Long time polysomnographic sleep and breathing evaluations in children with CDKL5 deficiency disorder.

Study Objectives: CDKL5 deficiency disorder (CDD) is a rare developmental and epileptic encephalopathy, developing in the first months of life, caused by a mutation in the cyclin-dependent kinase-like 5 (CDKL5) gene. Children with CDD often have sleep (90%) and breathing disorders in wake (50%). Sleep disorders may have a significant impact emotional wellbeing and quality of life of caregivers of children with CDD and are challenging to treat. The outcomes of these features are unknown in children with CDD.

Methods: We retrospectively evaluated sleep and respiratory function changes over 5-10 years in a small cohort of Dutch children with CDD, using video-EEG and/or polysomnography (3 × 24 h) and a parental questionnaire, the Sleep Disturbance Scale for Children (SDSC). The present study is a follow-up sleep and PSG study to evaluate if sleep and breathing disturbances persist in children with CDD previously studied.

Results: Sleep disturbances persisted during the study period (5.5-10 years). All five individuals had long sleep latency (SL, range 32-174.5 min) and frequent arousals and awakenings (14-50/night), unrelated to apneas/seizures, corresponding to the SDSC findings. Low sleep efficiency (SE, 41-80%) was present and did not improve. In our participants, total sleep time (TST, 3h52min-7h52min) was short and remained so. Time in bed (TIB) was typical for children aged 2-8 years, but did not adjust with ageing. Low duration (4.8-17.4%) or even absent REM sleep persisted over time. No sleep apneas were noted. Central apneas due to episodic hyperventilation were reported during wakefulness in two of the five.

Conclusion: Sleep disturbances were present and persisted in all. The decreased REM sleep and sporadic breathing disturbances in wake may indicate failure of brainstem nuclei. Sleep disturbances can severely affect the emotional wellbeing and quality of life of the caregivers and the individuals with CDD and are challenging to treat. Hopefully our polysomnographic sleep data contribute to find the optimal treatment of the sleep problems in CDD patients.