Premium
Does obstetric brachial plexus injury influence speech dominance?
Author(s) -
Auer Tibor,
Pinter Sandor,
Kovacs Norbert,
Kalmar Zsuzsanna,
Nagy Ferenc,
Horvath Reka A.,
Koszo Balazs,
Kotek Gyula,
Perlaki Gabor,
Koves Maria,
Kalman Bernadette,
Komoly Samuel,
Schwarcz Attila,
Woermann Friedrich G.,
Janszky Jozsef
Publication year - 2009
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.21538
Subject(s) - lateralization of brain function , laterality , gesture , psychology , dominance (genetics) , left and right , medicine , functional magnetic resonance imaging , audiology , cognitive psychology , neuroscience , linguistics , philosophy , biology , biochemistry , structural engineering , engineering , gene
Objective Right‐handedness and left‐sided language lateralization is an unresolved mystery with unknown cause/effect relations. Most studies suggest that the language lateralization is related to a fundamental brain asymmetry: right‐handedness may be secondary. We analyzed the possibility of an opposite cause/effect relation: whether asymmetric hand usage (as a cause) can influence language lateralization (as a consequence). Methods We determined language lateralization by functional magnetic resonance imaging in 15 subjects whose upper limb (UL) had been injured at birth because of unilateral damage of the brachial plexus. These subjects were able to use only one (the noninjured) UL perfectly. Results We found correlation between the severity of right‐sided UL injuries and hand usage dysfunction and the degree of left‐to‐right shift of language lateralization. There was, however, not a complete switch of language lateralization. Interpretation Right‐sided UL injury can induce a left‐to‐right shift in language lateralization, suggesting that hand usage can influence language lateralization. These findings may contradict the broadly accepted theory that right‐handedness is a secondary phenomenon caused by left‐sided hemispheric language lateralization. However, the cause/effect problem between asymmetric hand usage and language lateralization is not resolved in this study. Our findings may support the theory that gestures had a crucial role in human language evolution and is a part of the language system even today. Ann Neurol 2009;65:57–66