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Biomedical subjects

P Laake

Publications and source records attributed to P Laake.

7 recordsLinked to original sources
PubMed1992

Hemodynamic evaluation of the CarboMedics prosthetic heart valve in the aortic position: comparison of noninvasive and invasive techniques.

Seventy-three patients with a CarboMedics aortic bileaflet valve prosthesis were examined by Doppler ultrasonography, and 27 of them were also assessed by transseptal catheterization. The ultrasonic mean systolic gradient was 17.1 +/- 5.6 mm Hg for valve size 19 mm, falling gradually with increasing valve size to 6.8 +/- 2.5 mm Hg for size 27 mm. The catheter mean systolic gradient was consistently smaller than the ultrasonic gradient (4.3 +/- 4.8 mm Hg), but Tobit regression analysis showed a significant association between the two methods. In all patients both methods revealed negligible to small amounts of retrograde leakage, which is assumed to be a normal finding for this valve. The effective flow areas of the valves calculated from the ultrasonic data were similar to the in vitro calculated flow areas. The hemodynamic potential of this valve is therefore completely utilized in vivo. The effective orifice area corrected for body surface area increased with increasing valve size, which demonstrates a moderate valve-patient mismatch.

Adult↗
PubMed1991

Sex-specific trends in mortality for the aging population in Norway: a model with age, period, and cohort effects.

During the last few decades, the citizens of most western countries have experienced an increased expectation of life. The rate of this change differs for males and females. We evaluated reasons for this pattern, using a Poisson model, with age, period, and cohort effects applied to vital statistics data from the Central Bureau of Statistics of Norway. The data comprised the total Norwegian population aged 45 to 104 years who died in the period from 1966 until 1986. Differential changes in life expectancy for the elderly are explained by differences in sex-specific cohort effects. We also observed an extra-Poisson variation, or overdispersion, in the distribution for females.

Age Factors↗
PubMed1989

Electroencephalography, visual evoked potentials, and cerebral CAT-scan as diagnostic tools in senile dementia of Alzheimer type.

The usefulness of a cerebral computed tomogram (CAT-scan), an electro-encephalogram (EEG), and flash visual evoked responses (FVER) as diagnostic tools in dementia was studied in 36 mentally impaired and 32 unimpaired persons aged 75 yr and above, who were recruited from a random sample of elderly people living at home. The clinical diagnosis of dementia was made after a full psychogeriatric assessment supplemented by a follow-up 18 mo later. When the measures of cortical atrophy from a cerebral CAT-scan, the presence/absence of diffuse slow activity on a standard EEG, and FVER P200 and FVER P100 latencies were introduced in a logistic regression model, the clinical diagnoses being the dependent variable, an effective prediction of senile dementia of Alzheimer type (SDAT) was obtained (sensitivity 93%, specificity 86%, misclassification rate 12%). We conclude that the use of FVER, an EEG, and a cerebral CAT-scan may facilitate the diagnosis of senile dementia of Alzheimer type.

Aged↗
PubMed1988

Efficacy of short mental tests in the detection of mental impairment in old age.

The usefulness, inter-rater reliability, and validity of six mental tests, the MMS, the GMS, the MSQ, the VRT, the OLT, and the DCT were studied in 81 patients over the age of 75 years. The patients were classified as being mentally impaired or unimpaired by psychogeriatric assessment. All tests had high reliability. The MMS, GMS, MSQ, and OLT were the most feasible and useful. The tests were validated by logistic regression analysis and the most efficient were the MMS, GMS, and OLT. Improvement was achieved when two or all three tests were used simultaneously. The three tests seem to be suitable tools for the detection of mental failure in patients of old age.

Aged↗
PubMed1987

A model for physician utilization within 2 weeks. Analysis of Norwegian data.

This study considers Norwegian physician utilization to be determined by need, enabling, and predisposing variables. The main issue is whether factors aside from need create any differences in physician use. In this article, we analyze the number of contacts with physicians in a period of 2 weeks. We consider models for a first contact and follow-up contacts with physicians. Physician utilization in the 2-week period is studied by logistic regression models for a person's first contact and follow-up contacts with physicians. The number of follow-up contacts is analyzed by a simple regression model. Because the total number of physician contacts is the sum of a first visit and the number of follow-up contacts, we are able to study the effect of the need, enabling, and predisposing variables related to the total number of contacts with physicians.

Adolescent↗
PubMed1985

On the problem of measuring the distance between distribution functions: analysis of hospitalization versus mortality.

The relationship between hospitalization, as a measure of morbidity, and mortality is examined. The difference between age at hospitalization in a general medical department and age at death in Oslo, Norway, is studied. The problem is transferred to the one of examining the difference between two cumulative distribution functions F and G. For this purpose, a quantile distance function based on the inverses of the distribution functions is applied. We give the natural estimate of the quantile distance function, and some asymptotic properties of the corresponding empirical process. For the particular situation where one of the distribution functions is known, a confidence band for the quantile distance function is derived. Applying these results, we show that there are reasons to believe that age at hospitalization and age at death are equally distributed, apart from a constant shift.

Adult↗