Excitatory and inhibitory corticospinal responses to transcranial magnetic stimulation in patients with minor to moderate head injury
A V Chistyakov, J F Soustiel, H Hafner, M Trubnik, G Levy, M Feinsod
The
Center for Treatment and Applied Research in Head Injury, Department of
Neurosurgery Rambam (Maimonides) Medical Center, PO Box 9602, Haifa
31096, Israel ; B Rappaport Faculty of Medicine, The Technion, Israel
Institute of Technology, Haifa, Israel
Correspondence to: Dr A V Chistyakov a_chistyakov{at}rambam.health.gov.il
Received 8 May 2000 and in revised form 1 November 2000;
Accepted 15 November
2000
OBJECTIVES
The changes
in excitatory and inhibitory responses to transcranial magnetic
stimulation (TMS), as attested by motor evoked potential (MEP) and
silent period (SP) parameters, were compared in patients who sustained
minor to moderate head injury.
METHODSA total of 38 patients with brain concussion, and diffuse, focal, and combined brain
injury and 20 healthy volunteers were examined. The MEPs and SPs were
recorded from the abductor pollicis brevis muscle after single pulse
TMS 2 weeks after head trauma. The parameters assessed were the MEP
resting threshold, the MEP/M wave amplitude ratio, the central motor
conduction time (CMCT), the SP threshold, the interthreshold difference
(ITD), and the SP duration (SPD).
RESULTSThe main
finding was an increase in the ITD in patients with mild and moderate
head injury due to the relatively greater augmentation of the MEP
threshold. This was associated with a reduction of the MEP/M wave
amplitude ratio. The degree of MEP and SP changes depended on severity
of head injury and was not related to the type of brain lesions. The
SPD did not differ significantly in brain concussion, or diffuse, focal
and combined brain injury groups compared with the control group. The
CMCT was prolonged in patients with diffuse and combined brain lesions.
Among subjective complaints only fatigue was significantly related to
ITD, MEP, and SP threshold abnormalities.
CONCLUSIONSThe
results suggest that mechanisms involved in MEP and SP generation are
differently affected in head injury, the first being impaired more
severely. The increase of the ITD accompanied by reduction of the MEP/M
wave amplitude ratio may reflect a dissociated impairment of inhibitory
and excitatory components of central motor control in head trauma.
Keywords: head injury; silent period; motor evoked potential; transcranial magnetic stimulation
© 2001 by Journal of Neurology, Neurosurgery, and Psychiatry
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
-
De Beaumont, L., Theoret, H., Mongeon, D., Messier, J., Leclerc, S., Tremblay, S., Ellemberg, D., Lassonde, M.
(2009). Brain function decline in healthy retired athletes who sustained their last sports concussion in early adulthood. Brain
132: 695-708
[Abstract] [Full Text]
- Full Text
- Full Text (PDF)
- Submit a response
- Alert me when this article is cited
- Alert me when eLetters are posted
- Alert me if a correction is posted
- Citation Map
Services
- Email this link to a friend
- Similar articles in this journal
- Similar articles in PubMed
- Add article to my folders
- Download to citation manager
- Request Permissions
Citing Articles
Google Scholar
PubMed
Topic Collections
Bookmark with
Register for free content
The full back archive is now available for all BMJ Journals. Institutional subscribers may access the entire archive as part of their subscription. Personal subscribers will also have access to all content when logged in. Non-subscribers who register have free access to all articles published before 2006 right back to volume 1 issue 1. Register here to access the free archive of all BMJ Journals.
Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.
