Article

Evolution of changes in intracortical excitability following stroke,
particularly in the contralesional hemisphere, is being increasingly recognized
in relation to maximizing the potential for functional recovery. OBJECTIVE: The
present study utilized a prospective longitudinal design over a 12-month period
from stroke onset, to investigate the evolution of intracortical excitability
involving both motor cortices and their relationship to recovery, and whether
such changes were influenced by baseline stroke characteristics. METHODS:
Thirty-one patients with acute unilateral ischemic stroke were recruited from a
tertiary hospital stroke unit. Comprehensive clinical assessments and cortical
excitability were undertaken at stroke onset using a novel threshold-tracking
paired-pulse transcranial magnetic stimulation technique, and repeated at 3-, 6-,
and 12-month follow-up in 17 patients who completed the longitudinal assessment.
RESULTS: Shortly following stroke, short-interval intracortical inhibition (SICI)
was significantly reduced in both lesioned and contralesional hemispheres that
correlated with degree of recovery over the subsequent 3 months. Over the
follow-up period, ipsilesional SICI remained reduced in all patient groups, while
SICI over the contralesional hemisphere remained reduced only in the groups with
cortical stroke or more baseline functional impairment. CONCLUSIONS: The current
study has demonstrated that evolution of intracortical excitability, particularly
over the contralesional hemisphere, may vary between patients with differing
baseline stroke and clinical characteristics, suggesting that ongoing
contralesional network recruitment may be necessary for those patients who have
significant disruptions to the integrity of ipsilesional motor pathways. Results
from the present series have implications for the development of neuromodulatory
brain stimulation protocols to harness and thereby facilitate stroke recovery.
CI - (c) The Author(s) 2015.

Langue : ANGLAIS