UC Davis

Children with fragile X syndrome (FXS) have significant delays in many domains of functioning. Biological mothers of children with FXS are at an increased genetic risk for experiencing cognitive, physical, and mental health challenges. Parental mental health challenges and stress are often associated with reduced marital cohesion and satisfaction, which is likely to spill over and negatively affect the parent-child relationship for both mothers and fathers. Past research shows that parentally responsive behavior positively influences language development in both neurotypical children and children with intellectual and developmental disabilities, including those with FXS. However, the majority of past studies on parent-child interactions, and families of children with FXS more generally, have focused exclusively on the mother-child relationship. Therefore, very little is known about fathers in these families, including their well-being and their role in the child’s development. The current dissertation fills this gap by examining multiple features of the family environment, including the mother-father relationship, the mother-child relationship, and the father-child relationship in 23 families of children with FXS. Study 1 examined parental and couple well-being and associations between child functioning and these domains. Mothers and fathers independently completed questionnaires regarding their mental health, parenting stress, couples satisfaction, and dyadic coping in their relationship. Parents also independently completed questionnaires regarding their child’s challenging behaviors and symptoms of autism spectrum disorder (ASD). One parent also completed an interview about the child’s adaptive functioning. Results from this study indicated that mothers and fathers in these families experienced elevated levels of clinically significant mental health challenges and parenting stress compared to levels reported in the general population. However, despite these challenges, the majority of both mothers and fathers reported average to above average levels of couple well-being (i.e., couples satisfaction and dyadic coping). Multilevel models indicated that higher levels of parenting stress predicted lower levels of both couples satisfaction and dyadic coping. Additionally, multilevel models indicated that higher levels of child challenging behavior predicted higher levels of mental health challenges and parenting stress as well as lower levels of couples satisfaction and dyadic coping. Moreover, the parents of children with higher levels of adaptive functioning reported lower levels of parenting stress and higher levels of couples satisfaction. There were no significant differences in these relationships between mothers and fathers. Study 2 examined relationships among maternal responsivity, paternal responsivity, and parental and couple functioning. Mothers and fathers separately engaged in 12-minute dyadic play-based interactions with their child. These interactions were recorded via secure teleconferencing in the families’ homes. Recordings were transcribed and coded for the presence of parentally responsive behaviors and behavior management strategies. Results indicated significant correspondences between mothers’ and fathers’ frequencies and rates of responsive behaviors during the parent-child dyadic interactions. However, overall, mothers used comments more frequently than fathers, and fathers used a higher proportion of behavior management utterances compared to mothers. Multilevel models indicated that higher levels of parenting stress predicted lower rates of parental responsivity and higher rates of behavior management, but these effects were only marginally significant. Couples satisfaction did not predict either category of parent behavior. Study 3 examined relationships among maternal responsivity, paternal responsivity, and child language; it also examined relationships between child characteristics (i.e., challenging behavior, ASD symptoms, and adaptive behavior) and child language as well as parent behavior. Measures of parent and child language were obtained from the transcripts of the mother-child and father-child interactions. The measures were talkativeness, lexical diversity, and syntactic complexity. Multilevel models indicated that both maternal and paternal responsivity were positively associated with child talkativeness and lexical diversity. Parental responsivity, however, was not associated with child syntactic complexity. Findings also indicated that older children and children with higher levels of adaptive behavior had parents who used higher rates of responsive behaviors; these children also had higher levels of talkativeness, lexical diversity, and syntactic complexity. Additionally, fathers used higher rates of behavior management strategies compared to mothers, and this type of parental behavior was not associated with child language performance. The findings of this dissertation advance our understanding of family relationships in families of children with FXS as well as features of dyadic relationships within families that promote optimal outcomes.