Abstracts

RATIONALE: Handedness (defined as the hand used in writing) is often used to predict whether a surgical patient is likely to have typical (left) or atypical (right, bilateral) representation of speech on the IAP. However, the value of footedness (defined as the foot used to punt an American football) in this context has not been explored.
METHODS: Patients were a consecutive series of 760 children and adults who over a 26 year period had valid IAPs and who had received neuropsychological evaluations including the Lateral Dominance Examination (Reitan RM, Wolfson D. The Halstead-Reitan Neuropsychological Test Battery, 2nd ed. Tucson, AR USA: Neuropsychology Press, 1993). This examination is not a questionnaire; it requires each patient to actually demonstrate how each unimanual and unipedal task is performed, and there are no [dsquote]ambidextrous[dsquote] patients by this system as people consistently write with one particular hand and kick with one particular foot. Most patients were candidates for cortical resection surgery for epilepsy. In handedness, 619 (81.4%) were right-handed (RH) and 141 (18.6%) were left-handed (LH). In footedness, 655 (86.2%) were right-footed (RF) and 105 (13.8%) were left-footed (LF). In combination, 592 (77.9%) were RH/RF, 88 (11.6%) were either RH/LF or LH/RF, and 80 (10.5%) were LH/LF.
RESULTS: Handedness alone highly predicted speech lateralization (Fisher[ssquote]s Exact: p=3x10-28) with 7.1% of RH having atypical (right, bilateral) speech and 46.1% of LH having atypical speech. However, footedness alone was also highly predictive with 8.5% of RF having atypical speech and 50.5% of LF having atypical speech (Fisher[ssquote]s Exact: p=2x10-26). When handedness and footedness were simultaneously considered, the best predictions were made: RH/RF, 6.9% atypical speech; RH/LF or LH/RF, 19.3% atypical speech; LH/LF, 63.8% atypical speech (Fisher[ssquote]s Exact: p=6x10-33). Also, a simultaneous consideration of footedness along with handedness led to a better prediction than handedness alone of whether atypical speech, when present, was likely to be right or bilateral.
CONCLUSIONS: Footedness is easily obtained and is of definite assistance to handedness in predicting both the presence of atypical speech and, when present, whether that atypicality is more likely to be right or bilateral. Why footedness should be so closely related to speech lateralization is of interest, and the possibilities for this are discussed.
Support: No funding.