Table 6.

Summary statements of the minimum standards for recording routine and sleep electroencephalography EEG

Indications of non-emergent EEG recorded by appointment include indications related to epilepsy, seizures, brain dysfunction and differential diagnosis as detailed in Table 2.

Technical standards are summarized in Table 3.

Duration of EEG: 20 minutes for the routine EEG and 30 minutes for the sleep EEG excluding preparation is suggested. It is advisable to book the sleep recording of infants and children in the postprandial period, where there is a higher chance to fall asleep. We suggest individualizing the recording time and duration when increased benefit is expected. Booking morning time for patients with suspected juvenile myoclonic epilepsy, prioritizing sleep recording in patients with suspected or diagnosed self-limited focal epilepsy of childhood or infantile epileptic spasms syndrome, and on suspicion of infantile epileptic spasms syndrome, extending recording at least 10 minutes after awakening to increase the probability of recording of epileptic spasms probably increase the yield of EEG.

Sleep-induction: Partial sleep deprivation is suggested as a primary method in adults and children 12 years of age or older who can cooperate to the sleep deprivation. An example of suggested partial sleep deprivation protocol is shown in Table 4. However, it is important to note that there are no studies evaluating the safety of partial or full sleep deprivation for any age group. Sleep deprivation may also cause significant distress to a child and family. Melatonin or sleep deprivation are suggested as a primary sleep induction method in children under 12 years of age. If sleep deprivation or melatonin fails to induce sleep, their combination may be more effective. Melatonin is proposed as a primary sleep induction method in children and adults who cannot cooperate to partial sleep deprivation. The suggested dose of melatonin is 1–3 mg administered 30–60 min before the start of the EEG recording. If melatonin is not available in the market, chloral hydrate may be used when partial sleep deprivation fails to attain sleep and patient safety is ensured.

Provocation methods: Hyperventilation, intermittent photic stimulation (IPS) including baseline recording of eyes open, and eyes closed are suggested unless contraindicated. Asking the patient to blink, close and open eyes for several seconds documents artifacts, permits evaluation of posterior dominant rhythm and is a provocative method for eye-closure sensitivity. It is proposed to use other simple stimulation methods, for example touch, sudden noises or reading aloud a difficult text, when they are known to provoke seizures. In adults, IPS is suggested to perform before hyperventilation at the beginning of EEG at least 3 minutes apart. However, if the referral diagnosis is genetic generalized epilepsy, it is advisable to do activations at the end of recording due to increased probability of seizures. IPS often raises level of vigilance and decreases probability of sleep and hyperventilation has an opposite effect. Therefore, in children, it is useful to perform hyperventilation at the beginning of sleep EEG and IPS at the end. The patient and caregiver should be informed in advance about the potential benefits as well as adverse effects of activations, particularly seizures and potential loss of driving permission. Information may also increase the occurrence of non-epileptic seizures. Patient has the right to know about the possibility to refuse activations. Hyperventilation and IPS protocols are detailed in Table 3. Contraindication for IPS: pregnancy Contraindications for hyperventilation are sickle cell disease or trait, Moya-Moya disease and syndrome, cerebrovascular malformations including aneurysms, cerebrovascular events in the last three months, raised intracranial pressure, myocardial infarction, cardiac arrhythmias and other severe forms of cardiac disorders, severe pulmonary disorders, and pregnancy. Preferably, list of contraindications is available for the referring physician to report existing contraindication. As a minimum and in cases of a time lag between referral and EEG, EEG technologist should inquire the patient about contraindications and document the answer. Responsibility of EEG technologist is to guarantee the patient safety and the quality of recording that necessitates continuous monitoring of one recording at a time. The patient should be under continuous surveillance during the recording. The EEG technologist should have possibility to call for help. During seizures, it is advisable to test the patient with a standardized method (Table 5).