Daily time management and autonomy in school-age children with ADHD, intellectual disabilities, and typically developing children show different patterns

Children with ADHD and those with intellectual disability (ID) often have problems in daily time management (DTM) and the underlying time-processing ability (TPA). It is, however, less well-known how DTM and TPA may impact children’s everyday autonomy. The purpose of this study was to investigate DTM, TPA and self-rated autonomy in the activities of everyday life among children aged 9-15 years with ADHD ( n = 47), with ID ( n = 47) and typically developing (TD) children ( n = 47). Method A descriptive, comparative and cross-sectional design was used. Group comparisons and cluster analysis with one-way analysis of variance (ANOVA) with Tukey post-hoc tests and bootstrapping were used to analyse the data. Results

based on a person's cognitive functioning related to time (2,(4)(5)(6); namely, a person's TPA (2). TPA develops during childhood and adolescence and seems to follow the developmental stages, as indicated by chronological age in children without disabilities (3,7). TPA is an unidimential construct containing three categories: time perception, time orientation (divided into two sub-levels: time concepts and objective time) and time management which can be seen as different levels of complexity of TPA (8). Time perception (experience of time and durations of activities) and time orientation (i.e. to tell time and to know what day and month it is) are basic levels of TPA and are necessary for time management (2,6). Time management, defined as ordering events in chronological sequences and allocating the appropriate amount of time for activities, is an important part of executive functions (5,6). Executive function refers to brain functions that activate, organize, integrate and manage other functions (9,10). In a study of young children aged 5-10 years, with and without disabilities, the results showed four typical patterns related to the chronological age of the children without disabilities (7). There were children with and without disabilities in all patterns, but children with a diagnosis were significantly older in all groups except for the group with Several researchers have emphasised deficiencies in the executive functions as a basic problem for children with ADHD (9,19). Children with ADHD have been shown to have a delayed maturation of the cerebral prefrontal regions, which are important for executive functions, including time management (20,21). Children with ADHD also seem to have a different sense of time than typically developing children (22). Their ability to discriminate and reproduce time intervals and to make retrospective time estimations has been shown to be impaired (23)(24)(25). The perception of time is mainly researched in experimental studies (24,26,27). Mioni et al. (28) found that children with ADHD performed less precisely in time-based prospective memory tasks and that time perception predicted prospective memory accuracy. Children with ADHD may also have reduced ability to value time in relation to the actual duration of daily activities (7). These difficulties are apparent mainly in the experience of time, and planning and organising the plan when carrying out daily activities, at home, at school and during play (29). In a study of Lindblad and colleagues (30) children with ADHD 6-16 years had lower adaptive functioning compared to children with mild intellectual disabilities (ID).

Children with ID and difficulties with time
Children with ID have a cognitive development, including the development of TPA, that is slower than in children without disabilities, and the level of abstract thinking as an adult is lower (31). It is well known that difficulties with abstract concepts such as the understanding of time concepts (31,32) and a reduced working memory (31) are common in children and adults with ID. This affects the practical skills in activities in daily life (33).
Clinically, children with ID have been targeted with interventions directed towards time deficits for many years, but nevertheless there are few studies on TPA and DTM (32). In one of the few studies involving children with ID, the children made more errors in prospective memory tasks than children without disabilities (34). They also had a weaker time reproduction than children without disabilities. It has been shown that children and adults with ID benefit from time-assistive devices to enhance DTM and TPA (35)(36)(37)(38) and that they can improve their TPA by training in low levels of TPA that focuses on time perception and the duration of activities (39). The fact that children with ID experience limited participation and autonomy in school activities has been presented in previous studies (17,40).

Self-rated autonomy in children with ADHD and children with ID
Autonomy in children with disabilities is mostly studied in a school context. Results show lower participation and self-rated autonomy in children with disabilities compared to children without disabilities (17,40). In Eriksson et al. (40), 66 children aged 7 -12 years with and without disabilities were observed at school for one day and were also interviewed about participation and asked to self-rate their autonomy. The results showed that children with disabilities, mostly children with ID, ADHD and children with motor impairment, had lower participation and self-rated autonomy compared to children without disabilities. In Eriksson & Granlund (17), a comparison between 959 children with and without disabilities in the ages 7 to 17 years, children with disabilities, including children with ID, rated their participation and autonomy in school-activities lower than children without disabilities. Studies in children with ADHD and children with ID self-rating their autonomy outside school context are sparse. We only found two studies with children selfrating their autonomy in everyday activities. In Janeslätt et al. (2) 118 children with different diagnoses, including ADHD and ID, aged 6-11 years, self-rated their autonomy.
Also parent ratings of DTM and measurements of TPA were conducted. Results showed a significant relation between self-ratings of autonomy, parents' ratings of DTM and the children's TPA. The same pattern was shown in Janeslätt et al (7) were children with (n=77) and without (n = 89) diagnosis and aged 5-10 years self-rated their autonomy. As in the previous study, autonomy and DTM were related to the children's TPA. Children with disabilities were found in different clusters, showing diversity in TPA, DTM and autonomy not explained by diagnosis.
Previous studies on TPA in children with ADHD and children with ID have especially focused on the first sub-level of TPA, time perception (22-26, 34, 41) ), and a few studies on the sub-level of time management (34). All were laboratory studies using standardised tests. We found only two studies investigating the whole construct of TPA including time perception, time orientation and time management and using more practical tasks reflecting real-life activities (2,7). However, in these studies the children were younger (age 5-10 years and 6-11 years) and also children with other diagnoses than ADHD and ID participated. Also studies on self-rated autonomy in children with ADHD and children with ID outside school-context are sparse (42). Despite indications of differences in TPA, DTM and autonomy not explained by age or diagnosis, reported in the study by Janeslätt et al. (7) there is, as far as we know, no study investigating and comparing patterns of TPA, DTM and autonomy in children aged 9-15 with ADHD, ID and typically developing children (TD).
There probably are different dimensions of TPA in children that develop individually depending on age, diagnosis, gender, etc. Also it is possible that such development differs in children with functional variations compared to TD children. To investigate such patterns could give important knowledge on which interventions could be individualised.
The aim of this study is to investigate DTM, TPA and self-rated autonomy in everyday activities in children aged 9-15 years with ADHD, compared to children with ID and to TD children.
Research questions:

1.
Are there any differences, and if so what, in TPA, DTM, and self-rated autonomy in everyday activities between children with ADHD, children with ID and TD children?

Children with ADHD
A consecutive sampling was used in the study and the children with ADHD were recruited from three child and adolescent psychiatric clinics (CAPs) and one children´s habilitation service (HAB) in Sweden between September 2012 and Mars 2015. Inclusion criteria were a diagnosis of ADHD determined in accordance with DSM-IV criteria by an experienced CAP specialist after a thorough neuropsychological investigation encompassing careful clinical examination and questionnaires, a steady prescription of ADHD medication for at least three months, age 9-15 years and parent-reported difficulties with DTM, and ten points or more on a clinical rating of 15 statements related to problems with DTM (a subscale of the Five to Fifteen parent questionnaire (44). Examples of statements were if the child was stressed by time limits, had difficulties in using a watch or if the child was "lost in his/her own world" and was not aware of the passage of time. Further examples were when a child had obvious difficulties in carrying out and completing morning routines and arriving in time for school or had difficulties in calculating the time span for daily activities and leisure activities (for more information see 45). Exclusion criteria were ID (IQ<70, autism spectrum disorder, or language barriers (e.g. not being able to answer questionnaires in Swedish). This resulted in 47 children with ADHD. Parents of the children were asked to participate in the study during ordinary monitoring visits to CAP or HAB. Those who agreed to participate were given written invitations to a personal visit for the data collection.
Data collection was conducted with the child and the parent separately (see 45 for more details).

Children with ID and TD children
To enable comparisons each child with ADHD was matched, pairwise, with a child with ID TD children were recruited as a convenience sample by the participants in courses for KaTid certification from the normal population, self-reported by the parents being healthy and having no diagnosis, and thereafter included in the database. In total there were 141 participants.

Procedure
The children's TPA was measured using a structured assessment (KaTid), and the children's DTM was rated using a parent questionnaire (Time-Parent scale). The children's autonomy was rated by self-reporting (self-report Autonomy scale).

Instruments
Kit for assessing time-processing ability (KaTid) (6) is an instrument for the assessment of Using the Autonomy scale of the instrument "Children's participation in school, students' assessment forms" (16,17), the children rated their autonomy. This scale is an adapted short version of the Autonomous Functioning Checklist Self-determination scale (46) (8) and it has been demonstrated that a version using the first 12 items can be used to measure self-rated autonomy equally as well as the longer versions (7). In this study, all three versions were used. If needed, the child was offered support from the occupational therapist by reading or explaining the statements. The response scale was also offered as cognitive adapted with pictures.

Ethical aspects
The ethical guidelines stipulated by the Helsinki Declaration (48)  Written informed consent was obtained from all parents and from the older children/adolescents in the study.

Data analysis
All data analysis was performed using IBM SPSS Statistics version 26, selecting a significant level of .05 and a confidence interval of 95%.

Comparisons between groups
Variable-based analysis was used to compare TPA, DTM and self-rated autonomy between children with ADHD, ID and TD children. To make it possible to compare the data for all children, some transformations of the different scales were needed (49). Data collected with KaTid-Child (n=37) were transformed into KaTid-Youth scores using a transformation scale, making the score sums comparable (6). Comparisons were made concerning differences in age, TPA, DTM and autonomy, and between clusters, using one-way analysis of variance (ANOVA) and bootstrapping (see above). Chi-square tests were used to analyse differences between the clusters regarding sex and diagnosis (54). To determine whether there were differences within the clusters, sub-group analyses were also performed regarding age and sex in the two clusters with the largest numbers of participants.

Results
Mean age of the children with ADHD was 11.5 yr. (SD 1.93), children with ID 11.6 yr. (SD 1.83) and for the TD children 11.5 yr. (SD 1.90). Most of the children were boys (n =32, 68%).

Missing data
There was no missing data in TPA and DTM. In self-rated autonomy, there was missing data from one child with ADHD and from nine children with ID. A sensitive analysis did not show any significant differences using the whole sample compared to only using data from children with no missing data.

Time-processing ability
There were statistically significant differences between the groups, F (2,138) = 84. 49 children with ADHD and children with ID (p < .001 and between TD children and children with ID (p = .007). The ES were large or medium (Table 1).

Autonomy
There were statistically significant differences between the groups in autonomy, F (2, 128) 30.58, p < .001. TD children had the highest scores in both autonomy versions, followed by children with ADHD (Table 1) which is acceptable (Table 2).

Outliers
The first step in the cluster analysis was to identify a residue of outliers. The participants in the residue are held as being dissimilar to all other participants. There were two residuals found, both ID children. In total, 139 participants were included in the clusters.

Descriptives
There were statistically significant differences between clusters in age F (3.135) = 3.25, p = .024. The distribution of sex in the clusters varies between 57% and 86% boys. Still, there were no statistically significant differences in sex between the clusters (p = .756).
There were statistically significant differences between clusters according to diagnosis (p Descriptions of the participants in each cluster according to number, sex, diagnosis, mean age, TPA (total score, time perception, time orientation (concepts and objective time) and time management). DTM and self-rated autonomy are presented in Table 2. The results for each cluster are presented separately below.

Cluster A -(Skilled in all levels of TPA)
Cluster A is the largest (n = 79) and contains children from all groups, but children with ID are underrepresented (11%). TD children make up the largest proportion (47%) followed

Cluster C -(Skilled only in time perception)
Cluster C is small (n=7), and contains children with ADHD and children with ID, children with ID being overrepresented (71%). Mean age is 11.1 (SD 1.42; range 9.44-13.50).
Children with ID are older (M = 11.6) compared to children with ADHD (M = 9.7).
According to TPA, these children have a mean of 39% of total scoresi.e. the second lowest in the sample. Children in this cluster are skilled only in time perception and have difficulties with time orientation (both concepts and objective time) and time management ( Figure 2).

Cluster D -(Difficulties at all levels of TPA)
Cluster D is small (n = 7), and contains only children with ID. Children in this cluster are the oldest in the sample with a mean age of 12.5 (SD 2.24; range 9.66-15.58).
According to TPA, these children have a mean of 24% of total scores, which is the lowest in the sample. The children have difficulties at all levels of TPA but mostly with time orientation/objective time and time management (Figure 2).

Differences in TPA, DTM and self-rated autonomy in groups based on diagnosis
Children with ADHD had statistically significant lower scores on TPA and DTM compared to Given that children with ID had the lowest TPA in the sample, we might expect the parents of children with ID to rate their children's DTM as lowest, but they did not. One explanation could be that parents of children with ID have low expectations of their child's DTM because of their known limitations in intellectual and adaptive functioning that are the criteria for the diagnosis (33). In addition it is clinically known that children with ID often have difficulties related to time (32). Another potential explanation may be that the children with ID might have had access to time-assistive devices, to compensate for deficits in TPA. Since in Scandinavia persons with ID are the target group who have had access to time-assistive devices for the longest, especially low-tech products such as adapted weekly schedules and/or activity schedules (36,(56)(57)(58).
Children with ADHD had a lower mean score for autonomy than TD children. Janeslätt et al. (7) showed in a study of children aged 5-10 years, with and without a diagnosis, that a child's self-rated autonomy was related to their TPA. The higher TPA a child had, the higher they self-rated their autonomy. Peny-Dahlstrand and colleagues (13) also found that high observed executive functions were related to high levels of self-rated autonomy in children with spina bifida. That both decisional and executive autonomy are dependent on cognitive functions has been found in a number of studies (11)(12)(13). The fact that children with ID in the present study, who had the lowest scores for TPA, also had the lowest scores for self-rated autonomy is in agreement with this. The lower levels of TPA in children with ADHD and ID in our study, compared to TD children, could therefore be an explanation for the lower scores on self-rated autonomy compared to the TD children. The fact that autonomy is suggested to be a prerequisite for participation (11,15) highlights the importance of interventions supporting cognitive functions, including TPA, in children with ADHD and ID in order to enhance their autonomy and thereby support their participation.

Patterns of TPA in children with ADHD, children with ID and TD children
However, the differences between diagnoses groups described above do not take into account the diversity within the children with the same diagnosis. Therefore we went further with this first study of TPA with a person-oriented approach, based on all four subscales/dimensions of time-processing ability (see Figure 1)

Specific patterns of TPA depending on diagnosis and age
In the present study, there were statistically significant differences between clusters concerning diagnosis. Nevertheless, there are no signs of differences in the overall pattern of TPA, indicating that children with ADHD and ID have the same pattern of TPA development compared to TD children but for some of these children at a slower pace. The same was found in Janeslätt et al., (7) were children with disabilities were older than TD children in the same cluster. This indicates a need for targeted and early intervention to enhance development of TPA (7). Training of organizational, time management and planning skills (OTMP) is a well-established treatment in children and adolescents with ADHD (59) and interventions focusing on TPA as a complement are therefore needed.
Otherwise, the functional impact (of having ADHD or ID) may increase with age (60).
Children with ADHD were represented in three of the four clusters, further emphasising the diversity of TPA among children with this diagnosis. This is in contrast to the TD children who, not surprisingly, were only represented in the clusters with the most able children. The fact that children with ADHD were more than a year older than TD children in showed promising results for 10-17-year-old children with ID that significantly increased their TPA, in only eight weeks, with a new method for training low levels of TPA.

Patterns of daily time management and self-rated autonomy
Except for Cluster D (Difficulties at all levels of TPA), there were almost no differences in parent-rated DTM between clusters, although the clusters differed in TPA. This result conflicts with a previous study showing that DTM is related to a child's TPA (7) Interestingly, in the present study, there are contradictory results concerning DTM.
Analysis of differences between TD children, children with ADHD and children with ID resulted in statistically significant differences in DTM but this can't be seen in the comparisons of clusters. This leads to a need for further research on TPA and DTM in children with ADHD and ID and with larger samples.
In contrast to DTM, there were differences in the clusters concerning self-rated autonomy.
The patterns of autonomy seemed to follow the level of TPA. Clusters with high scores of TPA also have higher scores of autonomy. This is in line with the results in Janeslätt et al.
(7) concerning children aged 5-10 years with and without a diagnosis.

Methodological issues/limitations
A strength of the study is that two different methods were used for analysing the data: a group comparison (43) to answer the broader question of TPA in children with functional variations compared to TD children, and a person-oriented cluster analysis (53) to look into dimensional aspects of TPA. Comparing two or more groups on a specific subject is a useful method for revealing group differences (43). In the present study, both parent-ratings and self-ratings were used. This gives a broad picture of children's functioning in everyday life. To obtain information from both children and their parents provides opportunities to both perspectives and could give important information concerning the child's health and well-being (61,62).
The recruitment of children with ADHD had the purpose to find children that could benefit from the intervention described in Wennberg et al. (42). This makes the present study not representative for the proportion of DTM difficulties in all children with ADHD. A limitation is also the amount of dropouts of self-ratings of autonomy in children with ID. We don´t know the reasons except for two children (didn´t understand the questions and didn´t want to answer). One explanation of the dropouts could be that the number of statements was too time consuming and demanding for the children since this self-rating was often done at the same time as the KaTid-measurement and a self-rating of DTM. Another explanation could be that the children with ID were unfamiliar with self-reporting questionnaires.

Conclusions
The present study supports the hypothesis that children with ADHD and ID have the same Written informed consent was obtained from all parents and from the older children/adolescents in the study.

Consent for publication
Written informed consent for publication was obtained from each participant prior to data collection.

Availability of data and materials
The data that support the findings of this study are available from Linköping University but restrictions apply to the availability of these data, which were used under license for the current study. Data are thus not publicly available. Data are however available from the authors upon reasonable request and with permission of Linköping University.

Competing interests
The We also acknowledge Habilitering & Hälsa, SLSO for financial support The funding sources had no role in study design, the collection, analysis and interpretation of data, the writing of the report, or the decision to submit the paper for publication.

Authors' contributions
All authors, Birgitta Wennberg, Anette Kjellberg, Per A. Gustafsson, Lena Almqvist and Gunnel Janeslätt have contributed significantly to the manuscript and are in agreement on its content.  Time-processing ability (TPA) a as percentage of total score and subscale scores, Daily time management (DTM) b as percentage of total score and self-rated Autonomy c as percentage of total score, in the clusters.