Lars Sonckin kaari 14, FI-02600 Espoo, Finland, +358 10 2190 610, [email protected] – Vivago.com
In their ground-breaking work in 2003, Ancoli-Israel et al. (1) concluded that information obtained by actigraphy is reliable for evaluating the sleep patterns and circadian rhythms, as well as the effects of treatments. Actigraphy provides information obtainable in no other way, especially in individuals who are less likely to tolerate polysomnography (PSG), which is the gold standard for sleep assessment, and used widely in sleep labs. The full text is available here.
Sadeh et al (2) have produced a review article, which brings the previous one from 2002 up to date. They conclude that actigraphy is sensitive in detecting unique sleep patterns associated with specific sleep disorders as well as with other medical or neurobehavioral disorders. The correlation between actigraphy and PSG is highest in healthy subjects that don’t have sleep disorders. The correlation is lower with insomniacs, where actigraphy typically overestimates the duration of sleep. Furthermore, actigraphy is sensitive in detecting sleep changes associated with drug treatments and non-pharmacologic interventions. The full text is available here.
Mayo Clinic published evidence-based recommendations for the use of actigraphy in the clinical setting, for various patient populations (3). This is a guide to the appropriate use of actigraphy, both as a diagnostic tool in the evaluation of sleep disorders and as an outcome measure of treatment efficacy in clinical settings. One of the conclusions is that actigraphy is indicated for characterizing sleep and circadian patterns and to document treatment responses in older adults (including older nursing home residents), in whom traditional sleep monitoring can be difficult.
The American Academy of Sleep Medicine (AASM) have published a comparative study on actigraphy versus PSG in subjects with sleep disordered breathing (4). It was concluded that actigraphy is not identical with PSG recording but gives good results in sleep/wake patterns and predicting several sleep parameters also in sleep apnea patients not suffering from other sleep disorders.
The necessary duration of sleep changes little with age, but sleep becomes lighter, fragmented, and diverse in quality. Also the likelihood of sleeping disorders increases: even 40 to 70% of the elderly are known to suffer from them at least occasionally. As the ability to maintain a stable circadian rhythm weakens with age, measuring circadian rhythms may give an implication of changes in the patients’ health status. The physiological processes of ageing relate to the suprachiasmatic nucleus (SCN), also called the biological clock of the brain, where lack of input may accelerate de-activation of neurons involved in the generation of 24-h rhythm. The good news is that this process appears to be reversible: supplementation of stimuli that impinge on the SCN can re-activate these neurons and ameliorate disturbances in the sleep-wake rhythm. (1,2)
Sleeping problems are one of the factors that contribute to the start of institutional care. One the other hand, the circadian rhythm of the elderly tends to deteriorate in institutions, especially in environments with little daytime activity. (3,4) Actigraphy-measured poor sleep has been associated with worse physical function, although all the underlying mechanisms for this phenomenon are not entirely known (5). Also, in the demented elderly, the strength of the circadian rhythm has a strong relationship with the functional status and wellbeing (6). This raises the possibility that actively supporting the circadian rhythm of the elderly may lead to enhanced overall wellbeing and help keep many chronic health problems in balance.
Disturbed sleep has been shown to correlate with accidents in all age groups. An example from the senior population are nocturnal awakenings and wandering that correlate with hip fractures (7). A significant number of falls take place in the night time, usually when a person is on their way to the toilet. Using a real-time actigraph may help a nurse intervene when they see their patient is active during the night.
Maintaining healthy physical activity and circadian rhythm are essential to rehabilitation, and plenty of studies exist on the topic. Below is a concise introduction to a few themes and studies that are relevant from actigraphy’s point of view.
In the rehabilitation of the elderly, daytime sleeping, i.e. weak circadian rhythm, has been recognized as a hindrance to functional recovery (1). Also rehabilitation after hip fracture has been studied (2), and higher daytime activity of the patients was shown to correlate with the prognosis of recovery. Actigraphy was proposed as a means of quantifying the activity.
Patients that suffer from Traumatic Brain Injury (TBI) often report sleeping problems and fatigue. A study by Sinclair et al. (3) included injured and healthy subjects, whose sleep and activity were followed by means of sleep diary and actigraphy. It was found that in the TBI patients, the agreement between self-reported and actigraphically monitored sleep information was weaker. Therefore, actigraphy was suggested as a potential follow-up tool for patients suffering from traumatic brain injury.
What comes to stroke patients, an interesting approach to follow up rehabilitation was suggested by Reiterer et al. (4), who used two actigraphs at both wrists of post-stroke patients to monitor their motor activity. The measurements were taken four times during a 6-month period after stroke. A significant positive correlation was found between the actigraphically recorded motor activity and the results of the Scandinavian Stroke scale, the Barthel Index, the Rankin Scale Score and with the Motoricity Index during the 1st week, which corresponds to the time when neurological deficits were most pronounced. The researchers suggest that actigraphy is a useful tool in the objective evaluation of motor activity after stroke. Moreover, actigraphy covers additional aspects that are not reflected by the usual stroke scales in a clinical situation.
Pain affects the circadian rhythm, and can be seen in the actigraph, both as poor sleep and a peculiar shape of the curve. Little scientific evidence exists of this relationship, though. This work has looked at advanced cancer patients and found that interventions improving the rest/activity rhythms may help improve the management of pain.
Even though scientific evidence on the use of actigraphy in pain management is scarce, plenty of empirical experience exists. Good pain medication helps patients sleep better, which has a direct effect on the circadian rhythm and the general quality of life. Measuring the changes in circadian rhythm may help the clinician choose and adjust the appropriate medication and other treatment of painful patients.
Actigraphy may be a useful tool to monitor the circadian rhythm of depressed patients, but not enough scientific work has been done to verify this. Below is an article with depressed outpatients (1). The writers noticed marked disturbances in sleep and circadian rest-activity rhythms in the study population. They suggest MESOR and fragmented sleep as predictors of depression, and also promote actigraphy as a potential aid in diagnosing depression.
One study (2) was done with 1215 non-depressed first year interns to see how sleep deprivation and high stress would affect their mood and precision in work. Actigraphy data were collected at baseline, and later at 3 and 6 months into internship. The study concluded that depression rates were highest among interns with both sleep disturbance and short sleep. Elevated medical error rates were reported by physicians sleeping ≤6 hr per night, working ≥ 70 weekly hours, and who were acutely or chronically depressed.
Changes in sleep, daytime activity and circadian rhythm are known factors in bipolar syndrome, and also a quite widely researched phenomenon. Actigraphy has been used surprisingly little in the diagnosis and treatment of bipolar syndrome, and further studies on the topic are warranted.
Depression, dementia, and physiologic changes contribute to the high prevalence of sleep disturbances in patients with Parkinson's disease (PD). Antiparkinsonian drugs also play a role in insomnia by increasing daytime sleepiness and affecting motor symptoms and depression. Polysomnography or actigraphy may be indicated.
The value of actigraphy in detecting bradykinesia, dyskinesia and tremor, and to help in the timely administration of antiparkinsonian drugs are suggested topics for future research.
Lars Sonckin kaari 14, FI-02600 Espoo, Finland, +358 10 2190 610, [email protected] – Vivago.com