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When should we be concerned about late-talking toddlers?

Dorothy V. M. Bishop

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Wide variation in age at first words

Language milestones

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Girls sentences

Boys, single words

Girls, single words

Neligan, G. A., & Prudham, D. (1969). Norms for four standard developmental milestones by sex, social class and place in family. Developmental Medicine and Child Neurology, 11, 413-422.

Epidemiological sample of children born in Newcastle-upon-Tyne

Single words-”Three or four different words for people or objects, correctly used.”Sentences-”Three or more words, strung together to make some sort of sense.”

% childrenwith wordsor sentencesat given age

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Most children with long-term language problems were late talkers

Language milestones

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0 12 24 36 48 60

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SLI

Red shows Neligan/Prudham normsBlue shows children from Dawn House School- NB severe SLIOnly 12% of SLI had first words before 18 months

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http://www.johnbercow.co.uk/23012007_disabled_children

• I believe that we suffer continually in this country from a problem of late assessment, late identification and late diagnosis. ….

• I believe that sometimes those operating the system play precisely upon the hopes, as well as the more exaggerated fears, of some parents by saying, “Don’t worry. There’s plenty of time.” Of course, those who are articulating that message very often have a reason of financial self-interest for holding back the

provision of what is needed.

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Most children who have SLI were late talkers, ≠ most late talkers will have SLI

Key issue of ‘base rates’

Consider population of 1000 children• In whole population, 10% are late talkers = 100

cases• Suppose 3% of children have severe SLI

In population of 1000, will be 30 cases of severe SLI88% of severe SLI were late talkers (i.e. first words after 18 months), = 26 cases

• So only 26/100 late talkers will have severe SLI

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But many children do ‘grow out of it’: Late bloomers

Fischel et al (1989)

•26 2-year-olds who “understood complete sentences but who could say only a few words.”

•Followed after 5 monthsApprox 1/3 no improvement1/3 mild improvement1/3 in the normal range

The phenomenon of the ‘late bloomer’

Fischel, J. E., Whitehurst, G. J., Caulfield, M. B., & Debaryshe, B. (1989). Language growth in children with expressive language delay. Pediatrics, 83, 218-227.

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General agreement: early intervention better than late

• Failure to intervene may lead to development of secondary problems

• Also, notion of brain plasticity

• Easier to modify brain development before neural pathways are committed

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Effectiveness of occlusion by age

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eBrain plasticity example:

eye-patching (occlusion) for ‘lazy eye’

Epelbaum, M. et al (1993). The sensitive period for strabismic amblyopia in humans. Ophthalmology, 100(3), 323-327.

In vision, much better outcome of treatment if done early in life

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Is there a “sensitive period” for language

Adults tested on grammaticality judgement task, e.g. judge correct/incorrect:The man allows his son to watch TVThe man allows his son watch TVThe man lets his son to watch TVThe man lets his son watch TV

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native 3 to 7 8 to 10 11 to 15 17 to 39

Age at arriving in US

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reEvidence from ‘natural experiments’, e.g. ultimate skill of second language learners much better for those who came to new country before 10 yr old

Johnson, J. S., & Newport, E. L. (1989). Critical period effects in second language learning: the influence of maturational state on the acquisition of English as a second language. Cognitive Psychology, 21, 60-99.

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The quandary

• Late intervention– Children develop secondary problems – May be less effective than earlier

• Early intervention:– Risk of intervening with children who are just

‘late bloomers’ – wasted resources– May create problems in the child

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What is needed

• Some way of distinguishing ‘late bloomers’ from those with more persistent problems

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How to find out?

• Need studies that start with late talkers and follow them up

• At follow-up, divide into those who have resolved and those with persistent problems

• Then look at time 1 data and see if we could have distinguished them

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What factors likely to affect outcome?

• Home environment*

• Birth risk*

• Genetic risk*

• Severity of language delay

• Profile of language difficulties

* Predictors of late talking in study by Zubrick, S. R., et al (2007). Late language emergence at 24 months: An epidemiological study of prevalence, predictors, and covariates. Journal of Speech, Language and Hearing Research, 50(6), 1562-1592. doi: 10.1044/1092-4388(2007/106)

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Our study: the children

• Recruited from a database of families from local maternity ward and local toddler groups.

• Mothers filled in Oxford University Communicative Development Inventory (OCDI) when child 18-19 mo old: long list of words – parent indicates if child says word and understands it, or just understands, or neither

Bishop, D. V. M., Holt, G., Line, E., McDonald, D., McDonald, S., & Watt, H. (2012). Parental phonological memory contributes to prediction of outcome of late talkers from 20 months to 4 years: a longitudinal study of precursors of specific language impairment. Journal of Neurodevelopmental Disorders, 4(3). doi: 10.1186/1866-1955-4-3

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Section of OCDI

understandsand says

understands

Total OCDI has 416 words; At 18 months, bottom 15% say <= 10 words

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The children

• 26 late talkers: expressive OCDI more than 1 SD below the mean (<= 10 words)

• 70 average talkers: OCDI from 20th to 75th centile • Aimed to include children with a family history of

speech/language problems– defined as having 1st degree relative with history of receiving

intervention for language or reading problems

• Child seen for a language and cognitive assessment

• 24 late talkers and 59 average talkers available for follow-up at 4 yr.

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Assessment at 20 months

• Vineland Adaptive Behavior Scales, 2nd edition (VABS) – Parental interview used to evaluate the child's

development in the areas of Communication, Socialisation, Daily Living, and Motor Skills.

• Mullen Scales of Early Learning– Child-based assessment that provides scores for

Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language skills.

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Assessment at 20 months

• Mullen Scales of Early Learning– Child-based

assessment that provides scores for Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language skills.

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Assessment at 4 years

• Nonverbal Ability• Expressive and receptive language• Parental report of communication skills

Also brief assessment of parental language (done when child 20 months and 4 years – just one parent, usually the mother)

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Classification at 4 yrs

• Typical development (TD): Normal range nonverbal ability and no more than one impaired language measure

• Specific language impairment (SLI): impaired on at least two language measures, with normal nonverbal ability

• In addition, 7 children with below average nonverbal ability – not considered further

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Predicting outcome for individual children

Best prediction of 4 yr outcome from:• Child’s language at 20 months + family history +

parent nonword repetition;

Prediction was better than chance, but far from perfect

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Clinical prediction for individual children

Simple rules of thumb from our data:

High risk of persistent language problems if:

+ Family history and mother scores more than 1 SD below average on nonword repetition test.

OR

No family history but Vineland communication is below 85 (1 SD below mean)

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Other factors to consider

Thal et al (1991) • Poor outcome specifically in those with poor

comprehension/gesture

Our study

• Comprehension measures did not add much to prediction but our sample had few children with poor comprehension at 18 months

• Have not yet analysed measures of gesture

Thal, D. J., Tobias, S., & Morrison, D. (1991). Language and gesture in late talkers: a one-year follow-up. Journal of Speech and Hearing Research, 34, 604-612.

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Summary

• Majority of late talkers did not have later language difficulties

• Having a family history of language/literacy problems is a risk factor for persisting problems

• Poor comprehension or lack of gesture may also be important predictors

• Parental report on Vineland can also help identify those likely to need help

• Appropriate to adopt ‘watchful waiting’ strategy with late talkers who have good comprehension and don’t have family history of language problems