Parkinson’s disease (PD) is a common neurological disorder caused by the progressive loss of dopaminergic and other subcortical neurons. PD patients often suffer from impaired motor skills. Freezing of gait (FOG) has been associated mainly with PD but can be seen in other extrapyramidal movement disorders, such as progressive supranuclear palsy and its subtype, the “pure freezing syndrome”, and in vascular parkinsonism. PD patients who experience FOG frequently report that their feet are inexplicably glued to the ground during the FOG episodes. Although FOG episodes generally appear more frequently during the OFF state, gait deficits in PD patients are often resistant to pharmacological treatment. Therefore, effective nonpharmacological treatments need to be developed as an adjunct therapy to relieve symptoms and improve mobility. A “personal health assistant” comprises a wearable sensing and communicating system, seamlessly embedded in one’s daily outfit. Several on-body sensors identify the biometric and contextual status of the wearer continuously.