Effect of thermal stimulation on upper extremity motor recovery 3 months after stroke.
ABSTRACT To examine the effect of thermal stimulation (TS) on upper extremity (UE) motor recovery in patients at least 3 months after stroke.
Participants were randomly assigned to either the experimental group or the control group. In addition to regular rehabilitation programs, the experimental group received an UE-TS protocol for 30 minutes per day (3 days/week for 8 weeks); the control group received the same TS protocol on lower extremity. The UE subscale of the Stroke Rehabilitation Assessment of Movement and the Action Research Arm Test were primary outcome measures. The Modified Ashworth Scale and the Barthel Index were secondary outcome measures. All measures were administered at baseline, after TS, and at 1-month follow-up.
Twenty-three participants (12 in the experimental group) completed the study. After treatment, the experimental group showed significant improvement compared to the control group in the scores of the UE subscale of the Stroke Rehabilitation Assessment of Movement and Action Research Arm Test. At follow-up examination, a significant improvement in the experimental group was observed on the UE subscale of the Stroke Rehabilitation Assessment of Movement.
The 8-week additional UE-TS protocol improved UE motor recovery for stroke patients 3 months after onset.
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Hung-Chia Wu, Yu-Ching Lin, Miao-Ju Hsu, Shin-Mei Liu, Ching-Lin Hsieh and
Effect of Thermal Stimulation on Upper Extremity Motor Recovery 3 Months
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Effect of Thermal Stimulation on Upper Extremity Motor
Recovery 3 Months After Stroke
Hung-Chia Wu, MSc; Yu-Ching Lin, MD, MSc; Miao-Ju Hsu, PhD; Shin-Mei Liu, MSc;
Ching-Lin Hsieh, PhD; Jau-Hong Lin, PhD
Background and Purpose—To examine the effect of thermal stimulation (TS) on upper extremity (UE) motor recovery
in patients at least 3 months after stroke.
Methods—Participants were randomly assigned to either the experimental group or the control group. In addition to regular
rehabilitation programs, the experimental group received an UE-TS protocol for 30 minutes per day (3 days/week for
8 weeks); the control group received the same TS protocol on lower extremity. The UE subscale of the Stroke
Rehabilitation Assessment of Movement and the Action Research Arm Test were primary outcome measures. The
Modified Ashworth Scale and the Barthel Index were secondary outcome measures. All measures were administered at
baseline, after TS, and at 1-month follow-up.
Results—Twenty-three participants (12 in the experimental group) completed the study. After treatment, the experimental
group showed significant improvement compared to the control group in the scores of the UE subscale of the Stroke
Rehabilitation Assessment of Movement and Action Research Arm Test. At follow-up examination, a significant
improvement in the experimental group was observed on the UE subscale of the Stroke Rehabilitation Assessment of
Conclusions—The 8-week additional UE-TS protocol improved UE motor recovery for stroke patients 3 months after
onset. (Stroke. 2010;41:00-00.)
Key Words: motor recovery ? stroke ? thermal stimulation
tients because TS may induce cortical reorganization.2,3Chen
et al1applied hot/cold packs on acute stroke patients and
found improvement on UE motor and sensory function.
However, the effect of TS on UE recovery in subacute or
chronic stroke patients remains unknown. We investigated
the effect of TS on the paretic UE at least 3 months after
stroke using custom-made thermal stimulators that provided
TS with stable temperatures.
hermal stimulation (TS)1recently has been developed to
promote upper extremity (UE) recovery in stroke pa-
Materials and Methods
This was an assessor-blinded, block-randomized, controlled study.
Participants were recruited from a university hospital. The inclusion
criteria were: (1) first-ever unilateral stroke; (2) stroke onset ?3
months and ?3 years; (3) ability to follow verbal instructions; (4)
age between 18 and 80 years; and (5) ability to sit on a chair for ?30
minutes and move paretic hand away from thermal therapeutic pad
independently, with and without the assistance of the nonparetic
hand. The exclusion criteria were: (1) musculoskeletal or cardiac
disorders that could interfere with experimental tests; (2) diabetic
history or sensory impairment attributable to peripheral vascular
disease or neuropathy; (3) skin injuries at the sites of stimulation; and
(4) contraindication of heat or ice application.
Thirty-one participants were recruited and they signed informed
consent. Eight were excluded because of ineligibility (n?6) and
refusal (n?2). Eligible participants were allocated randomly to either
the experimental group or the control group. All participants were
assessed by a physical therapist blinded to group allocation.
The research protocol was approved by the ethics committees.
This study is registered at ClinicalTrials.gov (NCT01078727).
All participants received regular outpatient rehabilitation (3 times
per week) in the study periods. Each session of the rehabilitation
included 1 hour of physical therapy and 1 hour of occupational
therapy. The experimental group received an additional UE-TS
protocol for 30 minutes (3 times per week for 8 weeks). The control
group received the same TS protocol on the lower extremity.
Participants in the experimental group were comfortably seated
with their hands placed on a table. Two thermal stimulators and two
therapeutic pads (Model B401L; Firstek Scientific Co) were used to
Received June 15, 2010; accepted June 29, 2010.
From Department of Physical Medicine and Rehabilitation (H.C.W., S.M.L.), Department of Physical Medicine and Rehabilitation (Y.C.L.), E-Da
Hospital, Kaohsiung, Taiwan; Department of Physical Therapy, I-Shou University, Kaohsiung, Taiwan; Department of Physical Therapy (M.J.H., J.H.L.),
College of Health Science, and Department and Graduate Institute of Neurology, College of Medicine, Kaohsiung Medical University, Kaohsiung,
Taiwan; School of Occupational Therapy (C.L.H.), College of Medicine, National Taiwan University, and Department of Physical Medicine and
Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan.
The statistical analysis was conducted by H.C. Wu and Dr J.H. Lin. The concept for the article was developed by Drs. J.H. Lin, M.J. Hsu, and C.L.
Hsieh. H.C. Wu, Y.C. Lin, and S.M. Liu acquired the data. All authors reviewed and made critical revisions to the final manuscript.
Correspondence to Jau-Hong Lin, Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, No 100, Shih-Chuan
1st Rd, Kaohsiung 807, Taiwan. E-mail firstname.lastname@example.org
© 2010 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.orgDOI: 10.1161/STROKEAHA.110.593673
by on August 28, 2010 stroke.ahajournals.orgDownloaded from
provide TS (hot or cold) at constant temperatures. Each thermal
stimulator was connected to a thin (1-mm) and flexible TS thera-
peutic pad (38?56 cm) in the closed-loop water system. The
temperature of the hot-pad surface was stable (46°C–47°C). That of
the cold-pad surface was also stable, ranging from 7°C to 8°C. The
therapeutic pad was wrapped around the paretic hand and distal arm
in the UE-TS protocol. In the TS protocol on lower extremity, the
therapeutic pad was wrapped around the distal lower leg and the
Intensities for thermal pain were chosen based on participants’
perceived pain thresholds and pain perception. Participants were
informed of possible adverse effects and were instructed to rate their
discomfort using a 10-cm visual analog scale ranging between 0 (no
pain) and 10 (maximum tolerable pain). During the development of
discomfort (visual analog scale score ?7), participants were encour-
aged to actively move their paretic hands away from the stimuli or to
generate a reflex. To induce voluntary/reflexive movement after TS,
ceiling durations of heating and cooling stimulation were limited to
15 seconds and 30 seconds, respectively. During TS intervention on
UE, the heating pad was put on the paretic hand 10 times, interleaved
with 30-second pauses. Participants were encouraged to withdraw or
move the paretic hand from the heating pad when discomfort
occurred or after 15 seconds of stimulation. During the 30-second
pause period, participants were encouraged to perform voluntary
paretic wrist and elbow extensions. After 10 occurrences of heating
stimulation, the cold stimulation procedure began. A session of TS
entailed 2 alternate cycles of heat and cold stimulation.
Primary outcome variables were the UE subscale of the Stroke
Rehabilitation Assessment of Movement and the Action Research
Arm Test. Secondary outcome variables were the Modified Ash-
worth Scale, the lower extremity subscale of the Stroke Rehabilita-
tion Assessment of Movement, and the Barthel Index. All outcome
measures were administered at baseline, week 8 (after treatment),
and week 12 (follow-up).
Repeated-measures analyses of variance followed by post hoc
analysis were used to analyze the results. The change score of each
measure between both groups was examined with Mann-Whitney U
All 23 participants completed the study. No adverse events
(burns or pain) were reported. We found no significant
differences between 2 groups at baseline (Table 1).
The interaction parameter (“time by group”) was signifi-
cant for the score on the UE subscale of the Stroke Rehabil-
itation Assessment of Movement, Action Research Arm Test,
and Modified Ashworth Scale of elbow flexors and wrist
flexors (P?0.05; Table 2).
The experimental group displayed greater improvements
on the scores of the UE subscale of the Stroke Rehabilitation
Assessment of Movement and Action Research Arm Test
than did the control group at week 8 (after treatment), with a
significant between-group difference (P?0.05). At follow-up
examination, a significant improvement in the experimental
group as compared to the control group was observed on the
UE subscale of the Stroke Rehabilitation Assessment of
of the Participants*
Demographic and Clinical Characteristics
Months since stroke onset
Type of stroke, ischemia/
Paretic side, left/right
Brunnstrom stage of proximal
part of UE
Brunnstrom stage of distal
part of UE
Brunnstrom stage of LE
MAS, affected elbow flexors
MAS, affected wrist flexors
Barthel Index (0–20)
*All values are mean?SD.
†Evaluated by means of ?2test for categorical variable, by means of
independent t test for continuous variables, and by means of the Mann-Whitney
U test for ordinal variables.
ARAT indicates Action Research Arm Test; LE, lower extremity; LE-STREAM,
lower-limb subscale of the Stroke Rehabilitation Assessment of Movement;
MAS, Modified Ashworth Scale; NIHSS, National Institutes of Health Stroke
Scale; UE, upper extremity; UE-STREAM, upper-limb subscale of the Stroke
Rehabilitation Assessment of Movement.
Table 2.Outcomes in the Experimental and Control Groups
Experimental 14.8?16.9 24.8?20.8 25.3?20.2 ?0.001*
Control12.2?17.3 14.7?18.8 16.7?18.4
Control 2.1?1.2 2.0?1.3
Experimental 9.2?5.5 11.0?5.3
Experimental 15.8?2.5 17.4?2.6
ARAT indicates Action Research Arm Test; LE, lower extremity; LE-
STREAM, lower extremity subscale of the Stroke Rehabilitation Assessment
of Movement; MAS, Modified Ashworth Scale; UE, upper extremity;
UE-STREAM, upper-extremity subscale of the Stroke Rehabilitation Assess-
ment of Movement.
*Values are presented as mean?SD. P are the result of the general linear
repeated-measures model. Bonferroni step-down correction was applied to
adjust for the significance level in multiple comparisons.
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Movement and Modified Ashworth Scale of elbow flexors
A “plateau phase” of UE recovery may have been reached at
3 months after stroke.4Our results indicate that an additional
UE-TS protocol could provide further improvement in motor
function of UE than those in the control group after 3 months
TS not only provides somatosensory stimulation but also
uses the forced-use strategy to provoke volitional/reflexive
motor activity. Although the mechanism of the effect of TS
on stroke patients remains unknown, it has been proposed that
somatosensory stimulation may induce plasticity in stroke
patients.5Further studies are needed to investigate the under-
lying mechanisms responsible for the effects of TS on UE
TS was developed as a low-cost and practicable interven-
tion. Previously, TS was provided through general hot/cold
packs, but it was difficult to provide constant temperature
stimulation and avoid tissue damage. In this study, we used
thermal stimulators to provide stable TS. No adverse events
were reported by the patients. Therefore, TS appears to be a
safe intervention for stroke patients. However, potential
complications during TS may form barriers to compliance. In
future studies, optimal therapeutic parameter settings must be
established based on safety and efficacy, namely temperature
settings, frequency, and intensity of TS.
The experimental group showed greater improvements in
the spasticity of elbow and wrist flexors after 8 weeks of TS;
forced use of the paretic hand was a possible reason.
However, further studies are needed to determine the effect of
TS on spasticity reduction.
Three limitations are noted. First, we did not investigate
the effect of TS on somatosensory recovery. Additional
studies are required to explore the effects of TS on sensory
functions, including pain thresholds and cortical representa-
tions. Second, we did not include patients older than 80 years
because of safety concerns. Third, the sample size of this
study was small; therefore, the generalizability of our results
is limited. A large-scale trial is necessary to explore the best
dose–response characteristics of TS.
Sources of Funding
This study was supported by research grants from the National
Science Council (NSC 96-2314-B-037-028) and the National Health
Research Institutes (NHRI-EX99-9907PI) in Taiwan.
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Table 3. Change From Baseline of the Outcome Measures
Outcome MeasuresControl Experimental
Values are presented as mean?SD.
Within group: *P?0.05, †P?0.01, when compared with baseline.
Between groups: ‡P?0.05, §P?0.01, when compared with the control
Bonferroni step-down correction was applied to adjust for the significance
level in multiple comparisons.
ARAT indicates Action Research Arm Test; LE-STREAM, lower extremity
subscale of the Stroke Rehabilitation Assessment of Movement; MAS, Modified
Ashworth Scale; UE, upper extremity; UE-STREAM indicates upper-limb sub-
scale of the Stroke Rehabilitation Assessment of Movement.
Wu et alThermal Stimulation on Motor Recovery
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