Dr. Weston Johnson
The Reading Brain (Part 5): Dyslexia Subtypes and Reading Problems
Dyslexia: Reading Problems and Disorders
There are three common reading problems. These problems occur with word recognition, reading fluency, and reading comprehension. There are also three reading disorders based on a combination of reading problems. Dyslexia, the most well-known reading disorder, is a developmental disorder that includes problems with word recognition and reading fluency (and often spelling is an included problem). Hyperlexia, however, a different type of reading disorder that includes problems with reading comprehension (and extends to problems understanding what is spoken aloud or language comprehension). Alexia is a third type of reading disorder, but unlike dyslexia and hyperlexia, it is an acquired disorder that is caused by brain injury, damage, or trauma.
Dyslexia: Subtypes of Dyslexia
There are no official “subtypes of dyslexia” (The Understood Team, 2020). At this time, more research is needed, but what people are referring to as subtypes are different ways students can struggle with reading (The Understood Team, 2020). These become ways for parents and teachers to describe the different reading errors students are making. The purpose for exploring types of dyslexia is to better understand the causes and treatments of reading problems (The Understood Team, 2020), but their use should be limited until more research is conducted since they can be used to make faulty assumptions about why students with dyslexia struggle with reading.
The following are what are commonly referred to as the subtypes of dyslexia:
Phonological Dyslexia. Students with phonological processing challenges demonstrate difficulty with breaking down words and sounding them out. Another name for this subtype is dysphonetic dyslexia. The primary concern with this type is the accuracy of word recognition, but it will also affect overall automaticity of recognizing words. Student support for these challenges should include explicit instruction that provides direct presentations of developmentally appropriate learning objectives.
Surface Dyslexia. This type is often associated with rapid naming deficits demonstrate challenges with rapidly naming letters, numbers, and colors. Other names for surface dyslexia may include rapid naming dyslexia, visual dyslexia, and dyseidetic dyslexia. Students with surface dyslexia have difficulty with automatically recognizing whole words, even though they have proficient decoding skills. Their primary difficulty is recognizing words automatically (i.e., quickly and accurately). Student support for these challenges should include repeated and/or frequent practice or review of skills.
Double Deficit Dyslexia. This third type is a double deficit of both phonological processing challenges and automatic word recognition. Double deficit dyslexia is associated with the lowest reading ability when compared to the other two subtypes (Norton et al., 2014). Student support for these challenges should include both recommendations from the other types of dyslexia.
For now, while researchers haven’t confirmed different types of dyslexia, there are several ways to approach these reading problems. First, teachers can consider the instructional hierarchy stages: acquisition of skills and knowledge, fluent demonstration of skills and knowledge, generalization of skills and knowledge, and adaptation of skills and knowledge (Haring et al., 1978). Consideration of these stages allows teachers to plan instructional strategies to address needs and meet learning goals. For example, a student with dyslexia demonstrating insufficient accuracy with word recognition skills are at the acquisition stage, whereas a student who is accurate but not fluent is at the fluency stage. Each ability stage prescribes different instructional strategies and mastery criteria.
Second, teachers can consider the neural pathways in the reading brain. The phonological path is established through decoding whereas the lexical path requires repeated exposure for orthographic mapping and sight recognition of words. Each lends itself to different approaches for instruction. For example, a student struggling with decoding would benefit from strengthening skills related to the phonological path, whereas a student with decoding skills but struggling with sight word recognition would benefit from additional repetition of words to improve the lexical path.
Third, teachers can consider the specific needs of the students within the scope of developmental literacy. Students with dyslexia should have diagnostic assessments to determine their instructional needs with print concepts, phonological awareness, word recognition, reading fluency, and spelling. This is essential for providing a structured literacy program for our most struggling readers.
Text from aLEARNcoach LLC (www.alearncoach.com).