Jörn Schulz

Development of excessive daytime sleepiness in early Parkinson disease

Objective: To examine the frequency, development, and risk factors of excessive daytime sleepiness (EDS) in a cohort of originally drug-naive patients with incident Parkinson disease (PD) during the first 5 years after diagnosis. Methods: One hundred fifty-three drug-naive patients with early PD derived from a population-based incident cohort and 169 control participants were assessed for EDS and reevaluated after 1, 3, and 5 years on medication. EDS was diagnosed according to the Epworth Sleepiness Scale. Cutoff score above 10 was applied. Generalized estimating equation models for correlated data were used to examine associated and risk factors for EDS. Results: Patients reported EDS more often than control participants at the time of diagnosis and during follow-up. The frequency of EDS in PD increased from 11.8% at baseline to 23.4% after 5 years. Associated factors were male sex, the use of dopamine agonists, and higher Montgomery-Åsberg Depression Rating Scale and Unified Parkinsons Disease Rating Scale–activities of daily living scores. Main risk factor for developing EDS was an increased Epworth Sleepiness Scale score at baseline. Conclusion: EDS is more frequent in PD even before treatment initiation compared with control participants and increases in occurrence with disease progression. The main risk factor for developing EDS with time is an early predisposition for sleepiness. In addition, the use of dopamine agonists was associated with the development of EDS. These findings necessitate caution in patients with PD and early increased sleep propensity and when using dopamine agonists.

Analysis of Rotational Deformations From Directional Data

This article discusses a novel framework to analyze rotational deformations of real three-dimensional objects. The rotational deformations such as twisting or bending have been observed as the major variation in some medical applications, where the features of the deformed three-dimensional objects are directional data. We propose modeling and estimation of the global deformations in terms of generalized rotations of directions. The proposed method can be cast as a generalized small circle fitting on the unit sphere. We also discuss the estimation of descriptors for more complex deformations composed of two simple deformations. The proposed method can be used for a number of different three-dimensional object models. Two analyses of three-dimensional object data are presented in detail: one using skeletal representations in medical image analysis and the other from biomechanical gait analysis of the knee joint. Supplementary materials for this article are available online.

Judicious use of oxytocin augmentation for the management of prolonged labor

A protocol including judicious use of oxytocin augmentation was investigated to determine whether it would change how oxytocin was used and eventually influence labor and fetal outcomes.

Normal Newborn Heart Rate in the First Five Minutes of Life Assessed by Dry-Electrode Electrocardiography.

Background: There is limited evidence regarding the heart rate (HR) during the first minutes of life. Nonetheless, resuscitative actions within the first minute are partly guided by different HR levels. The advent of an electrocardiographic (ECG) HR sensor with early HR detection has provided the opportunity to study changes immediately following delivery. Objective: The objectives were to determine immediately following delivery: (i) the time to achievement of reliable ECG signals using dry electrodes, (ii) changes in HR, and (iii) the influence of the onset of breathing and cord clamping on the HR. Methods: Healthy term neonates were randomly included between July and October 2013. The HR was recorded by the ECG sensor, placed over the abdomen immediately after birth. Results: Fifty-five newborns were included. The median time from birth to placement of the HR sensor was 3 s (quartiles: 2 and 5), and the median time to the start of breathing was 6 s (quartiles: 2 and 15). The HR was around 120 beats/min (bpm) in the first seconds of life. As determined via breakpoint analysis, the HR increased by 1 beat in the first 40 s to 149 ± 33 bpm, followed by a moderate increase until 130 s and stabilization thereafter. After the onset of breathing, the HR decreased for 10 s and then increased. Minimal HR changes were observed after cord clamping. Conclusion: A dry-electrode ECG sensor detected reliable ECG signals almost immediately after birth. The normal HR increased significantly in spontaneously breathing infants during the first minute, influenced by the onset of breathing. Delayed cord clamping had a minimal impact on the HR, likely reflecting an earlier onset of breathing.

Non-linear Hypothesis Testing of Geometric Object Properties of Shapes Applied to Hippocampi

This paper presents a novel method to test mean differences of geometric object properties (GOPs). The method is designed for data whose representations include both Euclidean and non-Euclidean elements. It is based on advanced statistical analysis methods such as backward means on spheres. We develop a suitable permutation test to find global and simultaneously individual morphological differences between two populations based on the GOPs. To demonstrate the sensitivity of the method, an analysis exploring differences between hippocampi of first-episode schizophrenics and controls is presented. Each hippocampus is represented by a discrete skeletal representation (s-rep). We investigate important model properties using the statistics of populations. These properties are highlighted by the s-rep model that allows accurate capture of the object interior and boundary while, by design, being suitable for statistical analysis of populations of objects. By supporting non-Euclidean GOPs such as direction vectors, the proposed hypothesis test is novel in the study of morphological shape differences. Suitable difference measures are proposed for each GOP. Both global and simultaneous GOP analyses showed statistically significant differences between the first-episode schizophrenics and controls.

The relation between given volume and heart rate during newborn resuscitation

BACKGROUND During delivery room resuscitation of depressed newborns, provision of appropriate tidal volume (TV) with establishment of functional residual capacity (FRC) is essential for circulatory recovery. Effective positive pressure ventilation (PPV) is associated with a rapid increase in heart rate (HR). The relationship between delivery of TV and HR responses remains unclear. OBJECTIVES The study objectives were to determine (1) the relationship between a given TV during initial PPV and HR responses of depressed newborns, and (2) the optimal delivered TV associated with a rapid increase in HR. METHODS In a Tanzanian rural hospital, ventilation and ECG signals were recorded during neonatal resuscitation and stored in Neonatal Resuscitation Monitors. Resuscitators without positive end-expiratory pressure were used for PPV. No oxygen was used. Perinatal events were observed and recorded by research assistants. RESULTS 215 newborns of gestational age 37.3±1.9 weeks and birth weight 3115±579g were included. There was a non-linear relationship between delivered TV and HR increase. TV of 9.3ml/kg produced the largest increase in HR during PPV. Frequent interruptions of PPV sequences to provide stimulation/suctioning occurred in all cases and were associated with further HR increases, especially for newborns with initial HR<100 beats/minute. CONCLUSIONS There was a consistent positive relationship between HR increase and delivered TV. The unanticipated finding of a further increase in HR with PPV pauses to provide stimulation/suctioning suggests that most newborns were in primary rather than secondary apnea.

Non-Euclidean classification of medically imaged objects via s-reps ☆

Classifying medically imaged objects, e.g., into diseased and normal classes, has been one of the important goals in medical imaging. We propose a novel classification scheme that uses a skeletal representation to provide rich non-Euclidean geometric object properties. Our statistical method combines distance weighted discrimination (DWD) with a carefully chosen Euclideanization which takes full advantage of the geometry of the manifold on which these non-Euclidean geometric object properties (GOPs) live. Our method is evaluated via the task of classifying 3D hippocampi between schizophrenics and healthy controls. We address three central questions. 1) Does adding shape features increase discriminative power over the more standard classification based only on global volume? 2) If so, does our skeletal representation provide greater discriminative power than a conventional boundary point distribution model (PDM)? 3) Especially, is Euclideanization of non-Euclidean shape properties important in achieving high discriminative power? Measuring the capability of a method in terms of area under the receiver operator characteristic (ROC) curve, we show that our proposed method achieves strongly better classification than both the classification method based on global volume alone and the s-rep-based classification method without proper Euclideanization of non-Euclidean GOPs. We show classification using Euclideanized s-reps is also superior to classification using PDMs, whether the PDMs are first Euclideanized or not. We also show improved performance with Euclideanized boundary PDMs over non-linear boundary PDMs. This demonstrates the benefit that proper Euclideanization of non-Euclidean GOPs brings not only to s-rep-based classification but also to PDM-based classification.

Changes in insomnia subtypes in early Parkinson disease

Objective: To examine the development of factors associated with insomnia in a cohort of originally drug-naive patients with incident Parkinson disease (PD) during the first 5 years after diagnosis. Methods: One hundred eighty-two drug-naive patients with PD derived from a population-based incident cohort and 202 control participants were assessed for insomnia before treatment initiation and were repeatedly examined after 1, 3, and 5 years. Insomnia was diagnosed according to the Stavanger Sleepiness Questionnaire. The Parkinsons Disease Sleep Scale was used to differentiate sleep initiation problems from problems of sleep maintenance. Generalized estimating equation models were applied for statistical measures. Results: The prevalence of insomnia in general was not higher in patients with PD compared to controls at the 5-year follow-up. There were changes in the prevalence of the different insomnia subtypes over the 5-year follow-up. The prevalence of solitary problems in sleep maintenance increased from 31% (n = 18) in the drug-naive patients at baseline to 49% (n = 29) after 1 year and were associated with the use of dopamine agonists and higher Montgomery-Åsberg Depression Rating Scale scores. The prevalence of solitary sleep initiation problems decreased continuously from 21% (n = 12) at baseline to 7.4% (n = 4) after 5 years; these were associated with less daytime sleepiness. Conclusions: The prevalence rates of the different insomnia subtypes changed notably in patients with early PD. The frequency of sleep maintenance problems increased, and these problems were associated with dopamine agonist use and depressive symptoms, while the total number of patients with insomnia remained stable. Our findings reflect the need for early individual assessments of insomnia subtypes and raise the possibility of intervention to reduce these symptoms in patients with early PD.

A semiautomatic tool for prostate segmentation in radiotherapy treatment planning

BackgroundDelineation of the target volume is a time-consuming task in radiotherapy treatment planning, yet essential for a successful treatment of cancers such as prostate cancer. To facilitate the delineation procedure, the paper proposes an intuitive approach for 3D modeling of the prostate by slice-wise best fitting ellipses.MethodsThe proposed estimate is initialized by the definition of a few control points in a new patient. The method is not restricted to particular image modalities but assumes a smooth shape with elliptic cross sections of the object. A training data set of 23 patients was used to calculate a prior shape model. The mean shape model was evaluated based on the manual contour of 10 test patients. The patient records of training and test data are based on axial T1-weighted 3D fast-field echo (FFE) sequences. The manual contours were considered as the reference model. Volume overlap (Vo), accuracy (Ac) (both ratio, range 0-1, optimal value 1) and Hausdorff distance (HD) (mm, optimal value 0) were calculated as evaluation parameters.ResultsThe median and median absolute deviation (MAD) between manual delineation and deformed mean best fitting ellipses (MBFE) was Vo (0.9 ± 0.02), Ac (0.81 ± 0.03) and HD (4.05 ± 1.3)mm and between manual delineation and best fitting ellipses (BFE) was Vo (0.96 ± 0.01), Ac (0.92 ± 0.01) and HD (1.6 ± 0.27)mm. Additional results show a moderate improvement of the MBFE results after Monte Carlo Markov Chain (MCMC) method.ConclusionsThe results emphasize the potential of the proposed method of modeling the prostate by best fitting ellipses. It shows the robustness and reproducibility of the model. A small sample test on 8 patients suggest possible time saving using the model.

Typologies in GPs' referral practice.

BackgroundGPs’ individual decisions to refer and the various ways of working when they refer are important determinants of secondary care use. The objective of this study was to explore and describe potential characteristics of GPs’ referral practice by investigating their opinions about referring and their self-reported experiences of what they do when they refer.MethodsObservational cross-sectional study using data from 128 Norwegian GPs who filled in a questionnaire with statements on how they regarded the referral process, and who were invited to collect data when they actually referred to hospital during one month. Only elective referrals were recorded. The 57 participants (44,5%) recorded data from 691 referrals. The variables were included in a principal component analysis. A multiple linear regression analysis was conducted to identify typologies with GP’s age, gender, specialty in family medicine and location as independent variables.ResultsEight principal components describe the different ways GPs think and work when they refer. Two typologies summarize these components: confidence characterizing specialists in family medicine, mainly female, who reported a more patient-centred practice making priority decisions when they refer, who confer easily with hospital consultants and who complete the referrals during the consultation; uncertainty characterizing young, mainly male non-specialists in family medicine, experiencing patients’ pressure to be referred, heavy workload, having reluctance to cooperate with the patient and reporting sparse contact with hospital colleagues.ConclusionsTraining specialists in family medicine in patient-centred method, easy conference with hospital consultant and cooperation with patients while making the referral may foster both self-reflections on own competences and increased levels of confidence.