The Bells Test is a cancellation test that allows for a quantitative and qualitative assessment of visual neglect in the near extrapersonal space.
The Bells Test was developed by Gauthier, Dehaut, and Joanette in 1989.
There are no actual items to the Bells Test.
In the Bells Test, the patient is asked to circle with a pencil all 35 bells embedded within 280 distractors (houses, horses, etc.) on an 11 x 8.5 – inch page (Figure 1). All drawings are black. The page is placed at the patient’s midline.
Figure 1. Bells Test
The objects are presented in an apparently random order, but are actually equally distributed in 7 columns containing 5 targets and 40 distractors each. There is a black dot on the bottom of the page to indicate where the page should be placed in relation to the patient’s midsaggital plane. Of the 7 columns, 3 are on the left side of the sheet, 1 is in the middle, and 3 are on the right. Therefore, if the patient omits to circle bells in the last column on the left, we can estimate their neglect is mild. However, omissions in the more centered columns can suggest a greater neglect of the left side of space.
The examiner is seated facing the patient. First a demonstration sheet is presented to the patient. This sheet contains an oversized version of each of the distractors and one circled bell. The patient is asked to name the images indicated by the examiner in order to ensure proper object recognition. If the patient experiences language difficulties or if the examiner suspects comprehension problems, the patient can instead place a card representing that object over the actual image.
The examiner gives the following instructions: “Your task will consist of circling with the pencil all the bells that you will find on the sheet that I will place in front of you without losing time. You will start when I say “go” and stop when you feel you have circled all the bells. I will also ask you to avoid moving or bending your trunk if possible.” If a comprehension problem is present, the examiner has to demonstrate the task.
The test is then placed in front of the patient with the black dot (see arrow on Figure 1) on the subject’s side, centered on his midsagittal plane (divides the body into right and left halves). The test sheet is given after the instructions.
The examiner holds the scoring sheet (Figure 2) away from the patient’s view, making sure the middle dot is towards the patient. This upside-down position will make scoring easier for the examiner. After the patient begins the test, the examiner records the order of the bells circled by the patient by numbering the order on his/her scoring sheet (e.g. 1, 2, 3,…). If the patient circles another image (an image that is not a bell), the examiner indicates on his/her scoring sheet the appropriate number and the approximate location. The subsequent bell receives the next number.
Figure 2. Examiner scoring sheet.
If the patient stops before all the bells are circled, the examiner gives only one warning by saying “are you sure all the bells are now circled? Verify again.” After that, the order of numbering continues, but the numbers are circled or underlined. The task is completed when the patient stops his/her activity.
The total number of circled bells is recorded as well as the time taken to complete. The maximum score is 35. An omission of 6 or more bells on the right or left half of the page indicates USN. Judging by the spatial distribution of the omitted targets, the evaluator can then determine the severity of the visual neglect and the hemispace affected (i.e. left or right).
The sequence by which the patient proceeds during the scanning task can be determined by connecting the bells of the scoring sheet according to the order of the numbering.
Less than 5 minutes.
None typically reported.
The test paper (8.5″x11″ page with 35 bells embedded within 280 distractors).
Can be used with:
Patients with stroke.
Patients must be able to hold a pencil to complete the test (the presence of apraxia may impair this ability).
Patients must be able to visually discriminate between distractor items, such as the images of houses and horses, and the bells that are to be cancelled.
Should not be used with:
As with other cancellation tests, the Bells Test cannot be used to differentiate between sensory neglect and motor neglect because it requires both visual search and manual exploration (LÀdavas, 1994).
The Bells Test cannot be completed by proxy.