Motor plasticity after extra-intracranial bypass surgery in occlusive cerebrovascular disease.
OBJECTIVE
To explore plasticity in patients scheduled for extra-intracranial bypass surgery due to unilateral symptomatic occlusive cerebrovascular disease via navigated transcranial magnetic stimulation.


METHODS
In this observational study, patients were allocated to different substudies and examined before and 3 months after operation. (1) Corticospinal excitability was determined via identification of the resting motor threshold. (2) Intracortical inhibition and facilitation were tested by paired pulse transcranial magnetic stimulation. (3) Area of cortical representation of the first dorsal interosseous muscle was identified.


RESULTS
(1) Resting motor thresholds were higher in the affected hemispheres with impaired cerebrovascular reserve capacity compared to the unaffected hemispheres (45.7% ± 2.2% compared to 39.2% ± 1.4%, n = 39, p < 0.05). Reduced excitability normalized 3 months after revascularization (51% ± 2.6% → 45% ± 1.9%, n = 21, p < 0.05). (2) In paired pulse paradigms, there was a motor disinhibition in the operated hemispheres. (3) There was a reduction of the cortical representation areas of the first dorsal interosseous muscle (2.3 ± 0.5 cm(2) → 0.9 ± 0.6 cm(2), n = 9, p < 0.05) after operation.


CONCLUSIONS
Our data demonstrate a reversibly impaired motor cortical function in the chronically ischemic brain. In carefully selected patients, cerebral revascularization leads to improved motor output indicated by a lower resting motor threshold, intracortical disinhibition, and more focused motor cortical representation.
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Daniel
D
Jussen
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Anna
A
Zdunczyk
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Sein
S
Schmidt
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Judith
J
Rösler
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Ralph
R
Buchert
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Petro
P
Julkunen
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Jari
J
Karhu
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Stephan
S
Brandt
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland.
Thomas
T
Picht
From the Departments of Neurosurgery (D.J., A.Z., J.R., T.P., P.V.), Neurology (S.S., S.B.), and Nuclear Medicine (R.B.), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (D.J.), Dr. Horst-Schmidt-Kliniken, Wiesbaden, Germany; Department of Clinical Neurophysiology (P.J., J.K.), Kuopio University Hospital; and Nexstim Ltd. (J.K.), Helsinki, Finland. peter.vajkoczy@charite.de.
Peter
P
Vajkoczy
D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002548:Cerebral Revascularization; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000276:immunology* / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D011712:Pyramidal Tracts / Q000000981:diagnostic imaging / Q000503:physiopathology; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome