Language in young children with neurofibromatosis-1: Relations to functional communication, attention, and social functioning

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Highlights

  • We examine language, attention, and functional communication in children with NF1.

  • As a group, children with NF1 show an elevated rate of language difficulties.

  • Children with NF1 show difficulties in specific areas of language.

  • Language problems were related to real-world social and communication difficulties.

  • Attention difficulties were not clearly related to language problems.

Abstract

In this study, the language abilities of 30 children with Neurofibromatosis Type 1 (NF1) aged 4–6 years were examined using a standardized measure of language. Relations of language to multiple parental report measures of functional communication, social skills, and attention problems were investigated. Difficulties in core language skills were observed, and more than 1/3 of the children struggled on at least one language index. Language abilities were significantly related to parental report of functional communication, social interaction and communication, and social skills, such that language difficulties may be a risk factor for communication and social interaction challenges and communication-related adaptive behavior in children with NF1. Though receptive language abilities were an area of particular difficulty for many children with NF1, they were not significantly related to parental ratings of social functioning and functional communication. Few significant relations were found between language and parent-reported attention problems, although some trends were noted. Hence attention difficulties in children with NF1 may contribute to, but do not appear to fully account for, language difficulties. In sum, there is an increased risk of language difficulties for young children with NF1, and lab-measured language difficulties appear to relate to everyday communication and social interaction functioning.

Introduction

Neurofibromatosis type 1 (NF1) is a genetic neurodevelopmental disorder present in about 1 in 3000 individuals. The disorder results from a single gene mutation in the neurofibromin 1 gene (17q11.2) which codes for the production of neurofibromin and in turn helps to regulate neuronal cell growth and development and suppress tumors. Without proper production of this gene, plexiform, cutaneous, or subcutaneous fibromas, or tumors, which characterize NF1, may form. Other physical traits include skeletal irregularities, café-au-lait spots, and axillary freckling (Ferner et al., 2007). Individuals with NF1 are at elevated risk for numerous cognitive and behavioral difficulties starting in early childhood. Notably, the average intellectual functioning of children with NF1 falls only slightly lower than that of unaffected children (Dilts et al., 1996, Eliason, 1986, Mazzocco et al., 1995, North et al., 1994, North et al., 2002), but children with NF1 often show deficits in one or more cognitive domains. Almost half of children with NF1 present with comorbid difficulties, including ADHD or subclinical attention difficulties, learning problems, executive function challenges, fine and gross motor difficulties, weaknesses in academic competence (particularly reading), visuomotor and visuospatial problems, and adaptive behavior deficits (Barton and North, 2004, Dilts et al., 1996, Hyman et al., 2005, Klein Tasman et al., 2013). Language problems have also been documented in individuals with NF1 (Dilts et al., 1996, Hyman et al., 2005, Lorenzo et al., 2011, Mazzocco et al., 1995, Thompson et al., 2010). These difficulties culminate in academic difficulties for youth with NF1 in comparison to unaffected peers. Although exploring the cognitive profile of children with NF1 has been the focus of a number of studies, there have been few studies of language problems specifically. Greater understanding of the language functioning of young children with NF1 is important for these individuals’ later success, as early identification of learning vulnerabilities is central to early intervention to maximize functioning.

Research with individuals without NF1 suggests that language difficulties and attention difficulties may be related (Gut et al., 2012, Helland et al., 2012), with several studies showing direct significant associations between the two in child populations (Bellani et al., 2011, Geurts and Embrechts, 2008, Haak et al., 2012, McGrath et al., 2008, Sowerby et al., 2011, Wassenberg et al., 2010). Specifically, deficits in language structure, semantic language, receptive language, expressive language, verbal working memory, and language comprehension have been associated with ADHD, as have interpersonal difficulties such as communication problems, difficulty understanding social cues, and trouble with pragmatics (Geurts and Embrechts, 2008, Gremillion and Martel, 2012, Gut et al., 2012, Haak et al., 2012, Helland et al., 2012, Sowerby et al., 2011, Wassenberg et al., 2010). Additionally, ADHD has been found to raise a child's risk of difficulty with social functioning (which heavily depends on language), with high rates of peer relationship difficulties in children with (Barton & North, 2004) and without NF1 (Guevremont & Dumas, 1994). Academic underachievement appears to be highly intertwined with these difficulties as well (Gremillion and Martel, 2012, Gut et al., 2012, Wassenberg et al., 2010); the ability to devote appropriate attention to a task is a crucial classroom skill, and difficulty in this area may very well be associated with language problems, interfering with the ability to understand material presented in an academic setting.

The association between language difficulties and attention problems is quite relevant to research involving children with NF1, as one of the hallmark features of the disorder is the high vulnerability to attention problems. Comorbid attention difficulties are often seen in children with NF1; strikingly, ADHD has been reported in 40–50% of cases (Eliason, 1986, Hyman et al., 2006, Koth et al., 2000), making it one of the most common difficulties for this population. ADHD occurs at a much higher rate in children with NF1 (42%) than in unaffected siblings (16%), and ADHD often presents in children whose parents show no signs of attention difficulties (Koth et al., 2000). Even in children without an ADHD diagnosis, those with NF1 still show significantly more hyperactivity and inattention compared to controls (Huijbregts, Swaab, & de Sonneville, 2010), with inattentive symptoms being particularly characteristic, even in young children (Sangster, Shores, Watt, & North, 2011). In fact, some level of attention difficulty is found in so many cases that Koth and colleagues (2000) suggest attention difficulties are a component of the NF1 phenotype. Klein-Tasman and colleagues (2014) found that verbal skills assessed broadly in the context of cognitive assessment were significantly related to attention and social skills difficulties. However, to date there is no research investigating relations between attention problems and comprehensively measured language functioning in young children with NF1.

There is some evidence that language difficulties are indeed present for an elevated proportion of school-aged children with NF1. Several studies have included examination of verbal functioning within the context of broad assessment, documenting mild difficulties with verbal functioning compared to siblings and same-aged peers (Billingsley et al., 2003, Brewer and Moore, 1997, Cutting and Levine, 2010, Eldridge et al., 1989, Hyman et al., 2005, Mazzocco et al., 1995, North et al., 1994, North et al., 1995, Sangster et al., 2011), although some of these differences were not significant after controlling for intellectual functioning (Hyman et al., 2005, Sangster et al., 2011). Closer examinations of language skills in school-aged children have revealed difficulties with broad expressive and receptive language skills as well as phonological awareness (Dilts et al., 1996, Mazzocco et al., 1995, North et al., 1994, North et al., 1995), but more in-depth research on the structure and content of language in individuals with NF1 is limited.

For young children with NF1, there is currently sparse information about language functioning. Some research on language within the context of broad cognitive and behavioral assessment suggests that very early language difficulties may be detectable in this population. In one case, while children (39 toddlers, aged 21–30 months) with NF1 did not show significant language difficulties in comparison to the normative mean, the majority exhibited below-average expressive language skills according to parental report (Lorenzo et al., 2011). Notably, Thompson and colleagues (2010) formally and comprehensively assessed expressive and receptive language in 19 preschoolers with NF1 with a standardized individually-administered language measure, the Clinical Evaluation of Language Fundamentals-Preschool, 2nd edition (CELF-P2; Wiig, Secord, & Semel, 2004). A substantial proportion of the participants demonstrated delays despite group scores in the low average range overall. Difficulties (defined as mean group performance more than 1 standard deviation below the mean) were detected on all expressive and receptive subtests, providing a more in-depth look than prior work at the nature of language difficulties. Some limitations of this study, however, include a small sample size, lack of inclusion of examination of the Language Content and Language Structure indices (which capture semantics and word/sentence structure), and lack of descriptive statistics at the subtest level beyond frequency of difficulty.

Characterizing the nature of language difficulties in young children with NF1 is important because, firstly, early language difficulties are argued to be strong predictors of problem behavior and learning difficulties in children without NF1. For example, expressive and/or receptive language problems in kindergarten have been associated with conduct problems, behavioral difficulties, hyperactivity, and social and academic problems later in elementary school (Bashir and Scavuzzo, 1992, Catts, 1993, Hooper et al., 2003, Sigafoos, 2000). In addition, verbal problems may be related to social, communicative and adaptive problems in children with NF1. Functional communication, which is a child's ability to seek out and communicate information in real-world situations (Reynolds & Kamphaus, 2004), and social skills have both been shown to be significantly poorer in children with NF1 compared to unaffected children and the normative population (Barton and North, 2004, Klein Tasman et al., 2013). Verbal skills also appear to be related to social skills and adaptive skills, including functional communication, when assessed in the context of cognitive functioning (Barton and North, 2004, Klein-Tasman et al., 2014).1

Further investigation of the interplay between expressive and receptive language abilities and everyday functioning is needed, as language problems may present psychosocial barriers and interfere with interactive functioning and learning within family, school, and community settings. There is especially a need for continued research about language abilities in young children with NF1, as language develops rapidly during these years and language difficulties are a risk factor for reading challenges in the general population. Many of these difficulties appear to be interrelated, and measuring a child's functional communication or social-communicative adaptive skills may reveal much about the impact of language difficulties on everyday functioning. A closer look at connections between language and language-related adaptive and behavioral problems is warranted given research suggesting relations between parental reports of real-world functional communication and lab-assessed verbal functioning in both children with NF1 and unaffected children. The purpose of the current study is to comprehensively examine language abilities in young children with NF1 and to investigate relations to functional communication, attention problems, and social functioning.

First, we aim to examine language abilities of children with NF1 for early signs of language difficulties in comparison to normative data. We will replicate and extend prior work (Thompson et al., 2010) by including a larger sample, examining composites not included in prior work (Language Content and Language Structure) and providing more detail regarding subtest-level performance. Second, we will expand on prior work by examining correspondence between lab-based measures of language functioning and parental ratings of functional communication, social difficulties, social-communicative adaptive skills, and attention problems commonly reported for children with NF1.

It is hypothesized that children with NF1 will exhibit difficulties compared to the normative population on CELF-P2 composite scores and subtests. While children with NF1 may exhibit mean composite scores within the average range on the CELF-P2, it is expected that the frequency of language difficulties in children with NF1 will be elevated. It is also hypothesized that language abilities as measured by the CELF-P2 will be significantly related to parental reports of functional communication, social functioning, and social-communicative adaptive behavior. Further, attention difficulties are expected to be related to the language abilities of children with NF1, as attention is important for comprehension and processing of oral and visual information.

Section snippets

Participants

Participants were 30 children with NF1 (20 males, 10 females), ranging from 4 to 6 years of age (M = 4.57, SD = .62). They were recruited from neurofibromatosis clinics in the Midwest for the medical management of NF1, as part of a larger longitudinal study investigating cognitive and behavioral characteristics of children with NF1 and their siblings, and were diagnosed with NF1 by specialized physicians based on NIH Consensus Conference criteria (NIH, 1988).

This study is from Year 2 of a

Results

SPSS version 20 and R version 2.15.0 were used to analyze data for this study. To control for multiple comparisons, a p-value of .01 was used; because of the small sample size, trend findings at p < .05 are also reported. Assumptions of normality were fulfilled for the vast majority of variables and relations. The pattern of results did not change based on the very few outliers identified. To represent what is believed to be the range of functioning in children with NF1, all scores were included

Discussion

This investigation of early language abilities in children with NF1 revealed weaker language skills in comparison to the normative population, with especially common difficulties related to receptive language and language structure. At the task level, particular difficulties understanding relationships between words and interpreting and following verbal directions were noted, and a large proportion of children showed language structure challenges. It is notable that there was good

Limitations, future directions, and conclusion

There are several limitations to the current study. First, although the sample is larger than in prior work about language functioning in preschoolers with NF1, it is nevertheless still small. Additionally, mean intellectual functioning was stronger than is generally present for children with NF1, such that this sample may represent a somewhat more cognitively capable group than is typical. Finally, in this study we relied on parental report of attention problems and social functioning, and it

Acknowledgements

This research was supported by funds from the UWM Research Growth Initiative, University of Chicago CTSA (UL1 RR024999), NF MidAtlantic and NF Midwest. The authors would like to thank the participants and their families for their valuable contribution to the research. The authors would also like to thank all research personnel at the Child Neurodevelopment Research Lab at the University of Wisconsin-Milwaukee for their help with data collection, measure scoring, and data entry and management.

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