Brief research report 227

Functional vibratory stimulation on the hand facilitates
voluntary movements of a hemiplegic upper limb in a
patient with stroke
Izumi Shirahashi, Shuji Matsumoto, Megumi Shimodozono, Seiji Etoh and
Kazumi Kawahira
The use of a new device consisting of a small vibrator to
deliver functional vibratory stimulation (FVS) to the arm
resulted in improvements of flexion of the hemiparetic
shoulder in a man with thalamic bleeding. FVS delivered to
the palm enabled the patient to repeat flexing his
hemiparetic shoulder to manipulate objects with his hand.
The functions of the patient’s hemiparetic shoulder and
fingers improved after treatments using FVS for 1 month.
We examined whether FVS of the hemiplegic upper limb
could facilitate voluntary movements of the limb by
increasing the excitability of the motor cortex or the spinal
motor neurons using somatosensory-evoked potentials,
transcranial magnetic stimulation, F-wave, and single
photon emission computed tomography. Our results did
not detect an increase of excitability in the motor cortex or

in spinal motor neurons by FVS. International Journal of
Rehabilitation Research 30:227–230 c 2007 Lippincott
Williams & Wilkins.

Introduction

thalamus and, partially, the internal capsule, was
detected. One month later, he entered our hospital for
rehabilitation treatment for the hemiplegia. The severity
of hemiparesis of the right extremities was Brunnstrom
stage 4 in the upper limb, 6 in the hand, and 5 in lower
limb. As shown in Fig. 2a, 2 weeks later, the patient found
that he could raise his right arm by more than 1351 with
his elbow extended when he held something such as a
soft paper ball or a handkerchief in his right palm;
however, he could raise his arm only by 701 or less when
he held nothing in his right palm. He underwent physical
and occupational therapies, including facilitation exercise, to elicit shoulder flexion in the supine or sitting
positions, or when reaching for a target, or carrying
objects such as pegs, balls, and blocks. Although sensory
stimulation to his hemiplegic hand, induced by gripping
objects, facilitated his shoulder flexion, he was unable to
release these objects during shoulder flexion because his
arm dropped immediately after releasing the objects in
his hand. As shown in Fig. 2, to facilitate his shoulder
flexion without gripping objects, FVS was applied by a
small vibrator fixed to his hemiparetic upper limb. FVS
application to the palm, back of the hand, forearm, and
shoulder facilitated the flexion of the arm, with that on
the palm being most effective. The patient was able to
flex his hemiparetic arm by more than 1351 during FVS,
but the arm dropped when the FVS was stopped during
his shoulder flexion.

Patients with lesions involving the thalamus and internal
capsule might show disturbances in hand function owing
to insufficient shoulder function. In these patients, and
most others with hemiparesis, improving the shoulder
function is necessary to enable them to lift the arms when
they reach for and manipulate objects by hand. Intensive
therapies should include the repetition of facilitation
exercises, which have been shown to improve the
hemiplegic lower limb (Kawahira et al., 2004a). Therapeutic electric stimulation on the shoulder, in addition to
conventional occupational therapy, has been used to
improve function. Here, we report a patient whose
shoulder flexion was facilitated by sensory stimulation
and who showed improvement when reaching out for
objects after treatment using functional vibratory stimulation (FVS) to the palm. FVS has been shown previously
to improve gait speed (Kawahira et al., 2004b). The
mechanisms of action of FVS to the palm, which enabled
the patient to flex his hemiparetic shoulder, were
examined using somatosensory-evoked potentials
(SSEPs), transcranial magnetic stimulation, F-wave, and
single photon emission computed tomography (SPECT).

Case report
A sixty-two-year-old man suffered left thalamic hemorrhage, which resulted in right hemiplegia. As shown in
Fig. 1a, a low-density area on CT, involving the left

International Journal of Rehabilitation Research 2007, 30:227–230
Keywords: stroke, thalamus, upper limb, vibratory stimulation
Department of Rehabilitation and Physical Medicine, Kagoshima University
Graduate School of Medical and Dental Sciences, Kirishima-shi, Kagoshima,
Japan
Correspondence to Megumi Shimodozono, MD, PhD, Department of
Rehabilitation and Physical Medicine, Kagoshima University Graduate School of
Medical and Dental Sciences, 3930-7, Makizono-cho, Kirishima-shi, Kagoshima,
899-6603, Japan
Tel: + 81 995 78 2077; fax: + 81 995 64 4045;
e-mail: izmine@m.kufm.kagoshima-u.ac.jp

0342-5282 c 2007 Lippincott Williams & Wilkins

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228 International Journal of Rehabilitation Research 2007, Vol 30 No 3

Fig. 1

(a) Brain lesion in computed tomography (CT). A low-density area involved in the left thalamus and internal capsule. (b) Functional vibratory
stimulation and the stimulated site of the hemiparetic upper limb. A small vibrator, 18 mm in diameter and 3 mm in height, was stabilized on the
palm by a bandage, to deliver functional vibratory stimulation. The device consisted of one battery, a small vibrator, and a connecting wire.

As part of the treatment using FVS, the patient held a
ball in front of his chest and moved the ball to a high and
far point, which required flexion of the shoulder. After
reaching the target, the patient released the object and
withdrew the arm to the starting point (Fig. 2). FVS to
the palm was switched on, by an occupational therapist,
from the time of holding the ball to that of withdrawing
to the starting point. In addition to conventional
occupational therapy for 40 min, the new FVS treatments
were applied for 20 min a day, 5 days a week. The patient
recovered the flexion of his shoulder by more than 1351
and the manipulation of objects by hand, after 4 weeks of
FVS treatment. The effects of FVS to the palm, which
enabled the patient to flex his hemiparetic shoulder, were
examined using SSEPs, transcranial magnetic stimulation,
F-wave, and SPECT.
Somatosensory-evoked potentials

SSEPs were elicited by electrical stimulation to the
median nerve at the wrist. Recording electrodes were
placed over the scalp, the spine, and peripheral nerves
proximal to the stimulation site. The primary cortical
SSEP component following median-nerve stimulation,
N20, was recorded as a near-field potential over the
parietal areas. The patient’s N20 wave recorded from his
injured side was reduced, compared with that recorded
from his noninjured side (Fig. 3).
Magnetic-evoked potential

Electromyograms were recorded with a gain of 1000 and
5000, using Ag–AgCl surface electrodes over the right

first dorsal interosseous and the right deltoid muscles,
respectively. Magnetic stimulation was given over the
hand and shoulder areas of the motor cortex, using a
hand-held figure-8 coil placed tangential to the scalp,
with the handle pointing posteriorly. A single pulse was
delivered using a Magstim Super Rapid stimulator
(The Magstim Company, Whitland, Carmarthenshire,
Wales, UK). The stimulation intensity to activate the
motor threshold was considered to be the minimum
single-pulse intensity required to produce a magneticevoked potential in more than five out of ten trials from
the contralateral first dorsal interosseous muscle; during
these trials, the patient would maintain a voluntary
contraction of about 20% of maximum, using visual
feedback. The patient’s hand did not react to either the
application or nonapplication of an FVS to his palm. The
magnetic-evoked potential from the right deltoid muscle
was not recorded when the maximum stimulation
intensity was given.
The F-waves

The F-waves and M-responses were recorded from the
short abductor muscles of the thumb, after supramaximal
percutaneous electrostimulation of the median nerve at
the wrist, using bipolar surface electrodes (Eisen et al.,
1977). The stimuli were adjusted to be 20% above the
threshold of the maximum M-response. Twenty F-waves
were recorded after the supramaximal current pulses at a
rate of 0.5/s (0.5 ms duration). A stimulus rate of 0.5 Hz
was used to elicit the F-responses, with a total analysis
time of 100 ms. The cathode was placed proximally. The

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Vibratory stimulation on hemiparetic upper limb Shirahashi et al. 229

Fig. 2

Improvements of the patient’s shoulder flexion by vibratory stimulation to the palm. (a) He could not raise his right arm more than 701 when he held
nothing in his right palm. (b) and (c) He could raise his right arm by more than 1351, but only when he had a block and a soft paper ball in his right
palm. (d) He could raise his hand with a vibratory stimulation to his palm. (e) He held a ball before his chest and carried it to a high and distant point;
this action necessitated flexion of the shoulder, reaching, releasing objects and withdrawing to the starting point when functional vibratory stimulation
was delivered to his right palm.

measurement of F-waves in the patient was carried out
with the patient at rest, when being stimulated by FVS,
and after stimulation. No changes in F-waves resulting in
an improvement of shoulder flexion were found.
Single photon emission computed tomography

SPECT was performed before and after FVS. The initial
SPECT began by injecting 99 mTc-ECD into the patient
in 9 minutes. FVS for 30 s began when the initial SPECT
ended and was maintained for 3 minutes during a second
injection of 99 mTc-ECD. After 6 min, the second
SPECT began. The increase in rate from the initial
SPECT to the second SPECT was calculated. An increase
was not observed in the motor area, but was observed in
the sensory area.

Discussion
Previously, we described the utility of an FVS device that
delivers vibratory stimulation whenever necessary, regardless of the posture or motion of the patient (Kawahira
et al., 2004b). In this case report, we demonstrated that
targeted FVS to the palm of the hemiplegic upper limb
significantly improved the flexion of the shoulder in a
patient with a thalamic lesion whose shoulder flexion was
facilitated by holding something in the hand.
The physiological effects of vibratory stimulation have
been studied previously on muscle strength, standing
balance, and sensory-motor systems. Few reports, however, consider the effects of vibratory stimulation during
walking in healthy patients (Ivanenko et al., 2000).

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230

International Journal of Rehabilitation Research 2007, Vol 30 No 3

Fig. 3

Somatosensory-evoked potential: SSEP
C3′-Fz
N20
C4′-Fz

N20

Right median nerve
Left median nerve
Gain/analysis: 1 µV/5 ms
The primary cortical somatosensory-evoked potentials (SSEP)
component following median-nerve stimulation. N20 is recorded as a
near-field potential over the parietal areas. A picture of electric
stimulation to the patient’s hemiplegic median nerve is on the left, and
to his nonhemiplegic one on the right. The N20 wave in the injured side
of his brain was smaller than that in the noninjured side.

Conventional vibrators have been used as therapeutic
tools, but their size has made it difficult to deliver
vibratory stimulation in active patients. In this study, FVS
delivered to the palm enabled the patient to flex his
hemiparetic shoulder and to manipulate objects with his
hand. This improvement might be due to the increase in
sensory input to the thalamus and sensory cortex. Training
of the upper limb, including fingers, to recover voluntary
movements, in patients with motor dysfunction due to
decrease of sensory input, might be reduced by FVS.
Little physiological evidence exists, however, that vibratory stimulation to different body regions facilitates
muscle contraction far from the stimulated body parts.
The mechanisms of FVS to the palm, which enabled our

patient to flex his hemiparetic shoulder, were examined
using SSEP, transcranial magnetic stimulation, F-wave,
and SPECT. Changes in the excitability of the cerebral
motor cortex and spinal motor neurons, or an increase in
the blood flow in the cerebral motor cortex during FVS to
the palm, were not detected. An increase in blood flow to
the sensory cortex was, however, detected, which might
stimulate the functions of the motor cortex. Of course,
FVS to the palm can directly stimulate motor neurons in
the spinal cord and the cerebral motor cortex through the
activation of the thalamus.
Further research is needed to better define the mechanisms of functional motor recovery in hemiplegic patients
using FVS during voluntary movements.
Conclusion

Targeted FVS to the palm of the hemiplegic upper limb
significantly improved the flexion of the hemiparetic
shoulder in a patient with a thalamic lesion, whose
shoulder flexion was facilitated by holding something in
the hand. FVS can be a useful treatment modality during
therapeutic exercise for hemiparetic extremities.

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Ivanenko YP, Grasso R, Lacquaniti F (2000). Influence of leg muscle vibration on
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Kawahira K, Shimodozono M, Ogata A, Tanaka N (2004). Addition of intensive
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