Actigraphy – Detecting Sleep-Wake Rhythm Disorders
Actigraphy is a diagnostic, non-invasive procedure used to record periods of activity and rest over an extended time. In sleep medicine, it allows us to analyze a person’s sleep-wake rhythm and detect potential sleep disorders. The test is performed using a wrist-worn movement sensor (actigraph), which looks like a watch and is small enough not to restrict movement.
Sleep-Wake Rhythm Disorder – Definition
The sleep-wake rhythm describes the natural alternation between sleep and wake phases within 24 hours. It is controlled by the human body’s internal clock, which is influenced by light, hormones, and biological processes. When this rhythm becomes disrupted, we speak of a sleep-wake rhythm disorder. This includes any mismatch between sleep and waking times and natural or social demands, often showing up as difficulties falling or staying asleep, irregular sleep times, or daytime tiredness and poor concentration.
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Common Questions About Sleep-Wake Rhythm Disorders
What types of sleep-wake rhythm disorders exist?
Sleep-wake rhythm disorders include a range of conditions in which the natural rhythm is disturbed. These include delayed sleep phase syndrome, where sufferers fall asleep very late and wake up late, and advanced sleep phase syndrome, where people fall asleep and wake up very early. Also included are irregular sleep-wake patterns, where sleep is broken up into several segments across the day, or rhythms not aligned to 24 hours, which are particularly common in people who are blind.
How can I restore my sleep-wake rhythm?
We recommend keeping consistent bedtimes and wake times, getting plenty of daylight in the morning, and avoiding disruptive influences in the evening such as screens or caffeine. In some cases, specific measures such as light therapy or melatonin supplements may be appropriate under medical supervision. Actigraphy supports this process by showing how the rhythm changes over days and weeks and whether improvements occur.
How are sleep-wake disorders treated?
Treatment always depends on the cause. Often the first step is improving sleep hygiene, meaning a better sleep environment and healthier habits. Light therapy may be added to help reset the internal clock. If needed, medication such as melatonin can support the natural sleep-wake process. Psychotherapeutic approaches such as cognitive behavioral therapy can also be useful, especially if stress or anxiety are contributing factors.
What happens if sleep disorders are not treated?
At first, untreated sleep-wake rhythm disorders show up as daytime fatigue, irritability, poor concentration, and reduced performance. Over time, however, the risk of serious conditions increases, including cardiovascular disease, metabolic problems such as diabetes, and mental health issues like depression and anxiety. Many sufferers also develop chronic exhaustion, which significantly lowers their quality of life. That is why it is important to act early and restore the rhythm with medical support.
Applications of Actigraphy
Actigraphy records physical activity and is therefore used in many medical fields. In sleep medicine, it is a key tool for analyzing the sleep-wake rhythm.
It is also widely used in chronobiology research, neurology, and psychiatry, where experts gain insights into the daily lives of different groups and conditions such as depression, dementia, or ADHD. Doctors also use actigraphy to monitor treatment progress and check whether interventions are working and sleep quality is improving.
How Does Actigraphy Work?
Inside the wrist-worn actigraph is a small motion sensor. It continuously records movement intensity, for example every 30 seconds, over a defined period. This makes it possible to determine whether you are walking, sitting, or sleeping. Later, experts evaluate the data and assess the duration and quality of rest and activity phases, showing when sleep starts, how long it lasts, and whether the sleep-wake rhythm is disrupted. Some actigraphs have additional sensors that collect more detailed information.
Benefits of Actigraphy
The small, lightweight actigraph is worn like a watch and does not interfere with everyday life. At the same time, it provides precise, non-invasive analysis of the sleep-wake rhythm and delivers objective data. This is a major advantage compared to many other methods for assessing symptoms of rhythm disorders, which often rely on the patient’s own perception and can therefore be inaccurate.
Because it can be worn for days or weeks, the actigraph records reliable sleep and activity patterns that are not distorted by short-term changes. This data forms not only the basis for diagnosis but also provides valuable insights into the effectiveness of treatment, making the actigraph a versatile tool in sleep medicine.
The Process of an Actigraphy Test
Actigraphy is a simple, stress-free test that measures the sleep-wake rhythm and uncovers symptoms of rhythm disorders.
During the introduction, we show you how the device works and answer any questions. You then wear the actigraph on your wrist for one to two weeks while going about your usual daily activities. If needed, you may also keep a sleep diary to record your personal perception of sleep.
When the recording period is finished, we evaluate the collected data and check for irregularities or indications of a rhythm disorder. We then discuss the results with you and, if treatment is needed, develop a therapy plan to restore your sleep-wake rhythm.
If you suspect you may suffer from a sleep-wake rhythm disorder, actigraphy offers quick, simple, and precise clarity. Book your test today and let us work together to restore your sleep quality.
Team of Experts
PD Dr. med. Marie-An Carstensen De Letter
Specialist in Neurology FMH / Neurophysiology / Sleep Medicine
Besire Morina
COO Sleep lab
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