Levels of breakdown in impaired word retrieval

1. Levels of breakdown in impaired word retrieval Associate Professor Lyndsey Nickels Macquarie Centre for Cognitive Science (MACCS) Macquarie University, Sydney.

2. 4 people with word production impairments

3. Cognitive Neuropsychology: An Assumption • Treatment will be maximally effective only when the direction of treatment is determined by precise knowledge of the individual’s processing strengths and weaknesses. • Analysis limited to surface symptoms will not enable one to construct effective treatments because such symptoms can arise in various ways.

4. Arthur(acquired aphasia) Spider -> “ant”

5. Arthur(acquired aphasia) Pocket -> “sleeve”

6. Marie(developmental language impairment) Pineapple -> “not apple juice, oh the fruit with the funky hairdo” From Best, 2005

7. Chris(acquired aphasia) Submarine -> /su:pbnn sbbri: sb mri:n/

8. Chris(acquired aphasia) Elephant -> /efl .. efltn lfnnt lfnnt lftn lfnt elfn eflnt /

9. Becca(Developmental language impairment) Hospital -> /hstəbəl/ From Best 2005

10. Different error types in word retrieval Arthur & Marie make semantic errors Arthur spider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors Chris Submarine -> /su:pbnn sbbri: sb mri:n/ Becca Hospital -> / hstəbəl/ WHY do these different error types occur?

11. Pic naming d-o-g c-a-t f-i-sh g d o Picture naming tail purrs fur Lexical semantics fins barks pet 4-legs Phonological output lexicon d-o-g c-a-t f-i-sh f a a i c sh c t t Phonological output buffer cat

12. How do semantic errors occur? Arthur Spider -> “ant” Marie Pineapple -> “the fruit with the funky hairdo” Semantic errors are most commonly attributed to semantic impairments ……. i.e. Impaired representation of word meanings

13. spoken naming –sem deficit –threshold to phoneme level d-o-g c-a-t f-i-sh g g d d o o Picture naming (with semantic impairment) tail purrs fur Lexical semantics fins barks pet 4-legs d-o-g d-o-g c-a-t Phonological output lexicon f-i-sh f a i sh c t Phonological output buffer dog

14. spoken naming –sem deficit –threshold to phoneme level g g d d o o Semantic errors (without semantic impairment) tail purrs fur Lexical semantics fins barks pet 4-legs d-o-g d-o-g c-a-t d-o-g c-a-t f-i-sh Phonological output lexicon f-i-sh f a i sh c t Phonological output buffer dog

15. Summary: Semantic errors Two possible levels of impairment in spoken word production • Semantic impairment • Post semantic impairment • Access to phonological representation (or loss of those representations) Semantic errors are a symptom which can have as their cause different underlying levels of impairment. How can we distinguish these different levels of impairment?

16. How do we determine the underlying level of impairment? - examine performance on other tasks that also use some of the processing components involved in word production. - if a person with language impairment can perform a task that utilises one of these components as accurately and as fast as a non-brain damaged person of the same age, education and culture, then it can be assumed that that component is not the source of the difficulty in word production.

17. Print Heard Speech Pictures, seen objects Lexical Semantics Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer Writing Speech output

18. Print Heard Speech Post-Semantic impairment Speech output: Pictures, seen objects Lexical Semantics Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer Writing Speech output

19. Print Heard Speech Post-semantic impairment Speech output: (semantic errors) Written output: Speech comprehension: Written comprehension: (assuming no additional impairments)  Pictures, seen objects ok Lexical Semantics ok Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer ok Writing Speech output

20. Print Heard Speech Semantic impairment Speech output: Written output: Speech comprehension: Written comprehension: Pictures, seen objects Lexical Semantics Lexical Semantics Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer Writing Speech output

21. Print Heard Speech Semantic impairment Speech output: (semantic errors) Written output: Speech comprehension: Written comprehension:   Lexical Semantics Lexical Semantics  Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer  Semantic errors in all modalities Writing Speech output

22. Summary

23. Print Assessment of semantic processing in comprehension Heard Speech Pictures, seen objects • Require an assessment that has semantically related distractors • Perform the assessment in both spoken and written forms Lexical Semantics Lexical Semantics Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer Writing Speech output

24. Word-picture matching with semantically related distractors Close semantic distractor Unrelated distractor Distant semantic distractor target Similar assessment of comprehension found in PALPA.

25. Word-picture verification (a more sensitive test of semantic impairments) Target (response: ‘yes’) Is this a pair of shoes? Semantically related distractor (response: ‘no’) Is this an aeroplane? Unrelated distractor (response: ‘no’ ) Is this a water melon?

26. Pyramids & Palm trees (Howard & Patterson, 1992) pyramid “pyramid” Arthur: 3 picture version: 87% 1 written word-2 pictures: 87% 1 spoken word-2 pictures: 85% Semantic impairment N=52 Controls score 94% correct or higher

27. Marie(developmental language impairment) Squirrel - nut test (Pitchford & Eames, 1994) • 95% correct (within normal limits for age matched controls) British Picture Vocabulary Scale • Standard Score 99 (average =100) Post-semantic impairment restricted to spoken word production

28. Different error types in word retrieval Arthur & Marie make semantic errors Arthur spider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors Chris Submarine -> /su:pbnn sbbri: sb mri:n/ Becca Hospital -> / hstəbəl/

29. Different error types in word retrieval Semantic impairment Arthur & Marie make semantic errors Arthur spider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors Chris Submarine -> /su:pbnn sbbri: sb mri:n/ Becca Hospital -> / hstəbəl/ Post-Semantic impairment

30. Unimpaired spoken naming – d-o-g c-a-t f-i-sh g d o Picture naming tail purrs fur Lexical semantics fins barks pet 4-legs Phonological output lexicon d-o-g c-a-t f-i-sh f a a i c sh c t t Phonological output buffer cat

31. Unimpaired spoken naming – d-o-g c-a-t f-i-sh g d o Picture naming (phonological errors) tail purrs fur Lexical semantics fins barks pet 4-legs Phonological output lexicon d-o-g c-a-t f-i-sh f a a i c sh  c t t Phonological output buffer ca_ cag

32. Print Heard Speech Pictures, seen objects Repetition of nonwords Lexical Semantics Sublexical reading Phonological Output Lexicon Orthographic Output Lexicon Phonological Output Buffer Graphemic Output Buffer Writing Speech output

33. Yes No No Length effect ok ok ok Yes

34. 1 syllable: 86% 3 syllable: 23% Naming Reading Repetition (words & nonwords)

35. Chris – examples of errors across tasks

36. How do we decide which treatment? Each different level of breakdown in word production will be best remediated by a different type of treatment (e.g. Hillis & Caramazza, 1994; Nettleton & Lesser, 1991) • impaired word meaning (semantics) → treatment focusing on meaning • impaired retrieval of the phonological form from semantics → treatment focusing on providing/accessing the phonological form • impaired phoneme level/phonological encoding • treatment focusing on phonemes

37. How do we decide which treatment? Each different level of breakdown in word production will be best remediated by a different type of treatment (e.g. Hillis & Caramazza, 1994; Nettleton & Lesser, 1991) Do we have evidence that this approach works? Yes and No!!

38. Do we have evidence that this approach works? Developmental Literature Several studies have contrasted semantic and phonological tasks (e.g. Wing 1990, Hyde Wright et al. 1993) … with conflicting results BUT they have not identified the level of breakdown in the children treated AND examined the children as a group

39. What treatment is appropriate? Acquired Aphasia literature: Word retrieval impairments Tasks focusing on semantics and phonology - improve word retrieval e.g. Howard et al 1985 Nickels & Best 1996 Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

40. What treatment is appropriate? Acquired Aphasia literature: Word retrieval impairments All the tasks involve activation of both semantics and phonology But may focus more on semantics…. Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

41. What treatment is appropriate? Acquired Aphasia literature: Word retrieval impairments All the tasks involve activation of both semantics and phonology But may focus more on semantics or phonology Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech Repeat “kangaroo” It starts with /k/

42. What treatment is appropriate? Acquired Aphasia literature: Word retrieval impairments All the tasks involve activation of both semantics and phonology They produce long lasting, item specific effects in the majority of individuals with impaired activation of the correct target in the phonological lexicon Improves likelihood of the target being sufficiently activated to be retrieved successfully. Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

43. What treatment is appropriate? Acquired Aphasia literature: Semantic impairments The most successful therapy seems to involve exploring the semantic attributes of a stimulus. e.g. Boyle & Coelho, 1995. Coelho, McHugh & Boyle, 2000. Hillis, 1991, 1998. Nickels & Best, 1996. Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

44. What treatment is appropriate? e.g. Nickels & Best (1996) AER (Arthur) “Relatedness judgements” (with feedback) Acquired Aphasia literature: Semantic impairments Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech Improved naming of treated and untreated stimuli

45. What treatment is appropriate? Acquired Aphasia literature: Treatment of phonological errors Relatively little adequate published work Franklin, Buerk, and Howard (2002) MB • long sequences of phonologically related responses in all speech-production tasks • Good monitoring ability • therapy included phoneme discrimination tasks • judgments of accuracy of target attempts Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

46. What treatment is appropriate? Acquired Aphasia literature: Treatment of phonological errors Relatively little adequate published work Franklin, Buerk, and Howard (2002) MB • generalised improvement across items and modalities • they propose that treatment improved the phoneme selection impairment Lexical Semantics Phonological Output Lexicon Phonological Output Buffer Speech

47. Summary • Identified (some of the) the different levels of breakdown that can underlie spoken word production impairments • Semantic • Post semantic • Phoneme activation • Demonstrated that there is evidence that treatment targeted at these levels of breakdown can be successful (at least in the acquired aphasia literature)

48. Conclusions The Cognitive Neuropsychological approach requires.. • Systematic assessment of the component processes of language processing • In order to establish which of these processes are intact and which impaired • Therapy will have the best chance of being successful only when the cause of the language symptom is understood • These techniques can be applied to both developmental and acquired language disorders.

49. Thank you for your attention. Any questions or for further details, please do not hesitate to contact me: lnickels@maccs.mq.edu.au