Alexia

Front 1

Name the three primary alexic syndromes and the location of lesions.

Back 1

1. Central Alexia (alexia with agraphia) usually due to inferior parietal lobule injury in language-dominant hemisphere (following MCA infarct). Also seen in hand ipsilateral to language-dominant hemisphere following lesion in CC (due to disconnect between language and motor areas). Also associated with severe confusion
2. Posterior Alexia (alexia without agraphia) Pathology in PCA leading to infarct in posterior occipital area including splenium of CC (spares angular gyrus). Disconnects visual information from language cortex.
3. Anterior alexia: pathology in left frontal area

Front 2

What symtoms are associated with Central Alexia?

Back 2

1. Inability to read or write
2. Preserved ability to copy writing without comprehension
3. loss of ability to name letters, comprehend spelled words, read out loud
4. often associated with aphasia
5. compoents of Gerstmann's syndrome may be present
6. may include hemisensory loss and/or right homonymous visual field deficit
AKA: alexia with agraphia, semantic alexia, parito-temporal alexia, total (literal and verbal) alexia, letter and word blindness, surface alexia

Front 3

What symptoms are associated with Posterior Alexia?

Back 3

1. Cannot read but are able to write (with practice may be able to read letters out loud, then can spell words out loud and recognize them auditorally)
2. cannot comprehend what they have written
3. writing is easier than copying
4. Often with right homonymous hemianopia
5. often unable to name colors
AKA: alexia without agraphia, pure word blindness, verbal alexia, visual alexia, pure alexia, occipital alexia, associative alexia

Front 4

What symptoms are associated with Anterior Alexia?

Back 4

1. Difficulty naming individual letters of alphabet but can recognize some written words
2. severe agraphia including inability to copy
3. can comprehend some spelled words but poor at spelling aloud
4. recognize some semantically meaningful words but not gramatically significant function words (known as agrammatism of written language)
5. right hemiplegia
6. nonfluent aphasia
7. may include unilateral sensory/visual-field neglect
AKA: literal alexia, letter blindness

Front 5

Which alexia syndrome is assocaited with Gerstman syndrome?

Back 5

Central alexia

Front 6

Which alexia syndrome is associated with motor loss?

Back 6

Central and anterior. Central associated wtih mild paresis and anterior alexia with hemiplegia.

Front 7

How is letter naming related to alexia syndromes?

Back 7

Central and anterior alexia have severe letter anomia
Posterior alexia: letter naming adequate

Front 8

What alexia syndrome(s) is associated with intact comprehension of spelled words and ability to spell aloud?

Back 8

Posterior alexia.
Central alexia are unable to comprehend spelled words or spell aloud.
Anterior alexia are able to understand some spelled words but cannot spell aloud

Front 9

What aphasic syndromes are associated with the three primary alexic syndromes?

Back 9

Central alexia = fluent aphasia
Anterior alexia = nonfluent aphasia
Posterior alexia = normal language output

Front 10

How are visual fields related to the three primary alexic syndromes?

Back 10

Anterior alexia is not associated with visual field deficits.
Posterior alexia associated with right hemianopia
Central alexia may present with right hemianopia

Front 11

Name the three linguistic subtypes of alexia.

Back 11

1. Phonological alexia
2. Surface alexia
3. Deep alexia
** all three are also dyslexic syndromes and are called examples of central dyslexia, meaning impairment is in language processing.

Front 12

What features are associated with phonological alexia/dyslexia?

Back 12

Hypothesized that lexical and nonlexical reading routes are impaired, but non-lexical is more impaired so person relies on faulty lexical-semantic reading route.
1. inability to follow spelling-to-sound correspondence rules
2. real words are mistaken for visually similar real words (called visual paralexias: "cat" read for "car"), but rarely make semantic errors
3. Errors are visual/derivational as indicated in #2
3. May be better able to read high frequency words and content words
4. Word reading is less impaired than with deep dyslexia
5. impaired spelling

Front 13

What features are associated with suface alexia/dyslexia?

Back 13

Hypothesized impaired lexical reading route such that person relies on relatively intact nonlexical route.
1. grapheme-to-phoneme conversion disorder
2. can't read irregular orthography words (e.g., "tough" read as "tug")
3. able to read regularly spelled words and non-words
4. errors are attempts to regularize irregular words (see #2)

Front 14

What features are associated with deep dyslexia?

Back 14

Hypothesized to be impaired lexical and non-lexical reading routes (particularly non-lexical route). Person relies on faulty semantic reading route.
1. Primary feature is reading errors based on semantic substitutions for target words (semantic paralexia)
2. Common visual errors with many semantic errors
3. high-image words read better than low-image
4. high-frequency ready better than low-frequency
5. content words read better than function words (function/syntact words are almost totally omitted)
6. read regularly and irregularly spelled words with the same accuracy
7. substituted words may be semantic paralexia, totally incorrect word, or neologism (e.g., "infant" could be read as "baby", "basement" or "garvon"
8. cannot read pseudo words

Front 15

Differentiate between hemi-alexia and hemi-spatial alexia

Back 15

Hemi-alexia can read in one visual field but not the other (seen when posterior CC is severed but both hemisphere are intact)
Hemi-spatial alexia: can read only half of word (seen with homonymous visual field deficit or unilateral attention deficit)

Front 16

Compare literal alexia to verbal alexia.

Back 16

Literal Alexia refers to the inability to recognize letters of the alphabet. Classic feature of Anterior Alexia.
Verbal alexia refers to the inability to recognize words with preserved ability to recognize letters. Feature of Posterior Alexia.

Front 17

Define paralexia.

Back 17

Substitutions made when reading aloud.
Includes literal, semantic, phonemic errors.

Front 18

Define attentional dyslexia and spatial dyslexia.

Back 18

Attentional dyslexia: gross disturbance in reading multiple words or text. Due to disturbance in visual attention. Single-word reading is relatively spared.
Spatial dyslexia: reading disorder based on difficulty perceiving location of letters or words, and/or difficulty maintaining correct sequence of lines of print. Generally due to right hemisphere injury.

Front 19

Define Central Dyslexias.

Back 19

Disorder is due to disruption of "higher language processing". Affects the processes by which word forms activate meaning or speech production. Constrasted with "peripheral dyslexia".
Includes deep dyslexia, phonologic dyslexia, suface dyslexia, alexia with agraphia.

Front 20

Peripheral Dyslexias.

Back 20

Disorder thought to be due to visual processing deficits in which visual inputs cannot be associated with stored representations of the written words.
Includes alexia without agraphia, attentional alexia, neglect alexia, spatial alexia.