alexia Flashcards
reading is based on _______ system alone
visual
writing requires input from _________ system as well as _____ system
motor-kinesthetic and visual
brain areas involved in writing from dictation (listening and writing down)
-superior temporal gyri
-speech perception pathway along left superior temporal gyrus
-posterior temporal and frontal premotor regions (auditory motor integration)
writing involves inputs from
temporal, parietal, frontal, and to some extent occipital regions
alexia
reading deficits following a brain damage
-acquired in nature
-different than dyslexia
pure alexia
no other disorder present; people with mild deficits are better at identifying letters than words
alexia with agraphia
impaired reading and writing deficits following the onset of aphasia
alexia without agraphia (pure word blindness)
impaired reading with relatively intact writing skills
cause of alexia without agraphia
combination of 2 lesions: left occipital cortex and splenium of corpus callosum
disconnect between right visual cortex and left language cortex (alexia without agraphia)
can include deficits in reading information located on the person right visual field
optic aphasia
seen with pure alexia where person is unable to name visual stimuli although they name same stimuli through other modalities
-left occipital and corpus callosum lesions
dominant hemisphere related lesions
typically results in alexia with agraphia
non-dominant hemisphere damage
alexia without agraphia (neglect and attentional alexia)
alexia associated with aphasia
factors affecting both auditory comprehension and reading skills
-word frequency
-personal relevance
-part of speech
-synctactic complexity
-emotionality
central alexia
occurs in dominant hemisphere. often seen as a consequence of aphasia
-deficits in language comprehension, expression, and reading
(phonological, deep, surface)
phonological alexia
common; difficulties with grapheme-phoneme rules, able to read words they recognize but have difficulties with unfamiliar words; moderate severity (inbetween deep and surface)
deep alexia
most severe; deficits in decoding grapheme-phoneme rules with INTACT ability to derive meanin from whole words
key features of deep alexia
-semantic paralexia - frequent substitution of semantically related words (saying she for her)
-poor ability to apply grapheme-to-phoneme rules evident with non-words
pure alexia
exclusive deficits in reading
surface alexia
least severe; have trouble recognizing the meaning of printed words. can sometimes read less familiar or unknown words because of relatively good grapheme-to-phoneme knowledge
peripheral alexia
alexia due to interruptions or damage to visual cortex. occurs in non-dominant hemisphere
(heianopic, neglect, attentional)
hemianopic alexia
caused due to damage to primary visual cortex and leading to loss of up to 50% of the visual field
neglect alexia
difficulties in identifying the beginning of a word; can be associated with RHD or isolated symptom
attentional alexia
reader may see crowded letters sometimes leading to blending of two words into one. difficulty distingushing between 2 words.