Evaluation of SpreadKey System with Motor Impaired Users

Effect of dynamic keyboard and word-prediction systems on text input speed in persons with functional tetraplegia

“…Text input speed was decreased by the dynamic keyboard compared with the static keyboard, and only one participant (the participant who scanned) chose to continue using the dynamic keyboard during the second month of the trial, suggesting a lack of subjective benefit in most cases. However, our results contrast with those of Merlin and Reynal, who showed that their dynamic keyboard improved text input speed by 20 percent compared with a static QWERTY keyboard in six participants with disabilities who used pointing systems [19]. This difference may be explained by the fact that the type of prediction system used was different.…”

“…Dynamic keyboards have existed for several years and are particularly used by people who use scanning systems [26,29] to increase text input speed and communication rate [26,30], although they were also designed for people who use pointing devices [18][19]28]. In 2009-2010, our team developed a dynamic keyboard that was intended for use by users of both scanning systems and pointing devices [28].…”

“…This difference may be explained by the fact that the type of prediction system used was different. In their system, the characters that had a low probably of being selected were replaced by those with a high probability, thus creating repetition of these characters across the keyboard and increasing the ease with which they could be selected [19]. In our keyboard, only the position of the character is altered according to its selection probability, requiring the subject to search for the desired character for each selection.…”

“…For people who use scanning devices, dynamic keyboards have been shown to reduce the number of key selections necessary or the latency between two selections; for people using pointing devices, dynamic keyboards have been shown to reduce the displacement of the cursor. Text input speed has been shown to be the same using a dynamic keyboard as a QWERTY keyboard in nondisabled subjects [18] and to increase by 20 percent in subjects with disabilities using pointing devices with a dynamic Spreadkey keyboard compared with a QWERTY keyboard [19]. However, in a study which included persons who scan, Schadle et al found an increase of 32 percent for text input time and 50 percent for the number of validations using a dynamic (linear) scanning system in comparison with a keyboard with a frequency-based organization line/column in a simulation study [20].…”

SlideKey: Impact of In-depth Previews for a Predictive Text Entry Method

“…This solution consists of predicting the next character. This makes it easier to point the keys containing the most probable characters either by enlarging these keys [1,6], by adding additional keys [7], or by increasing the speed of the pointer according to its position [8]. But, this type of solution is mostly used for single-switch scanning using a virtual keyboard [4].…”