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Background: A digital micro-intervention offering attachment psychoeducational videos was explored regarding its feasibility in parents of children with severe disabilities. Method: A mixed-methods study (including daily diaries and one-time questionnaires) with 16 parents (75.0% female) of children with severe disabilities (up to 10 years of age) was done during a three-week intervention. Results: Parents were positive about the video series and almost no drop-out occurred. The videos stimulated their learning and thinking and offered parents some personal meaning. Preliminary efficacy tests showed no major changes in parents' parenting self-efficacy (PSE) or perceptions of statements on parent-child attachment. Conclusions: The study showed promising results regarding the micro-interventions' acceptability and implementation. The limited efficacy testing did not show major changes in parents' PSE. Further research is needed to investigate the differential relevance of the micro-intervention, based on parents' needs, as well as its optimal embeddedness in a broader intervention trajectory.

Background: Related to the target group of young children with a significant cognitive and motor developmental delay, the aims of this study were to obtain more insight into (the interrelations between) several characteristics of these children's expressive communicative behaviour and to explore associations between child behaviour, partner behaviour and contextual factors. Methods: A coding scheme was specifically developed and used to code observational data of 38 children. Three different communication-eliciting situations were video recorded. Potential communicative acts were detected, described, coded and counted within various coding categories. Data analysis mainly involved chi-square tests in combination with Cramer's V and Friedman's two-way analysis of variance by ranks. Findings: Potential communicative acts of young children with significant cognitive and motor developmental delay can be described in terms of focus, used modalities, level of initiative, communication complexity, signs of functionality and signs of emerging intentionality. The communicative focus of the children is mostly elicited by the prompt given by the communication partner and relates to certain behavioural modalities. Specific scaffolding behaviours of the partner are associated with the communication complexity of the children. Conclusion: This study provides some concrete suggestions on how to organise the interaction with these children.

Background: Individuals with developmental language disorder or Williams syndrome are reported to use more gestures than individuals with typical development. However, these two groups differ considerably in visuospatial and language skills, two skills that are hypothesized to shape gesture rate. Aims: We first examined whether children with both developmental language disorder and children Williams syndrome do indeed use more gestures. Our second aim was to disentangle the role of vocabulary and visuospatial skills in the use of supplementary gestures (i.e., containing unique information). To account for participant heterogeneity, analyses included both group comparisons and vocabulary and visuospatial skills at an individual level. As a third aim, the role of visuospatial skills was further examined in relation to gestures containing spatial content. Methods & Procedures: In a cross-sectional group design, three participant groups watched and then retold a cartoon--children with typical development (n = 25), children with developmental language disorder (n = 25) and children/young people with Williams syndrome (n = 14). Their narrations were transcribed and hand gestures were coded based on gesture-speech integration (redundant, adds information to particular lexical items, gives information that is entirely absent from speech) and spatial content. Participants' expressive vocabulary and visuospatial skills were measured. Outcomes & Results: Between-group comparisons showed that individuals with developmental language disorder or Williams syndrome did indeed use more gestures. Poisson loglinear modelling demonstrated that a relative higher use of supplementary gestures was determined by lower expressive vocabulary skills. Neither the group distinction nor visuospatial skills shaped the supplementary gesture rate nor spatial gesture rate. Conclusions & Implications: Regardless of neurodevelopmental condition or typical development, a higher use of supplementary gestures was influenced by expressive vocabulary skills. Children with lower vocabulary skills spontaneously capitalized on the multimodality of communication to express constituents that were not present in their verbal speech. This finding is a promising starting point for future gesture intervention studies examining whether implicit modelling of gesture use can encourage gestures even more in these children and if this allows them to achieve higher linguistic complexity. On a methodological note, the observed intra-group skill variability demonstrates that group comparisons need to be complemented with correlational measures accounting for skills at an individual level.

The communicative behavior of young children with significant cognitive and motor developmental delays is generally considered to be limited, idiosyncratic and non-intentional. At present, changes between and within children over time regarding their communicative behavior are hard to detect. This article describes an exploratory observational study that draws on data from the first data point of 38 children who are participating in a longitudinal project on the developmental trajectories of children with significant cognitive and motor developmental delays. The aims of this study were to (a) describe the participants' communicative behavior in detail with communication-related variables that reflect differences across individuals, (b) create summarizing variables and (c) explore whether subgroups of children can be detected. A self-developed coding scheme and descriptive statistics combined with correlational analyses were used, followed by a principal component analysis and visual inspection of the outcome of this analysis. The within-group differences related to communicative behavior was characterized using 16 variables. Based on these variables, three overarching components were formulated: communication proficiency, Expressions of Discomfort and Rejection and Differentiation According to Focus. All participating children were found to be unique in terms of their component scores and the relationship among their component scores.

Parents of children with severe disabilities have differing attachment-related support needs. An online vignette study with 25 experts, working in academia and/or clinical practice, was conducted to reflect upon the task of matching intervention components to families, based on their attachment strengths and needs. In two online rounds, the experts first completed an inventory of intervention (n = 25) components and second, they prioritised three components for particular families (n = 22). In addition, they reflected upon their argumentations for selecting these intervention components on different levels, either closely or more remotely connected to the children with disabilities themselves. The most common intervention choice across experts was to converse with parents to increase their understanding in the child's behaviours and communication. Experts justified their choices at various levels (child, parent, family unit, broader environment and professional). In that way, the current study provided an overview of the large number of elements that professionals and policy need to take into account when providing tailored intervention trajectories to these families. Systematically reflecting upon parents' attachment-related perceptions, strengths and (support) needs can furthermore stimulate professionals to prioritise their actions. It should, however, be embedded in a broader (diagnostic and contextual) intake procedure.

Displaying selective attachment behaviours is an important developmental milestone for children with severe or profound intellectual disabilities (SPID). In the current study, between-child differences in their selective emotional responses to comfort provided by parents versus strangers were observed. We explored links between these differences and parental sensitivity and motor competence. A home-based experimental observation was conducted in 38 parent-child dyads, exposing children to four naturalistic stressors and to comfort provided by either their parents or a stranger. Emotional behaviour (arousal and valence) was micro-coded and differentiation variables were constructed, reflecting the children's level of differentiation between the parent and the stranger. Parental sensitivity was coded using the Emotional Availability Scales. Results showed that these children's differentiated responses to comfort were related to children's motor competencies (particularly their fine motor skills), but not to parental sensitivity. This study shows the need to go beyond sensitivity to understand individual differences in the most basal aspects of attachment for children with SPID., Author(s): Sien Vandesande [sup.1] , Guy Bosmans [sup.2] , Paula Sterkenburg [sup.3] , Carlo Schuengel [sup.3] , Ines Van keer [sup.1] , Bea Maes [sup.1] Author Affiliations: (1) grid.5596.f, 0000 [...]

Background: Evidence shows that neurotypical individuals who stutter use fewer gestures than those who do not stutter. Presently, no research exists about the interaction of stuttering and gestures in individuals with Down syndrome. Method: Twenty-nine individuals with Down syndrome (7-19 years) of whom 16 stuttered and 13 spoke fluently and 20 neurotypical children (3-10 years) of whom 8 stuttered and 12 spoke fluently participated in this study. In spontaneous speech transcriptions, stuttering events and gestures were coded. Results: Comparisons of gesture frequency during stuttered and fluent speech inside the Down syndrome and neurotypical group show that the Down syndrome group uses significantly more gestures during stuttered than during fluent speech while no significant difference is seen in the neurotypical group. Conclusions: There is some preliminary evidence that individuals with Down syndrome try to compensate for their stuttering events, however, analyses on word level are necessary to confirm a successful compensation.

Background: It is generally acknowledged that parent social support is an important target for intervention. To explore the specific needs of parents of young children with a significant cognitive and motor developmental delay (SDD), we aim to chart the sources and perceived sufficiency of the social support they receive. Method: Within the context of a broader project, 42 parents of a young child with SDD filled out a questionnaire on contextual factors, including information on social support. Results: The majority of parents reported to receive (more than) sufficient support. Insufficiency is primarily reported with regard to practical support. Apart from the partner, grandparents of the child were the most common source of support. Conclusions: This study confirms the importance of professional support and work-life balance within this specific target group. Specific attention for practical support needs seems warranted considering the high basic care needs of these children.

Background: The feasibility and acceptability was explored of the newly-constructed Attachment Strengths and Needs Interview for parents of children with severe or profound intellectual disabilities. Method: A partially mixed methods approach (with focus on the quantitative data) was used to clarify parents' and professionals' viewpoints regarding the acceptability of the interview through websurvey-ratings. Results: Parents generally felt appreciated during or after the interview, were motivated to work on the proposed goals and felt the interview covered their actual needs, but were, however, more neutral on the aspects of reflection and learning. Professionals indicated that the interview gathered sufficient information on most elements of interest at the start of an intervention trajectory, but generally missed information on the origins of parents' questions and the families' expectations towards taking part in an intervention. Conclusions: The current study showed preliminary support for the feasibility and acceptability of the Attachment Strengths and Needs Interview, as part of a broader intake procedure, to inform attachment-focused interventions for parents of children with disabilities by identifying their strengths and needs.

Children with a significant cognitive and motor developmental delay (SDD) are vulnerable for the development of (future) behavioral and mental health problems. This paper aims to assess the social-emotional functioning of these children, both globally and in various domains. Semi-structured interviews with one or more primary caregiver(s) of 45 children were conducted and analyzed on 13 domains of social-emotional functioning, according to the Scale for Emotional Development - Revised (SED-R). The SED-R scoring system was slightly adapted in the current study in order to elucidate more subtle differences between children. A general delayed social-emotional development was found, with children functioning within different phases across domains and certain domains generally showing higher or lower scores. To capture the emotional needs of children with SDD, a more disaggregated scoring system seems valuable so that both the global level and the level per domain can be taken in consideration in designing interventions.

Children with a significant cognitive and motor developmental delay (SDD) are vulnerable for the development of (future) behavioral and mental health problems. To support children within this target group, knowledge on their social-emotional development is necessary. Therefore, in this paper, an explorative assessment of the changes in the social-emotional functioning of children with SDD over a two-year period was done. Yearly semi-structured interviews with one or more primary caregiver(s) of 25 children were conducted and analyzed on 13 domains of social-emotional functioning, according to an adapted version of the Scale for Emotional Development - Revised (SED-R). This study showed a lot of variation in individual and group patterns of change across the two-year period. Charting the social-emotional development in this target group is challenging and requires further in-depth analysis of individual trajectories as well as more fine-grained and long-term data collection.

Background: The realization of the family-centered approach (FCA) in home-based support (HBS) for families with children with an intellectual disability (ID) in Flanders was investigated, and parents' and family workers' perspectives were compared. The relation between parents' educational level, the family worker's education, and his/her experience in HBS; and parents' and family workers' judgments on the realization of the FCA was considered. Method: Parents (N ¼ 58 families) and family workers (N ¼ 46) completed the helpgiving practices scale and the enabling practices scale. Results: The FCA was largely present, parents rated its realization higher than family workers. Considering family workers' answers, parents' educational level appeared an important factor for parental autonomy. Conclusions: The study confirms recent research on the realization of the FCA. Including different perspectives, a nuanced view on the realization of the FCA was obtained. Further research on the concrete meaning, interpretation, and elaboration of the FCA is needed.

The aim of this study was to develop a coding scheme that enables researchers and practitioners to conduct a detailed analysis of the communicative behavior of young children with significant cognitive and motor developmental delays. Currently, there is a paucity of methods to do conduct such an analysis. For the study, video observations of three different scenarios from 38 children with significant cognitive and motor developmental delays aged between 12 and 54 months, were used. Findings from the video observations served as the primary means for development of the coding scheme, which comprises three main categories -- context, partner behavior, and individual behavior -- and several subcategories. The coding scheme was used to document the early expressive communicative behavior of persons with significant cognitive and motor developmental delays in a detailed manner. This fine-grained information is necessary to differentiate children based on their communicative abilities, to monitor their communicative development longitudinally, and to inform person-centered communicative interventions.

Background: Within the context of the Special Interest Research Group (SIRG) on Persons with Profound Intellectual and Multiple Disabilities (PIMD), researchers often discuss the methodological problems and challenges they are confronted with. The aim of the current article was to give an overview of these challenges. Methods: The challenges are centred on six topics. These reflect the main components of a study's design: (a) participant demarcation, (b) participant recruitment, (c) data collection and instruments, (d) data analysis, (e) ethics/including the "voice" of persons with PIMD and (f) theoretical models. Results: Next, to describing the specific challenges, possible solutions and pathways to address them are discussed. These are illustrated by recent studies by the authors and other researchers in the field. Conclusions: The current contribution wants to stimulate further discussion and exchange of ideas, and the development of creative research techniques.

Background: Professionals play an important role in supporting the social relations of persons with a disability. This study looks at professional practices supporting or strengthening social relations of persons in independent supported living, by integrating the perspectives of adults with a disability, network members and professionals. Method: Fifty-one semi-structured interviews were carried out. Results: Identified practices were: facilitating social situations, connecting with current and new network members, getting to know the person with a disability really well, delivering person-directed work, being a sounding board, being a safety net, working with an empowering attitude, seeing and exploiting opportunities. Influencing factors were related to the person with a disability, the professional, the network members and the broader environment. Conclusion: Identified practices were small actions rather than structured or programmatic interventions. An unique combination and complex interplay of factors was found within each case, where negative factors could be counterbalanced by positive factors.

Purpose: Key word signing (KWS) entails using manual signs to support the natural speech of individuals with normal hearing and who have communication difficulties. While manual signs from the local sign language may be used for this purpose, some KWS systems have opted for a distinct KWS lexicon. Distinct KWS lexicon typically aims for higher sign iconicity or recognizability to make the lexicon more accessible for individuals with intellectual disabilities. We sought to determine if, in the Belgian Dutch context, signs from such a distinct KWS lexicon (Spreken Met Ondersteuning van Gebaren [Speaking With Support of Signs; SMOG]) were indeed more iconic than their Flemish Sign Language (FSL) counterparts. Method: Participants were 224 adults with typical development who had no signing experience. They rated the resemblance between a FSL sign and its meaning. Raw data on the iconicity of SMOG from a previous study were used. Translucency was statistically and qualitatively compared between the SMOG lexicon and their FSL counterparts. Results: SMOG had an overall higher translucency than FSL and contained a higher number of iconic signs. Conclusion: This finding may support the value of a separate sign lexicon over using sign language signs. Nevertheless, other aspects, such as wide availability and inclusion, need to be considered.

Background: Children with a significant cognitive and motor developmental delay are pre-symbolic communicators. The primary aim of this study was to reveal the variability within the communicative functioning of this group of children in terms of communication level, the reasons to communicate and behavioural expressions. Methods: Twenty-six children between 14 and 58 months with a significant cognitive and motor developmental delay were recruited. The Communication Matrix of Rowland (2011, "Communication Disorders Quarterly," 32, 190) was used to integrate different sources of information on the children's communicative functioning. Results: These children primarily communicated at the level of pre-intentional and intentional behaviour, aimed at refusing, obtaining and, to a lesser extent, social purposes. Conclusions: To develop or adapt early intervention strategies, and to monitor progress in communicative development, an even more nuanced view on these children's communicative utterances in terms of frequency, duration, idiosyncrasy and context relatedness is needed.

Background: The increased life expectancy of people with intellectual disability intensifies the need for age-specific support. Research on effects of support strategies on quality of life (QoL) of these people remains scattered. Methods: A systematic search of peer-reviewed publications since 1995 was performed, with participants having intellectual disability and being aged =50 years. Studies include experimental, observational and exploratory designs, analysing links between support strategies and QoL outcomes. The present authors adopted a narrative approach. Results: The present authors found 73 articles, assessed their quality, thematically categorized interventions into 12 themes, and listed them with their stated relationships to QoL. Conclusions: The studies indicated the importance of funding, provision and organization of services/personnel, education, and cooperation among different support systems. The provision of good housing or activities, support when these provisions change, provision of (mental) health care, dementia care and end-of-life care, life story work, future planning and support for (I)ADLs are crucial.

Background: The hallmark of attachment is that contact, proximity and relief from stress are sought from specific individuals, laying important groundwork for healthy socioemotional functioning. This study investigated the extent to which differentiated attachment behaviour can be observed in young children with significant developmental delay (DD). Method: Video-taped observations of the parent-child and stranger-child interaction were conducted at home and complemented with questionnaires in 20 families with a child with significant DD (age 2-7 years with an average DD of 49 months). Results: Children displayed more intense and persistent contact-seeking, contact-maintaining and resistant behaviour in the episodes with their parent compared to the episodes with the stranger. Parent-reported secure attachment behaviour was slightly more characteristic towards mother compared to father. Conclusions: Even children with significant DD develop differentiated attachment behaviour. Detailed observations may support parents in identifying the interactions that make the attachment relationship with their child special.

Purpose: Key word signing (KWS) entails using manual signs to support the natural speech of individuals with normal hearing and who have communication difficulties. While manual signs from the local sign language may be used for this purpose, some KWS systems have opted for a distinct KWS lexicon. Distinct KWS lexicon typically aims for higher sign iconicity or recognizability to make the lexicon more accessible for individuals with intellectual disabilities. We sought to determine if, in the Belgian Dutch context, signs from such a distinct KWS lexicon (Spreken Met Ondersteuning van Gebaren [Speaking With Support of Signs; SMOG]) were indeed more iconic than their Flemish Sign Language (FSL) counterparts. Method: Participants were 224 adults with typical development who had no signing experience. They rated the resemblance between a FSL sign and its meaning. Raw data on the iconicity of SMOG from a previous study were used. Translucency was statistically and qualitatively compared between the SMOG lexicon and their FSL counterparts. Results: SMOG had an overall higher translucency than FSL and contained a higher number of iconic signs. Conclusion: This finding may support the value of a separate sign lexicon over using sign language signs. Nevertheless, other aspects, such as wide availability and inclusion, need to be considered., Individuals with intellectual disabilities often experience communication difficulties (Smith et al., 2020). By supporting their communication skills, augmentative and alternative communication (AAC) methods can facilitate their social participation (Beukelman & [...]

Background: In typical development, primarily contextual factors at the family level are clearly associated with child developmental outcomes. In contrast, knowledge about the contextual factors influencing the developmental characteristics of children (0-12 years) with severe to profound intellectual disability is scarce. Method: Through computerised searches of 4 bibliographic databases, 54 studies were identified. Results: The included studies were characterised by the use of small study populations and nonvalidated research instruments, as well as by strong research designs and detailed reporting of individual results. The majority of the studies evaluated procedures based on behaviourist learning theory, mostly aimed at reducing nonadaptive behaviour or stimulating choice behaviour. The studied factors proved to be generally effective. Conclusions: Family and parenting factors are one of the most striking gaps in the current literature about the development of children with intellectual disability. Also, further research on long-term developmental changes and bidirectional influences is necessary.

Current literature mainly focuses on adaptive profiles from a categorical perspective but yields inconclusive results. The present study puts a transdiagnostic approach next to a "classical" categorical approach. In this study, 222 children (5–18 years old) with autism and/or intellectual disability participated. Variance analyses, based on standard scores from ABAS-3 at group-level, were conducted in order to compare adaptive domains within categories. A K-Means cluster analysis was used to delineate empirically derived clusters with a similar profile of difference scores at an individual level. Chi-square tests and variance analyses were used to investigate the distribution of variables across clusters. From a categorical perspective, results were in line with current literature. A transdiagnostic perspective revealed three adaptive profiles (Homogeneous, Social, and Practical). No perfect match was found between specific adaptive profiles and diagnostic categories. A transdiagnostic perspective sheds light on the heterogeneity within and the overlap across diagnostic categories. [ABSTRACT FROM AUTHOR]

Background: Research findings suggest that direct support staff use augmentative and alternative communication (AAC) inconsistently. Various staff-related factors have been identified, and researchers agree that these factors somehow interrelate. Therefore, we approached AAC use as a behavioural process and examined the synergy between staff-related factors. Method: Fifteen direct support staff and 10 speech-language/occupational therapists who work with adults who have an intellectual disability and use AAC were individually interviewed. Transcripts were studied using thematic analysis. Results: Three main themes were discerned--consistent versus inconsistent AAC usage in direct support staff; time as a real and virtual barrier; friction in the peer-expert relationship. Conclusions: Direct support staff primarily used AAC when there was an acute need for communication support. In contrast, both direct support staff and speech-language therapists felt that direct support staff should consistently provide augmented input. This discrepancy was driven by team dynamics as well as actual and perceived lack of time.

Background: In spite of the profound cognitive and physical problems, people with profound intellectual and multiple disabilities (PIMD) are able to develop joint attention behaviours (JAB) and benefit from positive interactions. Aims: To investigate which context factors influence the JAB of people with PIMD. Method: Based on video recordings of 45 participants, JAB and context factors were analysed. Results: An unstructured interaction situation produced the most responses of a person with PIMD, whereas a structured interaction situation produced the most initiatives. Furthermore, the familiarity of the partner and the familiarity of objects used in the interaction had no influence on the JAB. The sensitivity of the interaction partner was positively related to the presence of JAB. Conclusions: Interaction partners of people with PIMD should be aware of both the ability of people with PIMD to use JAB and the influence of different context factors on these JAB.

Parents of children with severe disabilities have differing attachmentrelated support needs. An online vignette study with 25 experts, working in academia and/or clinical practice, was conducted to reflect upon the task of matching intervention components to families, based on their attachment strengths and needs. In two online rounds, the experts first completed an inventory of intervention (n = 25) components and second, they prioritised three components for particular families (n = 22). In addition, they reflected upon their argumentations for selecting these intervention components on different levels, either closely or more remotely connected to the children with disabilities themselves. The most common intervention choice across experts was to converse with parents to increase their understanding in the child's behaviours and communication. Experts justified their choices at various levels (child, parent, family unit, broader environment and professional). In that way, the current study provided an overview of the large number of elements that professionals and policy need to take into account when providing tailored intervention trajectories to these families. Systematically reflecting upon parents' attachment-related perceptions, strengths and (support) needs can furthermore stimulate professionals to prioritise their actions. It should, however, be embedded in a broader (diagnostic and contextual) intake procedure. [ABSTRACT FROM AUTHOR]

Purpose: Research has demonstrated that formal training is essential for professionals to learn key word signing. Yet, the particular didactic strategies have not been studied. Therefore, this study compared the effectiveness of verbal and video feedback in a key word signing training for future direct support staff. Method: Forty-nine future direct support staff were randomly assigned to 1 of 3 key word signing training programs: modeling and verbal feedback (classical method [CM]), additional video feedback ([superscript +]ViF), and additional video feedback and photo reminder ([superscript +]ViF/R). Signing accuracy and training acceptability were measured 1 week after and 7 months after training. Results: Participants from the [superscript +]ViF/R program achieved significantly higher signing accuracy compared with the CM group. Acceptability ratings did not differ between any of the groups. Conclusion: Results suggest that at an equal time investment, the programs containing more training components were more effective. Research on the effect of rehearsal on signing maintenance is warranted.

Background: A digital micro-intervention offering attachment psychoeducational videos was explored regarding its feasibility in parents of children with severe disabilities. Method: A mixed-methods study (including daily diaries and one-time questionnaires) with 16 parents (75.0% female) of children with severe disabilities (up to 10 years of age) was done during a three-week intervention. Results: Parents were positive about the video series and almost no drop-out occurred. The videos stimulated their learning and thinking and offered parents some personal meaning. Preliminary efficacy tests showed no major changes in parents' parenting self-efficacy (PSE) or perceptions of statements on parent–child attachment. Conclusions: The study showed promising results regarding the micro-interventions' acceptability and implementation. The limited efficacy testing did not show major changes in parents' PSE. Further research is needed to investigate the differential relevance of the micro-intervention, based on parents' needs, as well as its optimal embeddedness in a broader intervention trajectory. [ABSTRACT FROM AUTHOR]

The communicative behavior of young children with significant cognitive and motor developmental delays is generally considered to be limited, idiosyncratic and non-intentional. At present, changes between and within children over time regarding their communicative behavior are hard to detect. This article describes an exploratory observational study that draws on data from the first data point of 38 children who are participating in a longitudinal project on the developmental trajectories of children with significant cognitive and motor developmental delays. The aims of this study were to (a) describe the participants' communicative behavior in detail with communication-related variables that reflect differences across individuals, (b) create summarizing variables and (c) explore whether subgroups of children can be detected. A self-developed coding scheme and descriptive statistics combined with correlational analyses were used, followed by a principal component analysis and visual inspection of the outcome of this analysis. The within-group differences related to communicative behavior was characterized using 16 variables. Based on these variables, three overarching components were formulated: communication proficiency, Expressions of Discomfort and Rejection and Differentiation According to Focus. All participating children were found to be unique in terms of their component scores and the relationship among their component scores. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the influence of sign characteristics in a key word signing (KWS) system on the functional use of those signs by adults with intellectual disability (ID). Method: All 507 signs from a Flemish KWS system were characterized in terms of phonological, iconic, and referential characteristics. Phonological and referential characteristics were assigned to the signs by speech-language pathologists. The iconicity (i.e., transparency, guessing the meaning of the sign; and translucency, rating on a 6-point scale) of the signs were tested in 467 students. Sign functionality was studied in 119 adults with ID (mean mental age of 50.54 months) by means of a questionnaire, filled out by a support worker. Results: A generalized linear model with a negative binomial distribution (with log-link) showed that semantic category was the factor with the strongest influence on sign functionality, with grammatical class, referential concreteness, and translucency also playing a part. No sign phonological characteristics were found to be of significant influence on sign use. Conclusion: The meaning of a sign is the most important factor regarding its functionality (i.e., whether a sign is used in everyday communication). Phonological characteristics seem only of minor importance.