Is visual perception testing worth the time?

The Test of Visual Perception skills (TVPS) is a common part of a school-based occupational therapists evaluation process. Performance on this test has been used to infer visual processing problems. These “visual processing problems” are then thought to be related to letter reversals or reading problems. The good OT will be working to improve these visual perception skills. These therapists often get frustrated with a lack of progress with these visual perception skills and the lack of progress with the related academic problems.

So whats the best visual perception task?…

…is a very common question we answer frequently, but often not with the answer expected. Let us explain:

Vision can be described as a multi-step process. Step one is referred to as Visual Signal Acquisition. Here, visual information is collected by the eye. The accuracy of this visual information is dependent on things such as refractive state, binocular visuals skills and other cognitive factors such as attention and engagement with the test. When the information is not collected by the eye accurately, then the next step visual signal processing will suffer as the brain did not start with the correct information. The student fails the visual perception test and is perhaps labeled with “visual processing disorder” and in some school systems, referred to teachers of the visually impaired, who have little background to understand these problems when they find the child has no acuity problems.

What does the science say?

In a 2005 article in the American Journal of Occupational Therapy, the authors point out the high incidence of visual deficits in children with reading and learning problems. They further suggest the need for any child with difficulties in visual perception or visual motor integration be assessed for ocular motor and binocular vision problems(1).

An article in the Irish Journal of Occupational Therapy (2), authors found that only results on two of the seven areas of the assessment correlated to problems reported by teachers, further bringing into question the useful of the assessment. Interestingly, the areas that correlated, visual discrimination and visual memory, both rely upon and assume good visual signal acquisition. The article cites several studies showing a lack of correlation between the TVPS and other tests of visual perception such as the MVPT or DTVP.

Clinical Pearls

So when a therapist feels that a processing problem may be occurring, the first step should be a comprehensive eye exam to insure that the stimulus is being seen accurately. Also note the behavior of the student during the test: Are the engaged and attentive and giving their best effort?

References

(1) Goldstand, S., Koslowe, K. C., & Parush, S. (2005). Vision, Visual-Information Processing, and Academic Performance Among Seventh-Grade Schoolchildren: A More Significant Relationship Than We Thought? American Journal of Occupational Therapy, 59(4), 377-389. doi:10.5014/ajot.59.4.377

(2) Sullivan, C., Lynch, H., & Kirby, A. (2018). Does visual perceptual testing correlate with caregiver and teacher reported functional visual skill difficulties in school-aged children? Irish Journal of Occupational Therapy, 46(2), 89-105. doi:10.1108/ijot-03-2018-0005

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