Effects of Mirror Therapy on Motor and Sensory Recovery in Chronic Stroke A Randomized Controlled Trial (2)

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ORIGINAL ARTICLE
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the patient the illusion of which inputs are perceived through the
affected limb behind the mirror. Substantial evidence has
demonstrated the immediate efficacy of MT on motor recovery in
University (grant no. EMRPD1B0371) in Taiwan.
No commercial party having a direct financial interest in the results of the research supporting
this article has or will confer a benefit on the authors or on any organization with which the authors
are associated.
0003-9993/13/$36 - see front matter ª 2013 by the American Congress of Rehabilitation Medicine
http://dx.doi.org/10.1016/j.apmr.2013.02.007
Archives of Physical Medicine and Rehabilitation
journal homepage: www.archives-pmr.org
Archives of Physical Medicine an
Ching-Yi Wu, ScD, OTR,a,b Pai-Chuan Huang, ScD, OTR,a Yu-Ting Chen, MS, OT,a
Keh-Chung Lin, ScD, OTR,c,d Hsiu-Wen Yang, MS, OTe
From the aDepartment of Occupational Therapy and Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University,
Taoyuan; bHealthy Aging Research Center, Chang Gung University, Taoyuan; cSchool of Occupational Therapy, College of Medicine, National
Taiwan University, Taipei; dDivision of Occupational Therapy, Department of Physical Medicine and Rehabilitation, National Taiwan University
Hospital, Taipei; and eDivision of Occupational Therapy, Department of Physical Medicine and Rehabilitation, Zhongxiao Branch of Taipei City
Hospital, Taipei, Taiwan.
Abstract
Objective: To compare the effects of mirror therapy (MT) versus control treatment (CT) on movement performance, motor control, sensory
recovery, and performance of activities of daily living in people with chronic stroke.
Design: Single-blinded, randomized controlled trial.
Setting: Four hospitals.
Participants: Outpatients with chronic stroke (NZ33) with mild to moderate motor impairment.
Interventions: The MT group (nZ16) received upper extremity training involving repetitive bimanual, symmetrical movement practice, in
which the individual moves the affected limb while watching the reflective illusion of the unaffected limb’s movements from a mirror. The CT
group received task-oriented upper extremity training. The intensity for both groups was 1.5 hours/day, 5 days/week, for 4 weeks.
Main Outcome Measurements: The Fugl-Meyer Assessment; kinematic variables, including reaction time, normalized movement time,
normalized total displacement, joint recruitment, and maximum shoulder-elbow cross-correlation; the Revised Nottingham Sensory Assessment;
the Motor Activity Log; and the ABILHAND questionnaire.
Results: The MT group performed better in the overall (PZ.01) and distal part (PZ.04) Fugl-Meyer Assessment scores and demonstrated
shorter reaction time (PZ.04), shorter normalized total displacement (PZ.04), and greater maximum shoulder-elbow cross-correlation (PZ.03).
The Revised Nottingham Sensory Assessment temperature scores improved significantly more in the MT group than in the CT group. No
significant differences on the Motor Activity Log and the ABILHAND questionnaire were found immediately after MT or at follow-up.
Conclusions: The application of MT after stroke might result in beneficial effects on movement performance, motor control, and temperature
sense, but may not translate into daily functions in the population with chronic stroke.
Archives of Physical Medicine and Rehabilitation 2013;94:1023-30
ª 2013 by the American Congress of Rehabilitation Medicine
Among people who have experienced a stroke, 55% to 75% have
a paretic arm that causes motor impairments1 and experience
difficulty in incorporating the affected hand into their activities.2
Although studies have shown that novel interventions, such
as robotic-assisted training3 and constraint-induced movement
therapy,4 promote motor recovery, these interventions are often
costly and labor intensive, consequently limiting their imple-
mentation on a larger scale.5,6
Mirror therapy (MT) may be a suitable alternative because of
its low cost and simplicity.5,7 In MT, the patient sits in front of
a mirror placed in the midsagittal plane. When looking into the
mirror, the patient sees the mirror reflection of the intact limb as if
it were the affected one. The movement of the intact limb gives
Supported in part by the National Health Research Institutes (grant nos. NHRI-EX101-9920PI
and NHRI-EX101-10010PI), the National Science Council (grant nos. NSC-100-2314-B-002-008-
MY3 and NSC 99-2314-B-182-014-MY3), and the Healthy Aging Research Center at Chang Gung
Effects of Mirror Therapy on Mo
Chronic Stroke: A Randomized C
r and Sensory Recovery in
ntrolled Trial
d Rehabilitation 2013;94:1023-30
people with stroke.8,9 Enhanced performance is often measured by
clinical evaluations, such as the Fugl-Meyer Assessment
(FMA),5,7,9,10 or self-report measures of daily function, such as
the Motor Activity Log (MAL).11 These clinical evaluations,
however, do not assess aspects of motor control that may be
important for understanding the motor learning mechanisms
responsible for task improvement.12 Some have proposed that the
visual illusion during MT generates positive feedback to the motor
cortex and might remodulate cortical mechanisms of sensation and
movement.11,13-18 How the possible cortical changes influence
recovery, and daily function more than the control treatment (CT).
Design
This study was a single-blinded, randomized controlled trial with
pretest, posttest, and follow-up assessments (fig 1). Participants
were randomized by stratifying by the lesion side and motor
impairment level (FMA-UE scores between 26 and 40 vs between
40 and 66).28 A set of numbered envelopes was prepared for each
stratum that contained cards indicating the allocated group. When
a new eligible participant was registered, an envelope was
randomly extracted and the relevant therapist was informed of the
group allocation. Two certified occupational therapists, blinded to
the allocation of each subject, conducted the examinations before
the first treatment, immediately after treatment, and at about
6 months after the last treatment.
Interventions
The intervention was conducted within the regularly scheduled
occupational therapy sessions, and all other interdisciplinary
rehabilitation proceeded as usual. The primary investigators
trained 5 certified occupational therapists to ensure consistent
treatment protocols. Treatment intensity, which was matched for
both groups, was 1.5 hours/day, 5 days/week, for 4 weeks.
Mirror therapy
In each session, participants received 60 minutes of MT, fol-
lowed by 30 minutes of task-oriented functional practice. During
1024 C-Y Wu et al
We also hypothesized that the positive effects on ADL would be
retained at 6 months after MT.
Methods
Participants
From 4 different hospitals, we recruited 33 participants who lived
at home after stroke (table 1). The inclusion criteria were as
follows: (1) a first-ever unilateral ischemic or hemorrhagic cere-
brovascular accident with onset of more than 6 months; (2) mild to
moderate motor impairment (total FMA-UE scores of 26e56)28-30;
(3) mild spasticity in all joints of the affected limb (Modified
Ashworth Scale score<3)31; and (4) sufficient cognitive ability to
follow instructions (Mini-Mental State Examination score�24).32
The exclusion criteria were as follows: (1) participation in
another drug or experimental rehabilitation project within 6 months;
(2) serious vision or visual perception impairments (eg, neglect and
poor visual field) as assessed by the National Institutes of Health
Stroke Subscales33; and (3) severe neuropsychologic, neuromus-
cular, or orthopedic disease. The investigational review board of
List of abbreviations:
ADL activities of daily living
CT control treatment
FMA Fugl-Meyer Assessment
MAL Motor ActivityLog
MT mirror therapy
rNSA Revised Nottingham Sensory Assessment
UE upper extremity
motor control has not been studied.
To address themotor controlmechanism, kinematic analyses can
be used to detect the spatial and temporal characteristics of upper
extremity (UE) movements. Kinematic information, including
movement timing, displacement, andmultijoint coordination,might
help us understand whether a true increase occurs in skill12,19-23 and
reflect the possible MT-induced reorganization of the brain.24-26
Given that the visual illusion of MTmight modulate the primary
somatosensory cortex,MTmay facilitate sensory recovery.19,27 One
study10 has reported a positive effect of MT on light touch. In
addition, the benefits of MT on activities of daily living (ADL) are
not yet conclusive.8 Moreover, few studies have reported that MT
has prolonged effects after 6 months.8 The limited evidence that
exists suggests that further studies are needed regarding the effects
of MT on sensory recovery and ADL immediately after an inter-
vention and at follow-up.6,10
From this background, we aimed to examine the effects of MT
on motor and sensory recovery. We hypothesized that MT would
improve motor performance, motor control strategies, sensory
each participating site approved the study protocol, and participants
provided informed consent. Twelve participants dropped out of the
study owing to scheduling difficulties at 6-month follow-up.
Table 1 Characteristics of study participants (nZ33)*
Variable MT (nZ16) CT (nZ17) Statisticy P
Sex (n) 0.01 .91
Male 11 12
Female 5 5
Age (y) 54.77�11.66 53.59�10.21 �0.31 .76
Side of brain
lesion (n)
0.26 .61
Right 8 10
Left 8 7
Stroke type, n (%) 0.05 .83
Hemorrhagic 6�37.5 7�41.2
Ischemic 10�62.5 10�58.8
Months after stroke
onset
19.31�12.57 21.88�15.55 0.52 .60
MMSE score 29.00�1.00 28.06�1.98 �1.65 .11
Years of education 12.06�4.54 11.79�3.50 �0.19 .85
NIHSS score 1.20�1.15 1.53�1.55 0.21 .50
FMA total score 45.94�8.91 44.41�10.69 �0.44 .66
Abbreviations: MMSE, Mini-Mental State Examination; NIHSS, National
Institutes of Health Stroke Scale.
* Continuous data are shown as mean � SD and categorical data as
indicated.
y Statistic associated with the c2 test or the Fisher exact test for
categorical variables and with the analysis of variance for continuous
variables.
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ndo
at
i
ligib
Mirror therapy on motor control 1025
A
llo
c
Pr
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, p
os
ttr
ea
tm
en
t 
te
st
s 
an
d
in
te
rv
en
tio
n
Mirror therapy (MT)
(n=16) 
Pretreatment test, MT 
intervention, and 
posttreatment test
MT group (n=16)
Ra
En
ro
llm
en
t
on
Potentially e
the MT training (see fig 2 for setting), participants were
instructed to look at the reflection of the unaffected hand in the
mirror as if it were the affected hand and perform bilateral
symmetrical movements as much as possible. The activities
consisted of (1) transitive movements, such as fine motor tasks
of squeezing sponges, placing pegs in holes, or flipping a card;
(2) gross motor tasks of reaching out to touch a switch or
keyboard; and (3) intransitive movements, including the distal
part movement of wrist repetitive extension-flexion or finger
opponent and the proximal part movement of forearm pronation-
supination.
Control treatment
The CT provided 90 minutes of traditional therapeutic activities
on the basis of task-oriented treatment principles. Functional tasks
were selected in accord with the abilities of the participants. The
CT focused on improving motor control skills in the affected UE,
coordination, and unilateral and bilateral fine motor tasks as well
as enhancing static and dynamic standing and sitting, balance, and
compensatory practice on functional tasks.
MT group follow-up
6 months later
5 lost to follow-up due to 
scheduling difficulties
(n=11)
Fo
llo
w
-u
p
Analyzed
A
na
ly
sis
Fig 1 Flow chart shows enrollment of patients and completion of study a
www.archives-pmr.org
Control treatment (CT)
(n=17)
Pretreatment test, CT 
intervention, and 
posttreatment test
CT group (n=17)
Excluded (n=229)
Did not meet inclusion criteria (n=207)
Declined to participate (n=22)
mized (n= 33)
le participants (n=262)
Outcome measures
Primary outcome measures: motor performancedFMA-UE
assessment
The FMA30 uses a 3-point ordinal scale to assess the level of
sensorimotor function in the affected UE. We used only the UE
motor function items. The maximum total motor score is 66,
with higher scores indicating better motor recovery. The total
motor scores were divided into the proximal part (shoulder/
elbow/forearm and coordination/speed) and the distal part (wrist
and hand). The FMA has high intrarater and interrater
reliability.29
Primary outcome measures: motor performancedkinematic
analysis
The participant was asked to press a desk bell while sitting on
a chair with his/her trunk restrained to the chairback. The bell was
positioned at a distance of 90% of the arm length (from the
acromion to the third fingertip) along the participant’s midsagittal
plane. If the patient’s maximum reaching distance was less than
the functional arm length, the distance was adjusted to the
CT group follow-up
6 months later
7 lost to follow-up due to 
scheduling difficulties
(n=10)
Analyzed
ccording to the Consolidated Standards of Reporting Trials statement.
1026 C-Y Wu et al
maximum reachable distance. After a practice trial, the participant
performed the task 3 times for data collection.
A 7-camera motion-analysis system (VICON MXa) was linked
to a personal computer to capture the movements of markers that
were placed on the acromion, middle of the humerus, the lateral
epicondyle, the styloid process of the ulna and radius, and the index
nail of the affected side. Movements were recorded at 120Hz and
digitally low-pass filtered at 5Hz using a second-order dual-pass
Butterworth filter.Movement onsetwas defined as the timewhen the
tangential wrist velocity rose 5% above the peak value for each trial.
Movement offset was defined as the bell being pressed and was
identified by the digital signal connected to the computer.
An analysis program coded by LabVIEWb language was used
to process the kinematic data. The variables collected were reac-
tion time, normalized movement time, normalized total displace-
Fig 2 In the intervention setup for mirror therapy, the participant
looks at the reflection of the unaffected hand in the mirror as if it
were the affected hand.
ment, joint recruitments (ie, normalized shoulder flexion,
normalized elbow extension, and normalized maximum shoulder
abduction angle), and maximum shoulder and elbow cross-
correlation. Because the task distance varied across participants,
values were normalized as needed.
Reaction time and normalized movement time represent the
temporal efficiency of movement. Reaction time is defined by the
interval from the start signal to movement onset, and normalized
movement time is the interval between the movement onset and
offset. Normalized total displacement, indicating the spatial effi-
ciency, refers to the path of the index finger in a 3-dimensional
space. Joint recruitment is defined as the change of the joint from
the beginning to the end of the movement. The maximum shoulder
and elbow cross-correlation represents the maximum similarity of
the time-angle waveforms of shoulder and elbow movements as
a function of a time-lag applied to the initiation of elbow move-
ment. Higher values of cross-correlation indicate a better interjoint
coordination between the shoulder and elbow.34,35
Secondary outcome measures: sensory and ADL
functionsdRevised Nottingham Sensory Assessment
The Revised Nottingham Sensory Assessment (rNSA) examinessensation impairment using a 3-point scale (0, absent; 1, impaired;
2, normal), with a total score of 48. The tactile subtest, including
light touch, temperature, pinprick, pressure, tactile localization,
and bilateral simultaneous touch, was administered to the affected
shoulder, elbow, wrist, and hand. Higher scores represent better
sensory function. The rNSA has good intrarater and interrater
reliability.36 Only those participants who scored less than 48
points at pretest, indicating sensation impairments, were included
in the data analysis.
Secondary outcome measures: sensory and ADL
functionsdMAL and ABILHAND
The MAL uses a semistructured interview to assess the amount of
use and quality of movement of the affected hand in 30 ADL.
Each item is rated from 0 to 5 points, and higher scores indicate
better performance. The test has good internal consistency, inter-
rater reliability, and construct validity.37
The ABILHAND questionnaire is a subjective measure
examining the participant’s difficulty in performing 23 activities
that require bimanual manipulation by using a questionnaire with
a 3-point response scale (0, not at all; 1, only partially or with
great difficulty and slowly; 2, fully and easily), with a maximum
score of 46. The Rasch reliability, responsiveness, and construct
validity are high in people with stroke.38
Statistical analysis
Data were analyzed with IBM SPSS 19.0 software.c Analysis of
covariance was used to control the variance in the pretest scores.
The pretest score was the covariate, group was the independent
variable, and posttest or follow-up score was the dependent vari-
able. To index the magnitude of group differences in performance,
h2ZSSb/SStotal was calculated for each outcome variable.
39
A large effect is represented by an h2 of at least .14, a moderate
effect by .06, and a small effect by .01.40 The alpha level was set
to .05. One main point of the present study was to demonstrate the
feasibility of adopting kinematic analysis in MT efficacy research
and to examine the efficacy at the kinematic parameter level. The
sample size of 16 or 17 in 1 group was considered appropriate for
the randomized controlled trial at the demonstration-of-concept
stage, such as the current study.41 No multiple testing correc-
tions were made to control type II errors,42 given that the nature of
this study was to establish a knowledge base for a novel
intervention.43
Results
Participant characteristics
The baseline demographic and clinical characteristics of the
participants in the MT and CT groups did not differ significantly
(see table 1). No adverse events were reported.
Primary outcome measures: motor performance and
kinematic characteristics
The results of the FMA and kinematic variables (table 2) showed
significant and large to moderate effects favoring the MT group on
the FMA total (F2,31Z6.32, PZ.009, h
2Z.17) and distal part
(F2,31Z3.25, PZ.041, h
2Z.10) scores. Kinematic results dis-
played significant and large effects favoring MT on reaction time
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Table 2 Descriptive and inferential statistics for primary outcome measures: FMA and kinematic analysis
Variable
Pretreatment Posttreatment ANCOVA
MT (nZ16) CT (nZ17) MT (nZ16) CT (nZ17) F P* h2y
FMA
Proximal part 31.13�3.20 30.94�4.48 34.19�3.31 33.18�3.54 2.10 .08 .07
Distal part 14.81�6.52 13.47�7.53 17.06�5.65 14.71�7.49 3.25 .04z .10
Total 45.94�8.91 44.41�10.69 51.25�8.14 47.88�9.75 6.32 .01z .17
Kinematic data
Reaction time (s) 0.47�0.10 0.41�0.13 0.41�0.11 0.42�0.16 3.45 .04z .11
Normalized
Movement time (s/mm) 0.009�0.006 0.006�0.002 0.007�0.018 0.006�0.007 1.77 .10 .06
Total displacement (mm/mm) 2.04�0.83 1.67�0.38 1.70�0.54 1.70�0.57 3.21 .04z .10
Shoulder flexion (deg/mm) 0.15�0.10 0.16�0.08 0.14�0.04 0.16�0.04 0.84 .18 .03
Elbow extension (deg/mm) 0.10�0.06 0.10�0.05 0.12�0.06 0.13�0.05 0.23 .32 .01
Maximum
Shoulder abduction (deg/mm) 0.17�0.100 0.15�0.08 0.13�0.06 0.15�0.07 2.80 .05 .09
Shoulder-elbow cross-correlation 0.72�0.17 0.71�0.16 0.79�0.13 0.69�0.16 3.96 .03z .12
NOTE. Values are mean � SD or as otherwise indicated.
Mirror therapy on motor control 1027
(F2,31Z3.45, PZ.037, h
2Z.11), normalized total displacement
(F2,31Z3.21, PZ.042, h
2Z.10), and maximum cross-correlation
between the shoulder and elbow (F2,31Z3.96, PZ.029, h
2Z.12).
Secondary outcome measures: sensory and ADL
functions
The Revised Nottingham Sensory Assessment
The MT group showed nonsignificant but moderate to large
positive effects on overall tactile scores (F2,12Z1.86, PZ.100,
h2Z.14; table 3) of the rNSA. The scores on the subscales showed
a significant and large effect on temperature sensory recovery in
Abbreviation: ANCOVA, analysis of covariance.
* One-tailed P value.
y h2ZSSb/SStotal.
z P<.05.
favor of the MT group (F2,12Z3.71, PZ.040, h
2Z.25).
MAL and ABILHAND at posttreatment and follow-up
No significant group differences were found on the MAL and
ABILHAND in posttreatment and follow-up (table 4).
Table 3 Descriptive and inferential statistics for the rNSA
Variable
Pretreatment
MT (nZ8) CT (nZ6)
Revised NSA
Light touch 3.75�3.73 5.50�2.81
Temperature 2.00�2.33 2.50�1.64
Pinprick 4.88�3.48 6.67�3.27
Pressure 5.50�3.12 7.33�1.21
Tactile localization 3.38�3.89 5.83�2.64
Bilateral simultaneous touch 3.75�3.41 5.83�2.79
Tactile total 23.25�17.87 33.67�12.04
NOTE. Values are mean � SD or as otherwise indicated.
Abbreviations: ANCOVA, analysis of covariance; NSA, Nottingham Sensory Ass
* One-tailed P value.
y h2ZSSb/SStotal.
z P<.05.
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Discussion
Our findings were partially consistent with our hypotheses. MT
after stroke resulted in beneficial effects on movement perfor-
mance and motor control, and patients with sensory impairments
in the MT group experienced a greater temperature sensation
recovery than patients in the CT group. However, patients in the
MT group did not demonstrate greater improvements on subjec-
tive ADL performance assessments immediately after intervention
or at 6-month follow-up.
In accord with previous studies,5,9,10 we found greater
improvements in movement performance after MT than after CT,
as measured by the FMA. The effects might result from cortical
reorganization.19 MT could provide “proper visual input” and,
perhaps, “substitutes” for absent or reduced proprioceptive input
from the affected body side.44 MT might also facilitate
self-awareness and spatial attention by activating the superior
Posttreatment ANCOVA
MT (nZ8) CT (nZ6) F P* h2y
5.88�3.40 6.50�1.38 0.07 .40 .01
4.63�3.34 2.50�1.98 3.71 .04z .25
6.50�2.78 7.50�0.84 0.06 .40 .01
7.38�1.06 7.00�2.00 2.63 .07 .19
5.63�2.67 5.83�3.13 0.53 .24 .05
5.88�3.00 5.83�3.13 2.24 .08 .17
35.88�15.14 35.17�10.65 1.86 .10 .14
essment.
after MT or at follow-up compared with CT. This finding is in
studies recruit 26 participants in each group to improve the chance
1028 C-Y Wu et al
temporal gyrus, precuneus, and the posterior cingulate cortex.45,46
Consequently, the experience during MT might help recruit the
premotor cortex or balance the neural activation within the
primary motor cortex toward the affected hemisphere to facilitate
motor improvements.46-48 Another finding in the present study is
that the improvement of the affected hand in distal motor func-
tiondbut not proximal motor functiondwas significantly greater
in the MT group. This is consistent with the findings of Dohle and
colleagues.10 The visual illusion input of the mirror reflection in
MT might especially activate the damaged hemisphere.18,49,50
Considering that the cortex of the damaged hemisphere relates
to distal movement control of the affected hand51,52 more than to
proximal control, MT might be more associated with motor
Table 4 Descriptive and inferential statistics forADL measures
Variable
Outcome ANCOVA
MT (nZ16) CT (nZ17) F P* h2y
MAL_AOU
Pretreatment 1.22�1.07 1.18�1.28
Posttreatment 1.49�1.08 1.62�1.36 0.904 .18 0.03
Follow-up 1.83�1.29z 1.62�1.19x 0.069 .40 0.004
MAL_QOM
Pretreatment 1.20�1.02 1.22�1.13
Posttreatment 1.61�1.13 1.58�1.07 0.119 .37 0.004
Follow-up 1.97�1.41z 1.78�1.27x 0.019 .45 0.001
ABILHAND
Pretreatment 36.69�12.94 31.24�14.21
Posttreatment 35.81�16.09 34.44�13.95 0.058 .41 0.002
Follow-up 44.55�12.62z 40.30�13.53x 0.039 .43 0.002
NOTE. Values are mean � SD or as otherwise indicated.
Abbreviations: ANCOVA, analysis of covariate; AOU, amount of use;
QOM, quality of movement.
* One-tailed P value.
y h2ZSSb/SStotal.
z MT group, nZ11.
x CT group, nZ10.
recovery in the distal part of the body.
Our findings through kinematic analyses are the first to quan-
tify the changes after MT at the motor control strategy level. As
mentioned, MT might induce cortical reorganization and the
results showed that shorter reaction time (more efficient in motor
preplanning), straighter arm movement (better spatial efficiency in
movement execution), and better shoulder-elbow coordination
occurred after MT. The findings indicated that MT promoted
normalized movement, consistent with a previous study.7
However, this previous evidence was through a subjective obser-
vation where patients showed improved coordination and fluidity
of movements during MT. The positive changes in kinematic
parameters we observed here extend the previous knowledge and
provide objective evidence of an ongoing motor learning process
toward regaining voluntary motor control after MT.24
In contrast, temporal efficiency of movement execution and
joint recruitments did not improve significantly more in the MT
group than in the CT group. One reason could be that we did not
stress movement speed in our treatment protocols. Furthermore,
the bell during the experimental reaching task was placed at 90%
arm length or the maximum reachable distance at pretest. The
distance at pretest was also used at posttest; thus, the task might
not have been challenging enough to probe potential gained joint
ranges after the intervention.
to 80%.57 Besides, our results may be applicable only to people
with mild to moderate motor impairment at the chronic stage of
stroke living at home. In addition, MT requires participants to
focus on perceiving the image in the mirror. We excluded people
who could not follow instructions (Mini-Mental State Examina-
tion score<24). However, we did not assess the extent to which
the participant focused on the mirror image during task practice.
Future research may address this compliance issue to study the
potential role of this factor in treatment success of MT.
Conclusions
This study first reports changes in motor control and presents
seminal findings on sensory outcome after MT. Our findings
suggest that in addition to positive effects on motor function, MT
might improve motor preplanning and spatial efficiency in
movement execution and multijoint coordination and have
promising effects on temperature sensation recovery.58 Future
research on MT might refine our current protocol to study patients
with sensory and perceptual deficits using a larger sample size
with varying characteristics. To optimize the effects of MT, there
is a need to explore the benefits of a hybrid intervention of MT
with task-oriented rehabilitation or home-based MT using tele-
rehabilitation technology to improve generalizability of the effects
of MT to contexts other than the clinic.
accord with the study of Michielsen et al46 and in disagreement
with others.6,7,11 The inconsistency could be the nature of
patients’ living settings and the control groups used. First, the
participants in the Yavuzer et al6 study lived in rehabilitation
centers, unlike our participants, who were outpatients living at
home. Our participants might have established a stable ADL
routine that was less likely to change over time.5 Second, the
Sathian et al7 study, which reported gains in ADL performance at
follow-up, was a case study without a comparison group.
Study limitations
The results, especially on the sensory recovery, should be
considered with caution because of the preliminary nature and size
of this study. A post hoc power analysis on the results of the total
tactile assessment revealed that we had a 30% chance to detect
a group difference with a type I error of .05. We suggest that future
Temperature sensation improved significantly more in the MT
group than in the CT group. The benefits could relate to multi-
modal neurons.7 Multimodal neurons in the posterior parietal and
premotor cortical areas respond to sensory stimuli, such as visual
input, as well as movement stimuli.53 The visual illusion of MT
could provide sensory inputs that might modulate the somato-
sensory cortex network and contribute to the recovery of soma-
tosensation.18,27,54,55 In addition, recovery of temperature and pain
sensation in patients with stroke usually precedes the recovery of
proprioception and light touch.56 MT in the present study might
have promoted temperature sensation first. Considering that our
protocol focused on motor training rather than sensory training,
the preliminary results on sensation are promising for further
investigation of the effects of MT focusing on specific
sensory training.
No significantly better effects on ADL were noted immediately
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Repair 2011;25:223-33.
Mirror therapy on motor control 1029
6. Yavuzer G, Selles R, Sezer N, et al. Mirror therapy improves hand
function in subacute stroke: a randomized controlled trial. Arch Phys
Med Rehabil 2008;89:393-8.
7. Sathian K, Greenspan AI, Wolf SL. Doing it with mirrors: a case study
of a novel approach to neurorehabilitation. Neurorehabil Neural
Repair 2000;14:73-6.
8. Thieme H, Mehrholz J, Pohl M, Behrens J, Dohle C. Mirror therapy
for improving motor function after stroke. Cochrane Database Syst
Rev 2012;(3):CD008449.
9. Lee MM, Cho H-Y, Song CH. The mirror therapy program enhances
upper-limb motor recovery and motor function in acute stroke
patients. Am J Phys Med Rehabil 2012;91:689-700.
10. Dohle C, Pu¨llen J, Nakaten A, Ku¨st J, Rietz C, Karbe H. Mirror
therapy promotes recovery from severe hemiparesis: a randomized
controlled trial. Neurorehabil Neural Repair 2009;23:209-17.
11. Cacchio A, De Blasis E, De Blasis V, Santilli V, Spacca G. Mirror
therapy in complex regional pain syndrome type 1 of the upper limb in
stroke patients. Neurorehabil Neural Repair 2009;23:792-9.
12. Krakauer JW. Motor learning: its relevance to stroke recovery and
neurorehabilitation. Curr Opin Neurol 2006;19:84-90.
13. Stevens JA, Stoykov MEP. Using motor imagery in the rehabilitation
of hemiparesis. Arch Phys Med Rehabil 2003;84:1090-2.
14. Ramachandran VS, Rogers-Ramachandran D, Cobb S. Touching the
phantom limb. Nature 1995;377:489-90.
Suppliers
a. Oxford Metrics Inc, 14 Minns Business Park, West Way,
Oxford OX2 0JB, UK.
b. National Instruments, Inc, 11500 N Mopac Expwy, Austin, TX
78759-3504.
c. IBM SPSS Statistics, Inc, 233 S Wacker Dr, 11th Fl, Chicago,
IL 60606.
Keywords
Activities of daily living; Motor skills; Rehabilitation; Sensation;
Stroke; Upper extremity
Corresponding author
Keh-Chung Lin, ScD, OTR, School of Occupational Therapy,
College of Medicine, National Taiwan University and Division of
Occupational Therapy, Department of Physical Medicine and Reha-
bilitation, National Taiwan University Hospital, 17, F4, Xu Zhou
Road, Taipei, Taiwan. E-mail address: kehchunglin@ntu.edu.tw.
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1030 C-Y Wu et al
www.archives-pmr.org
	Effects of Mirror Therapy on Motor and Sensory Recovery in Chronic Stroke: A Randomized Controlled Trial
	Methods
	Participants
	Design
	Interventions
	Mirror therapy
	Control treatment
	Outcome measures
	Primary outcome measures: motor performance—FMA-UE assessment
	Primary outcome measures: motor performance—kinematic analysis
	Secondary outcome measures: sensory and ADL functions—Revised Nottingham Sensory Assessment
	Secondary outcome measures: sensory and ADL functions—MAL and ABILHAND
	Statistical analysis
	Results
	Participant characteristics
	Primary outcome measures: motor performance and kinematic characteristics
	Secondary outcome measures: sensory and ADL functions
	The Revised Nottingham Sensory Assessment
	MAL and ABILHAND at posttreatment and follow-up
	Discussion
	Study limitations
	Conclusions
	Suppliers
	Keywords
	Corresponding author
	References