2.1 Stage 1: Research Question

Following Peters et al. (2020), our research question is: How are functional impacts and impairments (Concept) of school-aged children (Context) at risk of or diagnosed with DLD or SLD (Population) defined and measured?

2.2 Stage 2: Study Identification

2.3 Stage 3: Study Selection

We conducted our search for the period between January 2013 and November 2023 across six databases (CINAHL, ERIC, Psychology & Behavioural Science Collection and Education Source), using the final set of keywords (see Appendix 1).

2.4 Stage 4: Data Extraction

During the data extraction stage, the following information were documented in a second Excel document, which was developed by the research team: general study details (author, title, year of publication, study location, methodology), specific study data (objective, population, measurement instruments used) and results (terminology or dimensions/indicators). In studies that included data on children with language and/or learning disorders alongside other groups (such as children with ADHD and ASD), only data related to the DLD and SLD groups were extracted. Data extraction was carried out by the first author. Instead of a reliability check, the first author has consulted the second or third author in case of uncertainty.

2.5 Stage 5A: Collating, Summarising and Reporting the Results

The included studies were systematically summarised in an Excel file, capturing key details such as study location, terminology related to functional impacts, and identified dimensions and indicators. The process began by listing terms related to functional impacts or impairments, along with their formal definitions or inferred meanings from the texts. A lexicographical analysis was conducted to explore usage frequency and semantic variations, helping identify common meanings, discrepancies and potential gaps in the literature.

A qualitative inductive approach (Elo and Kyngäs 2008) was then applied through an iterative process to identify dimension indicators from the literature. Initially, a deductive approach was attempted, aiming to categorise dimensions and indicators based on models like the ICF and HDM-DCP2. However, challenges arose due to the overlap and ambiguity of certain complex indicators, as noted by Kwok et al. (2023) in their critique of the ICF. For example, in the ICF model, social interactions are categorised either under participation (social engagement) or activity (competence in interactions), while the HDM-DCP2 model could categorise them under life habits, which are influenced by a combination of contextual factors and individual capabilities but are largely shaped by environmental factors. This difference in approach between the two models created confusion, as it was not always clear how to categorise social interactions in a way that reflected their complexity. Additionally, in the ICF model, language can be classified as a body function (physiological abilities), an activity (functional competence), or under participation (its influence on social engagement), whereas the HDM-DCP2 model views language as a skill shaped by both environmental and social factors, with a significant emphasis on the role of contextual influences. This variability further highlights the need for a more refined system that integrates individual, social and environmental influences, offering a clearer and more comprehensive framework for understanding functional impacts of neurodevelopmental disorders.

2.6 Stage 5B: Development of a New Classification System

To address the issues related to the classification of the indicators, the multidisciplinary research team—comprising two speech and language pathologists, one psychologist and one linguist—developed a new classification system, which refined existing categories to better reflect the multidimensional nature of functional impacts. This new classification system (see Table 2) integrates insights from Kwok et al. (2023) and Waine et al. (2023) to propose a more comprehensive framework for both clinical and research applications, capturing functional impacts across individual, social and environmental domains in neurodevelopmental disorders. To clarify the terminology used throughout this article, the term ‘functional consequences’ refers to an overarching concept that encompasses both ‘observed and perceived functional impacts’ —denoting, respectively, objectively measurable effects on functioning and individuals' subjective experiences of those effects. Furthermore, to address conceptual ambiguities and enhance the clarity of classification, the research team also refined and reorganised existing model categories from ICF and HDM-DCP2. Notably, Individual abilities were introduced as a distinct category, and Daily living and meaningful activities were used in place of the more general Activities and Participation, thereby highlighting the subjective significance of everyday tasks.

The last phase of the development process involved a deductive approach (Elo and Kyngäs 2008) used to organise the identified dimensions and indicators into five overarching categories: individual abilities, personal factors, daily and meaningful activities, relationships and environmental factors.

3.1 Selection of the Sources of Evidence

3.1.1 Included Studies

The literature search identified 1939 documents from the six databases, and 11 additional documents were identified from the reference lists of the selected articles. Of these, 97 full texts were read, leading to the inclusion of 53 documents for data extraction (see Appendix 2). A diagram outlining the study selection process is provided in Figure 1.

3.2 Assessment of Functional Impacts and Functional Impairment: Terminology and Dimensions

The key findings of our scoping review presented the main terminological concepts, dimensions, indicators and trends in the literature regarding the functional consequences of DLD and SLD in school-aged children.

4.1 Terminology: Disentangling Functional Impacts and Functional Impairment

The results of the lexicographic analysis revealed significant terminological variability and interchangeability across the 53 selected studies, along with notable inconsistencies, overlaps and gaps—largely attributable to underlying conceptual divergences. In this context, we deliberately chose not to retain the terms functional limitations and functional impairment when defining functional impacts or consequences. These terms are often rooted in a biomedical perspective focused on deficits and aligned with ableist frameworks (Bottema-Beutel et al. 2024; Timmons et al. 2024), which fail to sufficiently consider the personal and environmental factors that shape functional experiences in daily life. Moreover, as Waine et al. (2023) emphasise, the lack of clear definitions and detailed descriptions of the associated dimensions in the literature highlights the urgent need to reach consensus on a shared conceptual framework by providing clear definitions and listing the relevant indicators. This observation guided us in developing operational definitions that better align with contemporary recommendations.

Following this, an iterative lexicographical approach was employed to refine the initial definitions. This process involved multiple rounds of feedback from the research team, allowing for continuous revisions and improvements. Through this iterative process, the definitions were progressively refined, incorporating insights from ongoing discussions within the research team to ensure greater accuracy and clarity.

The final definitions include two interrelated concepts: ‘observed functional impacts’ (Essers et al. 2019; Feuering et al. 2014), which refer to the observable consequences of the disorder, and ‘perceived functional impacts’ (Essers et al. 2019; Feuering et al. 2014; Kaim et al. 2024; Martyr et al. 2019; Schütz et al. 2023; Serrano et al. 2022; Svensson et al. 2021), which pertain to the individual's subjective and personal experience. These concepts were refined through multiple rounds of discussion, ultimately reaching consensus. The distinction between observed and perceived functional impacts (Table 5) offers a more nuanced understanding of functional consequences.

The term ‘functional consequences’ (in French: conséquences fonctionnelles) serves as an overarching concept that encompasses both observed and perceived functional impacts. It refers to all consequences of a disorder on an individual's ability to perform activities, engage in social interactions and maintain a satisfactory quality of life. This definition explicitly acknowledges the dynamic and context-dependent nature of these effects, as well as the abilities and coping strategies individuals employ in various environments, leading to temporal and situational variability in disability. As emphasised by Catts and Petscher (2022), functional consequences fluctuate across contexts and evolve over time, influenced by the interplay between risk factors (e.g., a stressful environment) and protective factors (e.g., appropriate support). This concept highlights that the functional impacts of a disorder are not static but can change depending on both external and internal factors, which is crucial for understanding the full scope of an individual's experience and for planning appropriate interventions.

4.2 Development of a New Conceptual Model

A new conceptual model is needed to better capture the complexity of how DLD and SLD affect children's lives. The first step is selecting core terminology to guide its use. Current models, which focus on normative comparisons, overlook adaptive strategies, individual variations and contextual differences that shape functional experiences. Our analysis suggests that the dimensions and indicators related to functional impacts would benefit from a more structured organisation. Grouping conceptually similar elements would clarify their use and enhance comparability across studies.

To address this need, we drew on the clinical expertise of the first author—a speech and language therapist with 7 years of experience working with school-aged children—and integrated insights from complementary research disciplines. This clinical expertise, recognised as one of the four foundational pillars of the Evidence-Based Practice framework (alongside scientific evidence, patient preferences and contextual factors), played a vital role in bridging empirical and experiential knowledge. By serving as a form of ‘grey literature’, it offered a nuanced perspective grounded in real-world interactions with children and families (Fissel Brannick et al. 2022; Greenwell and Walsh 2021; Sackett et al. 1996; Souza and Cáceres-Assenço 2024). Drawing from this combined approach, the research item identified logical groupings based on conceptual similarities amongst the dimensions and indicators. This process led to the development of a classification system structured around four domains and organised into five overarching categories, each comprising a range of dimensions and their associated indicators.

To better capture the unique nature of an individual's skills and competencies, which are directly related to their capacity to perform activities and participate in social roles, ‘individual abilities’ is proposed as a distinct category from ‘personal factors’. By making this distinction, the classification system can more clearly address how individual capacities influence functional outcomes, independently from the broader personal factors (e.g., personal background, context, or environmental influences) that may shape those outcomes. Similarly, ‘Daily and meaningful activities’ is proposed as a replacement for ‘Activities’ and ‘Participation’ to emphasise the personal significance of tasks. This distinction clarifies the difference between functional tasks that individuals engage in routinely (e.g., self-care or home management) and the more socially driven roles or relationships (e.g., participation in group activities or social networks). These elements are judged to have a different impact on an individual's life, reflecting respectively functional independence and social interaction.

These new categories emphasised how the interactions between these elements collectively shape the overall functional impacts of DLD and SLD. The OPFI model encourages a holistic, multidimensional understanding of children's challenges and a more personalised approach to assessing their challenges and needs.

The OPFI model was designed as a practical tool to help clinicians and researchers adopt a shared language and gradually standardised practices for assessing the functional impacts of DLD and SLD in both clinical settings and research. This simplified and structured approach makes the assessment process more effective by considering the various dimensions that influence these functional impacts. The model emphasises that each child has a unique developmental profile, which includes notably cognitive, language, social, sensory and motor skills. These profiles influence how children engage in daily or meaningful activities and form fulfilling relationships with others. Both observed and perceived functional impacts are shaped by intra-individual variability (the child's profile) and environmental factors, which influence their social functioning and overall well-being.  The model highlights the importance of a supportive environment, such as family support, school accommodations and specialised services, which can reduce the perceived severity of the disorder and promote inclusion. It also emphasises the ‘compensatory or protective effect’ (Biotteau et al. 2017), where early interventions and inclusive environments foster brain plasticity and enhance abilities, improving quality of life.  Additionally, balancing internal demands (personal aspirations) and external demands (social, familial and professional pressures) is crucial in enabling children to thrive while maintaining their well-being. For example, a child with language difficulties who excels in sports may develop athletic skills and strengthen social relationships, positively impacting broader social interactions and expectations in different environments. These dynamics contribute to fostering autonomy, self-esteem and meaningful engagement.

4.3 Limitations

This scoping review has several limitations that should be considered when interpreting the results. The search period, from January 2013 to November 2023, may exclude key studies published before or after these dates. Publication bias may also influence the review, as studies with positive results are more likely to be published, potentially skewing the available evidence. The absence of interrater reliability across all stages of the review, as recommended by Pollock et al. (2023), may affect the consistency of findings due to differing subjective interpretations between reviewers. Efforts were made to include diverse perspectives, but the review focused on a limited number of languages and excluded sources not translatable via software, potentially introducing linguistic and cultural bias. The use of translation software, while practical, may not fully capture semantic accuracy and cultural nuances, impacting the result interpretation.

Regarding the new classification system, while it aimed to capture significant aspects of daily and meaningful activities as well as social relationships, it may not fully encompass the diverse experiences of children with DLD and SLD, particularly in terms of sex/gender differences, personal factors and environmental influences. For instance, children in complex social or family contexts may face additional barriers not addressed by traditional assessments (Singer et al. 2023). Moreover, sex/gender differences were not sufficiently explored, although academic and societal expectations may influence how boys, often considered at risk—particularly those from low socio-economic status backgrounds—exhibit strengths and weaknesses in language and social behaviour, along with their compensatory strategies (Mackie and Law 2014; McGregor 2020; Singer et al. 2023). A secondary analysis is being conducted to explore this issue in greater detail. Additionally, personal factors such as motivation, self-determination, awareness of the disorder and environmental changes like relocation or parental separation are often overlooked, yet they are crucial for understanding how children adapt to these challenges. These personal and environmental influences may interact with linguistic factors, especially in bilingual and multilingual children, who face unique challenges, such as limited access to tailored interventions. These limitations highlight the need for more comprehensive research to better capture the complex, multifaceted nature of the functional impacts of DLD and SLD.

4.4 Research Implications and Applications

The OPFI model offers a comprehensive and multidimensional framework for evaluating the functional impacts of language disorders by integrating both perceived and observed consequences. It promotes a shift from deficit-focused assessments toward a contextualised understanding of how language difficulties interact with personal factors, daily and meaningful activities, social relationships and environmental factors.

With its structured and operationalizable system of clearly defined indicators, the OPFI model should facilitate the harmonisation of findings and contribute to increasing the comparability across studies using it. If used to support the development of specialised tools and guide clinical reasoning, it might help to target and individualise interventions. Additional research is required to confirm that.

Future research could build on the OPFI model through longitudinal studies to track changes in functional impacts over time. Such studies would support the identification of impacts during key developmental transitions, as well as risk and protective factors, and long-term intervention outcomes. Including both perceived and observed impacts would enhance understanding of adaptation processes and help refine models of functional impairment in everyday contexts.

4.5 Clinical Implications

Documenting the functional consequences of DLD and SLD—such as their impact on daily and meaningful activities, social relationships and academic performance—is now an integral part of the diagnosis, and used to assess the severity of the disorder, and facilitating access to specialised services (Bishop et al. 2017; OOAQ 2018). The OPFI model offers a structured framework for evaluating observed and perceived impacts, providing a holistic perspective that informs clinical decision-making and intervention planning. This approach emphasises three key aspects: identifying and diagnosing the disorder, facilitating the access to services tailored to the child's needs, and developing individualised intervention strategies promoting inclusion.

4.6 Identification and Diagnosis

Standardised tests are widely used in diagnosing neurodevelopmental disorders; however, their utility is limited when used in isolation to assess these disorders' severity or functional impacts. While effective for identifying certain aspects of a child's cognitive and language abilities, these tests often do not fully capture the complexity of a child's profile (Lancaster and Camarata 2019). They are not sufficiently sensitive to the real-world implications of DLD and SLD (Calder et al. 2024). Furthermore, standardised tests do not reliably reflect a child's performance in naturalistic settings (McGregor et al. 2023) and show low sensitivity to changes over time, limiting their effectiveness for longitudinal monitoring (Bishop et al. 2016). The use of the OPFI framework provides a comprehensive framework integrating information from both standardised tests (i.e., assessments of language, cognition, or motor skills) and functional impacts (i.e., difficulties in daily and meaningful activities, school performance and social interactions). This highlights the importance of considering diverse contexts and subjective experiences, as proposed by Kwok et al. (2023), and involving children, parents and professionals in the evaluation process, as suggested by Bishop et al. (2016). While tools like FOCUS (Thomas-Stonell et al. 2010) are valuable for assessing communicative participation, they are not designed to diagnostically assess functional impacts (Waine et al. 2023).

This limitation underscores the need to develop multidimensional tools—grounded in the OPFI model—that extend beyond standardised test scores to capture the complex and context-dependent nature of functional consequences. By integrating functional documentation into assessments, clinicians can adopt a more child-centred approach, better respond to individual needs and ultimately enhance children's quality of life while supporting positive long-term outcomes (McGregor et al. 2020; Morgan et al. 2017; Westby and Washington 2017).

4.7 Service Delivery

Access to specialised services for children with neurodevelopmental disorders remains inequitable, often determined by criteria heavily reliant on standardised testing (Calder et al. 2023; Westby and Washington 2017). While such tests can be helpful in specific contexts, their reliance on rigid criteria can perpetuate disparities in service provision. Underserved children may miss critical interventions, while others may receive unnecessary services. Notably, boys are more frequently identified and offered services, which can disproportionately disadvantage girls (McGregor et al. 2020, 2023). This imbalance exacerbates the functional consequences of disorders: underserved children are left without the support they need, while over-served children may face irrelevant or misaligned interventions. Complementing standardised tests with systematic documentation of functional consequences, which can be facilitated by the use of the OPFI model,  might contribute to mitigating these inequities.

4.8 Speech-Therapy Intervention and Promoting Child's Inclusion

The functional consequences of DLD and SLD result from a dynamic interplay between intra-individual factors (e.g., cognitive abilities, emotional regulation and social skills) and inter-individual factors (e.g., family environment, school context and social interactions). These elements collectively influence developmental trajectories, often non-linear in nature, as illustrated in ADHD research by Sibley et al. (2022). Environmental variables alone can account for up to 20% of the variance in a child's functioning (Goldstein and Naglieri 2016, cited in Breault 2023), underscoring the need for tailored interventions rooted in each child's strengths, vulnerabilities and interests (Maillart et al. 2024).

A comprehensive functional assessment, aligned with the proposed OPFI model, should encompass both protective factors which foster resilience and promote participation (e.g., strong family support or inclusive classroom practices), modulating factors which may attenuate difficulties in specific activities or environments (e.g., access to visual supports or emotional regulation strategies) and aggravating factors which can intensify the perceived and observed impacts on the child's daily functioning (e.g., anxiety or exclusionary school settings). Interestingly, some comorbidities may provide compensatory benefits. ADHD co-occurring with DCD can sometimes enhance visuospatial skills, as observed by Biotteau et al. (2017). This suggests that comorbid conditions do not always worsen deficits and may, in some cases, offer functional advantages, as noted by Newcorn et al. (2001). Such observations invite clinicians to reconsider rigid deficit-based views and instead adopt a more nuanced understanding of functional diversity. By broadening our clinical lens to include both observed and perceived functional impacts across everyday contexts, we lay the groundwork for more equitable, context-sensitive and strength-based interventions.

While still in development, the OPFI model may already serve as a useful heuristic support to clinical reasoning and shared decision-making (see Appendix 3 for an illustrative case scenario). The next step is to examine the model's validity in supporting both the functional assessment of DLD and SLD as well as the co-construction of meaningful and individualised goals in clinical practice. Validation of its dimensions and indicators by an interdisciplinary expert committee will be essential to ensure their relevance, clarity and applicability across diverse settings.