A polysomnogram (PSG) is a sleep study in which the patient is monitored for sleep abnormalities.
Typically, the patient will spend the night at a laboratory while keeping to their daily routine as closely as possible. Equipment is attached to the patient to monitor brain activity and the stages of sleep while Dr Alison Richardson monitors the patient's behaviour.
PSG is commonly used to diagnose conditions such as sleep apnea and other sleep disordered breathing. It can also be used to diagnose nocturnal seizures or spasms, periodic limb movements, sleepwalking, night terrors and rapid eye movement disorders.
The MSLT (Multiple Sleep Latency Test) is used to diagnose excessive daytime sleepiness by measuring how quickly an individual falls asleep in a quiet, dark environment during the day. The MSLT is also the standard tool used to determine whether or not an individual suffers from narcolepsy or idiopathic hypersomnia.
The MSLT consists of five scheduled naps that are separated by two-hour breaks. During each nap trial, the individual is placed in a dark room that has a comfortable bed which allows for the ideal sleep environment. Once the individual lies down, the test will measure how long it takes for them to fall asleep. A series of sensors will be used to measure whether the individual is sleeping, as well as to determine the stage of sleep. After 15 minutes, the individual will be awakened, however, if he or she does not fall asleep within 20 minutes, the nap trial will end.
Excessive daytime sleepiness occurs when you feel sleepy during times when you should be awake and alert. Dr Alison Richardson will recommend an MSLT if she suspects that you have excessive daytime sleepiness due to narcolepsy or hypersomnia. However, the results of the MSLT can be affected by a variety of factors, including anxiety, tension, depression, age, caffeine, drugs and medications, and the amount of sleep before the study.
For this reason, Dr Richardson recommends the following before your MSLT:
- Keep a sleep diary for two weeks. This allows Dr Richardson to see your sleep-wake patterns, and identify other factors that may be causing daytime sleepiness.
- Discuss the use of any stimulants - including caffeine - before your MSLT.
- Try to get at least six hours of sleep the night before the MSLT. This ensures that the results are accurate.
- In some cases, you may be required to take a drug test on the morning of the MSLT, as there are a number of drugs that can affect the results of the sleep study. The results of the drug test will be confidential.
24 hour EEG monitoring
An EEG - known as an electroencephalogram - is a noninvasive test that is used to record electrical patterns in the brain. The results of the test enabled Dr Alison Richardson to diagnose conditions such as seizures, epilepsy, head injuries, dizziness, headaches, brain tumours and sleeping problems. It can also be used to confirm when an individual is brain dead.
While abnormal brain activity can occur in both children and adults, the neonatal period is when seizures are most likely to start happening, especially if the infant is already in the intensive care unit with other conditions like encephalopathy (brain disease, damage or malfunction), prematurity or a brain injury from birth. Because of this, all newborns in ICU are monitored with 24-hour continuous EEG. With 24-hour EEG monitoring, Dr Richardson will watch and evaluate the brain activity of a newborn, around the clock. The monitoring will continue until the baby is stable.
The benefit of 24-hour EEG monitoring is that Dr Richardson watches the brain activity in real time, and can, therefore, take immediate action as soon as an abnormal result appears. Since the monitoring takes place in a medical practice, all the necessary treatment is immediately available. This ensures that better outcomes are possible in the event of a seizure.