Instrumentation & Measurement Magazine 24-6 - 82

lack of movement) [53]. Wi-Fi has also been used in vital signs
monitoring and basic activity recognition including the distinction
of speed in a study examining running, walking and
sitting speeds [53]-[55].
Summary
Table 1 summarizes the ambient sensor types discussed and
the type of measurement they have been used to achieve. In the
context of an older adult population, UWB and Wi-Fi monitoring
are good options for ambient assessment of movement, as
they do not inherently pose any identification or privacy risks
like image-based monitoring does, are not subject to light conditions
like optical video cameras and are not confined to a
specific surface like stationary pressure sensors [53]. They are
generally lower cost, have high range resolution, low power
requirements and can even be mobile; recent work has seen the
development of miniature radar for smartphone applications
[45]. Despite the clear advantages of UWB and Wi-Fi in ambient
monitoring, there are several challenges to address and
significant progress to be made before widespread implementation
can be achieved [44].
Ambient Sensing for Action
Motor-cognitive interactions involve the planning and production
of an action [17]. Where movement can be defined as
the displacement of body parts through space, action can be
thought of as the collection of movements required for a goaloriented
activity [17]. Action can be considered a higher order
function that requires more cognitive processing than does
movement. Measuring movement is necessary in the assessment
of ADLs, which, in turn, is instrumental in monitoring
cognitive decline [56]. Where unimodal data collection may
be able detect movement, multimodal data collection is often
used for measurements of ADLS as these actions usually
take up more physical space, involve several subject orientations
and are therefore more complicated to capture accurately.
The use of unimodal and multimodal sensor systems (in conjunction
with data processing) are explored in the context
of assessing activity within and outside of the home. Additionally,
the use of ambient sensing in cognitive training and
consequent cognitive improvement is examined.
Ambient Sensing at Home
ADLs are routine activities performed daily without assistance.
Basic ADLs include personal care and feeding oneself,
while Instrumental ADLs are more complex and include activities
required around the house, for example cooking or
cleaning. Ambient sensing has been useful in assessing ADLs
as well as in injury prevention. Electrical device usage has been
monitored using a non-intrusive load monitoring system,
where the classification accuracy (for electrical device identification)
was 86% [57], [58]. This technology proved useful in
Measured Entity
Table 1 - Summary of sensor types and applications in measuring movement
Applications in
Sensor Type
Pressure
* Capacitive
* Resistive
* Piezoelectric
* Piezoresistive
Force
* Photoelectronic
* Piezoresistive
* Capacitive sensors
Image-Based Sensing
* Optical light video
* Structured light
* Thermal infrared video
Radio Frequency
* UWB
* WiFi
* Radar
Temperature
Sound
82
* Thermal infrared video
* Temperature sensors
* Ultrasound
Measuring Movement
* Gait recognition
* Gait assessment
* Gait impairments
* Transfers
* Body sway
* Posture
* Gait recognition
* Gait assessment
* Skin shear
* Gait recognition
* Gait assessment
* Gait impairments
* Transfers
* Gait recognition
* Gait assessment
* Transfers
* Body sway
* Activity level
* Activity type
* Gait analysis
* Posture
* Ulcer risk
* Transfers
IEEE Instrumentation & Measurement Magazine
Relevant References
[21]-[27], [47]-[51]
[21], [28]-[32]
[21], [33]-[39]
[40]-[45], [53]-[55]
[46], [47]
[52]
September 2021
Instrumentation & Measurement Magazine 24-6

Table of Contents for the Digital Edition of Instrumentation & Measurement Magazine 24-6
