Instrumentation & Measurement Magazine 25-6 - 7

[8]. The problem with this diagnosis is that the assigned scores
are highly subjective. It is therefore necessary to carry out instrumental
tests such as positron emission tomography to
identify pathological processes through a direct analysis of
the cells' functioning. Obviously, these analyses are expensive
and available only in specialized centers given the adopted
technologies. To monitor the motor symptoms of PD, a 3D
magnetic positioning system was proposed [9], [10]. This system
is partially invasive since the patient only needs to wear
a device, such as a sensorized glove; it is accurate and compatible
with the requirements of low cost and low energy
consumption.
Fig. 3. Obtained ECT map with the positioning system turned on.
Fig. 3. In this case, the map is less regular than in the previous
case, due to the fact that the ECP positions used to construct
the map were provided by the positioning system. These positions
are less accurate than those provided by the scanning
system although very low positioning errors are obtained; in
all the scanning points, errors range in [0.1, 2.0] mm compared
with 0.1 mm warranted by the scanning system. It is important
to note that even the less regular map provides a clear and precise
indication of the presence and the position of the defect on
the metal plate under investigation.
Finally, the obtained result validates the proposed solution
to provide the ECP position during the execution of an
ECT. This solution guarantees low-cost hardware and low
computational burden, and it is compliant with freehand test
execution.
Parkinson's Disease Monitoring
Parkinson's disease (PD) is a neurodegenerative disease that
manifests itself in patients through motor and non-motor
symptoms. The main motor symptoms are tremor, rigidity
and bradykinesia. To date, during a specialist visit, the neurologist
asks the patient to perform specific tasks; based on
the patient's response, the neurologist assigns a score to each
task on the basis of a Unified Parkinson's Disease Rating Scale
The positioning system consists of 24 rx coils operating as
anchors and a tx coil operating as a tag. The choice of the number
and arrangements of the anchors has been investigated in
[11]. Both the rx and tx coils are connected in parallel to a suitable
capacitor to obtain a resonance condition. The resonant
frequency common to all coils is about 182 kHz. Compared
to the adopted set-up for the NDT application, the change in
the resonant frequency is due to the different characteristics in
terms of size and number of windings of the used coils. These
constructive updates have allowed an optimization of the coils
which has led to a different resonant frequency of the two systems.
The tag is powered with a square wave signal through
a Cypress PSoC 5LP MCU. The induced voltages on the anchors
were amplified through an Analog Devices AD8421
instrumentation amplifier and acquired through a dedicated
data acquisition system. To experimentally validate the proposed
methodology, it was necessary to emulate the motor
symptoms of Parkinson's through repeatable movements.
To do this, a robotic arm was used to impose known trajectories
to the tag while a servo motor was useful to superimpose
the typical Parkinsonian tremor on the trajectories. An Arduino
UNO R3 microcontroller unit was used to control the
servo motor. The use of a robotic arm and a servo motor warrants
faithful movement reproduction, allowing it to remotely
control the trajectory and therefore accurately impose parameters,
such as frequencies, according to the clinical literature
in the field. Fig. 4a shows an image of the experimental set-up
Fig. 4. PD monitoring system and experimental set up to test it, based on [10]. (a) An image of the complete developed set-up; (b) Schematic representation of the
positioning system.
September 2022
IEEE Instrumentation & Measurement Magazine
7

Instrumentation & Measurement Magazine 25-6

Table of Contents for the Digital Edition of Instrumentation & Measurement Magazine 25-6