Levy and Reid's neurological model in relation to writing hand/posture: An evaluation.

Abstract

Levy and Reid's neurological model proposes that (a) writing hand/posture is predictive of cerebral lateralization of verbal and spatial functions, (b) both inverted and normal writing postures are directly controlled by the languagedominant hemisphere via ipsilateral pyramidal tracts for inverters and via contralateral pyramidal tracts for normals, and (c) inverted posture is due to this ipsilateral pyramidal control and to partial agenesis of the corpus callosum. This model is evaluated in light of the relevant empirical literature and a critical appraisal of Levy and Reid's own theoretical rationale. It is concluded that Levy and Reid's neurological model in relation to writing hand/posture does not receive conclusive or unqualified support from the empirical evidence. Nevertheless, though their model should not be accepted in its original form, it has provided the framework for a number of profitable areas of research that demand further investigation.

The integrative action of the cerebral hemispheres

“…Factors such as sex, handedness (e.g., Jones, 1980b;Levy & Reid, 1978), and perhaps writing style (Levy & Reid, 1978; but see Weber & Bradshaw, 1981) that are probably responsible for the general variation in hemispheric specialization were controlled in the experiments. So, too, were the factors thought to be responsible specifically for variation in lateralization of letter identification.…”

A review of handwriting research: Progress and prospects from 1980 to 1994

“…Forensic investigations of handwriting (Halder-Sinn, 1991) and studies of graphology (e.g., Wing, Watts, and Sharma, 1991) were not reviewed. Also excluded were reports examining the relationship between writing hand-posture and cerebral lateralization of function (e.g., Weber and Bradshaw, 1981) and medication trials where handwriting was used as a dependent variable (Whalen, Henker, and Finck, 1981). Finally, studies comparing compositions produced via handwriting and word processing were not included.…”

Further evidence of the absence of measurable interhemispheric transfer time in left-handers who employ an inverted handwriting posture

“…Studies testing the hypothesis of cognitive function laterality differences between IHP and NHP sinistrals have reported generally negative results (see Weber & Bradshaw, 1981). Studies addressing the hypothesis of differing motor pathway dominances in the two handwriting-posture groups are somewhat more consistent.…”