Language and Cognition Colombo, June 2011

1. Language and CognitionColombo, June 2011 Day 4 Psycholinguistic Assessments of Language Processing in Aphasia Acquired reading disorders With acknowledgement to Jane Marshall

2. Aims of Lecture • to further familiarise students with a cognitive model of reading • to familiarise students with methods of reading assessment • to familiarise students with patterns of acquired reading impairment

3. Mouse mouse print Abstract Letter Identification m s o e u “yes, these are letters” Visual Input Lexicon “yes, this is a word” Mouse = N Semantic System “yes, this word means something” Phonological Output Lexicon “this word is pronounced /maUs/” “mouse” speech

4. Blik blik print Abstract Letter Identification Visual Input Lexicon Grapheme to Phoneme Conversion b=/b/ , l=/l/, i=/I/, k=/k/ Semantic System • The lexical route cannot read nonwords at all • The nonlexical route cannot read irregular spelling-sound correspondences • We need (at least) both of these routes to be able to read both real and pseudo words Phonological Output Lexicon “blik” speech

5. Different Reading Routes If reading via GPC were the only option: Irregular words could not be read correctly: mortgage yacht Attempts to read these would result in regularisations Words would be understood by reading them aloud so homophones could not be distinguished: weak week gait gate air heir pain pane Some words can only be read correctly via meaning e.g. “bow” Take a bow, bow and arrow.

6. Pro Woman with dementia Profoundly confused, i.e. severe semantic deficit Poor comprehension of spoken and written words But Could read words aloud correctly Including irregular ones HYENA ‘hyena … hyena what the heck is that?’ (Schwartz, Saffran and Marin 1980) Reading Aloud Without Semantics?

7. Reading Routes Written word Visual Analysis Visual Input Lexicon Grapheme to Phoneme Conversion Semantics Phonological Output Lexicon Phonological Response Buffer speech

8. Frequency (eg Kucera and Francis) How often a word appears in a corpus of written texts or speech Familiarity Derived by asking people to rate the familiarity of words or objects Normal reading effects: frequency/familiarity

9. Frequency Effects High frequency words are processed faster than low frequency words in: • Reading aloud • Lexical decision (Balota and Chumbley 1984,1985) More slips of the tongue are made with low frequency words (Dell 1990)

10. Why do frequency effects occur? Different resting levels of activation for entries in the lexicons: dog elk Dog has a high resting level of activation; little further input is needed to make it ‘fire’. Elk has a low resting level of activation; more input is needed to make it ‘fire’.

11. Semantic Context Effects Word recognition facilitated by meaningful context She cleaned the dirt from her …. shoes hands terms ‘Shoes’ needs least exposure time to be recognised (Harley 2008)

12. Semantic Priming Lexical Decision Preceding word Word to be judged dog cat (fast) dog cap (slow) Recognition is speeded up by the previous presentation of a related word

13. Explanations for Context and Priming Effects ‘Top down’ assistance from semantics • Related words are linked in the semantic system via shared features. Seeing ‘dog’, therefore, partially activates ‘cat’. Feedback to VIL primes recognition of ‘cat’ An effect of association • ‘dog’ and ‘cat’ are strong associates, so are linked in the lexicons.

14. Imageability Effects High imageability words • Can generate a mental picture • Are concrete • Examples: elephant, book Low imageability words • Cannot generate a mental picture • Are abstract • Examples: democracy, idea

15. Imageability Effects • High imageability words are recognised and comprehended faster than low imageability words. • There seems to be an intrinsic advantage for concrete over abstract words • Confound with Age of Acquisition? Concrete words are learnt earlier than abstract words.

16. Predicting Problems: Visual Analysis Written word Visual Analysis VIL Grapheme to Phoneme Conversion Semantics POL Buffer speech

17. Predicting Reading Patterns If Visual Analysis is impaired: • All reading tasks are difficult, since VA is required in all reading routes • Basic visual tasks are impaired e.g. Cross case matching • Visual errors e.g. Lend read as land.

18. Tests for Visual Analysis Cross Case Matching R r B d Letter Discrimination TOWER tower EERGN eergd Tower TOWEL eergn EERGN

19. Predicting Problems: VIL Written word Visual Analysis VIL Grapheme to Phoneme Conversion Semantics POL Buffer speech

20. VIL Impairment: Predicted Patterns Reliance on GPC route. Therefore: • Reading aloud: Regular words better than irregular words • Regularisation errors in applicable languages (not Spanish and ?Sinhala/Tamil) • yacht read as ‘yakt’ • Mortgage read as ‘mort – gage’ • Non words can still be read aloud • Lexical decision poor Surface Dyslexia = dependency on GPC to read aloud

21. VIL Impairment: Predicted Patterns Comprehension Words understood by reading them aloud (via GPC) Target word read aloud definition Bear beer a drink Listen Liston the boxer Homophones cannot be disambiguated Target Read aloud Definition Pane pane something that hurts Berry berry dig in the ground

22. Predicting Patterns: GPC Impairment Written word Visual Analysis VIL Grapheme to Phoneme Conversion Semantics POL Buffer speech

23. Predicting Patterns: GPC Impairment Reading Aloud • Non words impaired (typically lexicalised) • Words unimpaired Lexical Decision: • Intact Reading Comprehension • Intact Termed: Phonological Dyslexia – dependency on lexical routes

24. Predicting Patterns: Semantic Impairment Spoken word Written word Auditory Analysis Visual Analysis AIL VIL Semantics GPC POL Buffer speech

25. Predicting Patterns: Semantic Impairment Problems in all tasks requiring access to word meaning • Reading Comprehension • Spoken word comprehension • Word production Semantic errors, eg dog matched to cat

26. Why Do Semantic Errors Occur? animal Likes walks mammal barks Can be trained Semantic features of DOG

27. Why Do Semantic Errors Occur? animal Likes walks mammal barks Can be trained If some semantic features are lost/inaccessible, ‘dog’ cannot be distinguished from ‘cat’. But can be distinguished from an unrelated item

28. Predicting Patterns: Semantic Impairment Reading performance depends upon what else is available What if .. GPC and Direct routes are also damaged?

29. Impairment in Semantics, GPC and Direct Route Spoken word Written word Auditory Analysis Visual Analysis AIL VIL Semantics GPC POL Buffer speech

30. Impairment in Semantics, GPC and Direct Route Reading performance Unable to read non words Semantic errors when reading, eg dog read as ‘cat’ Reading affected by semantic factors, eg • concrete>abstract • Nouns>verbs • Content>function words Termed: Deep Dyslexia (usually also visual errors)

31. Predicting Patterns: Deficit in POL Spoken word Written word Visual Analysis Auditory Analysis AIL VIL Grapheme to Phoneme Conversion Semantics POL Buffer speech

32. EST (Kay and Patterson, 1985) • Reading Aloud: • Non words 67/80 • Regular words>Irregular words • Regularisation Errors • Good lexical decision

33. EST (Kay and Patterson, 1985) Comprehension Could define irregular words (which he could not read aloud), eg: Thyme it grows and smells nicely Choir singing Could match irregular words to a definition, eg: Gauge the distance between rails of a railway track a deep valley with steep sides (gorge) dig something out with your hands (gouge)

34. EST: The Story EST can - access VIL (hence good lexical decision) - access Semantics (hence good performance on definition tasks) Reading aloud is impaired by deficit at POL GPC is available, hence relatively good reading of non words With regular words, GPC can be used to assemble a pronunciation; this does not work with irregular words.

35. Letter by Letter Reading The person reads by first naming the letters: Horse ‘aitch ..oh ..are .. ess .. ee .. horse’ Length effect: short words > long words Good writing Sometimes termed ‘pure alexia’ or ‘alexia without dysgraphia’

36. Letter by Letter Reading: Processing Account • Some Visual Analysis is occurring – hence letter naming • Access to VIL seems blocked – hence whole words cannot be recognised • GPC reading not available – hence regular words no better than irregular • Reading via intact spelling skills? But: • There may be covert skills in letter by letter reading, eg lexical decision may be possible with rapidly presented words

37. Summary • Different loci of impairment give rise to different reading patters • These reflect what is / is not available in the system • Carefully structured assessment helps to uncover processing strengths and weaknesses • Assessment findings inform therapy decisions