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. 2018 Oct 15;2018(10):CD012089. doi: 10.1002/14651858.CD012089.pub2

Kaiser 2013.

Methods Design: RCT
Participants Location: Tenessesse, USA
Setting: 'clinic' location not specified, home sessions in participants' homes
Child participants
Sample size: 77 children with intellectual disability, 18 of whom had Down syndrome (intervention: 8, control: 10)
Mean age: not reported (range 30‐54 months)
IQ: intervention: mean 67 (SD 8.35), control: mean 68.5 (SD 7.65)
Inclusion criteria

  1. Nonverbal IQ between 50 and 80

  2. Total language standard score less than the 11th percentile on the Preschool Language Scale ‐ 4th Edition

  3. MLU between 1.00 and 2.00

  4. At least 10 productive words

  5. Ability to verbally imitate 7 of 10 words during an imitation screening task

  6. Normal hearing

  7. English as the child's primary language

  8. Child's primary caregiver was willing to be trained as part of the intervention procedures


Comorbid conditions: none reported
Number of children per family: not reported
Parent participants
Sample size: 18 parents (1 father (in the intervention group), 17 mothers)
Mean age: intervention: 42.3 years, control: 39.8 years, range 30‐50 years across both groups
Education: 3 parents had a master's degree, 8 a a bachelor's degree, 1 up to 3‐years of college, 2 up to 2‐years of college, 3 a high‐school level education, and 1 did not specify.
Marital status: not reported
Occupation: 9 participants were homemakers, with 8 (including the 1 father) being employed on a part‐ or full‐time basis, and 1 person did not specify
Socioeconomic status: not reported, but see 'education' and 'occupation' directly above
Interventions The 18 participants were randomly assigned to 1 of 2 groups:

  1. Intervention group (n = 8):enhanced milieu teaching (EMT), delivered by a clinician and parents trained by a clinician, in both home and clinic settings. 3 sessions were carried out each week for 12 weeks (twice a week for 12 weeks in a clinic setting for 30 minutes (24 sessions) and once a week at home for 20 minutes (12 sessions)). In addition, parents had 1 × 2‐3 hour workshop that included information on EMT intervention. The total intervention time was approximately 19 hours.

  2. Control group (n = 10): clinician‐delivered EMT sessions only, in a clinic setting. Participants in the therapist‐only EMT (EMT‐T) group received 36 intervention sessions; similar to individual EMT intervention sessions (24 clinic and 12 home)


Most children in the intervention and control groups continued to receive regular community‐based speech‐language therapy during the study, as well as other special education services.
Outcomes The measures listed below were used to measure the outcomes immediately postintervention, 6 months postintervention and 1 month postintervention.

  1. Peabody Picture Vocabulary Test‐III

  2. Expressive Vocabulary Test

  3. Preschool Language Scale – 4th edition (auditory comprehension; expressive communication and total language scales)

  4. MLU in words (MLUw), number of different words (NDW) and Index of Productivity of Syntax (IPSyn) as measured from videotaped interaction of free play with an adult who did not prompt the child

  5. MacArthur Communicative Development Inventory

  6. Milieu Teaching Project KidTalk Code was used for the children to measure the number of unique targets produced, percentage of child utterances that contained any of the child language targets, MLUw and NDW in both trained and untrained activities with their parents

  7. Milieu Teaching Project KidTalk Code was also used for the parents to measure their responsive interaction, percentage of language modelling, expansions and milieu teaching prompts in both trained and untrained activities

  8. Parenting Sress Index


The study measured adherence to the intervention by the clinician, although parental dosage (intervention fidelity) was not reported.
Notes Study start and end dates: not reported
Funding source: this study was supported, in part, by the National Institute of Child Health and Human Development (grant HD45745) and by the Department of Education (grant H325D070075).
Conflicts of interest: not reported
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Comment: children were randomly assigned to 1 of 2 experimental conditions using an automated, randomisation computer programme after the child qualified for the study.
Allocation concealment (selection bias) Unclear risk Comment: did not report if this was conducted
Blinding of participants and personnel (performance bias) 
 All outcomes High risk Comment: not possible
Blinding of outcome assessment (detection bias) 
 All outcomes High risk Comment: administration and scoring of norm‐referenced assessments were completed by staff members who were not blind to the experimental condition.
Incomplete outcome data (attrition bias) 
 All outcomes Low risk Comment: although there were missing data, the reasons were unlikely to be related to the true outcome, and they were balanced across groups.
Selective reporting (reporting bias) Low risk Comment: reported all pre‐specified outcomes
Other bias Low risk Comment: appears to be free of other sources of bias