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Comparison of the effects of
perceptual-motor exercises, vitamin D
supplementation and the combination of
these interventions on decreasing
stereotypical behavior in children with
autism disorder
Hadi Moradi
1
, Mehdi Sohrabi
1
, Hamidreza Taheri
1
,
Ezzat Khodashenas
2
, and Ahmadreza Movahedi
3
1
Department of Motor Behavior, Faculty of Sport Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
2
Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
3
College of Sport Sciences, University of Isfahan, Isfahan, Iran
Objectives: The aim of this study was to examine the combined effects of perceptual-motor exercises and
vitamin D
3
supplementation on the reduction of stereotypical behavior in children with autism disorder (ASD).
Methods: In this study, 100 eligible children with age ranging from 6 to 9 years were randomly selected and
divided into four groups: Group A—perceptual-motor exercises (n¼25); Group B—25-hydroxycholecalciferol
(25 (OH) D) (n¼25); Group C—perceptual-motor exercises and 25 (OH) D (n¼25); and Group D—con-
trol (n¼25).
Results: The stereotypes decreased from elementary level, 17% in Group A, 13% in Group B and 28% in
Group C among the participants. There was no change in the stereotypical in the control group during the
interventions. Also, the stereotypes in Group C showed the highest decrease, compared to the other
three groups.
Conclusions: We concluded that combination of perceptual-motor exercises and vitamin D
3
supplementation
in children with ASD leads to significant reduction in their stereotypic behaviors.
Keywords: Stereotypical, perceptual-motor exercises, vitamin D
3
, autism spectrum disorder
Introduction
Stereotypical behaviors are one of the main symptoms
in individuals with autism disorder (American
Psychiatric Association 2013). Patients with autism
show a variety of stereotypical behaviors. It seems that
stereotypical movements aim to provide sensory input
and hence are considered self-stimulating (Schmitz
et al.2017). The stereotypical movements are known as
very constant, repetitive, non-flexible, abnormal,
strange, and uncanny behaviors, performed mainly
without a specific purpose (Berkson and Davenport
1962, Rapp et al.2004).
The stereotypical behavior in individuals with autism
disorder causes significant disruptions in learning
process (Schmitz et al.2017), self-disturbing behaviors
(Bodfish et al. 2000), behavioral problems (Gabriels
et al. 2005), and delayed response to environmental
stimuli (Lovaas et al.1971). The movements often take
almost the entire attention of the child, so that he/she is
unable to follow and respond to other stimuli, and they
are highly resistant to treatment (Bodfish et al.2000).
Therefore, stereotypical behaviors are a major problem
for parents and doctors associated with these children,
so paying attention to these behaviors and implement-
ing appropriate methods to decrease these behaviors is
of great importance.
Despite the deficits and its effects on individuals
with autism, research has shown that the use of appro-
priate interventions can have a positive effect on these
deficits. Various treatment methods have been reported
Correspondence to: Mehdi Sohrabi, Department of Motor Behavior,
Faculty of Sport Sciences, Ferdowsi University of Mashhad, Mashhad,
Iran. Email: sohrabi@um.ac.ir
#The British Society of Developmental Disabilities 2018
DOI 10.1080/20473869.2018.1502068 International Journal of Developmental Disabilities 2018 VOL.0 NO.0 1
by researchers to improve deficits in individuals with
autism disorder, such as physical activities (Bahrami
et al. 2016), nutrition (Amminger et al.2007), social
stories (Gray and Garand 1993), games, and verbal
behavior training (Yoder 2006). Studies on physical
activities have confirmed the effect of these interven-
tions on improving the children’s academic skills, per-
ceptual function, social skills, self-harm behaviors, and
aggression (Allison et al.1991, Movahedi et al.2013,
Hilton et al.2014, Pan et al.2016). Research indicates
that the motor skills of young children with autism
spectrum disorder (ASD) are significantly delayed and
of poor quality (Green et al.2009). Low levels of phys-
ical activity can lead to an unhealthy body composition
and increased morbidity (Janssen and LeBlanc 2010),
thus potentially placing individuals with ASD at greater
risk for negative health outcomes. It is possible that low
levels of motor-skill proficiency may be one of the con-
tributing factors, in conjunction with social factors, to
the physical inactivity in children with ASD (Bremer
and Lloyd 2016). Therefore, the improvement of motor
skills may be crucial for children with ASD because it
enables them to share physical activity with their peers
and allows them to benefit from the benefits of physical
activity (Bremer and Lloyd 2016). Children with autism
have deficiencies in perceptual-motor processes (Jepsen
and VonThaden 2002). So it is very important for chil-
dren to have a rich and strong background of perceptual
motor experiences as a base of the motor and nervous
systems (Piek et al. 2006). The efficiency of exercise-
based interventions on stereotypic behaviors in individu-
als with autism has rarely been studied. Investigators
have not yet empirically studied the role played by per-
ceptual-motor exercises on reduction of stereotypic
behaviors in children with autism spectrum disorders, in
the present study our main goal was to determine
whether perceptual-motor exercises to children with aut-
ism disorder lead to reductions in their stereo-
typic behaviors.
Another factor that may play a role in children’s
development in the first years of life is the nutritional
effects at early ages. Neural structures are sensitive to
environmental and nutritional factors like vitamin D,
which play an important role during this period (Harms
et al. 2011). Vitamin D has been found to have a poten-
tial role in brain homeostasis and development, such as
neuronal differentiation, neurotransmission, and synap-
tic function (Cannell 2017, Wang et al.2016). Vitamin
D deficiency is reported to be widespread worldwide
(Palacios and Gonzalez 2014). Low levels of vitamin D
induce negative changes on anxiety and social behavior
(Pan et al.2014), immune system (Hewison 2010), and
degradation of cognitive function (Grung et al.2017).
Vitamin D deficiency is also involved in the incidence
of autism disorder (Wang et al.2016). Majority of stud-
ies have conclude that vitamin D level in children with
ASD is significantly lower than that in healthy individ-
uals (Du et al.2015, Fernell et al.2015, Saad et al.
2018). We can deduce that low vitamin D level is com-
mon and an ongoing condition in children with ASD,
even evolving toward the adult period (Jia et al.2018).
The brain of individuals with autism spectrum dis-
order has significantly lower concentrations of serotonin
compared to those without autism (Chugani et al.
1999). The disruption of the serotonergic system is one
of the most consistent observations associated with aut-
ism (Zafeiriou et al. 2009). Investigators have shown
that serotonin plays a major role in autism (Kane et al.
2012, Yang et al. 2012, Boccuto et al.2013b, Patrick
and Ames 2014). Researchers have shown that the dis-
turbances of brain key neurotransmitters including sero-
tonin play a role in the maintenance of stereotypic
behaviors (Schoenecker and Heller 2001). However,
further reduction of brain serotonin in individuals with
autism is exacerbated by the acute reduction of trypto-
phan and symptoms such as repetitive behaviors and
face recognition patterns, which revealed the
continued need for serotonin to modulate these behav-
iors (Daly et al.2012). Though vitamin D supplementa-
tion might improve symptoms in children with autism
spectrum disorder, yet, study in this area is limited
(Saad et al. 2016a, 2016b). Therefore, previous studies
suggest more studies to be carried out (Patrick and
Ames 2014).
Despite evidence that shows delay in motor skills
and inadequate levels of vitamin D as the main indica-
tors for diagnosis of autism spectrum disorder, few
researches have evaluated their impact as interventions
on the deficits of children with autism disorder. To our
knowledge, studies on stereotypical behaviors have
been conducted more in case studies or small research
projects (Jia et al.2015). In addition, no study has
examined various combinations of interventions on chil-
dren with autism. Therefore, this study is one of the
first studies to examine the combination of vitamin D
3
and perceptual-motor activities on reducing the stereo-
typical behavior of children with autism disorder. Given
that children with autism suffer from a wide range of
disorders, the cause of which has remained unknown to
date, the researchers suggest using a combination of
interventions to address the deficiencies in individuals
with this disorder. Hence, the present study sought to
examine two important interventions and combine these
two interventions on children with autism. Finally, the
main aim of this study was to compare the efficacy of
perceptual-motor exercises and vitamin D
3
supplemen-
tation and the combination of these two interventions
on reducing stereotypical behavior in children with aut-
ism disorder. The results of this study provided benefi-
cial empirical evidence for perceptual-motor exercises
and vitamin D
3
supplementation and combining these
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
2International Journal of Developmental Disabilities 2018 VOL.0 NO.0
two interventions to improve stereotypical behavior in
individuals with autism disorder.
Methods
Participants
Participants were students ranging in age from 6 to 9
years (M ¼7.62 years, SD =1.15) from one of three
specialized institutions for youth with ASD who were
selected randomly to participate in the present study
(see Table 1 for additional demographic information
and baseline ASD-specific symptom severity). The chil-
dren were living with their own families, and attended
one of three institutions for students with autism. Each
participant had been formerly diagnosed as having ASD
using the Diagnostic and Statistical Manual of Mental
Disorders-Fifth Edition, Text Revision (DSM-5)
(American Psychiatric Association 2013). Participants
were screened by an experienced physician and were
found eligible to participate in the study. Participants
were 100 children with ASD whom were selected from
a sample of 250 children with autism. All participants
were in a good nutritional state. In total, 139 children
with ASD were excluded as they did not meet the inclu-
sion criteria. A total of 11 participants were also
excluded as their families declined to participate in
the study.
The inclusion criteria for this study are an autism
diagnosis confirmed by a psychologist along with a
medical team and based on diagnostic criteria DSM-
5, obtaining consent from parents, vitamin D serum
level less than 30 ng/ml, chronological age between
six and nine years, IQ more than 70, sound sense
of sight and hearing, lack of orthopedic and respira-
tory disorders, and lack of seizure attacks in the
last two years. Participants who had associated
gastrointestinal problems, children with feeding prob-
lems or malnutrition, genetic disorders, autoimmune
disorders, anemia, neurological diseases, and meta-
bolic disorders, children with known endocrine, car-
diovascular, pulmonary, and liver or kidney disease,
history of severe head trauma or stroke, as well as
any subjects receiving vitamin D-containing prepara-
tions and drugs that may affect vitamin D levels
were excluded.
None of the participants had officially received phys-
ical activity and vitamin D interventions in the last six
months. In addition, they were all following identical
treatment strategies at the autism center. All subjects
had a good nutritional status; children with feeding
problems or malnutrition were excluded from the study.
Then the participants were randomly assigned into four
groups: Group A–perceptual-motor exercises (n¼25);
Group B–vitamin D
3
supplementation (n¼25); Group
C–perceptual-motor exercises and vitamin D
3
supple-
mentation (n¼25); and Group D–p
\\lacebo (n¼25). Table 1 provides the characteris-
tics of the participants, including their chronological
age, gender, IQ, and the level of Vitamin D before the
interventions. This study has been carried out in
accordance with the code of Ethics of the World
Medical Association (Declaration of Helsinki) for
experiments involving humans. All procedures are
approved by the Ethical Committee of Ferdowsi
University of Mashhad, Iran. Informed consent had
been obtained from parents of all participants prior to
their inclusion.
Experimental interventions
I. Group A: Perceptual-motor exercises
The motor activities for this study were taken from
Perceptual–motor activities for children by Johnstone
and Ramon (2011). In designing this protocol, attempts
were made to use previous studies carried out in this
field (Kurtz 2007). The activities, content, and goals of
the intervention are listed in Table 2.
II. Group B: Vitamin D
3
supplementation
Group A consisted of 25 patients who were ran-
domly allocated to receive vitamin D
3
drops, 300 IU/kg/
day not to exceed 5000 IU/day (Saad et al. 2016a,
2016b) for 3 months.
Table 1. Participants’characteristics (age, sex, autism severity, IQ, and 25 (OH) D levels) at the pre-intervention time.
Group A M±SD Group B M±SD Group C M±SD Group D M±SD p Value
ASD 25 25 25 25
Age (years) 1.03 ± 7.64 0.97 ± 8.04 1.22 ± 7.60 1.25 ± 7.20 0.08
Sex (male/female) male male male male
Autism severity 12.94 ± 53.20 14.96 ± 56.64 19.54 ± 55.68 19.58 ± 58.16 0.77
IQ 7.38 ± 91.92 6.96 ± 91.52 8.06 ± 92.84 6.45 ± 93.40 0.79
25 (OH) D levels (ng/ml) 5.02 ± 11.88 4.61 ± 12.60 4.79 ± 13.04 4.87 ± 11.52 0.67
Abbreviations: Group A: perceptual-motor exercises; Group B: vitamin D
3
supplementation; Group C: perceptual-motor exercises and
vitamin D
3
supplementation; Group D: Placebo; M: mean; SD: standard deviation
Autism severity: Sum of the GARS-2 (Gilliam Autism Rating Scale-Second Edition) three subscales (stereotypy, communication and
social interaction) raw scores
ANOVA test were used to check if there are differences between the 4 groups. Significant differences between the 4 groups were illus-
trated as p<0.05.
Significant: p<0.05
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
International Journal of Developmental Disabilities 2018 VOL.0 NO.0 3
III. Group C: Perceptual-motor exercises and Vitamin
D
3
supplementation
This involved performing a combination of
Perceptual-motor Exercises and taking Vitamin D
3
for
3 months (Table 3).
IV. Group D: Placebo
Group D consisted of 25 patients who received a
matching placebo drops with the same taste and color
of vitamin D
3
drops for 3 months. The placebo con-
sisted of a combination of polysorbate 20, which is the
same fragrance ingredient used in vitamin D drops in
addition to glycerin, disodium edetate, and b-cyclodex-
trin in purified water.
Materials
a. Gilliam Autism Diagnostic Inventory-Second Edition
(GARS-2)
We used the stereotypy behavior subscale of Gilliam
Autism Rating Scale-2 (GARS-2) to evaluate changes
in participants’stereotypy behavior intensity (Gilliam
2006). Gilliam Autism Rating Scale-Second Edition has
been widely used in research studies and educational
program (Worley and Matson 2011). The stereotypy
subscale of GARS-2 contains 14 items that describe
specific, measurable, and observable stereotyped behav-
iors. It incorporates observations, parent or teachers
interviews, and questions completed by the examiner
according to their interpretation. The items of the sub-
scale ask caregivers how often a child: 1. Avoids estab-
lishing eye contact, looks away when eye contact is
made; 2. Stares at hands, objects, or items in the envir-
onment for at least 5 seconds; 3. Rapidly flicks fingers
or hands in front of eyes for periods of 5 seconds or
more; 4. Eats specific foods and refuses to eat what
most people will usually eat; 5. Licks, tastes or attempts
to eat inedible objects; 6. Smells or sniffs objects; 7.
Whirls, turns in circles; 8. Spins objects not designed
for spinning; 9. Rocks back and forth while seated or
standing; 10. Makes rapid lunging, darting movement
when moving from place to place; 11. Walks on tiptoes;
12. Flaps hand or fingers in front of face or at sides;
13. Makes high-pitched sounds; and 14. Slaps, hits, or
bites self or attempts to injure self in other ways.
Parents and teachers are asked to rate the individual
based on the frequency of occurrence of each stereo-
typed behavior under ordinary circumstances in a 6-h
period. The current study concentrated on the total raw
score in the stereotypy subscale of GARS-2. The
Table 2. Perceptual-motor exercises protocol.
Physical
exercises Length (min) Contains Target
Warm up 10 Jogging, stretching Warm up and stretching
Perceptual-motor
exercises
45 1. Jumping: Such as jumping back and forth on
the squares (30 x 30 cm), jumping succession,
crosswise jumping (a jump to the right and a
jump to the left), etc.
2. Hopping: Such as hopping back and forth,
opping in succession, crosswise hopping (a hop
to the right and a hop to the left), etc.
3. Static and dynamic balance: Such as standing
with the dominant foot on a hard surface,
walking on a balance beam with eyes opened,
etc.
4. Hitting ball with feet: Such as walking alongside
blue and red balls and hitting the red ones, etc.
5. Throwing ball to the target by hand: Such as
throwing a ball into the basket from a distance
of one meter or 1.5 meters, etc.
6. Throw and receive ball: Such as throwing a
plastic ball to a wall at a distance of one meter
and catching it by hand, etc.
Improvement of: Stability skills, Locomotor
skills, Manipulative skills, dynamic bal-
ance, static balance, motor planning,
motor coordination, eye–hand coordin-
ation, eye–foot coordination, gross
motor coordination, body awareness,
tracking skills, transference, arm-leg
strength, body awareness, directionality,
throwing accuracy, precision, spatial
awareness, Kinesthetic awareness,
tactile awareness, Unilateral movement
Cool down 5 Walking slowly, stretching Cool down and recovery
Table 3. Vitamin D levels in ASD patients before and after vitamin D
3
supplementation.
Group
Before vitamin D therapy
(M ± SD)
After vitamin D therapy
(M ± SD)
pValue
(paired samples test)
A 5.02 ± 11.88 4.56 ± 12.04 0.61
Vitamin D levels (ng/ml) B 4.61 ± 12.60 6.48 ± 24.36 0.01
C 4.79± 13.04 5.76 ± 24.04 0.01
D 4.87 ± 11.52 3.95 ± 11.08 0.28
Group A: perceptual-motor Exercises; Group B: vitamin D
3
supplementation; Group C: perceptual-motor exercises and vitamin D
3
sup-
plementation; Group D: Placebo.
M: mean; SD: standard deviation
: Significant at p<0.05.
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
4International Journal of Developmental Disabilities 2018 VOL.0 NO.0
subscale is both reliable and valid and has high psycho-
metric properties (Worley and Matson 2011).
B. Evaluation of the level of Vitamin D by the
Elecsys method
Serum 25(OH) D is considered to be adequate if it is
30 ng/mL, inadequate if it is between <30 and
>10 ng/mL, and deficient if it is 10 ng/Ml (Mostafa
and Al-Ayadhi 2012). After sampling the blood from
the participants, the Elecsys 2010 device made in the
German Roche Company was used to evaluate the lev-
els of Vitamin D. Investigators have found a debate
about values of the normal levels of vitamin D; if the
value should be equal to, or more than, 20 ng/ml, 30 ng/
ml, or higher even still (Holick et al.2011, Stubbs
et al.2016). Based on this technology and combined
with well designed, specific and sensitive immunoas-
says, Elecsys delivers reliable results (Connell et al.
2011). Children whose Vitamin D serum levels were
less than 30 ng/ml had the inclusion conditions to enter
the study. Serum Vitamin D levels were measured
before and 3 months after treatment (Table 4).
C. Raven IQ test
This test is comprised of abstract images which cre-
ate a logical sequence and is administered separately
(Raven et al.1996). This test has a high level of valid-
ity (0.80) and can be administered to groups (Raven
et al. 2008). This tool in the study was used to screen
and homogenize the general intelligence level of chil-
dren with autism.
Procedure
Each child who qualified to participate in this study had
been previously diagnosed with ASD by a clinician or
school psychologist according to the Diagnostic and
Statistical Manual of Mental Disorders (American
Psychiatric Association, 2013). At the initial assess-
ment, all parents completed a supplemental information
form in order to provide demographic data and a brief
developmental history of their child.
We administered stereotypical behavior subscale of
GARS-2 before intervention (pre-intervention) and
post-intervention (3 months) via interview with the
participants’parents, care givers and teachers and by
child direct observation. We organized a separate for-
mal meeting where we asked the participants’parents,
caregivers, and teachers to read over the statements
grouped with each number in the subscale. Then we
asked them to compromise and agree on the statement
within each group that best describes the way they have
been feeling about the child during the previous week.
In Group Perceptual-motor Exercises (Group A), to
ensure quality in program implementation, the physical
activity intervention was implemented as prescribed and
supervised by the primary researcher for each session.
The researcher received help from an instructor at the
Center of Autism. This instructor had 10 years of
experience with autistic children. If the instructor did
not implement the instructional sequence of each com-
ponent of the intervention as intended, the primary
researcher intervened to assist the instructor. If any par-
ticipant engaged in off-task behavior during the pro-
gram, the instructor managed the behavior, and the
primary researcher assisted the instructor when
required. The sessions were carried out in a therapy
room located at the Center of Autism. The course lasted
for 3 months and the sessions were thrice a week. Each
session was 60 minutes long. They included stretching
and jogging (10 minutes), main perceptual-motor
Exercises (45 minutes), and cool down (5 minutes)
(Table 2).
Children with ASD in Group Vitamin D
3
supple-
mentation (Group B), under the control of the
researcher, consumed Vitamin D
3
tablets (300 IU/kg/
day not to exceed 5000 IU/day (Saad et al. 2016a,
2016b) for 3 months). In Group C, both interventions
of Groups A and B were conducted for 3 months (The
protocol of Perceptual-motor Exercises was 36 sessions
(3 months) at 12 weeks and three sessions per week,
with each session lasting 60 minutes þreceive vitamin
D
3
drops, 300 IU/kg/day not to exceed 5000 IU/day for
3 months). Children with ASD in Group D also
received a matching placebo drops with the same taste
and color of vitamin D
3
drops for 3 months. The rate of
changes in the severity of stereotypical behavior was
evaluated using the stereotypical subscale of GARS-2
before and after the intervention (Table 3).
Table 4. Vitamin D levels in ASD patients before and after vitamin D
3
supplementation.
Group Pre-intervention Intervention Post-intervention (3 months)
A Stereotypy was assessed Participants were instructed Perceptual-motor
Exercises for 36 sessions
Stereotypy was assessed
B Stereotypy was assessed Vitamin D
3
supplementation (300 IU/kg/ day not to
exceed 5,000 IU/day)
Stereotypy was assessed
C Stereotypy was assessed Participants were instructed Perceptual-motor
Exercises for 36 sessions þVitamin D
3
supplemen-
tation (300 IU/kg/ day not to exceed 5,000 IU/day)
Stereotypy was assessed
D Stereotypy was assessed received placebos (matching placebo drops with
the same taste and color of vitamin D
3
)
Stereotypy was assessed
Abbreviations: Group A: perceptual-motor exercises; Group B: Vitamin D
3
supplementation; Group C: perceptual-motor exercises and
Vitamin D
3
supplementation; Group D: control
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
International Journal of Developmental Disabilities 2018 VOL.0 NO.0 5
Statistics
We used a Kolmogorov–Smirnov test to assess the nor-
mality of distribution of the data. To study the changes
in stereotypy severity before and after the intervention,
paired t-test was used. Then, an analysis of covariance
(ANCOVA) test and a Bonferroni follow-up test were
used to determine the differences between the four
groups. For all statistical analyses, p0.05 was consid-
ered to indicate statistical significance. The data were
also presented as mean (±) and standard deviation (SD).
Results
Table 5 presents descriptive information about the
groups at the pretest and post-test stages.
First, t-test was used to determine whether the
groups have been affected by interventions over the
course of time. The results showed significant differen-
ces in the severity of stereotypy severity in the experi-
mental groups during interventions (p¼0.01) and
stereotypy severity significantly improved after the
intervention. However, in the control group, the differ-
ence was not statistically significant (p¼0.51)
(Table 5).
Table 6 provides the results of the ANCOVA test,
indicating a significant difference between the groups.
To carefully investigate the difference between the
four groups in the variable stereotypy severity, the
Bonferroni test was used. Here the estimations were as
follows: The severity of stereotypy severity in the three
experimental groups (group-A, B, and C) had a signifi-
cant difference compared with the control group
(p¼0.01). No significant difference was observed
between perceptual-motor exercises groups and the
group with vitamin D
3
supplements in the severity of
stereotypy severity (p¼1.00). The severity of stereo-
typy severity in the perceptual-motor exercises group
and the group with vitamin D
3
supplements was signifi-
cantly different from the other three groups (p¼0.01).
This represents a significant improvement in stereotypy
severity in the combination group, compared to the
other three groups (Table 6).
Discussion
The aim of this study was to compare the effects of per-
ceptual-motor exercises and vitamin D
3
supplementa-
tion and the combination of these interventions on the
improvement of stereotypical behaviors in children with
autism disorder. The findings showed a significant
reduction in the stereotypical behavior of ASD children
in the three experimental groups after the end of the
interventions. The stereotypical behavior reduced from
the elementary level 17% in the group of perceptual-
motor exercises, 13% in the group of vitamin D
3
sup-
plementation and 28% in the combined group of per-
ceptual-motor exercises and vitamin D supplementation
among participants. There was no significant change in
the reduction of stereotypical behavior in children with
autism disorder in the control group. The results also
showed that stereotypical behaviors in the combined
group (perceptual-motor exercises and vitamin D
3
sup-
plementation) significantly improved compared to the
other three groups.
The usefulness of physical interventions for improv-
ing the symptoms of children with autism disorder has
been confirmed in several studies (Brand et al. 2015,
Bremer and Lloyd 2016, Ketcheson et al. 2017).
Regarding the use of physical activities in improving
the stereotypical behavior, studies on these
Table 5. Results of the stereotypy subscale of GARS-2 in response to intervention.
Group PRI (baseline) POI (12 weeks) Magnitude of change Paired samples test
A 3.44 ± 15.84 2.69± 13.08 2.53 ± 2.76 0.01
SSGARS-2 B 3.88 ± 17.08 2.80 ± 14.76 2.07 ± 2.32 0.01
C 3.47± 17.40 2.82 ± 12.36 2.42 ± 5.04 0.01
D 3.19 ± 16.28 4.01 ± 15.92 2.69 ± 0.36 0.51
Abbreviations: SSGARS-2, stereotypy subscale of Gilliam Autism Rating Scale-Second Edition; Higher scores indicate a higher level
of stereotypy.
Group A: perceptual-motor exercises; Group B: Vitamin D
3
supplementation; Group C: perceptual-motor exercises and Vitamin D
3
sup-
plementation; Group D: control
PRI: pre-intervention; POI: post-intervention.
Data are mean ± SD.
: Significant at p<0.05.
Table 6. Summary of analysis of covariance.
Source Sum of squares d.f Mean square FSig. Effect size
SSGARS-2 Pretests 507.72 1 507.72 111.58 0.010.54
Group 238.09 3 79.36 14.44 0.010.35
Error 432.27 95 4.55
Abbreviations: SSGARS-2: stereotypy subscale of Gilliam Autism Rating Scale-Second Edition.
: Significant at p<0.05.
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
6International Journal of Developmental Disabilities 2018 VOL.0 NO.0
interventions have shown that these interventions can
play a significant role in reducing the stereotypical
behavior in children with autism disorder (Bahrami
et al. 2012, Schmitz et al.2017). These findings show
the importance of physical activities and the formula-
tion of such programs in improving the deficits of chil-
dren with autism disorder. From the results of these
studies, it can be concluded that physical exercises not
only improve the physical status but also decrease the
incompatible patterns of autism behavior (Lancioni and
O’Reilly 1998).
Considering the effect of perceptual-motor exercises
on the improvement of stereotypical behavior in chil-
dren with autism disorder, several mechanisms can be
expressed. The first mechanism is related to the similar-
ity of motor activities and stereotypical behaviors.
According to some researchers, physical activities, as
an effective tool, is effective in reducing strain behav-
iors by providing a similar sensory feedback, through a
more appropriate way (Watters and Watters 1980).
Stereotypic behaviors are often hypothesized to occur
because the behavior itself produces pleasant internal
consequences for the individual (Rapp et al.2004).
This interpretation justifies the emergence and mainten-
ance of stereotypical movements in children with aut-
ism disorder. Based on this justification, stereotypical
movements are maintained through sensory feedback
produced after these movements and these movements
may be replaced or destroyed by movements that create
a similar feedback (Berkson 1983). Therefore, the more
trained movements overlap with mold movements, the
more the effect of these movements will be in reducing
or eliminating mold movements (Watters and Watters
1980). In this regard, Lang et al. (2010) argued that, as
a result of the similarity of physical activities by phys-
ical exercises with the stereotypical behaviors per-
formed by patients with autism disorder, the targeted
activities replace untargeted stereotypical activities in
these individuals (Lang et al.2010). Hence, perceptual-
motor exercises and the involvement of children with
autism disorder in activities such as throwing, receiv-
ing, coordination and balancing movements will
reinforce their intrinsic needs, so that they no longer
need to participate in performing stereotypical behavior
for them.
The second mechanism can be viewed from a neuro-
logical point of view. Studies on patients with autism
disorders have reported abnormal levels of neurotrans-
mitters such as serotonin and dopamine in these indi-
viduals (Volkmar and Anderson 1989). Serotonin plays
a major role in autism, as a neurotransmitter (Boccuto
et al.2013a, Yang et al.2012). According to animal
studies, a decrease in the level of serotonin results in
excessive growth of the cerebral cortex and behavioral
features which are similar to autism (Boylan et al.
2007, Hohmann et al. 2007). Such an evolutionary
defect in individuals with autism suggests that inad-
equate serotonin concentration prevents normal growth
of the brain in these individuals (Boylan et al.2007,
Rokade 2011) . Researchers have also shown that dis-
turbances in neurotransmitters such as serotonin and
dopamine play a role in the stereotypical behavior of
children with autism disorder (Schoenecker and Heller
2001). There is a large amount of evidence that links
stereotypy to the synthesis and metabolism of dopamine
and serotonin. Hyperserotoninaemia has been shown to
have negative correlations with declarative abilities and
self-injuries behaviors in individuals with autism dis-
order (Lanovaz 2011). However, it has been shown that
participation in physical activities can have a significant
effect on dopaminergic and serotoninergic systems and
thus, improve the synthesis of serotonin and dopamine
(Meeusen and De Meirleir 1995) and improve deficits
such as reduction of stereotypical behavior in children
with autism.
Concerning vitamin D supplementation, the results
showed that the application of vitamin D supplementa-
tion for 12 weeks significantly decreased stereotypical
behavior in children with autism disorder. The consist-
ent reduction of stereotypic behaviors of the partici-
pants of the vitamin D supplementation group in our
study may also be explained from a neurochemical
point of view. Vitamin D activates tryptophan hydroxy-
lase 2 (TPH2) in the brain and suppresses the transcrip-
tion of tryptophan hydroxylase 1 (TPH1) in the tissue
outside the blood–brain barrier. In normal subjects,
TPH2 was greater than TPH1, but the levels of TPH1
were higher than autism, which increases gastrointes-
tinal inflammation, weakens the immune system, sero-
tonin neurotransmission and abnormal social behavior
in these individuals. Based on animal studies, lack of
TPH2 in rats’brain serotonin synthesis presented
behavioral symptoms such as autism, including disrup-
tions in social behavior and communication and ten-
dency to stereotypical behaviors (Huang and Santangelo
2008, Kane et al.2012, Yang et al.2012, Boccuto
et al.2013b, Patrick and Ames 2014). In patients with
autism, as well, the further reduction of brain serotonin
is exacerbated by the acute reduction of tryptophan,
leading to symptoms such as repetitive behaviors and
facial recognition patterns that reveal the continued
need for serotonin to modulate these behaviors
(McDougle et al.1996, Daly et al.2012). Researchers
have shown that disturbances of brain key neurotrans-
mitters including serotonin play a role in the mainten-
ance of stereotypic behaviors (Schoenecker and Heller
2001). However, recent experimental studies have
shown that vitamin D can regulate the synthesis and
response to serotonin via TPH2, which can help
improve deficits in children with autism disorder
(Patrick and Ames 2014). In the present study, vitamin
D supplementation may have also increased the levels
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
International Journal of Developmental Disabilities 2018 VOL.0 NO.0 7
of TPH2, which in turn results in more neurotransmis-
sion of serotonin in the brain and improves symptoms,
such as stereotypical behavior in children with autism
disorder. These data provide strong and convincing evi-
dence for a causal role of tryptophan-derived serotonin
in regulating many stereotypical behavior and support
the proposal that supplemental interventions affecting
the serotonin pathway may lead to improvements in a
wide range of stereotypical behavior in ASD (Patrick
and Ames 2014). For these reasons, dietary intervention
with vitamin D would boost brain serotonin concentra-
tions and help prevent and possibly ameliorate some of
the symptoms associated with ASD without
side effects.
Finally, the results of the study showed that a com-
bination of perceptual-motor exercises and vitamin D
supplementation in comparison to each of the groups
alone, led to a further reduction in stereotypical behav-
ior. In relation to the effects of the combination of per-
ceptual-motor Exercises and the consumption of
Vitamin D, several possible mechanisms could be men-
tioned. having adequate levels of Vitamin D may
improve neuromuscular function and ultimately
improve motor performance (Dhesi et al.2004, Lanteri
et al. 2013). Adequate levels of Vitamin D lead to the
creation of better morphological compliance of the
muscles through calcium absorption. This would lead to
better muscular function and activity (Todd et al.
2015). In this way, it could help in the perceptual-motor
Exercises of children with autism. Also, the use of vita-
min D in combined group in the present study has led
to better functioning of children in Motor activities to
perform exercises better and this can be effective in
improving the stereotypical behavior of children with
autism disorder. By the interpretation of the superiority
of the combined interventions, it can be stated that, on
the one hand, the effects of vitamin D supplementation
increased TPH2 and consequently increased neurotrans-
mission of serotonin in the brain (Patrick and Ames
2014), as well as the role of vitamin D in neurotrans-
mitter factors (Kalueff and Tuohimaa 2007). This vita-
min D-mediated production of serotonin would be
critical to produce serotonergic signals during neurode-
velopment, thus shaping the developing brain, and
throughout adulthood, where it plays a critical role in
regulating a variety of brain functions including stereo-
typical behavior. In addition, adequate vitamin D hor-
mone levels would suppress TPH1 expression, which
has important implications for lowering inflammation
and keeping autoimmunity at bay. Vitamin D could
also regulate the synthesis and response to serotonin
and oxytocin, as well as the response to vasopressin,
which could help improve social functioning and
stereotypical behavior in children with autism disorder,
as well. For these reasons, dietary intervention with
vitamin D would boost brain serotonin concentrations
and help prevent and possibly ameliorate some of the
symptoms associated with ASD without side effects.
On the other hand, Vitamin D
3
supplementation also
increased the effects of motor activities on neurotrophic
(Kalueff and Tuohimaa 2007) factors and increased the
learning of different skills (Pilc 2010, Griffin et al.
2011) such as motor coordination, balance and throwing
skills, as well as the replacement of motor activities
with stereotypical behaviors to relieve intrinsic feelings
in children with autism disorder, and improve stereotyp-
ical behaviors in children with autism disorder.
Although this study provides valuable information
about the effects of motor activity and vitamin D on
stereotypic behaviors of children with autism, some of
the limitations of this study should be considered.
Although we did not take any neurochemical and
physiological data in the present investigation, we
speculate that the perceptual-motor exercises and vita-
min D
3
supplementation may improve the synthesis and
metabolism of brain key neurotransmitters and conse-
quently may consistently decrease the stereotypic
behaviors in children with ASD. However, for more
precise conclusion in this context, it's better to investi-
gate neuropsychological and physiological factors using
accurate tools in future. We used fixed vitamin D
3
dos-
ing, but it may be more appropriate to titrate vitamin D
dosing based on baseline 25(OH) D levels and/or body
size. Although we analyzed results based on age (rang-
ing from 6 to 9 years), vitamin D
3
treatment effects
have been reported to be more pronounced in younger
children with ASD (Feng et al.2017) leading to the
suggestion that vitamin D
3
supplementation should start
in early infancy or during gestation (Stubbs et al.
2016). In this context, it is possible that there is a win-
dow of opportunity for adequate vitamin D
3
to provide
neuroprotection and that we included older children in
whom neuronal networks are established and therefore
less likely to benefit from supplementation. In this
study, groups B and D were blinded, but regarding to
the type of perceptual-motor activities intervention,
blinding in groups A and C was not possible. Finally, it
is possible that a higher dose of vitamin D would pro-
duce a greater change in children with ASD stereotyp-
ical behavior.
Conclusion
ASD is a severe, lifelong disorder with serious social
and financial consequences. Insufficient vitamin D due
to genetic and environmental factors is common in chil-
dren with autism spectrum disorder and may be a risk
factor for developing ASD. The results showed that the
combination of perceptual-motor exercises and vitamin
D
3
supplementation has a double effect in comparison
with any of the interventions alone on reducing the
stereotypical behavior of children with autism disorder.
Hence, the use of combined intervention can be an ideal
Hadi Moradi et al. Comparison of the effects of perceptual-motor exercises, vitamin D supplementation
8International Journal of Developmental Disabilities 2018 VOL.0 NO.0
strategy to decrease stereotypical behavior in children
with autism disorder. Vitamin D
3
supplementation can
be a worthwhile effort to reduce symptoms in ASD
with low vitamin levels. In addition, vitamin D
3
supple-
mentation during pregnancy may be preventive as a
preventive means for children with ASD or a measure
to reduce the prevalence of ASD. Supplementation of
vitamin D
3
, which is a confident and cost-effective
form of treatment, may significantly improve outcome
in some children with ASD, especially in younger chil-
dren. However, the exact mechanism how vitamin D
3
contributes to the etiology and treatment of ASD needs
further study. This study would suggest that when chil-
dren with ASD receive direct instructions on targeted
perceptual-motor exercises delivered within an evi-
dence-based framework, the results are positive.
However, considering all the facts in relation to the
roles of Vitamin D
3
and perceptual-motor exercises in
autism, further research is needed to provide a defini-
tive statement on this issue and a clarification of more
precise mechanisms.
Disclosure statement
No potential conflict of interest was reported by
the authors.
ORCID
Mehdi Sohrabi http://orcid.org/0000-0002-
4820-3486
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