Personalized cancer chronotherapeutics encourage 
the cell division cycle and the pharmacology 
pathways to improve patients’ quality of life and 
survival (Lévi, Filipski et al. 2007). Thus, the 
circadian rhythm needs to be explored on large scale, 
and circadian biomarkers should be calculated to 
estimate the incidence of cancer-associated circadian-
system alterations.   
The most effective parameter that can correlates 
with the quality of life is the dichotomy index (I<O) 
(Mormont, Waterhouse et al. 2000, Innominato, 
Focan et al. 2009, Natale, Innominato et al. 2015). 
This latter represents the percentage of the activity 
counts measured when the patient is in bed that are 
inferior to the median of the activity counts measured 
when the patient is out of bed. This index can 
theoretically vary between 0 and 100%, where high 
I<O reflects a marked rest/activity rhythm.   
In order to record rest-activity cycle, the majority 
of recent studies used wrist actigraphy; a wearable 
device used to measure the activity motors. On the 
other hand, various techniques were used to calculate 
the I<O. For instance, in Mormont, M. et al study, the 
calculation was done manually where each patient 
had kept a diary for times of rising and retiring during 
the diagnosis (Mormont, Waterhouse et al. 2000). 
Scrully, C. et al and Ortiz-Tudela, E. et al have used 
square and mean waveform techniques respectively 
which resulted as a poor biomarkers (Innominato, 
Focan et al. 2009, Ortiz-Tudela, Martinez-Nicolas et 
al. 2010). In Ortiz-Tudela, E. et al study, patients 
were requested to give  an informed consent and to 
complete a sleep and feeding log during the days of 
recording (Ortiz‐Tudela, Iurisci et al. 2014). Finally, 
some patients were demanded to push an event-
marker button on the wearable device to mark 
occurrences of time in and out of bed such as Natale, 
V. et al research (Natale, Innominato et al. 2015). 
In this study, we aim to detect the rest- activity 
cycle automatically and calculate the I<O while 
minimizing the intervention of patients and 
smoothing the interference of physicians. After data 
acquisition, I<O was calculated automatically based 
on DARC algorithm. Then, a graphical user interface 
(GUI) was performed to detect and calculate 
automatically rest-activity cycle and I<O.  
2 METHODOLOGY 
2.1 Database 
Our study is based on 9 control subjects (5 females 
and 4 males) aged 40 ± 10.6 years. After receiving a 
detailed description of the objectives and 
requirements of the study, the participants wore the 
infrared sensor “Movisens GmbH - move II”. The 
move II sensor consists of a tri-axial acceleration 
sensor (adxl345, Analog Devices; range: ±8 g; 
sampling rate: 64 Hz; resolution: 12 bit) and a 
temperature sensor (MLX90615 high resolution 
16bit ADC; resolution of 0.02°C). This sensor was 
patched onto  the participants’ upper right anterior 
thoracic areas by means of a hypoallergenic patch 
for a minimum of three consecutive days. It only 
weighs 32 g, and measures 5.0 x 3.6 x1.7 cm3. The 
recorded data is saved on a memory chip inside the 
sensor and transferred to a server via the General 
Packet Radio Service (GPRS). Three signals were 
available:  
  Zero Crossing Mode (ZCM) signal: 
representing the human activity in function of 
time, with 1 record per minute  
  Body Position: representing the human body 
slope with respect to the vertical x-axis, with 1 
record per minute  
  Body Temperature: representing the human 
body temperature, with 1 record every 5 
minutes  
2.2  Rest/Activity Cycle Detection 
In this study, the automatic detection of rest/activity 
cycle is achieved based on the “Détection 
Automatique du Rythme Circadien” (DARC) 
algorithm (Chkeir et al. 2017). Six phases summarize 
our work, and for confidential reasons, it will be 
discussed generally in a brief way.  
First, as we have one record of body temperature 
each 5 minutes and one record per minute for each of 
body position and ZCM signals, the Polynomial 
Cubic Spline method is used to interpolate the 
temperature signal, so we get an equal number of 
records between signals. The interpolated 
temperature signal intervenes as a reference to check 
if the sensor is worn or not. The algorithm will 
directly eliminate the body position and ZCM records 
when sensor is not worn. In case the sensor is worn 
upside down, the algorithm will correct the Body 
Position signal: when X is greater than 90, the value 
will be replaced by 180-X.  
Subsequently, all outlier points that could  
appear in the signals will be eliminated based on  
the median filter techniques. After that, the method 
cited in the DARC Brevet  automatically operates