mHealth Research Digest with Tim Bredrup

Chronic pain is a multidimensional experience. Consisting of both physiological and psychological factors, it has a significant impact on how a patient functions physically, emotionally, and socially.

Developing reliable assessment tools that are capable of capturing the dynamic impact of chronic pain has been challenging, and many current tools used in clinical practice rely on self-reporting, which is purely subjective.

To address these issues, researchers in Switzerland performed a study that provides a comprehensive analysis of real life physical activity to attempt to capture behavioral aspects reflecting physical and emotional functioning.

60 chronic pain patients and 15 pain-free subjects participated in the study by having their physical activity monitored for five consecutive days. To assess the different aspects of pain-related activity behaviors, the concept of physical activity “barcoding” was defined. The patients included those suffering from chronic pain caused by failed back surgery syndrome (n = 21), spinal stenosis (n = 19), peripheral vascular disease (n = 8), and combined pathologies (n = 12). Patients used the visual analog scale (VAS) to report their pain and their scores divided into three tiers, ‘no pain’, ‘mild’, ‘moderate’ and ‘severe’.

“The main idea was to combine different features of physical activity (type, intensity, duration) to define various physical activity states,” the researchers explained. “The temporal sequence of different states was visualized as a ‘barcode’ (see image above) which indicated that significant information about daily activity can be contained in the amount and variety of physical activity states, and in the temporal structure of sequence.”

To quantify this information the researchers used a variety of complementary measures including “time spent in physical activity states, and two composite scores, which integrate all measures.”. Reliability of the chronic pain measured was assessed by comparing subject groups with varied levels of pain to each other.Physical activity was measured using “under free living conditions” using three miniature accelerometers stuck to the skin with medical adhesive patches. Different “states” of physical activity were defined by the researchers and complex statistics used to aggregate patterns of activity.

“The defined measures of physical activity showed good discriminative features,” the study authors declared. “The results suggest that significant information about pain-related functional limitations is captured by the structural complexity of physical activity … which decreases when the intensity of pain increases.”

The researchers went on to conclude that “a comprehensive analysis of daily-life physical activity can provide an objective appraisal of the intensity of pain.”


Authors: Anisoara Paraschiv-Ionescu, Christophe Perruchoud, Eric Buchser, Kamiar Aminian

Institutions: Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland; Anesthesia and Pain Management Department, EHC, Hospital of Morges, Morges, Switzerland; Department of Anesthesiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland

Original Abstract