Effects of a visual perception-based occupational therapy program on reading and motor skills in children with developmental dyslexia: Single blind randomized cross-over study design
Abstract
This study aimed to examine the effects of a visual praxis-based occupational therapy (VPOT) program on reading and motor skills for children with developmental dyslexia (DD). Forty-two children were included in the study. Additionally, before VPOT, the Reading-Aloud and Reading-Comprehension Test 2 (ORSRC-2) and the Bruininks-Oseretsky Motor-Proficiency-Test-2-Brief Form (BOT2-BF) were applied to the participants. According to the study design, VPOT was applied to two sessions per week for 8 weeks to group A. During this period, group B was accepted as the control group. At the end of these 8 weeks, evaluation tests were applied to both groups. Then, group A was defined as the control group and Group B as the intervention group, and VPOT was applied to Group B. At the end of another 8 weeks, evaluation tests were applied to both groups for the third time. When the final ORSRC-2 results were examined, VPOT was found to be an effective program for improving reading skills. Additionally, when the final BOT2-BF results were examined, VPOT was determined to be effective in improving motor skills (p < 0.05). We believe that it is important to carry out comprehensive studies such as the VPOT program to solve problems in the physical and learning activities of children with DD.
Practitioner Points
- The visual praxis-based occupational therapy program is effective in improving reading and motor skills in children with developmental dyslexia.
- The findings of this study provide an alternative for developing rehabilitation programs for children with developmental dyslexia.
1 INTRODUCTION
According to the classification made by the World Health Organization (WHO) in 2013, a person with developmental dyslexia (DD) is described as having difficulties in reading fluently, phonological awareness, written comprehension, and writing and reading accuracy, while having normal or above normal intelligence and similar socio-cultural opportunities compared with one's peers (Balci, 2017). In 1995, Parkin et al. tried to explain the difficulties experienced by children with DD on a neuropsychological basis using the dual route to reading model (Stewart, 2002). According to this model, reading consists of two stages: word recognition and establishing a sound/letter relationship (coding). Word recognition is a stage of reading that includes the seen word going through visual perception processes (visual memory, shape completion) and becoming interpreted through the relationship between long-term memory and working memory. Establishing sound/letter relationships (coding), on the contrary, is a process that is enabled when the word is not previously known to the reader. In this process, the word becomes interpreted and read with the use of a shape-based interpretation. The visually scanned word goes through visual perception processes and is eventually read on a letter or syllable basis. Especially in this type of reading, one is reading only through phonological connections, not through knowledge- or meaning-based relations. According to the model, any problem in one's visual perception processes can and will cause one's reading problems to increase (Besner & Roberts, 2003; Chang, 2003; Grainger & Ziegler, 2011).
Visual perception is the skill of making things that one sees meaningful through description, transformation and generalization (Akaroğlu & Dereli, 2012; Case-Smith & O'Brien, 2014). Visual perception development is usually completed by the age of 10 (or 12 for spatial perception) (Köse et al., 2019). According to the results of studies that investigate the neurocognitive developmental processes of children with DD, the visual–spatial neurological paths of children with DD usually exhibit atypical patterns of development (Hoeft et al., 2006; Hoeft et al., 2007; Meyler et al., 2007; Richlan et al., 2009). Professionals working in this field have stated that due to these problems, children with DD need additional support in their education to achieve the same level of reading as their peers (Balci, 2019; Saraç, 2014). Another point of interest in the related literature is that children with DD experience problems not only in reading but also in writing, physical activities, team sports and solving mathematical problems/questions within a time limit (Capellini, Coppede, & Valle, 2010; Capellini, Germano, & Padula, 2010; Okuda et al., 2014). Studies that try to explain the underlying reasons for these problems usually focus on cognitive and educational factors. A limited number of studies have stated that these problems are caused by the subpar motor proficiency (such as Fine Motor Precision, Manuel Dexterity, Bilateral Coordination, Balance, Visual Motor Integration) of children with DD (Bruininks & Bruininks, 1977; Capellini, Coppede, & Valle, 2010; Case-Smith & O'Brien, 2014).
The content of rehabilitation and educational support programs aimed at helping the problems of children with DD became more important. In most countries, including Turkey, educational support programs with similar foundations and principles are employed. One of the common features of these programs is that the classes consist mostly of undiagnosed children, and the standard education curriculum is followed. The application of educational support programs usually differs in terms of the additional educational support programs rams aimed at children with DD and the examination systems. Some developed countries have an education system that is dynamically updated based on children's needs, and a child–adolescent psychiatrist, pediatrist, occupational therapist, special education teacher, form teacher, pedagogic, speech and language therapist and audiologist usually participate in the multidisciplinary process (Gersons-Wolfensberger & Ruijssenaars, 1997; Lueder et al., 2009). On the contrary, the educational support programs employed by developing countries, including Turkey, are usually shaped, and directed by special education and form teachers' input regarding the child.
These programs aim to provide support for subjects that are included in the standard education curriculum and that do not involve visual perception and motor proficiency assessment and improvement (Anastasiou & Polychronopoulou, 2009; Özkardaş, 2012). The currently applied educational support programs in Turkey consist of additional one-on-one classes aimed at supporting the standard curriculum. However, the children's reading problems are closely related to their acquired visual perception skills, and the academic problems they experience are usually in parallel with their motor proficiency skills. When this is considered, the need to focus on the contents of educational support programs and the problems that are being addressed in these programs becomes clear. In light of this information, in this study, which was planned with the thought of investigating different rehabilitation applications would be important, it was aimed to investigate the effects of visual praxis-based occupational therapy program (VPOT) on reading and motor skills.
2 METHODS
The study was carried out in Child and Adolescent Mental Health rehabilitation clinics. The study was approved by the University Clinical Research Ethical Committee on 12 November 2020 with the registration number 17/7.
2.1 Participants
All children had a DD diagnosis given by a child psychiatrist according to the DSM-V criteria. Forty-two children who had DD diagnoses were randomly assigned to the study. Before the initiation of the study, all children and their parents were informed about the study, data collection tools, the expected timetable for the assessments as well as the intervention and the expected outcomes. The children and parents who were willing to participate in the study signed an informed consent form.
The inclusion criteria were: (1) Being between 7 and 10 years of age, (2) Having DD diagnosis given by a child psychiatrist according to the DSM-V criteria, (3) Continuing standard education, (4) Having similar visual perception skills (matched with the results from MVPT-3 test). The exclusion criteria were: (1) Having any other diagnosis (ADHD, DCD), (2) Having a speech disorder.
2.2 Procedures
This study was carried out with a randomized, controlled, single-blind, cross-over methodology. To plan the VPOT, Motor-Free Visual Perception Test—3rd Version (MVPT-3) was used before the intervention program. Additionally, before the VPOT, the Oral Reading Skills and Reading Comprehension Test 2nd Version (ORSRC-2) and the Bruninks-Oserestry Motor Proficiency Test 2nd Version, Short Form (BOT2-BF) were applied in order to assess the reading skills and motor skills of the participants, respectively. Following the first assessments, the participants were randomly (groupings to either the study group or the control group were conducted through a simple randomization technique using sequentially numbered and opaque sealed envelopes) divided into two groups: Group A and B. As the study design required, participants in Group A received VPOT for 8 weeks, twice a week with 45-min-long sessions. In this period, participants in Group B were considered as the ‘control group’ and did not receive any kind of intervention. Following the first 8-week period, the assessments were repeated and after that Group A was considered to be the ‘control’ group and the participants in Group B received VPOT for 8 weeks in twice-weekly 45-min sessions. Following the second 8-week period, assessments were applied for a third time and the results were recorded. All assessments were conducted by the second author to ensure blindness and prevent examiner bias (Figure 1).
2.3 Assessments
Assessment of Sociodemographic and Clinical Features of the Children with DD: The sociodemographic and clinical features form was developed by the authors to collect information regarding the factors which can influence reading and motor skills such as age, gender, education and dominant side.
Assessment of the Visual Perception Skills Independently from the Motor Skills of Children with DD: MVPT-3 was developed in 2003 by Colarusso and Hammill. It is a test that can be used with individuals between 4 and 94 years of age and assesses their visual perception skills independently from motor performance. The application of the test takes between 20 and 30 min. The test includes different shapes placed on a white background, and the individual is required to answer various questions regarding the shapes within a multiple-choice design. Correct answers increase the individual's score by one and incorrect ones are worth zero points. The total score is the number of correct answers. The reliability and validity of MVPT-3's Turkish version were investigated by Metin and Aral with excellent results (Cronbach's alpha = 0.85).
Assessment of Oral Reading Skills and Reading Comprehension of the Children with DD: ORSRC-2 was developed by Melekoğlu et al. in 2019 with the aim of assessing reading comprehension, fluent reading skills, reading speed and reading accuracy in children between 7 and 11 years of age. ORSRC-2 gives standardized comparisons regarding the individual's performance against the standard class level. The testing forms of ORSRC-2 consist of A and B segments, which are similar to each other and based on the academic level of the test. The ORSRC-2 contains 13 texts in each segment, making a total of 26 texts. The internal consistency values for the A segment are as follows: 0.97 for reading speed, 0.93 for reading accuracy and 0.60 for reading comprehension. The values for the B segment are 0.97 for reading speed, 0.93 for reading accuracy and 0.73 for reading comprehension. The between-segments reliability scores were 0.92 for reading speed, 0.83 for reading accuracy and 0.82 for reading comprehension. The ORSRC-2 was found to be a usable, valid and reliable tool for assessing reading skills (Melekoglu et al., 2019).
Assessment of Motor Skills of Children with DD: The BOT2-BF consists of 12 items and 8 sub-tests. The application time varies between 15 and 20 min. The maximum possible score is 72. BOT2-BF's validity and reliability for children with SLD were shown by Köse et al. in 2018 (Cronbach's alpha = 0.78). The assessment's clinical utility was shown by Köse et al. and was found to be adequate (Köse, 2018; Kose et al., 2021; Köse, Kara et al., 2022).
2.4 Intervention
Visual Praxis-Based Occupational Therapy Program: The VPOT was applied for a duration of 8 weeks with a twice-weekly frequency of 45-min sessions. The VPOT consists of a total of 6 tasks; 4 of which are stations and the other 2 are activities. In each session, the 6 tasks are implemented with the ‘activity-station-station-station-station-activity’ sequence, without any breaks in between. Before the tasks, the rules and overall idea of the VPOT were explained to the children using clear and understandable language. Some of the hard-to-understand parts of the tasks or any other part of the program was shown to the children by the therapist, and it was made sure that the children understood each and every step. A detailed explanation of the VPOT was reported in the 2021 study by Köse, et al. (2022).
The main aim of the stations is to enable the child to use visual perception skills alongside with motor skills such as fine and gross motor skills, coordination and balance. The main aim of the activities is to enable the children to use visual perception sub-component skills without the usage of motor performance. The tasks and activities of VPOT were made more difficult or easier by changing the complexity of directions regarding the materials' colours and shapes (Table 1).
| Name of the task | Purpose | Application | Grading methods |
|---|---|---|---|
| 1st activity | Improving visual perception skills such as visual memory, figure-ground discrimination and object discrimination | Two photographs are shown. The photographs are chosen from basic concepts such as fruits, vegetables, vehicles, tools and country flags. It is asked from the child that he/she should be able to remember the contents of the photographs during the course of the stations. The child is asked to choose the photographs from a set of other photographs after the final station. |
|
| 1st station | Improving motor skills such as hand-eye coordination, bilateral integration, balance and coordination as well as visual perception skills such as object tracking, figure-ground discrimination and object discrimination. | The child is asked to catch an object that is thrown towards them while jumping up and down. |
|
| 2nd station | Improving gross motor skills such as body perception and lateralization | The child is asked to pass from a confined passage or area |
|
| 3rd station | Improving visual motor skills such as balance, coordination, hand-foot coordination and depth perception | The child is asked to walk from an uneven surface that has materials of different hardness without falling or losing balance. |
|
| 4th station | Improving visual motor skills such as hand-eye coordination, distance perception and visual field screening | The child is asked to hit the target |
|
| 2nd activity | Improving all parameters of motor-free visual perception | The child is asked to transform and build 2D shapes in 3D, using different objects. |
|
2.5 Statistical analysis
The SPSS 23 program was used in all statistical analyses. Continuous variables were reported with mean ± standard deviation (X ± SD) while the categorical or discrete variables were reported with percentages. The normal distribution of the assessment results collected before and after the VPOT were analysed using Shapiro–Wilk test. With the Shapiro–Wilk test, it was found that most variables were not meeting the normal distribution assumptions, and hence, non-parametric assessment methods were used for all analyses. The baseline characteristics of groups regarding the sociodemographic and clinical features were compared with Mann–Whitney U test. In studies with a cross-over design, it is suggested that the Solomon's design is met to analyse the effectiveness of an intervention (Jones & Kenward, 1989). In this experimental design, the planned cross-over groups (Group A and B) are used both as control and intervention groups; thus, it is not expected to find any variance when the repeated measures are compared. According to this information, it is considered to be a Type 1 error to implement the abovementioned analyses. According to the model, it is suggested to use methods that are designed to compare two independent groups. Moving from these suggestions, Wilcoxon signed-rank tests were used to analyse the differences between assessments and the effectiveness of the interventions was analysed with Cohen's effect size calculations. In all statistical results, a p-value of 0.05 or lower was considered to be significant while the effect size calculations were interpreted as the follows: d value less than 0.5 implicates weak effect, d value between 0.5 and 0.8 implicates moderate effect, d value higher than 0.8 implicates strong effect (Cohn, 1988).
3 RESULTS
Forty-two participants that participated in our study were divided into two groups: Group A and B. The participants' mean age was 8.79 ± 0.98. Other demographics are shown in Table 2. Between the two groups, gender (p = 0.181), age (p = 0.95) and MVPT-3 scores (Group A mean MVPT-3 score = 26.80 ± 4.92, Group B mean MVPT-3 score = 24.90 ± 6.76, p = 0.27) were not significantly different.
| X ± SS (Min – Max) | |||
|---|---|---|---|
| A group (n = 21) | B group (n = 21) | Total (n = 42) | |
| Age | 8.76 ± 1.09 | 8.81 ± 0.87 | 8.79 ± 0.98 |
| n (%) | |||
| Gender | |||
| Man | 17 (81%) | 12 (57%) | 29 (69%) |
| Woman | 4 (19%) | 9 (43%) | 13 (31%) |
| Education level | |||
| Second grade | 4 (19%) | 3 (14.3%) | 7 (16.7%) |
| Third grade | 7 (33.3%) | 13 (61.9%) | 20 (47.6%) |
| Fourth grade | 7 (33.3%) | 4 (19%) | 11 (26.2%) |
| Fifth grade | 3 (14.3%) | 1 (4.8%) | 4 (9.5%) |
| Dominant extremity | |||
| Right | 18 (85.7%) | 19 (90.5%) | 37 (88.1%) |
| Left | 3 (14.3%) | 2 (9.5%) | 5 (11.9%) |
3.1 Results regarding oral reading and reading comprehension
At the end of the first stage of the study (after the 8-week intervention period for Group A), individuals in Group A showed significant improvements in reading and reading comprehension levels with significant increases in all ORSRC-2 sub-scores and the ORSRC-2 total score (p < 0.05). On the contrary, individuals in Group B did not show any improvements in ORSRC-2 sub-scores or the total score (p > 0.05) (Table 3). After the second stage of the study (after the 8-week intervention period for Group B), individuals in Group A did not show significant improvements in any of the ORSRC-2 sub-scores or the total score (p > 0.05) while the individuals in Group B showed significant improvements in all ORSRC-2 sub-scores as well as the total score (p > 0.05) (Table 4).
| First evaluation | Second evaluation | p | d | |
|---|---|---|---|---|
| A group | ||||
| Reading speed | 5.14 ± 2.72 | 7.19 ± 2.65 | 0.001** | 0.75**** |
| Correct reading | 5.85 ± 2.08 | 8.28 ± 2.17 | 0.001** | 1.17***** |
| Fluent reading | 4.85 ± 2.76 | 7.90 ± 3.17 | 0.001** | 1.10***** |
| Reading comprehension | 5.14 ± 2.37 | 8.09 ± 2.09 | 0.001** | 1.24***** |
| Total score | 70.14 ± 12.67 | 88.00 ± 14.13 | 0.001** | 1.41***** |
| B group | ||||
| Reading speed | 7.19 ± 2.65 | 7.20 ± 2.22 | 0.905 | 0.02* |
| Correct reading | 8.28 ± 2.17 | 8.20 ± 2.19 | 0.566 | 0.04* |
| Fluent reading | 7.90 ± 3.17 | 7.85 ± 3.15 | 0.317 | 0.01* |
| Reading comprehension | 8.09 ± 2.09 | 8.11 ± 2.09 | 0.782 | 0.07* |
| Total score | 88.00 ± 14.13 | 87.85 ± 14.08 | 0.456 | 0.01* |
- Note: *p < 0.05; **p < 0.001. ***d < 0.20 = weak, ****d = 0.50 moderate, *****d > 0.80 strong. Bold indicates significant values.
| Second evaluation | Third evaluation | p | d | |
|---|---|---|---|---|
| A group | ||||
| Reading speed | 7.19 ± 2.65 | 7.20 ± 2.22 | 0.905 | 0.02 |
| Correct reading | 8.28 ± 2.17 | 8.20 ± 2.19 | 0.566 | 0.04 |
| Fluent reading | 7.90 ± 3.17 | 7.85 ± 3.15 | 0.317 | 0.01 |
| Reading comprehension | 8.09 ± 2.09 | 8.11 ± 2.09 | 0.782 | 0.07 |
| Total score | 88.00 ± 14.13 | 87.85 ± 14.08 | 0.456 | 0.01 |
| B group | ||||
| Reading speed | 6.00 ± 2.82 | 8.04 ± 2.74 | 0.001* | ** |
| Correct reading | 6.42 ± 2.31 | 9.14 ± 2.47 | 0.001* | 1.17***** |
| Fluent reading | 6.09 ± 3.12 | 9.09 ± 3.22 | 0.001* | 0.96***** |
| Reading comprehension | 5.09 ± 2.14 | 7.80 ± 2.48 | 0.001* | 1.27***** |
| Total score | 73.28 ± 14.93 | 90.71 ± 76.23 | 0.001* | 1.17***** |
- Note: *p < 0.05, **p < 0.001. ***d < 0.20 = weak, ****d = 0.50 moderate, *****d > 0.80 strong. Bold indicates significant values.
3.2 Results regarding the motor proficiency levels
At the end of the first stage of the study (after the 8-week intervention period for Group A), individuals in Group A showed significant improvements in all BOT2-BF scores except for Hand Skills, Balance and Endurance sub-scores (p < 0.05) while the individuals in Group B did not show significant improvements in any of the sub-scores or the total score (p > 0.05) (Table 5). After the second stage of the study (after the 8-week intervention period for Group B), individuals in Group A did not show significant improvements in any of the BOT2-BF sub-scores or the total score while the individuals in Group B showed significant improvements in all BOT2-BF scores except for Hand Skills, Balance and Endurance sub-scores (p < 0.05) (Table 6).
| First evaluation | Second evaluation | p | d | |
|---|---|---|---|---|
| A group | ||||
| Fine motor rrecision | 3.19 ± 0.92 | 3.85 ± 1.15 | 0.004* | 0.72* |
| Fine motor integration | 4.90 ± 1.51 | 7.09 ± 2.09 | 0.001** | 1.45***** |
| Manuel dexterity | 2.52 ± 0.81 | 2.76 ± 0.83 | 0.059 | 0.29 |
| Bilateral coordination | 2.61 ± 1.16 | 3.38 ± 1.28 | 0.001** | 0.66 |
| Balance | 2.23 ± 0.70 | 2.38 ± 0.92 | 0.317 | 0.20 |
| Running speed and agility | 2.85 ± 1.10 | 3.80 ± 1.50 | 0.001** | 0.86***** |
| Upper-limb coordination | 4.28 ± 2.12 | 6.52 ± 1.99 | 0.001** | 1.05***** |
| Strength | 3.19 ± 1.12 | 3.76 ± 2.09 | 0.082 | 0.51 |
| Total score | 26.28 ± 4.89 | 33.76 ± 6.46 | 0.001** | 1.53***** |
| B group | ||||
| Fine motor precision | 2.90 ± 0.83 | 2.90 ± 0.83 | 0.936 | 0.01 |
| Fine motor integration | 6.23 ± 1.64 | 6.23 ± 1.64 | 0.855 | 0.09 |
| Manuel dexterity | 2.80 ± 0.74 | 2.80 ± 0.74 | 0.565 | 0.06 |
| Bilateral coordination | 4.00 ± 1.26 | 3.90 ± 1.13 | 0.157 | 0.08 |
| Balance | 2.61 ± 0.59 | 2.66 ± 0.57 | 0.317 | 0.08 |
| Running speed and agility | 3.71 ± 1.05 | 3.71 ± 1.05 | 0.945 | 0.27 |
| Upper-limb coordination | 5.90 ± 1.89 | 5.52 ± 1.43 | 0.23 | 0.20 |
| Strength | 2.14 ± 0.72 | 2.23 ± 0.76 | 0.157 | 0.13 |
| Total score | 30.47 ± 4.50 | 30.14 ± 4.11 | 0.100 | 0.07 |
- Note: *p < 0.05, **p < 0.001. ***d < 0.20 = weak, ****d = 0.50 moderate, *****d > 0.80 strong. Bold indicates significant values.
| Second evaluation | Third evaluation | p | d | |
|---|---|---|---|---|
| A group | ||||
| Fine motor precision | 3.85 ± 1.15 | 3.86 ± 1.15 | 0.985 | 0.00 |
| Fine motor integration | 7.09 ± 2.09 | 7.14 ± 2.12 | 0.317 | 0.02 |
| Manuel dexterity | 2.76 ± 0.83 | 2.74 ± 0.83 | 0.855 | 0.00 |
| Bilateral coordination | 3.38 ± 1.28 | 3.42 ± 1.32 | 0.388 | 0.04 |
| Balance | 2.38 ± 0.92 | 2.39 ± 0.88 | 0.656 | 0.00 |
| Running speed and agility | 3.80 ± 1.50 | 3.85 ± 1.55 | 0.255 | 0.03 |
| Upper-limb coordination | 6.52 ± 1.99 | 6.41 ± 2.06 | 0.157 | 0.05 |
| Strength | 3.76 ± 2.09 | 3.80 ± 2.06 | 0.317 | 0.02 |
| Total score | 33.76 ± 6.46 | 34.00 ± 6.76 | 0.102 | 0.04 |
| B group | ||||
| Fine motor precision | 2.90 ± 0.83 | 3.80 ± 0.87 | 0.004* | 1.09***** |
| Fine motor integration | 6.23 ± 1.64 | 8.19 ± 1.03 | 0.003* | 1.19***** |
| Manuel dexterity | 2.88 ± 0.74 | 3.00 ± 0.89 | 0.46 | 0.25 |
| Bilateral coordination | 3.90 ± 1.13 | 5.00 ± 1.41 | 0.003* | 0.96***** |
| Balance | 2.66 ± 0.57 | 2.76 ± 0.53 | 0.317 | 0.16 |
| Running speed and agility | 3.71 ± 1.05 | 4.61 ± 1.68 | 0.005* | 0.86***** |
| Upper-limb coordination | 5.52 ± 1.43 | 7.66 ± 1.93 | 0.001** | 1.49***** |
| Strength | 2.23 ± 0.76 | 2.33 ± 0.79 | 0.317 | 0.12 |
| Total score | 30.14 ± 4.11 | 37.38 ± 5.11 | 0.001** | 1.76 |
- Note: *p < 0.05, **p < 0.001. ***d < 0.20 = weak, ****d = 0.50 moderate, *****d > 0.80 strong. Bold indicates significant values.
4 DISCUSSION
This study aims to investigate the effects of the VPOT on reading and motor performance problems in children with DD. According to our results, VPOT was found to be an effective intervention program to improve reading skills such as reading comprehension, reading accuracy and reading fluency; as well as motor skills such as balance, coordination and fine motor integration.
E. J. Ashman and G. S. Gronseth have classified studies within the health and healthcare field according to their quality level based on their design, description of the prognosis and generalizability. The classification levels ranged between 1 (best possible level of evidence) and 4 (worst possible level of evidence), with randomized cross-over trials ranked in the first level (Ashman & Gronseth, 2012). In addition, B. A. Wilson et al. have stated that in trials concerning cognitive, motor or emotional skills—which are susceptible to change over time—time might become a confounding variable regarding the possible changes that occur over time in the control group. It was suggested that in order to control for a time as a confounding variable, researchers may employ a randomized cross-sectional design, which will help improve the reliability and overall quality of their evidence (Wilson et al., 2013). The methodological design in our study was developed based on the related literature.
Scott et al. suggested that visual perception skills are connected to motor planning skills through special paths within the nervous system. They stated that it would be important to investigate the relationship between these two systems and plan interventions that are aimed at both visual perception and motor skills (Scott & Schoenberg, 2011). According to the results of E. Murray's study, which investigated the relations between object discrimination, spatial position and motor planning skills, children with DD who have motor planning problems exhibit lower performance in visual perception skills. In addition, it was said that it would be more effective to include both visual perception and motor skills in an intervention program than including only one of these, since children with dyslexia experience problems in many different areas that are interconnected (Domrath, 1968). Considering the abovementioned focus points of the literature, the intervention program in our study was designed to include visual perception and motor skills on a systematic visual praxis basis.
R. L. Peterson et al. stated in their study that children with dyslexia have a lower level of activity in their occipitotemporal lobe compared with their peers (Peterson & Pennington, 2015). In their study which explains strategies to plan interventions for reading problems, Fuchs et al. stated that if the interventions include both cognitive (visual perception, auditory discrimination, attention) and motor components, they are more effective in improving reading skills (Fuchs & Fuchs, 2006). According to the results of our study, the VPOT program, which was designed based on the literature emphasizing the physiological features of children with dyslexia and learning principles, was found to be an effective method for improving all reading skills (reading speed, reading accuracy, reading fluency, reading comprehension) of children with DD.
It is noted that studies investigating the process of learning to read in DD suggest assessing and addressing reading speed and reading accuracy problems alongside addressing the children's visual perception problems. It has been reported that children with DD experience problems in pronouncing sounds or words when reading fast. This observation has subsequently been explained by Amitay et al. using the magnocellular hypothesis (Amitay et al., 2003). According to this hypothesis, the flow of information between the magnocellular and parvocellular systems is related to visual perception skills and pronouncing words fast and accurately in children with DD. In this context, it was demonstrated that visual perception interventions can improve reading speed and accuracy.
Dosher et al., on the contrary, have studied reading speed and accuracy from the perspective of visual confusion and visual discrimination. In their study, they stated that using high-contrast materials in reading interventions would decrease visual confusion and therefore influence performance positively (Dosher & Lu, 2005). In addition, Bray et al. showed in their review on reading and spelling skills of children with dyslexia that using multi-sensorial and multi-faceted intervention programs are more effective in improving pronunciation accuracy and spelling skills (Bray et al., 2021). According to our study's results, the VPOT effectively improved reading speed and accuracy.
In their study investigating the relationship between visual perception and reading skills, Rasinski and Samuels found that there was a positive relationship between reading fluency and visual perception (Rasinski & Samuels, 2011). Fredericks et al., by comparison, demonstrated that a sensory-motor-based developmental movement program was effective in improving reading fluency (Fredericks et al., 2006). In studies on reading fluency, it was found that reading fluency has a direct relationship with visual perception skills, and consequently, it has been suggested that intervention programs should be planned and designed taking this relationship into account (Ehri, 2005; Lee & Yoon, 2017). Considering these findings, it is thought that the evidence regarding the VPOT's effectiveness in promoting the reading fluency of children with dyslexia would contribute greatly to the existing body of literature.
In studies investigating the reading comprehension of children with dyslexia, the existing interventions consist of three strategies: increasing the children's vocabulary (increasing the usage of notional words and visual–auditory education approaches), self-correcting (reviewing the entire text, answering questions regarding the text while reading, extending attention to the entire text, following multiple directives) and storification (using pictures, coding techniques, etc.) (Collins & Cheek, 1999; Pürsün & Hakan, 2020). Using these strategies was found to be an effective intervention method for increasing the reading comprehension skills of children with DD (Alturki, 2017; Chalk et al., 2005; Crabtree et al., 2010; Huesman Jr & Frisbie, 2000; Stagliano & Boon, 2009). While the VPOT is on par with the example strategies and intervention methods in the literature (teaching different notional dimensions and using multiple directives), it is the first example in the field of using visual and motor components collaboratively. In this context, this study presents a new and alternative method for increasing the reading comprehension skills of children with DD.
According to their review of interventions for improving the visual motor skills of children with developmental disorders, Hong et al. stated that occupational therapy interventions were effective in increasing fine and gross motor skills for children with various diagnoses (Hong & Kim, 2010). In our study, VPOT was also found to be effective in increasing fine and gross motor skills, including motor accuracy, fine motor integration, bilateral coordination, upper extremity coordination and motor proficiency skills (except for hand skills, balance and endurance). These results are in accordance with previous studies and emphasize the effectiveness of such intervention on motor proficiency skills.
Bishop et al. showed that occupational therapy interventions were effective in increasing hand skills for children with DD (Bishop & Pangelinan, 2018). Additionally, in their article investigating the evidence levels of studies on intervention methods aimed at the motor skills of children with developmental coordination disorder, Prekson et al. found that there was a high level of evidence demonstrating that the interventions were effective in increasing hand skills (Preston et al., 2017). Contrary to the studies in the literature, the VPOT programme was not found to be effective in increasing the hand skills of children with DD. Three reasons for this contradiction between our study and the existing literature are thought to exist. First, the BOT2-BF is a brief form that is specifically designed to be highly practical but not highly accurate; thus, it assesses hand skills with only one parameter. Second, the parameter used to assess hand skills was time limited. Third, other attention-related factors might have played a confounding role because of the time limit. We believe that this contradiction between our study and the existing literature shows the importance of using a more detailed hand assessment in future studies.
In their study investigating the relationship between motor control and phonology in children with reading problems, Ramus et al. showed that balance is closely related to automatic learning and motor control (Ramus et al., 2003). Paralelly, Kashfi et al., demonstrated that a motor skills-based programme developed by them was effective in improving balance in children with learning disabilities (Emami Kashfi et al., 2019). However, according to the results of our study, the VPOT programme was not effective in improving balance skills. We believe that this contradiction is attributable to balance being a highly complex skill that can be improved by specifically focused interventions and can only be reliably measured with balance-focused instruments.
Wall et al. stated that motor skill development ends between 7 and 12 years of age and that the development processes for these skills are not as straightforward as previously thought, with the development processes having an age-based cumulative advancement. They also stated that motor skills are divided into two major groups: locomotor skills (push-ups, moving in general) and ball skills (throwing, catching, releasing, activities that require bilateral skills) (Wall, 2004). Parush et al. have studied the effectiveness of an occupational therapy intervention on the visual motor skills of children with DD. The intervention was applied in 90-min sessions once a week for 7 months, with the results showing the intervention to be effective in increasing gross motor skills (Parush & Hahn-Markowitz, 1997). Unlike the studies in the literature, our study yielded no significant differences in the BOT2-BF endurance subtest after the intervention. A possible explanation for this dissimilarity is that the applied intervention duration was not lengthy enough to facilitate a meaningful improvement since gross motor skills have a cumulative and slow development.
This study reported motor proficiency outcomes with assessment results regarding fine and gross motor integration, balance and coordination, all of which helped show the effects of the VPOT on motor skills. However, even though the VPOT was an intervention program based on visual praxis, our results do not include detailed outcome measurements related to visual motor skills, which is a limitation concerning the study's ability to show the effects of the VPOT on visual motor skills. Future studies should conduct outcome measurements concerning these skills to offer meaningful contribution to the body of evidence surrounding the VPOT.
5 CONCLUSIONS
The fact that reading problems and motor skill problems experienced by children with DD are so closely related makes it necessary to design multi-faceted intervention programs. In this context, this study is significant for clinicians, members of academy and families in terms of showing that VPOT, an intervention method that includes both motor and visual skills, is effective in increasing reading as well as motor skills.
AUTHOR CONTRIBUTIONS
Barkın K and Koray K carried out the literature survey, applied for ethical approval and contributed to the development of the data collection methods and analysis plans. Barkın K applied the visual-based occupational therapy program. Mine U undertook the data collection process which is the repeated evaluation process. Ege T and Sedef Ş contributed to the analysis process, interpreted the data and contributed to the development of the text. All the authors reviewed and edited the text and eventually approved of the final version.
CONFLICT OF INTEREST STATEMENT
The authors declare that they have no conflict of interest.
ETHICS STATEMENT
Health Sciences University, Antalya Research and Education Hospital's Clinical Research Ethical Committee on 12.11.2020 with the registration number 17/7.
CONSENT TO PARTICIPATE
Written consent was obtained from all participants regarding their participation in this study.
CONSENT FOR PUBLICATION
All participants were informed about the study and all possible future applications with the data (including publication in a scientific journal) obtained from them before giving written consent.
Open Research
DATA AVAILABILITY STATEMENT
The data were collected after obtaining written informed consent from the participants. This informed consent included that the participants' personal information and data would not be shared with any person or institution under any circumstances except for the case of ethical reviewing conducted by ethical committees. This measure was necessary since there were variables that are not suitable for deidentification (i.e. place of residence, age and gender) in this study. Unveiling those participants' personal information was not something we found to be on par with ethical codes.
