Contribution of corticospinal drive to ankle plantar flexor muscle activation during gait in adults with cerebral palsy
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Contribution of corticospinal drive to ankle plantar flexor muscle activation during gait in adults with cerebral palsy. / Frisk, Rasmus Feld; Lorentzen, Jakob; Nielsen, Jens Bo.
In: Experimental Brain Research, Vol. 237, No. 6, 2019, p. 1457-1467.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Contribution of corticospinal drive to ankle plantar flexor muscle activation during gait in adults with cerebral palsy
AU - Frisk, Rasmus Feld
AU - Lorentzen, Jakob
AU - Nielsen, Jens Bo
PY - 2019
Y1 - 2019
N2 - Impaired plantar flexor muscle activation during push-off in late stance contributes importantly to reduced gait ability in adults with cerebral palsy (CP). Here we used low-intensity transcranial magnetic stimulation (TMS) to suppress soleus EMG activity during push-off as an estimate of corticospinal drive in CP adults and neurologically intact (NI) adults. Ten CP adults (age 34 years, SD 14.6, GMFCS I-II) and ten NI adults (age 33 years, SD 9.8) walked on a treadmill at their preferred walking speed. TMS of the leg motor cortex was elicited just prior to push-off during gait at intensities below threshold for motor-evoked potentials. Soleus EMG from steps with and without TMS were averaged and compared. Control experiments were performed while standing and in NI adults during gait at slow speed. TMS induced a suppression at a latency of about 40 ms. This suppression was similar in the two populations when differences in control EMG and gait speed were taken into account (CP 18%, NI 16%). The threshold of the suppression was higher in CP adults. The findings suggest that corticospinal drive to ankle plantar flexors at push-off is comparable in CP and NI adults. The higher threshold of the suppression in CP adults may reflect downregulation of cortical inhibition to facilitate corticospinal drive. Interventions aiming to facilitate excitability in cortical networks may contribute to maintain or even improve efficient gait in CP adults.
AB - Impaired plantar flexor muscle activation during push-off in late stance contributes importantly to reduced gait ability in adults with cerebral palsy (CP). Here we used low-intensity transcranial magnetic stimulation (TMS) to suppress soleus EMG activity during push-off as an estimate of corticospinal drive in CP adults and neurologically intact (NI) adults. Ten CP adults (age 34 years, SD 14.6, GMFCS I-II) and ten NI adults (age 33 years, SD 9.8) walked on a treadmill at their preferred walking speed. TMS of the leg motor cortex was elicited just prior to push-off during gait at intensities below threshold for motor-evoked potentials. Soleus EMG from steps with and without TMS were averaged and compared. Control experiments were performed while standing and in NI adults during gait at slow speed. TMS induced a suppression at a latency of about 40 ms. This suppression was similar in the two populations when differences in control EMG and gait speed were taken into account (CP 18%, NI 16%). The threshold of the suppression was higher in CP adults. The findings suggest that corticospinal drive to ankle plantar flexors at push-off is comparable in CP and NI adults. The higher threshold of the suppression in CP adults may reflect downregulation of cortical inhibition to facilitate corticospinal drive. Interventions aiming to facilitate excitability in cortical networks may contribute to maintain or even improve efficient gait in CP adults.
U2 - 10.1007/s00221-019-05520-3
DO - 10.1007/s00221-019-05520-3
M3 - Journal article
C2 - 30900000
VL - 237
SP - 1457
EP - 1467
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 6
ER -
ID: 216478149