What the exercise is
Cancellation tasks ask a person to find and mark every target in a field of targets and distractors. People with unilateral (hemispatial) neglect, most often after right-hemisphere stroke, tend to miss targets on the side opposite the lesion. That makes cancellation useful for practising systematic scanning and for seeing whether omissions are lopsided.
CogniStride scatters gold stars among outline stars, circles, triangles, squares, diamonds and crosses, with the same number of target stars on each half of the field. Tapping a star crosses it out; tapping anything else counts as a false positive.
Cueing levels
- No cue. Plain field.
- Left anchor line. A red vertical line on the left edge gives scanning a starting point.
- Anchor + flashing left border. The left edge pulses to draw attention.
- Anchor + flash + verbal cue. A spoken prompt at the start, repeated every 20 seconds while stars remain on the left.
Recording the cue level with each result shows whether a patient is managing with less support over time.
What is recorded
| Measure | What it means |
|---|---|
| Left and right detection | Targets found on each half, as counts and percentages |
| Centre of cancellation (CoC) | Where found targets sit relative to all targets, from −1 (left) to +1 (right). CogniStride flags values beyond ±0.081 as a lateral bias. |
| False positives | Non-targets tapped, split by side |
| Time and start side | Seconds to finish, and which side the first star was found on |
Heatmap and search path
When the patient finishes, the field is overlaid with a 6×4 heatmap: regions with missed stars are shaded red in proportion to how many were missed, complete regions turn green, and each missed star is circled. A blue line connects found stars in the order they were tapped, starting from a dot, so you can see whether scanning was organised or scattered.
Limits
This is a practice task based on the paper star cancellation format, not a standardised neglect assessment, and the CoC flag is a prompt for clinical attention, not a diagnosis. The guide Star cancellation & visual scanning for left neglect explains how to read these numbers.