Handedness in Swedish 10-year-olds. Some background and associated factors.
Forty-five left-handed and 46 right-handed 10-year-old children were subjected to a limited set of neurological tests and a square tracing task. 'Pathological' handedness was diagnosed in cases showing poor performance with the non-preferred hand on the squares task. The frequency of left-handedness in the population was estimated at 9.2%. The boy : girl ratio was 1.6:1. 'Pathological' handedness was twice as common among left-handers as among right-handers. Neurological dysfunction was more common in 'pathological' handers, especially left-handers. Reduced pre-. peri- and neonatal optimality was seen in boys with 'pathological handedness'. School achievement problems and behaviour problems were much more common in left-handed boys than in other study groups. The results lend partial support for the extended pathological left-handedness model recently hypothesized by Bishop, but it is suggested that left-handedness in boys is more often a symptom of pathological shift of handedness than is left-handedness in girls.
D000124:Achievement; D001925:Brain Damage, Chronic / Q000523:psychology*; D002648:Child; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000523:psychology; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications; D011597:Psychomotor Performance; D012737:Sex Factors; D013548:Sweden