Copy of Cube Task

Version: v1 (current)

A visuospatial construction task assessing the ability to reproduce a three-dimensional cube drawing.

Overview

The Copy of Cube task asks participants to copy a drawing of a three-dimensional cube (Necker cube). This classic neuropsychological test assesses visuospatial perception, constructional ability, and spatial reasoning. Performance reflects the integration of visual perception, motor planning, and spatial representation.

The task is sensitive to right parietal lobe dysfunction, dementia, and visuospatial deficits. It's commonly included in cognitive screening batteries (e.g., MoCA, MMSE variants) and neuropsychological assessments.

Scientific Background

Classic Findings:

• Developmental Trajectory: Children acquire 3D drawing ability around ages 7-9
• Aging Sensitivity: Older adults may show reduced accuracy, especially with Alzheimer's disease
• Neuroanatomical Correlates: Right parietal lobe lesions impair performance
• Scoring Criteria: Parallel lines, correct angles, 3D perspective

Why Researchers Use This Task

1. Dementia Screening: Sensitive to visuospatial decline in Alzheimer's disease
2. Neuropsychological Assessment: Evaluate constructional apraxia and spatial deficits
3. Developmental Studies: Track visuospatial development in children
4. Parietal Function: Assess integrity of parietal spatial processing

Where to Configure

Study Form → Tasks → Copy of Cube → Configure.

Configuration Parameters

Parameter	Type	Default	Description
Show Reference	boolean	true	Display reference cube alongside the canvas
Time Limit (ms)	number	120000	Time limit for drawing (default: 2 minutes)

Participant Flow

1. The participant sees a reference cube image displayed next to a blank drawing canvas.
2. The participant draws their copy of the cube using mouse, touchscreen, or stylus input.
3. If a time limit is set, a countdown is displayed and the task ends automatically when time runs out.
4. The participant clicks the button to submit their drawing and advance.

Data Output

Markers and Responses

The task records high-resolution timestamps in two separate collections:

Markers (stimulus_shown):

{
  "type": "stimulus_shown",
  "ts": "2024-01-01T00:00:01.000Z",
  "hr": 1234.56,
  "data": {
    "trial_index": 1
  }
}

Response Data:

{
  "type": "image/png",
  "size": 45231
}

Drawing Artifact

The participant's cube drawing is saved as a PNG image file (copy_of_cube_<index>.png). This image can be scored manually using established rubrics (e.g., MoCA cube scoring criteria).

Scoring Criteria

Traditional scoring assesses:

1. Parallelism: Opposite sides parallel
2. 3D Perspective: Front face and back face correctly positioned
3. Line Quality: Straight lines, clean connections
4. Overall Accuracy: Resemblance to target cube

Design Recommendations

• Reference Placement: Keep the reference cube visible throughout the drawing to allow continuous comparison.
• Time Limit: Two minutes is standard for screening; extend for populations with motor difficulties.
• Scoring: Use established scoring rubrics (e.g., MoCA cube scoring criteria) for consistent evaluation.
• Instructions: Tell participants to copy the cube as accurately as possible; emphasize that it should be three-dimensional.
• Input Devices: Stylus or touchscreen input is preferred for more natural drawing. Mouse drawing may reduce drawing quality.

Common Issues and Solutions

Issue	Solution
Participants draw a 2D square instead of a 3D cube	Ensure instructions emphasize copying the 3D cube exactly as shown
Drawing quality is poor with mouse input	Consider using stylus or touchscreen; adjust scoring expectations for mouse input
Time limit too short for older adults	Increase the time limit for clinical populations
Reference cube not visible	Verify Show Reference is enabled

References

• Nasreddine, Z. S., et al. (2005). The Montreal Cognitive Assessment, MoCA: A brief screening tool for mild cognitive impairment. Journal of the American Geriatrics Society, 53(4), 695-699.
• Trojano, L., & Gainotti, G. (2016). Drawing disorders in Alzheimer's disease and other forms of dementia. Journal of Alzheimer's Disease, 53(1), 31-52.

See Also

• Drawing Task - General drawing capability
• WCST - Executive function assessment