Keyboard layout in eye gaze communication access: typical vs. ALS

Abstract

The purpose of the current investigation was to determine which of three keyboard layouts is the most efficient for typical as well as neurologically-compromised first-time users of eye gaze access. All participants (16 neurotypical, 16 amyotrophic lateral sclerosis; ALS) demonstrated hearing and reading abilities sufficient to interact with all stimuli. Participants from each group answered questions about technology use and vision status. Participants with ALS also noted date of first disease-related symptoms, initial symptoms, and date of diagnosis. Once a speech generating device (SGD) with eye gaze access capabilities was calibrated to an individual participant's eyes, s/he practiced utilizing the access method. Then all participants spelled word, phrases, and a longer phrase on each of three keyboard layouts (i.e., standard QWERTY, alphabetic with highlighted vowels, frequency of occurrence). Accuracy of response, error rate, and eye typing time were determined for each participant for all layouts. Results indicated that both groups shared equivalent experience with technology. Additionally, neurotypical adults typed more accurately than the ALS group on all keyboards. The ALS group made more errors in eye typing than the neurotypical participants, but accuracy and disease status were independent of one another. Although the neurotypical group had a higher efficiency ratio (i.e. accurate keystrokes to total active task time) for the frequency layout, there were no such differences noted for the QWERTY or alphabetic keyboards. No differences were observed between the groups for either typing rate or preference ratings on any keyboard, though most participants preferred the standard QWERTY layout. No relationships were identified between preference order of the three keyboards and efficiency scores or the quantitative variables (i.e., rate, accuracy, error scores). There was no relationship between time since ALS diagnosis and preference ratings for each of the three keyboard layouts. It appears that individuals with spinal-onset ALS perform similarly to their neurotypical peers with respect to first-time use of eye gaze access for typing words and phrases on three different keyboard layouts. Ramifications of the results as well as future directions for research are discussed.