Insomnia & Actigraphy Testing

Insomnia & Actigraphy Testing

MotionWatch 8

The inability to get to sleep or stay asleep is commonplace. It is now classified as either Chronic Insomnia Disorder, or as Short-Term Insomnia Disorder by the American Academy of Sleep Medicine. The prevalence is about 10% of the population for Chronic Insomnia and 30-35% of the population for Short-Term Insomnia.

The consequences of insomnia include a degraded quality of life, delayed recovery from acute illness episodes and increased healthcare utilization. Insomnia is an independent risk factor for major depression and hypertension.

In Chronic Insomnia Disorder there must be frequent and persistent difficulty initiating or maintaining sleep with distress and impairment to important daytime functioning at work, social events, study etc., despite adequate sleep opportunity in an environment conducive to sleep.

It can occur on its own, or in association with a mental disorder, medical condition or substance use. The disorder is only recognised when associated daytime sleepiness occurs at least 3 times per week, for at least 3 months.

There may be predisposing factors but there are usually precipitating events and other factors that perpetuate the condition. Problems at work, bereavement and divorce are examples of events that can give rise to insomnia, and pain or fear of domestic abuse, by way of examples, may perpetuate it.

For those who are dissatisfied with their sleep and who believe they may have Chronic Insomnia Disorder we offer the following screening service.

Actigraphy testing using MotionWatch 8, by Cambridge Neurotechnology Ltd, England. This Class 1 medical device has been validated against the gold standard diagnostic test of Polysomnography (PSG). The validation includes the following parameters: total sleep time, sleep latency, and sleep efficiency. It also provides a very useful sleep fragmentation index.

Actigraphy is commonly used to assist sleep specialists in the diagnosis of sleep disorders, and demonstrates clearly any night-to-night variability in both the quantity and quality of sleep.


MotionWatch 8 is a wrist-worn device that is to be used for 7 days, 24 hours per day. It is waterproof to 1m so can be used during swimming (for up to an hour), in the bath or shower. It incorporates a light sensor to measure the presence or absence of light and its intensity, in the range 0 to 64000 lux. This can be useful to assess if there is detrimental bright light exposure prior to sleep time. MotionWatch 8 also has an event button, which can be pressed to note an event. Typically the event button is used during the night if the patient has to get up to use the toilet, and both at lights out time, and wake up time. MotionWatch 8 weighs just 20g.

During the 7 x 24 hour study the patient is asked to complete an hourly daytime event log showing their intake of stimulants, such as tea or coffee, their intake of sedatives, such as alcohol, and their level of sleepiness according to the Karolinska Sleepiness Score. With the Karolinska Sleepiness score a number is assigned to a specific degree of sleepiness: 5 is neither sleepy nor alert, 1 is fully alert, and 9 is very sleepy with great effort needed to stay awake.

The combination of the objective actigraphy data, the diary and a general medical questionnaire, will enable a professional report to be compiled for you and your doctor that identifies the condition, and provides recommended treatment options. We always visually inspect and validated the data, noting in our reports any omissions and anomalies.

The actigraphy data is processed using MotionWare software that has specialist algorithms using Non-Parametric Circadian Rhythm Analysis (NPCRA). The data is moderated as necessary by a Registered Polysomnographic Technologist (RPSGT), who prepares the report.

We report on actual sleep time, and sleep latency in hours and minutes, and sleep efficiency in percentage terms. A sleep fragmentation index is also provided. These data points are given for each of the 7 nights and aggregated to provide a mean average for each parameter.

In suspected 'insufficient sleep syndrome' cases the actigraphy study will often have two phases. The first phase comprises a week of 24hr actigraphy and sleep diaries. The equipment is returned to us for data reading and initial analysis. If the first phase indicates 'insufficient sleep syndrome', the second phase, will comprise a further week of extended sleep time measured with actigraphy, supplemented with sleep diaries. A comprehensive report, prepared by a Registered Polysomnographic Technologist (RPSGT) is included in the fee.

MotionWatch 8 is extremely sensitive: it measures g-forces from 0.01 to 8. The frequency of movement is filtered outside the range 3 - 11g. This filtering excludes low frequency motion artifacts such as turning the wrist and high frequency artifacts resulting from cycle riding or driving a car.

MotionWatch 8 should not be mistaken for consumer electronic devices like fitness monitors that neither have the sensitivity nor the validated software to make their results admissible in a clinical setting.

Actigraphy is also often used to document treatment response, and we recommend a follow-up study after treatment.

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