Discussion
The results of this unique prospective nationwide cohort study of
children with a newly diagnosed brain tumor demonstrate a high
prevalence of sleep problems at brain tumor diagnosis, mostly reported
by parents of patients. Actigraphic sleep outcomes were not different
from those of healthy controls.
We found a high rate of parent reported child sleep disturbance and
sleep related impairment, with up to half of the parents reporting
moderate or severe problems. Children themselves frequently reported
severe sleep disturbances, especially more shortly after brain tumor
diagnosis. These findings are consistent with our expectations,
indicating sleep problems are experienced regularly and already at the
earliest phase of cancer treatment, possibly arising as a result of
factors such as distress and neurological damage. Interestingly, alhough
parents reported high rates of sleep related impairments, children did
not report this and on average these scores did not differ from the
general population.
Differences in self- and proxy-report are common in pediatric research
and may be explained by several factors29-31. Firstly,
children may underreport symptoms. This can be the result of “response
shift”, meaning symptoms are judged differently during cancer treatment
than how they would be judged before diagnosis32. It
could also be that neurocognitive-, stress- and sleep disturbances
impact children’s’ capability of adequately recalling sleep
experiences33. Second, parents may overreport symptoms
due to feelings of stress and concern. Earlier research suggests that
parental distress, parental sleep problems and parenting problems are
related to parent reported child sleep30. Hence,
differences in self- and proxy-reports emphasize the importance of using
both types when measuring sleep, as they are both informative and may
provide complementary information in this phase of treatment.
We hypothesized that actigraphic outcomes would show lower sleep
estimates compared to age-matched, healthy controls, due to the physical
and psychosocial stressors associated with the period following
pediatric brain tumor diagnosis. The absence of these findings is
largely consistent with earlier, similar research in patients with acute
lymphoblastic leukemia (ALL)30. However, children with
ALL did show longer sleeping times than healthy peers, possibly because
these children require more sleep, as they are ill and physically
recovering. It could therefore be argued that although the number of
minutes children with recently diagnosed brain tumors sleep is similar
to healthy children, they might have a higher need for sleep to support
optimal recovery34,35. Furthermore, this study sample
was almost entirely assessed during the Covid-19 pandemic, while data of
the control group was collected before. It is plausible that children
sleep better during the pandemic, as they were able to sleep longer due
to home schooling and were less exposed to stimuli during the
day36. In the healthy population, it was found that
people with insomnia complaints experienced clinically meaningful
alleviations of symptoms during the pandemic37.
Another factor that may influence sleep during the diagnostic period are
substantial efforts and strategies of parents, such as co-sleeping and
comforting activities, as illustrated in parents of children with
ALL38. Possibly, as parents put in a great deal of
energy, they do report sleep problems, and yet these efforts seem
relatively effective in terms of sleep duration.
Generally, little research has been done with actigraphy and children
with cancer during treatment. However, sleep problems are well described
and measured amongst brain tumor survivors11,39. Toxic
treatmens effects such as radiation therapy or endocrine disturbances
may lead to those sleep problems at a later stage. Longitudinal data
from this current study should provide more insight into this
matter11,40.
This study has several limitations. Although the participant group is
relatively large for pediatric brain tumor research, there may not have
been enough power to demonstrate specific predictors for sleep problems.
In addition, not all parents and children participated in all sleep
measurements, due to for example treatment toxicity or study burden,
increasing the risk of participation bias. Subsequently, even though
participants were recruited from a national pediatric oncology hospital,
specific tumor groups were underrepresented which may have lead to
selection bias. Twenty-four children with low grade brain tumors who
required neurosurgery only and had a favorable prognosis were primarily
treated in affiliated hospitals and therefore not participating in this
study. Twelve children with high grade tumors were not invited, as they
were receiving palliative care with high morbidity, and the treating
physician requested not to burden the family.
Actigraphy measures movement and is well validated, but does not measure
sleep phases (light, deep and REM sleep). Also, children may have
shifted circadian rhythms or inconsistent bedtimes, which is not
reflected in the actual number of minutes asleep, but may still contribe
to fatigue3,7,41. Future research should explore sleep
phases and rhythms to gain more insight into sleep quality. Lastly,
previous research suggests more knowledge of parents on sleep hygiene
benefits child sleep, suggesting education and support for parents may
be an efficient intervention42,43. Future research
should therefore consider collecting more comprehensive data on parents
and parenting strategies as well.
In conclusion, sleep problems in children with a brain tumor are
frequently reported in the first three months after brain tumor
diagnosis. Clinicians should be attentive to sleep problems, as it may
induce serious, negative consequences in this already vulnerable group.
Increasing our understanding of sleep is of major importance because
sleep is vital for recovery and health-related quality of life.
Conflict of Interest. The authors have no conflict of interest to
declare.
Acknowledgements. The authors would like to thank the
psycho-oncology and neuro-oncology teams for their contribution and
support.
Funding. This study was funded by The Princess Máxima Center for
Pediatric Oncology.