Sleep disturbances and behavior in Smith-Magenis syndrome.

BACKGROUND: The Smith-Magenis syndrome (SMS) shows a collection of neurodevelopmental problems including mild to moderate intellectual disability, change-related anxiety, impulsivity, speech delay, Attention-Deficit/Hyperactivity Disorder (ADH) and sleep disturbances. Sleep disorders, when present, have been treated in several populations with consecutive improvements in cognitive and behavioral aspects. AIMS: To better understand the existing relationships between sleep disturbances and behavioral problems in SMS syndrome this study describes the sleep and behavior problems in the SMS and explores the possible relation between both. METHODS AND PROCEDURES: 17 individuals with SMS (50% males; 11.2 ± 4.9 years old) and 12 individuals with typical development (50% male; 11.1 ± 4.4 years old) were investigated using the Sleep Disturbance Scale for Children and the Child Behavior Checklist. RESULTS: A high percentage (60%) of individuals with SMS have an indication of sleep disorders, being the most frequent disorders the sleep-wake transition disorders, and disorders of initiating and maintaining sleep with sleep latency higher than acceptable and total sleep time below acceptable. More than 94% of the SMS group presented clinical or borderline scores on the total behavioral problems scale. The most common behavioral problems were Externalizing Problems, Thought and Attention, ADH and Aggressive problems. There was a positive correlation between disorders of initiating and maintaining sleep, sleep-wake transition disorders, disorders of arousal, disorders of excessive somnolence and behavioral problems. CONCLUSIONS AND IMPLICATIONS: The worse the sleep disturbances investigated, the more severe the behavioral problems characteristics reinforcing the importance to address the sleep problems in the treatment of SMS individuals.

Maternal Interactive Behaviours in Parenting Children with Williams Syndrome and Autism Spectrum Disorder: Relations with Emotional/Behavioural Problems.

This study compared maternal responsiveness to children with two neurodevelopmental disorders sharing different but, in some cases, overlapping social phenotypes-Williams syndrome (WS) and autism spectrum disorder (ASD)-and explored the relations between maternal responsiveness and child emotional/behavioural problems (EBP). The sample included 16 pre-schoolers with WS and 43 with ASD, and their mothers. Responsiveness was assessed during a mother-child interaction task. Mothers completed the CBCL 1½-5, providing a measure of EBP. No significant differences emerged between groups, and most dyads were characterized by less responsive behaviours. Maternal responsiveness proved related to child developmental age, but not with EBP. These results provide further insight into the rearing environment of children with neurodevelopmental disorders, highlighting the need for early relationship-based interventions.

Syntax in Spanish-speaking children with Williams syndrome.

The syntactic skills of Spanish-speaking children with Williams syndrome (WS) were assessed in different areas (phrase structure, recursion, and bound anaphora). Children were compared to typically-developing peers matched either in chronological age (CA-TD) or in verbal age (VA-TD). In all tasks children with WS performed significantly worse than CA-TD children, but similarly to VA-TD children. However, significant differences were observed in specific domains, particularly regarding sentences with cross-serial dependencies. At the same time, children with WS were less sensitive to syntactic constraints and exhibited a poorer knowledge of some functional words (specifically, of nonreflexive pronouns). A processing bottleneck or a computational constraint may account for this outcome.

Habilidades morfológicas de los niños con desarrollo típico y síndrome de Down / Morphological abilities of typically developing children and children with Down syndrome

En este trabajo se presentan los resultados de un experimento diseñado para ahondar en el conocimiento acerca de las habilidades morfológicas de los niños con desarrollo típico y de los niños con síndrome de Down. Para ello empleamos el test Wug y manipulamos el fonema final del estímulo, consonántico o vocálico, para generar plurales de seudopalabras. Los resultados señalan que los niños cometen más errores a la hora de formar plurales con el alomorfo -es que con el alomorfos, lo que evidencia una relación entre el procesamiento fonológico y la aplicación de la regla morfológica del plural -procesamiento morfológico-. Por otro lado, los niños con síndrome de Down cometen más errores que los niños de los 2 grupos control (grupo igualado por edad mental e igualado por nivel de vocabulario), lo que permite afirmar que la aplicación de esta regla morfológica de formación de plural está genuinamente alterada en estos niños y no es consecuencia ni de la capacidad intelectual ni del nivel de vocabulario (AU)

This article presents the results of an experiment designed to study the morphological abilities of typically developing children and those of children with Down syndrome. To do this, we used the Wug test and manipulated the final phoneme of the stimulus, consonant or vowel, to generate pseudoword plurals. The results indicated that children made more errors with the plural morpheme -es than with -s, suggesting a relationship between phonological processing and the application of the morphological rule. Children with Down syndrome made more errors than children from the 2 control groups (children matched by mental age and by vocabulary level), suggesting that the application of this rule is genuinely altered in these children and is not a result of their intellectual ability or vocabulary level (AU)

Differences on morphological and phonological processing between typically developing children and children with Down syndrome.

It is widely acknowledged that people with Down syndrome (Ds) have less highly developed morphosyntactic abilities than typically developing (TD) children. However, little is known about the morphological processing of this population. In this paper we carry out two experiments in which the morphological Base Frequency (BF) effect is explored in both groups. The aim of the experiments is to carry out an in-depth exploration of morphological processing in children with Ds and TD children. In the first experiment children performed a definition task; in the second children had to provide a plural form for singular words. The results show a significant BF effect in only the first experiment. In the second experiment this morphological variable does not reach significance, but the variable we called Ending phoneme (a phonological variable that refers to the last phoneme of the bases prior to the addition of plural morphemes) does. The results also show that children with Ds score significantly below the two control groups in both experiments, with no significant differences between control groups. We go on to discuss morphological processing in children with and without Ds, the role of the two tasks carried out (paying special attention to the role played by working memory), and the possible relationship between our results and morphosyntactic deficits described in the literature.

Cognitive functioning in children and adults with Smith-Magenis syndrome.

Smith-Magenis Syndrome (SMS) is a genetic neurodevelopmental disorder caused by a microdeletion on chromosome 17p11.2. This syndrome is characterized by a distinctive profile of physical, medical and neuropsychological characteristics. The latter include general mental disability, with the majority of individuals falling within the mild to moderate range. This study reports a detailed cognitive assessment of children and adults with SMS with the use of the Wechsler intelligence scales at three distinct levels of analysis: full scale IQ, factorial indices, and subtests. Child and adult samples were each compared to samples of age and gender-matched typically developing individuals. To our knowledge, this is the first study to systematically analyse the cognitive profile of individuals with SMS in Southern Europe. The present study confirmed mental disability, particularly within the moderate category, as a consistent feature of children and adults with SMS. Furthermore, both child and adult samples evidenced significant impairments in all four indices when compared with their typically developing counterparts. A specific pattern of strengths and weaknesses was discernible for both samples, with Verbal Comprehension emerging as a relative strength, whereas Working Memory appeared as a relative weakness. Finally, with the exception of two subtests in the perceptual domain, we found no evidence for a general cognitive decline with age.

How executive functions are related to intelligence in Williams syndrome.

Williams syndrome is characterized by impairments in executive functions (EFs). However, it remains unknown how distinct types of EFs relate to intelligence in this syndrome. The present study analyzed performance on working memory, inhibiting and shifting, and its links to IQ in a sample of 17 individuals with WS, and compared them with a group of 17 typically developing individuals matched on chronological age and gender. In conclusion, our results suggest that working memory, inhibiting, and shifting relate differently to intelligence in WS as well as in typical development, with working memory being the EF most closely related to intelligence in both groups. Notably, the magnitude of the associations between the three EFs and IQ was substantially higher in the WS group than in the TD group, bringing further confirmation to the notion that frontal lobe impairments may produce a general compromise of several EFs.

MRI amygdala volume in Williams Syndrome.

One of the most intriguing characteristics of Williams Syndrome individuals is their hypersociability. The amygdala has been consistently implicated in the etiology of this social profile, particularly given its role in emotional and social behavior. This study examined amygdala volume and symmetry in WS individuals and in age and sex matched controls. Magnetic resonance imaging scans were obtained on a GE 1.5-T magnet with 1.5-mm contiguous slices and were used to measure whole gray matter, white matter and cerebrospinal fluid volumes, as well as amygdala volume (right and left). Results revealed significantly reduced intracranial volume in individuals with WS, compared with controls. There were no differences between groups in absolute amygdalae volume, although there was a relative increase in amygdalae volumes, when adjusted for total intracranial content. There were no inter-hemispheric differences in amygdalae volumes in both groups. These results suggest a relative increase in amygdala volume in WS compared with healthy controls that likely reflects abnormal neurodevelopmental processes of midline brain structures.