Journal of Rehabilitation Medicine 51-4inkOmslag | Page 73
J Rehabil Med 2019; 51: 307–311
SHORT COMMUNICATION
SPASTIC CO-CONTRACTION, RATHER THAN SPASTICITY, IS ASSOCIATED WITH
IMPAIRED ACTIVE FUNCTION IN ADULTS WITH ACQUIRED BRAIN INJURY: A
PILOT STUDY
Alexandre CHALARD, PT, MS 1,2 , David AMARANTINI, PhD 1 , Joseph TISSEYRE, MS 1 , Philippe MARQUE, MD, PhD 1,3 ,
Jessica TALLET, PhD 1 and David GASQ, MD, PhD 1,4
From the 1 ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, 2 Ipsen Innovation, Les Ulis, 3 Department of
Physical Medicine and Rehabilitation and 4 Department of Functional Physiological Explorations, University Hospital of Toulouse, Hôpital
de Rangueil, Toulouse, France
Objective: To elucidate the adverse consequences of
spasticity and spastic co-contraction of elbow flex-
ors on motor impairment and upper limb functional
limitation.
Design: A pilot case-controlled prospective observa-
tional study.
Subjects: Ten brain-injured adults, and 10 healthy
controls.
Methods: The co-contraction index was computed
from electromyographic recordings of elbow flexors
during sub-maximal (25% Maximal Voluntary Cont-
raction) isometric elbow extension. Spasticity was
assessed with the Tardieu scale, upper limb limita-
tion using a goniometer during active elbow exten-
sion, motor selectivity with the Fugl-Meyer Assess-
ment for the upper limb, and motor function with
the Action Research Arm Test.
Results: Greater co-contraction occurred in patients
with brain injury compared with controls. In cont-
rast to spasticity, strong associations were found
between the co-contraction index, the limitation of
active elbow extension, the Fugl-Meyer Assessment,
and the Action Research Arm Test.
Conclusion: This pilot study suggests that spastic
co-contraction rather than spasticity is an important
factor in altered upper limb motricity in subjects
with brain injury, leading to abnormal restricting
arm movement patterns in subjects with more seve-
re motor impairment. Practical applications directly
concern the pre- and post-therapeutic evaluation of
treatments aimed at improving motor skills in sub-
jects with brain injury.
Key words: brain injury; hemiplegia; muscle hypertonia; up-
per extremity.
Accepted Jan 29, 2019; Epub ahead of print Feb 15, 2019
J Rehabil Med 2019; 51: 307–311
Correspondence address: David Gasq, Toulouse NeuroImaging Cen-
ter, CHU Purpan, Pavillon Baudot, place du Dr Baylac 31024 Toulouse,
France. E-mail: [email protected]
M
uscle overactivity, including spasticity and spas-
tic co-contraction in particular, describes invo-
luntary motor unit recruitment, which occurs in spastic
LAY ABSTRACT
Spasticity and spastic co-contraction are expressions of
muscle overactivity that occur in spastic paresis syn-
drome after a brain injury. The objective of the pre-
sent pilot study was to improve our understanding of
the respective adverse consequences of spasticity and
spastic co-contraction on motor disability. In contrary
to spasticity, spastic co-contraction is strongly associa-
ted with motor impairment in subjects with brain injury.
Therapies should be directed toward reducing spastic
co-contraction in order to improve motor function.
paresis syndrome after a brain injury, such as stroke or
traumatic brain injury (1). Spasticity is defined as an
increase in velocity-dependent stretch reflexes, and is
clinically manifested by excessive responses to mus-
cle stretch (2). Spasticity is used as a convenient way
to assess muscle overactivity during passive and fast
muscular stretch. Spastic co-contraction, as assessed
by electromyography using the muscle co-contraction
index (3), refers to increased antagonist muscle recru-
itment triggered by the volitional command of agonist
muscles in the absence of a phasic stretch (1). It has
been well established that spasticity and spastic co-
contraction have different underlying physiological
mechanisms (1), but their consequences on motor
function remain to be confirmed and elucidated. It has
been suggested that spastic co-contraction may contri-
bute to limitations in active movement (4). However,
to date, the impact of this disabling form of muscle
overactivity on motor function in brain-injured adults
has been only sparsely and indirectly studied (5). In
addition, most treatments aimed at improving upper
limb function, such as rehabilitation or botulinum
toxin, focus on spasticity as the primary outcome in
clinical practice (6).
The aim of the present pilot study was therefore to
elucidate the adverse consequences of spasticity and
spastic co-contraction of elbow flexors on upper limb
motor impairment and disability. The results of this
study may have direct application in improving the
evaluation and implementation of treatments aimed at
improving motor function in subjects with brain injury.
This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm
Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977
doi: 10.2340/16501977-2528