A sleep study, or polysomnogram (pol ee SOM no gram), is a test that measures and records several things that happen during a child’s sleep. What is measured depends on the kind of sleep problems your child is having. This test helps us to determine the quality of sleep of the child, whether the child has any breathing problem or apnea during sleep and what can be the possible cause of this sleep disturbance. This test helps us to determine the quality of sleep of the child, whether the child has any breathing problem or apnea during sleep and what can be the possible cause of this sleep disturbance.

What to expect in your child’s Sleep study

Child is taken to a sleeping unit or a room and explained about the test. The sleep techinician makes the child comfortable in the room by checking the temperature and provides blankets etc. Parents are advised to carry the child’s sleepy toys (if any), pillows, blankets so that the child feels more comfortable. Child is not sedated in this study. Several small areas of your child’s scalp, face, chest and legs are prepared for the test by gently rubbing with a ear bud and mild cleanser. Small round discs, called electrodes, are then attached to the scalp using gauze squares and glue. Sensor belts are strapped around child’s chest and abdomen. These belts are adjustable are not tight. The wires of the electrodes and sensors are connected to a box which can be easily detached from the main machine in case the child wants to use the bathroom at night. Usually children sleep well with these electrodes. The body sensors are put on so that the child can turn and move around during the night. Children probably don’t even know the sensors are on after wearing them for a short time. A battery of parameters are monitored with the use of sensors and electrodes that are strapped on to the child’s body. The electrodes do not hurt the child. The following parameters are measured overnight in a complete polysomnogram.

• Breathing – sensors are placed near the mouth and nose to measure the flow of air. Small elastic belts are put around the chest and waist to track when the child breathes in and out.
• O2 (oxygen) saturation – a sensor is put on a finger or toe to check oxygen levels
• ETCO2 monitor – a sensor is placed near the nose to measure the amount of carbon dioxide when the child breathes out.
• For an EEG these electrode discs are put on the scalp to measure brain activity.
• For an ECG the disks are put on the chest to measure the heartbeats.
• Eye movements – electrodes are put above and below the eyes
• Muscle movements – electrodes are put on the chin.
• Limb movements – electrodes are put on the legs or arms

In some children, only a cardiorespiratory polysomnogram is done in which the eye, muscle and limb movements are not recorded. Audio and video recording of the entire study is done with a camera and a microphone. After the child wakes up in the morning the electrodes and sensors are removed and the child is sent home. The glue used to stick the electrodes is easily removed by normal shampoo.

Reporting a polysomnogram

A polysomnogram tracing from the study is given to the pediatric pulmonologist who then analyses the overnight study and marks episodes of hypopneas (decreased breathing effort during sleep) and apneas (complete cessation of breathing) during the study. These hypopneas and apneas are then counted and a apnea-hypopnea index is calculated that tells us about the severity of sleep related breathing disorder. Pediatric seep studies must be analysed by a pediatric pulmonologist to reduce errors on diagnosis.