Sign language and the brain: a review.

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Spoken language processing is predominantly lateralized to the left hemisphere (LH) in native speakers.
• Understanding the neural basis of signed language is crucial for a comprehensive theory of human language.
• Investigating sign language processing offers insights into the brain's capacity for language regardless of modality.

Purpose of the Study:

• To review current research on brain processing of signed languages.
• To compare neural mechanisms of sign and speech processing.
• To examine the lateralization of signed language in the brain.

Main Methods:

• Review of neuroimaging studies (e.g., fMRI, EEG) on sign language processing.
• Comparison of findings across studies investigating signers and speakers.
• Analysis of methodologies used to study brain activity during language tasks.

Main Results:

• Evidence suggests that signed language processing is also largely lateralized to the left hemisphere in native signers.
• Some studies indicate potential right hemisphere involvement in sign language processing, possibly exceeding that in speech processing.
• Methodological challenges exist in definitively answering the lateralization question for signed languages.

Conclusions:

• Signed language processing shares similarities with spoken language processing, particularly regarding left hemisphere dominance.
• The extent of right hemisphere involvement in sign language processing warrants further investigation.
• Future research should focus on refining methodologies to clarify the precise neural networks underlying signed language comprehension and production.