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Overcoming social disadvantages through reinforcement of babble in infants from low socioeconomic homes
Last registered on June 19, 2020

Pre-Trial

Trial Information
General Information
Title
Overcoming social disadvantages through reinforcement of babble in infants from low socioeconomic homes
RCT ID
AEARCTR-0005552
Initial registration date
June 19, 2020
Last updated
June 19, 2020 11:24 AM EDT
Location(s)

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Primary Investigator
Affiliation
University of York
Other Primary Investigator(s)
PI Affiliation
University of York
PI Affiliation
James Madison University, VA, USA
PI Affiliation
University of York
Additional Trial Information
Status
In development
Start date
2020-09-01
End date
2022-11-30
Secondary IDs
SRG19\190697 (Funder: British Academy)
Abstract
Babble is the consonant-vowel syllabic vocalisations (e.g., ‘dadada’) produced by infants typically from 7 months of age and is the precursor to spoken language. Whilst early babbling and first word production are known to be related, a causal relationship has not yet been experimentally established. This project will address this through a new intervention aimed at infants from lower-SES families.
Such infants are at risk for slower-than-typical early word production. It is well established that children from such families have much less adult speech addressed to them than children from middle-SES families, and their language on entering nursery/reception is less advanced than that of children from middle-SES families. We suspect that the lower exposure to speech in those infants begins in their first year – low-SES-infants’ babble receives fewer adult responses contingent on their vocalisations at age 11 months than does that of middle-SES infants and they engage in fewer verbal interactions with adults and vocalise less than middle-SES infants, even though they begin babbling at a similar age.
The intervention will be delivered using an iPad game (BabblePlay) which we have designed, that rewards infants with moving shapes appearing on the screen when they vocalise.The app responds to voiced infant utterances in real time with colourful moving shapes, providing reinforcement to all vocalisations within an infant’s pitch range that are not too loud (so as not to encourage shouting and crying). It does not respond to environmental sounds such as bangs, rustling and traffic noise.
We predict that infants who have used BabblePlay will have larger vocabularies than those who have not, and that their parents’ attitudes towards talking to infants will become more favorable as a result.
External Link(s)
Registration Citation
Citation
Daffern, Helena et al. 2020. "Overcoming social disadvantages through reinforcement of babble in infants from low socioeconomic homes." AEA RCT Registry. June 19. https://doi.org/10.1257/rct.5552-1.0.
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Experimental Details
Interventions
Intervention(s)
We will recruit 7-month-old infants from low SES families in the York area. Infants will be randomly divided into two groups: Infants in the experimental group (n = 42) will receive the BabblePlay app to use in the home for 3 weeks. The control group (n = 42) will receive an app that does not respond to voice, but only to touch (shapes will disappear when touched).
We will follow the two groups until the infants are 16 months old.
Intervention Start Date
2020-09-01
Intervention End Date
2022-08-31
Primary Outcomes
Primary Outcomes (end points)
1) Productive lexicon size at 16 months, assessed based on the 'The UK Communicative Development Inventories' (Alcock, Meints & Rowland, 2020) - using short form
Primary Outcomes (explanation)
1) Productive lexicon size at 16 months: Number of words ticked by parents as "understood and said" by the infant on the latest filled-in Inventory, around age 16 months.
Power analysis was based on Arriaga et al. (1990), who compared lexicon sizes between low-SES and middle-SES children (proxies for our Control and Experimental groups, respectively) based on their Productive Lexicon scores on a similar questionnaire (the one Arriaga et al. used was intended for US children aged 16-30 months, and we are using a 2020 adaptation for UK English for ages 8-18 months). Effect size in the Arriaga et al. paper was 0.54 or 0.76 (using raw or percentile scores, respectively). We will use a mid-way effect size of 0.65. This translates to a sample size of N = 80, assuming significance level = 0.05 and power = 0.8. To allow for 5% attrition we will recruit 84 participants.
We can use both raw scores and percentile scores, as did Arriaga et al. Arriaga et al. used the full-length questionnaire. We will use a short version, for which norms are also available. The correlation between Production vocabulary scores on the long and short forms is reported as being Pearson's r = .96 (Alcock, Meints & Rowland, 2020).
Secondary Outcomes
Secondary Outcomes (end points)
2) Receptive lexicon size at 16 months, assessed based on the 'The UK Communicative Development Inventories' (Alcock, Meints & Rowland, 2020) - using short form
3) Productive lexicon trajectory between 7 to 16 months, assessed based on the 'The UK Communicative Development Inventories' sort form (Alcock, Meints & Rowland, 2020)
4) Receptive lexicon trajectory between 7 to 16 months, assessed based on the 'The UK Communicative Development Inventories' short form (Alcock, Meints & Rowland, 2020)
5) Change in parental attitudes between 7 and 16 months, based on the Kennison & Byrd-Craven 2015 parent belief questionnaire.
6) Average number of vocalisations (or maximal number of vocalisations) per session in the three final days of use (maximal number of 6 sessions, at 2 per day for 3 days), based on the vocalisation counts as recorded by the two apps.
7) Change in the number of vocalisations over time, based on the counts of the two apps, as recorded over the entire 3-week period in which each infant uses it.
8) Score at 16 months on the subtest of the motor skills section from the Vineland Adaptive Behavior Scale.
9) Trajectory of change from 7 to 16 months on the subtest of the motor skills section from the Vineland Adaptive Behavior Scale.
Secondary Outcomes (explanation)
2) Receptive lexicon size at 16 months: Number of words ticked by parents as "understood" by the infant on the latest filled-in Inventory, around age 16 months.
3) Productive lexicon trajectory between 7 to 16 months: Based on number of words ticked by parents as "understood and said" by the infant on the filled-in Inventories from ages 7, 8, 9, 10, 11, 12 and 16 months.
4) Receptive lexicon trajectory between 7 to 16 months: Based on number of words ticked by parents as "understood" by the infant on the filled-in Inventories from ages 7, 8, 9, 10, 11, 12 and 16 months.
5) Change in parental attitudes between 7 and 16 months: There are 14 itmes in the questionnaire, which parents score using a 7-point scale (1 = strongly disagree, 7 = strongly agree). In the analysys releavent items' scores will be reversed. Items are grouped into three composite variables: Beneficial Beliefs (items 1, 3, 6, 9, 11, and 14), Passive Infant (items 2 and 8), and Family (items 12 and 13). Average score per each composite variable at each age will be computed and the difference between them calculated.
6) Average number of vocalisations (or maximal number of vocalisations) per session in the three final days of use (maximal number of 6 sessions, at 2 per day for 3 days), based on the vocalisation counts as recorded by the two apps: Each time an infant uses either app, the app records the number and duration of vocalisations. These counts (not the duration) will be used. If a family uses the app less than 6 times over a period of 3 days, we will use the latest 6 sessions as long as these are not spread over more than 5 days. If they are, we will base the measurement on the number of sessions available from the last 5 days. If not all sessions terminate at 5 minutes, we will extrapolate the number of vocalisations to 5 minutes' duration.
7) Change in the number of vocalisations over time, based on the counts of the two apps, as recorded over the entire 3-week period in which each infant uses it.6) Change in the number of vocalisations over time, based on the counts of the two apps: Each time an infant uses either app, the app records the number and duration of vocalisations. These counts (not the duration) will be used.
We will consider removing from the study families who use the app too infrequently (where the definition of 'too infrequently' will depend on the distribution of number of sessions found within the groups.
8) Score at 16 months on the subtest of the motor skills section from the Vineland Adaptive Behavior Scale: The scale is scored on a scale of 0 (never) to 4 (almost always) and assesses both gross and fine motor development. Parents/carers will fill the questionnaire. The items relevant to the skills which the ReachToTouch app may help to develop will be used to create a subset which measures advance in object manipulation, reaching, catching ball, etc. The total score on the subset will be used.
9) Trajectory of change from 7 to 16 months on the subtest of the motor skills section from the Vineland Adaptive Behavior Scale. The trajectory of total scores on the subset (described in 8 above) from age 8 to 15 months will be used.
Experimental Design
Experimental Design
Apart from the difference between the apps, the procedures and measures taken will be identical for the two groups.
During the initial 3 weeks infants will use the apps twice a day (or as close as possible to that). The apps work for 5 minutes at a time and then turn themselves off.
Following those first 3 weeks, participation will involve filling in questionnaires periodically (about general development, reaching development and language development), until the child turns 16 months.
Experimental Design Details
Not available
Randomization Method
Block randomisation will be done by the PI in the office using the "rand()" command in Excel.
The project administrator will not be blind to the group that participants are assigned to, since she will need to give each family an iPad with the correct app on it and to teach the family to use it.
Randomization Unit
Individual.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
0
Sample size: planned number of observations
84 infants.
Sample size (or number of clusters) by treatment arms
42 infants in Experimental group, 42 infants in Control group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Power analysis was based on Arriaga et al. (1990), who compared lexicon sizes (based on an earlier version of the CDI) between low-SES and middle-SES children (proxies for our Control and Experimental groups, respectively). Effect size was 0.54 or 0.76 (using raw or percentile scores, respectively). We will use a mid-way effect size of 0.65. This translates to a sample size of N = 80, assuming significance level = 0.05 and power = 0.8. To allow for 5% attrition we will recruit 84 participants.
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Language and Linguistic Science Ethics Committee, University of York
IRB Approval Date
2020-05-02
IRB Approval Number
N/A