Sunnybrook Neglect Assessment Procedure (SNAP)

Purpose of the measure

The Sunnybrook Neglect Assessment Procedure (SNAP) is a test battery for bedside screening of neglect. It is designed to assess neglect in patients with acute stroke and to monitor recovery of neglect at later stages of stroke recovery.

Available versions

There is one version of the SNAP.

Features of the measure

Items:
The SNAP is comprised of five paper-and-pencil items that are familiar measures of neglect. The items are administered to the patient in the following order:

  1. Spontaneous drawing of clock and daisy
  2. Line cancellation task
  3. Line bisection task
  4. Copying of clock and daisy
  5. Shape cancellation

Description of tasks:
A1. Drawing task
The patient is asked to draw a clock face and a daisy on a blank piece of paper.

B. Line Cancellation Task
The patient is instructed to cross out all lines on a page.

C. Line Bisection Task
The patient is instructed to draw a mark on a line in order to bisect the line in half. This task is completed using 15cm and 20cm lines.

A2. Copying Tasks
The patient is asked to copy a picture of a clock and a daisy.
Note: The assessor does not identify that the pictures are a clock and a daisy.

D. Shape Cancellation Task
The patient is required to circle all the targets on a page.
Note: This is a timed task. The patient is given a different color pencil after every tenth target is circled, to determine the search pattern.

Scoring and score interpretation:
The scoring of the different SNAP subtests is based on omissions made on the contralateral side of the brain lesion. Left-side omissions are scored in patients in right hemisphere stroke and right-side omissions are scored in left hemisphere stroke.

A. Copying and drawing tasks
Drawings with a significant omission of details on the contralateral side are scored as having neglect.

B. Line Cancellation
Each omitted line on the contralateral side of the page is scored as neglect.

C. Line Bisection 
The score for this task is based on the mean percent deviation of the patient’s mark from the true midpoint. Percent deviation and average deviation is calculated for the four lines of the task, according to the formula stipulated in the SNAP manual.

D.Shape cancellation task
All targets omitted on the contralateral side of the page are counted.

Total score interpretation:
Scores are calculated using the SNAP scoring manual. The patient is awarded a score for each subtest, resulting in a total score out of 100.

Leibovitch et al. (2012) recommended classifying severity of neglect according to performance on the SNAP as follows:

SNAP Score

Classification of Performance

0-5

Normal Performance

6-40

Mild Neglect

41-100

Severe Neglect

Please see the SNAP Administration and Scoring Manual for more details on scoring (Black et al., 2016).

What to consider before beginning:
SNAP test items should always be placed in the individual’s midline.

Time:
Time taken to administer the assessment has not been specified. Time will vary according to the patient’s attention and severity of neglect.

Training:
Training requirements have not been specified.

Subscales:
None.

Equipment: 

  • SNAP assessment package
  • Two blank sheets of paper
  • Coloured pens/pencils
  • Stopwatch
Alternative forms of the SNAP

The original version of the Sunnybrook Neglect Assessment contained additional drawing tasks, a paragraph reading task, a writing task and additional visual search tasks. The four items that comprise the SNAP were deemed to be complementary and not redundant, so the additional items were eliminated (Leibovitch et al., 2012).

Client suitability

Can be used with:
Patients with stroke.

Should not be used with:
Not specified.

In what languages is the measure available?
English.