Biomedical subjects

Stian Lydersen

Publications and source records attributed to Stian Lydersen.

24 records · Page 2Linked to original sources

PubMed2004

Parameters describing motion in carotid artery plaques from ultrasound examination: A reproducibility study.

We have previously developed a method for quantifying motion in carotid artery plaques from sequences of ultrasound (US) radiofrequency images. Here, we examine the intraoperator reproducibility of the results. Five independent recordings were made on each of six symptomatic and six asymptomatic patients, and processed off-line into 29 motion parameters, representing motion amplitude, stretch/compression and shear motion. For the statistical analysis, we used a linear mixed model and investigated the parameters for contributions from individual patients, contributions from recordings on each patient and contributions from heart cycles within each recording. The model was valid for seven parameters calculated over the entire heart cycle (four calculated over the systole only), which all showed good reproducibility (intraclass coefficient for variance over all patients rho(alpha) >/= 0.4). Averaging three recordings of two heart cycles each gives acceptable accuracy (normalised variance of patient means lambda < 0.3). This acquisition scheme is reasonable in a clinical situation.

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PubMed2004

Radiosurgery versus conventional surgery for dermatochalasis.

PURPOSE: To compare hemorrhage and wound healing after radiosurgery and conventional surgery for dermatochalasis. METHODS: We performed a prospective study of 13 patients with dermatochalasis who underwent radiosurgery in one upper eyelid and conventional surgery with scalpel and scissors in the contralateral eyelid. Hemorrhage and wounds were evaluated after surgery the same day, 1 week later, and 3 months after surgery by a masked observer. Hemorrhage was evaluated on a scale from 0 (no hemorrhage) to 4; wounds were evaluated by use of Hollander score, from 0 (poorest outcome) to 6 (best outcome). RESULTS: We found a tendency toward better wound healing and a higher Hollander score at 1 week after radiosurgery (p=0.014) and no significant differences in wound healing and hemorrhage between radiosurgery and the conventional technique. CONCLUSIONS: Both radiosurgery and conventional surgery for dermatochalasis showed good results at the 3-month follow-up.

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PubMed2004

Acute stroke unit care combined with early supported discharge. Long-term effects on quality of life. A randomized controlled trial.

OBJECTIVES: The aim of the present trial was to compare the effects of an extended stroke unit service (ESUS) with the effects of an ordinary stroke unit service (OSUS) on long-term quality of life (QoL). DESIGN: One year follow-up of a randomized controlled trial with 320 acute stroke patients allocated either to OSUS (160 patients) or ESUS (160 patients) with early supported discharge and follow-up by a mobile team. The intervention was a mobile team and close co-operation with the primary health care service. All assessments were blinded. MAIN OUTCOME MEASURE: Primary outcome of QoL in this paper was measured by the Nottingham Health Profile (NHP) at 52 weeks. Secondary outcomes measured at 52 weeks were differences between the groups measured by the Frenchay Activity Index, Montgomery-Asberg Depression Scale, Mini-Mental State Score and the Caregivers Strain Index. RESULTS: The ESUS group had a significantly better QoL (mean score 78.9) assessed by global NHP after one year than the OSUS group (mean score 75.2) (p =0.048). There were no significant differences between the groups in the secondary outcomes, but a trend in favour of ESUS. Caregivers Strain Index showed a mean score of 23.3 in the ESUS group and 22.6 in the OSUS group (p=0.089). CONCLUSION: It seems that stroke unit treatment combined with early supported discharge in addition to reducing the length of hospital stay can improve long-term QoL. However, similar trials are necessary to confirm the benefit of this type of service.

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PubMed2003

Power comparison of two-sided exact tests for association in 2 x 2 contingency tables using standard, mid p and randomized test versions.

Exact Pearson's chi square, likelihood ratio (LR), and Fisher's tests are obtained from the conditional distribution of its test statistic, given the row and column sums of the contingency table. The power and obtained significance level of the standard, mid p, and randomized versions of these tests are compared for two-sided tests in 2 x 2 tables, using binomial and multinomial sampling. The mid p type I error probabilities seldom exceed the nominal significance level. The mid p and randomized test versions have approximately the same power, and higher power than the standard test version. The power of the Pearson's chi square, LR and Fisher's test differ, and they differ in approximately the same way for standard, mid p and randomized test versions for any given set of parameters. There is no general ranking between the three tests. In many cases, Pearson's chi square and Fisher's tests have almost equal power, and higher power than LR. In a few cases, perhaps characterized by poorly balanced designs, LR performs best. Fisher's test seems to be slightly more robust even if the design is poor.

Binomial Distribution↗

PubMed2003

Stroke unit care combined with early supported discharge: long-term follow-up of a randomized controlled trial.

BACKGROUND AND PURPOSE: Early supported discharge from a stroke unit reduces the length of hospital stay. Evidence of a benefit for the patients is still unknown. The aim of this trial was to evaluate the long-term effects of an extended stroke unit service (ESUS), characterized by early supported discharge. The short-term effects were published previously. METHODS: We performed a randomized controlled trial in which 320 acute stroke patients were allocated to either ordinary stroke unit service (OSUS) (160 patients) or stroke unit care with early supported discharge (160 patients). The ESUS consists of a mobile team that coordinates early supported discharge and further rehabilitation. Primary outcome was the proportion of patients who were independent as assessed by modified Rankin Scale (RS) (RS < or =2=global independence). Secondary outcomes measured at 52 weeks were performance on the Barthel Index (BI) (BI > or =95=independent in activities of daily living), differences in final residence, and analyses to identify patients who benefited most from an early supported discharge service. All assessments were blinded. RESULTS: We found that 56.3% of the patients in the ESUS versus 45.0% in the OSUS were independent (RS < or =2) (P=0.045). The number needed to treat to achieve 1 independent patient in ESUS versus OSUS was 9. The odds ratio for independence was 1.56 (95% CI, 1.01 to 2.44). There were no significant differences in BI score and final residence. Patients with moderate to severe stroke benefited most from the ESUS. CONCLUSIONS: Stroke service based on treatment in a stroke unit combined with early supported discharge appears to improve the long-term clinical outcome compared with ordinary stroke unit care. Patients with moderate to severe stroke benefit most.

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PubMed2002

Prevalence of refractive errors in young and middle-aged adults in Norway.

PURPOSE: To determine the prevalence of refractive errors in the young and middle-aged adult population in Norway. METHODS: Refractive errors were measured in a population-based sample of young (20-25 years) and middle-aged (40-45 years) adults participating in the Helseundersøkelse i Nord Trøndelag (HUNT) Health Study, conducted in the County of Nord-Trøndelag in Norway. RESULTS: A total of 3137 persons (1248 young and 1889 middle-aged adults) with corrected visual acuity > or = 0.5 (in either eye) were included in the study. The prevalence of myopia was 35.0% in the young adult group and 30.3% in the middle-aged group. Myopia was significantly higher in women aged 20-25 years (36.4%) than in men aged 40-45 years (28.1%). Prevalence of hyperopia increased with age from 13.2% (20-25 years) to 17.4% (40-45 years). The highest rate of hyperopia (20.1%) was encountered in middle-aged women. CONCLUSION: The results show a slightly higher prevalence of myopia in the general population of Norway than previously estimated.

Adult↗