Barcoding human physical activity to assess chronic pain conditions.

Ken R Duffy,Anisoara Paraschiv-Ionescu,Kamiar Aminian,Eric Buchser,Christophe Perruchoud

doi:10.1371/journal.pone.0032239

Ken R Duffy, Anisoara Paraschiv-Ionescu + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0032239

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Abstract

BackgroundModern theories define chronic pain as a multidimensional experience – the result of complex interplay between physiological and psychological factors with significant impact on patients' physical, emotional and social functioning. The development of reliable assessment tools capable of capturing the multidimensional impact of chronic pain has challenged the medical community for decades. A number of validated tools are currently used in clinical practice however they all rely on self-reporting and are therefore inherently subjective. In this study we show that a comprehensive analysis of physical activity (PA) under real life conditions may capture behavioral aspects that may reflect physical and emotional functioning.MethodologyPA was monitored during five consecutive days in 60 chronic pain patients and 15 pain-free healthy subjects. To analyze the various aspects of pain-related activity behaviors we defined the concept of PA ‘barcoding’. The main idea was to combine different features of PA (type, intensity, duration) to define various PA states. The temporal sequence of different states was visualized as a ‘barcode’ which indicated that significant information about daily activity can be contained in the amount and variety of PA states, and in the temporal structure of sequence. This information was quantified using complementary measures such as structural complexity metrics (information and sample entropy, Lempel-Ziv complexity), time spent in PA states, and two composite scores, which integrate all measures. The reliability of these measures to characterize chronic pain conditions was assessed by comparing groups of subjects with clinically different pain intensity.ConclusionThe defined measures of PA showed good discriminative features. The results suggest that significant information about pain-related functional limitations is captured by the structural complexity of PA barcodes, which decreases when the intensity of pain increases. We conclude that a comprehensive analysis of daily-life PA can provide an objective appraisal of the intensity of pain.

Highlights

Pain is one of the major universal experiences of human beings defined by the International Association for the Study of Pain (IASP) as ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’ [1]
The results suggest that significant information about pain-related functional limitations is captured by the structural complexity of physical activity (PA) barcodes, which decreases when the intensity of pain increases
We conclude that a comprehensive analysis of daily-life PA can provide an objective appraisal of the intensity of pain

Summary

Introduction

Pain is one of the major universal experiences of human beings defined by the International Association for the Study of Pain (IASP) as ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’ [1]. A number of validated tools such as the visual analog scale and quality of life questionnaires have been developed to assess pain but they have several limitations [5]: (i) they relay on self-reporting and recall and are subjective and prone to biases [6]; (ii) they cannot be used in subjects with cognitive impairment as well as in some of the elderly and/or very young patients [7] ; (iii) they fail to capture the dynamic nature of pain and its impact on the aspects of daily-life functioning since the assessment/quantification of pain status is based on a static index at one point in time. Unlike most of the self-reporting, inherently subjective pain outcomes, the monitoring of behavioral patterns of daily physical activity may provide an objective and dynamic integrated appraisal of the impact of pain on the physical, social and emotional functioning of chronic pain patients. Modern theories define chronic pain as a multidimensional experience – the result of complex interplay between physiological and psychological factors with significant impact on patients’ physical, emotional and social functioning. In this study we show that a comprehensive analysis of physical activity (PA) under real life conditions may capture behavioral aspects that may reflect physical and emotional functioning

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