活動腕表(actiwatch)是什麼？
活動腕表內有活動記錄器和光線監測器，會每隔一段時間(註2)就評估活動的強度和接受的光線強度。所以理論上在夜晚睡覺時，活動量和光線都會下降，等到低於設定的閾值時，分析軟體就會判定這個時間點應該是處於睡眠狀態，而醫師/技術員可以參考睡眠日誌作進一步的修正。
哪些情形需要使用
圖示說明
【和睡眠日誌的差異】
如果家長/病人自己寫的睡眠日誌可信度很高，的確是不需要另外多作這項檢查的；【和睡眠多項性生理檢查(polysomnography, PSG)的差異】
兩個檢查能診斷的疾病不同哦！ 睡眠多項性生理檢查主打對象是呼吸/動作障礙，例如呼吸中止症候群、肢體周期抖動症、不寧腿、快速動眼期動作障礙，而且只能評估一晚；而活動腕表則是針對長時間睡眠/活動狀態，所以比較適合針對失眠、日間嗜睡等病人。【與市售的智慧手錶或手環記錄睡眠功能有什麼不同】
活動腕表可以看到什麼？
- 就寢時間(bedtime)
- 起床時間(wake up Time)
- 躺在床上的時間(Time in Bed)
- 睡眠時間(Total sleep time)
- 入睡所需時間(sleep latency)
- 睡眠效率(sleep efficiency)
- 入睡後清醒時間長度 (wake after sleep onset)和次數(#awake)
所以您發現了嗎？它沒辦法像睡眠多項性生理檢查(PSG)告訴你為睡不好的原因哦！
使用上需注意事項
- 雖然有部分防水功能，但是洗澡或游泳等可能接觸大量水分的情況下請拿下儀器，以免損壞。
- 戴在非慣用手；有時候嬰幼兒會戴在腳踝上
- 正常活動下請盡量避免衣物遮住活動腕表：因為有光線監測器，如果常常被蓋住，在軟體分析時有時候會被誤判是在睡覺。
- 需要簡單記錄活動狀態，至少要包括就寢時間、起床時間和未配戴儀器的時間：這樣可幫助醫師更正確的分析結果。
- 最重要的是不要弄丟或損害儀器：目前各家醫院都會要求使用者簽損害賠償切結書。
結論
活動腕表目前仍是睡眠醫學中最可信的穿戴式儀器，但是如同本文所說它賴以分析的基礎僅有活動量和光線，然而目前市售許多類似產品能記錄的訊號更多，包括心律、血氧濃度，或許在作完信效度分析之後，可以期待未來能有更便宜更準確的分析儀器供大家使用。註
- 在2020年就筆者所知臺灣市場上有三家廠商提供這項產品。
- 數據收集的間隔時間至少是1分鐘1次以上。而市售商用穿戴式裝置很難達到這麼快的取樣速度，所以當然反應在售價上。
Many wearable devices now have sleep monitoring functions, and clinics often encounter parents who bring in recorded data on apps for consultation. However, can these devices really be applied to children? Or which of the recorded values are reliable? Which are unreliable? This really requires more research to confirm. Today we will introduce the longest-used wearable device in sleep medicine: the actiwatch (activity tracker).
Appearance and Principle
The appearance of the actiwatch may vary slightly depending on the manufacturer, but it generally looks like a watch. Brands with more functions may have a larger size and more buttons, but comfort will be compromised when worn (Note 1).
Inside the activity tracker are an activity recorder and a light sensor, which evaluate the intensity of activity and the strength of received light at regular intervals (Note 2). Therefore, in theory, during sleep at night, both activity and light should decrease. When they fall below the set threshold, the analysis software will determine that this time point is in a sleep state, and the doctor/technician can refer to the sleep diary for further adjustment.
When to Use
Because the activity tracker can record long-term activity status, it is often used clinically in the following two situations:
- To understand the day-night cycle changes: late sleep and late waking? Early sleep and early waking? Or an irregular schedule?
- In attempting to identify the cause of "feeling very sleepy during the day", such as narcolepsy/hypersomnia, which is characterized by long total sleep time, or sleep deprivation syndrome, which finds that the total sleep time at night is reduced.
Difference from Sleep Diary
If the sleep diary written by the parent/patient has a high level of credibility, there is no need for additional testing.
However, sometimes the child is lying in bed with their eyes closed, and the parent may think they are asleep. Or the child may already be awake and playing, but the parent may not know because they are in a different bed (room) or the parent is still asleep, which can lead to an incorrect estimation of the child's sleep duration. In this case, the activity tracker can evaluate whether the activity level at that time point is below the threshold, which provides a more objective evaluation.
Or if a teenager gets up to play on their phone in the middle of the night, they may not want to write it in their sleep diary! In this case, the activity tracker has a light sensor, which can detect changes in light and know that the child is not actually sleeping.
Difference from Polysomnography (PSG)
The two tests diagnose different diseases! Polysomnography mainly targets respiratory/movement disorders, such as sleep apnea syndrome, periodic limb movement disorder, etc.
It is important to note that while actiwatch can provide some information about a person's awake-sleep patterns, they can not provide more information as a full polysomnography test. Therefore, if a person has suspected sleep disorders, they should seek professional medical advice and undergo a full sleep study.
What can you see on an activity tracker?
Different brands of activity trackers may display different numbers, but they generally include the following: Bedtime ,Wake-up time ,Time spent in bed, Total sleep time
,Sleep latency (time it takes to fall asleep), Sleep efficiency, Wake after sleep onset (duration and frequency of awakenings)
The software will calculate the daily values and the average values during the time the tracker is worn. However, it is important to note that the tracker cannot tell you why you are not sleeping well, like a polysomnography (PSG) test can.
Usage notes:
- Although some models are waterproof, it is recommended to remove the tracker during activities such as bathing or swimming to avoid damage.
- Wear the tracker on your non-dominant hand; sometimes it can also be worn on a baby's ankle.
- Try to avoid clothing covering the tracker during normal activity, as the light sensor may be blocked and mistakenly interpreted as sleep.
- It is important to keep a simple record of your activity, including bedtime, wake-up time, and times when the tracker was not worn, to help doctors analyze the results accurately.
- Lastly, do not lose or damage the device as most hospitals require users to sign a disclaimer for any potential damage to the device.
In conclusion
