Bibliometric Analysis of Research Trends in Spinal Cord Injury Rehabilitation: Mapping the Landscape of Scientific Publication

This section provides a comprehensive bibliometric analysis of social protection in the context of SCI and rehabilitation-related studies, based on publication overview, temporal, keyword, country, and citation analyses. In addition to conventional bibliometric methods, this study employs a co-citation network analysis to uncover underlying research paradigms and emerging trends within the field. This approach allows for a more nuanced understanding of the intellectual structure of SCI rehabilitation research.

The analysis of publication overviews reveals intriguing trends and developments in the field of SCI rehabilitation, WoS database, a total of 931 publications related to this topic were identified. This database demonstrates a positive growth rate, with an average of 73 publications per year. Moreover, the h-index of 60 highlights the significant impact of these publications, as they have received a substantial number of citations. In the Scopus database, there were 446 publications associated with SCI rehabilitation. Although the annual growth rate shows a slight decline of -2.2%, it is noteworthy that the h-index is 31, suggesting a considerable impact of these publications within the field. While the average number of publications per year is 12, the variation in publication frequency indicates fluctuations in research activity across different years (Figure 2).

Figure 2:
Publication overview from 1946 to 2023.

Figure 3 shows the top countries that contribute to the development of papers related to SCI in rehabilitation. The United States (US) emerges as the leader in terms of the number of publications, with 403 articles. This reflects a consistent and significant commitment to SCI rehabilitation research. Despite a slight decline in the annual growth rate, the country maintains an average of 20.6 publications per year, which is indicative of stable research output. Canada follows closely behind, with 160 publications.

Figure 3:
Top countries related to SCI in rehabilitation.

Despite a similar decline in the annual growth rate, the country exhibits a higher average of 40.6 publications per year. Australia demonstrates a commendable involvement in SCI rehabilitation research, with 97 publications. While the annual growth rate remains steady, the country maintains an average of 38.1 publications per year. The Netherlands has produced 96 publications, displaying a consistent engagement in SCI rehabilitation research. Despite a relatively lower annual growth rate, the country maintains an average of 18.8 publications per year. Switzerland, with 79 publications, stands out for its noteworthy contributions to SCI rehabilitation research. Despite a minimal annual growth rate, the country maintains an impressive average of 49.4 publications per year.

The University of Toronto leads the list with 54 publications, indicating its strong commitment to SCI rehabilitation research (Figure 4). The institution has shown a positive average growth rate and a notable productivity of 6.8 publications per year. The University of Groningen follows closely behind with 39 publications. Despite a slightly negative growth rate, the institution maintains a significant productivity of 2.8 publications per year.

Figure 4:
Active institutions related to SCI in rehabilitation.

The University of British Columbia demonstrates a strong involvement in SCI rehabilitation research with 38 publications. Though the growth rate is slightly negative, the institution maintains a notable productivity of 2.2 publications per year. The University Health Network, comprising a network of hospitals and research institutes, has produced 37 publications.

The institution exhibits a positive growth rate and a remarkable productivity of 5.2 publications per year. The Swiss Paraplegic Research and Swiss Paraplegic Center, both affiliated with the Swiss Paraplegic Foundation, contribute significantly to SCI rehabilitation research. They have produced 34 and 31 publications, respectively. Both institutions show positive growth rates and remarkable productivity of 4.6 and 4.8 publications per year.

Figure 5 shows the most popular and commonly used subject areas in the publications related to SCI in rehabilitation. In the field of Neurosciences and neurology, which ranks first in terms of total publications with 378 articles, there is active research in SCI rehabilitation. The Average Growth Rate (AGR) of 2.6 publications per year indicates a steady increase in research output. The high h-index of 47 reflects the impact and citation count of the publications, suggesting their influence within the field. Sport Sciences, with 166 publications, focuses on the intersection of sports and SCI rehabilitation.

Figure 5:
Top Subject Areas.

Although the AGR is relatively low at 0.4, indicating a slower growth rate, the field demonstrates a high productivity per day (PDLY) value of 19.3. This suggests a concentrated effort in publishing research related to sports and SCI rehabilitation. The h-index of 39 indicates the impact and influence of these publications within the sports science community. General and Internal Medicine, with 58 publications, plays a significant role in SCI rehabilitation research.

The AGR of 0.8 and PDLY of 50 indicate a consistent publication output and a substantial contribution to the medical field. The h-index of 13 suggests a moderate impact of these publications, reflecting their citation count and influence within the medical community. The field of Engineering, with 49 publications, demonstrates a relatively high PDLY of 49, indicating focused research efforts in this area. However, the AGR of -0.6 suggests a slight decline in publication output over time. The h-index of 13 reflects the impact and citation count of these publications within the engineering community. Orthopaedics, with 49 publications, focuses on the orthopaedics aspects of SCI rehabilitation. The AGR of 0.6 indicates a moderate growth rate in research output.

The h-index of 19 suggests a notable impact and citation count for these publications within the field of orthopaedics. Public, Environmental and Occupational Health, with 20 publications, highlights the importance of considering public health aspects in SCI rehabilitation. The AGR of 0 and PDLY of 25 indicate a consistent publication rate. The h-index of 9 reflects the impact and influence of these publications in the field of public health. Health Care Sciences and Services encompass 19 publications related to SCI rehabilitation. The AGR of 0 and high PDLY of 68.4 indicate a concentrated effort in publishing.

The h-index of 6 suggests a moderate impact of these publications within the field of healthcare sciences and services. In the field of Robotics, with 19 publications, technological advancements in SCI rehabilitation are explored. The AGR of -0.4 suggests a slight decline in publication output over time. The h-index of 6 reflects the impact and citation count of these publications within the robotics community. Nursing, with 18 publications, contributes to SCI rehabilitation research from a nursing perspective.

The AGR of -0.2 indicates a relatively stable publication output. The h-index of 8 suggests a moderate impact and citation count for these publications within the nursing field. Finally, Surgery focuses on surgical interventions and techniques in SCI rehabilitation, with 16 publications. Although the AGR is 0, the field demonstrates a high PDLY of 50, indicating concentrated research efforts. The h-index of 7 reflects the impact and influence of these publications within the surgical community.

Thematic analysis of the 3001 keywords (Figures 6a and 6b) used in indexed articles related to rehabilitation and SCI reveals several key themes and topics. VOS viewer’s clustering analysis has identified five distinct clusters, each representing a significant research area within the field.

Figure 6(a):
Visualization of all keywords.

Figure 6(b):
Overlays of all keywords.

Recovery and Function: This cluster emphasizes the importance of functional recovery and rehabilitation interventions. Keywords like “recovery,” “locomotion,” “walking,” “functional recovery,” “spasticity,” “motor,” and “body-weight support” highlight the focus on improving physical function and mobility. This cluster is strongly associated with the concept of rehabilitation and its impact on regaining lost abilities.

Social and Psychological Aspects: This cluster focuses on the broader social and psychological aspects of SCI rehabilitation. Keywords like “people,” “quality-of-life,” “community,” “social support,” “satisfaction,” “employment,” “adults,” “time,” “work,” and “vocational rehabilitation” indicate the importance of addressing the social, psychological, and occupational needs of individuals with SCI. This cluster suggests a growing recognition of the holistic nature of rehabilitation, extending beyond purely physical aspects.

Neurological and Medical Complications: This cluster centers on the neurological and medical complications associated with SCI. Keywords like “spinal cord injuries,” “paraplegia,” “tetraplegia,” “outcomes,” “medical complications,” “length-of-stay,” “international standards,” “illness,” “severity,” “physical capacity,” and “occupational therapy” reflect the focus on understanding the underlying neurological mechanisms and addressing the specific medical challenges faced by individuals with SCI.

Assessment and Measurement: This cluster focuses on the assessment and measurement of outcomes in SCI rehabilitation. Keywords like “lesions,” “diagnosis,” “scale,” “validity,” “follow-up,” “efficacy,” “clinical-trials,” and “outcome measures” highlight the importance of standardized assessments and reliable measures for evaluating the effectiveness of interventions.

Psychological Well-being: This cluster addresses the psychological well-being of individuals with SCI. Keywords like “depression,” “anxiety,” “hospital anxiety,” “trauma,” and “barriers” indicate the significance of addressing mental health challenges and understanding the psychological impact of SCI. This cluster underscores the need for a multidisciplinary approach to rehabilitation, considering not just physical but also emotional and mental well-being.

This analysis of author keywords, guided by thematic clustering, provides a valuable overview of the diverse research areas within SCI rehabilitation. It highlights the ongoing focus on functional recovery, the growing recognition of social and psychological factors, the importance of addressing neurological and medical complications, the need for robust assessment and measurement tools, and the increasing attention to mental health and well-being.

The Table 2 provides information on the most cited articles in the field of rehabilitation, particularly in the field of study by Ma et al.,^[33] on the incidence, prevalence, costs, and impact of various common conditions requiring rehabilitation in the US.

Authors	Title	Citations
Ma VY, Chan L, Carruthers KJ.[33]	Incidence, Prevalence, Costs, and Impact on Disability of Common Conditions Requiring Rehabilitation in the United States: Stroke, Spinal Cord Injury, Traumatic Brain Injury, Multiple Sclerosis, Osteoarthritis, Rheumatoid Arthritis, Limb Loss, and Back Pain.	575
Giangregorio L, McCartney N.[34]	Bone loss and muscle atrophy in spinal cord injury: epidemiology, fracture prediction, and rehabilitation strategies.	232
Nas K, Yazmalar L, Şah V, Aydın A, Öneş K.[35]	Rehabilitation of spinal cord injuries.	208
Behrman AL, Bowden MG, Nair PM.[42]	Neuroplasticity after spinal cord injury and training: An emerging paradigm shift in rehabilitation and walking recovery.	201
Chen D, Apple DF Jr, Hudson LM, Bode R.[43]	Medical complications during acute rehabilitation following spinal cord injury – Current experience of the model systems.	182
Stiens SA, Bergman SB, Goetz LL.[44]	Neurogenic bowel dysfunction after spinal cord injury: Clinical evaluation and rehabilitative management.	176
Lima C, Escada P, Pratas-Vital J, et al.,[45]	Olfactory Mucosal Autografts and Rehabilitation for Chronic Traumatic Spinal Cord Injury.	174
Harkema SJ.[46]	Neural plasticity after human spinal cord injury: Application of locomotor training to the rehabilitation of walking.	170
Dobkin B, Barbeau H, Deforge D, et al.,[47]	The evolution of walking-related outcomes over the first 12 weeks of rehabilitation for incomplete traumatic spinal cord injury: The multicentre randomized Spinal Cord Injury Locomotor Trial.	166

Table 2:
The most cited papers related to SCI in rehabilitation (minimum of 150 citations).

This comprehensive study covers conditions such as stroke, SCI, traumatic brain injury, multiple sclerosis, osteoarthritis, rheumatoid arthritis, limb loss, and back pain. It has garnered 575 citations, highlighting its relevance in understanding the epidemiology and impact of these conditions on disability and healthcare costs.

The study by Giangregorio and McCartney^[34] on “Bone loss and muscle atrophy in spinal cord injury” has been cited 232 times. Additionally, Nas et al.,^[35] contributed to the field of SCI rehabilitation with their article “Rehabilitation of spinal cord injuries,” which has garnered 208 citations. The authors explore various rehabilitation approaches and techniques for individuals with spinal cord injuries, emphasizing the importance of comprehensive rehabilitation programs.

This study provides a comprehensive bibliometric analysis of research in SCI rehabilitation, addressing key research questions related to the evolution of publication volume, leading contributors, emerging themes, and impactful studies. The findings offer valuable insights into the current state and future direction of the field.

A remarkable development trajectory over the last three decades, especially in the most cited paper is revealed by the bibliometric study of research on SCI rehabilitation. The growing number of research published each year, particularly in the WoS database, which averaged 73 publications annually, is indicative of this expansion. This increasing trend demonstrates the increased interest in addressing the complicated demands of SCI patients as well as the growing acknowledgement of SCI rehabilitation as an important field of study.

Comparing these findings with previous studies offers valuable insights. Liu et al., conducted a bibliometric analysis from 1997 to 2016, noting a rise in publication rates and emphasizing the need for higher-quality research.^[28] Their analysis emphasised the need for better research quality while identifying new research areas and international collaboration. This is in line with the current data, which also demonstrates a notable expansion and variety in the emphasis of publications, but it also points to the ongoing need for top-notch research and a more global viewpoint.

Kiraz and Demir provided an analysis from 1980 to 2018, highlighting trends and advancements in SCI research.^[29] Their analysis revealed a rise in research production but also pointed up limitations, including the omission of grey literature and non-English publications. Although the current analysis provides a more recent and comprehensive assessment of the diversification in research focus, including multidisciplinary approaches, it is consistent with their findings on increased research output.

Li et al., analysed articles from 1999 to 2019, identifying leading countries and institutions and providing a knowledge base for future research.^[30] Their findings, particularly regarding significant contributions from institutions like Harvard and the University of Toronto, are mirrored in the current study, which also highlights these institutions’ roles in advancing SCI research.

Guo et al., focused on stem cell therapy for SCI, noting trends and limitations in clinical trials and long-term follow-up data.^[36] The current analysis goes beyond their study’s specific focus on stem cell research to include multidisciplinary approaches and emerging themes, in addition to broader trends in SCI recovery.

Phadke et al., examined gait rehabilitation research, highlighting the USA, Canada, and Switzerland as leading contributors, and noting a shift towards interdisciplinary and technology-driven approaches.^[38] The current analysis, which also reflects an increasing emphasis on multidisciplinary techniques and technological integration in SCI rehabilitation, is enhanced by the study’s focus on gait rehabilitation

According to the current data, there has been a notable increase in research on SCI rehabilitation over the previous 20 years, which is indicative of a greater understanding of the intricate difficulties that people with SCI confront. In addition to exhibiting a commitment to improving rehabilitation results, this expansion has resulted in a notable diversification of priority areas. These days, research covers a broad range of subjects, including patient-centred care, psychosocial rehabilitation, and technological innovations including virtual reality, robotic-assisted therapy, and telehealth. These developments are essential for satisfying the rising need for efficient rehabilitation services, especially in environments with limited resources.

However, the report also highlights the field’s ongoing geographical disparities and quality gaps. Despite a rise in research production, there are notable regional differences in study quality. The literature is dominated by nations with established research infrastructures, placing others at a disadvantage because of a lack of resources and competent employees.^[37,29]

This discrepancy calls into question the findings’ generalisation as well as the equitable distribution of funds required for successful SCI recovery. Developing comprehensive treatment models that address the complex requirements of people with SCI requires a strong emphasis on interdisciplinary teamwork.^[38] To guarantee that improvements benefit everyone, regardless of their situation or location, stakeholders must provide priority to these initiatives.

According to a recent bibliometric review of research on SCI rehabilitation, the United States is the world leader in this area, with Canada, Australia, and other European nations including the Netherlands and Switzerland also making substantial contributions. Key contributors that have demonstrated their significant output and impact in SCI rehabilitation research include the University of Toronto, the University of Groningen, and the University of British Columbia. The focus on fields like general and internal medicine, sports sciences, and neurosciences demonstrates a multidisciplinary approach that takes into account both the psychological and physical elements of SCI.

Comparing these findings with previous studies reveals both continuities and developments in SCI research trends. Liu et al., identified increasing publication rates and emerging research topics in SCI rehabilitation but noted the need for higher quality research.^[28] Their study concentrated more on global trends and the need to raise the standard of research rather than exploring deeper into regional contributions. The current analysis confirms the growth noted by Liu et al., but provides a clearer picture of leading countries and institutions, illustrating a more detailed geographical and institutional landscape.^[28]

Kiraz and Demir analysed SCI research from 1980 to 2018, identifying trends and advancements while noting limitations such as the exclusion of non-English publications and grey literature.^[29] Their findings align with the current study’s observation of increasing publication volume but do not fully capture the present-day focus on multidisciplinary approaches and emerging trends in SCI rehabilitation.

Li et al., examined global SCI research from 1999 to 2019, highlighting leading countries, institutions, and significant authors.^[30] Their study corroborates the current analysis by recognizing the prominent roles of institutions like Harvard and the University of Toronto but may not fully reflect the recent shift towards broader multidisciplinary research areas as observed in the current study.

Therefore, by describing the evolving landscape of SCI rehabilitation research, highlighting top nations and institutions, and indicating a shift towards a multidisciplinary approach, the current analysis validates and expands on earlier studies.^[37,40] However, a continuous disparity in contributions from low- and middle-income countries is revealed by the dominance of higher-income nations like the US, Canada, and portions of Europe.^[29,39] This could restrict the findings’ worldwide applicability and usefulness.

A more equal research environment is crucial, even though developments in sports sciences and neuroscience are encouraging. In order to meet the full range of SCI rehabilitation demands and guarantee research quality, inclusivity, and relevance across various populations and resource settings, future studies must promote collaboration across diverse areas.

In this study, five distinct research themes in SCI rehabilitation were identified through a thematic analysis of author keywords. These clusters offer a comprehensive view of current research areas, yet reveal certain limitations in addressing broader issues in SCI rehabilitation. The first cluster, “Recovery and Function,” emphasizes functional rehabilitation, with key terms like “walking,” “spasticity,” and “motor recovery” underscoring the centrality of physical improvement. The second cluster, “Social and Psychological Aspects,” highlights growing recognition of SCI’s broader social and psychological impacts, aligning with past studies that stress comprehensive recovery approaches.

The third cluster, “Neurological and Medical Complications,” focuses on medical challenges and underlying neurological factors. This aligns with earlier research identifying the need to address SCI-related medical complexities in rehabilitation. The fourth cluster, “Assessment and Measurement,” underscores standardized outcome measures, supporting prior studies on the importance of consistent evaluation tools. Finally, the “Psychological Well-being” cluster reflects an increased focus on mental health.

The thematic clusters in SCI rehabilitation research provide essential insights into the field’s focus areas. However, certain gaps highlight limitations in addressing the full scope of post-injury needs. Notably, there is a lack of research on the economic impacts and community reintegration of individuals with SCI. This gap restricts the field from fully exploring long-term quality of life improvements beyond physical recovery, as studies predominantly emphasize clinical assessment and immediate rehabilitation outcomes.^[2,41]

Although outcome measurement and assessment are critical for tracking recovery, this focus on evaluation over practical, real-world solutions suggests an opportunity to broaden research efforts. Current rehabilitation studies heavily prioritize assessment tools and techniques without consistently translating findings into accessible, impactful interventions that benefit diverse populations directly.^[16] Bridging this gap could advance SCI rehabilitation by addressing economic factors, resource accessibility, and integration back into society.

Expanding these clusters to include community and economic considerations would support a more holistic approach, aligning with recent studies that emphasize long-term reintegration and resource accessibility for sustained rehabilitation outcomes. Such an inclusive model could significantly enhance the quality of life for SCI individuals, creating a foundation for ongoing support and integration beyond initial rehabilitation.

The analysis of highly cited publications in SCI rehabilitation research reveals several influential studies that have notably shaped the field. The studies by Ma et al., and Giangregorio et al., have garnered significant citations for their comprehensive exploration of SCI epidemiology and rehabilitation strategies.^[33,34] These publications have contributed essential knowledge and frameworks that have guided subsequent research and clinical practice in SCI rehabilitation.

Comparing these findings with previous studies offers valuable context. Liu et al., highlighted the increasing publication rates and emerging hot topics in SCI rehabilitation but did not specifically focus on highly cited individual studies.^[28] Their analysis was more concerned with global trends and the need for higher quality research. In contrast, the current analysis provides a detailed look at how specific influential publications have shaped the field, offering a more granular understanding of their impact.

Kiraz and Demir also examined trends in SCI research but focused on broader publication trends from 1980 to 2018.^[29] Their study did not delve deeply into citation counts of individual papers but provided a comprehensive overview of research output and collaborations. The current analysis complements their findings by highlighting the role of highly cited publications in shaping research directions.

Li et al., identified significant contributors and influential institutions but did not emphasize specific highly cited studies.^[30] Their work is aligned with the current findings in recognizing the contributions of leading institutions and authors, yet the current analysis adds depth by detailing the impact of specific influential papers.

The current analysis of highly cited articles gives a concentrated evaluation of important works that have significantly influenced the field of SCI rehabilitation, although earlier studies have offered insightful information about trends, institutions, and research output.^[37,40] Though these seminal studies offer crucial foundations and benchmarks, the focus on widely referenced works may obscure new voices and creative research from less well-known sources.^[29] It’s also possible to run the risk of putting popularity ahead of originality or study quality when using citation counts as the primary indicator of influence.

Effectively advancing SCI rehabilitation requires striking a compromise between incorporating more recent research that examines under-represented viewpoints and well-established, widely referenced studies, especially in areas like community reintegration and customised therapy techniques. Promoting a wider range of studies may yield more comprehensive, equitable progress in SCI rehabilitation practices.

The findings from this bibliometric analysis offer several significant implications for the field of SCI rehabilitation research. Firstly, the analysis underscores the growing body of literature in this domain, reflecting an increasing global commitment to advancing knowledge and practice in SCI rehabilitation. However, the uneven distribution of research across different regions points to geographical disparities in research efforts. The dominance of high-income countries, particularly the United States and Canada, suggests that research leadership is concentrated in regions with more substantial resources and research infrastructures. This concentration has implications for the generalizability of research findings, as the specific needs and challenges faced by SCI patients in low- and middle-income countries may not be adequately addressed.

Moreover, the identification of leading institutions, such as the University of Toronto and the University of Groningen, highlights centers of excellence that drive innovation in SCI rehabilitation. These institutions not only produce a significant volume of research but also shape the direction of the field through their contributions. The clustering of frequently used keywords reveals emerging themes and trends in SCI rehabilitation research. The emphasis on recovery and function, social and psychological aspects, and neurological complications indicates a multidisciplinary approach to SCI rehabilitation, reflecting the complexity of the condition and the need for comprehensive care strategies.

Finally, the analysis of highly cited publications demonstrates the critical impact of certain studies on the field. These influential works have set the foundation for current practices and future research directions. However, the reliance on citation counts as a measure of impact may overlook newer, innovative research that has not yet had the time to accumulate citations.

The findings from the bibliometric analysis of SCI rehabilitation research reveal critical insights that can guide future research efforts. To address the geographical disparities in research output, there is a pressing need for increased international collaboration, particularly involving researchers from low- and middle-income countries. By fostering global partnerships, researchers can pool resources, share expertise, and ensure that the challenges of SCI rehabilitation are addressed comprehensively.^[35] Funding agencies should prioritize support for collaborative research initiatives that bridge the gap between regions with varying levels of research infrastructure, thereby enhancing the inclusivity and applicability of SCI rehabilitation research on a global scale.

The complexity of SCI rehabilitation underscores the importance of a multidisciplinary approach that integrates perspectives from neurology, psychology, engineering, and social sciences.^[36] The identified research clusters emphasize the value of such integration in developing holistic rehabilitation strategies that address both the physical and psychological needs of SCI patients. Future research should continue to encourage collaboration across disciplines, bringing together scientists, clinicians, and engineers to develop innovative interventions that advance comprehensive rehabilitation programs.

Innovation in SCI rehabilitation research must be a priority.^[40] While well-established research has significantly impacted the field, emerging themes and innovative approaches should be actively supported. Funding agencies and academic institutions should prioritize cutting-edge research that explores new frontiers in SCI rehabilitation, such as the use of robotics, personalized medicine, and advanced neurorehabilitation techniques.^[41] Additionally, the analysis identifies gaps in current research, particularly regarding long-term outcomes of rehabilitation interventions and the integration of technology. Addressing these gaps is crucial to building a more comprehensive evidence base for SCI rehabilitation. Improving the accessibility of research findings to practitioners and policymakers is essential for translating research into practice, ultimately leading to better patient outcomes in SCI rehabilitation.

While this study offers a comprehensive overview of research trends in SCI rehabilitation, it is important to acknowledge certain limitations. The reliance on bibliometric data from specific databases may have led to the exclusion of relevant publications not indexed in these sources. Additionally, the analysis does not account for the quality of publications, which could vary significantly across different studies. Future research could address these limitations by incorporating a more diverse range of sources and applying qualitative assessments of publication impact.

In conclusion, this bibliometric analysis highlights the dynamic and evolving nature of SCI rehabilitation research. The growing volume of publications, the contributions from leading countries and institutions, and the emergence of new research themes all point to a field that is expanding in scope and impact. However, the analysis also reveals gaps in certain research areas and geographical disparities, suggesting opportunities for further exploration and collaboration. Future research should continue to build on these findings, addressing the identified gaps and exploring new frontiers in SCI rehabilitation to enhance the quality of life for individuals with SCI.

We thank to our ‘Geran Galakan Penyelidik Muda’ (GGPM 2023-071) and ‘Early Career Research Award’ (NN-2024-023), Universiti Kebangsaan Malaysia (UKM) as well as colleagues from the Physiotherapy Department and Centre for Rehabilitation and Special Needs Study, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, who provided insight, advice, and expertise that hugely assisted in this study.