Left-handedness.

Abstract

The phenomenon of left-handedness is reviewed from prehistoric man through contemporary studies of lateralization of cerebral function. The following conclusions seem warranted: Handedness is most appropriately regarded as a continuum ranging from strong right-handedness across mixed-handedness to strong left-handedness. Left-handedness, ranging from moderate through strongly lefthanded, is found in approximately 10% of the population. Evidence for a genetic basis of handedness remains positive, but with no direct link established. There is remarkably little evidence for any association of left-handedness with deficit, as has often been suggested. The familial left-handed show greater recovery of functioning following unilateral cerebral insult than do nonfamilial right-handed and nonfamilial left-handed. Both behavioral and clinical lesion studies indicate systematic differences in lateralization of cerebral function between the right-and left-handed and the familial and nonfamilial left-handed. A classification of handedness and lateralization of cerebral function is suggested, with the right-handed with no family history of left-handedness being the most strongly lateralized and the left-handed with a positive family history of left-handedness showing bilateral localization of functions. The left-handed with no family history of left-handedness are classified as identical in cerebral lateralization with the right-handed with no family history of left-handedness. The possibilities exist that bilaterality of cerebral functioning is either stable in the human race or is changing at an extremely slow rate.In the Old Testament, in the Book of Lord's left hand, what part, if any, it played Psalms (Joint Committee on the New Trans-in the creation of the heavens, and who is lation of the Bible, 1970), the statement is held in the left hand. However, in the New made that the Lord's "right hand is full of Testament, the Book of Matthew (Joint righteousness" (48:10); in the Book of Isaiah, Committee, 1970) provides some fairly specific that his "right hand shall spread out the information on the fate of those individuals heavens" (48:13); and again in Psalms, that at the left hand: his "right hand shall hold me" (139:10). c . ,. , , "",, /-\u rn i i.-j -c. When the Son of Man comes in his glory and allThe Old Testament provides no specific the angels with ^ he will sit in gtate * n 4 thronC| information as to what is contained in the w ; t h all the nations gathered before him. He will separate men into two groups, as a shepherd separates the sheep from the goats and he will place the sheep This work was supported in part by , funds from on his right hand and the goats on his left. Then the Spencer Foundation and from the Committee on the king will say to those on his right hand, "You

Hand Dominance and Blood Group: Association in Epistaxis

“…Hussain et al [11] showed 71.6 % cases presented with anterior bleed which is in concordance with our study (69.4 %). In the earlier studies by Joice et al [12] and Hardyck et al [13] no significant association was found between side of nasal bleeding and hand dominance but the present study showed highly significant (p = 0.001) association between right handedness and left sided nasal bleed.…”

Hemispheric lateralization and handedness correlation of human evoked “steady-state” responses to patterned visual stimuli

“…Psychophysiological studies support the hypothesis that visual input is lateralized and correlated with handedness (reviewed by Hardyck & Petrinovich, 1977). The reviewers suggest that lateralization of visual function is organized along a continuum of handedness.…”

Long-term stability of electroencephalographic asymmetry and power in 3 to 9 year-old children

“…In adults, sex was found to be unrelated to stability of EEG asymmetry (Vuga et al, 2006). Handedness may be an important factor influencing stability due to the differential brain organization of left and right handed individuals (Galaburda et al, 1990;Hardyck & Petrinovich, 1977). In prior studies of frontal EEG asymmetry with children, handedness was either restricted to right-handers or ignored (Rybak et al, 2006;Santesso et al, 2006;Shankman et al, 2005).…”