Journal of Rehabilitation Medicine 51-4inkOmslag | Page 74
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A. Chalard et al.
METHODS
Participants
This pilot case-controlled prospective observational study
included 10 adults with brain injury (HEMI) and 10 control
participants (CONTROL) (see Table I for participants’ demo-
graphics). The inclusion criteria were: brain injury for at least 6
months caused by an acquired cerebral lesion (single stroke or
traumatic brain injury); strength of paretic triceps brachii (rated
at least at 3/5 on the Held-Deseilligny Scale, corresponding
to extension of the forearm against slight resistance); and no
anti-spastic treatment during the 3 previous months. Exclusion
criteria were: severe cognitive disorders with limited compre-
hension of basic instructions; neurodegenerative conditions
other than the acquired brain injury; elbow contracture (loss
of passive elbow extension or flexion); and upper limb pain
during movement. Ethics approval was obtained from the local
institutional review board at Paul Sabatier University Hospital
(No. 07-0716, Toulouse, France) and written informed consent
was obtained from all participants. The study was conducted
in accordance with the amended Declaration of Helsinki and
conforms to all STROBE guidelines, reporting the required
information accordingly.
Materials
Net torque around the elbow joint was recorded at 1 kHz using
a Con-Trex MJ calibrated dynamometer (CMV AG, Dubendorf,
Switzerland).
The surface electromyographic signal (EMG) was recorded
at 1 kHz using Ag–AgCl bipolar electrodes in bipolar confi-
guration with an inter-electrode distance of 20 mm,, using an
MP150 system (Biopac Systems Inc., Goleta, CA, USA). The
reference electrode was placed on the left ulnar head. Biceps
brachii and brachioradialis were selected as the elbow flexors
acting as antagonist muscles during elbow extension.
Recordings were made on the non-dominant side in the CON-
TROL group and on the paretic side in HEMI group.
Torque and EMG data were synchronized automatically using
a rectangular triggering pulse signal and analysed offline.
Procedure
The experimental procedure comprised 2 steps.
First step. To perform the following clinical assessment (7):
spasticity of elbow flexors, limitation to active elbow extension,
Fig. 1. Illustration of the arm and forearm positions used to perform
torque and electromyographic recordings during isometric elbow
extension on the calibrated dynamometer.
motor selectivity and motor function were assessed respec-
tively, using the Tardieu scale, a goniometer during repetitive
and dynamic voluntary elbow extensions at a preferred rate,
the upper limb motor section of the Fugl-Meyer Assessment
scale, and the Action Research Arm Test (Table I). Maximal net
elbow extension torque value was taken as a functional marker
of triceps brachii paresis, the Fugl-Meyer score as a motor
selectivity assessment, and the Action Research Arm Test as a
motor function assessment.
Second step. Participants were seated on the dynamometer chair
with their upper body strapped firmly, the upper arm positioned
along the trunk, and the elbow flexed at 90° (Fig. 1). The parti-
cipants exerted 3 isometric maximal voluntary contractions of
the elbow in flexion and in extension for a duration of 5 s, with
1 min rest between each contraction and 3 min rest between
flexion and extension contractions. After collection of maximal
voluntary contraction data, participants performed 2 sets of 5-s
elbow isometric extension sub-maximal contractions while
receiving visual feedback on their actual torque in relation to
a target torque. Each set included 6 contractions at 25% Maxi-
mal Voluntary Contraction (MVC), corresponding to a level of
force required for daily activities (8). The time between each
contraction was 30 s; each set was separated by a 3-min rest
period to minimize fatigue.
Table I. Participants’ demographics
Fugl-Meyer
Disease
Assessment score Action Research
course, month (upper limb/66)
Arm Test (/57)
–
Participants Sex Control Group 6 Males
30 (15)*
4 Females – –
Female
Male
Male
Male
Male
Male
Male
Male
Male
Male Ischaemic stroke
Haemorrhagic stroke
Ischaemic stroke
Ischaemic stroke
Ischaemic stroke
Ischaemic stroke
Ischaemic stroke
Traumatic brain injury
Traumatic brain injury
Haemorrhagic stroke Left, cortical & subcortical
48
Left, thalamic
14
Left, latero-bulbar
27
Left, subcortical
43
Left, cortical & subcortical
39
Right, cortical & subcortical
60
Right, cortical & subcortical 146
Left, cortical & subcortical
132
Right, cortical & subcortical 360
Left, subcortical
60
(n = 10)
Brain Injured Group
1
2
3
4
5
6
7
8
9
10
Age, year Pathology
Side and location of
cerebral injury
47
66
59
52
64
71
33
41
57
63
– –
55
51
59
48
60
44
54
46
18
32 39
36
55
18
57
23
51
29
0
0
*Mean (standard deviation (SD)), indicates a significant difference in age between HEMI and CONTROL groups (p < 0.05).
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