Experiences of Someone with a Neuromuscular Disease in Operating a PC (and Ways to Successfully Overcome Challenges)
Torsten Felzer, Stephan Rinderknecht · 2015 · ACM Transactions on Accessible Computing (TACCESS) · doi:10.1145/2700436
Summary
This paper describes the first-person experiences of the first author, who has Friedreich's Ataxia (FA) — a progressive neuromuscular disease causing ataxia of limbs, dysarthria, and muscle weakness — in finding a viable computer input method over 25 years. Diagnosed at age 15 and wheelchair-dependent since 18, the first author is an active HCI researcher whose occupation requires near-constant computer use, yet his declining motor function made standard keyboards and mice increasingly difficult to operate. The paper details his systematic evaluation and rejection of numerous existing alternatives: speech recognition failed due to dysarthria (Dragon could not understand the required training sentence after 50+ attempts), eye tracking was impossible due to pathological nystagmus causing uncontrollable eye movements, camera-based head tracking was too unsteady, Dasher required fine motor control he lacked, brain-computer interfaces were too slow, and scanning-based systems underutilized his remaining abilities. The solution he developed is OnScreenDualScribe, a software system paired with a small off-the-shelf numeric keypad (the DualPad) held with both hands in landscape orientation and operated with the thumbs. The system offers three text entry modes: dual mode (row-column selection on a virtual 8x6 grid, two keystrokes per character), word prediction mode (dictionary-based completion), and ambiguous mode (T9-like input where six keys map to the entire alphabet, with dictionary disambiguation). It also includes three mouse emulation modes, including the novel DualMouse which uses recursive tile-based target acquisition — the screen is divided into a grid, the user selects a tile, which subdivides into subtiles, and this zooms in until pixel-level precision is achieved, entirely without time pressure.
Key findings
Over a threefold pilot study spanning three years (2011-2014), the first author's entry rate with OnScreenDualScribe increased from 1.38 WPM to 6.16 WPM, while his typing rate on a standard keyboard declined from 12 WPM (in the 1990s) to 3.5 WPM over 24 years due to disease progression. By May 2014, OnScreenDualScribe had effectively "turned back the clock" 10 years, reaching a performance level comparable to his standard keyboard speed a decade earlier — and still improving, not yet reaching a plateau. The key advantages of the DualPad are: hands never need repositioning (all keys reachable by thumbs), physical edges serve as tactile guides preventing accidental key strikes, keys are large enough for imprecise thumb movements, and the compact form factor works on any surface including in bed. In ambiguous mode, the first author uses it for 80% of text composition, 10% for editing in single keystroke mode, and 10% for numbers and symbols. The system replaces both keyboard and mouse completely — the first author stopped using a standard keyboard entirely because OnScreenDualScribe was not only less effortful but had actually surpassed his declining typing speed. The cognitive load trade-off is acknowledged: the system demands more visual attention and mental effort than a standard keyboard, and entry rate decreases with fatigue.
Relevance
This paper is a rare and valuable first-person account of living with a progressive motor disability and the iterative, decades-long search for viable computer access. The autoethnographic approach provides insights that third-person studies cannot capture — the emotional toll of declining ability, the frustration of systems that almost work, and the transformative impact of finding an effective solution ("writing emails is now more like fun"). For AT designers, the paper illustrates a critical design principle: the gap between "no ability" and "some ability" is enormous. Systems designed for users who can only produce one input signal (scanning, BCI) dramatically underserve users who retain moderate motor function — the first author needed a system that made optimal use of his remaining thumb dexterity, not one that assumed minimal input. The DualMouse's time-pressure-free pointing method is particularly innovative for users with ataxia, where stopping movement at precisely the right moment is the core challenge. The paper also serves as a powerful argument for user-developer overlap in assistive technology — the most successful solution was one the user built for himself, incorporating insights that no external designer would have had.
Tags: motor impairment · text entry · alternative input device · neuromuscular disease · keyboard replacement · word prediction · mouse emulation · DIY assistive technology · autoethnography