Out-of-home activity recognition from GPS data in schizophrenic patients

Sonia Difrancesco, Paolo Fraccaro, Sabine N Van Der Veer, Bader Alshoumr, John Ainsworth, Riccardo Bellazzi, Niels Peek

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Risk of psychotic relapse in schizophrenic patients is commonly measured by social functioning (SF), which focuses on patients' daily activities. Monitoring of SF usually relies on infrequent clinic visits, limiting the capacity to detect sudden changes. GPS data that is passively collected with smartphones introduce new opportunities to monitor SF. We conducted a five-day pilot study with five schizophrenic patients to assess the feasibility of this approach. Participants used a smartphone to continuously record their GPS location, and completed a paper-based SF diary to register out-of-home activities. We implemented a time-based method and a density-based method to identify the geolocations visited and then we clustered geolocations visited in places visited. Finally, we used semantic enrichment to classify places types and associated activities. We evaluated the performance of the two approaches by comparing the activities detected from the GPS data with those recorded in the SF diary. Recall was better for the density-based method, ranging from 0.686 (Standard Deviation [SD] 0.168) to 0.771 (SD 0.264) while precision was better for the time-based method (0.722 (SD 0.197) to 0.954 (SD 0.093)). To conclude, using routinely collected GPS data and relatively simple analytical methods we detected patients' out-of-home activities with moderate recall, more sophisticated analytical methods may obtain better performance.

Original languageEnglish
Title of host publicationProceedings - IEEE 29th International Symposium on Computer-Based Medical Systems, CBMS 2016
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
ISBN (Electronic)9781467390361
Publication statusPublished - Aug 16 2016
Event29th IEEE International Symposium on Computer-Based Medical Systems, CBMS 2016 - Belfast, Ireland
Duration: Jun 20 2016Jun 23 2016


Other29th IEEE International Symposium on Computer-Based Medical Systems, CBMS 2016


  • Global Positioning System
  • Out-of-home mobility
  • Schizophrenia
  • Smartphone
  • Social functioning

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Computer Science Applications


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