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

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Presentation on theme: "Levels of breakdown in impaired word retrieval Associate Professor Lyndsey Nickels Macquarie Centre for Cognitive Science (MACCS) Macquarie University,"— Presentation transcript:

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 NAMEAGEDISORDER% CORRECT PICTURE NAMING ARTHUR65 yrsAcquired aphasia 54% MARIE8 yrsDevelopmental Language Impairment 65% CHRIS47 yrsAcquired aphasia 25% BECCA9 yrsDevelopmental Language Impairment 34%

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 Pocket -> “sleeve” Arthur (acquired aphasia)

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

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

8 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 -> /  ə  ə / From Best 2005

10 Different error types in word retrieval Arthur & Marie make semantic errors Arthurspider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors ChrisSubmarine -> /su:p  b  n  n s  b  bri: s  b m  ri:n/ BeccaHospital -> /  ə  ə / WHY do these different error types occur?

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

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

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

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

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

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

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

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

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

22 Summary Semantic impairment Post-semantic impairment Speech output  semantic errors Written output  semantic errors ok Speech comprehension  semantic errors ok Written comprehension  semantic errors ok

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

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

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

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% N=52 Controls score 94% correct or higher Semantic impairment

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 Arthurspider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors ChrisSubmarine -> /su:p  b  n  n s  b  bri: s  b m  ri:n/ BeccaHospital -> /  ə  ə /

29 Different error types in word retrieval Arthur & Marie make semantic errors Arthurspider -> “ant” Marie Pineapple -> “not apple juice, oh the fruit with the funky hairdo” Chris & Becca make phonological errors ChrisSubmarine -> /su:p  b  n  n s  b  bri: s  b m  ri:n/ BeccaHospital -> /  ə  ə / Semantic impairment Post-Semantic impairment

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

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

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

33 Semantic impairment Post-semantic /lexical access Phonological output buffer Speech output Errors  Semantic  Semantic  Phonological Written output  semantic ok Speech comp.  semantic ok Written comp.  semantic ok Phonological errors in repetition & reading No ok Yes No Length effect

34 Chris Phonological output buffer Speech output Errors Length effect  Phonological Yes Written output ok Speech comp. ok Written comp. ok Phonological Errors in repetition & reading Yes 1 syllable: 86% 3 syllable: 23% Naming Reading Repetition (words & nonwords)

35 Chris – examples of errors across tasks SubmarinePyramid Naming su:p  b  n  np  r  m  nt Reading s  b  r  li:npr  m  d  d Repetition sbmnsbmnpr  m  m  m

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 Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics

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…. Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics

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 Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics 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. Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics

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, Coelho, McHugh & Boyle, Hillis, 1991, Nickels & Best, Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics

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

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 Phonological Output Buffer Speech Phonological Output Lexicon Lexical Semantics

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:


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