Using Structured Instruction and Visuospatial Enhancements for Teaching Solid Shapes’ Properties to Primary Students with Specific Learning Disabilities or Attention Deficit Hyperactivity Disorder

This study compared the effectiveness of two instructional interventions for teaching geometric solid shapes to students with Specific Learning Disabilities (SLD) or Attention Deficit Hyperactivity Disorder (ADHD). The first used the Goal-oriented Instruction for Conscious Learning (GICL), a structured model incorporating Systematic Explicit Instruction with goal-setting based on Specific, Measurable, Achievable, Relevant, Time-bound SMART framework. The second combined GICL with visuospatial support. Fifty sixth-grade Greek students participated in a quasi-experimental design with pre- and post-assessments. Both the control group (GICL) and the experimental group (GICL and visuospatial supports) showed significant improvement in distinguishing solid shapes, identifying properties and calculating volume. However, no significant difference was found in the magnitude of the improvements between the two interventions. The findings discussed the effectiveness of GICL and the potential role of visuospatial support for students with SLD or ADHD.

Introduction

The correct identification of geometric solid shapes and comprehension of their properties are complex tasks presupposing well-developed visuospatial and kinesthetic perception, strong visual- and verbal-working memory, mastery of geometric and arithmetic basic facts and procedures, mathematical reasoning and proof skills (Mammarellaet al., 2019; Zhang, 2017). Research shows that various groups of struggling students, including those with Specific Learning Disabilities (SLD) or Attention Deficit Hyperactivity Disorder (ADHD), face considerable challenges in meeting the demands of solid shapes learning. These student groups require specialized interventions to overcome their difficulties and ultimately succeed in learning geometry (Vaughn & Linan-Thompson, 2003).

Literature Review

Difficulties in Learning Geometric Solid Shapes

A considerable number of students struggle with foundational geometric concepts and perform at below-average level on tasks concerning solid shapes (Bizzaroet al., 2018; Giofrèet al., 2014). Among these students, those presenting SLD or ADHD stand out because of their considerable number and the fact that they are usually integrated into mainstream classrooms and face the same academic expectations as their peers do. Nonetheless, there is evidence that, when trying to meet the demands of solid shapes learning, students with SLD or ADHD may present patterns similar to those observed in younger students, in the sense that they may prioritize attributes such as color and direction over geometric properties, such as length and width. Furthermore, they may confuse, omit, replace, misunderstand, unnecessarily add, distort or completely ignore the various prerequisites and constituent dimensions of solid shape knowledge (Agaliotiset al., 2011; Castro & Huamanchahua, 2021; Zhanget al., 2022). Common tasks they struggle with include identifying, understanding, measuring and applying solid shapes’ properties, as well as using the correct terminology (Kirpouiki & Agaliotis, 2024; Hord & Xin, 2015; Kang & Zentall, 2011; Zhanget al., 2014, 2022). These difficulties are linked to issues in perception, memory, attention, processing, abstract thinking and visuospatial abilities (Kang & Zentall, 2011; Marita & Hord, 2017).

Research Data on Teaching Geometry to Students with SLD or ADHD

The considerable difficulties presented by students with SLD or ADHD, when dealing with solid shape learning-necessitate their support through targeted instruction, tailored to their specific needs-in order for them to achieve meaningful progress (Kozulin & Kazaz, 2017; Papadam & Agaliotis, 2021). In trying to specify strategies and approaches that could help students with SLD or ADHD in succeeding in Geometry, researchers have tested various instructional means and tools such as: educational technology (Cihak, 2009; Satsangiet al., 2020), tactile representations (Casset al., 2003), visual techniques (Zhanget al., 2014) and multiple representations (Hord & Xin, 2015; Kozulin & Kazaz, 2017; Zhang, 2017). Meta-analyses by Bergstrom and Zhang (2016) and Liuet al. (2021) showed that the most effective results come from combining Systematic Instruction with multiple representations and explicit lesson plans.

However, not all pertinent problems have been through the aforementioned instructional combinations or individual instructional means. Thus, the researchers sought additional support for students struggling with geometric tasks. In this context we studied (a) whether visuospatial ability, which is considered a key parameter of geometric learning, could be enhanced and (b) whether improvements in visuospatial tasks would transfer to geometric learning. It was found that, while most interventions aimed at improving visuospatial skills yielded positive outcomes, it remained uncertain whether visuospatial gains may be effectively transferred to geometric achievements, especially in the case of students with persistent learning problems, like those with SLD or ADHD (Bergstrom & Zhang, 2016; Mammarellaet al., 2019).

Considering the increasing significance of specifying effective support for students with SLD or ADHD in the context of Inclusive Education, it is crucial to explore whether combining visuospatial enhancements with instructional interventions can create powerful tools that can leverage the strengths of both approaches (Liuet al., 2021).

Aim of the Study and Research Questions

International research on effective geometry instruction for students with SLD or ADHD has revealed several limitations that hinder its broad application. Notably, much of the research has focused on students aged 12 years and older, primarily addressing SLD, while often neglecting younger learners and students with ADHD. Additionally, many studies tend to focus on a single instructional approach, with limited comparative analyses of different strategies. Furthermore, a growing body of evidence suggests the need for interventions that integrate both explicit instructional methods and cognitive enhancements (e.g., Zhanget al., 2022).

Hence, this study focused on evaluating two distinct interventions. The first intervention is based on a model rooted in Systematic Explicit Instruction, while the second combined this model with a program aimed at enhancing visuospatial ability. The instructional model used is called “Goal-oriented Instruction for Conscious Learning” (GICL), and it is a structured–instruction model including the following phases: (a) Specification of SMART (Specific, Measurable, Achievable, Relevant, Time-bound) goals, which are presented and explained to the student at the beginning of the intervention, (b) Systematic integration of new content with prior knowledge, with the former resulting from the school curriculum and the latter being defined through Educational Assessment that precedes intervention, (c) Acquaintance of the student with the new material through multiple-modes of knowledge representation and via examples and counterexamples, (d) Guided practice on the goal content, (e) Instructional goal reminder and knowledge review, (f) Independent practice on goal content, (g) Evaluation of instructional results and decision on the continuation of the intervention (Agaliotis, 2023). Evidently, GICL incorporates constructs and practices with proven value and power, such as prioritizing foundational knowledge, linking new information to prior learning, aligning activities with instructional objectives, incorporating instructional scaffolding, and implementing formative assessment, to ensure sustained student progress. Support for GICL can be found both in international research (e.g., Cheryanet al., 2014; Mason & Otero, 2021; Slavin, 2013) and in studies that used a previous version of GICL, which proved to be highly effective in supporting primary and secondary students with SLD or ADHD who presented difficulties in arithmetic (Agaliotis & Teli, 2015, 2016; Papadam & Agaliotis, 2021) or reading (Kirpouiki & Agaliotis, 2024, 2025). However, the potential effectiveness of the GICL model in terms of geometry has not yet been explored.

Despite their distinct etiologies, Specific Learning Difficulties (SLD) and Attention-Deficit/Hyperactivity Disorder (ADHD) often exhibit substantial cognitive overlap—particularly in attention, working memory, and visuospatial processing—core domains for geometry learning. This convergence underscores the rationale for designing and evaluating interventions that address both groups concurrently.

Considering all the aforementioned findings, aspects, and approaches, the present study sought to answer the following questions:

1. To what extent does a GICL–based intervention improve the performance of primary students with SLD or ADHDin identifying solid shapes, distinguishing properties, constructing shapes using nets, and calculating volume?

2. Does the combination of a GICL–based intervention with visuospatial enhancements have an increased effect on the ability of students with SLD or ADHD to identify solid shapes, distinguish their properties, construct shapes through nets and calculate volume, compared with the intervention that only uses GICL?

3. How do the geometric performances of primary students with SLD and ADHD differ under the same instructional conditions?

4. Does student performance differ between the SLD and ADHD groups based on whether they received GICL-only instruction or GICL combined with visuospatial enhancements?

Materials and Methods

Research Method

In this study, a quasi-experimental method was employed to administer two educational interventions and to estimate their impact on participants’ geometric knowledge. The study was approved by the Ethics Committee of the University with which the authors were affiliated. Permission to enter school units was accorded by regional education authorities.

Participants

Sampling Procedures

Eligibility for students’ participation was determined according to the following criteria:

• A formal diagnosis of SLD (in Reading, Writing, or Mathematics) or ADHD (any subtype) -issued by certified state agencies (e.g., public diagnostic centers) within 12 months prior to study onset.

• Prior exposure to standard curriculum-based geometry instruction, with no subject-specific support from either general or special education staff.

• Regular participation in Resource Room instruction, as stipulated by diagnostic recommendations.

• Age-appropriate visuospatial functioning and a score below 50% on the initial geometry assessment –indicated a marked difficulty in the targeted area of learning.

After verifying the above criteria, students who fully met them were included in the intervention. Exclusions were applied to cases lacking formal diagnosis, presenting comorbid conditions, beyond SLD/ADHD, or exhibiting difficulties attributable to socio-cultural or economic factors rather than to neurodevelopmental causes.

Participant Characteristics and Sample Size of Students

The sample included 30 students with SLD and 20 with ADHD, aged 11–12, from sixth grade in central and northern Greece, attending Resource Rooms for 3–4 hours weekly. Parental consent was obtained from all participants. Participants were reassigned between the experimental and control groups using SPSS based on initial cognitive and learning measures, ensuring no significant pre-existing differences. This procedure ensured internal validity, allowing post-intervention effects to be attributed to the intervention rather than group disparities. Participant characteristics are presented in Table I.

Table I. Participants’ Characteristics

Groups	SLD	ADHD	Total
	N	N	N
Male	21 (60%)	14 (40%)	35(100%)
Female	9 (60%)	6 (40%)	15 (100%)
Control group	15(60%)	10 (40%)	25 (100%)
Experimental group	15 (60%)	10 (40%)	25 (100%)

Measures

Research data were collected using both researcher-made and standardized assessment tools.

Researcher-Made Test

The informal tool, designed to evaluate students’ understanding of three-dimensional geometric solids, was based on a Curriculum-Based Assessment (Agaliotis, 2023; Galletta, 2013). Relevant content domains were derived from the Greek National Curriculum for the first five grades of primary school, with a focus on solid geometry. Key instructional components were identified from the textbooks, and the corresponding tasks were developed accordingly. Target shapes included cubes, pyramids, rectangular prisms and spheres.

The task design was informed by established instruments measuring Van Hiele levels of geometric reasoning (e.g., Patkin, 2014; Tieng & Eu, 2018; Usiskin, 1982) originally developed for 2D shapes. These tools were adapted to the 3D domain, while preserving the original structure, task types, and cognitive demands. In specific:

• Shape presentation: 3D shapes were displayed in orientations, sizes, and visual formats similar to 2D shapes in standardized tests.

• Task structure: The core task requirements (e.g., sorting, pointing, drawing, and measuring) remained consistent.

• Assessment scope: The tasks examined the recognition, classification, construction, and measurement (e.g., volume) of solid shapes.

Sample tasks included 1) identifying examples and excluding non-examples of solid shapes, 2) selecting correct properties of given solids, 3) constructing nets of 3D shapes, 4) identifying common geometric features and describing them with appropriate vocabulary and 5) calculating volume. The researcher-made tool was piloted with 10 students before its application. Tools used for the final assessment, which followed the interventions, were designed exactly like those of the initial assessment, differing only in numerical information, colors and orientations of solid shapes. Special measures were taken to minimize writing demands, thus facilitating the participation of students with attention difficulties. Students completed the tool independently. Scoring was as follows: each correct solution earned 5 points, with a maximum score of 25.

Standarized Tests

Visuospatial ability was assessed using the English version of the Rey-Osterrieth Complex Figure Test (ROCF) (Corwin & Bylsma, 1993; Rey & Osterrieth, 1993), as this tool has not yet been standardized in Greece. Participants were required to copy the complex ROCF shape as accurately as possible, earning a maximum score of 36 (Rey & Osterrieth, 1993).

Structure οf the Interventions

Control Group Intervention

The instructional intervention used to support the control group was based on the Goal-oriented Instruction for Conscious Learning (GICL) model, which is a structured-instruction method that combines: explicit instruction, clear goal-setting, consideration of prerequisite knowledge, multiple modes of knowledge representation, active learner engagement, gradual learner autonomy and evaluation of instructional outcomes (Agaliotis & Teli, 2016; Aggelopoulos & Agaliotis, 2021; Kirpouiki & Agaliotis, 2024, 2025).

Each phase of the GICL model had the following features:

1st phase: Formulating a SMART geometric goal for each lesson and communicating it to the students before the instruction (e.g., “Students label correctly at least 4 out of 5 cubes visually presented among 10 other solid shapes in no more than 40 seconds”).

2nd stage: Establishing connections between previously acquired geometry-relevant knowledge and new geometric concepts through expository advance organizers (e.g., relating geometric concepts to everyday objects such as a can to explain cylindrical shapes).

3rd stage: Explicitly teaching new geometric knowledge for each unit using clear demonstrations, multiple representations, and appropriate student explorations.

4th stage: Guiding students in applying the new geometric knowledge and showing understanding of its specifics while systematically providing corrective feedback. The instruction returned to previous GICL stages in case of a student’s inability to meet the demands of the tasks.

5th stage: Reminding the lessons’ goal, reviewing the newly acquired geometric knowledge and reinforcing its applicability and connection to other knowledge.

6th stage: Having students practice independently the use of the newly acquired geometric knowledge in the context of appropriate tasks.

7th stage: Εvaluating student final attainment and deciding on the continuation of the instructional program.

The intervention consisted of twelve 35–40-minute lessons over five weeks (three lessons per week for the first two weeks and two lessons per week in the following three weeks).

The initial six units focused on prerequisite knowledge essential for understanding the properties of solid shapes (e.g., edges, vertices, points, sides, angles, types of geometric shapes, and their correspondence with solid shape faces). The subsequent six units covered the four fundamental geometric solid shapes (e.g., types of shapes [cubes, pyramids, parallelepipeds and spheres], shape construction, number of sides or faces, angles, vertical lines).

Experimental Groups’ Intervention

The intervention for the experimental group combined the GICL model and visuospatial supports. Visuospatial training focused on improving visual and spatial processing and addressing the deficiencies identified by the initial ROCF test. The Modified Complex Taylor Figure (MTCF) (Hubley & Tremblay, 2002) was used for the training, which incorporates practice on copying complex designs with varied angles, vertical and parallel lines and interconnected shapes. Students practiced isolating elements (e.g., distinguishing triangular from square shapes), rotating complex figures, and identifying internal features. Visuospatial training adhered to GICL principles, including pre-scripted organizers, detailed teacher presentations, student explorations, systematic and independent practice and a final assessment of the visuospatial goal. This integration was intended to provide a complementary effect, addressing both cognitive processing (visuospatial skills) and explicit geometric knowledge instruction. Such combination targets the multifaceted difficulties faced by students with SLD and ADHD, who often exhibit overlapping deficits in attention, working memory, and spatial reasoning. Owing to the addition of visuospatial training, the intervention for the experimental group exceeded that for the control group by two hours.

Statistics and Data Analysis

Shapiro-Wilk tests revealed a non-normal distribution for certain variables, prompting the use of non-parametric tests (Mann-Whitney U, Kruskal-Wallis, Wilcoxon Signed Rank Tests). Effect sizes were calculated using the formula: r = Z$\surd \text{N}$, where N is the total sample size (50) and Z represents the standardized score deviations (Fritzet al., 2012). Power analysis indicated that a minimum sample size of n = 24 would be required to achieve a statistical power of 0.98 (α = 0.05, two-tailed), ensuring a 98% probability of detecting a true effect. The actual sample used in the study (N = 50) exceeded this threshold, further strengthening the reliability of the findings.

Results

Pre-Intervention Data

The pre-intervention assessment revealed no statistically significant differences between the two groups regarding solid shapes knowledge (U = 283.000, z = −0.585, p = 0.559) and visuospatial ability (U = 283.000, z = −0.585, p = 0.559). Thus, potential post-intervention differences in solid shapes knowledge could be attributed to the interventions per se, rather than to pre-intervention group disparities.

Comparisons between Initial and Final Students’ Performance

Analyses comparing the scores of the initial and final assessments of the two groups revealed statistically significant improvements for both the control and the experimental groups with regard to the tasks of the solid shape tool (control group: z = −4.374, p = 0.000, r = 0.62; experimental group: z = −4.374, p = 0.000, r = 0.62). There were no significant differences in final performance between the two groups (U = 115.000, z = −3.842, p = 0.368). Evidently, the incorporation of visuospatial enhancement into the GICL intervention did not result in statistically significant variations in final performance. As shown in Table II, both students with SLD and those with ADHD more than doubled their initial performance following the intervention. Despite the large effect sizes observed (r = 0,62), no statistically significant differences were observed between the groups.

Table II. Comparative Presentation of Overall Results (Pre and Post Interventions)

Pre intervention	Post intervention	Degree of improvement	Effect size
Mean	Mean	Percent %	r
Control group
10.11 (3.81)	22.11 (2.24)	119,0%	0.62
Experimental group
9.87 (2.41)	22.09 (3.04)	123.8%	0.62

As shown in Tables III and IV, participants in both the control and experimental groups showed notable gains in identifying the properties of solid shapes, constructing them from nets, recognizing common features, and calculating volume, indicating the positive impact of the interventions. In these tasks, participants exhibited significant improvement, exceeding 100%, suggesting a two-fold increase in initial performance. This trend remained consistent across measures of effect size for both the GICL intervention alone and when combined with visuospatial reinforcement.

Table III. Detailed Data about the Performance of Control Group

Tasks in solid shapes’ tool	Control group means		Degree of improvement%	Effect size
	Pre	Post
Identification of the type of solid shapes	3.27 (0.76)	4.52 (0.56)	39%	0.54
Distinguishing properties of each solid shape	1.32 (1.51)	4.05 (0.69)	206%	0.62
Construction of solid shapes through nets	1.52 (0.58)	4.32 (0.80)	184%	0.62
Distinguishing solid shapes with common features	1.82 (1.26)	4.00 (0.89)	120%	0.60
Calculating volume of solid shapes	1.38 (0.60)	3.76(0.80)	172%	0.63

Table IV. Detailed Data about the Performance of Experimental Group

Tasks in solid shapes’ tool	Experimental group Means		Degree of improvement %	Effect size
	Pre	Post
Identification of the type of solid shapes	3.04 (1.20)	4.66(0.50)	53%	0,56
Distinguishing properties of each solid shape	1.49 (0.90)	4.24 (0.60)	184%	0.62
Construction of solid shapes through nets	1.40 (0.50)	4.52 (0.71)	223%	0.63
Distinguishing solid shapes with common features	1.76 (0.79)	4.31 (0.75)	146%	0.62
Calculating volume of solid shapes	1.32 (0.40)	3.86 (0.91)	192%	0.63

Comparisons of Final Performance of Students with SLD and Students with ADHD

No statistically significant post-intervention differences were found in the performance of students with SLD or ADHD in the control group. However, in the experimental group, students with SLD significantly outperformed their peers with ADHD in tasks involving correct management of solid shapes. Detailed numerical data are presented in Table V.

Table V. Comparative Presentation of Final Performance of Students with SLD and ADHD in Each Group

Category of educational need	Mean	Percent success (%)	p-value
Control group
SLD	20.18 (2.25)	81%	0.845
ADHD	20.26 (2.25)	81%
Experimental group
SLD	22.67 (1.60)	91%	0.000
ADHD	20.23 (1.13)	81%

Across both research groups, students with SLD achieved statistically higher scores on the test about geometric solid shapes than did students with ADHD (U = 456.000, z = −2.374, p = 0.011). Additionally, students with SLD in the experimental group significantly outperformed their counterparts in the control group when dealing with solid shape tasks (U = 52.500, z = −2.497, p = 0.013). As for students with ADHD, significant differences were observed between the groups, with the participants of the experimental group performing significantly better than their counterparts in the control group (U = 10.500, z = −3.003, p = 0.003).

In conclusion, the performance of both SLD and ADHD students in the experimental group significantly exceeded that of their counterparts in the control group. However, overall, there was no statistically significant difference in the performance of the participants between the experimental and control groups.

Discussion

Two mixed groups consisting of students with SLD or ADHD received instruction in recognizing, depicting, and understanding the properties of solid geometric shapes. The control group received instruction using the GICL model, which utilizes explicit instruction principles, clear goal-setting, multiple representations, and formative assessment. The experimental group was supported by a combination of GICL and visuospatial competence enhancements. A comparison of the mean pre- and post-intervention assessment scores for the control and experimental groups revealed that post-intervention scores were significantly higher. However, there was no significant difference between the post-intervention mean scores of the two groups. Furthermore, there were variations in the degree to which individual students from each disability category (SLD–ADHD) benefited from the interventions.

Effectiveness of Interventions

Both groups showed statistically significant improvements in solid shape tasks after receiving support through the study’s interventions. These findings align with meta-analytic evidence from interventions that applied explicit and direct instruction principles and practices to support students with SLD who struggled with geometric tasks and proved to be highly effective (Kozulin & Kazaz, 2017; Liuet al., 2021). Such findings are particularly significant for students with SLD or ADHD who struggle with geometric knowledge, since they suggest that through structured, explicit and goal-oriented instruction, these student groups may present considerable progress.

In explaining the present study’s findings regarding the positive impact of GICL, it can be hypothesized that the use of multiple representations is a key aspect of its effectiveness. Students with SLD or ADHD are known for the difficulties they face when they have to construct knowledge directly at the symbolic level, without previous experience with concrete and depictive material (e.g., Raymond, 2014). Hence, the opportunity offered to the participants of the present study to first process concrete and pictorial-depictive representations of solid shapes, and then transfer gradually to independent symbolic representations and abstract thinking may have allowed them to build a strong understanding of the specifics of each solid shape. The positive effects of multiple knowledge representations on math, especially geometric, performance of students with SLD or ADHD have also been established in the context of previous studies (Casset al., 2003; Papadam & Agaliotis, 2024, 2025).

Furthermore, instruction being implemented in the framework of the GICL model includes structured activities, close teacher supervision, requirements for mastery learning, and formative assessment. These methodological tools likely helped participants avoid learning gaps and ensured smooth progress. Similar findings have been reported by other studies that utilized explicit instruction principles to support struggling students in mathematics and other fields (e.g., Satsangiet al., 2020; Stevenset al., 2015).

Regarding the potential effect of visuospatial training on the geometric achievement of students with SLD or ADHD, the results align with previous research, suggesting that individual students may benefit from such training (e.g., Mammarellaet al., 2018; Zentallet al., 2013). However, the lack of significant differences in post-intervention scores between the control and experimental groups suggests that adding visuospatial enhancements to the GICL-based intervention does not significantly improve student performance at the group level. Although both the SLD and ADHD experimental groups outperformed the control groups, the overall difference did not reach statistical significance, likely because of the limited sample size. These results are to some extent in tune with findings from Agaliotis and Teli (2015, 2016) studies, where high-quality structured and explicit instruction of Arithmetic Combinations to students with SLD or Mild Intellectual Disability yielded, at the group level, results similar to those produced by the combination of explicit instruction with mnemonic interventions, although there were individual participants who received the combined intervention and presented noteworthy improvement. In explaining these results, it may be put forward that, at the group level, the improvements achieved through the GICL model alone were so high that it was difficult to surpass through the addition of visuospatial training (or mnemonic enhancement for that matter), although this addition may have helped a substantially small number of participants. Evidently, the fact that some students, particularly those from the SLD group, presented considerable improvement in geometric thinking when subjected to the combined intervention merits further exploration.

Overall, the aforementioned findings deserve consideration by researchers and practitioners, as they suggest that students with SLD or ADHD can be effectively supported through structured and Systematic Explicit Instruction, even without specialized cognitive support. Consequently, the inclusion of students from these two disability groups in general classrooms may be facilitated if such instruction is adopted in daily school practice.

Comparative Results of Students with SLD or ADHD

Comparisons of the post-intervention performance of students with SLD and students with ADHD, who were supported through the GICL model (control group), showed no significant difference. By contrast, in the experimental group, students with SLD significantly surpassed their peers with ADHD. Explanations for this difference may be found in the fact that successful completion of solid shape tasks necessitates challenging visuospatial activities (such as transitioning from two to three dimensions, mental rotation and visualization of unseen sides), and sustained attention (Kang & Zentall, 2011; Zhanget al., 2022). It could be hypothesized, then, that the visuospatial enhancement provided to the participants of the experimental group allowed students with SLD to overcome some of their difficulties and improve their performance. However, the implemented instruction benefited students with ADHD to a significantly lesser degree, because it did not include special measures to bypass the marked attentional difficulties usually exhibited by these students (e.g., Castro & Huamanchahua, 2021; Zentallet al., 2013).

Another explanation for the difference in the performance of students with SLD or ADHD in the experimental group may be found through the supposition that the provided visuospatial reinforcement may have been more compatible with the visuospatial needs of the SLD participants, which may have addressed their visuospatial inadequacies more effectively than the gains this intervention could offer to the ADHD subgroup.

Intra-categorical analyses of the performance of students with SLD and ADHD in thecontrol and the experimental groups revealed that students with SLD in the experimental group significantly outperformed their counterparts in the control group. This suggests that SLD students who received support through the combined intervention could cover their diverse cognitive and learning deficits better than their counterparts in the control group, who received support only through the GICL model. Similarly, significant post-intervention differences existed between students with ADHD in the experimental and control groups with the participants from the experimental group demonstrating significantly superior performance. This finding is consistent with prior research suggesting that visuospatial training may help students with ADHD improve their performance, despite the primary challenges they face with regard to attention span and duration (Auet al., 2015; Grevenet al., 2014; Parkeet al., 2020).

Conclusions

In summary, both instructional interventions affected students with SLD or ADHD to a considerable degree, although not in the same way and at the same achievement level. The GICL model seems to be an effective instructional tool for the support of students with Mild Disabilities, such as SLD or ADHD. The fact that this model has repeatedly produced positive results (e.g., Agaliotis & Teli, 2016; Kirpouiki & Agaliotis, 2024; Papadam & Agaliotis, 2025) is in line with research denoting the advantages of structured and Systematic Explicit Instruction (e.g., Bergstrom & Zhang, 2016; Liuet al., 2021). Evidently, the diverse needs of students with SLD or ADHD cannot be met to their full extent through the use of a single intervention. Visuospatial or other cognitive enhancements may play a significant role in the context of specialized support for SLD or ADHD students. Nonetheless, the finding that only through the use of evidence-based instruction models, like GICL, teachers may be in the position to effectively support students from the two aforementioned disability groups certainly deserves the attention of policymakers, researchers and practitioners.

Limitations of Research

The findings οf this study should be considered with caution because of certain limitations that need to be addressed in future research. One such limitation results from the fact that there was no statistically significant difference between the two study groups regarding the mean intelligence quotient, as inspection of the reports issued by the designated State Agencies that identified the participants’ disabilities showed that the IQ scores were very similar. However, the lack of statistical control may limit the generalizability of the findings. Another limitation was the small sample size, particularly for students with ADHD. Future research should include a larger number of participants. Finally, the study did not differentiate between subtypes of students with SLD or ADHD, as participants were identified by State Agencies that only specified the disability category of students.