Finger soaking enhances effects of light touch in DCD
revealed that sensitivity to LT did not differ between
Tests 1 and 2 (p = 0.39), but was significantly greater
in Test 3 than Test 2 (p < 0.05). Lastly, there was no
significant Group × Sensitivity Assessment interaction
(F(2, 50) = 0.26, p = 0.52). Post-hoc tests revealed that
both groups showed a similar trend of changes in sensi-
tivity to LT across 3 tests: sensitivity to LT did not differ
between Tests 1 and 2 (for the DCD group, p = 0.33;
for the TDC group, p = 0.16), whereas sensitivity to LT
was significantly greater in Test 3 than in Test 2 (for
the DCD group, p < 0.05; for the TDC group, p < 0.05).
In addition, children with DCD expressed significantly
lower sensitivity to LT than TDC in Test 1 (p < 0.05),
Test 2 (p < 0.05) and Test 3 (p < 0.05).
Body sway
Fig. 4 depicts AP body sway in the NT, LT and LTAS
conditions for children with DCD and TDC. For the
DCD group, the mean AP sway was 0.81 ± 0.07 cm in
the NT condition, 0.63 cm (SD 0.06) in the LT condi-
tion, and 0.54 cm (SD 0.04) in the LTAS condition. For
the TDC group, the mean AP sway was 0.75 cm (SD
0.10) in the NT condition, 0.54 cm (SD 0.04) in the LT
condition, and 0.53 cm (SD 0.03) in the LTAS condition.
ANOVAs for AP body sway identified a main ef-
fect of Group (F(2, 50) = 54.47, p < 0.05, η 2 = 0.69),
showing that children with DCD had significantly
greater AP body sway than did TDC. In addition, the
results revealed a main effect of Touch Condition (F(2,
50) = 7.51, p < 0.05, η 2 = 0.24), showing that AP body
sway significantly differed among NT, LT and LTAS
conditions. Post-hoc tests revealed that AP body sway
was significantly greater in the NT than LT condition
Fig. 4. Mean body sway in anteroposterior (AP) direction in the no
fingertip touch (NT), light fingertip touch (LT), and light fingertip touch
after soaking in surfactant-water solution (LTAS) conditions for children
with developmental coordination disorder (DCD) (black triangles) and
typically developing children (TDC) (grey squares). Bars represent
standard errors. Daggers denote a significant difference between
experimental conditions. Asterisks denote a significance difference
between children with DCD and TDC.
221
(p < 0.05), as well as significantly greater in the LT than
LTAS condition (p < 0.05). Lastly, the results revealed a
Group × Touch Condition interaction (F(2, 50) = 4.12,
p < 0.05, η 2 = 0.08), implying that the effects of different
touch conditions (NT, LT and LTAS) on AP body sway
varied significantly for children with DCD and TDC.
Post-hoc tests revealed that, in the DCD group, AP
body sway was significantly greater in the NT than
LT condition (p < 0.05), as well as significantly greater
in the LT than LTAS condition (p < 0.05). However,
different results were obtained in the TDC group:
AP body sway was significantly greater in the NT
than LT condition (p < 0.05), whereas AP body sway
did not differ between the LT and LTAS conditions
(p = 0.14). In addition, children with DCD expressed
significantly greater AP body sway than TDC in both
the NT (p < 0.05) and LT conditions (p < 0.05), but not
in the LTAS condition (p = 0.10). No significant effects
were achieved for ML body sway data.
DISCUSSION
This study compared sensitivity to LT between children
with DCD and TDC, and investigated how changes/
increases in sensitivity to LT impact the effects of LT
on reducing body sway in both groups. Since no signifi-
cant differences in upper limb movement (finger, palm,
forearm, or upper arm) were detected between groups
and across different touch conditions, it was concluded
that the confounding effects of arm configuration were
not relevant in this study. The main findings are as fol-
lows: firstly, sensitivity to LT is impaired in children
with DCD compared with their cohorts; secondly, finger
soaking improved sensitivity to LT in both the DCD and
the TDC groups. Lastly, finger soaking enhances the
effects of LT on reducing body sway only for children
with DCD. These main findings are discussed below.
Our first hypothesis, that sensitivity to LT is lower in
children with DCD, was confirmed, since the present
data show that children with DCD have inferior sensi-
tivity to LT compared with TDC for both sensitivity to
LT tests 1 and 2. These results were comparable with
earlier findings that children with DCD have difficulty
with tactile localization and identification of stimuli
on the fingers (25, 26), implying that sensitivity to LT
affects children with DCD. Future studies are needed
to investigate the characteristics of sensitivity to LT
regarding various electrophysiological measurements
(i.e. changes in intracellular ion concentration, num-
bers of tactile-evoked potentials, and nerve conduction
velocity), to further clarify why children with DCD
have deficits in LT sensation. In short, this study pro-
vides initial empirical evidence for abnormal or lower
sensitivity to LT in children with DCD.
J Rehabil Med 51, 2019