TY - JOUR
T1 - Evidence for normative intracortical inhibitory recruitment properties in cervical dystonia
AU - Summers, Rebekah L.S.
AU - Chen, Mo
AU - MacKinnon, Colum D.
AU - Kimberley, Teresa J.
N1 - Publisher Copyright:
© 2020 International Federation of Clinical Neurophysiology
PY - 2020/6
Y1 - 2020/6
N2 - Objective: Dystonia is associated with reduced intracortical inhibition as measured by the cortical silent period (cSP); however, this may be due to abnormal cSP threshold or input-output properties. This study evaluated cSP recruitment properties in people with cervical dystonia (CD). Methods: Bilateral electromyographic recordings were collected in the upper trapezius muscle in response to transcranial magnetic stimulation of the left and right primary motor cortex in a group with CD (n = 19) and controls (n = 21). cSP threshold, cSP input-output properties at stimulation intensities from 1 to 1.4x the cSP threshold, ipsilateral silent period duration (iSP) and timing and magnitude of the contralateral and ipsilateral motor evoked potential (MEP) were assessed. Results: The cSP threshold, input-output properties, and contralateral MEP magnitude were not significantly different between groups (all p > 0.07). Hemispheric symmetry was present in the control group while the CD group had reduced iSP (p < 0.01) and a trend for reduced ipsilateral MEP response (p = 0.053) in the left hemisphere. Conclusions: Recruitment properties of intracortical inhibition are similar between control and CD groups. Transcallosal inhibition is asymmetric between hemispheres in people with CD. Significance: Evidence of normative intracortical inhibition recruitment properties challenge the commonly held view that cortical inhibition is reduced in dystonia.
AB - Objective: Dystonia is associated with reduced intracortical inhibition as measured by the cortical silent period (cSP); however, this may be due to abnormal cSP threshold or input-output properties. This study evaluated cSP recruitment properties in people with cervical dystonia (CD). Methods: Bilateral electromyographic recordings were collected in the upper trapezius muscle in response to transcranial magnetic stimulation of the left and right primary motor cortex in a group with CD (n = 19) and controls (n = 21). cSP threshold, cSP input-output properties at stimulation intensities from 1 to 1.4x the cSP threshold, ipsilateral silent period duration (iSP) and timing and magnitude of the contralateral and ipsilateral motor evoked potential (MEP) were assessed. Results: The cSP threshold, input-output properties, and contralateral MEP magnitude were not significantly different between groups (all p > 0.07). Hemispheric symmetry was present in the control group while the CD group had reduced iSP (p < 0.01) and a trend for reduced ipsilateral MEP response (p = 0.053) in the left hemisphere. Conclusions: Recruitment properties of intracortical inhibition are similar between control and CD groups. Transcallosal inhibition is asymmetric between hemispheres in people with CD. Significance: Evidence of normative intracortical inhibition recruitment properties challenge the commonly held view that cortical inhibition is reduced in dystonia.
KW - Cortical excitability
KW - Cortical silent period
KW - Dystonia
KW - Motor evoked potential
KW - Transcallosal inhibition
KW - Transcranial magnetic stimulation
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U2 - 10.1016/j.clinph.2020.03.019
DO - 10.1016/j.clinph.2020.03.019
M3 - Article
C2 - 32304844
AN - SCOPUS:85083180186
SN - 1388-2457
VL - 131
SP - 1272
EP - 1279
JO - Clinical Neurophysiology
JF - Clinical Neurophysiology
IS - 6
ER -