Sunnybrook Neglect Assessment Procedure (SNAP)

SNAP’s Evaluation Summary

  What does the tool measure? Hemispatial neglect
  What types of clients can the tool be used for? Patients in the acute phase of stroke recovery.
  What ICF domain is measured? Impairment
  Is this a screening or assessment tool? Screening
Time to administer Not specified.
  Versions There is one version of the SNAP.
Languages English.
Measurement Properties

Internal Consistency:
One study reported moderate to excellent correlations between subtests and the total score.

Test-retest reliability:
No studies have reported on test-retest reliability among patients with stroke.

Intra-rater / inter-rater reliability:
One study reported adequate to excellent correlations for subtests and the total score.


Construct validity:
One study reported a moderate correlation among SNAP subtests.
Two studies have conducted factor analysis and found that all subtests loaded on one factor that accounted for 69-72% of the variance.

Convergent/discriminant validity:
One study reported adequate correlations with the visual search board (VSB) visual search task.
One study reported a significant correlation between neglect measured by the SNAP and parietal damage.
One study reported an excellent correlation between the SNAP and a measure of generalized attentional capacity (digit span forward minus digit span backward).

Known groups validity:
One study reported significant differences in performance on the SNAP according to side of lesion.

Criterion validity:
Concurrent validity:
No studies have reported on concurrent validity of the SNAP among patients with stroke.

Predictive validity:
One study reported that the SNAP significantly predicted neglect (present/absent) on the visual search board (VSB) visual search task.

  Floor/Ceiling Effects No studies have reported on floor/ceiling effects among patients with stroke.
  Sensitivity/ Specificity One study reported 68% sensitivity and 76% specificity.
Two studies reported that the shape cancellation task was the most sensitive subtest; a third study reported that the line bisection task was the most sensitive subtest.  
One study reported that the drawing/copying subtests showed highest specificity.
  Does the tool detect change in patients? The tool does not detect or measure change but it can be used to monitor change in neglect over time.
  Acceptability The SNAP is simple to administer and can be used at the individual’s bedside.
Feasibility The SNAP is portable, quick to administer and requires minimal equipment.
How to obtain the tool? The SNAP administration and scoring manual and test booklet can be accessed here