Dyslexia is a common learning difference primarily affecting reading. It is neurological in origin, stemming from brain differences. Dyslexia is not a reflection of intelligence or effort, but rather involves how the brain processes language. Individuals with dyslexia possess a range of cognitive abilities and can be highly intelligent.
How Words May Appear
Individuals with dyslexia often describe visual experiences when reading. These include letters appearing to move, jump, blur, or swap positions on the page. Some report that letters seem to crowd, making it difficult to distinguish individual characters.
Letters like ‘b’ and ‘d’ or ‘p’ and ‘q’ may be confused due to perceived reversals or inversions. Text might appear shimmery, doubled, or unstable, sometimes causing readers to skip words or lines. These visual phenomena are not universal to all individuals with dyslexia but are commonly reported perceptual challenges.
Beyond Visual Differences
While visual distortions can be part of the dyslexic experience, the core of dyslexia is a phonological processing difficulty. This involves challenges with the sound structure of language, how sounds are identified and manipulated. Difficulties often arise in sound-symbol mapping, connecting spoken sounds to their corresponding written letters.
Phonemic awareness, the ability to manipulate individual sounds (phonemes) in words, is often impaired. This can make tasks like blending sounds to form words or segmenting words into individual sounds challenging. Individuals with dyslexia may experience difficulties with rapid automatized naming (RAN), the quick naming of familiar visual stimuli like letters or numbers. Working memory, particularly verbal working memory, is often affected, making it harder to temporarily hold and process information needed for reading comprehension.
Neurobiological Basis
Research shows differences in brain activity and connectivity associated with dyslexia. Studies using functional magnetic resonance imaging (fMRI) show atypical activity in brain regions involved in language and reading. These areas are primarily located in the left hemisphere of the brain.
Regions implicated include the left temporo-parietal cortex, playing a role in phonological processing and sound-to-letter mapping. Reduced activation in this area is a consistent finding in individuals with dyslexia during reading tasks. The occipito-temporal cortex, including the visual word form area (VWFA), is also affected, impacting the automatic recognition of written words. These neurobiological differences contribute to challenges in acquiring fluent reading skills.
Variability and Everyday Impact
Dyslexia manifests as a spectrum, with varying experiences and severity among individuals. No two people with dyslexia will have identical profiles of strengths and challenges. The impact extends beyond reading, affecting other language-based tasks such as spelling and writing.
Daily life can also be affected broadly, including challenges with organization, time management, and navigating unfamiliar environments. Despite these difficulties, dyslexia does not indicate a lack of intelligence. Many individuals with dyslexia demonstrate strengths in areas like creative thinking, problem-solving, visual-spatial reasoning, and empathy.