Studies of the sleep

"The Sleep Disorders Unit is accredited by the Spanish Committee for Accreditation in Sleep Medicine, endorsing our quality standards".


La Unidad del Sueño ha sido reconocida por la Sociedad Española del Sueño.

The studies of the sleep are destined to know the structure of the dream (insomnia, diurnal hypersomnia, fragmented dream) and the presence of abnormal phenomena, like they can be apneas (stops of breathing), abnormal movements, somnambulism or others.

With these studies, we will know the distribution of phases 1, 2, 3, 4 and REM, the duration of sleep, and the presence of peculiar episodes. The most common types are polysomnography, multiple latency test, actigrafia and pulse oximetry.

These tests require the patient to spend 1-2 nights in the hospital as it is necessary to record the activity during normal sleep hours.

The Sleep Unit of the Clínica Universidad de Navarra is accredited by the Spanish Committee of Sleep Medicine.

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When is a sleep study performed?

The purpose of sleep studies is to diagnose sleep abnormalities that may be directly or indirectly responsible for both nighttime sleep problems and daytime complications.

In fact, it is spoken of disomnias and not only of hyper or insomnias, since many times, the people who sleep badly during the night can present/display abnormal diurnal somnolence.

Most frequent indications of this test:

  • Hypersomnia.
  • Insomnia.
  • Narcolepsy.
  • Obstructive sleep apnea syndrome.

Do you have any of these diseases?

You may need to have a sleep study

Types of sleep studies

For polysomnography, sensors of the different body functions are placed to help determine what sleep looks like and if there are abnormal phenomena.

Depending on the symptoms and suspected diseases, some electrodes will be used or others.

There are studies of different types, since some can be directed only to record electroencephalography during a night, while others, the usual polysomnography, will be directed to record the maximum possible body values during sleep, including in addition to electroencephalography, eye movement, breathing movements, oxygen saturation, nasal flow, leg movements at least.

Polysomnography is performed in the hospital. It is recorded during one night, and can be repeated with treatment (CPAP) if the diagnosis of sleep apneas is confirmed.

In spite of the wires, it is usually achieved a sufficient sleep that gives an idea of the structure and if there are abnormal phenomena or not. There are systems of recording on paper, but have already been abandoned by more modern systems of recording on tape or computer. After recording, the computer performs an automatic analysis, which is then corrected by the sleep specialist.

On the screen, sleep events are reviewed, apneas or other phenomena are seen and the staging of the various phases of sleep is performed. It is necessary to review the 8-10 hours of sleep, which remains, despite progress, a long procedure.

It consists of the study of sleep entry latency and REM phase entry latency. For this purpose, the patient is made to sleep in 5 naps separated by 2 hours, during one day.

With this test it is possible to know whether or not there is abnormal hypersomnolence and whether it is a specific disease such as narcolepsy. It should be performed in cases of excessive daytime sleepiness, to check the latency of entry into sleep, and REM phase and to diagnose narcolepsy.

The electrodes are placed first thing in the morning. Usually it is enough to place some of the electrodes of encephalogram, stuck with collodion, the electrodes around the eyes (electrooculogram), and conveniently, EMG in chin and leg.

The patient is instructed to sleep every two hours, for 20 minutes. The physician checks the record by measuring the time until the patient falls asleep and whether he or she enters REM phase (sleep phase).

A latency of less than 5 minutes and two or more entries into REM phase are indicative of narcolepsy.

They are similar to those of the EEG. It is convenient to take the hair clean and to know if you have allergies to the materials that are going to be used. Some patients are overwhelmed by the sight of so many wires and no freedom of movement.

The doctor must understand and reassure the patient. It is rarely necessary to cancel the test for this reason.

It is recommended that patients take their usual medications, except in the case of suspected narcolepsy. In these cases, medication should be discontinued at least one week before the multiple latency test is performed (and it is preferable that there be several).

Where do we do it?


The Sleep Unit
of the Clínica Universidad de Navarra

Accredited by the Spanish Sleep Society, the Clinic's Sleep Unit has the latest advances in diagnosis and treatment of sleep disorders.

The joint work of the different medical and surgical disciplines that integrate the Unit of the Sleep of the Clinica does that every patient can be attended approaching his problem of global form, collaborating, if it is necessary, for different specialists.

Diseases we treat

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Why at the Clinica?

  • We have the best facilities to perform sleep studies.
  • Nursing specialized in these disorders for their care and follow up.
  • State-of-the-art technology and a highly specialized team.

Our team of professionals