Project Summary/Abstract Introduction. Parkinson's Disease (PD) is a common neurodegenerative disorder that a ects 1 million Americans and 10 million individuals worldwide. The incidence of PD increases with age, and men are 50% more likely to have PD than women. The costs of PD are estimated to be $25 billion annually in the United States alone. One of the most debilitating and impactful symptoms of PD is Freezing of Gait (FOG). Problem to be Solved. FOG, de ned as an episodic absence or marked reduction of forward progression of the feet despite the intention to walk, is a common motor symptoms of PD. FOG is a \mysterious phenomenon with a pathophysiology that is not fully understood. FOG decreases quality of life and activity level, and often leads to loss of independence and injurious falls. Although FOG is more common in the later stages of PD, it also occurs in 26% of early-stage patients. Surgical and pharmacological treatments are often ine ective in reducing FOG symptoms; however, alternate interventions can be more ecacious. External prompts, such as auditory, visual, or tactile cues, have been shown to help, but outcomes are generally mixed due to the individualized nature of FOG|various types of cues are more or less e ective depending on individuals and their present circumstances. The ParkinSense System. The proposed body-worn ParkinSense system is specially designed to help PD patients prevent FOG and resume ambulation when FOG occurs. The miniature, wireless ParkinSense instrument will be easily attachable to existing prescription or nonprescription eyeglasses, or can be worn as a low-pro le band under a cap or hat. Using sophisticated on-board six degrees-of-freedom inertial sensing and real-time processing algorithms, the ParkinSense system will automatically detect the onset of FOG and provide an individually calibrated and optimized combination of cues, including: auditory (including speech, music, or rhythmic beats), visual (transverse lines in the visual eld or blinking lights), and/or vibrotactile cues. In addition to the head-worn instrument, the ParkinSense system will include an optional limb-worn auxiliary unit. The head-worn unit will provide the main sensing and multimode cueing capabilities, and the auxiliary unit will enable supplemental sensing and cueing directly to a limb (e.g, a leg) if desired. The head-worn unit will communicate wirelessly with the limb-worn unit. The ParkinSense system will enable delivery of multiple types of cues in any combination. Cueing can be provided automatically in response to a FOG event, manually (controlled by the wearer), or continuously. Cue delivery can be optimized to provide maximum ecacy, unobtrusiveness, and comfort for individual users. Further, the ParkinSense system will have the capability to adapt its cues in real-time to match, for example, the functional step cadence of the wearer, thereby increasing ecacy.