For the stitching activity, the concept of doing an activity guides them through three stitches. The concept of a visual error is used to detect the front and back and the cross-in-back error. The twisted error is either not seen or is unsolvable.
Within the copying activity, they are able to keep track of alternating colors in the first row but cannot keep track of horizontal and vertical alterations of color which results in a striping pattern.
The placement activities let you observe their ability to match using one striking feature versus two striking features. The poor ability to use horizontal and vertical linear information can be seen by the poor orientation of the pieces placed in these activities as they cannot use the horizontal and vertical linear information simultaneously.
To Verify
If the person's medical condition is likely to cause changes in their ability to function, frequent verification of their score is required. See if they are matching to a sample on one linear plane. Check to see if they can follow a pattern on a string of beads or can copy a line of simple shapes.
To Rule Out
See if the person is able to use information from the next higher level. Can they match using two striking features simultaneously?