Investigation of Sleep Quality and Prevalence of Sleep-disordered Breathing in Children and Young People With Epilepsy

Obstructive sleep apnoea (OSA) is a condition that affects around one in 20 children. In OSA, the muscles and soft tissues in the throat relax and collapse during sleep causing the upper airway to become blocked. Breathing is briefly interrupted, blood oxygen levels fall and this causes the child to wake and start breathing again. These episodes can happen many times a night causing severely disturbed sleep. Untreated OSA may leave children with daytime attention difficulties and problems with learning and behaviour. Epilepsy affects approximately 60,000 children in the UK and up to 30 per cent of these children have associated learning problems.

There is evidence, including pilot work undertaken by the study team to suggest that OSA is more common in children with epilepsy, in which case, sleep disturbance could account for some of the learning problems they experience. The aim of this study is to determine the prevalence of OSA in children with epilepsy.

The investigators plan to carry out detailed polysomnography sleep studies in 55 children with epilepsy and 28 healthy children (controls). These studies will measure the length and quality of sleep over one night spent at the hospital. Seizure activity during this period will be monitored by video recordings combined with electroencephalograms (EEG). Sleep-disordered will be assessed using a variety of tests to measure air-flow, lung expansion and blood oxygen levels. This study should help to determine if children with epilepsy are more likely to have OSA than healthy children of the same age. OSA is almost always treatable and the benefits of detecting and treating the condition in healthy children are well-established.

If OSA proves to be a common finding in children with epilepsy, it will be important to carry out further studies to see if treating the condition has beneficial effects on learning and behaviour. This project could lead doctors to target sleep-disordered breathing as a way of improving learning outcomes in children with epilepsy.

Children with epilepsy attending Royal Hospital for Children, Edinburgh will be invited to take part in the study. Children without epilepsy (controls) will also be recruited. The children without epilepsy are included because although there are statistics for incidence of OSA in the general population, information for all the measures of sleep the team will collect are not available.

The study will assess sleep time, sleep efficiency, sleep architecture and respiratory events in children with epilepsy and control subjects.

To be sufficiently powered, it is planned to test 50 children with epilepsy and 25 healthy controls.

A sleep physiologist will work with participants to measure:

• Polysomnography (to record body functions in sleep - airflow in and out of the lungs, oxygen level in the blood, body position, breathing effort and rate, electrical activity of muscles, eye movement and heart rate)
• EEG or electroencephalography (to measure the electrical activity of the brain),
• Electrooculography (to measure rapid eye movements along horizontal and vertical axes),
• Chin electromyogram (to measure electrical impulses to chin muscles),
• Sleep quality.

A neurologist and physiologist will assess seizure frequency and discharges between seizures, and epilepsy types using video EEG monitoring. Further information will be collected: height, weight, body mass index, antiepileptic medication use, tonsillar size, Mallampati score (a measure of base of tongue to hard palate), completion of sleep questionnaires by participants and their parents, to include sleepiness scales and sleep quality index.

Inclusion criteria

• Diagnosis of primary epilepsy and attendance at Epilepsy clinic

Exclusion criteria

• Neurological co-morbidity affecting muscle tone OR any Respiratory co-morbidity including any history of asthma, airborne allergy or sleep-disordered breathing.