Stronger proprioceptive BOLD-responses in the somatosensory cortices reflect worse sensorimotor function in adolescents with and without cerebral palsy

https://doi.org/10.1016/j.nicl.2021.102795Get rights and content
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Highlights

  • Cerebral palsy adolescents had stronger proprioceptive BOLD-responses.

  • Cerebral palsy adolescents had worse sensorimotor performance.

  • Stronger BOLD-responses were associated with worse sensorimotor performance.

Abstract

Cerebral palsy (CP) is a motor disorder where the motor defects are partly due to impaired proprioception. We studied cortical proprioceptive responses and sensorimotor performance in adolescents with CP and their typically-developed (TD) peers. Passive joint movements were used to stimulate proprioceptors during functional magnetic resonance imaging (fMRI) session to quantify the proprioceptive responses whose associations to behavioral sensorimotor performance were also examined.

Twenty-three TD (15 females, age: mean ± standard deviation 14.2 ± 2.4 years) and 18 CP (12 females, age: mean ± standard deviation, 13.8 ± 2.3 years; 12 hemiplegic, 6 diplegic) participants were included in this study. Participants’ index fingers and ankles were separately stimulated at 3 Hz and 1 Hz respectively with pneumatic movement actuators. Regions-of-interest were used to quantify BOLD-responses from the primary sensorimotor (SM1) and secondary (SII) somatosensory cortices and were compared across the groups. Associations between responses strengths and sensorimotor performance measures were also examined.

Proprioceptive responses were stronger for the individuals with CP compared to their TD peers in SM1 (p < 0.001) and SII (p < 0.05) cortices contralateral to their more affected index finger. The ankle responses yielded no significant differences between the groups. The CP group had worse sensorimotor performance for hands and feet (p < 0.001). Stronger responses to finger stimulation in the dominant SM1 (p < 0.001) and both dominant and non-dominant SII (p < 0.01, p < 0.001) cortices were associated with the worse hand sensorimotor performance across all participants.

Worse hand function was associated with stronger cortical activation to the proprioceptive stimulation. This association was evident both in adolescents with CP and their typically-developed controls, thus it likely reflects both clinical factors and normal variation in the sensorimotor function. The specific mechanisms need to be clarified in future studies.

Abbreviations

fMRI
functional magnetic resonance imaging
CP
cerebral palsy
HP
hemiplegic
DP
diplegic
BOLD
Blood-Oxygen-Level-Dependent signal
ROI
regions of interest
SI cortex
primary somatosensory cortex
SII cortex
secondary somatosensory cortex
TD
typically-developed
GMFCS
Gross Motor Function Classification System
TR
repetition time
TE
echo time
EPI
echo planar imaging
SIPT
Sensory Integration and Praxis Tests
GLM
General Linear Model
SPM
Statistical Parametric Mapping
EM
expectation maximization
MANCOVA
Multivariate analysis of covariance
PSC
percent signal change

Keywords

Passive movement
SM1
SII
Kinesthesia
Hemiplegia
Diplegia

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