Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 15

C. Nikamp et al.
did not change EMG activity levels. Therefore, they
concluded that AFO use is safe, even for recently pa-
retic patients. It is not known whether AFO use over a
longer period of time after stroke has negative effects.
Furthermore, it is not known whether early or late
provision of AFOs post-stroke affects muscle activity.
The aim of this study was to determine the long-term
effects of AFO use on muscle activity of the TA muscle.
The primary aim was to determine whether AFO use
affects TA muscle activity over a period of 26 weeks
within subjects provided with AFOs early or delayed
after stroke. Secondly, between-group differences in
TA muscle activity were measured for early and de-
layed provision of AFOs. Thirdly, whether provision
of AFOs affects TA muscle activity within a single
measurement session was determined when walking
with and without AFOs.
In agreement with previous literature, it was hypo-
thesized that AFO use decreases TA muscle activity
during the swing phase, comparing walking with and
without AFOs within a measurement. However, it was
also hypothesized that TA muscle activity over time
would not be affected by AFO use, and it was not ex-
pected that timing of AFO provision would influence
the results.
METHODS
Study design
Study data were collected as part of a single-centre, randomized
controlled, parallel group study, which aimed to study the ef-
fects of different timing of provision of AFOs. The study was
approved by the medical ethics committee Twente, registered
in the “Nederlands Trial Register”, number NTR1930, and
followed the CONSORT guidelines (10). All subjects provided
written informed consent.
Subjects
Subjects were recruited by the main researcher between De-
cember 2009 and March 2014, follow-up continued until 2015.
Stroke subjects were recruited from the Roessingh Centre for
Rehabilitation in Enschede, the Netherlands. Inclusion criteria
were: (i) unilateral ischaemic or haemorrhagic stroke leading to
hemiparesis (single and first-ever stroke or history of previous
stroke with full physical recovery); (ii) minimum 18 years;
(iii) maximum 6 weeks post-stroke; (iv) receiving in-patient
rehabilitation care at inclusion; (v) able to follow simple verbal
instructions; (vi) indication for AFO use (i.e. abnormal initial
floor contact and/or problems with foot-clearance in swing
and/or impaired ability to take bodyweight through the paretic
lower limb in stance) determined by the treating rehabilitation
physician and physiotherapist. Exclusion criteria were: subjects
with severe comprehensive aphasia, neglect or cardiac, pulmo-
nary or orthopaedic disorders that could interfere with gait.
12
www.medicaljournals.se/jrm
Randomization
An independent person allocated participants to 1 of the 2
intervention groups using stratified block-randomization: (i)
AFO provision at inclusion, in study week 1 (early group);
or (ii) AFO provision 8 weeks later, in study week 9 (delayed
group). Randomization was performed with sealed envelopes
in blocks of 4 with a ratio of 1:1. Stratification was based on the
Functional Ambulation Categories (FAC) (11). Walking with
(FAC 0–2) and without (FAC 3–5) physical support of another
person at inclusion were used as stratification categories before
randomization.
Provision of ankle-foot orthoses
Subjects were provided with 1 of 3 commonly used types of off-
the-shelf, non-articulated, posterior leaf design, polyethylene
or polypropylene AFOs; flexible, semi-rigid or rigid (Basko
Healthcare, Zaandam, the Netherlands). The type of AFO was
chosen in week 1 (early group) or week 9 (delayed group).
AFO-fitting was performed by a licensed orthotist. AFO type
was chosen according to a custom-developed protocol (12).
Besides the AFO-intervention, all subjects received usual care
from experienced physiotherapists according to the Dutch
guidelines for physiotherapy after stroke (13, 14).
Procedures
Measurements were performed 4 times in both groups and
were planned in week 1 (T1), 9 (T2), 17 (T3) and 26 (T4) of
the study. T1 and T2 correspond with the point in time at which
the AFO was provided in both groups. The 8 weeks between
T1 and T2 were also incorporated between T2 and T3, T4
was planned as follow-up measurement after 26 weeks. The
measurements required that subjects were able to walk without
physical support of another person (FAC ≥ 3) and had sufficient
endurance to complete a measurement. If this was not the case,
the measurement was postponed until these requirements were
met. Measurements were performed with and without AFO in
randomized order. Subjects in the delayed group did not use an
AFO at T1 and were therefore measured at T1 without AFO only.
Data collection and processing
At inclusion, basic demographic data were recorded. Actual
AFO use was assessed for every measurement. Measurements
were performed in a gait laboratory. Muscle activation pattern of
the TA muscle was assessed using surface EMG (sEMG), using
a wireless 16-channel Biotel 99 EMG-amplifier (Glonner, Mu-
nich, Germany) with a cut-off frequency of 600 Hz/–3 dB and
a first order 17-Hz high-pass filter. Arbo sg93 electrodes (Covi-
dien, Mansfield, MA, USA) were used and electrode-placement
and skin preparation were according to the SENIAM protocol
(15). Subjects walked on a level walkway over a distance of
8 m at self-selected walking speed, wearing their own shoes.
sEMG electrodes were not removed between measurements
with and without AFO. Assistive devices (such as cane or quad
stick) were allowed and subjects were allowed to rest between
the trials if necessary.
Raw sEMG-signals were digitized at 1,000 Hz sampling rate
with 16-bits resolution and stored on a VICON MX13+ motion-
analysis system (Vicon, Oxford, UK). Simultaneously with