The Cost of Turning Heads: A Comparison of a Head-Worn Display to a Smartphone for Supporting Persons with Aphasia in Conversation
Kristin Williams, Karyn Moffatt, Jonggi Hong, Yasmeen Faroqi-Shah, Leah Findlater · 2016 · ASSETS '16: Proceedings of the 18th International ACM SIGACCESS Conference on Computers and Accessibility · doi:10.1145/2982142.2982165
Summary
This study directly compares head-worn displays (HWDs) to smartphones for providing vocabulary support to people with aphasia—an acquired language disorder caused by brain damage (typically stroke) that affects word-finding, comprehension, and language formulation. While symbol-based dictionaries on smartphones and dedicated AAC devices can provide vocabulary prompts, using them requires looking away from the conversation partner, disrupting eye contact, verbal inflection monitoring, and natural conversation flow. The researchers recruited 20 people with aphasia to use both a Google Glass HWD and a Samsung smartphone while playing Go Fish—a card game requiring structured verbal exchanges. Both devices ran identical vocabulary-prompting software with a two-level hierarchy of action and object words, plus text-to-speech capability. A custom Arduino-based remote control with tactile buttons addressed motor accessibility issues with Google Glass's touchpad, accommodating users with right-sided hemiparesis from stroke. The study measured communication efficiency (time per turn, vocabulary words retrieved), task success (card pairs matched), and subjective experience. Semi-structured interviews explored design preferences, privacy concerns, aesthetic considerations, and how each device might fit within participants' existing communication practices and support systems.
Key findings
The HWD enabled significantly more efficient communication, with average time per turn of 36.3 seconds compared to 71.0 seconds for the smartphone (p=.043, d=1.00—a large effect size). This efficiency gain is substantial for real conversations where delays can lead to losing speaking turns. HWD users matched more card pairs (11.3 vs 7.6 out of 20 possible) and retrieved more vocabulary words from the device (6.8 vs 4.6), though these differences did not reach statistical significance despite large effect sizes (d=0.82 and d=0.66 respectively). Overall experience was rated higher for the HWD (6.1 vs 4.6 on 7-point scale). Surprisingly, no significant differences emerged for perceived focus on conversation or partner—contrary to the hypothesis that HWDs would support better attention. A secondary analysis revealed that "fast performers" (under 45 seconds per turn) used devices more frequently, matched more cards, and reported higher focus ability regardless of form factor, suggesting individual adeptness with technology may matter more than device type. Qualitative findings revealed design tensions: while HWDs offered privacy and glanceability, they were more noticeable as assistive devices. Participants wanted HWDs miniaturized into existing eyewear frames, with modular audio components, and the ability to selectively conceal or reveal vocabulary support.
Relevance
This research provides empirical evidence for the "cost of turning heads"—the measurable communication penalty imposed when AAC users must divert attention to external devices. The significant efficiency advantage of HWDs (nearly 2x faster communication) has real implications for conversation dynamics, where response delays can signal incompetence or cause speakers to lose their turn. For AAC practitioners and developers, the study highlights that form factor is not merely a convenience issue but directly impacts communication outcomes. The design insights are actionable: users want devices that integrate with prescription eyewear, offer selective visibility (to control disclosure of disability), provide private audio output, and fit within existing support ecosystems rather than replacing them. The finding that individual technology adeptness predicted success across both devices suggests that training and extended practice periods may be as important as device selection. Future work should examine longer-term adoption patterns and whether HWD benefits persist in naturalistic settings with unfamiliar conversation partners.
Tags: aphasia · AAC · augmentative and alternative communication · head-worn display · wearable computing · conversation support · vocabulary support · Google Glass