A Novel Tool to Assess Basic Activities of Daily Living in Spanish Preschoolers

Background: Basic activities of daily living (BADLs) are those related to self-care. Their performance depends on the development of sensorimotor and cognitive skills, as well as social and environmental aspects. A good performance in BADLs is required for independence and social participation, so they play an important role in early education and early care. We aim to create a tool for BADLs assessment for Spanish preschoolers. Methods: The tool was administered to 303 participants (48.5% boys and 51.5% girls) between three and six years of age. Analyses to find out the factorial structure and internal consistency was carried out. Results: The instrument was composed of 84 items in four scales (eating, personal hygiene, dressing, and daily functioning) with nine factors (oral sensitivity, good manners, manual dexterity, brushing teeth, toilet management, hygiene and grooming, dressing, higher-order and core executive function). Reliability values were from acceptable to preferred (0.74–0.94). Conclusions: The instrument could be useful and shows preliminary good indicators in construct validity and reliability.


Activities of Daily Living Conceptualization and Development
Activities of daily living (ADLs) refers to a group of tasks that every person carries out to be independent. Concretely, basic activities of daily living (BADLs) refer to the ones oriented toward taking care of one's own body including mobility, feeding, personal hygiene and dressing. Instrumental activities of daily living (IADLs) are activities to support daily life in home and community, often more complex than BADLs, including home management, taking care of others or community mobility [1,2]. BADLs are gradually acquired during childhood, and through practice they become almost automatic, while IADLs are developed through education and practice, with a greater influence on the individual's life roles [3]. The inability to accomplish ADLs may lead to unsafe conditions, lower participation, caregiver overload and poorer quality of life [4].
ADLs development is related to motor, physical, cognitive and emotional areas [5], but also to practical experience and contextual factors. Thus, their outcomes result from the dynamic intersection of the individual, task/activity and context/environment characteristics [6].
Preschool age is a period of huge growth in ADLs development. Initially, infants are completely dependent on their caregivers in terms of care, even talking of co-occupations. Around 2-4 years, they begin to manage their cutlery, as well as simple clothes. Then, about 5-6 years, most typically developing children perform the most essential tasks/activities However, children with neurodevelopmental disorders [11] are often unable to reach these milestones, showing significant challenges, poorer outcomes, delays, and impairments compared to their typical development peers [12][13][14][15].

Underlying Factors in Activities of Daily Living
Several factors are important for proper ADLs performance. On the one hand, brain maturation-associated internal factors, especially to the prefrontal lobe, include processes such as perception, memory, or executive function (EF) [16,17]. EF are a set of cognitive skills necessary for goal-oriented behavior. There is some agreement on considering inhibition and interference control, working memory, and cognitive flexibility as core sub-processes [18][19][20]. Inhibition means being able to control one's attention, thoughts, emotions, or behaviour, suppressing other stimuli. Working memory let us to briefly maintain information while performing other operations. Cognitive flexibility refers to being able to switch between thoughts or actions depending on the demands of the context [21][22][23]. From core EFs, higher-order EFs are built, including planning (choosing steps to reach a goal), reasoning, and problem-solving [22,24]. Regarding its development, a first phase happens during the first three years of life, where basic skills emerge, and a second one between the third and the fifth years, when different sub-processes begin to coordinate achieving adaptive goals [20,25]. Thus, EF is essential for all ADLs and to succeed in any daily task [26][27][28][29][30].
On the other hand, social and contextual factors are also essentials for ADLs development, including family and school. During childhood, caregivers must provide opportunities for children to practice ADLs in their communities, encouraging their social participation. This repeated practice promotes the establishment of occupational roles and routines, transmitting cultural values to the child [3,31]. Parenting styles are also relevant, considering that democratic styles are associated with greater independence, while overprotection, overcontrol, persistence in performance, or excessive permissiveness negatively affect children's mental health and sense of competence [32].

Activities of Daily Living in Early Education and Early Intervention Services
In addition to home and community settings, there are two other contexts in which monitoring ADLs development is essential: at school and, when signs of dysfunction are detected in early intervention services. Regarding school, in Spain, preschool education is Children 2021, 8,496 3 of 18 divided into two stages: 0-3 years, and 3-6 years. Every stage has its own goals, contents, and evaluation criteria. Both stages are structured in three main areas: environment knowledge, languages, and self-knowledge and functional independence [33,34]. Table 2 shows some of the closest contents related to ADLs, including aspects related to EF required for successful performance. Table 2. Activities of daily living related contents in the early education Spanish curriculum [33]. Monitoring children's development is critical so that appropriate actions can be undertaken as early as possible; either through educational adjustments or referring to early care services [35,36]. These services aim to respond to temporary or permanent needs presented by children with developmental disorders or at risk [37], and in planning and carrying out interdisciplinary interventions.

Preschool-First
In early education, ADLs performance is assessed by teachers, mainly through students' behaviours observation. Families play an unquestionable role in children's education [38], so teachers must obtain information about ADLs performance of their students in natural environments through their caregivers [34]. Therefore, observational tools or questionnaires completed by caregivers seem to be an interesting tool [39]. They can also be useful for early care therapists since, although therapists commonly work in clinical settings, they also need to collect information about children's performance in their natural environments [10,[40][41][42][43].

Assessment of Activities of Daily Living in Preschoolers
Several observational tools can be considered to assess ADLs in children from three to six years: The Vineland Adaptive Behavior Scales [44,45], The Adaptive Behavior Assessment System [46,47], The Checklist of Adaptive Living Skills [48], The Inventory for Client and Agency Planning [49], The Pediatric Evaluation of Disability Inventory-Computer Adaptive Test [50], The Battelle Developmental Inventory [51], or the Merrill-Palmer-Revised Scales of Development [52]. However, these instruments present limitations to be applied during the ADL's evaluation process: (1) some of them are not focused on ADLs construct, but on the concept of adaptive behaviour. It can be problematic as adaptive behaviour is not synonymous with ADL, including different domains and giving more or less weight to ADLs according to authors' points of view [53]; (2) some of them do not cover the full range of BADLs; while (3) others are translated into Spanish but, to our best knowledge, without performing a cultural adaptation process.

Aim
This study aims to present the psychometric properties (construct validity and reliability) of a tool to measure BADLs performance in typically developing Spanish preschoolers aged 3-6 years. We hope this tool will (1) help to characterize the BADLs performance of typically developing children serving as a screening instrument and (2) will be useful to detect deviations from normality in the BADLs development of children with neurodevelopmental disorder diagnoses, helping professionals in early education and early care services.

Study Design
Participants were recruited through schools and social events in Extremadura (Spain). Furthermore, a convenience clinical sample of 11 participants with autism spectrum disorders (ASD) aged 3-6 years was included to analyze the classification ability of the questionnaire.

Participants
Three-hundred and three preschoolers with typical development, aged from 3 to 6 years (3 years = 13.2%; 4 years = 26.1%; 5 years = 32%; and 6 years = 28.7%), participated in the study. The sample was composed of 147 boys (48.5%) and 157 girls (51.5%). All participants provided written informed consent before starting data collection. To be included in the study, participants need to meet the following eligibility criteria: (1) age between 3 and 6 years, (2) attend to ordinary schools, (3) no present disorders according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [11], and (4) provide informed consent.

Creation of the Basic Activities of Daily Living Assessment in Preschoolers
A group of five experts from the clinical field (occupational therapists, and specialists in developmental psychology and neurodevelopmental disorders), selected for their experience in childcare (clinical and educational) and development of psychological tests, were recruited. Initially, an exhaustive review of the available instruments assessing children development, sensory integration, cognitive assessments, and ADLs was carried out. A rational criterion was followed for the selection of behaviours represented in most of the instruments (achieved or in process). The selected items were classified, developing a pool of 250 items. An operational proposal for the different dimensions was submitted to the experts' judgement. Thus, the experimental version consisted of 113 items. Subsequently, a pilot study was carried out with the participation of 15 families who were asked to answer the questionnaire, assessing the clarity of each item and allowing them to make proposals about wording. They were also informed about the time required to complete the test. Finally, the relationships between the proposed dimensions were explored and the items that did not fit in the model were removed. Thus, the final version of the tool includes 84 items. Figure 1 shows the steps followed for developing the instrument.

Description of the Basic Activities of Daily Living Assessment in Preschoolers Tool
The Basic Activities of Daily Living Evaluation in Preschoolers (BADL-P), a novel questionnaire created for Spanish preschoolers during this study, was used. The BADL-P included 84 items, distributed in 4 scales with 9 factors that provide a theoretical model to support the instrument. Eating, personal hygiene and dressing are BADLs themselves, as explained, while the daily functioning scale includes information about cognitive skills critical for good BADLs performance ( Figure 2). Most of the items are written in positive form, and those in negative were recoded. This instrument must be completed by interviewing main caregivers. Response options for every item are always, sometimes, never, or not known/no opportunity. Therapists or educators must obtain evidence that caregivers' answers are as close to reality as possible.

Ethical Approval
The protocol followed in this study adhered to the updates of the Declaration of Helsinki [54], and it was approved by the Committee on Biomedical Ethics of the University of Extremadura (198/2019).

Statistics
Microsoft Office TM Excel v.16 (Redmond, WA, USA: Microsoft Corporation), FAC-TOR v.10.10.02 (Tarragona, Spain, ESP: Rovira i Virgili University) and IBM TM SPSS v.25 (IBM Corporation, Armonk, NY, USA) were used for data analysis. A semiconfirmatory factor analysis (SCFA) was carried out, that is considered appropriate to prevent errors included in the "Little Jiffy" approach [55,56]. FACTOR performs at the same time an exploratory analysis offering goodness-of-fit indicators, so an additional confirmatory factor analysis is not necessary [57][58][59][60].
Considering the ordinal nature of the data, polychoric correlations using the robust unweighted least squares method with oblique rotation were employed. The Kaiser-Meyer-Olkin (KMO) and Bartlett's sphericity tests were used as indices of sampling adequacy [61,62]. Due to the comprehensive nature of the tool, which is intended to be used as a developmental scale to monitor BADLs acquisition, and in the absence of cross-loadings, some items with loadings above 0.30 have been included [63].
To assess the goodness-of-fit, we used the chi-squared probability setting as appropriate non-significant values (p > 0.05); the comparative fit index (CFI) and the nonnormed fit index (NNFI); the root mean square error of approximation (RMSEA); and the root mean square of residuals (RMSR) [62,64].

Description of the Basic Activities of Daily Living Assessment in Preschoolers Tool
The Basic Activities of Daily Living Evaluation in Preschoolers (BADL-P), a novel questionnaire created for Spanish preschoolers during this study, was used. The BADL-P included 84 items, distributed in 4 scales with 9 factors that provide a theoretical model to support the instrument. Eating, personal hygiene and dressing are BADLs themselves, as explained, while the daily functioning scale includes information about cognitive skills critical for good BADLs performance ( Figure 2).

Description of the Basic Activities of Daily Living Assessment in Preschoolers Too
The Basic Activities of Daily Living Evaluation in Preschoolers (BADL-P), a nove questionnaire created for Spanish preschoolers during this study, was used. The BADL-P included 84 items, distributed in 4 scales with 9 factors that provide a theoretical mode to support the instrument. Eating, personal hygiene and dressing are BADLs themselves as explained, while the daily functioning scale includes information about cognitive skill critical for good BADLs performance ( Figure 2). Most of the items are written in positive form, and those in negative were recoded This instrument must be completed by interviewing main caregivers. Response option for every item are always, sometimes, never, or not known/no opportunity. Therapists o educators must obtain evidence that caregivers' answers are as close to reality as possible

Ethical Approval
The protocol followed in this study adhered to the updates of the Declaration of Hel sinki [54], and it was approved by the Committee on Biomedical Ethics of the Universit of Extremadura (198/2019).

Statistics
Microsoft Office TM Excel v.16 (Redmond, WA, USA: Microsoft Corporation), FAC TOR v.10.10.02 (Tarragona, Spain, ESP: Rovira i Virgili University) and IBM TM SPSS v.2 (IBM Corporation, Armonk, NY, USA) were used for data analysis. A semiconfirmator factor analysis (SCFA) was carried out, that is considered appropriate to prevent error included in the "Little Jiffy" approach [55,56]. FACTOR performs at the same time an ex ploratory analysis offering goodness-of-fit indicators, so an additional confirmatory facto analysis is not necessary [57][58][59][60].
Considering the ordinal nature of the data, polychoric correlations using the robus unweighted least squares method with oblique rotation were employed. The Kaiser Meyer-Olkin (KMO) and Bartlett's sphericity tests were used as indices of sampling ade quacy [61,62]. Due to the comprehensive nature of the tool, which is intended to be used as a developmental scale to monitor BADLs acquisition, and in the absence of cross-load ings, some items with loadings above 0.30 have been included [63].
To assess the goodness-of-fit, we used the chi-squared probability setting as appro priate non-significant values (p > 0.05); the comparative fit index (CFI) and the non normed fit index (NNFI); the root mean square error of approximation (RMSEA); and th root mean square of residuals (RMSR) [62,64]. Most of the items are written in positive form, and those in negative were recoded. This instrument must be completed by interviewing main caregivers. Response options for every item are always, sometimes, never, or not known/no opportunity. Therapists or educators must obtain evidence that caregivers' answers are as close to reality as possible.

Ethical Approval
The protocol followed in this study adhered to the updates of the Declaration of Helsinki [54], and it was approved by the Committee on Biomedical Ethics of the University of Extremadura (198/2019).

Statistics
Microsoft Office TM Excel v.16 (Redmond, WA, USA: Microsoft Corporation), FACTOR v.10.10.02 (Tarragona, Spain, ESP: Rovira i Virgili University) and IBM TM SPSS v.25 (IBM Corporation, Armonk, NY, USA) were used for data analysis. A semiconfirmatory factor analysis (SCFA) was carried out, that is considered appropriate to prevent errors included in the "Little Jiffy" approach [55,56]. FACTOR performs at the same time an exploratory analysis offering goodness-of-fit indicators, so an additional confirmatory factor analysis is not necessary [57][58][59][60].
Considering the ordinal nature of the data, polychoric correlations using the robust unweighted least squares method with oblique rotation were employed. The Kaiser-Meyer-Olkin (KMO) and Bartlett's sphericity tests were used as indices of sampling adequacy [61,62]. Due to the comprehensive nature of the tool, which is intended to be used as a developmental scale to monitor BADLs acquisition, and in the absence of cross-loadings, some items with loadings above 0.30 have been included [63].
To assess the goodness-of-fit, we used the chi-squared probability setting as appropriate non-significant values (p > 0.05); the comparative fit index (CFI) and the non-normed fit index (NNFI); the root mean square error of approximation (RMSEA); and the root mean square of residuals (RMSR) [62,64]. Ordinal alpha was used to find out the internal consistency of the tool. It represents an alternative to Cronbach's Alpha for ordinal items, being >0.70 values considered as acceptable and >0.80 preferred [65,66].
As external validity criteria, descriptive and contrast results are provided according to sociodemographic characteristics of the sample. Additionally, preliminary data on the classification ability of the questionnaire are presented through the analysis of the receiver operating characteristic (ROC curves), comparing with a sample of 11 subjects with ASD in addition to the sample of 303 typically developing participants.

Item Analysis and Internal Structure of the Questionnaire
The BADL-P study version was initially composed of 113 items. After performing the analysis, 29 items were deleted, so the final version was finally formed by 84 items distributed in four scales with nine factors (Figure 3). The instrument is created in Spanish (Supplementary Material), but items are provided in English to facilitate the reading of the paper. Ordinal alpha was used to find out the internal consistency of the tool. It represents an alternative to Cronbach's Alpha for ordinal items, being >0.70 values considered as acceptable and >0.80 preferred [65,66].
As external validity criteria, descriptive and contrast results are provided according to sociodemographic characteristics of the sample. Additionally, preliminary data on the classification ability of the questionnaire are presented through the analysis of the receiver operating characteristic (ROC curves), comparing with a sample of 11 subjects with ASD in addition to the sample of 303 typically developing participants.

Item Analysis and Internal Structure of the Questionnaire
The BADL-P study version was initially composed of 113 items. After performing the analysis, 29 items were deleted, so the final version was finally formed by 84 items distributed in four scales with nine factors (Figure 3). The instrument is created in Spanish (Supplementary Material), but items are provided in English to facilitate the reading of the paper. The factor structure of the resulting dimensions and the factor loading of each item are presented below.

Eating Scale
A KMO value of 0.68, and Bartlett's test, p < 0.001 were both good enough to carry out the SCFA. However, 12 items did not reach <0.30 so 16 items formed the final version of the scale.
Eating refers to all the tasks or activities that help in manipulating, keeping food or fluids in the mouth and swallowing [2]. We found an interpretable solution with three factors which explores: (1) items related to sensory integration, (2) items associated with social, educational, and cultural behaviours that must be learnt to be considered nicely behaved during mealtime, and (3) items about hand skills with food, fluids, cutlery, or containers to perform self-feeding (Table 3). The factor structure of the resulting dimensions and the factor loading of each item are presented below.

Eating Scale
A KMO value of 0.68, and Bartlett's test, p < 0.001 were both good enough to carry out the SCFA. However, 12 items did not reach <0.30 so 16 items formed the final version of the scale.
Eating refers to all the tasks or activities that help in manipulating, keeping food or fluids in the mouth and swallowing [2]. We found an interpretable solution with three factors which explores: (1) items related to sensory integration, (2) items associated with social, educational, and cultural behaviours that must be learnt to be considered nicely behaved during mealtime, and (3) items about hand skills with food, fluids, cutlery, or containers to perform self-feeding (Table 3). Personal hygiene refers to obtain and use toileting supplies to get or keep clean, including toileting needs, brushing, washing up, bathing and grooming [2]. We got an interpretable solution with three factors: (1) all the items related to brushing teeth, (2) the ones related to toileting needs, and (3) the rest of personal hygiene and grooming activities (Table 4).

Dressing Scale
A KMO value of 0.952 and a p < 0.001 for Bartlett's test were obtained. The scale had 30 items, but nine items were deleted, so 21 items form this scale.
Dressing refers to being able to select clothes, shoes, and accessories, putting them on and taking them off, and getting dressed and undressed in the right way [2]. This scale is formed only by one factor, as presented in Table 5.

Daily Functioning Scale
A KMO value of 0.737 and a p < 0.001 for Bartlett's test were found. Only 2 items were deleted, so the final version got 17 items on this scale. This scale joins cognitive aspects that influence BADLs performance, and it is composed of two factors ( Table 6): higher-order EF (eight items) and core EF (nine items). The child brushes his teeth after eating without being told by an adult. 0.545 The child brushes for at least one minute.  Table 5. Factorial solution of the Dressing scale.

Item Factorial Weight
The child makes sure that the label of the clothes is in the right place.  Table 6. Factorial solution of the Daily functioning scale.

Item Factorial Weight
Factor 1: Higher-order executive function.
The child begins his activities of daily living in a reasonable time from the adult's direction. 0.517 The child can perform his activities of daily living without the help of an adult. 0.554 The child persists in their activities of daily living although he finds difficulties. 0.306 The child finishes his activities of daily living at an appropriate time. 0.521 The child becomes aware of the mistakes he makes in his activities. 0.559 The child tries to solve problems while performing an activity. 0.732 The child performs his daily activities without unnecessary stops. 0.642 The child performs his daily activities in a logical order. 0.649 Factor 2: Core executive function.
The child gets frustrated quickly when cannot perform an activity. 0.428 The child has more tantrums than expected for his age.  Table 7 provides correlations between the different factors of every scale. All BADLs factors are related to each other. Likewise, EF is related to all BADLs except oral sensitivity. Thus, oral sensitivity seems to function independently, and it is only weakly and negatively related to core EF.  Table 8 shows that all the indices, calculated with FACTOR software, are acceptable.

Reliability
Ordinal alpha (Table 9) was used to find out the internal consistency of the BADL-P. Results are acceptable (>0.70) or preferred (>0.80).  Table 10 shows descriptive and contrast statistics referring to the participants' scores considering sex (boys and girls). Significant differences of moderate magnitude according to sex in the toilet management dimension (p < 0.04; d > 0.56), with differences in favour of the girls' group, were observed. Moreover, significant differences of large magnitude are observed in the core EF (p < 0.001; d > 1.22) in favour of girls.  Table 11 describe descriptive and contrast statistics after grouping participants according to the age of the two stages within early childhood education (3-4 and 5-6 years). Participants' scores indicate significant and high magnitude differences in almost all the dimensions, except in oral sensitivity (p < 0.22; d > 0.19) and core EF (p < 0.001; d > 1.22). These findings indicate a strong effect of age on the acquisition of BADLs (Table 11).

The Basic Activities of Daily Living Assessment in Preschoolers Discrimination Ability between Typically Developing Participants and a Sample of ASD Participants
Although this manuscript presents the preschool version of our tool in typically developing children, our goal is that it can be used with children with neurodevelopmental disorders. Thus, a preliminary comparison of 11 typical children compared to 11 children with ASD (not included in our study sample) is presented to test the ability of the BADL-P to discriminate between performance on ADLs between typical development and ASD.
As illustrated in Figure 4 and Table 12, the area under the curve (AUC) shows that the tool can classify beyond chance between typically developing participants and participants with ASD (p < 0.00). The ability to classify between the two groups of greater magnitude is related to the personal hygiene scale and the total score of the questionnaire.

The Basic Activities of Daily Living Assessment in Preschoolers Discrimination between Typically Developing Participants and a Sample of ASD Participants
Although this manuscript presents the preschool version of our tool in ty veloping children, our goal is that it can be used with children with neurodev disorders. Thus, a preliminary comparison of 11 typical children compared to with ASD (not included in our study sample) is presented to test the ability of P to discriminate between performance on ADLs between typical developmen As illustrated in Figure 4 and Table 12, the area under the curve (AUC) the tool can classify beyond chance between typically developing participants ipants with ASD (p < 0.00). The ability to classify between the two groups of g nitude is related to the personal hygiene scale and the total score of the questi

The Basic Activities of Daily Living Assessment in Preschoolers Theoretical Model
This study presents the BADL-P theoretical model, a novel tool for Spanish children between 3-6 years, with good psychometric properties according to preliminary data provided, practical and useful for both, early school educators and early care services educators and therapists. It was initially composed of 113 items, and after the study, they were reduced to 84. The model is divided into four scales: eating, personal hygiene, dressing, and daily functioning scales. The last scale offers a screening of cognitive factors which may influence during ADLs performance. In the eating scale, we got a structure with three factors and 16 items: oral sensitivity (three items), good manners (seven items) and manual dexterity (six items). In the personal hygiene scale, three factors and 30 items: brushing teeth (six items), toileting management (nine items) and hygiene and grooming (15 items). The dressing scale is composed of only one factor with 21 items. Finally, the daily functioning scale is composed of two factors and 17 items: higher-order EF (eight items) and core EF (nine items) during ADLs performance.
In our previous study [68], we presented the scholar version for children between six and 12 years (ADL-E). It was formed by a total of 84 quantitative items and six additional qualitative items only for girls about menstruation management. All items were distributed in the same four scales, but with different factors that outlined the progressive specialization in the BADLs from birth through lifetime. Thus, comparing the preschool version (BADL-P) with the school version (ADL-E), we observe how the dimensions are gradually expanded, as the skills are subdivided as the children grow up, which presents an indicator of validity [17,69].
As observed in Table 7, which shows correlations between factors, core EF, is closely related to BADLs performance. Thus, it is important to determine how problems in both of them could be affecting BADLs performance [30,70,71]. Therefore, our tool might help clinicians to determine whether a more in-depth assessment in one or another direction is needed.

The Basic Activities of Daily Living Assessment in Preschoolers and Other Tools
As exposed, ADLs performance is influenced by both internal and external factors. Occupational development is the result of the dynamic interaction of person, activity and environment [6]. In Spain, some instruments for measuring BADLs are available, but as previously exposed, they present some limitations. On the one hand, sometimes occupational assessment is inferred from instruments that assess adaptive behaviour, described as suitable behaviours for independent living. However, this concept includes some or other areas or activities depending on the classification consulted. For example, Kamphaus (1987) talks about physical/motor, self-help/independence, interpersonal/social, cognitive/communication and responsibility. Meanwhile, Widaman et al. (1993) mention cognitive competence, social competence, social maladaptation, and personal maladaptation [53]. On the other hand, ADLs conceptualization has reached a huge agreement [2,72,73]. The BADL-P structure is focused on ADLs, which is concrete and unambiguous. Some of the most widely used instruments based on adaptive behaviour concept, mix BADLs performance with other social aspects, not covering the BADLs full range of activities, or being their items divided into different sections or categories not according to their nature. For example, the Battelle Developmental Inventory [51], or the Inventory for Client and Agency Planning [49] include few items on BADLs performance. In the Adaptive Behavior Assessment System II [74], the items are divided into different sections which make them difficult to understand. It is also important to note that some tools, such as the Carolina Curriculum [75] or the Merrill-Palmer Revised Scales [52], do not cover the full preschooler stage. Moreover, many of these instruments are available in Spanish, but we have not found information about their validation; e.g., the Pediatric Evaluation of Disability Inventory [76] or the Vineland Adaptive Behavior Scales II [44], with the risk of not being culturally adapted.

The Basic Activities of Daily Living Assessment in Preschoolers Psychometric Properties
We have created our instrument after performing an exhaustive review, using an experts' group, carrying out a pilot study with families, conducting the study itself and carrying out the corresponding statistical analysis. In relation to statistics, we have carried out the factorial analysis with FACTOR software, which can perform SCFA what means that while performing an exploratory factor analysis shows goodness-of-fit indices to prove if the factorial solution offers a suitable adjustment. The SCFA has been used to validate instruments in natural [77,78], social [79][80][81][82][83][84][85], and health sciences [30,86,87]. Thus, it is a widely contrasted procedure.
As reflected in results section, the goodness-of-fit indices related to the construct validity of the test structure are highly adequate. The descriptive and contrast statistics indicate significant differences related to the two age groups analyzed (2-4 and 5-6 years). It demonstrates that ADLs performance is acquired throughout development and our instrument seems sensitive for analyzing this progression. Furthermore, construct validity is reinforced by additional data on the instrument's ability to classify between typical participants and a small group of ASD individuals. ROC curves show the instrument's ability to discriminate adequately on some of the dimensions (Hygiene = 0.95 and Total = 0.93). As it can be noticed, the scores that most discriminate between typical development and ASD preschoolers are the personal hygiene scale and the total score. Concerning hygiene activities, they have a greater contextual load (noises, smells, visual stimulation by mirrors and reflections) and are longer and more precise than feeding and dressing. Therefore, they have a greater demand of core EF. The reliability index provided by the ordinal alpha [88][89][90][91] shows an acceptable level of internal consistency (α > 0.70). In summary, this preliminary study offers promising indicators of reliability and construct validity.

Limitations and Future Lines
This research has some limitations. We are aware that we need to check the concurrent validity using well-established tools and predictive validity, conducting longitudinal studies to check the capacity of the instrument to detect occupational performance issues development of the children. However, we have not found validated tools that support BADLs construct in Spanish preschoolers. Another limitation is the small sample size of ASD children. This is the reason why we are talking about preliminary results, and we are working to get a larger sample size to increase the power of results.
Several future lines will be developed. In this manuscript, we have presented the BADL-P for preschoolers. In a previous study, the scholar version was tested [68]. We are also interested in exploring the skills required to achieve BADLs during the 0-3 years stage. In this line, IADLs (caring for others, communication management, community mobility, financial and home management, spiritual activities, safety and emergency maintenance, and health management [2]), which are performed at home and in the community, gain importance during adolescence. Thus, it could be interesting to explore an instrument in this scope. Furthermore, our final goal is testing our tools in children and adolescents with neurodevelopmental disorders diagnosis [11], which includes intellectual disability, ASD, attention deficit and hyperactivity, specific learning, motor, and communication disorders. These children usually have poorer ADLs performance compared with typical development children, and some studies draw different occupational profiles in these individuals [12,13,92,93]. At the stage studied, the development of ADLs is closely linked to maturational processes, in addition to other contextual processes, such as the patterns of parenting in each cultural setting. The translation of the scale into other languages and its adaptation to other cultural contexts will bring greater clarity to the influence of both aspects on the development of ADLs. Although this paper presents preliminary discrimination data with a small sample of ASD subjects, we intend to check the specificity-sensitivity of our tools in clinical samples of children with neurodevelopmental disorders.
Finally, we want to highlight the importance of carrying out practices and policies to support children with disabilities to participate in society, even those with "invisible disabilities" like children with neurodevelopmental disorders. Thus, this project is aligned with objectives 3 ("Good-health and well-being") and 4 ("Quality education") of the 2030 Agenda for Sustainable Development [94].

Conclusions
Based on our preliminary results, we conclude that BADL-P is a practical and easy to use tool with good construct validity and reliability properties for assessing BADLs occupational performance in Spanish preschoolers between three and six years.
Although this tool was developed to test BADLs occupational performance in typical development preschoolers aged from three to six years, preliminary results suggest that this tool could discriminate between typically developed children and their peers with neurodevelopmental disorders. However, future studies with larger sample sizes are needed to increase the power of results. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
The datasets used during the current study are available from the corresponding author on reasonable request.

Conflicts of Interest:
The authors declare no conflict of interest.