A circle-monitor for computerised assessment of visual neglect in peripersonal space

Abstract

Current assessment of visual neglect involves paper-and-pencil tests or computer-based tasks. Both have been criticised because of their lack of ecological validity as target stimuli can only be presented in a restricted visual range. This study examined the user-friendliness and diagnostic strength of a new "Circle-Monitor" (CM), which enlarges the range of the peripersonal space, in comparison to a standard paper-and-pencil test (Neglect-Test, NET).

Methods: Ten stroke patients with neglect and ten age-matched healthy controls were examined by the NET and the CM test comprising of four subtests (Star Cancellation, Line Bisection, Dice Task, and Puzzle Test).

Results: The acceptance of the CM in elderly controls and neglect patients was high. Participants rated the examination by CM as clear, safe and more enjoyable than NET. Healthy controls performed at ceiling on all subtests, without any systematic differences between the visual fields. Both NET and CM revealed significant differences between controls and patients in Line Bisection, Star Cancellation and visuo-constructive tasks (NET: Figure Copying, CM: Puzzle Test). Discriminant analyses revealed cross-validated assignment of patients and controls to groups was more precise when based on the CM (hit rate 90%) as compared to the NET (hit rate 70%).

Conclusion: The CM proved to be a sensitive novel tool to diagnose visual neglect symptoms quickly and accurately with superior diagnostic validity compared to a standard neglect test while being well accepted by patients. Due to its upgradable functions the system may also be a valuable tool not only to test for non-visual neglect symptoms, but also to provide treatment and assess its outcome.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Schematical drawing of the CM.

Figure 2. Layout of Dice Task (a) and Puzzle Test (b).

In the Dice Task, patients were asked to use all dots and create a dice pattern. In the Puzzle Test, patients were required to select the correct pieces (from the left and right screen) to create the puzzle in the middle screen.

Figure 3. Lesion overlay plot (N = 9).

Lesion overlap was highest in the right posterior superior temporal gyrus and insula as indicated by reddish colours, N: # patients with lesion, L: left, R: right, position of slices (MNI coordinates x/y/z): 54/-26/12.

Figure 4. Lesion patterns of individual patients.

Patient numbers correspond to patient IDs in Table 1 (patients #2-10). No MRI was available for patient #1. Right side of the brain corresponds to right hemisphere.

Figure 5. Star Cancellation Test: Percentage of detected stars, split into test-system, experimental group and visual field.

The figure shows means and standard errors. Best possible performance (100%) in NET was 27 stars, in CM 20 stars per side. CM: Circle-Monitor, NET: Neglect-Test.

Figure 6. Results in visuo-constructive tests separated for patients and controls, left and right visual field.

Dice Task (a) and Puzzle Test (b) are CM subtests, Copy Task (c) and Clock Drawing Test (d) are NET subtests. Diagrams show means and standard errors, L: left, R: right. Maximum achievable score per side: Puzzle: 10, Copy Task: 7, Clock Drawing Test: 2.