Does Sleep Disturbance Cause Daytime Behavior Problems—or Vice Versa?


Sleep is a complex neurologic function, and being a consistent good sleeper requires a normally functioning nervous system. In the general population, multiple studies have indicated that children with sleep problems also exhibit an increase in problem behavior and psychiatric symptoms, along with a decrease in intellectual performance and short-term memory. Sleep difficulties are reported at a higher incidence among children with neurodevelopmental disabilities, with prevalence rates reaching as high as 80 percent. A few studies have shown similar results in families of children with Fragile X syndrome.

With their already compromised nervous systems and their families’ generally more stressed environment, children with FXS represent a host of complex interactions involving both biological and environmental factors. Getting a good night’s sleep may thus be a challenge not only for them, but for parents or siblings whose own sleep is affected by the child’s restlessness.

P1010005In an earlier study, 47 percent of parents of children with a full mutation of Fragile X syndrome (FXS) reported their children to have significant sleep problems (Kronk, Noll, Dahl, 2009). In a national survey, 32 percent of children with a full mutation (1,295 children) had reported sleep problems, consisting mainly of difficulty falling asleep, frequent night awakenings, and early morning waking as the most prevalent symptoms (Kronk, et al, 2010). Most children (82 percent) had two or more of these sleep problems. Also reported was an association between health and behavior problems and sleep.

Two years ago my colleagues and I at the Fragile X Center, , undertook a study to help determine whether an association exists between sleep and daytime behaviors in children with FXS. If we could find that it does, it may help lead to a wider choice of treatment options. This small study looked at such an association in 37 children with a full mutation (33 males/4 females), 8 children with a premutation (5 males/3 females), and 15 children in the grey zone (7 males/8 females). All children were between the ages of 3-16 years.

By responding to the Children’s Sleep Habits Questionnaire (CSHQ), parents reported that 70 percent of the children in this study had a clinical level of sleep problems. The parents also completed the Child Behavior Checklist (CBCL), a widely used measure focusing on a child’s social, emotional and behavioral performance that can be grouped into internalizing problems (e.g. anxiety or withdrawn behaviors) or externalizing behaviors (e.g. aggression, opposition, rule-breaking behaviors), out of which a total score is reported.

When comparing the two measures, CSHQ to CBCL, it was discovered that a strong association existed, meaning that those with sleep problems also had a significant number of daytime behavior problems. This occurred for both males and females and across all groups.

It was also important to evaluate not only daytime behaviors but the general functioning of these children as well. By parents completing an Adaptive Behavior Assessment System (ABAS-II) report, their child’s skills in social, practical, and conceptual areas were measured and compared again to the CSHQ. Not surprisingly, the adaptive scores for children with sleep problems were significantly lower.

Thirty-six of the children were able to wear a motion watch to bed that measured several aspects of sleep. Although not all children were able to tolerate wearing this device, the children who did were a mix of good and not-so-good sleepers.

What did we learn from the data reported by this watch? That sleep is quite varied.

Figure 1

Figure 1. Behaviors do not occur in isolation.

For the most part, children stayed in bed approximately six to almost 12 hours, but slept between 67 percent and 95 percent of the time they were in bed. For the lower (67 percent) end of that range, it makes for a long restless night in bed! To further illustrate this point, a review of the wake periods during the night revealed a range from 7.5 minutes to 1 hour and 37 minutes!

The good and bad news is that behaviors do not occur in isolation (figure 1). Higher levels of sleep disturbances, difficult daytime behaviors, and behaviors of lower functioning appear to be connected to one another. The good news about this is that since behaviors are not isolated, then as we treat one behavior it is reasonable to expect that the other behaviors may improve as well. The goal should always be to improve overall functioning and performance of the individual child.

Knowing that several paths can lead to achievement of that goal allows for individual treatment of each child and his or her circumstances. So whether we treat sleep or daytime behaviors first may not be the pertinent question.

    Figure 2. The key to success is treating the behavior of concern first — and then closely monitoring the interaction among all behavior

Figure 2. The key to success is treating the behavior of concern first — and then closely monitoring the interaction among all behavior

The key to success is treating the behavior of most concern first—and then closely monitoring the interaction among all behaviors (figure 2).

In all such studies, we can gauge measurable and incremental improvements by using parent report. The behavioral and functional measures used in this study also have teacher report versions, which can also serve as another source of information. The ultimate goal is that study by study, we will accumulate more knowledge that parents and clinicians will be able to draw upon in devising strategies to improve the sleep of children with Fragile X syndrome.

Becky Kronk, PhD, MSN, CRNPBecky Kronk, PhD, MSN, CRNP
is an assistant professor of nursing at Duquesne University and a clinical assistant professor at the Fragile X Center, Children’s Hospital of Pittsburgh. Email: or