DISPEL: A Python Framework for Developing Measures From Digital Health Technologies.

Goal: This paper introduces DISPEL, a Python framework to facilitate development of sensor-derived measures (SDMs) from data collected with digital health technologies in the context of therapeutic development for neurodegenerative diseases. Methods: Modularity, integrability and flexibility were achieved adopting an object-oriented architecture for data modelling and SDM extraction, which also allowed standardizing SDM generation, naming, storage, and documentation. Additionally, a functionality was designed to implement systematic flagging of missing data and unexpected user behaviors, both frequent in unsupervised monitoring. Results: DISPEL is available under MIT license. It already supports formats from different data providers and allows traceable end-to-end processing from raw data collected with wearables and smartphones to structured SDM datasets. Novel and literature-based signal processing approaches currently allow to extract SDMs from 16 structured tests (including six questionnaires), assessing overall disability and quality of life, and measuring performance outcomes of cognition, manual dexterity, and mobility. Conclusion: DISPEL supports SDM development for clinical trials by providing a production-grade Python framework and a large set of already implemented SDMs. While the framework has already been refined based on clinical trials' data, ad-hoc validation of the provided algorithms in their specific context of use is recommended to the users.

A wearable system to assist walking of Parkinson s disease patients.

BACKGROUND: About 50% of the patients with advanced Parkinson's disease (PD) suffer from freezing of gait (FOG), which is a sudden and transient inability to walk. It often causes falls, interferes with daily activities and significantly impairs quality of life. Because gait deficits in PD patients are often resistant to pharmacologic treatment, effective non-pharmacologic treatments are of special interest. OBJECTIVES: The goal of our study is to evaluate the concept of a wearable device that can obtain real-time gait data, processes them and provides assistance based on pre-determined specifications. METHODS: We developed a real-time wearable FOG detection system that automatically provides a cueing sound when FOG is detected and which stays until the subject resumes walking. We evaluated our wearable assistive technology in a study with 10 PD patients. Over eight hours of data was recorded and a questionnaire was filled out by each patient. RESULTS: Two hundred and thirty-seven FOG events have been identified by professional physiotherapists in a post-hoc video analysis. The device detected the FOG events online with a sensitivity of 73.1% and a specificity of 81.6% on a 0.5 sec frame-based evaluation. CONCLUSIONS: With this study we show that online assistive feedback for PD patients is possible. We present and discuss the patients' and physiotherapists' perspectives on wearability and performance of the wearable assistant as well as their gait performance when using the assistant and point out the next research steps. Our results demonstrate the benefit of such a context-aware system and motivate further studies.

Effect of movements on the electrodermal response after a startle event.

OBJECTIVES: In this work the effect of quasi-stationary movements on the electrodermal activity (EDA) after a startle event has been investigated and evaluated. In previous EDA research there is a discrepancy between the use of controlled environment studies and daily life surveys. This paper aims to address this by expanding the knowledge about EDA in real life applications. METHODS: A minimally obtrusive body-worn measurement device was designed and produced that simultaneously records EDA and finger movements. During this study, five subjects walked at different speeds and listened to startling sound events. The EDA response to these startle events was analyzed for different walking speeds using crosscorrelograms and cumulative frequency plots. RESULTS: The measured response to the startle event is consistent with the signal characteristics described in the literature. The results show that the faster a person is walking the more the signal property of the phasic part of the EDA is approaching a uniform distribution. However, even at a walking speed of 6 km/h the effect of the startle event is statistically still visible in the EDA (p < 0.05). CONCLUSIONS: The presented work offers a good understanding of the EDA while walking at different speeds. Although the artefacts evoked by walking cannot be determined directly, information on the movement can be useful. Depending on the walking speed a measurement about the reliability of peak detection could be introduced.

Methods for computer assisted analysis of lymphoid cell shape and motility, including Fourier analysis of cell outlines.

Locomotion of lymphocytes and other leukocytes is an essential feature of the immune system, and therefore the evaluation of the locomotor behaviour of a lymphocyte population is part of its functional analysis. Paradoxically, the locomotor status of leukocytes is usually assessed on the basis of static information, by counting the number of spherical versus non-spherical cells. In this paper we describe two methods for the measurement of shape changes in microscopic images of lymphoid cells. First we computed a simple shape change factor, coined incongruence factor, based on the degree of non-overlap of the contours of the cell at the beginning and at the end of a 1 min time interval. Second we have used Fourier analysis of the cell outline: a function describing the undulations of the cell outline is broken down into sinusoidal 'waves' of increasing frequency, each with its corresponding amplitude. The amplitude values for the first ten frequencies produced a satisfactory mathematical description of lymphoid cell shapes, and the change of these amplitudes over a 1 minute time interval produced a quantitative description of the shape alterations of the cells. We have used five approaches to evaluate the shape and shape changes in the following populations of mouse lymphoma cells: a constitutively low-motile T lymphoma cell line (BW5147), a high-motile hybridoma (BW-O-Li1) either on plastic or on a precultured fibroblast-like monolayer, BW-O-Li1 cells after penetration through the monolayer, and BW-O-Li1 cells after treatment with cytochalasin B. We compare the results from direct visual evaluation of cell shape, from computer assisted assessment of sphericity and from Fourier analysis of cell shape at one moment, with the two methods for quantitative shape change analysis. All approaches revealed a clear distinction between spherical low-motile populations, and non-spherical high-motile cells. Moreover, the incongruence factor proved to be a reliable single parameter of active cell deformation. In addition, the Fourier analysis of cell outlines produced useful measures of static shape and of dynamic shape change, at any user-defined level of accuracy.

Cilia in nematode sensory organs.

Electron microscopic studies revealed thle presenlce of true cilia in nerve processes connected with sensory organs of a nemnatodes. These structures are important in evaluating the relation between nematodes and the other aschelminths, from which they were separated partially on the basis of the supposed total absence of cilia.