Buchstabenstreichung

The cancellation paradigm dates to Bourdon (1895) and remains in clinical use as the d2 test.

You scan a dense grid for targets and mark them. Misses + false alarms = attention errors.

It's a visual analog of go/no-go: you go on targets, withhold on distractors.

Used to assess ADHD, neglect, and visual attention deficits.

Each test is constructed using Item Response Theory (IRT) and Classical Test Theory (CTT) to ensure reliable measurement of knowledge and ability across different difficulty levels.

Questions undergo rigorous review including difficulty calibration, discrimination analysis, and distractor effectiveness evaluation to maintain high assessment quality.

1. Note the target letter at top.
2. Click every instance of that letter in the grid.
3. You can't un-click — verify before each tap.
4. Faster + more accurate = higher score.