A multisensor architecture for the assessment of postural sway in elderly and people with neurological disease

Postural instability is one of the symptoms of Parkinson's disease which can cause falls with possible unpleasant consequences. Two main tests, the Timed Up and Go and the Pull Test, are typically performed by physicians to assess the postural instability of patients. Such tests require on purpose structured laboratory equipped with expensive monitoring systems. Moreover, in the case of Pull test, the validity of the tests can be compromised by the nonstandard backward tug provided to the patient. The solution proposed in this paper consists of a low cost multisensor system and a methodology which allows to implement an objective estimation of the input solicitation as well as the assessment and classification of the user response. Different parameters (10) presented in the literature for the sake of the postural instability evaluation were investigated, in case of Pull Test, with a large set of experiments (59) in order to extract a set of features useful for the classification between stable and unstable behavior. Results obtained demonstrated the feasibility of the methodology proposed.