Corticospinal Excitability in Children with Congenital Hemiparesis

Abstract

Transcranial magnetic stimulation (TMS) can be used as an assessment or intervention to evaluate or influence brain activity in children with hemiparetic cerebral palsy (CP) commonly caused by perinatal stroke. This communication report analyzed data from two clinical trials using TMS to assess corticospinal excitability in children and young adults with hemiparetic CP. The results of this communication revealed a higher probability of finding a motor evoked potential (MEP) on the non-lesioned hemisphere compared to the lesioned hemisphere (p = 0.005). The resting motor threshold (RMT) was lower on the non-lesioned hemisphere than the lesioned hemisphere (p = 0.013). There was a significantly negative correlation between age and RMT (rs = −0.65, p = 0.003). This communication provides information regarding MEP responses, motor thresholds (MTs) and the association with age during TMS assessment in children with hemiparetic CP. Such findings contribute to the development of future pediatric studies in neuroplasticity and neuromodulation to influence motor function and recovery after perinatal stroke.

Transcranial magnetic stimulation as a diagnostic and therapeutic tool in cerebral palsy

“…SICI is decreased and ICF unaltered in CP [81]. The interhemispheric inhibition is altered or absent and MT is higher on the lesioned side [82][83][84].…”

Influence of Combined Transcranial Direct Current Stimulation and Motor Training on Corticospinal Excitability in Children With Unilateral Cerebral Palsy

“…Children with unilateral cerebral palsy (UCP), who experience a stroke or brain injury around the time of birth, demonstrate atypical patterns of corticospinal tract (CST) development and organization (Berweck et al, 2008; Staudt, 2010). which contributes to an imbalance in excitability between the lesioned and non-lesioned hemispheres (Berweck et al, 2008; Chen et al, 2016). These neural changes underlie the limitations in upper-extremity function (Holmström et al, 2010) that impact independence throughout their lifetime.…”

“…CSP is the duration of inhibition during voluntary muscle contraction with contributions from both spinal and supraspinal inhibitory inputs, and may reflect GABA B activity in these areas (Cantello et al, 1992; McDonnell et al, 2006). Prior studies have examined these measures of corticospinal excitability, both before and after interventions to begin to identify neurophysiology mechanisms in children with UCP (Chen et al, 2016; Zewdie et al, 2017; Kuo et al, 2018; Rich et al, 2018). Specifically, Kuo et al (2018) describe intervention-induced changes in contralesional corticospinal excitability following intensive therapy and repetitive TMS, and their relationship to motor function outcomes.…”

Heart rate and blood pressure responses to corticomotor stimulation in young, healthy adults

“…Single-pulse transcranial magnetic stimulation (sp-TMS) is used to measure cortical excitability ( Chen et al, 2016 ). Serious adverse events of syncope have occurred with sp-TMS ( Gillick et al, 2015 , Keller-Ross et al, 2018 ) .…”

“…A 70 mm figure-of-eight TMS coil connected to a Magstim 200 2 stimulator (Magstim, Whitland, UK) delivered sp-TMS to the primary motor cortex (M1) guided by a neural navigation system (Brainsight, Montreal, QC, Canada). RMT was identified when sp-TMS elicited motor evoked potentials (MEPs) of ≥50 μV peak-to-peak from the first dorsal interosseous of the dominant hand, identified via the Edinburgh handedness inventory, in ≥3 of 5 stimulations ( Chen et al, 2016 ).…”