The Cerebellum

, Volume 12, Issue 6, pp 826–834

Motor Cortex Excitability in Acute Cerebellar Infarct

Authors

    • Neuroscience Research Australia and Prince of Wales Clinical SchoolUniversity of New South Wales
  • Arun V. Krishnan
    • School of Medical SciencesUniversity of New South Wales
  • Steve Vucic
    • Neuroscience Research Australia and Prince of Wales Clinical SchoolUniversity of New South Wales
  • Cindy S-Y. Lin
    • School of Medical SciencesUniversity of New South Wales
    • Neuroscience Research Australia and Prince of Wales Clinical SchoolUniversity of New South Wales
    • University of New South Wales and Neuroscience Research Australia
Original Paper

DOI: 10.1007/s12311-013-0493-8

Cite this article as:
Huynh, W., Krishnan, A.V., Vucic, S. et al. Cerebellum (2013) 12: 826. doi:10.1007/s12311-013-0493-8

Abstract

Limited evidence to date has demonstrated changes in excitability that develops over the contralateral motor cortex after a cerebellar infarct. As such, the present study investigated changes in excitability over the contra- (contraM1) and ipsilateral motor cortices (ipsiM1), in patients with acute cerebellar infarct, to determine whether the changes may have functional relevance. Paired-pulse transcranial magnetic stimulation, combined with detailed clinical assessment, was undertaken in ten patients presenting with acute unilateral cerebellar infarct. Studies were undertaken within 1 week of ictus and followed longitudinally at 3-, 6-, and 12-month periods. Comparisons were made with 15 age-matched controls. Immediately following a stroke, short-interval intracortical inhibition (SICI) was significantly reduced over the contraM1 in all patients (P = 0.01), while reduced over the ipsiM1 in those with severe functional impairment (P = 0.01). Moreover, ipsiM1 SICI correlated with impairment (r = 0.69, P = 0.03), such that less SICI was observed in those patients with most impairment. Cortical excitability changes persisted over the follow-up period in the context of clinical improvement. Following an acute cerebellar infarct, excitability abnormalities develop over both motor cortices, more prominently in patients with severe functional impairment. The cortical changes, particularly over the ipsilateral motor cortex, may represent a functionally relevant plastic process that may guide future therapeutic strategies to better facilitate recovery.

Keywords

StrokeCerebellumPlasticityTranscranial magnetic stimulationCortical inhibition

Abbreviations

BI

Barthel Index

Contra-M1

Contralateral primary motor cortex

DCN

Deep cerebellar nuclei

FM

Fugl–Meyer score

ICF

Intracortical facilitation

Ipsi-M1

Ipsilateral primary motor cortex

M1

Primary motor cortex

MEP

Motor evoked potential

mRS

Modified Rankin scale

NIBS

Non-invasive brain stimulation

NIHSS

National Institutes of Health Stroke Scale

PICA

Posterior inferior cerebellar artery

RMT

Resting motor threshold

SARA

Scale for the assessment and rating of ataxia

SCA

Superior cerebellar artery

SICI

Short-interval intracortical inhibition

tDCS

Transcranial direct current stimulation

TMS

Transcranial magnetic stimulation

Copyright information

© Springer Science+Business Media New York 2013