Contextual Exploration of Mathematical Formulae on the Web for People with Visual Disabilities in Brazil with an Open-Source Screen Reader
Hérlon Manollo Cândido Guedes, Paula C. F. Cardoso, William Massami Watanabe, André Pimenta Freire · 2022 · Proceedings of the 21st Brazilian Symposium on Human Factors in Computing Systems (IHC) · doi:10.1145/3554364.3559134
Summary
This paper presents the implementation and evaluation of Access8Math-NavMatBR, an NVDA screen reader add-on for reading and exploring mathematical formulae on the web in Brazilian Portuguese. The add-on implements contextual exploration — a strategy where formulae are semantically grouped into simple and complex elements, allowing users to navigate at different levels of abstraction rather than reading linearly or navigating a raw tree structure. When encountering a formula, the screen reader either reads simple elements directly or announces the type of complex structure (e.g., "fraction"), which users can then expand to explore its contents. The system uses NVDA's standard navigation keys rather than requiring users to memorize new shortcut keys for each mathematical element type. The researchers built on the open-source Access8Math add-on and evaluated with six participants with visual disabilities (ages 27-42, 9-15 years of screen reader experience) using think-aloud usability testing. Participants read four formulae of increasing complexity — from simple expressions to the quadratic formula — and answered comprehension questions. The study addresses a significant gap: few screen readers support mathematical content reading in Portuguese, and no contextual exploration tools existed for Brazilian Portuguese users.
Key findings
The evaluation identified 52 instances of usability issues across three themes: formula interaction (22 occurrences), formula narration (27 occurrences), and platform concerns (3 occurrences). These were categorized into 26 distinct problem types. Key interaction problems included users not understanding they could explore inside abstract elements like fractions and roots, difficulty navigating between abstraction levels (zoom in/out), and unclear shortcut key behavior. Major narration issues included confusion between division and fractions (both narrated as "fração"), difficulty understanding root index descriptions, insufficient pauses between numerator and denominator, and reading speed being too fast for complex expanded elements. Despite these issues, participants rated the contextual exploration approach positively: median scores of 4.5/5 for reducing ambiguity and 5/5 for improving formula comprehension. Participants compared the contextual navigation to familiar Excel spreadsheet navigation patterns. The use of standard NVDA navigation keys rather than element-specific shortcuts facilitated learning and memorization.
Relevance
This research highlights the critical gap in STEM accessibility for non-English-speaking users. While mathematical accessibility tools exist for English, the lack of Portuguese language support in major screen readers creates a significant barrier for Brazilian students and professionals with visual disabilities. The contextual exploration approach — abstracting complex elements and allowing progressive disclosure — offers a model for making any hierarchically structured content more navigable by screen reader users. The finding that users naturally compared formula navigation to Excel spreadsheet navigation suggests that leveraging familiar interaction paradigms can reduce the learning curve for specialized accessibility tools. The 52 usability issues documented provide a detailed roadmap for improving mathematical screen reader support, with implications extending beyond Portuguese to any language implementing formula reading. The study also underscores the importance of open-source screen readers like NVDA for enabling community-driven accessibility solutions in underserved language markets.
Tags: mathematical accessibility · screen readers · NVDA · MathML · visual disability · Portuguese language · contextual exploration · STEM accessibility
Standards referenced: WCAG 2.0 · MathML 3.0