Enabling devices, empowering people: The design and evaluation ofTrackball EdgeWrite

Effect of diagnosis, body site and experience on text entry rate of individuals with physical disabilities: a systematic review

OBJECTIVE

This study systematically reviewed the research on computer text entry by people with physical disabilities, and conducted a quantitative synthesis of text entry rates associated with individuals' diagnosis, body site used with the interface and their level of experience.

METHOD

We searched 10 databases and included studies in which: typing speed was reported; the access interface was available for public use; and individuals with physical impairments were in the study population. For quantitative synthesis, we used only the text entry rates (TER) reported for individuals with physical impairments; studies also had to report the sample size, and the average and standard deviation for the text entry rates.

RESULTS

Thirty-nine studies involving 248 subjects met the criteria for quantitative synthesis. Cerebral palsy was associated with significantly slower TER, at 5.5 wpm, than muscular dystrophy (12.5 wpm), spina bifida (10.4 wpm), SCI high cervical (10.1 wpm) and SCI low cervical (13.3 wpm). Among the 19 body sites represented, the Fingers bilateral category had the highest average, at 17.72 wpm. Head (2.92 wpm) and Hand (non-typing) (3.95 wpm) were each associated with significantly slower TER than Hands unspecified, Fingers bilateral, Hand with control enhancer, Voice and Mouth. The three levels of experience examined, LowPlus, Medium and High, provided very similar TER.

CONCLUSION

This study contributes external evidence for service providers who provide computer access interventions for individuals with disabilities. The analyzed text entry performances serve as benchmarks to be used as guidelines during interface selection and training. Implications for Rehabilitation The median text entry rate (TER) across the literature for individuals with physical disabilities is 7.0 wpm. TER is affected by a user's diagnosis and the body site used for typing. These TER data can serve as diagnostic norms and benchmarks to be used as guidelines during interface selection and training. We recommend that practitioners measure text entry rate with clients, to place their performance in the context of these results and provide a baseline against which to measure effectiveness of an intervention.

Text entry rate of access interfaces used by people with physical disabilities: A systematic review

This study systematically reviewed the research on assistive technology (AT) access interfaces used for text entry, and conducted a quantitative synthesis of text entry rates (TER) associated with common interfaces. We searched 10 databases and included studies in which: typing speed was reported in words per minute (WPM) or equivalent; the access interface was available for public use; and individuals with physical impairments were in the study population. For quantitative synthesis, we used only the TER reported for individuals with physical impairments. Studies also had to report the sample size, and the average and standard deviation for the TER data. Thirty-nine studies met the criteria for quantitative synthesis. Studies involved seven interface types: standard keyboard typing, on-screen keyboard (OSK) with cursor selection, OSK with scanning selection, automatic speech recognition (ASR), Morse code, brain-computer interface (BCI), and other. ASR, standard keyboard, cursor OSK, and scanning OSK had at least four studies and 30 subjects, with TER averaging 15.4, 12.5, 4.2, and 1.7 WPM, respectively. When combined with measurements of a particular client's text entry performance, the TER from this review can be used within an evidence-based decision-making process for selecting control interfaces.

Hand usage pattern and upper body discomfort of desktop touchscreen users

A laboratory study was conducted to determine how users of different handedness interact with desktop touchscreen displays and how the hand usage pattern influences their body discomfort development. Twenty-one participants in three different handedness groups conducted simple web-browsing for 30 minutes using a 23″ touchscreen display while their subjective body discomfort, frequency of use of each hand and touch area preference were periodically quantified. Participants reported a gradual increase in body discomfort during web-browsing, and the increments in body discomfort varied between handedness groups for some body parts. Results also show that right-handed participants had stronger laterality than the left-handed, and ambidextrous participants used both hands more evenly than other participants, suggesting associations between the hand usage pattern and body discomfort development. Findings of the current study suggest that body discomfort of desktop touchscreen display users could be moderated by user-interface improvements and user training.

PRACTITIONER SUMMARY

Body discomfort development of desktop touchscreen users may be influenced by their hand usage pattern. Findings of this laboratory study suggest that user discomfort may be moderated by placing menu items in the lower area within the display or training users to alternate hands when conducting touch gestures.