Format

Send to

Choose Destination
Clin Neurophysiol. 2008 Mar;119(3):683-692. doi: 10.1016/j.clinph.2007.11.004. Epub 2007 Dec 27.

Abnormal corticomotor excitability assessed in biceps brachii preceding pronator contraction post-stroke.

Author information

1
Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Suite 1406, 345 E Superior Street, Chicago, IL 60611, USA.
2
Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Suite 1406, 345 E Superior Street, Chicago, IL 60611, USA. Electronic address: j-stinear@northwestern.edu.

Abstract

OBJECTIVE:

To assess corticomotor (CM) excitability of the antagonist biceps brachii (BB) post-stroke in preparation for pronator contraction. In healthy subjects, we previously demonstrated that prior to pronator contraction CM excitability of the antagonist BB was suppressed.

METHODS:

Transcranial magnetic stimulation (TMS) was used to assess pre-contraction changes in motor evoked potential (MEP) amplitude of the BB, when BB was acting either as an antagonist or an agonist. TMS was applied 100-200ms prior to rhythmic isometric BB or pronator contractions in chronic stroke survivors and age/gender matched healthy control subjects.

RESULTS:

Prior to pronator contraction, MEPs in BB were elicited in the stroke group but were absent in healthy controls indicating that CM excitability of the antagonist BB was increased post-stroke. The extent of the abnormal increase in excitability positively correlated with the extent of upper limb motor impairment.

CONCLUSIONS:

Our results suggest that an alteration of cortical control mechanisms regulating motor excitability of the antagonist BB may contribute to the impairment of upper limb motor coordination post-stroke.

SIGNIFICANCE:

This study offers a unique approach to study the potential for a cortical origin of post-stroke motor discoordination.

PMID:
18164237
PMCID:
PMC2288665
DOI:
10.1016/j.clinph.2007.11.004
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center