We plan to develop a Head-mounted Positional Management System (HPM System) for diagnosis and treatment of vestibular disorders for widespread application at medical and research facilities. Utilizing a spatial orientation sensor that can track head movement, coupled with state-of-the-art 3-D eye movement recording and analysis methods, the system will analyze eye movement (nystagmus) and spatial orientation of the head, display the data, and provide interpretive guidelines to assist the operator in carrying out complex repositioning maneuvers manually on an exam table. During Phase I we will design a wireless prototype headset combining a head-tracking system with a video nystagmus analysis and monitoring system to display graphically the ongoing spatial orientation of the subject's semicircular canals and indicate which semicircular canal is creating the nystagmus. A decision support system will offer guidance (pictorial, textual) in undertaking diagnostic and treatment maneuvers, and will monitor the precision of the user's maneuvers. We will also validate performance by demonstrating the added value of the HPM System by performing feasibility studies in a small subject cohort (n=15) with positional vertigo. We will validate performance by determining the added value of the HPM System compared to diagnosis and treatment with the best commercially available equipment. During Phase II, we anticipate that engineering modifications of the headset will be made based upon Phase I findings. Additional systems will be added to the headset, or as peripheral modules, to develop an advanced decision support system. Production models will be installed at several beta sites for conduction of human studies in a larger subject population to obtain more definitive validation and user acceptance testing.