Journal of Robotics, Networking and Artificial Life, Vol. 3, No. 1 (June 2016), 33-36

Clinical Evaluation of UR-System 2 for Recovery of Motor Function ofPlegic Upper Limb after Stroke
Hirofumi Tanabe, Masahiro Mitsukane

Department of Health Sciences, Shonan University of Medical Sciences
16-48 Kamishinano, Totsuka-ku, Yokohama, Kanagawa 244-0806, Japan
E-mail: hirofumi.tanabe@sums.ac.jp
Norihiro Toya, Ryosuke Takeichi, Hitomi Hattori, Yoshifumi Morita

Nagoya Institute of Technology
Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
Yoshiaki Takagi, Norio Hasegawa

Sanyo Machine Works, Ltd.
1 Oka, Okimura, Kitanagoya-shi, Aichi 481-8540, JapanAbstract
We developed a new training system UR-System 2 for restoring motor function of the upper limb after stroke inpatients with hemiplegia. And then, we conducted clinical evaluation of the therapeutic effect of training with theUR-System 2 in six patients. The UR-System uses Proprioceptive Neuromuscular Facilitation (PNF) to promotemuscle strength. The results show the immediate therapeutic effect of training with the UR-System 2 for restoring
the motor function of the upper limb.
Keywords: Rehabilitation, Training system, Hemiplegic stroke patient, Clinical evaluation, PNF

1. Introduction
The synergy movement pattern often seen in hemiplegicpatients after stroke is one of the factors inhibiting
improvement of motor function. According to theBrunnstrom recovery stages of hemiplegia, elbow
flexion, pronation/supination of the forearm, wrist
flexion, and finger flexion occur abnormally andsimultaneously in hemiplegic patients during the earlystage of recovery; this is called the synergy movement
pattern. In the recovery stage, a patient gradually
evolves from a synergy movement pattern, and will beable to extend the elbow, supinate the forearm, andextend the wrist and fingers1. Proprioceptive
Neuromuscular Facilitation (PNF) is an effective
therapy facilitating recovery from spastic paralysis2, 3.
Since this repetitive technique is performed manually,

the therapist’s physical workload is considerable.
Therefore, we are developing a training system forrecovery of normal movement isolated from synergy
movement patterns by facilitating contraction of elbow
extension and forearm supination muscles.
In our previous work4, we developed a training
system (UR-System: Useful and Ultimate Rehabilitation
System) for recovery of motor function of the upper
limb after stroke in patients with hemiplegia. Thissystem uses PNF to promote muscle strength. Clinicalevaluation of the therapeutic effect of training with theUR-System was performed in eight patients for twoweeks. Active ranges of motion (A-ROMs) of elbow
extension and forearm supination improved after
training with the UR-System. Moreover, the modified
Ashworth scale (MAS) scores5 for elbow extension andforearm supination increased. This means that spastic

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H. Tanabe, M. Mitsukane, N. Toya, R. Takeichi, H. Hattori, Y. Morita, Y. Takagi, N. Hasegawa

paralysis was reduced. This shows the effectiveness oftraining with the UR-System for recovery of motor
function of the upper limb.
However, the following problems persist. Since theUR-System was not equipped with sensors that canmeasure the movement of the paralyzed forearm and theforce/torque exerted by the forearm, the therapeutic
effect was not evaluated in detail (Problem I). It wasdifficult for therapists to adjust the parameters of therubber belt to facilitate elbow extension suitable for thepatient’s condition (Problem II).
In order to solve these problems this study
developed a new training system, the UR-System 2. We
evaluated the immediate therapeutic effect of recoveryof motor function by training with the UR-System 2.
2. UR-System 2
To solve Problem I, we introduced sensors on the brace.
To solve Problem II, we developed an elbow-pushingarm on the brace in place of the rubber belt to facilitate
elbow extension. Moreover, since the previous URSystem was over-engineered, we reconsidered thespecifications, and developed the UR-System 2. As aresult, the number of parts, weight of the mechanicalsystem, and total cost decreased.
The UR-System 2 is a force display system with one
degree of freedom. The system consists of a mechanicalsystem and a controller. The mechanical system consistsof a training arm, a powder brake (SINFONIATECHNOLOGY CO., LTD., PRB-2.5H), and a brace.
The brace was used to secure the patient's forearm to thetraining system. The patient moves the training arm
independently. The powder brake generates a resistanceforce during training. Four different resistance patterns,i.e., step, slope, wall, and constant modes, were installedin the controller. The length of the training arm can bealtered within the range of 0.60-0.89 m. The maximum
resistance is 49 N when the length of the training arm is0.75 m.
The brace has three degrees of freedom, allowing
rolling, yawing, and pitching motions of the fixing
plate. The rolling motion can be switched between freemotion and fixed motion with a double nut. When theUR-System 2 is used in training, the rolling motion isfixed, but is allowed when evaluating the therapeuticeffect. The brace is equipped with three potentiometers(ALPS ELECTRIC CO. LTD., RDC803001A) and a 6axis
forcesensor(LeptrinoCo.
Ltd.,
PFS055YA251A6). The potentiometers measure roll,yaw, and pitch angles of the fixing plate of the brace.
The 6-axis force sensor measures the force and torquebetween the forearm and the fixing plate. An elbowpushing arm is installed on the fixing plate to facilitate
elbow extension. As the patient moves the forearm
forward, the elbow-pushing arm pushes the elbow tofacilitate contraction of a deltoid muscle. The elbowpushing arm is rigid and does not bend to the externalforce. The contact portion of the elbow-passing arm to
the deltoid muscle is made by harder cushion. When theforearm is fixed to the brace, the portions of the forearm
near the wrist and the elbow are fixed with a nonexpandable bandage and an expandable bandage,respectively. Therefore, the portion of the forearm near
the elbow can leave the brace due to the extensibility ofthe expandable bandage. Moreover, the patient canextend his/her elbow fully in spite of the existence ofthe elbow pushing arm. If a non-expandable bandage is
not used, the patient cannot extend his/her elbow fully.
Because this system is not equipped with motors, it
is extremely safe and economical. It should be notedthat the system is used only for active exercise training.
The UR-System 2 was equipped with variousfunctions. The resistance display function allows
therapists to perform various types of resistance training
by changing the arm length and the resistance level. The
touch panel parameter setting function allows theparameters of the resistance patterns to be easily set bypushing buttons on the touch panel display. The
parameters consist of the magnitudes and positions of
the resistance patterns. The magnitudes are selectedfrom among twenty-five levels. The positions aredetermined by moving the training arm to the desiredposition. This function provides good visibility and easy
operability for the therapist.
The resistance to the movement of the forearm andcompression of the elbow are expected to facilitate
elbow extension. These concepts are based on
facilitation elements, namely resistance to movement,compression arthrodesis, passive movement, andmanual contact in PNF techniques. Therefore, thepatient is expected to extend the elbow joint fully.
Moreover, pronation and supination of the forearm,

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Clinical Evaluation of UR-System 2

wrist flexion, and finger flexion are not permitted
during elbow extension and flexion, because theforearm is fixed on the fixing plate of the brace,
preventing a synergy movement pattern from occurring.
Therefore, isolated movement should be facilitated byusing the UR-System 2.
3. Clinical Evaluation of Therapeutic Effect3.1. Method
We evaluated six patients who satisfied the following
conditions:1) The subject had a hemiplegic upper limb after astroke.
2) More than one year had passed since stroke onset.
3) The subject did not have pain in training with theUR-System 2.
4) The Brunnstrom Stage was IV or V.
The post-stroke durations were 10 years in Subject A,
12 in Subject B, two in Subject C, four in Subject D,
one and one-half in Subject E, and five in Subject F. Weobtained written consent from all patients.
We used two training protocols for a comparative
study. One employed training without PNF-facilitating
elements, namely resistance and compression
arthrodesis, and was referred to as Control-training. The
other employed training with PNF-facilitating elements,
and was referred to as PNF-training. PNF-training wasperformed at least three days after Control-training.
The patient performed repeated training for elbow
flexion and extension with the paralyzed forearm in thesupinated position. Repeated training was performed 50
times per set for five sets. The rest time between setswas 5 minutes.
The therapeutic effects of training with the URSystem 2 were assessed using the MAS and the A-ROM
test before and after training, and were compared withthose of Control-training and PNF-training.
3.2. Results and discussion
All subjects completed two types of training with theUR-System 2. Table 1 presents the summary of scoresfor outcome measures. Table 1 shows that the A-ROMs
and MAS score in PNF-Training increased significantly
after training. Figures 2-4 show the A-ROMs and MAS
score were improved greatly in PNF-Training ascompared with Control-training. Thus, isolated

movement was facilitated by PNF-training with the URSystem 2. The immediate effect of restoring motor
function in PNF-training was excellent as comparedwith Control-training. Moreover, it is noteworthy thatmotor function was restored even in Patients A and B,
who had stroke episodes more than ten years prior totraining. Consequently, training with the UR-System 2
can immediately improve motor function of the upper
limb after stroke in patients with hemiplegia.
Since the therapeutic effect shown in this study isimmediate, we will investigate this effect after daily
continuous PNF-training. Moreover, the workload oftherapists will decrease because the system can be used
for independent training for recovery of motor function.
4. Conclusion
The immediate therapeutic effect of PNF-training with
the UR-System 2 was shown from the results of theclinical evaluation. PNF-training with the system canimmediately improve motor function of the hemiplegic
upper limb.
In a future study, we will confirm the therapeuticeffect after daily continuous PNF-training with thesystem 2 for a larger number of subjects, and develop a
training method for recovery of motor function of theshoulder and lower extremities of hemiplegic patientsby modifying the UR-System 2.
References
1. I. Safaz, B. Ylmaz, E. Yaşar, R. Alaca, Brunnstrom
recovery stage and motricity index for the evaluation ofupper extremity in stroke: Analysis for correlation andresponsiveness, Int. J. Rehabilitation Res., 32(3) (2009),
pp. 228-231.
2. J. Stein, R. Harvey, C. Winstein, G. Wittenberg, R.
Zorowitz, Stroke recovery and rehabilitation, Demos
Medical Publishing, (NY,2008).
3. K. B. Hindle, T. J. Whitcomb, W. O. Briggs, J. Hong,
Proprioceptive neuromuscular facilitation (PNF): Itsmechanisms and effects on range of motion and muscularfunction, J. Hum. Kinet., 31 (2012), pp. 105–113.
4. Y. Morita, N. Sato, H. Ukai, H. Tanabe, T. Nagao, R.
Tanemura, Y. Takagi, Y. Aoki, Clinical evaluation oftraining system for recovery of motor function afterstroke in patients with hemiplegia, Proc. of the 2nd Int.
Conf. on NeuroRehabilitation (ICNR2014) (2014), pp.
83-92.
5. Ashworth B, Preliminary trial of carisoprodal in multiple
sclerosis, Practitioner, 192 (1964), pp.540-542.

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H. Tanabe, M. Mitsukane, N. Toya, R. Takeichi, H. Hattori, Y. Morita, Y. Takagi, N. Hasegawa

25,020,0Controller box

15,8Brace

A-ROM

15,0Elbow pushing arm

10,05,00,0-5,0Training arm

1,7Control

PNF-10,0Powder BrakeFig. 2. Improvement of A-ROM of elbow extension.

(a) A-ROM of elbow extension.
ControlPNF
Subject
Pre Post Diff. Pre Post Diff
A-20 -15+5-20-5+15B-15 -25-10 -15-5+10C-25 -25+0-25 -10 +15D-20 -15+5-200+20E-20 -15+5-20 -10 +10F-30 -15+5-30-5+25(b) A-ROM of supination of forearm.
Control
PNF
Subject
Pre Post Diff. Pre Post Diff.
A6575+106590+25B
4055+154070+30C55
60+55565+10D3545+103555+20E
4065+254070+30F
6575+1065
90+25(c) MAS Score of elbow flexor group.
ControlPNF
Subject
Pre Post Diff. Pre Post Diff.
A44045+1B
44045+1C
34+134+1D
33034+1E
34+134+1F
33034+135,030,023,325,0A-ROM

Table 1. Summary of scores for outcome measures(Control: Control-training, PNF: PNF-training,
Pre: Before training, Post: After training,
Diff: Difference between the results before and after training,
Positive difference values mean improvement.)

20,015,012,510,05,00,0ControlPNF

Fig. 3. Improvement of A-ROM of supination of forearm.
1,4
1,2

1,01,0MAS score

Fig. 1. UR-System 2.

0,80,60,40,30,20,0-0,2Control

PNF

Fig. 4. Improvement of MAS Score of elbow flexor group.

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