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extremity after stroke. One of the characteristics of
CCFES is that it requires active participation from
patients, and not merely electrical stimulation of the
paretic muscle or extremity. As described by Knutson
et al., “CCFES uses a control signal from the non-
paretic side of the body to regulate the intensity of
electrical stimulation delivered to the paretic muscles
of the homologous limb on the opposite side of the
body” (8). In separate studies, Knutson et al. (9) and
Shen et al. (10) compared the effectiveness of CCFES
and NMES in patients with sub-acute stoke, and found
greater improvements with CCFES. Nonetheless, its ef-
fectiveness in the early-phase (i.e. within 15 days) after
stroke is unclear. The aim of this study was therefore
to investigate the effectiveness of CCFES compared
with NMES on upper extremity function, particularly
WD, in patients with early-phase stroke.
MATERIAL AND METHODS
Subjects
Patients admitted to the Department of Neurology, Jiangsu
Province People’s Hospital, Nanjing, China, between March
and September 2015 were recruited to this study. All subjects
provided written informed consent prior to the study, and the
ethics committee of the First Affiliated Hospital of Nanjing
Medical University approved the study protocol.
Inclusion criteria were: (i) diagnosed with stroke using
computed tomography (CT) or magnetic resonance imaging
(MRI); (ii) stable vital signs 48 h post-stroke; (iii) single-side
injury; (iv) age 20–80 years; (v) within 15 days post-stroke; (vi)
Brunnstrom recovery stage of III or less; (vii) score of Fugl-
Meyer assessment (FMA) for upper extremity ≤ 22; and (viii)
no active WD detected.
Exclusion criteria were: (i) progressive stroke with non-stable
condition; (ii) stroke-like symptoms due to subdural haematoma,
tumour, encephalitis or trauma; (iii) unable to follow treatment
instructions due to severe cognitive and communication defi-
ciency; (iv) implanted with a pacemaker; and (v) no informed
consent (11).
Randomization
stimulators (Weisi Corporation, Nanjing, China) used in this
study delivered biphasic rectangular current pulses; the pulse
frequency was set at 35 Hz, and the pulse amplitude was set at 40
mA. The electrical stimulation intensity was set at a sustainable
level with full balanced WD with tetanic contraction.
In the CCFES group, 3 recording electrodes (4 × 4 cm) were
placed on the motor points of the forearm extensor muscles
(the ulnar margin of the extensor aspect of the forearm) on
the non-paretic side, while 2 stimulating electrodes (4 × 4 cm)
were attached on the paretic side (Fig 1b). For each patient, the
intensity of the electrical stimulation to WD of the paretic side
was determined by the strength of contralateral forearm extensor
muscles contraction. Subjects were asked to voluntarily extend
their unaffected wrist to 10% of ROM or less and maintain that
position without moving. The electromyography value of the
movement was then recorded. Meanwhile, the therapist adjusted
the electric intensity until the same degree of movement appea-
red on the paretic side. The intensity value was then recorded.
The same practice and recording process was also applied, with
the patients extending their unaffected wrist to 50% and 100%
of ROM. The electrical stimulation intensity that produced
balanced WD was determined empirically for each patient and
programmed into the stimulator.
The design and application of the stimulator was consistent
with the protocol reported by Knutson et al. (9). The stimulator
issued sound and light cues to inform the CCFES participants
when and for how long to attempt to perform WD. For the
NMES group, the stimulator was programmed to automati-
cally and repetitively ramp the pulse durations from minimum
to maximum in 1 s, maintain the stimulation at maximum for
several seconds, and then ramp down the stimulation in 1 s,
repeating this cycle at a rate that matched the sound and light
cue timing in the NMES group.
Study protocol
Eligible patients were randomly assigned to either the NMES
group or the CCFES group. Both groups received routine re-
habilitation (mainly proprioceptive neuromuscular facilitation
for 30 min/day) for the upper and lower extremities for 5 days
over a period of 2 weeks.
In addition to routine rehabilitation, patients in the NMES
group received neuromuscular electrical stimulation (2 20-
min sessions each day). Each session consisted of 48 15-s sets,
separated by 10 s of rest. The forearm extensor muscles were
stimulated by the NMES instrument to complete WD without
the patients’ active participation.
Patients were assigned to either the NMES
or the CCFES group based on a computer-
generated randomization list and allocation
(1:1) concealed by consecutively numbered,
sealed opaque envelopes. An envelope was
opened once a patient had consented to
participate in the trial, the administrator
then informed the doctor about the allocated
intervention regimen via phone calls.
Electrical stimulation system
In the NMES group, 2 stimulating electrodes
(4 × 4 cm) were placed at the motor points of
the forearm extensor muscles (specifically
the ulnar margin of the extensor aspect of
the forearm) to produce WD (Fig. 1a). The
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Fig. 1. Patients treated with different strategies. (a) The patient underwent neuromuscular
electrical stimulation (NMES) with the stimulator in Model I; (b) the patient underwent
contralaterally controlled functional electrical stimulation (CCFES) with the stimulator in
Model II.