GENDER DIFFERENCES IN OCCURRENCE OF LEFT-HANDEDNESS AND ATYPICAL SPEECH LATERALIZATION IN RESPONSE TO NEUROLOGICAL INSULTS DURING THE DEVELOPMENTAL PERIOD
Abstract number :
2.333
Submission category :
Year :
2003
Submission ID :
3710
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
John W. Miller, Suman Jayadev, Carl B. Dodrill Regional Epilepsy Center, University of Washington, Seattle, WA; Neurology, University of Washington, Seattle, WA; Neurological Surgery, University of Washington, Seattle, WA
Early life developmental insults may modify hemispheric lateralization of brain functions. Left-handedness (preferential use of the left hand for writing and other motor tasks), is a normal variant but also occurs in response to neurological insults ([quot]pathological left-handedness[quot]). In contrast, atypical speech (bilateral or right hemispheric speech lateralization) as determined by the intracarotid amobarbital procedure (IAP) is rare with a normal developmental history (Neurology 60:1042, 2003). The purpose of this study is to determine if there are gender differences in the tendency for hemispheric lateralization to be modified in response to developmental insults. This was done by comparing the incidence of left-handedness and atypical speech in patients with a clear history of a temporally discrete, well-defined insult to the central nervous system.
A database of 836 IAPs undertaken from 1974-1999 was reviewed. From this, 170 patients (85 female, 85 male) were selected based on criteria of a known history of a temporally well defined neurological insult (CNS infection or traumatic brain injury), and clear documentation of absence of any prior neurological symptoms.
Atypical speech was more common in females overall (19 vs. 5, p=0.003, Fisher[apos]s Exact). Most had a history of a neurological insult at age 5 or before (14/48 female, 3/34 male), and all had neurological insults before age 16 (19/67 female, 5/52 male). In addition, left-handedness was also much more common in females (26 vs. 10, p=0.004). Most left-handed patients had a neurological insult before age 6 (20/48 female, 7/34 male) and age 16 (23/67 female, 10/52 male) The occurrence of an abnormal neurological examination was similar in the two groups (20 female, 17 male, p=0.575), and was more commonly seen in patients with left-handedness (13/35) and atypical speech (11/23).
These results demonstrate that females are far more likely to have altered hemispheric lateralization in response to early life neurological insults. This suggests that there may exist a remarkable gender difference in the plasticity of functional cortical organization.