Finger soaking enhances effects of light touch in DCD
219
(NT), light fingertip touch (LT), and light fingertip touch
after immersion in surfactant-water solution (LTAS)
conditions. The 3 conditions were presented in a block
DCD (n = 26) TDC (n = 26)
Mean (SD)
Mean (SD)
t
p-value
design, and the order of the blocks was pseudo-random.
Half of the children with DCD and TDC completed
Age, years
11.82 (0.46)
11.71 (0.50)
0.81
0.42
Height, cm
148.27 (8.80) 148.79 (9.01)
–0.21
0.83
the NT condition first, then the LT condition, with the
Weight, kg
48.63 (9.69)
46.55 (8.44)
0.82
0.41
remaining half in the reverse order. Note that, for all
MABC-2 percentile
1.77 (1.57)
78.73 (16.83) −23.11 < 0.01
participants, the LTAS condition was always adminis-
KBIT-2
107.58 (10.49) 109.62 (10.41) −0.70
0.49
tered last due to considerably slower recovery of skin
CTRS
50.35 (5.17)
48.23 (5.55)
1.42
0.16
sensitivity from surfactant-water solution immersion
EHI
93.27 (4.85)
94.19 (3.02)
–0.82
0.41
(approximately 30 min) (14), and thus was more likely
AP touch force in LT condition
0.34 (0.07)
0.36 (0.6)
0.51
0.48
ML touch force in LT condition
0.24 (0.09)
0.23 (0.04)
0.33
0.47
to influence subsequent test results.
VL touch force in LT condition
0.61 (0.07)
0.64 (0.08)
1.16
0.29
In each condition, children were requested to complete
AP touch force in LTAS condition
0.29 (0.10)
0.31 (0.06)
0.37
0.54
3 60-s trials with a barefoot shoulder-width stance on a
ML touch force in LTAS condition
0.22 (0.06)
0.21 (0.06)
0.30
0.49
force plate. In order to remove any possible influences
VL touch force in LTAS condition
0.68 (0.09)
0.60 (0.10)
2.67
0.11
of vision (20), participants had to hold the eyes shut and
DCD: developmental coordination disorder; TDC: typically developing children; MABC-
wear an eye mask. Heel and toe positions were marked
2: 2 nd edition of The Movement Assessment Battery for Children; KBIT-2: 2 nd edition
with tape on the force plate at the start of the first trial and
of The Kaufmann Brief Intelligence Test; CTRS: Conners’ Teacher Rating Scale; EHI:
Edinburgh Handedness Inventory; LT: light fingertip touch; LTAS: light fingertip touch
the foot placements were not allowed to be changed in
after soaking in surfactant-water solution; AP: anteroposterior. ML: mediolateral; VL:
each testing trial. To exclude the confounding effects of
vertical; SD: standard deviation.
different arm configurations (12), participants were asked
to maintain identical arm posture in all experimental con-
ditions (21, 22). In the NT condition, participants were
300 g (Touch Test, Stoelting Co., Wood Dale, IL, USA) by a
requested to hold their own non-dominant arm at the side of their
licensed and experienced physical therapist who was blinded
body, and the dominant elbow in 90° flexion, with the wrist in the
to the allocated groups of children. During the assessment,
neutral position with palm down, and index finger slight extended
participants were blindfolded and instructed to sit comfortably
(with all other fingers flexed) (Fig. 2, left). In the LT and LTAS
on a chair with their dominant hand resting on a table (palm
conditions, participants were requested to use the same prescribed
facing upward). The sequence of the assessment proceeded
from the smallest to the largest filament. The test was stopped
once participants had correctly identified a LT stimulus, and was
repeated 3 times to obtain a mean value. A greater minimum
detectable stimulus denotes less sensitivity to LT and vice versa.
The sensitivity to LT test was executed 3 times (for details, see
protocols), and this test was completed in approximately 2~2.5
min each time.
Table I. Basic data for children with developmental coordination disorder
(DCD) and typically developing children (TDC)
Light touch plate
The study used a customized force plate (5 × 5 cm) consisting
of load cells (LSB 200, Futek Advanced Sensor Technology,
Inc., Irvine, CA, USA) (attached to a tripod) that transduced
transverse and vertical force applied by the finger. The height
and position of the tripod was regulated so that, in experimental
conditions requiring the execution of a light fingertip touch,
participants could lightly contact the touch plate with the desi-
red arm configuration (for details, see protocols). Touch force
data were sampled at 1,000 Hz with Labview 2012 (National
Instruments, Austin, TX, USA).
Force plate
A force plate (model: ORP-WP-1000, Advanced Mechanical
Technology Inc., Watertown, MA, USA) was used to collect
kinetic data for all experimental conditions, from which the
centre-of-pressure position in both anteroposterior (AP) and
mediolateral (ML) axes was acquired with a sampling frequency
of 1,000 Hz. The COP was utilized in this study, as COP analysis
has been commonly applied in studies on standing postural
control and balance performance during the past 30 years (19).
Protocols
Fig. 1 illustrates the experimental protocols. Participants were
exposed to experimental conditions, including no fingertip touch
Fig. 1. Experimental protocols. DCD: developmental coordination
disorder; TDC: typically developing children; NT: no fingertip touch;
LT: light fingertip touch; LTAS: light fingertip touch after soaking in
surfactant-water solution.
J Rehabil Med 51, 2019