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