Wikipedia:WikiProject Dyslexia/Alexia resources

Alexia is a very complex topic. There are many forms of grouping, and many subtypes in each grouping. On going research continues to provide a greater understanding of the neurological issues which can cause Alexia, which can result in new subtypes, new Theoretical Models of Reading, and even new classifications.

So we need research resources to provide both in depth information and citations, for the what is accepted at this point in time and at all times in the future.

The starting place original Neuroanatomical classifications, To help define the various sub various sub variation which clinicians and researcher were seeing, the Psycholinguistic or cognitive Models of Reading were developed to provide better perspective of Alexia. There are two Psycholinguistic Alexia groups, the Central Alexia group and the Peripheral Alexia group, each of which have their own sub types of Alexia (see below)

Neuroanatomical classifications

Alexia with Agraphia

which is now known as Central Alexia or Central Dyslexia and as a result Psycholinguistic sub classifactions currently has 4 subtypes (see below)

From Aphasia, Alexia, and Oral Reading (2004)A Review by L. R. Cherney

Alexia with Agraphia (Parietal-temporal alexia) is characterized by impairments of both reading and writing, with the writing impairment usually equal in severity to the alexia. Patients display difficulty in comprehending written material that is read silently as well as in reading out loud. Reading of letters and words is impaired, and this difficulty extends to comprehension of numbers and musical notations. The problem with letter identification is not restricted to the visual modality; patients also have problems recognizing words when they are spelled aloud. Parietal-temporal alexia is often associated with a fluent paraphasic aphasia.

Alexia without Agraphia

• Referred to as Pure Alexia
• Also known as Global dyslexia, letter-by-letter (LBL) dyslexia, spelling dyslexia, word-blindness, word-form dyslexia.

From Aphasia, Alexia, and Oral Reading (2004)A Review by L. R. Cherney

Alexia without agraphia (occipital alexia) is easily recognized because it is characterized by a disturbance of reading contrasted with relatively preserved writing skills. Patients typically cannot read what they have just finished writing. The difficulty with letter and word recognition is specific to the visual modality, and patients can spell out aloud and recognize words spelled to them by the examiner. Therefore, alexia without agraphia is also called pure alexia, pure word blindness, or agnosic alexia. Letter naming, although initially slow, improves with practice, and the patients often learn to read the individual letters of the word aloud and then decipher the words from their oral spelling.

Frontal Alexia

• also known as the "Third Alexia"

From Aphasia, Alexia, and Oral Reading (2004)A Review by L. R. Cherney

In patients with frontal alexia, reading comprehension is typically limited to a few single words, usually content words. Reading comprehension of function words such as prepositions and pronouns is impaired. In contrast to their ability to recognize some words, patients are unable to read the individual letters of the word. Spelling words out loud and comprehension of words that are spelled aloud is also poor. A severe agraphia accompanies the alexia, with writing characterized by poorly formed letters, omission of letters, and agrammatic sentences. Frontal alexia is typically associated with a nonfluent aphasia

Spatial Alexia

The most recent subtype to be added to the Neuroanatomical group.

Theoretical Models of Reading

There are quite a few models all of which are modified as research increases our understanding of the cognitive processes and how they interact when we perform the task of reading, or not in the case of Alexics, who prior to their form of brain damage were able to read.

A basic diagram which outlines most of the Psycholinguistic Model of normal reading

Diagram Outlining a Model of the Normal Reading Process

		Vision
		↓
↓	←—	Perceptual Analysis
↓		↓
Letter Sound Converter		Visual Word Store	—→	Semantic Processor
↓		↓		↓
→	—→	Phonological Processor	←—	←
		↓
		Speech

Psycholinguistic - Central alexias

• Also known as Alexia with an Aphasia
• 4 subtypes, the researchers prefer to call them dyslexias

Deep dyslexia

Deep dyslexia

Diagram Outlining a Model of the Deep Dyslexia Reading Process

		Vision
		↓
		Perceptual Analysis	—→	↓
				↓
				Semantic Processor
				↓
		Phonological Processor	←—	←
		↓
		Speech

Phonological dyslexia

Diagram Outlining a Model of the Phonological Dyslexia Reading Process

		Vision
		↓
		Perceptual Analysis
		↓
		Visual Word Store	—→	Semantic Processor
		↓		↓
		Phonological Processor	←—	←
		↓
		Speech

Semantic dyslexia

Semantic dyslexia

Diagram Outlining a Model of the Semantic Dyslexia Reading Process

		Vision
		↓
↓	←—	Perceptual Analysis
↓		↓
Letter Sound Converter		Visual Word Store
↓		↓
→	—→	Phonological Processor
		↓
		Speech

Surface dyslexia

Diagram Outlining a Model of the Surface Dyslexia Reading Process

		Vision
		↓
↓	←—	Perceptual Analysis
↓
Letter Sound Converter
↓
→	—→	Phonological Processor
		↓
		Speech

Psycholinguistic - peripheral alexias

Pure alexia

Pure alexia

Hemianopia alexia

which was until recently included as Attentional alexia.

Clinical causal and related conditions

Aphasia

• main page article aphasia

Fluent aphasias

• Anomic aphasia (anomia)
• Receptive aphasia (also known as Wernicke’s aphasia, fluent aphasia, or sensory aphasia)

Nonfluent aphasias

• Expressive aphasia (also known as Broca's aphasia agrammatic aphasia)

"Pure" aphasias

• Agraphia
• Pure alexia
• Pure word deafness

Dementia

main page article dementia

Stroke

• main page article stroke
• Ischemic stroke
• Ischemia
• Transient ischemic attack

Resources

The understanding of Alexia, acquired dyslexia, has radically progressed from the late 19th Century. It would probably be best to list resources such as books, research papers, etc. in chronological order by decade so that sources can be compared using the research based understanding of that particular time frame.

1960s

• Geschwind N (June 1965). "Disconnexion syndromes in animals and man. I". Brain. 88 (2): 237–94. PMID 5318481.
• Geschwind N (September 1965). "Disconnexion syndromes in animals and man. II". Brain. 88 (3): 585–644. PMID 5318824.

1970s

• Benson DF (June 1977). "The third alexia". Arch. Neurol. 34 (6): 327–31. PMID 860935.
• Marshall, John; Freda Newcombe (September 1973). "Patterns of paralexia: A psycholinguistic approach". Journal of Psycholinguistic Research. 2 (3): 175–199. doi:10.1007/BF01067101.

1980s

• Coltheart M (June 1982). "The psycholinguistic analysis of acquired dyslexias: some illustrations". Philos. Trans. R. Soc. Lond., B, Biol. Sci. 298 (1089): 151–64. PMID 6125968.
• Kirshner HS, Webb WG (August 1982). "Alexia and agraphia in Wernicke's aphasia". J. Neurol. Neurosurg. Psychiatr. 45 (8): 719–24. PMC 1083163. PMID 7130996.
• Siegel, Linda S. (April 1985). "Deep dyslexia and developmental dyslexia: A parallel". Language Sciences. 7 (1): 53–71. doi:10.1016/S0388-0001(85)80012-7.
• Warrington EK, Shallice T (March 1980). "Word-form dyslexia". Brain. 103 (1): 99–112. doi:10.1093/brain/103.1.99. PMID 6244876.

1990s

• Démonet JF, Chollet F, Ramsay S, et al. (December 1992). "The anatomy of phonological and semantic processing in normal subjects". Brain. 115 ( Pt 6): 1753–68. PMID 1486459.
• Friedman, Rhonda B.; Susan R. Robinson (1991-10-06). "Whole-word training therapy in a stable surface alexic patient: It works". Journal of Aphasiology. 5 (6): 521–527. doi:10.1080/02687039108248557.
• Mesulam MM (June 1998). "From sensation to cognition". Brain. 121 ( Pt 6): 1013–52. PMID 9648540.
• Wilson, Barbara A. (1994-06-03). "Syndromes of acquired dyslexia and patterns of recovery: A 6-to 10-year follow-up study of seven brain-injured people". Journal of Clinical and Experimental Neuropsychology. 16 (3): 354–371. doi:10.1080/01688639408402646.

2000s

• Cherney LR (2004). "Aphasia, alexia, and oral reading". Top Stroke Rehabil. 11 (1): 22–36. PMID 14872397.
• Cohen L, Martinaud O, Lemer C, et al. (December 2003). "Visual word recognition in the left and right hemispheres: anatomical and functional correlates of peripheral alexias". Cereb. Cortex. 13 (12): 1313–33. PMID 14615297.
• Démonet JF, Thierry G, Cardebat D (January 2005). "Renewal of the neurophysiology of language: functional neuroimaging". Physiol. Rev. 85 (1): 49–95. doi:10.1152/physrev.00049.2003. PMID 15618478.
• Fushimi T, Komori K, Ikeda M, Lambon Ralph MA, Patterson K (March 2009). "The association between semantic dementia and surface dyslexia in Japanese". Neuropsychologia. 47 (4): 1061–8. doi:10.1016/j.neuropsychologia.2008.12.030. PMID 19162051.
• Wilson SM, Brambati SM, Henry RG, et al. (January 2009). "The neural basis of surface dyslexia in semantic dementia". Brain. 132 (Pt 1): 71–86. doi:10.1093/brain/awn300. PMC 2638692. PMID 19022856.

2010s

Medlink - Alexia (a summary)