Article

Previous studies have reported that patients with Parkinson's disease (PD) show,
in the "off medication" state, a reduced activation of tibialis anterior (TA) in
the late swing-early stance phase of the gait cycle. In PD patients the
pathophysiological picture may cause differences among the stride cycles. Our
aims were to evaluate how frequently TA activity is reduced in the late
swing-early stance phase and if there is a relationship between the TA pattern
and the clinical picture. Thirty PD patients were studied 2 h after Levodopa
administration ("on-med") and 12 h after Levodopa wash-out ("off-med"). They were
evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS III) and surface
electromyography of TA and gastrocnemius medialis (GM). The root mean square
(RMS) of the TA activity in late swing-early stance phase (RMS-A) was normalized
as a percent of the RMS of the TA activity in late stance-early swing (RMS-B).
RMS-A was reduced in 30% of patients in the "off-med" condition. Within these
patients, the percentage of stride cycles with reduced RMS-A, ranged between 28%
and 83%. After Levodopa intake, no stride cycle showed reduced RMS-A. Patients
with reduced RMS-A had a lower UPDRS III total score in the "on-med" rather than
in the "off-med" condition (p=0.02). Our data confirm and extend previous
observations indicating that, in "off-med" the function of TA is impaired in
those patients clinically more responsive to Levodopa.
TA activation is reduced
in a relatively high percent of gait cycles in the "off-med" state. Since the variability of TA activation disappears after Levodopa administration, this
phenomenon could be the expression of an abnormal dopaminergic drive.
CI - Copyright (c) 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS