TY - JOUR
T1 - Functional and structural cortical characteristics after restricted focal motor cortical infarction evaluated at chronic stage - Indications from a preliminary study
AU - Julkunen, Petro
AU - Määttä, Sara
AU - Säisänen, Laura
AU - Kallioniemi, Elisa
AU - Könönen, Mervi
AU - Jäkälä, Pekka
AU - Vanninen, Ritva
AU - Vaalto, Selja
PY - 2016/8/1
Y1 - 2016/8/1
N2 - Objective: To assess the inter-hemispheric differences in neuronal function and structure of the motor cortex in a small group of chronic stroke patients having suffered a restricted ischemic lesion affecting hand motor representation. GABAergic intracortical inhibition, known to be affected by stroke lesion, was also investigated. Methods: Eight patients exhibiting little or no motor impairment were studied using transcranial magnetic stimulation (TMS) and diffusion weighted imaging (DWI) >15 months from diagnosis. Resting motor threshold (MT) for 50 μV and 2 mV motor evoked potentials, and short-interval intracortical inhibition (SICI) were measured from hand muscles. Apparent diffusion coefficients (ADCs) were analyzed from the DWI for the primary motor cortex (M1), the supplementary motor area (SMA) and thalamus for reflecting changes in neuronal organization. Results: The MTs did not differ between the affected (AH) and unaffected hemisphere (UH) in 50 μV responses, while the MTs for 2 mV responses were higher (p = 0.018) in AH. SICI was weakened in AH (p = 0.008). ADCs were higher in the affected M1 compared to the unaffected M1 (p = 0.018) while there were no inter-hemispheric differences in SMA or thalamus. Conclusions: Inter-hemispheric asymmetry and neuronal organization demonstrated abnormalities in the M1. However, no confident inference can be made whether the observed alterations in neurophysiological and imaging measures have causal role for motor rehabilitation in these patients. Significance: Neurophysiological changes persist and are detectable using TMS years after stroke even though clinical symptoms have normalized.
AB - Objective: To assess the inter-hemispheric differences in neuronal function and structure of the motor cortex in a small group of chronic stroke patients having suffered a restricted ischemic lesion affecting hand motor representation. GABAergic intracortical inhibition, known to be affected by stroke lesion, was also investigated. Methods: Eight patients exhibiting little or no motor impairment were studied using transcranial magnetic stimulation (TMS) and diffusion weighted imaging (DWI) >15 months from diagnosis. Resting motor threshold (MT) for 50 μV and 2 mV motor evoked potentials, and short-interval intracortical inhibition (SICI) were measured from hand muscles. Apparent diffusion coefficients (ADCs) were analyzed from the DWI for the primary motor cortex (M1), the supplementary motor area (SMA) and thalamus for reflecting changes in neuronal organization. Results: The MTs did not differ between the affected (AH) and unaffected hemisphere (UH) in 50 μV responses, while the MTs for 2 mV responses were higher (p = 0.018) in AH. SICI was weakened in AH (p = 0.008). ADCs were higher in the affected M1 compared to the unaffected M1 (p = 0.018) while there were no inter-hemispheric differences in SMA or thalamus. Conclusions: Inter-hemispheric asymmetry and neuronal organization demonstrated abnormalities in the M1. However, no confident inference can be made whether the observed alterations in neurophysiological and imaging measures have causal role for motor rehabilitation in these patients. Significance: Neurophysiological changes persist and are detectable using TMS years after stroke even though clinical symptoms have normalized.
KW - Diffusion weighted imaging
KW - Infarction
KW - Motor cortex
KW - Motor evoked potential
KW - Navigated transcranial magnetic stimulation
KW - Stroke
UR - http://www.scopus.com/inward/record.url?scp=84974849229&partnerID=8YFLogxK
U2 - 10.1016/j.clinph.2016.05.013
DO - 10.1016/j.clinph.2016.05.013
M3 - Article
AN - SCOPUS:84974849229
VL - 127
SP - 2775
EP - 2784
JO - Clinical Neurophysiology
JF - Clinical Neurophysiology
SN - 1388-2457
IS - 8
ER -