Somatosensory mismatch negativity in healthy children.
OBJECTIVE
Event-related potentials (ERPs) obtained when focused attention is kept away from the stimulus (unnoticed stimulation) are possibly linked to automatic mismatch-detection mechanisms, and could be a useful tool to investigate sensory discrimination ability. By considering the high impact of impaired somatosensory integration on many neurological disturbances in children, we aimed to verify whether mismatch-related responses to somatosensory stimulation could be obtained in healthy children.


METHODS
Eleven healthy participants (age range 6-11y, mean 8y 2mo, SD 1y 7mo; seven males, four females) underwent 'oddball' electrical stimulation of the right hand (80% frequent stimuli delivered to the thumb, 20% deviant stimuli delivered to the fifth finger). Data were compared with those obtained when the frequent stimuli to the thumb were omitted ('standard-omitted' protocol). ERPs were recorded at frontal, central, and parietal scalp locations. Children's overt attention was engaged by a demanding video game.


RESULTS
In the oddball protocol, deviant stimulation elicited a left central negativity at about 160ms latency, followed by a left frontal negative response at about 220ms latency. Standard-omitted traces showed only a left parietal negative response spreading to right parietal regions.


CONCLUSIONS
Mismatch-related somatosensory responses can be reliably obtained in children, providing that appropriate technical contrivances are used. In clinical use, the frontal components, which are present only during the oddball protocol, could be a reliable and unequivocal neurophysiological marker of the automatic mismatch-detection mechanism.
Restuccia
Domenico
D
IRCCS La Nostra Famiglia - E Medea, Polo Friuli Venezia Giulia, Udine, Italy. restuccia@pp.lnf.it
Zanini
Sergio
S
Cazzagon
Monica
M
Del Piero
Ivana
I
Martucci
Lucia
L
Della Marca
Giacomo
G
D000704:Analysis of Variance; D001364:Awareness / Q000502:physiology; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D002648:Child; D002657:Child Development / Q000502:physiology*; D003265:Contingent Negative Variation / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D012016:Reference Values; D055698:Touch Perception / Q000502:physiology