Handedness of children determines preferential facial and eye movements related to hemispheric specialization

Abstract

-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. Method: 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 contralaterally. 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. Conclusion: 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.KEY WORDS: handedness, language, haptic perception, visual perception, left and right hemispheres, brain specialization.La lateralidad manual determina la preferencia motora ocular y facial en relación con la especialización hemisférica en niños Resumen -Contexto: A pesar de las repetidas demostraciones de asimetría en varias funciones cerebrales, sus bases biológicas permanecen no bien conocidas aún. Objectivo: Investigamos el desarrollo de la lateralización de los movimientos faciales y oculares provocados por la estimulación hemisférica preferencial en niños diestros y zurdos. Método: Se examinaron 50 niños que se dividieron de acuerdo a su lateralidad manual, se les aplicaron 4 pruebas: I. Discriminación de palabras mono-silábicas sin-sentido, II. Palabras tri-silábicas con sentido III. Oclusión mono-ocular y discriminación táctil de figuras geométricas por cada mano. IV. Oclusión del ojo izquierdo y de la mitad temporal del campo visual derecho y después contralateralmente solicitando al niño armar un rompecabezas de 3 piezas. Resultados: Los niños diestros mostraron un mayor porcentaje de movimientos oculares hacia la derecha cuando se les estimuló con palabras trisilábicas, mientras los zurdos presentaron más movimientos oculares hacia la izquierda con el mismo tipo de palabras. Los niños zurdos usaron más tiempo para reconocer las palabras monosilábicas sin sentido. La lateralidad correlacionó con la discriminación de palabras trisilábicas. La edad contribuyó significativamente al desarrollo de la lateralidad en todas las pr...

Performance comparison between right-handers and left-handers in a Brazilian sample of the Developmental Neuropsychological Assessment

“…As for hand preference associated with gender, there was no significant difference, which corroborates the studies of Arteaga and Poblano (2008), Beratis et al (2009) and Preti et al (2014). Other authors (Johnston et al, 2007;Milenkovi et al, 2013) found a prevalence of left-handed men.…”

“…Left-handers presented a poorer performance than right-handers in the total semantic score (sum of animal, food and beverage categories) (p = 0.002). As well as the findings of Arteaga and Poblano (2008), in which left-handers took longer to recognize monosyllabic pseudowords and discriminated fewer trisyllabic words, the hypothesis is that incomplete hemispheric specialization may interfere with skills involving language in left-handers. Siengthai, KritzSilverstein, and Barrett-Connor (2008), in crosssectional study with the elderly, found that lefthanded women have lower verbal fluency than right-handers.…”

“…The hypothesis of Arteaga and Poblano (2008) for hemispheric asymmetry development should also be emphasized. Considering the results of the subtests in the language domain, there were significant differences in verbal fluency subtest, WG.…”

“…The left premotor cortex was activated more than the right premotor cortex in non-manual action verbs in right-handers. The opposite occurred with left-handers (Casasanto, Williems, & Hagoort, 2010).´ When investigating 50 healthy children between the ages of 8 and 10, Arteaga and Poblano (2008) found that left-handers take longer to recognize monosyllabic pseudowords and discriminate fewer trisyllabic words. The hypothesis for these results would be due to incomplete left hemispheric specialization for language and possible difficulties would include verbal fluency, decoding and language processing speed.…”

“…For over a century, the relationship between the Left Hemisphere (LH) and language has been associated with the human brain hemispheric asymmetry (Arteaga & Poblano, 2008;Willems, Van der Haegen, Fisher, & Francks, 2014). In right-handed individuals, 97% present linguistic dominance in the LH and 3% in the Right Hemisphere (RH) or bilateral dominance.…”