I am a special education teacher. I wanted to ask which assessment(s) you would recommend to diagnose dyslexia if I were to purchase just one or two assessments. Let's say that I already know that the student has an average IQ, so I don't need an aptitude test.

Dr. Pierson's Response: 

That is a tough question because I really don't think 1-2 tests will be adequate to diagnose dyslexia. You could probably get away with 1 or 2 tests to screen, but diagnosis requires looking at a number of areas and triangulating the data across measures.

For example, I just evaluated a 6-year-old student today and used 10 measures to get the data to make the diagnosis of dyslexia. The measures covered receptive vocabulary/language comprehension, expressive vocabulary (because he demonstrated word retrieval challenges), verbal expression (to compare with his writing); phonological awareness (on which he scored in the average range), phonological memory, rapid automatic naming; decoding real/nonsense single words under time; reading passages to assess reading rate, reading accuracy, reading fluency, and reading comprehension; spelling (on which he scored average despite numerous phonological and orthographic errors); working memory; and writing.

If he would have been tested with 1-2 measures, e.g., say I started with the phonological processing and spelling measures and stopped there, the dyslexia would have been missed, particularly if I didn't know how to evaluate the spelling errors (beyond just the test score). I could tell from those errors that he was having difficulty at the phonological level, which meant delving deeper to find out more.

So, knowing the above, if the district will only let you purchase a few tests -- the Comprehensive Test of Phonological Processing -2 (CTOPP-2) is currently the best we have for evaluating phonological processing skills, which must be assessed because these are the challenges that underlie the struggles with reading and spelling. But, one weakness of the CTOPP-2, and it is a significant one, is that the phonological awareness tasks are not timed. It has been shown in the literature that struggles with speed of accessing phonological information can impact reading and spelling skills (Kilpatrick, 2015). And, these challenges can persist into adulthood. So, a student can really struggle to answer the prompts (i.e., take forever, evidence many revisions, count on his fingers) and eventually get to the correct answer. That response is scored exactly the same as a student who immediately and easily responds -- as correct. These two students are NOT the same. That is why it is important to analyze the data and test performance behavior (on all measures, really).

The other measure that we find informative is the Test of Word Reading Efficiency - 2 (TOWRE-2). The TOWRE-2 is very quick to administer. The student reads real and nonsense words under a 45-second time constraint. As mentioned above, the literature is clear that while people with dyslexia learn to read, they tend to remain slow, so, again, timed measures are very important. And, again, analysis of the errors is very important. Many times students can read the real words that they've been taught and are just slow (that’s informative -- the intervention is working, for example), but then when pressed to decode nonsense words (i.e., use what they know without the help of their stronger spoken language skills), they struggle.

Another test I’d recommend is the Test of Written Spelling - 5 (TWS-5), but this test is most informative when an analysis is conducted to determine whether the errors are phonological versus orthographic in nature (or both).

The Gray Oral Reading Test - 5 (GORT-5) (not 4!) is a good measure to look at reading skills at the passage level.

At 3LI, my private clinical practice, we use the Oral-Written Language Scales -- II (OWLS-II) for written expression. A caveat, though -- my partner at 3LI, Dr. Lauren Katz, and I find that the scores on this measure tend to over-inflate the writing skills of the clients whom we have evaluated. Again, it is important to go beyond the test score and interpret the data when making a diagnosis.

I suggest getting a copy of David Kilpatrick's book Essentials of Assessing, Preventing, and Overcoming Reading Difficulties (2015). It is very well written and will answer many questions. The other book I recommend is Sally Shaywitz's Overcoming Dyslexia: A New and Complete Science-Based Program for Reading Problems at Any Level. Despite its 2003 publication date (although the word is a new edition will be out in 2020), it continues to be an excellent resource. Dr. Shaywitz wrote the book for parents, so it is extra-reader friendly. The only thing is -- she does not use the term structured literacy, which is the term the International Dyslexia Association (IDA) coined in 2014 to describe the intervention for remediating reading disorder, including dyslexia. The intervention she describes is structured literacy.

In sum, you can see it's challenging to triangulate all the data from a comprehensive assessment in order to make a diagnosis of dyslexia. I think you could determine which measures the district currently has and then fill in with the new tests in order to cover all of the pieces necessary to make the diagnosis of dyslexia. For example, your speech-language pathologist will have some of the measures for spoken language, the learning disabilities consultant will have reading measures. I think Kilpatrick's book will be of great help as well. Last, diagnosing dyslexia is both a science and an art. We find it helpful at 3LI to have another diagnostician with whom you can discuss the data, especially when the waters are murky, as can frequently be the case. Perhaps you can team up with another professional in the district. I hope this points you in the right direction.