TY - JOUR
T1 - Abnormal corticospinal excitability in traumatic diffuse axonal brain injury
AU - Bernabeu, Montse
AU - Demirtas-Tatlidede, Asli
AU - Opisso, Eloy
AU - Lopez, Raquel
AU - Tormos, Jose M.
AU - Pascual-Leone, Alvaro
PY - 2009/12/1
Y1 - 2009/12/1
N2 - This study aimed to investigate the cortical motor excitability characteristics in diffuse axonal injury (DAI) due to severe traumatic brain injury (TBI). A variety of excitatory and inhibitory transcranial magnetic stimulation (TMS) paradigms were applied to primary motor cortices of 17 patients and 11 healthy controls. The parameters of testing included resting motor threshold (MT), motor evoked potential (MEP) area under the curve, input-output curves, MEP variability, and silent period (SP) duration. The patient group overall revealed a higher MT, smaller MEP areas, and narrower recruitment curves compared to normal controls (p<0.05). The alterations in excitability were more pronounced with an increase in DAI severity (p<0.005) and the presence of motor impairment (p<0.05), while co-existence of focal lesions did not affect the degree of MEP changes. MEP variability was significantly lower in the group with motor impairment only (p<0.05). The intracortical inhibition, as revealed by SP duration, did not exhibit any significant differences in any of the patient groups. In conclusion, our findings expand the concept that impairment of the excitatory and inhibitory phenomena in the motor cortex does not proceed in parallel and demonstrate distinct patterns of aberrations in TBI. Furthermore, these data suggest that alterations in the corticospinal excitatory mechanisms are determined predominantly by the severity of DAI, and show a significant relationship with clinical motor dysfunction following severe trauma diffusely affecting the motor cortical connections. In severe TBI, motor and functional recovery might be linked to restitution of normal corticospinal mechanisms, indexed by normalization of the cortical excitability parameters.
AB - This study aimed to investigate the cortical motor excitability characteristics in diffuse axonal injury (DAI) due to severe traumatic brain injury (TBI). A variety of excitatory and inhibitory transcranial magnetic stimulation (TMS) paradigms were applied to primary motor cortices of 17 patients and 11 healthy controls. The parameters of testing included resting motor threshold (MT), motor evoked potential (MEP) area under the curve, input-output curves, MEP variability, and silent period (SP) duration. The patient group overall revealed a higher MT, smaller MEP areas, and narrower recruitment curves compared to normal controls (p<0.05). The alterations in excitability were more pronounced with an increase in DAI severity (p<0.005) and the presence of motor impairment (p<0.05), while co-existence of focal lesions did not affect the degree of MEP changes. MEP variability was significantly lower in the group with motor impairment only (p<0.05). The intracortical inhibition, as revealed by SP duration, did not exhibit any significant differences in any of the patient groups. In conclusion, our findings expand the concept that impairment of the excitatory and inhibitory phenomena in the motor cortex does not proceed in parallel and demonstrate distinct patterns of aberrations in TBI. Furthermore, these data suggest that alterations in the corticospinal excitatory mechanisms are determined predominantly by the severity of DAI, and show a significant relationship with clinical motor dysfunction following severe trauma diffusely affecting the motor cortical connections. In severe TBI, motor and functional recovery might be linked to restitution of normal corticospinal mechanisms, indexed by normalization of the cortical excitability parameters.
KW - Corticospinal excitability
KW - Diffuse axonal injury
KW - Transcranial magnetic stimulation
KW - Traumatic brain injury
UR - http://www.scopus.com/inward/record.url?scp=75449104179&partnerID=8YFLogxK
U2 - 10.1089/neu.2008.0859
DO - 10.1089/neu.2008.0859
M3 - Article
C2 - 19604100
AN - SCOPUS:75449104179
SN - 0897-7151
VL - 26
SP - 2185
EP - 2193
JO - Journal of Neurotrauma
JF - Journal of Neurotrauma
IS - 12
ER -