Visual field asymmetries in congenitally deaf and hearing children

Vargha‐Khadem, Faraneh

doi:10.1111/j.2044-835x.1983.tb00910.x

Cited by 11 publications

(9 citation statements)

References 23 publications

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“…In contrast, deaf subjects showed inconsistent and reduced patterns of hemispheric asymmetry in response to linguistic and affective facial expression stimuli. Vargha-Khadem (1983) reported a right-visual field superiority for face identif ication in deaf children, a pattern opposite that found for hearing children. These studies suggest that for hearing nonsigners, the right-hemisphere may predominate in the recognition of all forms of facial expression.…”

Section: Background Studies Of Facial Expression In Aslmentioning

confidence: 78%

Neuropsychological Studies of Linguistic and Affective Facial Expressions in Deaf Signers

1999

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For deaf users of American Sign Language (ASL), facial behaviors function in two distinct ways: to convey affect (as with spoken languages) and to mark certain specific grammatical structures (e.g., relative clauses), thus subserving distinctly linguistic functions in ways that are unique to signed languages. The existence of two functionally different classes of facial behaviors raises questions concerning neural control of language and nonlanguage functions. Examining patterns of neural mediation for differential functions of facial expressions, linguistic versus affective, provides a unique perspective on the determinants of hemispheric specialization. This paper presents two studies which explore facial expression production in deaf signers. An experimental paradigm uses chimeric stimuli of ASL linguistic and affective facial expressions (photographs of right vs. left composites of posed expressions) to explore patterns of productive asymmetries in brain-intact signers. A second study examines facial expression production in left and right brain lesioned deaf signers, specifying unique patterns of spared and impaired functions. Both studies show striking differences between affective and linguistic facial expressions. The data indicate that for deaf signing individuals, affective expressions appear to be primarily mediated by the right-hemisphere. In contrast, these studies provide evidence that linguistic facial expressions involve left hemisphere mediation. This represents an important finding, since one and the same muscular system is involved in two functionally distinct types of facial expressions. For hearing persons, the right-hemisphere may be predominant in affective facial expression, but for deaf signers, hemispheric specialization for facial signals is influenced by the purposes those signals serve. Taken together, the data provide important new insights into the determinants of the specialization of the cerebral hemispheres in humans.

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Section: Background Studies Of Facial Expression In Aslmentioning

confidence: 78%

Neuropsychological Studies of Linguistic and Affective Facial Expressions in Deaf Signers

1999

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“…The importance of facial gestures in ASL may increase the involvement of LH language and face perception regions in a range of face processing tasks. Previous studies have documented bilateral hemispheric or visual field processing in deaf signers during the perception of expressive faces (McCullough, et al, 2005; Szelag & Wasilewski, 1992; Szelag, Wasilewski, et al 1992) or a RVF asymmetry (Vargha-Khadem, 1983), while other work has documented that laterality is highly task rather than stimulus dependent for this population (Corina, 1989). We observed subtle differences in overall hemispheric asymmetry between deaf and hearing participants.…”

Section: Discussionmentioning

confidence: 98%

“…As in the Benton task studies, hearing native signers outperformed their nonsigning counterparts. Finally, behavioral (Szelag & Wasilewski, 1992; Vargha-Khadem, 1983) and fMRI studies (McCullough, Emmorey, et al 2005) showed that deafness and sign language use alters the typical left visual field/right hemispheric lateralization of responses to faces, resulting in a more bilateral distribution. Thus, empirical evidence supports the notion that deafness and sign language use induce changes in behavioral and neural organization of face processing.…”

Section: Introductionmentioning

confidence: 99%

Behavioral and neural evidence of increased attention to the bottom half of the face in deaf signers

Mitchell

Letourneau

Maslin

2013

Restorative Neurology and Neuroscience

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Purpose This study examined the effects of deafness and sign language use on the distribution of attention across the top and bottom halves of faces. Methods In a composite face task, congenitally deaf signers and typically hearing controls made same/different judgments of the top or bottom halves of faces presented with the halves aligned or spatially misaligned, while event-related potentials (ERPs) were recorded. Results Both groups were more accurate when judging misaligned than aligned faces, which indicates holistic face processing. Misalignment affected all ERP components examined, with effects on the N170 resembling those of face inversion. Hearing adults were similarly accurate when judging the top and bottom halves of the faces, but deaf signers were more accurate when attending to the bottom than the top. Attending to the top elicited faster P1 and N170 latencies for both groups; within the deaf group, this effect was greatest for individuals who produced the highest accuracies when attending to the top. Conclusions These findings dovetail with previous research by providing behavioral and neural evidence of increased attention to the bottom half of the face in deaf signers, and by documenting that these effects generalize to a speeded task, in the absence of gaze shifts, with neutral facial expressions.

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“…Visual field studies suggested a redistribution of neural resources for face processing in deaf individuals, with a shift toward increased involvement of the left hemisphere (Corina, 1989; Vargha-Khadem, 1983). Thus, the linguistic salience of faces may lead to altered laterality for face processing in deaf signers.…”

Section: Introductionmentioning

confidence: 99%

Cortical plasticity for visuospatial processing and object recognition in deaf and hearing signers

Weisberg¹,

Koo²,

Crain³

et al. 2012

NeuroImage

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Experience-dependent plasticity in deaf participants has been shown in a variety of studies focused on either the dorsal or ventral aspects of the visual system, but both systems have never been investigated in concert. Using functional magnetic resonance imaging (fMRI), we investigated functional plasticity for spatial processing (a dorsal visual pathway function) and for object processing (a ventral visual pathway function) concurrently, in the context of differing sensory (auditory deprivation) and language (use of a signed language) experience. During scanning, deaf native users of American Sign Language (ASL), hearing native ASL users, and hearing participants without ASL experience attended to either the spatial arrangement of frames containing objects or the identity of the objects themselves. These two tasks revealed the expected dorsal/ventral dichotomy for spatial versus object processing in all groups. In addition, the object identity matching task contained both face and house stimuli, allowing us to examine category-selectivity in the ventral pathway in all three participant groups. When contrasting the groups we found that deaf signers differed from the two hearing groups in dorsal pathway parietal regions involved in spatial cognition, suggesting sensory experience-driven plasticity. Group differences in the object processing system indicated that responses in the face-selective right lateral fusiform gyrus and anterior superior temporal cortex were sensitive to a combination of altered sensory and language experience, whereas responses in the amygdala were more closely tied to sensory experience. By selectively engaging the dorsal and ventral visual pathways within participants in groups with different sensory and language experiences, we have demonstrated that these experiences affect the function of both of these systems, and that certain changes are more closely tied to sensory experience, while others are driven by the combination of sensory and language experience.

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Visual field asymmetries in congenitally deaf and hearing children

Cited by 11 publications

References 23 publications

Neuropsychological Studies of Linguistic and Affective Facial Expressions in Deaf Signers

Neuropsychological Studies of Linguistic and Affective Facial Expressions in Deaf Signers

Behavioral and neural evidence of increased attention to the bottom half of the face in deaf signers

Cortical plasticity for visuospatial processing and object recognition in deaf and hearing signers

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