EYE TRACKING AND HEAD TRACKING – THE TWO APPROACHES IN ASSISTIVE TECHNOLOGIES Dariusz Zapała, Bibianna Bałaj Abstract People with physical disabilities experience difficulties in controlling various devices, including PC. Overcoming communication barriers is a significant step towards self- determination and active interaction with the environment. This article presents a case study of application and the comparison of the efficiency of eye movements and head movements in the control of the computer by the person with physical disabilities caused by damage to the spine. We observed differences in the speed of learning, as well as precise control computer applications for various types of movements. We analysed the specific needs and capabilities of the physically disabled person using the computer independently. Key words: gaze interaction, head tracking, assistive technology 1. INTRODUCTION Time spent per day on the computer is growing more and more. We use computers for work, leisure and communication. Therefore, it is important to allow the best possible access to a computer for people with physical disabilities. For this purpose, can be used applications that allow to translate visual fixation on the choice of options. The eyes are often called the only movable part of the brain. This is the feature that was probably the inspiration for the use of eye movements as a source of information received by the computer to control it. Eye movements are fast connection between the brain and the computer. 1.1 Eyetracking The history of research using the eye movement measurement is quite long (for review, see. Wade, 2007; Westheimer, 2007; Land, 2007). Eye movements are usually recorded in the studies of reading, in the field of perceptual search tasks or experiments investigating visual attention (for review, see. Duchowski, 2002, Just, Carpenter, 1980; Rayner, Pollatsek, 1992; Rayner, 1998). Eye-tracker allows to specify which part of the image user is looking at. Viewing of the subsequent picture elements is interpreted as an indicator of the overt visual attention. Gaze focus on the most informative parts of the image. When we start to look at the picture, we invoke mental prototype of the scene and directed subsequent glance in accordance with model. A longer look may indicate an attempt to harmonise the currently viewed element with the previously-seen detail of the image (Duchowski, 2007). Eye movements move the focus of visual attention in a sequence-specific and significant regions of interest (ROI - regions of interest; AOI - area of interest) (Noton, Stark 1971a). While viewing the images and scenes, eye movements are necessary (Ditchburn, Cinsborg, 1952, Riggs, Ratliff, 1952). If all eye movements are suppressed, visual perception fades. Immobilisation of the image relatively to the retina causes the person to no longer see