Overcoming social disadvantages through reinforcement of babble in infants from low socioeconomic homes

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.

2020-09-01

2022-08-31

1) Productive lexicon size at 16 months, assessed based on the 'The UK Communicative Development Inventories' (Alcock, Meints & Rowland, 2020) - using short form

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).

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.

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.

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.

Procedure:
During months 1-16 of the project, York's Children's Centres' staff will give eligible parents/carers a flyer describing the study when their infants are 4-7 months old. Parents interested in taking part will contact us. The infants will be randomly divided into the two groups.
Parents will be asked to use the apps twice a day, for 5 minutes at a time, for 3 weeks. The Control app (ReachToTouch), like BabblePlay, shuts down automatically after 5 minutes and audio-record the infants while they are interacting with the app. The project administrator will be based in York's Children’s Centres for several hours once a week, and will meet the families (in the Children’s Centre or in their homes) when their child turns 7 months to give them the iPad and explain how to use the app, and again at the end of the 3 weeks to pick the Pad up and explain the next stage of involvement. When a family finishes using the app, after the three week period, the iPad will be wiped clean of any data that was on it, reset to factory settings, the app will be uploaded onto it, and then the iPad will be lent to the next family to use.
The project administrator will phone families regularly and hold a ‘surgery hour’ in the Children’s Centres, to answer queries and ensure engagement with the research.
Throughout the participation period, families will also fill in electronic questionnaires, which will be sent as links to their phones:
1) Parental attitude and belief questionnaire regarding the benefits of talking to infants (Kennison & Byrd-Craven, 2015) (twice over the period of participation, at months 7, 16).
2) Virtual developmental diary (10-item tick-box-based ) to record the infant’s developmental milestones (following Ellis-Davies, Sakkalou, Fowler, Hilbrink & Gattis, 2012; see Supplementary Documents) (weekly, months 7-12).
3) Electronic vocabulary checklist (CDI: The UK Communicative Development Inventories [Alcock, Meints & Rowland, 2020]) (monthly, months 7-12, plus one-off in month 16).
4) Vineland Adaptive Behavior Scale - A subset of the motor skills section (monthly, months 7-12, plus one-off in month 16).
Once every 3 months the project administrator will hold a ‘graduation party’ for infants who have finished their participation period to give the families a final token of thanks for their participation and to help with final questionnaire filling for those who have not filled them in.

Each family will thus be actively involved in the research for 9 months, as follows:
Tasks for families to perform
Age (months)
Task 7 8 9 10 11 12 16
App (BabblePlay or ReachToTouch) twice daily for 3 weeks -- -- -- -- -- --
Parental attitude and belief questionnaire ✔ -- -- -- -- -- ✔
Virtual developmental diary (on app, then sent to phone) weekly weekly weekly weekly weekly weekly --
Electronic vocabulary checklist (CDI) ✔ ✔ ✔ ✔ ✔ ✔ ✔
Vineland Adaptive Behavior Scale subtest ✔ ✔ ✔ ✔ ✔ ✔ ✔

Planned meeting/phone conversation between project administrator and families
Purpose
Age of baby (months) Project administrator action Face to Face (F2F) or phone (Ph) All families or by choice, as needed?
7 Bring iPad to family, explain how to use Face to Face All
7 + 3 weeks Pick up iPad from family, explain next stage Face to Face All
Monthly, age 7-12 Check engagement, ask if any problems Phone All
Weekly - throughout project Hold ‘surgery hours’ - for queries and support Face to Face As needed
As needed Visit families who are not engaging Face to Face As needed
16-18 months Run ‘graduation party’ to help parents with final form filling and to give token of thanks for participation Face-to-face in group All

Data and sound files collected by the iPad will be emailed to the researchers via the iPad, and saved on a secure University of York server, together with the questionnaire data sent via participants’ phones.
The developmental diary entries will be used to control for non-verbal development in the sample.
Families will be paid £30 after the initial 3-week period, another £20 at 12 months after filling in the monthly questionnaires and another £20 at 16 months after filling in the final questionnaires. In total each family will receive £70 if they fully engage with the study.

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.

Individual.

No

0

84 infants.

42 infants in Experimental group, 42 infants in Control group.

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.