Validation of the Mobility Monitor for detecting mobility related activities

The percentage of elderly in our society grows in a relative as well as an
absolute fashion. In The Netherlands, the group of people aged 65 comprised 14%
of the population, and by 2040 this percentage will be 23%. In addition to
this, due to for instance the more advancing health care, the average age of
people keeps rising steadily. This trend enlarges the burden on health care
further because older people generally are in need of more chronic care and
monitoring, and that way the growing age problem accordingly brings on the
issue of shortage of doctors, nurses and other resources in health care.
Thus, efficiency in health care in financial respect as well as resources is
becoming a more and more relevant item in health research. Following from the
expected trends marked above, one of the major areas in which progression can
be accomplished is the area of chronic home-based care and monitoring for the
elderly and several chronic patient groups.
A recent development in this area is the Mobility Monitor, a necklace-worn tool
to measure activity, balance and power in detecting and monitoring postures and
walking. This device is aimed to function in detection of functional decline
and it's consequences in the elderly. It will also be used in activity
monitoring and stimulation programs, as previous research indicates that
physical activity has many beneficial effects on health and disease burden in
older people and other chronic patient groups.
At this moment, the Mobility Monitor is being tested on technical
characteristics. In this study, the technical validity (sensitivity and
specificity) of the Mobility Monitor for detecting postures
*sedentary* (sitting, lying) and *active* (standing and walking) in a
home-based setting with frail and non-frail older adults will be assessed, as
well as the user acceptability and practical feasibility of home monitoring
with the device.

The aim of this study is to determine the technical validity (sensitivity and
specificity) of the Mobility Monitor for detecting and monitoring postures and
walking in a home-based setting with frail and non-frail older adults. The
targeted sensitivity and specificity values for the different postures and
activities are > 90%. Secondary goals are to assess the practical feasibility
and the user acceptance of the method, both in the direct use of the mobility
monitor in the study and by means of a questionnaire filled in by the
participants. A third objective is to compare two subjective, self-report means
of past physical activity (the SQUASH and PASE questionnaires) and objective
measurement of physical activity with the Mobility Monitor.

The study will be an observational validation study of the prototype monitoring
device Mobility Monitor.
The measurements will take place in the subjects' home environment. The first
measurement contact will consist of filling out several questionnaires on
health status, fear of falling, and activities of daily living, and completing
a standardized movement protocol and free movement period wearing the sensor.
This meeting will last about 1,5 hours. The next part of the measurements will
be an independent week long measurement wearing the sensor in their regular
daily life. The last measurement contact will be to collect the sensor and
checking of several additional questionnaires, which will concern the user's
opinion about the device and his or her physical activity pattern during the
week measurements and had to be completed before this contact. This will last
about 15 minutes.

Subjects will be monitored during a fixed protocol and semi-free movement in
their home environment in one session while being simultaneously monitored by
both video and our neck-worn Mobility Monitor. Afterwards the person will wear
the monitor for a full week in daily life non-stop.
The two groups, frail and non-frail, will be regarded together, separately and
in comparison to each other on abovementioned calculations of sensitivity and
specificity of the device, as well as user acceptance and practical usability.
Is the device accurate and feasible in community-dwelling elderly, and are
these features better in frail or in non-frail older persons? From these
results, implications for further research and fine-tuning will be given.