Bilateral alterations in somatosensory cortical processing in hemiplegic cerebral palsy.
OBJECTIVE
In individuals with cerebral palsy (CP), cerebral insults during early development may induce profound reorganization of the motor representation. This study determined the extent of alterations in cortical somatosensory functions in adolescents with hemiplegic CP with subcortical brain lesions.


METHODS
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.


RESULTS
The 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.


CONCLUSIONS
In hemiplegic CP, modification of the somatosensory cortical network extends beyond what would be expected based on the unilateral symptoms and the anatomical lesion. Further understanding of the functional alterations in the sensorimotor networks may aid in developing more precisely designed rehabilitation strategies.
Helsinki University Central Hospital, Helsinki, Finland. paivi.nevalainen@helsinki.fi
Päivi
P
Nevalainen
Elina
E
Pihko
Helena
H
Mäenpää
Leena
L
Valanne
Lauri
L
Nummenmaa
Leena
L
Lauronen
D000293:Adolescent; D002547:Cerebral Palsy / Q000473:pathology*; D002648:Child; D004338:Drug Combinations; D004558:Electric Stimulation; D004997:Ethinyl Estradiol; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000294:innervation; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009640:Norethindrone; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time; D013003:Somatosensory Cortex / Q000503:physiopathology*; D014110:Touch / Q000502:physiology*
D004338:Drug Combinations; C020416:norethindrone acetate, ethinyl estradiol, ferrous fumarate drug combination; D004997:Ethinyl Estradiol; D009640:Norethindrone