Diagnosing Dyslexia

Diagnosing Dyslexia

Early Screening

Children who will develop dyslexia can often be identified even before they learn to read.  One common method for identifying children who are at risk for developing dyslexia is to administer a battery of tests that measure letter identification ability and phonological processing ability.  The letter identification test measures whether or not the child can accurately identify the letters of the alphabet while phonological processing tests measure things like the ability to identify two words that rhyme or two words that start with the same sound, or at a more complex level to tell an examiner what a word would sound like if a letter was deleted (what would cat sound like if you took away the c).  One of the Assessment Modules contained the In Reading Success Lab software products contains tasks designed to identify children in kindergarten and grade 1 who may develop reading problems.
> More information about the K-1 Assessment Module

One difficulty with the Early Screening is that children who have had very poor early exposure to written material also do not do well on letter identification tasks and phonological processing tasks.  This means that early screening alone cannot distinguish between a child who performs poorly on the tasks because they are dyslexic, and a child who performs poorly on the tasks because no one has ever taught them the alphabet and the sounds that letters make.

The Discrepancy Method

Dyslexia in older children has traditionally been identified by administering tests that measure intellectual ability and tests that measure skills related to reading.  The traditional legal definition of dyslexia (often called specific reading disability) is that the reader has average or above average intellectual ability and reading ability that is well below intellectual ability, and that there are no extenuating reasons (e.g., English is the 2nd language) for the gap.  In short, that there is a large discrepancy between performance on intellectual ability tests and performance on reading tests.

Response to Intervention

A more modern method of identifying dyslexia is to use what is called the “response to intervention method.”  This procedure suggests that a child who is having difficulty in learning to read should be exposed to one or more “best practice” methods of reading instruction.  If the child still his having difficulty reading after exposure to best practice methods, then the child is likely to be dyslexic.  This approach leads to another question though.  If you try “best practice” methods of reading instruction and the child still can’t read, what do you do?  The intervention techniques contained in the Reading Success Lab Skill Builders were designed to provide an answer to this question.  Our Skill Builders work when other best practice methods don’t work
> More information about Skill Builders

Cognitive Profile Analysis

The diagnostic procedure used in the Reading Success Lab Assessment Software is called cognitive profile analysis.  This method is based on the premise that categories of readers will have different profiles of performance when performing reading tasks where both the speed and accuracy of performance is measured.  For example, good readers should display a different pattern than poor readers, and poor readers should be different than dyslexic readers.  Research has shown, in fact, that the Reading Success Lab Assessment Module can differentiate between good readers, average readers, poor readers, dyslexic readers, individuals with global learning difficulties (e.g., mildly retarded readers), and readers who are likely to have attentional disorders.
> Examples of the cognitive profiles for a poor reader and a dyslexic reader on the Dyslexia Overview Page

fMRI Analysis

Functional magnetic resonance imaging (fMRI) is a medical procedure that shows what parts of the brain become active when an individual reads.  Research has indicated that readers with dyslexia have distinctly different activation patterns than normal readers.  The procedure probably provides a very reliable way of identifying dyslexic readers, but there is not enough research to be certain of this.  In addition, the fMRI procedure is very expensive and for now at least is strictly a research tool and not a diagnostic procedure.