INTRODUCTION:
Human locomotor activity could be recorded using the Actiwatch, which is operative through Actiwre host software. The Actiwatch device uses an accelerometer to detect and log wrist movement. This method is known as actigraphy and has been shown to be a useful means for discriminating sleep from wake activity. An objective recording is accomplished within the patient’s normal living environment for multiple, consecutive 24-hour periods. The small size (similar to a wrist-watch) and rugged nature of the Actiwatch allow it to be comfortably worn during activities of daily living, including bathing, swimming and even vigorous movement.
Once activity data are retrieved using the Actiware host software and communication dock, they are displayed as an actogram which is an insightful graphical display of sleep/wake patterns. This display allows for quick and easy interpretation and confirmation of sleep schedule and is a useful tool to help sleep professionals accurately educate patients about their sleep patterns. It also helps to identify the steps to achieve sleep improvement or benefits achieved. For in-depth analysis, individual sleep periods can be selected for interpretation via software algorithms to quantify sleep statistics.
The Actiwatch device can contribute to the assessment, therapy and follow-up of patients with a variety of sleep complaints. The American Academy of Sleep Medicine (AASM) has made various recommendations in its practice parameters for actigraphy in the study of sleep and circadian rhythms (Ancoli et al, 2003). These practice parameters are a guide to the appropriate use of actigraphy, both as a diagnostic tool for the evaluation of sleep disorders and as an outcome measure of treatment efficacy in clinical settings with appropriate sleep populations. Actigraphy can contribute to the diagnosis of insomnia assessment. Actigraphy is useful as an adjunct to routine clinical evaluation for diagnosis of circadian rhythm disorders and excessive sleepiness.
The usefulness of Actiwatch is maximized when demonstration of a multi-day rest-activity pattern is necessary, objective information about rest-activity patterns is needed or severity of sleep disturbances reported by the subject or caretaker is inconsistent with clinical impressions or laboratory findings. It is also helpful when clarification is needed of effects or compliance with pharmacologic, behavioral, phototherapeutic or chronotherapeutic treatment and even for collection of history cannot be obtained and polysomnographic study is not indicated or will not be of benefit. Actigraphy provides an alternative for daytime sleepiness information when it is not practical to administer the multiple sleep latency tests (Sadeh et al, 1995).
Actigraphy may be used effectively in the special populations like elderly, newborns, patients with hypertension, depression and schizophrenia. Actigraphy may also be useful in determining rest-activity patterns during portable sleep apnea testing.
METHODOLOGY:
The study was conducted on 20 subjects, attending a workshop, of various age groups ranging from 20-60 years. The system was installed on the subjects and the settings of devices were done directly to the subjects by strapping them on wrists. The work had been done by the help of computer experts, who installed the watches to the computer using Actiware software. The subjects were instructed how to treat it and wear the device properly. A log book was maintained to register each Actiwatch device, which consist all the required information of the subjects like, name, age, sex, medication, special physiological conditions and to record any significant developments or notes about the subject’s experience.
The Actiwatch devices were worn for 7 days in order to obtain a representative sample of sleep/wake behaviors. The subjects were instructed to maintain more or less similar routine. As all of the subjects were attending the same workshop, they were bound to maintain similar routine, which include:
Breakfast: 08:00 – 09:00
Session I: 10:00 – 13:00
Tea break: 11:30 – 11:45
Lunch: 13:00 – 14:00
Session II: 15:00 – 18:00
Tea break: 16:30 – 16:45
Presentation: 18:30 – 19:30
Dinner: 20:30 – 21:30
The subject details were uploaded in the computer and sampling information was set to the Actiwatch system. The Actiware software and Actiwatch was installed as per the Software Install Guides, the Actiware Software Manual. After 7 days, the Actiwatch devices along with the log book were returned for data processing.
After getting back, the data were retrieved from Actiwatches. This process placed the stored activity information from the Actiwatch into the patient database in computer within the Actiware Sleep Analysis Software for interpretation and analysis. The task was performed according to the Technician’s and Software Install Guides, the Actiware Software manual.
For every subject, the bedtime and rise time was set for each major sleep period (Rest Interval). Those data were entered from the event marker of the subject and sleep log. The time was also cross checked with the activity pattern. After initial configuration of the software program, a report was generated automatically and printed.
RESULT:
The rest activity patterns and calculated sleep statistics were reviewed with the subjects to understand their sleep patterns and their locomotor activities. The locomotor activities of 20 subjects for 7 days were recorded and the actigraphy was done, which revealed a more or less similar pattern of activity, which might have resulted due to similarity in their daily routine. The sleep wake pattern in 20 subjects were observed and analyzed considering their similar routine and was found that the maximum average rest interval (RI) was 514.3 of subject 6 and minimum 380.7 of subject 19. The average rest interval of 20 subjects for 7 days was 457.6.
DISCUSSION:
Actigraphy has been used to study sleep/wake patterns for over 20 years. The advantage of actigraphy over traditional polysomnography (PSG) is that actigraphy can conveniently record continuously for 24-hours a day for days, weeks or even longer. The wrist actigraphy can usefully approximate sleep versus wake state during 24 hours and have noted that actigraphy has been used for monitoring insomnia, circadian sleep/wake disturbances, and periodic limb movement disorder. Actigraphs are devices generally placed on the wrist, although they can also be placed on the ankle or trunk, to record movement. Collected data are downloaded to a computer for display and analysis of activity/ inactivity that in turn can be further analyzed to estimate wake/sleep. The latter technology is based on the observation that there is less movement during sleep and more movement during wake (Sadeh et al, 1995).
Actigraphs today have movement detectors (e.g., accelerometers) and sufficient memory to record for up to several weeks. Movement is sampled several times per second and stored for later analysis. Computer programs are used to derive levels of activity/inactivity, rhythm parameters, such as amplitude or acrophase, and sleep/wake parameters such as total sleep time, percent of time spent asleep, total wake time, percent of time spent awake and number of awakenings (Ancoli et al, 2003).
Actigraphy is increasingly being used in clinical research involving individuals of various ages, who are of normal health or with a variety of health conditions, and in a number of different settings. In the majority of these studies, actigraphy was used to measure sleep and activity rhythms that might not otherwise be available using traditional (e.g., PSG) techniques. In a growing number of sleep intervention trials, actigraphy performed for multiple days and nights of testing was reported to show evidence of beneficial treatment effects. Actigraphy has also been used in studies involving otherwise healthy adults to demonstrate sedating effects of various medications and to show differences in sleep during periods of sleep deprivation, for example, among military aircraft personnel on long flights. In addition, several large studies have used actigraphy in community-based samples to demonstrate differences between individuals based on age, gender, ethnicity, depressed mood, and other characteristics.
In the present study, the human locomotor activity of 20 subjects were recorded and analysed, using Wrist Actiwatch aided with Actiware Host Software. The subjects were having no significant sleep disorder and had shown regular sleep wake pattern and rest interval. The daily routine for all the subjects were similar as they were attending a workshop and were bounded to follow the schedule decided by the workshop.
The actigraphy could be a useful tool in understanding the sleep pattern of patients having various sleep disorders. By analyzing the actigram, the efficiency of the therapy of a particular sleep disorder could be outlined during treatment. Objective feedback to patients is often a very valuable tool to improve sleep. The actogram is a representation of normal sleep/wake patterns. The sleep periods typically appear at a similar point in the day and are of similar length. By showing patients a change to a pattern similar to this one, it is possible to reinforce behaviors that are conducive to good sleep.
ACKNOWLEDGEMENT:
The author would like to thank the Second SERC School of Chronobiology and the convener Prof. A.K. Pati, under guidance of whom the work had been done. The author would also grateful to her colleagues, who help her to make the project successful.
REFERENCES:
1. Ancoli-Israel S, Cole R, Allessi C, et. al. The Role of Actigraphy in the Study of Sleep and Circadian Rhythms. Sleep 2003; 26(3): 342-92.
2. Sadeh A, Hauri PJ, Kripke DF, Lavie P. The Role of Actigraphy in the Evaluation of Sleep Disorders. Sleep 1995; 18(4):288-302.