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There is an increasing awareness among
pediatricians on the role of the
environment in mental and cognitive
development. Early stimulation programs
were developed that targeted preservation of the
mother-infant relationship, improved stimulation for
preterm infants and reduced stress in the neonatal
nursery(1). By early “infant stimulation” we mean
early interventional therapy for babies at-risk for
developmental delay. Developmental deficits occur
among babies with genetic and metabolic disorders,
environmental risk factors and biological risk factors
like low birth weight(2). Infants born low
birthweight (<1800g) to disadvantaged mothers are
at developmental risk for both biological and social
reasons(3).
Meta-analysis of early intervention efficacy
studies has shown that early intervention is effective
in improving the developmental status, although
there is no uniform agreement as to whether the
effects last long(4). A recent Cochrane review of
sixteen studies has shown that early intervention
programs for preterm infants have a positive
influence on cognitive outcomes in the short to
medium-term(5). Long-term developmental follow-
up of at-risk babies in the community, supported by
early intervention therapy needs to be established, as
shown by the experience in the developed
countries(6). Large community early stimulation
programs have shown that efficacy was greatest with
programs involving both the parents and the baby;
long-term stimulation improved cognitive outcomes
INDIAN PEDIATRICS S20 VOLUME 46, SUPPLEMENT, JANUARY 2009
Results: The intervention group of babies had a
statistically significant higher score for mental
developmental index (MDI) and psychomotor
developmental index (PDI) at one and two years of age.
After adjusting all significant risk factors for development,
the babies who had intervention had significantly higher
Bayley scores, 5.8 units at one year and 2.8 units at two
year, as compared to control babies.
Conclusion: Early stimulation therapy was effective at
one year. The beneficial effect also persisted at two years,
without any additional interventions in the second year.
Key words: At-risk neonates, Child development, Early
stimulation, Intervention, MDI, PDI.
Objective: To study the effectiveness of Child
Development Centre (CDC) model early stimulation
therapy done in the first year of postnatal life, in improving
the developmental outcome of at-risk neonates at one and
two years of age.
Design: Randomized controlled trial.
Setting and subjects: The study participants included a
consecutive sample of 800 babies discharged alive from
the level II nursery of Medical College,
Thiruvananthapuram.
Intervention: The control group received routine postnatal
check-up as per hospital practice. Intervention group in
addition received CDC model early stimulation therapy
(home-based).
Effect of Child Development Centre Model
Early Stimulation Among At-risk Babies –
A Randomized Controlled Trial
MKC NAIR, ELSIE PHILIP, L JEYASEELAN, BABU GEORGE, SUJA MATHEWS AND K PADMA
From Child Development Centre, Medical College, Thiruvananthapuram 695 011, Kerala, India.
Correspondence to: Dr MKC Nair, Professor of Pediatrics and Clinical Epidemiology, and Director,
Child Development Centre, Medical College, Thiruvananthapuram 695 011, Kerala, India.
E-mail: nairmkc@rediffmail.com
L E A D A R T I C L E
INDIAN PEDIATRICS S21 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
and child-parent interactions, cognition showed
greater improvements than motor skills and, larger
benefits were obtained in families that combined
several risk factors(7).
In India, it has been shown that early intervention
program can be successfully conducted through the
high risk clinic approach(8). But, before a national
policy is evolved in this regard, a randomized
controlled trial showing efficacy of early inter-
vention is mandatory. Hence this randomized
controlled trial was conducted to study the effective-
ness of Child Development Centre (CDC) model
early stimulation therapy, done in the first year of
postnatal life, in improving the developmental
outcome among at-risk babies.
METHODS
The study was conducted at the level II neonatal
nursery of Sree Avitam Thirunal (SAT) hospital and
follow-up was done at CDC, Medical College,
Thiruvananthapuram (Fig. 1). The entry criteria
included; born in SAT hospital, admitted to level II
neonatal nursery, discharged alive and, informed con-
sent for follow-up and early stimulation. No exclu-
sion criteria were used, so as to give generalisability
to the results obtained. A pilot study on a sample of
100 babies was done to make sure that the randomiza-
tion procedure, early stimulation, outcome measure-
ments and blinding proceeded as planned.
Sample Size: As this was designed as a pragmatic
clinical trial, the study participants included a
consecutive sample of 800 babies discharged alive,
with no exclusion criteria. A sample size of 336 in
each group was obtained, which was adequate to
detect between groups, 4 clinically significant
mental developmental index (MDI), using Bayley
1046 Admitted to special care nursery
142 Death during hospital stay
100 Pilot study
4 Moving out of state immediately
800 Randomized
400 Allocated to intervention 400 Allocated to control
76 Lost to follow-up 59 Lost to follow-up
324 Analyzed at 1 year 341 Analyzed at 1 year
358 Analyzed at 2 year 377 Analyzed at 2 year
FIG. 1 Participant flow in the study.
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INDIAN PEDIATRICS S22 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
scales of infant development (BSID) with alpha error
of 5% and beta error of 20%. A difference of 4 in the
MDI scores was taken as clinically significant
difference because it is same as ¼ standard deviation
on Bayley scales, after normalisation of the raw
scores to scores with a mean of 100 and standard
deviation of 16 as explained in the Bayley
manual(9,10). Allowing for 20% loss to follow-up, a
total of 800 eligible subjects, who met all the
inclusion and exclusion criteria were randomised to
intervention and control group on the day of
discharge.
Randomization and allocation: Simple
randomisation was done using RALLOC software.
Serially numbered opaque envelops containing the
allocation details of a subject were developed at the
Department of Biostatistics, Christian Medical
College, Vellore. The control group received the
routine postnatal check-up as per hospital practice
and the intervention group, in addition, received
CDC model early stimulation therapy(11). CDC
model early stimulation aims at stimulating the child
through the normal developmental channel,
prevention of developmental delay, prevention of
asymmetries and abnormalities, detection of
transient tone abnormalities and minimization of
persistent tone abnormalities. The four major
sensory modalities used are; visual stimulation,
auditory stimulation, tactile stimulation and
vestibular-kinaesthetic stimulation. An occupational
therapist at CDC, trained the mothers individually
and in groups, to give CDC model early stimulation
and the mothers continued to do the same at home.
The compliance was assessed during monthly
follow-up visits by observing the ease with which the
mother did the early stimulation. Compliance score
was derived from a structured questionnaire
designed for this purpose, with a total score of 35,
any score below 31 was taken as poor compliance
and above 31 as good compliance.
Outcome measurements were made at one and
two years of age by an observer blind to the treatment
status of the babies. These included MDI, PDI and
Bayley score derived as per the Bayley manual. The
Bayley scores represent the motor and mental raw
scores together and, MDI and PDI represent the
deviation quotients for mental and motor scores,
respectively. Anthropometric measurements of
weight, length and head circumference were
measured as per standard procedure. Those who did
not report for one-year assessment were contacted
individually at home before the second-year
assessment.
Quality check of the data collected was done by
perusal of individual data sheets and random
checking of about 10% of the admission record
sheets by the principal investigator. Data were
entered and analysed using Foxplus, and SPSS PC+
softwares. For continuous outcome, Student’s t-test
was used to compare the means in the two groups.
Student’s t-test and two-way analysis of variance
were used to compare the means of the study
variables between intervention and control group. A
95% confidence interval for the true difference in
means was also calculated. For multivariate analysis,
the study variables, which were significant at 10%
level of significance in bivariate analyses, were
considered. Stepwise multiple regression analysis
was done separately for MDI, PDI and Bayley scores
at the end of first and second year. Significance of the
regression model was obtained by F test. R2
was also
computed. Wald test was used to identify the
significance of the variables included in the model.
The ethical committee of Medical College,
Trivandrum provided the ethical clearance for the
study.
RESULTS
A total of 1046 babies, born in SAT hospital were
admitted to the level II neonatal nursery during the
study period. Out of these 142 babies died in the
nursery, 100 babies were used for the pilot study and
4 babies planned to move outside the state and hence
could not participate in the study. Outcome
measurements were available at the end of one year
for 665 babies excluding 135 lost to follow-up, and
at the end of second year for 735 babies excluding 65
lost to follow-up. Table I shows that the baseline
variables are equally distributed in both arms. Nearly
one third of the mothers studied up to middle school.
Of the children studied, nearly 27% were preterm
and 50-55% of the babies were born with low birth
weight. Nearly one fourth of them were SGA.
Table II shows one year and two-year outcomes by
INDIAN PEDIATRICS S23 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
intervention and control groups. There was a
statistically significant difference observed with the
intervention group having a higher score for MDI,
PDI, Bayley score and length both at one year and
two year.
After converting the raw mental, motor and
Bayley scores at 1 year and 2 years to percentile
rankings, using tables in the Bayley manual, the
same was compared between intervention and
control group. Percentile ranking position 1 denotes
lowest raw scores group (<3rd percentile) and rank 5
denotes highest raw score group (>50th percentile).
The proportion of babies with rank 1 was higher in
the control groups and less in the intervention groups
for one year and 2 year motor and mental scores. On
the other hand, the proportion of babies with rank 5
was higher in the intervention groups and less in the
control groups for one year and 2 year motor and
mental scores. These differences observed were
statistically significant. In the intervention group, the
mean SD of 1 year and 2 year MDI, PDI and Bayley
scores were compared by the compliance score
derived from a structured questionnaire, below 31
denoting poor compliance for home intervention
program and above 31 denoting good compliance.
It was observed that as the compliance score
increased, there was a statistically significant
increase in the MDI, PDI and Bayley scores, both at
1 and 2 years.
Multiple regression analysis of the study
variables for the outcome measure of Bayley scores
at 1 and 2 year was done separately. Normal
birthweight babies had a significantly higher Bayley
score, 5.6 units at one year and 6.2 units at two year,
as compared to low birthweight babies. Babies who
did not have neonatal seizures had a significantly
higher Bayley score, 7.9 at one year and 9.9 at two
year. Babies who did not have intrauterine infection
had significantly higher Bayley score, 10.8 units at
one year and 11.7 units at two, as compared to others.
After adjusting all these significant risk factors for
development, the babies who had intervention had
significantly higher Bayley scores, 5.8 units at one
year and 2.8 units at two year as compared to control
babies. The regression models were statistically
significant both at 1year (R2 = 15.0%, P<0.0001)
and at 2 years (R2 = 18.7%, P<0.0001). Table III
TABLE I STUDY VARIABLES AT BASELINE
Study variable Intervention Control
n (%) n (%)
Residence: Rural 298 (74.5) 324 (81.0)
Religion
Hindu 304 (76.0) 278 (69.5)
Muslim 56 (14.0) 55 (13.8)
Christian 40 (10.0) 67 (16.8)
Male sex 217 (54.3) 221 (55.3)
Caste
SC/ST 33 (8.4) 42 (10.6)
Others 360 (91.6) 356 (89.4)
Education of father
Middle school 130 (32.8) 130 (33.0)
High school 266 (67.2) 264 (67.0)
Education of mother
Middle school 125 (31.6) 134 (33.9)
High school 271 (68.4) 261 (66.1)
Occupation of father
Irregular job 181 (46.3) 198 (50.5)
Employed 210 (53.7) 194 (49.5)
Occupation of mother
Not employed 352 (90.7) 354 (90.8)
Employed 36 (9.3) 36 (9.2)
Families with 1 child 111 (29.0) 108 (28.4)
Monthly income
Low 266 (68.4) 272 (69.9)
High 123 (31.6) 117 (30.1)
Nuclear family 98 (25.6) 115 (29.8)
Joint family 285 (74.4) 271 (70.2)
Birth order >1 174 (44.6) 161 (41.4)
Consanguinity 39 (9.8) 37 (9.4)
High risk pregnancy 133 (33.6) 134 (33.6)
Assisted delivery 169 (42.5) 178 (44.5)
Fetal distress 70 (17.7) 70 (17.7)
Intrauterine infection 4 (1.0) 8 (2.0)
Pre-term 108 (27.1) 111 (27.8)
Birthweight <2500g 202 (50.8) 217 (54.3)
SGA baby 94 (23.7) 97 (24.3)
Asphyxia
Mild 86 (28.8) 106 (26.5)
Moderate 10 (3.3) 16 (4.0)
Normal 203 (67.9) 278 (69.5)
Neonatal seizures 17 (4.3) 20 (5.0)
Respiratory problems 65 (16.3) 62 (15.5)
Meningitis 3 (0.8) 2 (0.5)
CNS Malformation 2 (0.5) 2 (0.5)
Chromosomal anomaly 2 (0.5) 2 (0.5)
INDIAN PEDIATRICS S24 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
TABLE II MEAN AND SD OF OUTCOME AT O NE Y EAR AND TWO Y EAR
Mean SD Mean SD P value 95% CI
Intervention Control
(n=324) (n=341)
One Year
MDI 83.6 13.7 78.5 13.3 <0.001 3.05, 7.15
PDI 90.9 18.1 83.7 18.2 <0.001 4.44, 9.96
Bayley Score 87.3 14.1 81.1 14.2 <0.001 4.05, 8.35
Weight (kg) 8.1 1.0 7.9 1.0 <0.001 0.17, 0.32
Length (cm) 72.5 2.9 72.1 3.0 0.035 2.40, 4.39
Head circumference 44.4 2.3 44.3 1.7 0.580 –0.206, 0.406
Two Year Intervention Control
(n=358) (n=377)
MDI 83.1 13.9 80.3 13.4 <0.005 0.83, 4.77
PDI 99.9 15.6 95.8 16.6 <0.005 1.77, 6.43
Bayley Score 91.5 13.0 88.0 13.7 <0.005 1.57, 5.43
Weight (kg) 10.3 1.4 10.1 1.3 0.089 0.005, 0.39
Length (cm) 83.5 3.6 82.4 5.2 0.002 0.45, 1.75
Head circumference 46.1 1.8 46.3 1.7 0.173 -0.45, 0.05
TABLE III BAYLEY SCORES AT THE A GE OF ONE Y EAR AND TWO YEAR
Intervention Control
Mean SD N Mean SD N
Bayley score (1 year)*
Below 1500g 83.8 12.0 38 75.3 13.2 36
1501 – 2000g 83.0 16.6 65 80.5 15.0 67
2001 – 2500g 84.4 13.4 66 76.7 13.8 71
2501 – 3000g 91.2 12.9 100 84.2 13.1 109
3001 and above 91.0 12.4 54 85.0 14.0 58
Bayley score (2 year)
Below 1500g 89.1 13.7 43 81.9 13.6 43
1501 – 2000g 88.0 13.5 75 86.5 14.5 82
2001 – 2500g 87.9 14.1 71 85.1 13.3 80
2501 – 3000g 94.5 10.6 109 91.9 11.9 110
3001 and above 96.4 11.9 59 91.2 14.9 61
* P value <0.001
shows that for an increase of every 500 grams, there
is a significant and consistent increase in mean
values of Bayley scores, both at one year and two
year. Similarly, in every birth weight group, the mean
values were higher for the intervention group and
these differences were statistically significant.
Similar findings were observed for MDI (P=0.005),
PDI (P=0.001), and length (P=0.002), but not for
head circumference (P=0.171) and weight
(P=0.090).
INDIAN PEDIATRICS S25 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
DISCUSSION
In spite of a long history of mandatory provision of
early intervention programs for at-risk infants in
USA, there are still a few, who genuinely doubt the
usefulness of massive state funding for early
intervention programs(12). The term family-centred
early intervention refers to both a philosophy of care
and a set of practices, as both have been used to guide
research, training and service delivery(13).
Although, there is no uniform agreement as to the
ideal group of babies who would benefit maximally
from early intervention, the neonatal nursery
graduates would probably form the best captive
population for providing early stimulation.
The sample size estimated was a total of 672 and
we have outcome measurements for 665 babies at
one year and 735 babies at two year. In spite of our
best efforts, we were not able to evaluate many
babies who missed their one-year assessment
appointment date. Home visits helped to reduce the
dropout rate from 17% at one year to only 8% at two
year. Availability of good objective outcome
measurements is crucial for successful completion of
any good trial. Hence the objective
neurodevelopmental outcome measurement of MDI
and PDI using internationally accepted Bayley
Scales of Infant Development (BSID), which has
been standardized for the Indian population was
appropriately used at one and two years in this
study(10).
The intervention group of babies having a
statistically significant higher score for MDI and
PDI at one and two year of age, suggests that not only
early stimulation therapy is effective at one year but
also that effect is present even at two years, without
additional intervention in the second year. The
observation that, for increase of every 500 grams,
there is a significant and consistent increase in mean
values of the outcomes at 1 and 2 year and that in
every birthweight group, the mean values are higher
for the intervention group, again suggest that early
stimulation is effective across the birth weight
groups. Early intervention programs that go into
homes have a greater chance of reaching high-risk
infants, compared with those provided at a distant
centre. Better-educated mothers are more likely to be
convinced about the benefits of such inputs(14). In
the Indian context, there is a potential for introducing
home-based early stimulation program through the
Integrated Child Development Services. The data
provided shows conclusively that early intervention
is effective and hence the results of this study may
have policy implications.
ACKNOWLEDGEMENTS
Teena Jacoby, Annie John, Leena ML, Asokan N,
Child Development Centre, Medical College,
Thiruvananthapuram.
Contributors: MKC was involved in designing the study
and preparation of the manuscript and will act as
guarantor. EP was involved in quality assurance of data, LJ
did the analysis of data. BG, SM, KP were involved in the
data collection.
Funding: Kerala Health Research and Welfare Society,
Government of Kerala, Thiruvananthapuram.
Competing interests: None stated. The findings and
conclusions in this article are those of the authors and do
not necessarily represent the views of the funding agency.
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WHAT THIS S TUDY ADDS?
• CDC model early stimulation therapy done by the mother at home is effective in improving the developmental
status of neonatal nursery graduates at 1 year and the effect persists at 2 years without additional intervention.
INDIAN PEDIATRICS S26 VOLUME 46, SUPPLEMENT, JANUARY 2009
NAIR, et al. EARLY S TIMULATION OF A T-RISK BABIES
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