Deep dyslexia

A type of acquired dyslexia characterized by semantic errors and difficulty with non-words

Deep dyslexia is a form of acquired dyslexia that occurs following brain damage, typically to the left hemisphere, and is characterized by specific reading impairments. Individuals with deep dyslexia often make semantic errors when reading aloud, such as saying "dog" when the word "cat" is written. They also have difficulty reading non-words and exhibit a range of other symptoms that distinguish it from other types of dyslexia.

Characteristics

Deep dyslexia is marked by several distinctive features:

• Semantic errors: Readers may substitute a word with another that is semantically related, such as reading "ship" as "boat."
• Visual errors: Mistakes may occur where a word is read as another word that looks similar, such as reading "house" as "horse."
• Derivational errors: Errors in reading words with affixes, such as reading "happiness" as "happy."
• Difficulty with non-words: Individuals with deep dyslexia struggle to read non-words or pseudowords, which are not stored in the mental lexicon.
• Concrete words are easier: Words that are concrete and imageable are easier to read than abstract words.

Neurological Basis

Deep dyslexia is associated with damage to the left hemisphere of the brain, particularly areas involved in language processing. This damage often results from a stroke, traumatic brain injury, or other forms of brain injury.

Brain trauma CT scan

The condition is thought to arise from disruptions in the normal reading pathways. The dual-route hypothesis to reading aloud suggests that there are two main pathways for reading: the lexical route, which involves recognizing whole words, and the non-lexical route, which involves sounding out words. In deep dyslexia, the non-lexical route is impaired, forcing reliance on the lexical route, which can lead to semantic errors.

Theoretical Models

Several models have been proposed to explain the reading difficulties observed in deep dyslexia:

• Dual-route model: This model posits that reading involves two separate pathways, and damage to the non-lexical route results in the symptoms of deep dyslexia.

Dual route model and deep dyslexia diagram

• Connectionist models: These models suggest that reading is a distributed process involving networks of neurons. Damage to these networks can lead to the symptoms of deep dyslexia.

Connectionist model of deep dyslexia

Diagnosis and Assessment

Diagnosis of deep dyslexia involves a comprehensive assessment of reading abilities, often conducted by a neuropsychologist or speech-language pathologist. Tests may include reading aloud, comprehension tasks, and assessments of phonological processing.

Treatment and Management

Treatment for deep dyslexia typically involves speech and language therapy focused on improving reading skills. Strategies may include:

• Phonological training: Exercises to improve phonological awareness and decoding skills.
• Semantic therapy: Activities to strengthen the connection between words and their meanings.
• Use of technology: Assistive devices and software to support reading and communication.

Related Pages

• Dyslexia
• Acquired dyslexia
• Semantic memory
• Phonological dyslexia

Hear Read Brain

See Also

• Aphasia
• Cognitive neuropsychology
• Language processing in the brain