Digital Devices Use and Language Skills in Children Between 8-36 Month

Background: Over the past decade, the use of digital tools has grown and research evidence suggests that traditional media and new media offer both benefits and health risks for young children. The abilities to understand and use language represent two of the most important competencies developed during the first 3 years of life through the interaction of the child with people, objects, events, and other environmental factors. The main goal of our study is to evaluate the relationship between digital devices use and language abilities in children between 8-36 month, considering also the influence of several variables. Materials and Methods: We conducted a cross-sectional observational study on 260 healthy children (140 males = 54%) aged between 8-36 months (mean=23.5±7.18 months). All the parents completed a self-report questionnaire investigating the use of digital devices by their children, and a standardized questionnaire for the assessment of language skills (MacArthur). Multiple linear regression was used to evaluate the relationship between different variables. Subsequent moderation analysis were performed to verify the influence of other factors. Results: W found a statistically significant negative correlation between the total daily time of exposure to digital devices and the Actions and Gestures Quotient (ß=-0.397) in children between 8-17 months, and between the total daily time of exposure to digital devices and Language Quotient (ß=-0.224) in children between 18-36 months. Sex, level of education/job of parents, modality of use/content of digital device do not significantly affect these relationships. Conclusion: In our study we found that a longer time of exposure to digital devices was related to lower mimic-gestural skills in children from 8-17 months and to lower language skills in children between 18-36 months, regardless of age, sex, socio-economic status, content and modality of use. Further studies are needed to confirm and better understand this relationship, but parents and pediatricians are advised to limit the use of digital devices by children and encourage the social interaction to support the learning of language and communication skills in this age group.

children or to manage children's behavior. Studies revealed that parents often give children devices when doing house chores, to keep them calm in public places, during meals and/or at bedtime to put their child to sleep [13,[26][27][28]. In Italy a recent survey described that 20% of children used a Smartphone for the first time during his first year of life. Moreover, 80% of children from 3 to 5 years old is able to use their parent's Smartphone. In addition, parents often use media as pacifiers, giving mobile devices to their child to keep them calm during the first (30%) and the second (70%) year of life [29][30]. The majority of the studies in literature are on the US population but there are very few studies on Italian infant, toodlers and preschoolers. For that reason we believe it is important to explore how mobile devices are managed by parents and how much this affects language development in Italian children under three years old. The main goal of the present study is to evaluate the language development in children between 8 to 36 months assuming that the use of electronic devices adversely affects language development but this happen considering the influence of several variables. We hypothesize that co-viewing and characteristics of the screen media stimuli influence the relationship between digital devices use and language development. In particular, we consider that there is a difference between children that use devices in active interaction with parent and children that use devices alone. We do not expect socioeconomic status differences as each child has full access to devices.

Sample selection
We conducted a cross-sectional observational study on 260 healthy children (140 males = 54%; 120 female = 46%) aged between 8-36 months (mean= 23.5±7.18 months), recruited from twelve kindergartens and nursery schools of the city of Salerno. All the children younger than or equal to 36 months were included; the exclusion criteria were the presence of medical or neuropsychiatric conditions that could affect language or neuropsychomotor development, and poor parental compliance to take parte into the study. All the parents were invited to a preliminary meeting with a specialist in Child Neuropsychiatry, in order to explain the methods and purposes of our research. Subsequently, two different self-report questionnaires were administered to the parents who provided their written informed consent. The first questionnaire aimed to investigate the use of DD by the children, while the second one was a standardized questionnaire for the assessment of language abilities (Il primo vocabolario del bambino PVB -Italian adaptation of the MacArthur-Bates Communicative Development Inventory -CDI). All the data were collected and examined by a single investigating neuropsychiatrist. This study was performed in accordance with the Helsinki declaration and was approved by the Campania Sud Ethics Committee (protocol number = N.0033986 March,01 2019).

Digital Devices Questionnaire (DDQ)
Digital Devices questionnaire consisted of two parts: a first section that collected general information, socio-demographic data and medical history (age, sex, family members, number of siblings, educational level and job of the parents, pregnancy, childbirth, psychomotor development, diagnosed pathologies); a second section, consisting of 12 items, exploring the use of DD by children, as follows: 

Il primo vocabolario del bambino (PVB) -Italian adaptation of the MacArthur-Bates Communicative Development Inventory (CDI)
The language skills of the children were assessed through a standardized questionnaire. PVB is a standardized questionnaire for parents of children aged between 8 and 36 months, used both in research and in clinical practice for assessing communication and language in children with typical and atypical development. Given the physiological changes in language development between the first and third year of age, two forms have been created: the "Gestures and Words" Form, for children between 8 and 17 months, and the "Words and Phrases" Form, for children between 18 and 36 months. All the raw scores, are converted into age-weighted scores. In the "Gestures and Words" Form three age-weighted scores are considered: the Actions and Gestures Quotient (AGQ), the Language Understanding Quotient (LUQ) and the Language Production Quotient (LPQ). In the form "Words and Phrases" is considered only the Language Quotient (LQ). The age-weighted scores have mean=100 and standard deviation (SD)=15; scores below 70 (-2SD) are considered below the norm.

Statistical analysis
All data were expressed as mean, standard deviation and proportions/percentage, and subjected to descriptive statistics analysis. A preliminary normality test was performed in order to verify the data distribution (Shapiro-Wilk Normality Test). Multiple linear regression analysis was used to evaluate the relationship between different variables. Subsequent moderation analysis were performed to verify the influence of other factors. Bonferroni correction for multiple comparisons has been applied. All data were analyzed using the Statistical Package for Social Science, version 23.0 (IBM Corp, 2015); p-values less than or equal to 0.0025 were considered statistically significant.

Sample characteristics
Our sample included 260 children (140 males=54% and 120 females=46%) aged between 8-36 months (mean=23.5±7.2months). The sample was subsequently divided into two sub-groups: 72 children between 8-17 months (mean=13.8 ±3.5) and 188 children between 18-36 months (mean=27.1 ±4.4), based on the typical differences in language competences of the two group age and, therefore, on the different standardized questionnaires administered. Socio-demographic and clinical data suggests that the sample is representative of a population with a typical psychomotor development (first steps mean age =12.6±2.0 months; first words mean age =12.8±4.2 months) and the two subgroups appeared homogeneous for the main characteristics analyzed. The socio-demographic characteristics of the sample are summarized in Table 1. In both groups the main reasons why parents allowed their children to use DD were "to entertain" (104/252, 42%) or "to calm the child" (91/252, 36%). The DD were frequently also used during meal time (94/252, 37%) or before the child went to sleep (23/252, 9%).
In few children, with a slightly prevalence in the older group, the parents reported that they did not respond to the their name when called (6/252, 2%), or didn't interacted with others (12/252, 5%) during DD use. A further 6% (16/252) appeared frustrated, with stubborn crying, if the DD was taken off.
Overall, the parents also reported sleep problems (including difficulty falling asleep and/or frequent nighttime awakenings) in about 33% (86/260) of the children, with a slightly prevalence in younger group (45% vs 33%).
Finally, 53% of parents (134/260) expressed concern about the health consequences of the DD use in their children, although only 19% of the parents (47/260) had already asked their pediatrician for advice on this topic.

Relationship between Digital Devices use and language skills in children
In the group of younger children, a statistically significant negative relationship was found between the total daily time of exposure to DD and the Actions and Gestures Quotient (AGQ) scores, through linear regression analysis (ß=-0.397; R2=0.158; p=0.001; Table 3; Figure 1).
Through subsequent moderation analyzes emerged that other factors such as sex, level of education/job of parents, modality of use/content of DD, and frequency of social activities do not significantly affect this relationship (Table 4).
On the other hand, no statistically significant relationship was found between the total daily time of exposure to DD and the Language Understanding Quotient (LUQ) and Language Production Quotients (LPQ) scores (Table 3).
The relationship between age of the first use of the DD and AGQ, LUQ and LPQ scores was also tested, but no statistically significant correlation was found (Table3).
In the group of older children a statistically significant negative relationship was found between the total daily time of exposure to DD and the Language Quotient (LQ) scores, through linear regression analysis (ß=-0.224; R2=0.060; p=0.001; Table 3; Figure 2).
Also in this case, we found that the variables considered in the subsequent moderation analysis did not significantly affect this relationship (Table 4).
No statistically significant relationship was found between the start age of use of the DD and the LQ scores (Table3).  x axis= hours/day of DD use; y axis = Actions and Gestures Quotient scores. x axis= hours/day of DD use; y axis= Language Quotient scores.

Discussion
The purpose of our study was to evaluate the use of digital devices in a population of children under 3 years old and correlate them with language skills. Our sample consisted of 260 children (54% male; mean age = 23.5±7.2 months), that was divided into two subsamples of children aged 8-17 months (n=72) and 18-36 months (n=188), according to the physiological variations of language skills in the two different age groups. The two subgroups appeared homogeneous for the main socio-demographic and clinical characteristics analyzed, and both are representative of a typically developing population (the stages of psychomotor development were described in the norm and children with neuropsychiatric problems were not reported).
The first important result that emerged from our survey was that almost all of the children (97%) used at least one of the most popular digital device, with a slight difference based on age. In particular, all the children between 18-36 months (100%) used DD against 89% of the children Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 3 August 2020 doi:10.20944/preprints202008.0070.v1 between 8-17 months. Our result is in line with the study of Zimmerman et al. (2007) in which 90% of parent reported that their children younger than 24 months use some form of electronic media [31]. The digital devices preferred by the children were the Smartphone (66%) and the Television (60%), with a slight preference for the Smartphone in the older than in the younger children group (71% vs 53%). The Tablet was in third place being preferred by 17% of the total sample and by 21% of children between 18-36 months. This data confirms that the Smartphone and the Tablet, considered among "new" digital devices, have become part of everyday life, and that children, even very young, are increasingly familiar with these tools [32].
In addition, parents reported that the first digital device used by the children was television (mean age of first use =11.3±5.2 months) followed by Smartphone (15.6 ±5.8 months), Tablet (18.5±6.1 months), PC (18.8±7.9 months) and Videogames (22.3±3.2 months). In our opinion, it is also important underline that in the group of younger children the ages of first use of DD are always lower than in the group of older children, for all the digital devices analyzed. This data would suggest a sort of "anticipation" of the age to DD exposure, which would seem increasingly early [31,32]. The average daily used of DD was about 2 hours/day, with a slight difference between the two groups (1.57 hours in children between 8-17 months and 2.34 hours in children between 18-36 months), confirming what has already emerged from the previous literature data. Vandewater et al. (2007) reported that forty percent of children between 6-23 months used digital media 2 or more hours/day [33] and Zimmerman et al. (2007) reported that on average infants younger than 24 months watched Television for 1-2 hours/day [31]. The most of children used digital devices in the presence of the parent/caregiver (75%) or siblings (9%), and only a minority of children completely alone (5%); 11% of parents report the use of automatic parental-control.
In line with previous literature data, we also found that parents using DD as peacekeeper for their children while they are engaged in other activities [34,35]; in both groups the main reasons why parents allowed their children to use DD were to entertain (42%), to calm the child (36%), during meal time (37%) or before the child went to sleep (9%).
In a small percentage of children aged 18-36 months, parents reported some atypical behaviors during the DD use: this children did not respond to the their name when called (2%), or didn't interacted with others (5%) during DD use. A further 6% appeared frustrated, with stubborn crying, if the DD was taken off. This data suggests that the use of digital devices in some children can become totalizing and lead to a reduction in social interaction and a difficulty in emotional regulation, as already reported in previous studies [36,37].
Overall, the parents also reported sleep problems (including difficulty falling asleep and/or frequent nighttime awakenings) in about 33% of the children, with a slightly prevalence in younger group (45% vs 33%). The association between sleep disturbance and excessive media use by children had already been reported. In particular, a recent cross-sectional study including 1117 toddlers showed that everyday use of a Tablet or Smartphone raised the odds ratio of a shorter total sleep time and a longer sleep onset latency regardless of other factors, such as temperament or type of screen exposure (TV or Videogames) [38]. Finally, 53% of parents expressed concern about the health consequences of the DD use in their children, although only 19% of the parents had already asked their pediatrician for advice on this topic. The most important result of the study concerned the relationship between language skills and time spent on digital devices by the children.
In children aged 8-17 months, we found a negative relationship between the total daily time of exposure to DD and the Actions and Gestures Quotient scores. Therefore, the children who spent more time to use digital devices showed a repertoire less rich in communicative gestures. It is important to consider that gestural and mimic ability are the main indicators of the pre-verbal communication skills of children in this age group.
In children aged 18-36 months, we found a negative correlation between the Language Quotient and the time spent on DD. In this case, greater use of DD by children was associated with less production of words. In both cases the correlation found was weak but significant and sex, age and socio-economic status did not significantly affect these relationships. For several years there has been a scientific debate about the association between the use of digital media and language skills in children. In terms of quantity of exposure, many authors suggest that the use of digital devices may represent a "passive" behavior that displaces fundamental learning opportunities for the child [37]. Population-based studies and a very recent meta-analysis showed associations between excessive TV viewing in early childhood and language, cognitive and socio-emotional delay; possible mechanisms responsible for this association would be inappropriate content, decrease in parent-child interaction and poor family functioning. Furthermore, earlier age of media use onset, cumulative hours of media use and contents were independent predictors of poor cognitive and linguistic skills [31,39-42].
In particular, evidence provides limited educational benefits of media use for children under 2 years and the American Academy of Pediatric discourage media exposure under this age [43]. It would seem, indeed, that before the age of 24 months, interaction with parents/caregivers is more effective in teaching verbal and non-verbal problem solving strategies [44]. On the other hand, there would be a difficulty learning from 2D representations before the 30 months (video deficit) due to the poverty of symbolic thought, control of immature attention and insufficient flexibility to transfer knowledge to the real world [45]. Before the age of two, therefore, children would learn language, sensorimotor and socio-emotional skills more through hand-on exploration and social interaction.
Our study is in line with this evidence, showing that a higher use of digital media was associated with less language skills; however, some authors disconfirm these results, showing an absence of correlation between language skills and time spent by children on digital media [46]. Other studies suggest, on the other hand, that the use of digital devices is not exempt from bringing benefits to children, even if they depend on the age, the stage of development, the characteristics of the child, the methods of use (co-viewing) and content (educational applications). The use of educational applications and parent co-viewing would be associated with an improvement in language skills in children [47,48]. In our study the co-viewing and the digital contents did not seem to significant affect the relationship between language and digital device use. This result could be due to not specifically investigating the use of "educational applications" and not to distinguish between "active" or "passive" co-viewing; therefore we can further explore these two aspects in future researches. However, we can also hypothesize that in the age group considered (8-36 months), these two factors are not as decisive as they are for older children, maybe because in this age group direct social interactions direct are the main source of language learning. Another limitation of the study is to use indirect questionnaires aimed at parents. Further studies would be needed, to assess language and communication skills through standardized direct tests [49].

Conclusion
Over the past decade, the use of digital tools has grown and research evidence suggests that traditional media and new media offer both benefits and health risks for young children.
In our study we found that a longer time of use of digital devices was related to lower mimic-gestural skills in children from 8-17 months and to lower language skills in children between 18-36 months, regardless of age, sex, socio-economic status, content and modality of use. Further studies are needed to confirm and better understand this relationship, but parents and pediatricians are advised to limit the use of digital devices by children and encourage the social interaction to support the learning of language and communication skills in this age group.