Hindawi Publishing CorporationParkinson's DiseaseArticle ID 390512
The Parkinsonian Gait Spatiotemporal Parameters Quantified
by a Single Inertial Sensor before and after
Automated Mechanical Peripheral Stimulation Treatment
Ana Kleiner,1,2 Manuela Galli,1,3 Maria Gaglione,4 Daniela Hildebrand,5 Patrizio Sale,3
Giorgio Albertini,3 Fabrizio Stocchi,3 and Maria Francesca De Pandis4
1Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20133 Milano, Lombardia, Italy
2Movement Analysis and Neuroscience-Neurological Rehabilitation Laboratories, University of Health Sciences of Porto Alegre,
90050-170 Porto Alegre, RS, Brazil
3IRCCS San Raffaele Pisana Tosinvest Sanit´a, 00163 Roma, Lazio, Italy
4San Raffaele Cassino Hospital Tosinvest Sanit´a, 03043 Roma, Lazio, Italy
5UNIMED Hospital, 13500-391Rio Claro, SP, Brazil
Correspondence should be addressed to Ana Kleiner; [email protected]
Received 29 May 2015; Revised 5 August 2015; Accepted 2 September 2015
Academic Editor: Talia Herman
Copyright 2015 Ana Kleiner et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This study aims to evaluate the change in gait spatiotemporal parameters in subjects with Parkinson's disease (PD) before andafter Automated Mechanical Peripheral Stimulation (AMPS) treatment. Thirty-five subjects with PD and 35 healthy age-matchedsubjects took part in this study. A dedicated medical device (Gondola) was used to administer the AMPS. All patients with PD weretreated in off levodopa phase and their gait performances were evaluated by an inertial measurement system before and after theintervention. The one-way ANOVA for repeated measures was performed to assess the differences between pre- and post-AMPSand the one-way ANOVA to assess the differences between PD patients and the control group. Spearman's correlations assessed theassociations between patients with PD clinical status (H&Y) and the percentage of improvement of the gait variables after AMPS(𝛼 < 0.05 for all tests). The PD group had an improvement of 14.85% in the stride length; 14.77% in the gait velocity; and 29.91% inthe gait propulsion. The correlation results showed that the higher the H&Y classification, the higher the stride length percentage ofimprovement. The treatment based on AMPS intervention seems to induce a better performance in the gait pattern of PD patients,mainly in intermediate and advanced stages of the condition.
. However, as the disease progresses, chronic levodopatreatment can be associated with response decrease and with
The most typical gait pattern of Parkinson's disease (PD) is
development of motor complications, including wearing-off
a short-stepped shuffling gait. It is characterized by reduced
episodes and dyskinesia .
stride length and walking speed [1, 2]. These gait disorders
To reduce these motor fluctuations, new treatments based
worsen progressively, as the disease advances, and are related
on peripheral stimulation of the sensory-motor system, called
to the risk of falling among the Parkinsonians . Therefore,
bottom-up stimulation, have been inspiring new rehabili-
it is not surprising that gait impairment in PD is the major
tation approaches in PD [7, 8]. Recently, new approaches
contributor to decreased patients' quality of life .
have been developed to recover the gait impairment such as
The management of PD was traditionally centered on
the Automated Mechanical Peripheral Stimulation (AMPS)
drug therapy, with levodopa being its "gold standard" treat-
treatment [9, 10]. The AMPS is delivered by a dedicated
ment . Several studies have demonstrated the ability of
device, known as Gondola (Gondola Medical Technologies
levodopa to decrease stride length and improve walk speed
SA, Switzerland), and consists in the application of a pressure
via rounded stimulation tips in the four areas to be stimulated
Table 1: Anthropometric characteristics.
(two in each foot, which are the head of the big toe and thefirst metatarsal joint).
Stocchi et al.  evaluated the change in gait and the
clinical status of 18 patients with PD after 6 sessions of a
treatment based on AMPS. The study results indicate that
the AMPS treatment has positive effect on bradykinesia and
allows the improvement of walking velocity. Furthermore,
AMPS has a positive effect on the step and stride length andon walking stability, measured as the increase in stride length
and the reduction of double support time during walk. These
results are consistent, and the results of improvement weremeasured via clinical scales.
Also recently, Galli et al.  evaluated a group of PD
patients before and after AMPS evaluated with the Timed
The study has been approved by the Ethics Research
Up and Go (TUG) test, a widely used clinical performance-
Committee of the IRCCS San Raffaele Institute. The trial
based measure of fall risk, measured with inertial sensors. The
was registered online at ClinicalTrials.gov (identifier number
AMPS treatment improves the walking stability and seems to
NCT01815281). All procedures were explained to the partici-
reduce the risk of falls in patients with PD. After the AMPS
pants and were carried out with their adequate understand-
patients performed the TUG test faster and improved some
ing, after receiving their written informed consent.
kinematic parameters as the velocity to stand up from a chairand to sit down.
2.2. Experimental Procedures.
During all intervention PD
Based on these findings, the current study aims to evalu-
patients were in off phase, after an overnight withdrawal of
ate the impact of the AMPS in functional abilities, measured
all anti-Parkinsonian treatments.
with gait spatiotemporal parameters based on a single inertialwearable sensor. Recently, wireless inertial sensing devicesare being developed also for the assessment of spatial-
2.2.1. The Automated Mechanical Peripheral Stimulation
temporal parameters in unobstructed environment outdoors,
The treatment consists in the application of a pres-
thus overcoming the typical limitations of measurements
sure via rounded stimulation tips in four specific target areas
in indoor laboratory settings. Several applications in the
in patient's feet (Figure 1(a)). To perform this mechanical
rehabilitation and recovery of patient mobility have been
stimulation, a dedicated medical device (Gondola, Gondola
already reported by using these devices [11–14], more specific
Medical Technologies, Lugano, Switzerland) was used to
in patients with PD [5, 15–17].
deliver the AMPS (Figure 1(b)). The system consists of feet
The aim of this study was to assess and to quantify if the
supports (left and right) with electrical motors which activate
AMPS is capable of promoting changes on spatiotemporal
two actuated steel bars with a 2 mm diameter; the motor-
parameters of PD gait. More specifically, this paper aims
activated stimulators apply a mechanical pressure in two
to assess the associations of the patients' clinical status
specific areas of each foot: on the head of the hallux, left and
with the percentage of improvement of the gait variables
right, and on the 1st metatarsal joint, left and right.
(stride length, velocity, cadence, and propulsion) after AMPS.
Before treatment, the device needs to be adjusted to the
The hypothesis of this study is that the AMPS stimulation
patient's feet (Figure 1(c)): an inner sole of the correct size
improves the spatiotemporal gait of patients with PD, and the
is inserted in each unit (left and right) to accommodate the
more compromised the patient is, the more benefits he/she
feet; then the feet are inserted in the two units and tied up,
will have after the bottom-up rehabilitation.
using three straps per foot; after that, correct length steel barsare mounted on the axis of the electrical motors. The next
step consists in positioning the motors that are mounted onadjustable platforms in order to make the steel bars interact
The Parkinson group (PD) consisted in 35
with the areas to be stimulated (head of the hallux and first
patients affected by Parkinson's disease. PD was diagnosed
metatarsal joint of both feet). Once the device is adjusted,
based on clinical criteria [18, 19], dopamine transporter (DaT)
the excursion of the four motors (which work independently
scans, and/or magnetic resonance imaging. All these patients
from each other) is programmed (using a remote control),
are similar in terms of disease duration and are free of
aiming to apply the correct pressure stimulation on each area.
peripheral sensory neuropathy and other disorders based on
The pressure of stimulation, always applied in a range of 0.3–
their reported histories, symptoms, physical examinations,
0.9 N/mm2, is set for each subject upon appearance of the
and clinical tests. Patients with liver, kidney, lung, or heart
monosynaptic reflex in the Tibialis Anterior muscle by the
diseases, diabetes, or other causes of autonomic dysfunction
detection of a liminaris contraction while applying pressure
were not included in the study.
in the contact areas.
The characteristics of the considered subjects are sum-
Once the pressure value has been set using this procedure,
marized in Table 1. The control group (CG) consisted in 35
the value is recorded to administer the AMPS. This prepara-
healthy adults with the average characteristics in Table 1.
tory procedure requires approximately 10 minutes.
Figure 1: The device used for the AMPS treatment: (a) the specific points of feet stimulation; (b) the two moving steel bars; (c) patientpositioning.
The treatment consists in 4 cycles; one cycle includes
signals, the following typical spatial-temporal gait parameters
a stimulation of the 4 target areas requiring 24 seconds,
whereas the overall 4-cycle treatment lasts for a total of 96seconds. During the AMPS treatment, patients lay down
(i) Stride length [m], the distance between two consecu-
(Figure 1(c)). At the end of the AMPS stimulation, both units
tive heel strikes of the same foot.
of the device are removed from the feet of the patient; this
(ii) Stride length/height [%], the stride length normalized
final action is very easy and fast (less than 1 minute). This
by subject height.
link shows images of a pre- and post-AMPS patient's gait(https://www.youtube.com/watch?v=deHFpt5gk3A&feature=
(iii) Speed [cm/s], the average instantaneous speed within
the gait cycle as integration of acceleration.
(iv) Cadence [strides/min], the number of strides in a
2.2.2. The Inertial Sensor.
The single inertial sensor is a wire-
less inertial sensing device (GSensor, BTS BioengineeringS.p.A., Italy) which provides acceleration along three orthog-
(v) Propulsion [m/s2], the anterior-posterior acceleration
onal axes: anteroposterior, mediolateral, and superoinferior.
peak during the lower limb swing phase.
Acceleration data were transmitted via Bluetooth to a PCand processed using dedicated software (BTS G-STUDIO,
2.3. Statistical Analysis.
For statistical analysis, the data were
first tested for normality with the Kolmogorov-Smirnov
The portable GSensor consists in a wireless network of
test. Because all the behavioral data exhibited normal dis-
inertial sensors for human movement analysis. The sensors
tributions, parametric statistics were applied. The one-way
are controlled by a data logger unit (up to 16 elements),
ANOVAs (𝛼 < 0.05) were applied to compare the anthro-
a ZigBee radio type communication. Each sensor is sized
pometric data (i.e., age, body mass, and height) between the
62 mm × 36 mm × 16 mm, weighs 60 g, and is composed of
PD group and the CG. Furthermore, this test was applied
a 3-axis accelerometer (max range ± 6 g), a 3-axis gyroscope
to compare the differences between the right and the left
(full scale ± 300∘/s), and a 3-axis magnetometer (full scale ± 6
lower limbs of the PD group and the CG. Once no significant
gauss). This sensing device is calibrated with the gravitational
differences were found between the right and left limbs, the
acceleration immediately after its manufacturing process.
left limb was selected to represent the CG and PD bodies for
Only one sensor was used during this work. It was attached
all gait variables comparisons.
to the subjects' waists with a semielastic belt, covering the L4-
Then, the described parameters were computed for each
L5 intervertebral space. The acceleration was analyzed about
participant and for each trial, and significant values and stan-
the three orthogonal anatomical axes: the anterior-posterior,
dard deviations of all indexes were calculated for each group.
mediolateral, and vertical axes.
After verifying that the parameters were normally distributed
The reference coordinate frame had the 𝑧-axis oriented
by means of Kolmogorov-Smirnov test, the one-way ANOVA
to the front, 𝑥-axis oriented vertically upward, and 𝑦-
for repeated measures (𝛼 < 0.05) was performed to assess the
axis orthogonal to the other two, towards the right. This
differences between pre- and post-AMPS; also, the one-way
motion analysis was performed with a sensitivity for the
ANOVA for independent measures (𝛼 < 0.05) was performed
F4A accelerometer of 3G and a sampling frequency of 50 Hz.
to assess the differences between PD before and after AMPS
Acceleration data were transmitted via Bluetooth to a PC
and control group.
and processed with the use of dedicated software (BTS G-
Next, Spearman's correlations (𝛼 < 0.05) were used to
STUDIO, version: 188.8.131.52), which automatically provides the
assess the associations between the Hoehn & Yahr (H&Y)
parameters described next.
 patient with PD clinical status and the percentage of
All study participants were asked to walk at a self-selected
improvement of the gait variables (stride length, velocity,
speed along a pathway. Then, from the collected acceleration
cadence, and propulsion) after AMPS. The interpretation of
Figure 2: Significance and standard deviation of gait spatiotemporal parameters before and after AMPS: (a) stride length; (b) velocity; and(c) propulsion. ∙ = 𝑃 < 0.05 between pre- and post-AMPS; + = 𝑃 < 0.05 between PD and control group.
the correlation degree is as follows: 0.9 to 1 indicated a very
high correlation; 0.7 to 0.9 indicated a high correlation; 0.5
to 0.7 indicated a moderate correlation; 0.3 to 0.5 indicated a
low correlation; and 0 to 0.3 indicated little to no correlation.
All tests were two tailed. SPSS (version 19, IBM, Armonk,
New York, United States) was used to perform all statistical
Figure 2 illustrates the spatiotemporal gait parameters results
before and after AMPS. The patients with PD post-
AMPS treatment presented longer stride length (Figure 2(a));
higher gait velocity (Figure 2(b)); and higher propulsion
Figure 3: Correlation observed between the PD clinical status
(H&Y) and the stride length percentage of improvement (stride
For the 35 PD patients evaluated; 57.14% had H&Y stage 4;
length %) after AMPS.
20% had H&Y stage 3; 5.71% had H&Y Stages 2 and 5; 8.57%had H&Y Stages 1 and 5; and 8.57% had H&Y stage 1. Figure 3illustrates a significant and high positive correlation observedbetween the clinical status of the PD patients (H&Y) and the
stride length percentage of improvement after AMPS (𝜌 =0.733; 𝑃 = 0.013). The more compromised the PD patient,
The aim of this study was to evaluate the effect of AMPS
the higher the percentage of the stride length improvement
treatment in PD subjects using a single inertial sensor to
after AMPS intervention.
quantify the gait spatiotemporal parameters. Supporting our
hypothesis, this study's results indicated that the AMPS
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GUÍA DE PROCEDIMIENTOS LABORALES: PROCEDIMIENTOS ADMINISTRATIVOS, JUDICIALES E INTERNACIONALES DE PROTECCIÓN DE LOS DERECHOS LABORALES Dr. Max PuigMinistro de Trabajo Equipo de coordinación Sandra Dueñas-PaschalGerente RegionalPact Andrés Valentín Herrera GonzálezDirector general de TrabajoMinisterio de Trabajo Rafael Arturo Mariano OviedoDirector de Asistencia JudicialMinisterio de Trabajo
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