Impaired movement-related potentials in acute frontal traumatic brain injury.
OBJECTIVE
Focal brain lesions due to traumatic brain injury (TBI) do not only lead to functional deficits in the lesion area, but also disturb the structurally intact neuronal network connected to the lesion site. Therefore we hypothesized dysfunctions of the cortical motor network after frontal TBI. The movement related potential (MRP) is an EEG component related to voluntary movement consisting of the Bereitschaftspotential (BP), the negative slope (NS), and the motor potential (MP). The aim of our study was to demonstrate alterations in the movement related cortical network in the acute stage after TBI by comparing our patients' MRPs to those of a healthy control group.


METHODS
EEGs of 22 patients with magnetic resonance imaging defined contusions of the prefrontal cortex were recorded within 8 weeks after TBI. We further recruited a healthy control group. The paradigm consisted of self-paced abductions of the right index finger.


RESULTS
Compared to healthy controls, the BP in the patient group was significantly reduced and its onset delayed. Moreover, an enhanced contribution of the postrolandic hemisphere ipsilateral to the movement and a reduced contribution of the left frontal cortex, ipsilateral to the lesion in the majority of the patients, were observed during motor execution (MP).


CONCLUSIONS
Anatomical connections between the prefrontal cortex and the supplementary motor area (SMA) are known to exist. We suggest that prefrontal lesions lead to reduced neuronal input into the SMA. This deficit in the preparatory motor network may cause the reduced BPs in our patients. Moreover, an increased need for attentional resources might explain the enhanced motor potentials during movement execution. In conclusion, we demonstrated altered MRPs in the acute stage after frontal TBI, which are a consequence of disturbed neuronal networks involved in the preparation and execution of voluntary movements.
Wiese
Holger
H
Department of Neurology, University of Essen, Hufelandstrasse 55, 45122 Essen, Germany. holger.wiese@uni-essen.de
Stude
Philipp
P
Nebel
Katharina
K
Osenberg
Dorothea
D
Völzke
Volker
V
Ischebeck
Werner
W
Stolke
Dietmar
D
Diener
Hans Christoph
HC
Keidel
Matthias
M
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention; D001930:Brain Injuries / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D003265:Contingent Negative Variation / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance