Handedness of children determines preferential facial and eye movements related to hemispheric specialization.
BACKGROUND
Despite repeated demonstrations of asymmetries in several brain functions, the biological bases of such asymmetries have remained obscure.


OBJECTIVE
To investigate development of lateralized facial and eye movements evoked by hemispheric stimulation in right-handed and left-handed children.


METHODS
Fifty children were tested according to handedness by means of four tests: I. Mono-syllabic non-sense words, II. Tri-syllabic sense words, III. Visual field occlusion by black wall, and presentation of geometric objects to both hands separately, IV. Left eye and the temporal half visual field of the right eye occlusion with special goggles, afterwards asking children to assemble a three-piece puzzle; same tasks were performed contra-laterally.


RESULTS
Right-handed children showed higher percentage of eye movements to right side when stimulated by tri-syllabic words, while left-handed children shown higher percentages of eyes movements to left side when stimulated by the same type of words. Left-handed children spent more time in recognizing non-sense mono-syllabic words. Hand laterality correlated with tri-syllabic word recognition performance. Age contributed to laterality development in nearly all cases, except in second test.


CONCLUSIONS
Eye and facial movements were found to be related to left- and right-hand preference and specialization for language development, as well as visual, haptic perception and recognition in an age-dependent fashion in a complex process.
Arteaga
Carmina
C
Laboratory of Cognitive Neurophysiology, Nacional Institute of Rehabilitation, México City, Mexico.
Poblano
Adrián
A
D002648:Child; D003430:Cross-Sectional Studies; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D007804:Language Development; D007807:Language Tests; D016015:Logistic Models; D008297:Male; D011597:Psychomotor Performance; D011930:Reaction Time; D014794:Visual Fields / Q000502:physiology*