Av. Chistyakov et al., Dissociation of somatosensory and motor evoked potentials in non-comatose patients after head injury, CLIN NEU, 110(6), 1999, pp. 1080-1089
Objectives: This study was performed to evaluate the clinical value of comb
ined use of somatosensory evoked potentials (SEPs) and motor evoked potenti
als (MEPs) in patients with different brain lesions after head trauma.
Methods: A total of 64 patients with minor and moderate head injury were in
vestigated by means of SEPs recorded over the parietal and frontal areas an
d MEPs following single-pulse transcranial magnetic stimulation (sTMS) and
slow-rate repetitive transcranial magnetic stimulation (rTMS).
Results: in almost 50% of the patients, a dissociated impairment of somatos
ensory and motor evoked potentials was found. This dissociation was related
to different distribution of SEP and MEP abnormalities in head injury subg
roups. The higher threshold to sTMS and increased variability of the MEP am
plitude during slow-rate rTMS were the most prominent features in patients
with focal brain contusions, suggesting impairment of the cortical excitabi
lity. SEP abnormalities, as well as central conduction impairments, were mo
re noticeable in patients with diffuse brain injury.
Conclusions: A combined analysis of SEPs and MEPs may improve the assessmen
t of cortical dysfunctions and central conduction abnormalities in non-coma
tose patients with head injury. A slow-rate rTMS may be considered as a com
plementary technique to the evaluation of the threshold in assessment of th
e excitability of the motor cortex in minor and moderate head injury. (C) 1
999 Elsevier Science Ireland Ltd. All rights reserved.