Levels of breakdown in impaired word retrieval

Associate Professor Lyndsey Nickels

Macquarie Centre for Cognitive Science (MACCS)

Macquarie University, Sydney.

4 people with word production impairments

NAME AGE DISORDER % CORRECT PICTURE NAMING

ARTHUR 65 yrs Acquired aphasia

54%

MARIE 8 yrs Developmental Language Impairment

65%

CHRIS 47 yrs Acquired aphasia

25%

BECCA 9 yrs Developmental Language Impairment

34%

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.

Arthur(acquired aphasia)

Spider -> “ant”

Pocket -> “sleeve”

Arthur (acquired aphasia)

Marie(developmental language impairment)

Pineapple -> “not apple juice,

oh the fruit with

the funky hairdo”

From Best, 2005

Submarine -> /su:pbnn sbbri: sb mri:n/

Chris (acquired aphasia)

Chris (acquired aphasia)

Elephant -> /efl .. efltn lfnnt lfnnt lftn lfnt

elfn eflnt /

Becca(Developmental language impairment)

Hospital -> /əə/From Best 2005

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:pbnn sbbri:

sb mri:n/

Becca Hospital -> / əə /

WHY do these different error types occur?

f-i-sh

d og

purrs

barksfur

pet 4-legs

tail

fins

d-o-g c-a-t

cat

Phonological output lexicon

Phonological output buffer

Lexical semantics

Picture naming

ca

tf i s

hca

t

c-a-td-o-g f-i-sh

How do semantic errors occur?

Semantic errors are most commonly attributed to semantic impairments …….

i.e. Impaired representation of word meanings

ArthurSpider -> “ant”

Marie Pineapple -> “the fruit with the funky hairdo”

f-i-sh

d og

purrs

barksfur

pet 4-legs

tail

fins

d-o-g c-a-t

dog

Phonological output lexicon

Phonological output buffer

Lexical semantics

Picture naming

(with semantic impairment)

ca

tf i s

hd o

g

f-i-shc-a-td-o-gd-o-g

f-i-sh

d og

barksfur

pet 4-legs

tail

fins

d-o-g c-a-t

dog

Phonological output lexicon

Phonological output buffer

Lexical semantics

Semantic errors

(without semantic impairment)

ca

tf i s

hd o

g

f-i-shc-a-td-o-gd-o-g

purrs

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?

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.

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Post-Semantic impairment

Speech output:

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Post-semantic impairment

Speech output:(semantic errors)

Written output:

Speech comprehension:

Written comprehension:

(assuming no additional impairments)

ok

ok

ok

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Semantic impairment

Speech output:

Written output:

Speech comprehension:

Written comprehension:

Lexical Semantics

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Semantic impairment

Speech output:(semantic errors)

Written output:

Speech comprehension:

Written comprehension:

Lexical Semantics

Semantic errors in all modalities

Summary

Semantic impairment

Post-semantic impairment

Speech output semantic errors semantic errors

Written output semantic errors ok

Speech comprehension semantic errors ok

Written comprehension semantic errors ok

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

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Lexical Semantics

Word-picture matching with semantically related distractors

Distant semantic distractor

target

Close semantic distractor

Unrelated distractor

Similar assessment of comprehension found inPALPA.

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?

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=52Controls score 94% correct or higher Sem

antic

impa

irmen

t

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

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:pbnn sbbri:

sb mri:n/

Becca Hospital -> / əə /

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:pbnn sbbri:

sb mri:n/

Becca Hospital -> / əə /

Semantic impairment

Post-Semantic impairment

f-i-sh

d og

purrs

barksfur

pet 4-legs

tail

fins

d-o-g c-a-t

cat

Phonological output lexicon

Phonological output buffer

Lexical semantics

Picture naming

ca

tf i s

hca

t

c-a-td-o-g f-i-sh

f-i-sh

d og

purrs

barksfur

pet 4-legs

tail

fins

d-o-g c-a-t

ca_

Phonological output lexicon

Phonological output buffer

Lexical semantics

Picture naming (phonological errors)

ca

tf i s

hca

t

c-a-td-o-g f-i-sh

cag

Phonological Output Lexicon

Speech output

Phonological Output Buffer

Lexical Semantics

OrthographicOutput Lexicon

Graphemic Output Buffer

Writing

Heard SpeechPrint

Pictures, seen objects

Repetition of nonwords

Sublexical reading

Semantic impairment

Post-semantic /lexical access

Phonological output buffer

Speech outputErrors

Semantic

Semantic

Phonological

Written output semantic ok

Speech comp. semantic ok

Written comp. semantic ok

Phonologicalerrors in repetition & reading

No No

ok

ok

ok

Yes

YesNoNoLength effect

Chris Phonological output buffer

Speech outputErrors

Length effect

Phonological

YesWritten output ok

Speech comp. ok

Written comp. ok

PhonologicalErrors in repetition & reading

Yes

1 syllable: 86%3 syllable: 23%

NamingReading Repetition(words & nonwords)

Chris – examples of errors across tasks

Submarine Pyramid

Naming su:pbnn prmnt

Reading sbrli:n prmdd

Repetition sbmn prmmm

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

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!!

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

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

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

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/

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

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.

Phonological Output Buffer

Speech

Phonological Output Lexicon

Lexical Semantics

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

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

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

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)

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.

Thank you for your attention.

Any questions or for further details,

please do not hesitate to contact me:

lnickels@maccs.mq.edu.au