Alexia with hemianopsia & achromotopsia suggests a lesion in the
Dominant occipital-temporal area
Neuroanatomical correlate of phonological agraphia
Supramarginal gyrus or insula (assoc. w/ alexia) Perisylvian region (assoc. w/ aphasia)
Area just superior to Broca's believed to be associated with agraphia
What are the two general nosologies of agraphia?
Clinical neurology classification (aphasic & nonaphasic agraphias) Cognitive neuropsychological classification (phonological & lexical agraphia)
Reading, writing, or speaking error at the single word level in which the correct morpheme root is retained but differs in part of speech (e.g., 'confuse' for 'confusion')
Neuroanatomical correlate of alexia with agraphia
Dominant angular gyrus in the inferior parietal lobe
Writing impairment due to spatial deficits that affect nonlinguistic aspects of writing
Characterized by relative preservation of single-word reading in context of gross disruption of reading when words are presented as text or in the presence of other words or letters
Alexia without agraphia is associated with what other conditions?
R HH, color naming disturbance
Visual-spatial agraphia (constructional agraphia) is characterized by
Reiteration of strokes Inability to complete a straight horizontal line Insertion of spaces between graphemes
Surface alexia is associated with lesions in the
L temporal lobe
Hans Berger's primary acalculia
Disturbance in performing calculations specifically
Writing impairment associated with poor written production characterized by frequent omission errors w/ well-formed letter production (may reflect wrong letter); copying & oral spelling are spared
Neuroanatomical correlate of surface/lexical agraphia
Posterior angular gyrus & parieto-occipital lobule (assoc. w/ aphasia)
What other conditions are often associated with acalculia assoc. w/ alexia & agraphia for numbers?
Aphasia, verbal alexia, ideational & ideomotor apraxia, constructional deficits, somatognosia
Literal alexia is associated with a lesion in the
left frontal area
Reflects impairment of sound-to-letter correspondences (nonlexical spelling route); markedly impaired spelling of nonwords & unfamiliar words but can spell words with which they are familiar
Peripheral vs. central dyslexias (Shallice & Warrington)
Peripheral - characterized by deficit in processing of visual aspects of stimulus, which prevents pt from reliably matching familiar word to stored form (e.g. alexia without agraphia) Central - impairment to deeper or higher reading functions by which visual word forms mediate access to meaning or speech production mechanisms
Impaired ability to spell & write with meaning; may produce semantic jargon, spell semantically incorrect but correctly spelled dictated homophones; common finding in AD & semantic dementia
Hecaen's classifications (1961) of acalculia
1) Acalculia assoc. w/ alexia & agraphia for numbers 2) Acalculia of the spatial type 3) Anarithmetria
Neuroanatomical correlate of anarithmetria
Left-sided & bilateral brain disease; RH only if parietal lobe is involved
What other conditions are often associated with anarithmetria?
Aphasia, visuoconstructive deficits, general cognitive deterioration, verbal alexia, visual field defects
Alexia without agraphia is also known as
Individual can read adequately in one visual field but not other; often seen when posterior CC is severed but both visual sensory areas remain intact
Alexia for arithmetical signs with preserved reading of #s is associated with what type of lesion?
Focal LH lesion in parietal or temporal-occipital areas
The origin of our current concept of alexia stems from case reports by _______
Inability to read or write #s is associated with a lesion in the
L parietal lobe
Not apraxia agraphia because can hold pen, but difficulties with all the motor steps needed to write
Brain abnormalities associated with reading disorders
Symmetrical planum temporale, cortical malformations in frontal & temporal areas, reduced insular & frontal lobe volumes
Neuroanatomical correlate of alexia without agraphia
Dominant occipital lobe, involves white matter of posterior corpus callosum
Alexia with agraphia is also known as
Who coined the term 'akalkulia' in 1919?
Phonological agraphia is often associated with what other disorders?
Aphasia, phonological alexia
What is the difference between alexia & dyslexia?
Alexia - acquired Dyslexia - congenital/early life
Agraphia in isolation is assocaited with a lesion in
Dominant superior or inferior parietal lobe or second frontal gyrus
Abnormal repetition of phrases, words, letters, etc. often seen with frontal lobe dementia
Hans Berger's secondary acalculia
Problems with calculations due to more general disturbances in memory, language, attention, etc.
Who was the first to publish a detailed report of a calculation disorder resulting from focal brain damage?
Stadelman (1908); the patient also had R HH
Alexia with agraphia is often accompanied by
Fluent aphasia, Gerstmann's syndrome, hemisensory loss, R visual field defect
Neuroanatomical correlate of acalculia of the spatial type
Post-Rolandic lesion of the RH
Neuroanatomical correlate of deep agraphia
Supramarginal gyrus or insula, far extending
Acalculia of the spatial type
Impaired spatial organization results in calculation problems due to misalignment of numbers, reversal of digits, inversions, & reversal errors
McCloskey & Caramazza's subclassification of number processing skills
Lexical processing - ability to read or write individual numbers Syntactic processing - ability to combine numbers into correct form & quantity
The origin of the concept of alexia is from case reports by
Substitutions made when reading aloud
Phonological alexia (dyslexia)
An inability to make spelling-to-sound correspondence rules; results in visual paralexias - real words misread as visually similar words ('cat' for 'car'); better reading of high frequency words
AKA frontal or anterior alexia; can read whole words but not recognize individual letters; associated with severe agraphia, poor copy with omissions, agrammatism, poor spelling
Dual-route model for spelling
Lexical: processes words holistically; cannot process unfamiliar or non-words Non-lexical: processes words on subword level, fragmenting them into phonological components; cannot correctly process irregular words
Trouble spelling nonwords, more trouble spelling function words than nouns, semantic paragraphic errors ("flight" instead of "propeller")
Alexia without agraphia (posterior alexia) is considered a disconnection syndrome because it disconnects ______ from _______
Visual info; language cortex
Deficits in performing the calculation itself
Metaphorical term for the inability to put thoughts into written phrases
Surface alexia (dyslexia)
Grapheme-to-phoneme conversion disorder; can't read words with irregular orthography (e.g., 'tough' read as 'tug')
According to Neilson's model, what are the 3 forms of agraphia?
Aphasic, apretic (basically apraxic), isolated
Deep alexia (dyslexia)
Reading errors based on semantic (real word) substitutions for target words (semantic paralexias); substituted word may be paralexia, totally incorrect, or neologism; syntactic (functional) words are almost totally omitted
Inability to copy written or printed words while being capable of writing from dictation; associated with lesions in the posterior language-dominant hemisphere
Lexical agraphia is often associated with what other disorders?
Aphasia, alexia, Gerstmann syndrome
Selective impairment of lexical (whole-word) spelling route that results in overreliance on spelling by sound-to-letter correspondence; inability to spell irregular words ('feign' becomes 'fane')
Alexia with agraphia is associated with a lesion in the
Inferior parietal lobe of LH, centering on angular gyrus
Primary acalculia is associated with lesions in
Dominant angular gyrus/inferior parietal lobe, dominant or nondominant perisylvian lesion
Agraphia, finger agnosia, L/R disorientation, alcalculia
Term used to indicate total loss of the ability to understand written or printed language; synonymous with central alexia but indicates total loss
Literal alexia is associated with what other conditions?
R HP, nonfluent aphasia, unilateral sensory/visual field neglect