicians the suicide method was poisoning. This is about twice the rates in the general population.

Adult↗
PubMed2001

Factors in medical school that predict postgraduate mental health problems in need of treatment. A nationwide and longitudinal study.

CONTEXT: Physicians show an increased prevalence of mental health problems, the first postgraduate years being particularly stressful. OBJECTIVES: To study the prevalence of mental health problems during the fourth postgraduate year, and to investigate whether it is already possible to predict such problems at medical school. SUBJECTS: A cohort of medical students (n=396) from all Norwegian universities, who were approached in their graduating semester (baseline) and in their fourth postgraduate year. METHODS: A nationwide and longitudinal postal questionnaire survey, including measures of perceived mental health problems in need of treatment, personality, perceived stress and skills, and ways of coping. Data were analysed using logistic regression. RESULTS: Mental health problems in need of treatment during the fourth postgraduate year were reported by 17.2% (n=66), with no gender difference, possibly because of a higher prevalence among the men compared with the general population. A majority had not sought help. Univariate medical school predictors of mental health problems included: previous mental health problems; not being married/cohabitant; the personality traits 'vulnerability' (or neuroticism) and 'reality weakness'; perceived medical school stress, and lack of perceived diagnostic skills. In addition, the coping variables avoidance, blamed self and wishful thinking were univariate predictors. Multivariate analysis identified the following adjusted predictors: previous mental health problems; 'intensity' (extraversion); perceived medical school stress, and wishful thinking. Medical school variables were inadequate for predicting which individual students would experience postgraduate mental health deterioration. However, the perceived medical school stress instrument may be used for selecting a subgroup of students suitable for group-oriented interventions.

Adaptation, Psychological↗
PubMed2001

Toward an integrative model of suicide attempt: a cognitive psychological approach.

Applying a cognitive approach, the purpose of the present study was to expand previous research on stress-vulnerability models of depression and problem-solving deficits, as it relates to suicide attempt. Structural equation modelling, involving latent variables, was used to evaluate (a) whether low self-esteem, a low sense of self-efficacy, loneliness, and divorce constituted vulnerability factors for the development of depression; (b) whether hopelessness and suicidal ideation mediated the relationship between depression and suicide attempt; and (c) whether problem-solving deficits mediated the relationship between the vulnerability factors and suicide attempt, separate from depression/hopelessness. A total of 123 individuals, aged 18-75 years, participated in the study (72 suicide attempters and 51 psychiatric outpatients with no history of suicidal behavior). The results indicated a two path model of suicide attempt. The first path began with low self-esteem, loneliness, and separation or divorce, which advanced to depression, and was further mediated by hopelessness and suicidal ideation which led to suicide attempt. The second path developed from low self-esteem and a low sense of self-efficacy and advanced to suicide attempt, mediated by a negative appraisal of one's own problem-solving capacity, and poor interpersonal problem-solving skills. The importance of addressing both depression/hopelessness, and problem-solving deficits when working with suicide attempters is noted.

Adolescent↗
PubMed2000

Adolescents hospitalised with deliberate self-harm: the significance of an intention to die.

All suicide attempters admitted to medical wards in the greater Oslo area, (n = 91) aged 13-19 years, were dichotomised on the basis of one item in the Motives for Parasuicide Questionnaire (MPQ) and one item in the Suicide Intent Scale (SIS): if the intent was to die (n = 57), or not (n = 34). The two groups were compared regarding the attempt, mental health problems, and psychosocial risk factors. The attempt of adolescents with an intent to die were more serious, rated with SIS (15.7 vs. 5.7, p < 0.001), with Risk Rescue Rating (p = 0.003) or rated medically (p < 0.05). They were clinically more often depressed (61% vs. 32%, p < 0.01), felt more hopeless (Hopelessness Scale) (10.8 vs. 8.2, p < 0.05), were less disruptive (11% vs. 32%, p < 0.05) and less often abused substances (0 vs. 12%, p < 0.05). Both groups were equally burdened with other factors. Differentiation on the basis of suicidal intent delineated two groups, both with considerable psychosocial problems. Those with suicide intent had more internalising problems including depression, while those with other intents showed more externalising behaviour. The need for help in the group with no intent to die may be underestimated.

Adolescent↗
PubMed2000

The prevalence of suicidal ideation and suicidal attempts among Norwegian physicians. Results from a cross-sectional survey of a nationwide sample.

Physicians have a higher suicide rate than the general population or other academics. Little is known about the reasons for this. Analysing risk factors may be a valuable way of identifying reasons for the high suicide rate among physicians, thereby leading to preventive efforts. The present study is one of the first papers on suicidal thoughts and attempts among physicians. A questionnaire about suicidal thoughts (developed by E.S. Paykel) was completed by 1,063 of 1,476 active Norwegian physicians (72%). Lifetime prevalence ranged from 51.1% for feelings that life was not worth living to 1.6% for a suicide attempt. Risk factors were being female, living alone, and depression. Suicidal thoughts, however, were hardly attributed to working conditions. A high rate of suicide and a low rate of suicidal attempts support the hypothesis that physicians do not 'cry for help,' but are inclined to act out their suicidal impulses.

Adult↗
PubMed2000

The relationship between cognitions and panic attack intensity.

OBJECTIVE: To investigate the relationship between panic attack intensity, catastrophic belief and cognitions. METHOD: Data from 540 panic diaries were collected from 42 patients with panic disorder with agoraphobia. RESULTS: When we controlled for individual variation, effects of treatment and number of symptoms, catastrophic belief contributed significantly to more intense panic attacks (r2 change = 0.10, P<0.0001). There were no significant differences in panic attack intensity between primary and secondary cognitions. CONCLUSION: Our results indicate that catastrophic belief is a reliable predictor of panic attack intensity.

Adult↗
PubMed2000

The impact of job stress and working conditions on mental health problems among junior house officers. A nationwide Norwegian prospective cohort study.

CONTEXT: Previous studies have shown that physicians have an increased risk of mental health problems such as depression, suicide and substance abuse. OBJECTIVES: To study the prevalence of mental health problems during the first postgraduate year, and to investigate whether work-related factors in hospital are linked to these, when we control for gender, previous mental health problems, personality traits, stress in medical school and other possible predictors. DESIGN: Nationwide and prospective postal questionnaire survey. SETTING: University of Oslo. SUBJECTS: Medical students who answered questionnaires in their graduating semester, and 1 year later when they were junior house officers (n=371). RESULTS: Mental health problems (needing treatment) during internship were reported by 11%, with no gender difference. Adjusted predictors of mental health problems were: previous mental health problems, (odds ratio (OR)=5.1, 95% confidence interval (CI) 1.7 to 15.8); being married/cohabitant (OR=0.2, CI 0.1 to 0.7); the personality trait 'vulnerability' (OR=1.5, CI 1.1 to 2.0); negative life events during internship (OR=2.1, CI 1.2 to 3.5), and job stress as house officer (OR=1.05, CI 1.01 to 1.10). The job stress factor of emotional pressure/demands from patients was most important. Perceived study stress and lack of skills at the end of medical school were univariately related to mental health problems in internship, but not when other variables were adjusted. Gender, weekly working hours and lack of sleep were not linked to having problems. CONCLUSION: Job stress is related to mental health problems among young doctors, even when the variables of previous mental health problems and personality traits are controlled for. More support during internship is needed.

Adult↗
PubMed2000

Young suicide attempters: a comparison between a clinical and an epidemiological sample.

OBJECTIVE: To compare risk factors for self-harm in 2 groups: hospitalized adolescents who had attempted suicide and adolescents reporting suicide attempts in a community survey. METHOD: All suicide attempters aged 13 to 19 years admitted to medical wards (n = 91) in a region of Norway were assessed and interviewed. Risk factors were identified by comparisons with a general population sample participating in a questionnaire study in the same community (n = 1,736). In this population sample, a separate analysis of risk factors for reporting deliberate self-harm (n = 141) was performed, applying bivariate and multivariate logistic regression models. RESULTS: Adjusted risk factors for suicide attempts in hospitalized adolescents were depression (odds ratio [OR] = 4.7), disruptive disorders (OR = 9.4), low self-worth (OR = 1.3), infrequent support from parents (OR = 3.3) or peers (OR = 3.3), parents' excessive drinking (OR = 4.3), and low socioeconomic status (OR = 2.4). For adolescents who self-reported self-harm, depression (OR = 3.1) and loneliness (OR = 1.13) were significant adjusted risk factors (p < .001). Low self-worth, low socioeconomic status, and little support from parents or peers characterized hospitalized suicidal adolescents compared with those who were not hospitalized. CONCLUSIONS: The risk factors were more powerful for hospitalized than for nonhospitalized adolescents. Prevention efforts should target the same factors for both groups, at a population level for nonhospitalized adolescents and at an individual level for hospitalized adolescents, with a focus on depression, low self-esteem, and family communication.

Adolescent↗
PubMed2000

Precision grip force dynamics: a system identification approach.

A linear model of the dynamics of the human precision grip is presented. The transfer function is identified as representing the peripheral motor subsystem, from the motoneuron pool to the final production of a grip force between the tip of the index finger and the thumb. The transfer function captures the limiting isometric muscle dynamics that, e.g., cortical motor areas have to act through. When identifying the transfer function we introduce a novel technique, common subsystem identification. This characterizes a specific subsystem in a complex biomechanical system. This technique requires data from two functionally different experiments that both involve the subsystem of interest. Two transfer functions, one for each experiment, are then estimated using a linear black box technique. The common mathematical factors, represented by poles and zeros, are used to form a new transfer function. It is concluded that this transfer function represents the common biological subsystem involved in both experiments. Here, we use one active and one reactive isometric grip force experiment to capture the subsystem of interest, i.e., the motoneuron pool, motor units, muscles, tendons and fingertip tissue. The characteristics of the dynamics are in agreement with previously published experiments on human neuro-muscular systems. The model, H(s) = 280/(s2 + 22s + 280), is well suited for the representation of a force producing end-effector in simulations including a control system with sensory feedback.

Adult↗
PubMed2000

Suicidal behavior in the municipality of Baerum, Norway: a 12-year prospective study of parasuicide and suicide.

The present 12-year (1984-1995) surveillance study includes all hospitalized parasuicide patients (n = 1,031) as well as all suicides (n = 161) in the municipality of Baerum, a suburb of Oslo. The parasuicide rate decreased from 170 per 100,000 in 1984 to 79 per 100,000 in 1995 (53.5%). The parasuicide rates were lower than those in several comparable studies. Rates were higher for divorced females and separated males compared to married and other marital states, and the pattern of relative risk of parasuicide with respect to marital status was stable. Unemployment and substance abuse were positively correlated with parasuicidal behavior for both males and females. Approximately 33% reported one or more previous parasuicidal acts, and 21% repeated the parasuicide during the observation period. Ninety-four percent used self-poisoning as parasuicide method. A total of 2.4% of the parasuiciders committed suicide during the observation period. The mean annual suicide rate in Baerum was 19.0 per 100,000 compared to the national average of 14.7. The results support the notion of parasuicide and suicide being two different but overlapping populations. The implementation of a follow-up system for parasuiciders may have contributed to the reduced parasuicide rate during the study period.

Adolescent↗
PubMed1999

[Patients' quality of life after transplantation--what do we know?].

The number of organ transplantations has increased considerably over the last 30 years. The aim of organ transplantation is to increase the life expectancy of the patients and to give them a meaningful life with better quality. Transplantation of kidney, heart, lung, liver and bone marrow leads to considerably higher health-related quality of life. If the somatic adverse reactions are controlled, quality of life in transplant recipients is reported to be almost as good as in the general population.

Humans↗
PubMed1999

Simulations of neuromuscular control in lamprey swimming.

The neuronal generation of vertebrate locomotion has been extensively studied in the lamprey. Models at different levels of abstraction are being used to describe this system, from abstract nonlinear oscillators to interconnected model neurons comprising multiple compartments and a Hodgkin-Huxley representation of the most relevant ion channels. To study the role of sensory feedback by simulation, it eventually also becomes necessary to incorporate the mechanical movements in the models. By using simplifying models of muscle activation, body mechanics, counteracting water forces, and sensory feedback through stretch receptors and vestibular organs, we have been able to close the feedback loop to enable studies of the interaction between the neuronal and the mechanical systems. The neuromechanical simulations reveal that the currently known network is sufficient for generating a whole repertoire of swimming patterns. Swimming at different speeds and with different wavelengths, together with the performance of lateral turns can all be achieved by simply varying the brainstem input. The neuronal mechanisms behind pitch and roll manoeuvres are less clear. We have put forward a 'crossed-oscillators' hypothesis where partly separate dorsal and ventral circuits are postulated. Neuromechanical simulations of this system show that it is also capable of generating realistic pitch turns and rolls, and that vestibular signals can stabilize the posture during swimming.

Animals↗
PubMed1999

The Illness Attitude Scales in chest pain patients: a study of psychometric properties.

The main aim of the study was to assess the factorial structure of the Illness Attitude Scales (IAS). The study population comprised 199 patients referred to cardiological out-patient investigation because of chest pain. The factor analysis revealed three factors of the IAS. Accordingly, we found three subscales, interpreted as health anxiety (HA), illness behavior (IB), and health habits (HH). The internal consistency of the subscales, measured by Cronbach's alpha coefficient, were 0.92, 0.80, and 0.49, respectively. The HA and IB scores were significantly intercorrelated (r = 0.39, p < 0.001), but HH was not significantly correlated with either HA or IB. The HA and IB subscales discriminated between patients with and without panic disorder. The results support previous findings, namely that the IAS comprise two subscales with psychometrically sound properties. Correlational analysis indicated validity of the two subscales. Further studies are needed to confirm the validity.

Attitude to Health↗
PubMed1999

Reduced health-related quality of life among Hodgkin's disease survivors: a comparative study with general population norms.

BACKGROUND: Late complications after curative treatment of Hodgkin's disease are of special relevance because most of the cured are young adults. The aims of the present study were: (1) to compare health-related quality of life (HRQOL) in Hodgkin's disease (HD) survivors with normative data from the general Norwegian population and (2) to examine the relations between disease/treatment characteristics and HRQOL in the HD survivors. PATIENTS AND METHODS: 459 HD survivors aged 19-74 years (mean 44.0, SD 11.8) treated at the Norwegian Radium Hospital 1971-1991 were approached in 1994 and compared to norms from 2214 subjects approached in 1996. The norms are representative of the general Norwegian population. HRQOL was assessed by the Short Form 36 (SF-36), which measures HRQOL in eight separate scales (0 = worst health state, 100 = best health state). RESULTS: The HD survivors had lower scores than the normal controls on all scales after adjustment for age, gender and educational levels. Statistically significant differences (P < 0.01) were found in general health (10.4), physical functioning (6.1), role limitations (physical, 9.3), physical functioning (3.6) and in vitality (4.7). Patients with disease stage IB-IIB had the lowest scores on all scales. The differences in relation to stage/substage reached statistical significance (P < 0.01) in physical functioning and in role limitations (physical). Time since diagnosis, types of primary treatment or having relapsed were not associated with statistically significant differences in HRQOL. CONCLUSION: Long-term HD survivors have poorer HRQOL, primarily in physical health, than the general Norwegian population.

Adult↗