Pediatrics International (2016) 0, 1–10
doi: 10.1111/ped.13021
Original Article
Brazilian infant motor and cognitive development: Longitudinal
influence of risk factors
Keila RG Pereira, Nadia C Valentini and Raquel Saccani
School of Physical Education, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
Abstract
Background: Infant developmental delays have been associated with several risk factors, such as familial environmental, individual and demographic characteristics. The goal of this study was to longitudinally investigate the
effects of maternal knowledge and practices, home environment and biological factors on infant motor and cognitive outcomes.
Methods: This was a prospective cohort study with a sample of 49 infants from Southern Brazil. The infants were
assessed three times over 4 months using the Alberta Infant Motor Scale and the Bayley Scale of Infant Development (Mental Development Scale). Parents completed the Daily Activities Scale of Infants, the Affordances in The
Home Environment for Motor Development – Infant Scale, the Knowledge of Infant Development Inventory and a
demographic questionnaire. Generalized estimating equation with Bonferroni method as the follow-up test and
Spearman correlation and multivariate linear backward regression were used.
Results: Cognitive and motor scores were strongly associated longitudinally and increased over time. Associations
between the home affordances, parental practices and knowledge, and motor and cognitive development over time
were observed. This relationship explained more variability in motor and cognitive scores compared with biological
factors.
Conclusions: Variability in motor and cognitive development is better explained by environment and parental
knowledge and practice. The investigation of factors associated with infant development allows the identification of
infants at risk and the implementation of educational programs and parental training to minimize the effects of
developmental delay.
Key words cognition, delay, growth and development, infant, risk factor.
Developmental delays in infancy have been associated with
several risk factors of infant health (e.g. prematurity, low
birthweight, and infections),1–3 poverty,2,4 low parental education,4–6 lack of family structure7,8 and home opportunities for
development.2,9–12 In particular, infants with several siblings6,7
and who are exposed to environments low in stimuli13 with
poor parent interaction2 and few opportunities to engage in
learning activities2,14 often have developmental delays during
the first year of life.
The literature is also consistent in demonstrating the maternal risk factors (e.g. depression, societal violence, poor health
and nutrition) and protective factors (e.g. breast-feeding and
maternal education) for child development,15,16 as well as the
relationship between home affordances and child motor outcomes.2,10,12,17–20 Despite the well-established investigation of
home opportunities and infant development, few studies investigate the associations between home affordances and infant
Correspondence: Nadia C. Valentini, PhD, School of Physical
Education, Physical Therapy and Dance, Federal University of
Rio Grande do Sul, Porto Alegre, RS 90690-200, Brazil. Email:
[email protected]
Received 18 March 2015; revised 8 April 2016; accepted
13 April 2016.
© 2016 Japan Pediatric Society
cognitive development.12 In addition, little work has been
done to investigate the association between maternal knowledge and practice, and infant cognitive and motor delays. Consequently, within the home environment much less is known
about the vital resource of maternal knowledge and practice
and its association with development outcomes. Assessing
home environment as one construct and disregarding specific
affordances and care may limit the researcher’s interpretation
of risk and protective factors that mostly affect infant development. Furthermore, studies often focus on only one aspect of
maternal care at a specific time and its relationship to development: for example, the infant’s sleep position.21,22 Many
aspects, however, of the environment and maternal care interact and affect the infant differently through the first year of
life. Researchers have also suggested the need to examine the
long-time effect of environmental factors on infant motor and
cognitive development.2
Additionally, given that infants exposed to risk and low
opportunities to learn will often present delays,13,23–28 the present goal is to provide information to help health professionals
in the identification of risk factors and to prioritize the implementation of early child development programs and public
policies to benefit the infants from low-income families.
2 KRG Pereira et al.
In the present study, we carried out a longitudinal investigation of the effects of maternal knowledge and practices,
home environment, and biological factors on infant motor and
cognitive outcomes. We hypothesized that: (i) there would be
a positive association between motor and cognitive development over time; and (ii) different environment and biological
factors would be associated with increases in motor and cognitive development over time.
Methods
Participants
The longitudinal segment of the study began at the infants’
first assessment in an epidemiological study in South Brazil.
One hundred infants, from approximately 600 infants assessed
in public day-care centers, were enrolled in the longitudinal
study. A prospective cohort study was design to examine longitudinally how maternal knowledge and practices, the home
environment and biological factors relate to infant motor and
cognitive outcomes. Infants diagnosed with musculoskeletal
disorders (e.g. fractures, peripheral nerve injury, osteomuscular
infection) and mental disabilities were excluded from the present study and referred to further investigation and compensatory intervention. Initially, one assessment score was
obtained from the 100 infants enrolled. Thirty-two infants’
families did not attend the follow-up assessments. Three
assessment scores were obtained from 68 infants (2–
12 months of age). Nineteen families, however, discontinued
participation in the study due to day-care dropout and parental
unwillingness to complete the home environment and infant
biological factors questionnaires. Therefore, the study considered only of infants with three complete assessments of motor
and cognitive development and whose families completed the
questionnaires. Due to this criterion the sample consisted of
49 infants. Human subjects approval was obtained from the
University Research Ethics Committee, and consent was
obtained from the custodial caregiver(s) of each infant participating in the study.
Instruments
Infant development and biological factors
Alberta Infant Motor Scale (AIMS) was used to assess infant
motor skills. The AIMS is used to assess preterm and full-term
infants, from birth to 18 months of age, in four different subscales: prone (21 items), supine (nine items), sitting (12 items)
and standing (16 items). A trained evaluator usually completed
the assessment within 20 min of observation and with minimal
infant handling. Raw score is obtained by adding the four
subtotals (0–58 points), and is converted to a percentile to
compare infant development with the percentile ranks of agematched peers.29,30 The AIMS was previously validated for
Brazilian children with high internal consistency (a = 0.88)
and reliability (a = 0.90), and confirmed discriminative and
© 2016 Japan Pediatric Society
predictive power (P < 0.001) and temporal stability (q = 0.85;
P < 0.001).31,32
The Bayley Scales of Infant Development – second edition
(BSID-II) – Mental Scale33 was used to assess infant cognitive
development. The scale consists of a specific set of developmental play tasks assessing infant perceptual, discrimination
and response abilities, memory and verbal communication at
each month of corrected age. The total scale takes approximately 45 min to administer by a trained professional. The
sum of the successfully completed items produces the raw
score. Raw scores are converted to composite score and usually are used in reference to the norm to determine the Mental
Development Index.33
A questionnaire was sent home to be answered by the parents in regard to individual factors and to pre-, peri- and postnatal characteristics: age, sex, type of birth, gestational age,
Apgar score, birthweight and length, permanence (days) of
intensive care unit stay and mechanical ventilation. Family
income was also assessed.
Home environment and maternal practices
Two questionnaires were used to assess the home environment
and maternal practices: the Affordances in The Home Environment for Motor Development – Infant Scale (AHEMDIS)18 and the Daily Activities of Infant Scale (DAIS).34
The AHEMD-IS was used to assess socioenvironmental
risk factors and opportunities for motor development available at home for 3–18-month-old infants. AHEMD contains
questions organized in five dimensions: child characteristics,
family characteristics, physical space outside and inside the
home, daily activities, and play materials.18 Child and family
characteristics are assessed by numeric, contingency and categorical questions. We also inserted new questions concerning mother’s and father’s age, co-habitation, caregiver
employment status, family income and time of exclusive
breast-feeding (in months). Physical space is assessed with
dichotomous questions and is converted to a total score.
AHEMD daily activities assess caregiver practice and are
organized into two distinctive parts: part I consists of five
dichotomous (yes = 1 or no = 0) questions and a sum of
scores; and part II involves six Likert-type questions and a
sum of scores.
The DAIS was used to assess the placement practices,
specifically opportunities provided by the caregiver to promote
antigravity postural control and development in daily activities
during feeding, bathing, dressing, carrying, quiet and active
play, outings and sleeping. Each dimension is organized into
three groups of responses in an ordinal scale ranging from the
lowest (A) to the highest (C) developmental opportunity.34
The DAIS was originally designed to report infant position
every half hour, requiring infant position to be monitored for
the whole day. We adapted the DAIS and asked parents to
report daily, in the checklist, only the infant positions usually
involved in infant care (e.g. bathing and dressing). This adaptation was carried out because we noted parental difficulties in
Infant development and risk factors 3
responding to the DAIS in its original format. The dimension
sleeping position was organize into three categories: (A)
supine, (B) side and (C) prone position. Each dimension
received a score ranging from 1 (A) to 3 (C). DAIS total score
is obtained by summing the eight dimensions (0–24 points).
Maternal knowledge
For the investigation of parental knowledge of child development we used the Knowledge of Infant Development Inventory (KIDI).35 The KIDI provides information on parental
knowledge and practices, child development, and behavior.
The KIDI was designed to be easily accessible to people with
less formal education, and to be culturally neutral.35 It is
adapted for the Brazilian population.36 In the present study,
the 20 items regarding age at which infants develop certain
skills was used to assess maternal knowledge. Total score is
obtained by dividing the number of correct answers by the
total number of questions, and ranges from 0 (little knowledge) to 1 (much knowledge).35,36
Procedures
Infants were assessed three times over 4 months at the public
day-care centers they attended The assessment was conducted
in a quiet room by the leading researcher and two independent raters with >3 years extensive training in the use of
AIMS and BSID-II. Each assessment took approximately
40 min for each infant and was video-recorded. The recording
was used for inter-rater reliability. Three raters scored infant
performance using the recorded assessments, and there was a
high level of agreement among raters (intraclass correlation
coefficient >0.85). Friedman and Wilcoxon analysis also
showed no significant differences between raters’ scores
(P > 0.05). All parents and institutions were informed about
the results of the infant assessments. Information about public
services was provided to the families of infants identified with
low percentiles.
Questionnaires were sent to the parents or guardians. The
assessments related to parental knowledge and practice, and
infant and home characteristics were conducted at the three
assessment periods at the infants’ homes.
Statistical analysis
Statistical analysis was carried out with SPSS version 20.0.
Quantitative variables are reported using central tendency and
variability; qualitative variables are described using absolute
and relative frequencies. The longitudinal data were analyzed
using the generalized estimating equation (GEE) and Bonferroni procedure as the follow-up test.37–39 GEE was used in the
present study because it is a robust procedure for longitudinal
studies even with small samples. GEE also allows for multilevel analysis, and analysis of continuous outcomes even when
the variable is not normally distributed or lacks sphericity.
Furthermore, GEE uses within-subject scores and not the
assessment period mean, which is an advantage in longitudinal
studies. All the GEE assumptions were met in the present
study. Associations between quantitative variables were analyzed using Spearman correlation. Multivariate linear backward regression was used to analyze the independent variables
associated with motor and cognitive developmental scores and
to control confounding factors. Correlation was defined as
strong for r >0.60, mild for r 0.30–0.60; and poor for
r <0.30.40 Two tests of fit, which take into consideration the
collinearity of the variables in the models, were adopted:
Durbin–Watson test and graphic residual analysis. Good model
fit was defined as Durbin–Watson score <4; residual linearity;
and non-evidence of heteroskedasticity on residuals analysis.41,42 P ≤ 0.05 was defined as significant.
Results
Biological and demographic characteristics
The sample consisted of 49 infants: 12 preterm (24.5%) and
37 term (75.5%). The number of boys and girls were similar
(55.1% male) and the majority of the infants were delivered
by cesarean (53.1%). Participant biological factors are listed in
Table 1.
Family monthly income average was approximately three
times the minimum wage in Brazil (BRL2347.89 1733.36);
the minimum wage in Brazil is BRL788.00, corresponding to
approximately USD210.00 per month. The majority of the parents completed high school (mothers, 44.9%; fathers, 46.9%).
Table 1 Participant characteristics
Biological factors
Descriptive statistics
Mean SD
Gestational age (weeks)
Birthweight (g)
Birth height (cm)
Birth cephalic perimeter (cm)
APGAR (1 min)
APGAR (5 min)
ICU admission (days)
Mechanical ventilation
38.20
3156.33
48.01
32.18
8.25
8.95
3.59
1.12
2.57
456.20
2.67
1.90
1.65
1.22
9.80
4.02
Median (IQR)
39
3200
48
32
9
9
0
0
(37–40)
(2780–3580)
(46–50)
(30.25–34)
(7–9.75)
(8–10)
(0–0)
(0–0)
Min
Max
32
2200
41
29
5
6
0
0
42
3995
53
36
10
10
40
20
ICU, intensive care unit.
© 2016 Japan Pediatric Society
4 KRG Pereira et al.
Several parents completed <8 years of formal education;
16.3% of the mothers and 6.1% of the fathers studied as far as
elementary school, whereas 8.2% of the mothers and 10.2% of
fathers completed middle school. With regard to university,
26.5% of the mothers and 32.7% of the fathers completed
undergraduate degrees, and 4.1% of mothers and fathers had a
graduate degree.
Motor and cognitive development over time
Table 2 lists the motor and cognitive scores over time and the
results of the GEE statistical analysis as well as the comparisons using Bonferroni procedure as follow-up. Infant motor
and cognitive raw scores increased significantly over time
(P < 0.05). Similarly, motor scores in the postures (prone,
supine, sitting and standing) differed significantly with assessment period (P < 0.05). The acquisition of new motor and
cognitive skills was observed over time.
Strong and significant correlation at the three assessments
were observed between motor and cognitive total scores
(q > 0.8; P1 < 0.001). As motor performance increases, positive changes were observed in cognitive development,
demonstrating the intimate interrelationship between these
developmental processes. Figure 1 presents the distribution of
motor and cognitive scores over time.
Environmental and biological factors
Table 3 lists the descriptive statistics for the familial and environmental factors (maternal practices and knowledge, family
socioeconomic status and home opportunities for development)
over time, the GEE analysis and Bonferroni follow-up procedure. While some variables changed over time, others
remained stable. Maternal practices varied significantly over
time, A transition was observed from placing the infant in
more supported positions to positions with movement independence, and, consequently, with more developmental challenges. The number of toys at home significantly increases
over time, in parallel with increases in monthly family
income. As infant day-care attendance increases, also diversity
of experience, toys to manipulate and more independence in
movement were provided. Maternal knowledge, parents’ jobs
and co-habitation, and number of children and adults at home
remained stable over time.
Table 2 Motor and cognitive assessment scores over time
Age, scales and assessment period
Raw scores
Mean SD
Age (months)
A1
A2
A3
AIMS Prone Subscale
A1
A2
A3
AIMS Supine Subscale
A1
A2
A3
AIMS Sitting Subscale
A1
A2
A3
AIMS Standing Subscale
A1
A2
A3
AIMS total score
A1
A2
A3
BSID-II total score
A1
A2
A3
PGEE
Median (IQR)
Statistical tests
Range
Bonferroni
Min
Max
1–2
2–3
1–3
8.02 2.63
10.02 2.63
12.02 2.63
9 (6–10)
11 (8–12)
13 (10–14)
2
4
6
12
14
16
<0.001
<0.001
<0.001
<0.001
14.24 6.32
16.37 5.46
18.12 4.13
16 (7.5–21)
19 (12–21)
21 (16–21)
3
6
8
21
21
21
<0.001
<0.001
<0.001
<0.001
7.63 1.90
8.49 1.01
8.92 0.28
9 (6–9)
9 (8–9)
9 (9–9)
3
4
8
9
9
9
<0.001
<0.001
0.004
<0.001
8.94 3.37
10.24 2.47
11.24 1.76
11 (6–12)
12 (9–12)
12 (12–12)
2
4
4
12
12
12
<0.001
<0.001
<0.001
<0.001
6.94 3.37
8.96 3.62
11.08 4.02
6 (4.5–9)
8 (5–11.5)
11 (8–15)
2
4
5
16
16
16
<0.001
<0.001
<0.001
<0.001
37.76 13.99
44.10 11.49
49.43 9.33
41 (25.5–50)
48 (34.5–53.5)
53 (45.5–57)
11
19
27
57
58
58
<0.001
<0.001
<0.001
<0.001
69.22 15.11
78.43 13.08
86.59 12.81
74 (60.5–79.5)
81 (70.5–88)
88 (76–94)
27
37
59
95
103
111
<0.001
<0.001
<0.001
<0.001
A1, first assessment; A2, second assessment; A3, third assessment; AIMS, Alberta Infant Motor Scale; BSID-II, Bayley Scales of
Infant Development – 2nd edn; GEE, generalized estimating equation.
© 2016 Japan Pediatric Society
Infant development and risk factors 5
Table 4 lists multivariate linear backward regression results
for the motor and cognitive outcomes and the biological,
familial and environmental factors. In the three assessment
periods several environmental factors remained in the models,
which explain the variability in motor and cognitive development (adjusted R2 were large). Durbin Watson score <4 was
observed in the three assessment periods for motor
(A1 = 2.27; A2 = 2.20; A3 = 2.42) and cognitive (A1 = 2.19;
A2 = 1.85; A3 = 1.93) development. Residuals analysis
showed linearity and non-evidence of heteroskedasticity.
These results suggested a very good fit of the models without
collinearity between the independent variables. Several factors
remained as significant indicators in the models over time, such
as motor and cognitive developmental scores, family income,
paternal practices and education, and day-care attendance.
When considering motor development as the outcome,
cognition remained as a significant indicator in the models
in the three assessments. Higher cognitive scores were associated with better motor scores, stressing the correlation
results previously observed. Higher motor outcomes were
observed for infants from families with higher incomes in
two assessments periods (A1, A2). Higher motor performance was observed for the infants placed by theirs mothers
in more stimulating and independent positions in the first
assessment. Sex remained in the model but was non-significant.
When considering cognitive development as the outcome,
the set of variables that remained in the model increased. At
the three assessment periods higher cognitive scores were
observed for the infants with better motor performance. Sex,
parental education and maternal practices concerning infant
placement were associated with cognitive outcome in two
assessment periods (A1, A2). Higher cognitive scores were
observed for girls, and for infants from families with higher
formal education in which the infants were placed in more
stimulating positions, allowing free movements. In the third
assessment period (A3) more toys and diversity within physical space were associated with higher cognitive scores. Higher
cognitive scores were also directly associated with day-care
attendance and maternal practices, and, inversely related to
parental job. Although non-significant, these variables
remained in the model and helped to explain the variability in
the cognition scores.
Discussion
Fig. 1 Spearman correlation between motor and cognitive raw
scores at (a) assessment 1 (q = 0.918, P < 0.001), (b) assessment
2 (q = 0.901, P < 0.001) and (c) assessment 3 (q = 0.885,
P < 0.001). AIMS, Alberta Infant Motor Scale; BSID-II, Bayley
Scales of Infant Development – 2nd edn.
We examined that over time the maternal practices and knowledge, biological factors and home environment were significant
contributors to infant motor and cognitive development. The
main question addressed was: are the maternal practices and
knowledge, the home environment and biologic variables, risk
factors for infant motor and cognitive development over time?
In the present study, infants increased motor and cognitive
repertoire over time. Strong and direct correlations were
© 2016 Japan Pediatric Society
6 KRG Pereira et al.
Table 3 Familial and environmental factors over time
Score: mean SD or % (n)
PGEE
Statistical tests
Assessment periods
A1
Maternal practice
AHEMD-IS I
AHEMD-IS II
Breast-feeding (months)
DAIS score
Maternal knowledge
KIDI score
Socioeconomics status
Monthly family
income (BRL)
Home environment
Physical space
Home environment
Both parents employed
Parents together
No. toys, children and adults
Toys
Children
Adults
Day-care attendance
<3 months
3–6 months
7–12 months
A2
Bonferroni
A3
1–2
2–3
1–3
3.86 1.14
7.45 2.50
–
15.57 4.08
4.14 0.96
8.02 1.66
–
17.61 3.68
4.29 0.98
8.33 2.61
4.43 1.95
19.24 3.17
0.003
<0.001
ND
<0.001
0.003
0.111
ND
<0.001
0.840
0.222
ND
<0.001
0.013
<0.001
ND
<0.001
0.66 0.18
0.66 0.17
0.625 0.19
0.69
1.00
1.00
1.00
2267.55 1735.40
2374.08 1706.50
2402.04 1758.20
0.002
0.007
0.961
0.001
4.92 2.67
4.98 2.63
5.39 2.60
0.001
1.0
0.001
<0.001
89.80 (44)
63.30 (31)
at home
15.20 6.67
2.0 1.10
2.27 0.84
79.60 (39)
63.30 (31)
87.80 (43)
61.20 (30)
0.052
0.836
0.055
1.000
0.446
1.000
1.000
1.000
18.49 7.60
2.0 1.04
2.22 0.82
22.82 7.16
2.04 1.02
2.27 0.86
<0.001
0.605
0.739
<0.001
1.000
1.000
<0.001
0.937
1.000
<0.001
1.000
1.000
63.3 (31)
24.5 (12)
12.2 (6)
36.7 (18)
44.9 (22)
18.4 (9)
8.2 (4)
63.3 (31)
28.6 (14)
<0.001
<0.001
<0.001
<0.001
A1, first assessment; A2, second assessment; A3, third assessment; AHEMD-IS, Affordances in the Home Environment for Motor
Development – Infant Scale; DAIS, Daily Activities of Infant Scale; GEE, generalized estimating equation; KIDI, Knowledge of Infant
Development Inventory; ND, not done.
observed between motor performance and cognition in the
three assessment periods. Similar trends have been previously
reported for motor development trajectories of term43 and preterm infants.44,45 The increases in infant scores were expected
because a diversity of behavior acquisitions occurs in the first
2 years of life. The increase of quality in motor repertoire has
previously been reported in Brazilian infants from 1 to
6 months of age,46 similar to the present study, as expected.
Although stabilization in motor scores is sometimes
reported in the literature at specific ages, such as at the first
month32,46 and after 14 months,32 due probably to low sensitivity,32 in the present study infant motor scores increased
even after 14 months, specifically for the prone and standing
postures. Furthermore, in previous studies, cognitive scores of
infants from low-income families were reported to be stable
over time in Brazil,47 in contrast to the present results. The
difference in results is possibly due to differences in sample
characteristics: for example, Lordelo et al.47 reported cognitive development of infants from low-income families only,
whereas the present study also included middle class infants.
It is possible that the smaller change in cognitive scores was
more prevalent in infants from families with fewer resources
to support cognitive development.47
Furthermore, the present motor development model
accounted for the increases in variance in cognitive development: larger predictive scores were observed in A1, A2 and A3.
© 2016 Japan Pediatric Society
The cognitive developmental model also accounted for the
increases in variance in motor development as age increases:
almost equally stronger predictive values were observed in A1,
A2 and A3. The models indicated that motor development predicted cognitive development, and vice versa, demonstrating
the intrinsic relationship between these dimensions of human
development, because these variables stayed strong and significant within the model in the three assessment periods.
Moderate associations between motor and cognitive skills
have been previously reported.12,48 Furthermore, at 6, 9 and
12 months, gains in cognition are reported to align with gains
in motor development,49 similar to the present results for the
same age range. Specifically, the acquisition of the sitting
position and the ability to walk independently are considered
predictors of expressive vocabulary in infants.50 The inter-relationship between motor and cognitive development can be partially explained by the co-activation of certain brain regions in
cognitive and motor activities.51 The cerebellum is activated
by motor tasks and co-activated in cognitive tasks; also, this
circular relationship is also observed given that cognitive tasks
activate the pre-frontal cortex, the same region that is co-activated in a motor task.51 This powerful co-dependency highlights the importance of providing a motor- and cognitiveenriching environment for infants.
The biological factors were non-significantly associated
with motor and cognitive development in the present study.
Infant development and risk factors 7
Table 4 Multivariate indicators of motor and cognitive development
Assessment period
Motor development: Outcome
A1
Sex (M = 1; F = 2)
Mechanical ventilation
BSID-II score
DAIS score
Family income
A2
Sex (M = 1; F = 2)
BSID-II
Family income
A3
BSID-II score
Cognitive development: Outcome
A1
Sex (M = 1; F = 2)
AIMS score
Parental education
Day-care attendance
A2
Birthweight
Sex (M = 1; F = 2)
AIMS score
Maternal practice (AHEMD I)
DAIS score
Parental education
Day-care attendance
Both parents employed (yes = 1; no = 2)
A3
AIMS score
Toys
Physical Space AHEMD
DAIS score
B
EP
T
P
Adjusted R2
3.41
0.33
0.73
0.66
0.00
1.84
0.21
0.09
0.30
0.00
1.86
1.70
8.48
2.18
2.71
0.073
0.099
<0.001*
0.037*
0.011*
0.876
2.825
0.811
0.001
1.471
0.054
0.000
1.920
14.978
3.144
0.063
<0.001*
0.003*
0.860
0.618
0.058
10.601
<0.001*
0.751
4.78
0.91
3.16
2.70
1.77
0.07
0.98
1.42
2.69
12.81
3.21
1.91
0.011*
<0.001*
0.003*
0.065
0.876
0.00
4.97
0.82
1.467
0.85
3.83
2.23
4.22
0.00
1.39
0.08
0.811
0.28
0.79
1.17
2.15
2.03
3.59
9.78
1.808
3.05
4.85
1.91
1.96
0.052
0.001*
<0.001*
0.081
0.005*
<0.001*
0.07
0.06
0.916
0.84
0.36
0.96
0.89
0.84
0.17
0.34
0.44
6.56
2.13
2.77
2.02
<0.001*
0.040*
0.009*
0.05
0.844
*P < 0.05. AHEMD, Affordances in the Home Environment for Motor Development; AIMS, Alberta Infant Motor Scale; BSID-II,
Bayley Scales of Infant Development – 2nd edn; DAIS, Daily Activities of Infant Scale.
For example, in contrast to several studies,19,44,45 gestational
age and birthweight were not significantly associated with
motor scores and only partially explained cognitive variance
in scores restricted to the second assessment. It is important to
note that previous studies investigated only gestational age
and birthweight related to development, therefore they were
more likely to show this relationship.19,44,45 In contrast, two
studies on biological and environmental risk factors provided
results more similar to the present study.2,6 Specifically, in
Brazil and Greece, social and environmental factors contributed more to infant development than did biological
factors.2,6
The only significant finding relative to individual characteristics was sex. At young age sex remained in the regression
model and partially explained motor development variance,
but at the third assessment girls and boys had similar motor
performance. Differences in sex in infant motor development
is not a common finding; on the contrary, similar levels of
motor development have been constantly reported in the literature regarding infants.2,19 In regard to cognitive development,
however, girls had higher scores compared with boys, and sex
was also a significant predictor in the first two assessment
periods (A1, A2). Although the present study reports higher
scores before 1 year of age, similar advantages in cognitive
results for girls were previously reported specifically for the
mental development at 12 months,19 expressive vocabulary at
17 and 19 months52 and receptive and expressive communication at 18 months.6 Further studies are necessary to determine
whether parents are providing dissimilar opportunities for
development for boys and girls at a young age. The present
results strongly suggest that the investigation of risk factors
related to infant development may require a more all-inclusive
design approach in order to examine the potential risks and
predictors for development. Consequently, biological characteristics should be considered not only specifically in the
infants but also in their environment.
Of the significant factors related to infant development,
interestingly the family and environment factors explain a large
variance of motor and cognitive development over time,
remaining in the regression models in the three assessment
periods. The variety of toys in the home environment merits
special note: this factor had a significant positive relationship
© 2016 Japan Pediatric Society
8 KRG Pereira et al.
with cognitive scores in the third evaluation. The literature is
consistent in showing the positive associations between accessibility to toys and motor development in different cultures and
countries, even though the strength of the relationship is somewhat different.2,12,18,20 When related to cognition, however,
there are fewer studies on the importance of toys. Toys are
considered predictors of development18 and, when available to
the infant, it is likely that they will promote motor development12,20 through affordance of new and diverse motor actions
that will probably stimulate cognitive acquisitions. This finding
may be particularly important to low-income families, who are
usually restricted in the purchase of toys that could promote
development. In the present study, similar to the current literature, results related only to the presence of toys at home. It
was not questioned if the child usually played with it. In Brazil, the rooms in infant day-care centers are often organized so
that toys stay out of reach of non-walking infants, restricting
the possibilities of manipulation. Further information on the
quality of infant toy exploration is necessary in order to more
deeply understand its influence on cognitive development, as
observed in the present study. Furthermore, it is important to
highlight that parents can make toys, and infants from lowincome families at home may use safe objects as toys.
Another significant factor related to cognitive development
during the first year of life (specifically at the third assessment) was the physical space. Prior studies have suggested
that appropriate physical environment is strategically related
to child cognitive acquisition.53,54 Previous studies in Brazil
suggested physical space as a predictor of child motor development, and space restriction as a risk factor.2 The home’s
physical environment influences the opportunities for stimulation, restricting and/or encouraging infant exploratory behavior.13 It is worth noting that this relationship was found when
infants were on average 12 months old, the initiation period of
independent walking. Walking requires accessible physical
space and furniture for support; if those conditions are met,
infants will explore their environment and seek human interaction, creating affordances on their own that may positively
affect cognitive acquisition.
One of the most remarkable results was in respect to maternal practices. Significant relationships were found between the
mother’s placement of the infant in different positions and
motor scores at first evaluation, although cognitive scores at
the second and third assessment were also associated with this
practice. The current literature is consistent in addressing the
importance of this practice. Most studies, however, focused
only on the infant sleeping position and still had conflicting
results. The negative influence of the supine position on infant
motor development during sleep has been previously
reported,46,55–57 whereas no differences were found in several
studies.21,58 The data on the positions that infants use to
explore environments while awake are scarce; an important
contribution of the present study to current knowledge. In the
present study a relationship was noted between infant placement when awake and motor development at the first assessment, which may be a consequence of infant upper body
© 2016 Japan Pediatric Society
control at this time. In the second and third assessments, however, associations were observed with cognitive development.
Change in infant position while awake probably allows infants
to use visual, sensory and motor abilities to explore the surroundings, leading to cognitive development. The present
results drew the parents’ attention to the importance of diversity in infant placement for promoting the acquisition of motor
and cognitive skills, especially in positions that require muscle
strength and postural control against gravity,44,46 such as sitting, being prone, and standing. In addition, differences are
reported in the literature concerning the development trajectories of children from different countries,59,60 probably due to
cultural differences in parental daily practices of holding and
placing infants.
Considering family characteristics, family income and parental education are worthy of mention. Family income was a
constraint to infant motor development at the first and second
assessments. Previous studies have consistently reported the
dangerous association of family low income with motor
delays for Brazilian children.2,13,19,25,61 Regarding education,
higher education is frequently associated with more appropriate infant care and consequently development. Maternal formal education has been reported as a protective factor for
infant development2,6,17,19,56; and, although less reported in
the literature, paternal education is also positively related to
higher development scores for infants.6,13,56 In the present
study, parental formal education was inversely related to
infant cognitive development at the first and second assessments. One plausible explanation is that higher maternal educational implies higher workload, which would restrict
parental opportunities for interaction and infant development.52 Given that parental interactions with infants are essential to promote development2,13 and we found an inverse
association between parent education and infant development,
the next reasonable research step is to examine the different
levels of parental education, controlling for workload and time
spent interacting with their infants.
Another interesting finding was that cognitive development
was enhanced by the duration and frequency of infant attendance at day care. Contradictory results are observed for infant
development in relation to day-care attendance: some studies
report a positive impact on motor development,13,18 whereas
shortcomings have been reported, suggesting that day care
centers are restricted in provided movement opportunities for
1-year-old infants.2 In the present study, the positive association with cognitive development drew our attention to the adequate opportunities for cognitive acquisition that may be
offered for infants in the daily day-care center routine, using
colorful toys, play time and singing activities; activities with
great potential to affect cognition.
Implications
Over time different factors influenced the development of the
studied infants, with a prevalence of environmental factors
over individual factors. Therefore, the home environment has
Infant development and risk factors 9
a great potential to influence infant development, and should
be the target of diagnosis and intervention studies as well as
of parental education programs. In order to reduce persistent
inequalities in infant development, interventions are urgently
needed to reduce infant risk.
Mapping the family environment and maternal practices
and knowledge could identify potential risk factors for developmental delays. Early identification of these risk factors can
help the family to provide greater opportunities for the infants
to fully develop. Precautionary strategies such as: (i) incorporating assessment of motor and cognitive development in the
public health units; (ii) promoting workshops to educate parents on how to organize an appropriate home environment and
how to take care of their infants and stimulate them; (iii) distribution of information booklets and DVDs of these guidelines on infant care at hospitals, day-care and educational
centers; (iv) and training of health professionals in the identification of risk factors and methodological procedures to
improve infant quality of life.
Finally, future research should focus on specific age
groups, and determine which environmental factors are more
likely to strongly influence specific periods of development.
Also, it is important to assess home affordances, to determine
whether toys and physical space are available at home and if
infants are exposed frequently to a variety of perceptual–motor
experiences in the home environment.
Acknowledgment
The authors would like to thank CAPES – Coordenacß~ao de
Aperfeicßoamento de Pessoal Docente, for financial support for
this study.
Disclosure
The authors declare no conflicts of interest.
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