Elderly users suffering from hand tremor have difficulties interacting with touchscreens because of finger oscillation. It has been previously observed that sliding one's finger across the screen may help reduce this oscillation. In this work, we empirically confirm this advantage by (1) measuring finger oscillation during different actions and (2) comparing error rate and user satisfaction between traditional tapping and swabbing in which the user slides his finger towards a target on a screen edge to select it. We found that oscillation is generally reduced during sliding. Also, compared to tapping, swabbing resulted in improved error rates and user satisfaction. We believe that swabbing will make touchscreens more accessible to senior users with tremor.

Interacting with touchscreen computer systems is a challenging task for elderly tremor patients, because of a lower input accuracy caused by their tremor symptoms. Previous observations by Mertens et al. suggested that continuous movements are able to lower these symptoms. In this paper Swabbing, a input method for touchscreen systems based on such motions, is presented. A user study will show that Swabbing is able to reduce the error rate while proving equal user satisfaction compared to standard input techniques. Furthermore reasons for these benefits will be argued and explained with the use of accuracy measures by MacKenzie et al. In the end possible future enhancements of Swabbing will be discussed.

Abstract. As a result of demographic change the average age of many western populations increases, accompanied with age-related disease patterns. Especially tremor symptoms rise accordingly, aggravating a barrier free interaction with information systems. In order to maintain a self determined lifestyle at home, new technologies and methods need to be introduced, especially for application in health care and telemedical scenarios. Hence, a new direct input technique based on wiping movements on touch screens has been developed. The combination of a new input concept and applying regular commercially available technologies helps to avoid high costs for acquisition and therefore makes it marketable. While making an input on the touch screen the precise characteristics of every wiping movement can be tracked and is used for computation of the desired entry. The efficacy of this approach was evaluated within a clinical study with n=15 subjects. The results show that the error ratio for inputs by tremor patients can be significantly reduced in comparison to a virtual keyboard, depending on tremor strength and form. The learning curve for first time users is very steep and tends to result in inputs that are only slightly steady than purposeful movements to standard buttons and keys.