Week 6 - Visual Word Recognition Flashcards
Visual Orthographic Analysis
what is it and what does it do?
Each letter = one unit – A=a • Font or case irrelevant • Identifies letters • Codes letter position • May perceptually groups letter together – CHURCH = CH/UR/CH • Used for words and nonwords
Orthographic input lexicon
What is it? What does it do?
Visual word recognition units • Store of familiar written words • Lexicon of printed words • Used to differentiate between familiar and unfamiliar words • Word activation occurs over time
Grapheme-Phoneme Conversion
What is it? What does it do?
• Letter to sound rules • GPC rules • Read words and nonwords by translating graphemes into phonemes – letters sounds • Cannot use successfully for irregular words e.g. have, done
Semantic system (What is it? What does it do?)
• Semantic memory
• Meaning of spoken word, written word and
objects known to person
• Not sure how concepts are represented in
this system
• One idea each unit semantic system =
feature
• Comprehension of a word or object involves
activation each unit that corresponds to the
of feature(s) of a word/object
• Activation occurs over time
Orthographic output lexicon
What is it? What does it do?
Mental dictionary of all the words you can spell or write • Lexicon for spelling/writing of words • Lexical activation rises over time • Intended spelling goes to Orthographic Output Buffer
Orthographic output buffer
What is it? What does it do?
• Holding buffer for temporary storage of material from Orthographic Output Lexicon • Holds sequences of letters until word production is complete • Needed as writing or spelling of a word may require repeated search Orthographic Output Lexicon for each letter slow process • Word length effects operate here
Phonological output lexicon
What is it? What does it do?
• Lexical entries of person’s own vocabulary • Store of spoken form of familiar words • Activation rises over time • Activations starts from time person intends to say word • Higher frequency words ‘recognised” earlier than lower frequency words
Phonological output buffer
What is it? What does it do?
• Temporary storage for phonemes to be uttered • Easier than a phoneme by phoneme production of speech • Slips of the tongue occur here • Word length effects operate here
Phoneme-to-grapheme conversion
• Sound to letter rules • Grapheme: Letter or sequence of letters • Phoneme: sounds of letter(s) • Use PGC rules translate spoken word or nonword to spelling – Yacht – yot – Phone – foan or fone • Spelling of unfamiliar words or nonwords
What are the tests for Visual Orthographic Analysis?
Test: Cross case matching • Mark the capital letter that matches the small letter – f – T F
Test: Word or Nonword matching • Do these two words (nonwords) have the same letters in them? – Tower-TOWER – lmeon- DMEON
What are the tests for Orthographic Input Lexicon?
Test: Written lexical decision
• Is this a real word?
– KED
– DOLL
Test: Read aloud exception words
• Please read these words to me
– YACHT
– PINT
Test: Understand written words (define,
match to picture)
• Point to the picture of a GOAT
What are the tests for Grapheme-Phoneme Conversion?
Test: Read aloud nonwords
• Please read aloud these nonsense words
– KED
– NAR
Test: Decide if a printed nonword sounds like a real word • Point to the made up word below that sounds like the word FOX – Phocks Phoalks
What are the tests for the Semantic System?
Test : Match pictures and written
words
• Which picture matches the word
SPIDER?
Test : Name to written definition
• Write down the name of the animal
known as the king of the jungle
– LION
• Tell me the name of the animal known
as the king of the jungle
– “LION”
Test : Define to written name • Please write down the meaning of the word CHAIR. • Tell me what is meant by the word CHAIR? – Something you sit in or on
Test : Written synonym judgement • Read the two words below and tell me if they have the same meaning. – Big Large – Round Corner
Test : Associates of written words
• Point to the picture that goes with the
word
– MOP
What are the tests for the Orthographic Output Lexicon?
Test: Written naming to written definition • Write down the name of the animal known as the king of the jungle – LION
What are the tests for the Orthographic Output Buffer?
Test: Written naming to written definition (unaffected by letter length) • Write down the name of the animal known as the king of the jungle – LION • Write down the name of the animal that is grey in colour and has large ears and a trunk. – ELEPHANT
Test: Spontaneous text writing
(unaffected by letter length)
• Write down what you did yesterday
– I went for a walk along the seaside and
saw some birds flying around.
– I went for a walk along the sea…side and
saw some birds fly…ing…ar..ound.
What are the tests for the Phonological Output Lexicon?
Test: Spoken naming to written definition • Tell me the name of the animal known as the king of the jungle – LION
Test: Spontaneous speech
• Tell me what you did yesterday
− I went for a walk along the sea & saw some birds.
− I we…went..f..for…a…a…sea..
What are the tests for the Phonological Output Buffer?
Test : Spontaneous speech (unaffected
by syllable length)
• Tell me what you did yesterday
– I went for a walk along the seaside and
saw some birds flying around.
– I went for a walk along the sea…side and
saw some birds fly…ing…ar..ound
Test: Spoken naming to written definition (unaffected by syllable length) • Name the animal known as the king of the jungle – LION • Name the animal that is grey in colour and has large ears and a trunk. – ELEPHANT
What are the tests for Phoneme-Grapheme Conversion?
Test: Write exception words as they sound • Please write each word out as they it sound – YACHT = YOT – FOX= focks – PHONE = fone
Types of Dyslexia
• Acquired dyslexia • Developmental dyslexia • Peripheral dyslexias: affect early stages in word recognition such as visual analysis of letters or words • Central dyslexias : affect deeper processes e.g. GPC, semantic access
Types of Peripheral Dyslexia
- Neglect dyslexia
- Letter-by-letter reading
- Attentional dyslexia
- Visual dyslexia
Neglect dyslexia
• Right hemisphere damage (parietal lobe) –
unilateral neglect
• Patient does not attend to left side of space
• Neglect dyslexia patient does not read left/right
half page or word (Haywood & Coltheart, 2000)
• Not a consequence of unilateral neglect
• Occurs
– due to difficulty in specification of the word
at the level of visual orthographic analysis
Neglect dyslexia Errors:
Errors are
• Spatially determined visual errors consistently in
left/right side of a word a neglect point in
visual word reading
• All letters correct on preserved side
• Letters incorrect on the neglected side
• Errors – similar to original word in length
Neglect dyslexia errors (left vs right side)
- Left side neglect
- liquid -> squid
- cage -> rage
- yellow => pillow
- Right side neglect
- book => boot
- milk => mill
- pen => pet
What is Letter-by letter reading (Pure Alexia
or Spelling Dyslexia)?
• Can identify letters • Reads words one letter at a time • Do not have direct visual access to the normal reading system • Writing and spelling unaffected • Patient will name (or misname) some or all of the letters before a response is made • Response times increase as word length increases
What else about Letter-by letter reading (Pure Alexia
or Spelling Dyslexia)?
• Occasionally can name short words without
spelling
• Lesion typically located inferior portions of
occipital lobe bordering on temporal lobe in
left hemisphere
• Problem with early visual processing or
breakdown of letter and word connections
• Impaired visual orthographic analysis or
accessing the orthographic input lexicon
Attentional dyslexia
• Person can recognise a single letter or a
single word in isolation but cannot recognise
the same word or letter if it is shown with
items of the same type
• Exact location of lesion unknown but
patients typically have damage to posterior
left-hemisphere including subcortical
structures
• Difficulty with the visual specification of the
word at the visual orthographic analysis
level
What else about Attentional dyslexia?
Attentional dyslexia (cont)
• could read single words
• poor at naming letters within the words they could
read
– BFXQL – identify centre letter, patent would produce F
or Q not X
• Presented with two words would move location of
letters
– Win Fed fin fed
• Problem with narrowing attention
• Deficit letter to word binding
Visual Dyslexia
• Patients misidentify a word for one that is
visually similar
– e.g. lend land or calm claim
• brief presentation normals make same errors
• difficulty at either the visual orthographic level
of analysis or in gaining access to the
orthographic input lexicon
Types of Central Dyslexia
- Surface dyslexia
- Phonological dyslexia
- Deep dyslexia (covered next week)
Surface Dyslexia
• Regular words read better than irregular words
– MINT FEAR VS PINT BEAR
• Preserved nonword reading
• Many patients worse at reading nonwords than
matched real words
• Impairment of lexical route to reading aloud with
intact GPC rules (orthographic input lexicon)
• Errors
– Regularizations (yacht, sew)
– Visual errors (subtle sublet)
– Misapply letter to sound rules (rule of E rage rag)
Phonological Dyslexia
• Poor or flawed nonword reading • Problems reading new words • Nonwords read as visually similar words – SOOF soot – KLACK slack • OK for well known words • Impaired sub-lexical (non-lexical) route to reading aloud (impaired GPC module)
Phonological Dyslexia Errors
– Visual
– Visual =>semantic
– Morphological errors
