IEEE Robotics & Automation Magazine - September 2022 - 43

between 150 cm (short) and 176 cm (tall), and the weight
is between 45 kg (thin) and 80 kg (fat). Hence, the selected
patients are representative, in the sense that patients with
different body parameters have been considered. The
selection also covers different medical conditions, ranging
from new cases (e.g., 15 days ago) to long-standing ones
(e.g., 162 days ago). In addition, the number of CIs is double
that of CH, which is reasonable and matches the occurrence
probability in clinical trials.
The formal trial is carried out as follows: 1) BEAR-H is
tested to ensure that the system functions properly; 2) the
conditions of the subject are evaluated by measuring blood
pressure and heart rate, and the trial proceeds if all readings
are normal; 3) the clinical staff help the patient to wear the
robot, fasten the safety belt of the stand, and then input the
body parameters of the patient; 4) the patient starts to walk
once the robot is activated; 5) during the walking phase, the
doctor and clinical staff continue to monitor the procedure
and take action to stop the trial if any safety issues arise; and
6) after the walking phase is complete, the patient takes off the
robot, and the staff measures the blood pressure and heart
rate of the patient again.
Comparative studies were performed in the clinical trials,
where all 30 patients are equally divided in two groups:
Group 1 includes patients from number 1 to 15 who were
subject to the traditional manual rehabilitation, that is, an
experienced therapist holds and assists the patient during the
walking test. Group 2 includes patients from number 16 to
30 who were subjected to robotic rehabilitation by wearing
BEAR-H with minimal manual assistance (the doctor intervenes
only when there might be a safety issue). Both groups
have the similar distribution of body parameters and medical
conditions given in Table 5.
Experimental Results
The performance of BEAR-H was studied in the six-minute
walk test (6MWT) [17], where the patient wears the robot and
then walks continuously for six minutes. During the walking
phase, the doctor accompanies the patient with minimal communication
(i.e., the doctor talks to the patient to encourage
him/her), and the patient can rest between the two tests.
The trials were performed in a closed corridor such that other
pedestrians could not interrupt. The walking path is straight
and solid, and the total length is more than 30 m. There is a
returning sign at the end of the path, and there are also a series
of reminders every 5 m.
In the first experiment, the heart rate of the patient
before and after 6MWT are recorded and compared. For
example, a variation of 10% of heart rate implies that the
patient's heart rate after walking increases for 10% with
respect to that before walking. Note that smaller increases in
heart rate implies better effect, where the assistance from
doctor/robot benefits the patient's motion such that the
patient is relaxed while walking. Significant increases in
heart rate is a sign of ineffective training, indicating that the
patient is not comfortable with the assistance from the
(b)
Figure 7. Clinical trials were performed to validate the performance
of the robot. (a) Hemiplegia patients were involved in clinical trials.
(b) The patient wears the robot and walks on the ground, where
the metabolic data before and after walking are compared to
study the performance of BEAR-H.
Table 5. A statistical summary of the patients.
Parameter
Count Mean
Age
(years)
Height
(cm)
Weight
(kg)
Duration
(days)
-
- 30
- 30
- 30
167.27 6.87
64.87 8.8
89.4 46.23
Causes CH 10 -
CI 20 -
-
-
150
45
16
-
-
176
80
162
-
-
- 30
50.67 12.81
22
72
doctor/robot and needs to exert additional effort while
walking. The experimental results are presented in Figure 8,
where the blue bar denotes the heart rate before walking,
and the red bar denotes the heart rate after walking. The
(a)
Standard
Deviation Minimum Maximum
SEPTEMBER 2022 * IEEE ROBOTICS & AUTOMATION MAGAZINE *
43
IEEE Robotics & Automation Magazine - September 2022

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