Bilateral alterations in somatosensory cortical processing in hemiplegic cerebral palsy

Abstract

MACS Manual Ability ClassificationMETHOD We recorded somatosensory evoked magnetic fields in response to hand area stimulation from eight adolescents with hemiplegic CP (five females and three males; mean age 14y 6mo, SD 2y 3mo) and eight age-and sex-matched healthy comparison adolescents (mean age 15y 4mo, SD 2y 4mo). All participants in the CP group had purely subcortical brain lesions in magnetic resonance images. RESULTSThe somatosensory representation of the affected limb was contralateral (i.e. ipsilesional), but detailed inspection of the evoked responses showed alterations bilaterally. In the primary somatosensory cortex, the representation areas of digits II and V were in both hemispheres closer to each other in participants with CP than in comparison participants [ANOVA main effect group F 1,14 =5.58; p=0.03]. In addition, the morphology of median nerve evoked fields was altered in the participants with CP.

Cortical Somatosensory Reorganization in Children with Spastic Cerebral Palsy: A Multimodal Neuroimaging Study

“…Functional alterations in the magnetic evoked responses observed here have also been previously reported after the tactile stimulation of fingers and after the electrical stimulation of the median nerve in HCP children with subcortical lesions (Nevalainen et al, 2012). These alterations include missing deflections, aberrant morphology, and different distances in the localized SEFs components between CP and TD patients.…”

“…Aside from motor and postural impairments, children with SCP frequently experience sensory deficits such as altered tactile, proprioceptive, kinesthetic, and pain awareness (Van Heest et al, 1993; Cooper et al, 1995; Krumlinde-Sundholm and Eliasson, 2002; Sanger and Kukke, 2007; Wingert et al, 2009; Riquelme et al, 2011). Recent functional neuroimaging studies have reported altered SS processing in SCP individuals as measured by SS-evoked potentials or fields in terms of amplitude, morphology, frequency power, or somatotopy (Riquelme and Montoya, 2010; Kurz and Wilson, 2011; Teflioudi et al, 2011; Guo et al, 2012; Nevalainen et al, 2012; Pihko et al, 2014; Riquelme et al, 2014). In a recent magnetoencephalography (MEG) study, Pihko et al (2014) found that suppression and rebound of alpha and beta cortical activity to contralateral stimulation were smaller in the lesioned compared to the intact hemisphere in hemiplegic CP (HCP) children, while they did not find any difference between the hemispheres of typically developing (TD) children.…”

“…MEG was used because it is able to elucidate the dynamic spatiotemporal characteristics of SS cortical activation (Lin et al, 2006a) with its excellent temporal and good spatial accuracy (Hämäläinen et al, 1993; Papadelis et al, 2009). So far, there are very few MEG studies reporting functional abnormalities in the SS cortex of CP children (Kurz and Wilson, 2011; Nevalainen et al, 2012; Pihko et al, 2014). With MEG, we tested our hypotheses that the SEFs will be abnormal and the primary cortical SS representation areas will present an altered somatotopy in the affected (or more affected) compared to the intact (or less affected) hemisphere of CP children, and compared to both hemispheres of TD children.…”

Advances and limitations in our knowledge of cortical reorganization in cerebral palsy

“…1,2 Aside from atypical hemispheric dominance of motor control, other evidence demonstrates atypical interactions between hemispheres through transcallosal fibers. 2 Additional studies, such as the Nevalainen et al MEG study, 5 have examined cortical somatosensory reorganization in children with cerebral palsy. Such studies suggest that somatosensory representation of the affected limb can be represented bilaterally, by both the affected and unaffected hemispheres, 5 although other patterns of somatosensory reorganization have been reported.…”

“…The latest PNME is perhaps the shaking body attack 5 and doubtless more will be described and reduce the number of unclassified PNMEs, and so satisfy the 'splitters'. By contrast, 'lumpers' might wish to add in infantile masturbation to create an all-encompassing benign non-epileptic episodic contractions in infancy (Nechay A, King MD, Stephenson JBP, personal communication 2009).…”