A brain training app for teens. Four cognitive exercises based on real neuropsychology, wrapped in a gamified PWA that works offline.
Built with zero frameworks — just TypeScript, CSS, and the Web Audio API.
Four cognitive exercises, each targeting a specific executive function:
| Exercise | What it trains | Key metric |
|---|---|---|
| Go/No-Go | Impulse control | Commission errors, RT variability |
| N-Back | Working memory | d-prime (signal detection) |
| Flanker | Selective attention | Interference score |
| Visual Search | Visual scanning | Search slope (ms/item) |
Plus breathing exercises (box 4-4-4, relaxation 4-7-8) and a Pomodoro timer.
Each exercise adapts across 10 difficulty levels based on your recent scores. The difficulty engine uses tighter thresholds than typical apps (75/65 instead of 80/60) to keep you in the optimal learning zone.
This isn't a casual brain game. The metrics come from actual neuropsychological assessment:
- IIV (intra-individual variability) — RT consistency is the strongest marker of attention problems in teens
- Lapse detection — flags responses >3 SD above your mean RT (momentary attention lapses)
- Lure trials in N-Back — items that match at N+1 or N-1, not N. Catches familiarity-based false alarms
- Neutral trials in Flanker — separates facilitation (congruent faster than neutral) from inhibition cost (incongruent slower than neutral)
- Search slope — linear regression of RT vs set size. Steeper = less efficient visual processing
- Baseline assessment — fixed Level 1 test every 20 sessions to measure real improvement vs practice effects
All scored per-exercise, not averaged into a meaningless composite number.
The engagement system is designed around ADHD-specific reward sensitivity:
- Streak system with freeze protection — earn 1 freeze per 7-day streak (max 3). Miss a day, freeze auto-activates. Soft "keep your streak" messaging instead of punishing "streak lost" anxiety
- Daily challenges — 12 types, deterministic per day (same for all users), with difficulty guards so new users don't get impossible challenges
- Quick / Standard / Deep sessions — 1-minute quick session goes straight to your weakest exercise, no mood modal, no plan screen. Removes the activation barrier
- Level-up celebrations with sound, haptics, confetti, and unlock announcements
- Badge ceremonies — 7 badges x 3 tiers, shown as full-screen overlays with share button
- Daily login bonus — 10 XP just for opening the app
- 30 levels with named titles (Newcomer through Absolute), theme unlocks at 5/10/15/20
The feedback language is ADHD-friendly throughout: "Hold steady!" instead of "Don't press!", tiered encouragement at every score level, and the app tells you when difficulty adjusts ("We matched the difficulty to your pace").
English, Russian, German, French, Spanish. Auto-detects browser language. Switch anytime (reloads the app). All 390+ translation keys verified for parity across all 5 languages.
| Language | TypeScript (strict) |
| Bundler | esbuild |
| Tests | Vitest — 270 tests across 13 files |
| Audio | Web Audio API (procedural, no files) |
| Fonts | Self-hosted Inter + Space Grotesk (no Google Fonts CDN) |
| State | Custom reactive store with localStorage persistence and cross-tab sync |
| Router | Hash-based SPA router with param extraction |
| PWA | Service worker, manifest, offline-first, installable |
| Frameworks | None |
Bundle: ~380kb JS, ~70kb CSS. Zero external requests.
npm install
npm run dev # dev server with live rebuild
npm test# 270 tests
npm run build # production build to dist/Requires Node 18+.
public/
js/
core/ # state, storage, adaptive difficulty, progression, streaks, i18n
exercises/ # go-no-go, n-back, flanker, visual-search, breathing, pomodoro
ui/screens/ # dashboard, exercise-play, results, stats, settings, onboarding
ui/components/ # nav, avatar, charts, streak-display, celebrations, confetti
i18n/ # en, ru, de, fr, es translation files
css/ # design tokens, components, layout, exercises, animations, fonts
tests/ # 13 test files covering all core logic
plans/ # feature plans and domain expert reviews
The exercises are based on validated paradigms (Go/No-Go, N-Back, Eriksen Flanker, Visual Search) from the ADHD and executive function literature. This app is for cognitive training and self-improvement — not clinical diagnosis. It does not replace professional assessment.
TBD