Deep dyslexia
Numerous models and hypotheses have been proposed in attempt to explain the broad range of symptoms experienced by deep dyslexics, but a definite consensus has yet to be reached.
[6][9] This has resulted in deep dyslexia being considered a symptom-complex and has led to much research into why this variety of symptoms may co-occur in so many patients.
[11] In an attempt to explain this relationship, researchers have developed a variable to link the mental imagery created by a word and the ease of reading it.
[11] This variable, ease of predication, is a rating of how easy it is to come up with simple factual statements or attributes of a word.
[11][13] For example, when presented with the word "dog", an individual may come up with statements, or predicates, such as "has four legs", "is an animal", or "barks and wags its tail".
[14] These theories have resulted in several models designed to conceptualize the symptom-complex found in deep dyslexics.
These models are not ordered chronologically, but rather follow a general increasing trend of presence in the field of knowledge regarding deep dyslexics.
Models and hypothesis toward the end of the list are more heavily debated and thus typically have a greater wealth of knowledge surrounding their topic.
She placed great emphasis on the order in which reading symptoms emerged (poor nonword reading first, then visual errors, then noun > functor, then noun > verb, concrete > abstract, and finally, semantic errors) and suggested that the continuum hypothesis was supported by this pattern of symptoms.
[2][3] This hypothesis explains the broad symptom-complex of deep dyslexics without resorting to a multiple loci damage approach as seen in other models.
[2][3] Plaut and Shallice have hypothesized that units in the brain interact in such a way that semantic features form stable attractors in the space of all possible representations of words.
When this happens, you may now have the same distorted starting pattern that will end up in a neighboring basin, which is a semantically related area, but not the correct one, and this would account for deep dyslexic patients to incorrectly identify "river" as "ocean".
[21] Researchers believe that "failure of inhibition" has no effect on implicit processing, but instead is the cause of impairments in the explicit task of speech production.
[21] Researchers have studied the dissociation of implicit and explicit processes to thus unravel the underlying deficiencies in deep dyslexia.
Studies in support of "failure of inhibition" show intact implicit processing of deep dyslexics.
Thus, some researchers believe that the impairments present in deep dyslexics are only in explicit phonological output (i.e., reading aloud).
[21] This is supported by the fact that deep dyslexia is often present in patients with production errors resulting from Expressive aphasia.
It proposes that the occurrence of semantic errors alongside an inability to read non-words aloud must be due to multiple loci of damage within this dual-route model.
The nonlexical module is comparable to the phonological route and uses knowledge of spelling and graphemes to create phonemes to name words and nonwords.
