A pressure measurement for pull test validation in postural instability assessment

The pull test (PT) is a common maneuver used by neurologist to assess the postural instability of patients with iatrogenic forms or Parkinson's disease. Postural instability is one of the main causes of the incident of falls in elderly and people with neurological disease. The pull test (PT) consists in observing the user response after providing a tug to the patients' shoulders, in order to displace the center of gravity from its neutral position. With a nonstandard backward tug, the validity of the test can be seriously compromised; this problem became more serious when the test must be supplied to the same patient alter a given period of time to assess the time evolution of the disease. In this paper is presented a preliminary analysis on the usability of pressure sensing elements, connected in a matrix 4×4, for the pull strength evaluation. A static characterization has been carried out in order to assess the measurement range along with its uncertainty band (experimentally found). Results obtained demonstrate a good force measurement range (0.242 Kg-0.642 Kg), measured in a single sensing element.