Bells Test

Overview

Overview

A review of the Bells Test reported that the measure has excellent test-retest reliability than Line Bisection Test (Marsh & Kersel, 1993; Azouvi et al., 2002).

For the purposes of this review, we conducted a literature search to identify all relevant publications on the psychometric properties of the Bells Test.

Reliability

Internal consistency:
No studies have examined the internal consistency of the Bells Test.

Test-retest:
No studies have examined the test-retest reliability of the Bells Test.

Validity

Construct:
Known groups:
Gauthier et al. (1989) examined the Bells Test in 59 subjects, of which 20 were controls, 19 had right cerebral lesions and 20 had left cerebral lesions. A statistically significant difference in mean scores between the group with right cerebral lesions and the group with left cerebral lesions was observed.

Criterion:
Vanier et al. (1990) administered the Bells Test and the Albert’s Test to 40 neurologically healthy adults, and 47 patients with right brain stroke. It was found that 38.3% of patients were diagnosed with USN using the Bells Test (with a cutoff score of greater than or equal to 4), compared with only 10.6 % with the Albert’s Test (using a cutoff score greater than or equal to 2). The results of this study suggest that the Bells Test is more likely to identify the presence of neglect than the Albert’s Test in patients with stroke.

Ferber and Karnath (2001) examined the ability of various cancellation and line bisection tests to detect the presence of neglect in 35 patients with spatial neglect. The Bells Test detected a significantly higher percentage of omitted targets than the other tests (Line Bisection Test, and 3 cancellation tests: Letter Cancellation Test, Star Cancellation Test and Line Crossing Test). The Line Bisection Test missed 40% of patients with spatial neglect. The Letter Cancellation Test and the Bells Test missed only 6% of the cases.

Responsiveness

No studies have examined the responsiveness of the Bells Test.

References
  • Azouvi, P., Samuel, C., Louis-Dreyfus, A., et al. (2002). Sensitivity of clinical and behavioural tests of spatial neglect after right hemisphere stroke. J Neurol Neurosurg Psychiatry, 73, 160 -166.
  • Ferber, S., Karnath, H. O. (2001). How to assess spatial neglect–Line Bisection or Cancellation Tests? J Clin Expl Neuropsychol, 23, 599-607.
  • Gauthier, L., Dehaut, F., Joanette, Y. (1989). The Bells Test: a quantitative and qualitative test for visual neglect. Int J Clin Neuropsychol, 11, 49-54.
  • Làdavas, E. (1994). The role of visual attention in neglect: A dissociation between perceptual and directional motor neglect. Neuropsychological Rehabilitation, 4, 155-159.
  • Marsh, N. V., Kersel, D. A. (1993). Screening tests for visual neglect following stroke. Neuropsychological Rehabilitation, 3, 245-257.
  • Menon, A., Korner-Bitensky, N. (2004). Evaluating unilateral spatial neglect post stroke: Working your way through the maze of assessment choices. Topics in Stroke Rehabilitation, 11(3), 41-66.
  • Vanier, M., et al. (1994). Evaluation of left visuospatial neglect: norms and discrimination power of the two tests. Neuropsychologia, 4, 87-96.