Handedness as a Predictor of Increased Risk of Knee, Elbow, or Shoulder Injury, Fractures and Broken Bones

In praise of ambidexterity: How a continuum of handedness predicts social adjustment

This paper estimates the relationship between handedness and social adjustment in children. In addition to binary measures of hand preference, we also use a continuous measure of relative hand skill. Outcomes at ages 7, 11 and 16 are studied. The data used is the British 1958 Birth. Using a partially linear semi-parametric regression estimator, it is shown that non-right-handedness (as hand preference) is associated with poorer social adjustment but this effect weakens as individuals age into their teens. The continuous measure of hand skill has a non-monotonic effect on social adjustment with poorer social adjustment in the tails of the continuum. The results are consistent with a growing body of evidence which shows that it is the consistency or degree of laterality (rather than direction) that is important for many outcomes.

Establishing hand preference: why does it matter?

Hand preference has been associated with psychological and physical well-being, risk of injury, pathological irregularities, longevity, and cognitive function. To determine hand preference, individuals are often asked what hand they use to write with, or what hand is used more frequently in activities of daily living. However, relying only on one source of information may be misleading, given the strong evidence to support a disassociation between self-reported hand preference and outcomes of hand performance assessments. This brief communication is intended to highlight the various methods used to determine hand preference, to discuss the relationship between hand preference inventories and performance measures and to present some recent findings associated with hand preference and musculoskeletal disorders.

Differences by Sex and Handedness in Right and Left Femur Bone Mineral Densities

Left-handedness was reported to be a risk factor for accident-related injuries, head injuries, traumatic brain injuries, sport-related injuries, and bone breaks and fractures. As decreased bone mineral density is a good marker of bone fractures, the femoral bone mineral densities of normal left-handed university students were compared with those of right-handed students. Hand preference of 66 men and 47 women was assessed using the Edinburgh Handedness Inventory. Measures of bone mineral density with a Hologic QDR-4500W (S/N 48403) densitometer showed bone mineral densities of both right and left proximal femur regions were higher in right-handed than in left-handed students. These results are consistent with the claim that left-handed participants had higher trauma and injury risk. Also, these results may explain the sex-related differences by handedness for susceptibility in accident-related injuries such as bone fractures.

The effects of hand preference side and hand preference switch history on measures of psychological and physical well-being and cognitive performance in a sample of older adult right-and left-handers

Claims have been made that left-handedness often arises from pathological causes, and that owing to this underlying pathology, the presence of sinistrality may entail disadvantages for both the length and quality of life. A prime implication of these claims is that left-handers, as a group, should display signs of poorer fitness than right-handers. This poorer fitness might take the form of an increased incidence of illnesses and/or accidents. In addition, it might also be predicted that left-handers would experience a psychological and, perhaps, cognitive quality of life that is inferior to that of right-handers. In the present study, we measured a large sample (N=1277) of older adults on four indexes of lateral preference (hand, foot, eye, and ear), on whether or not they experienced pressure to switch their preferred writing hand, and variables related to psychological well-being, physical health, and cognitive performance. The results revealed that the presence of left hand writing, in isolation, did not predict decreases in quality of life factors; however, in conjunction with left-handed writing, the presence of a hand preference switch report was shown to be important. In particular, one subset of left-handers-those who attempted to change their preferred writing hand but were unsuccessful-was found to have a lower quality of psychological and physical well-being on multiple measures.

The Specificity of Motor Skill and Manual Asymmetry: A Review of the Evidence and Its Implications

Results of investigations on gaining control of limb movements are reviewed, and their contribution to understanding the development of manual asymmetries is discussed in relation to the discrimination and programming of appropriate neuromuscular resources. An examination of the relevant evidence on number and types of manual asymmetries recorded provides strong grounds for concluding that where asymmetries occur, they simply represent a further example of the well-documented activity-specific nature of motor skills and of the extremely lengthy periods of learning or experience needed for their acquisition and perfection. This specificity of motor skill and manual asymmetry also readily accounts for most of the discrepancy usually reported between assessments of hand preference and performance differences between hands, because these alternative measures of handedness have rarely employed the same range or variety of tasks.