Journal of Rehabilitation Medicine 51-4inkOmslag | Page 83

J Rehabil Med 2019; 51: 317–318
LETTER TO THE EDITOR
UPDATES AND COMMENTS ON: INFLUENCE OF TRANSCUTANEOUS ELECTRICAL NERVE
STIMULATION ON SPASTICITY, BALANCE, AND WALKING SPEED IN STROKE PATIENTS: A
SYSTEMATIC REVIEW AND META-ANALYSIS
We read with interest the recent article by Lin et al.,
entitled “Influence of transcutaneous electrical nerve
stimulation on spasticity, balance, and walking speed in
stroke patients: a systematic review and meta-analysis”
(1). In this review the authors included 7 studies ana-
lysing the effect of transcutaneous electrical nerve
stimulation (TENS) (3–9).
It is important to note that there is a limited number
of studies on the presented topic; thus, this review
appears to be very important for both clinicians and
researchers. However, the article has several issues
that need to be addressed. Some of these have already
been mentioned by Etoom (2), but we would like to
update the previous letter to the editor with the fol-
lowing issues.
The authors reported that “A TENS group was found
to significantly improve static balance with open eyes
(SMD = –1.26; 95% CI = –1.83 to –0.69; p <0.0001;
Fig. 4) and closed eyes (SMD = –1.74; 95% CI = –2.36
to –1.12; p < 0.00001; Fig. 5), as well as walking speed
(SMD = 0.44; 95% CI = 0.05 to 0.84; p = 0.03; Fig. 6)”.
However, Fig. 6 shows that the control group results
were significantly better than the TENS group results,
while the authors claimed that better results were ob-
tained by the TENS group. This affirmation is repeated
several times in the discussion section. Furthermore,
from the studies included in this analysis (3–5), the
study by Burridge et al. (3) analysed changes in
TENS + PT
Study or Subgroup Mean
Ng 2007 0.682
Park 2014
Mean Difference
SD Total Weight
IV, Fixed, 95% CI
0.345 21 0.577 0.298 20 33.2% 0.11 [-0.09, 0.30]
0.5289 0.1743 15 0.494 0.205 14 66.8% 0.03 [-0.10, 0.17]
36 34 100.0% 0.06 [-0.06, 0.17]
Total (95% CI)
Heterogeneity: Chi = 0.32, df = 1 (P = 0.57); I = 0%
Mean Difference
IV, Fixed, 95% CI
-0.5
-0.25
0
0.25
Favours [experimental] Favours [control]
Test for overall effect: Z = 1.00 (P = 0.32)
0.5
Analysis 1. Comparison of transcutaneous electrical nerve stimulation vs control group: effect on walking speed post intervention.
TENS
Study or Subgroup Mean
Ng 2007 0.629 0.284
Control
SD Total Mean
Total (95% CI)
Placebo + PT
SD Total Mean
walking speed through functional electrical stimulation
(FES) and not TENS. Thus, according to the authors’
inclusion criteria, this study should not be included in
meta-analysis. Furthermore, the study by Ng et al. (4)
showed that TENS combined with task-related training
(TRT) significantly improved gait velocity, but not in
the group of patients where TENS alone was applied.
Also, the number of patients analysed differs from
those stated in the study by Ng et al., and should be 19
for TENS group and 21 for the TENS+TRT group. Si-
milarly, the study conducted by Park et al. (5) analysed
the influence of TENS combined with therapeutic exer-
cises on gait speed, and not TENS alone. None of this
information was specified adequately by the authors
of this review. The meta-analysis of walking speed is
presented incorrectly; the authors adapted results from
follow-up assessment and compared them with those
obtained at the end of therapy presented in another
study. Therefore, we conducted a new meta-analysis
in order to update this information, considering both
TENS vs control group (Analysis 1) and TENS com-
bined with additional physiotherapy (PT) vs control
group, i.e. placebo combined with physiotherapy
(Analysis 2). Considering the same outcome measure,
we used the difference in means with a fixed effects
model for meta-analysis to measure the absolute dif-
ference between the mean value in the 2 groups and
to observe the mean change.
Mean Difference
SD Total Weight
IV, Fixed, 95% CI
19 0.639 0.241 20 100.0% -0.01 [-0.18, 0.16]
19 20 100.0% -0.01 [-0.18, 0.16]
Heterogeneity: Not applicable
Test for overall effect: Z = 0.12 (P = 0.91)
Mean Difference
IV, Fixed, 95% CI
-0.5
-0.25
0
0.25
0.5
Favours [experimental] Favours [control]
Analysis 2. Comparison of transcutaneous electrical nerve stimulation combined with additional physiotherapy (TENS + PT) vs placebo combined
with physiotherapy (Placebo + PT): effect on walking speed post intervention.
This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm
Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977
doi: 10.2340/16501977-2538