Handedness, symptom reporting, and accident susceptibility

Accident proneness, laterality, and time estimation

Cerebral laterality has been linked to accident proneness and time perception, but the possible role of time estimation abilities has received little attention. Accordingly, the present study focused on this under-explored question while also aiming to replicate past work examining the relationship between measures of laterality and injury proneness. Participants reported on the number of accidents they have had in their lifetime requiring medical care and the number of minor accidents they had in the past month as outcome variables. They also completed the Waterloo Handedness Questionnaire, a left bias visual task (Greyscales task), a right bias auditory verbal task (Fused Dichotic Words Task), and an objective measure of time perception. Extensive examination of statistical model fit showed that a model assuming a Poisson distribution provided the best fit for minor injuries and an additional negative binomial provided the best fit to the lifetime accidents. Results showed a negative relation between the degree of verbal laterality (absolute right bias) and injuries requiring medical care. Furthermore, the number of accidents requiring medical care was positively related to the precision of time estimation and the direction of verbal laterality on response time (raw right bias). Interpretations of these findings emphasize their implications for interhemispheric communication and motor control in the context of time estimation and auditory verbal laterality. These aspects seem to provide promising avenues for future research.

Reactivity in pain-free subjects and a clinical pain population: evaluation of the Kohn Reactivity Scale-dutch Version

BACKGROUND

Patients with pain are more reactive to various types of sensations, not limited to pain alone. A potential useful instrument to assess reactivity is the Kohn Reactivity Scale (KRS). This study examines the psychometric characteristics of the KRS-Dutch version and its ability to differentiate between subjects with and without pain.

METHODS

Internal consistency, convergent validity, and test-retest reliability of the Dutch translation of the KRS were assessed in 321 pain-free control subjects and different subgroups of this sample. Subsequently, reactivity scores were compared between the pain-free subjects and 291 pain patients who were referred to a pain clinic for treatment.

RESULTS

Reliability analyses indicated good internal consistency (α ≥ 0.77) and high test-retest reliability (intraclass correlation = 0.95) of the KRS in the control subjects. Validity analyses yielded positive correlations of the KRS with related constructs like pain vigilance and awareness (r = 0.37), symptom severity (r = 0.29), and the personality characteristic neuroticism (r = 0.20). Pain patients had overall significantly higher KRS scores than the pain-free subjects indicating increased reactivity, particularly for the patients with medically unexplained pain.

CONCLUSIONS

These findings indicate that the KRS is a useful instrument to screen for reactivity in pain patients, which may be of particular relevance for those suffering from medically unexplained pain.

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.

Hand preference and accidents in India

The relationship between handedness and accidents in self-classified left- and right-handers in India was examined. It was hypothesised that the incidence of accidents would be greater in left-handers as compared to right-handers. Data were collected with the help of a questionnaire on side bias, along with a checklist on accidents. Analysis of data suggested that whether or not left-handers have more accidents than right-handers depends on the kind of activity examined: in India, left-handers have more driving accidents than right-handers, while right-handers have more sports accidents than left-handers.

Laterality and accident proneness: A study of locomotive drivers

This study attempted to find the association between four measures of laterality (handedness, footedness, eyedness, and earedness) and accident proneness in locomotive drivers. The Sidedness Bias Schedule was administered to a sample of 80 locomotive drivers to ascertain their preferential bias. Their accident records were also available. Positive correlations were mostly found between the measures of hand, foot, ear, and eye dominance. Analyses suggested that there was a higher accident rate among left-handers and left-footers, with multiple regression unable to determine whether handedness or footedness was related more strongly to accident proneness. However, it was clear that accident rate was primarily associated with direction of lateralisation, and not with degree of lateralisation. Drivers with left-handedness were more likely to be involved in accidents, and it is possible that that may be related to the design of the locomotive cabs.

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.

Side bias and accidents: are they related?

This study purports to examine the role of different forms of side bias, handedness, footedness, eyedness, and earedness, in eliciting accident-proneness in individuals. A representative sample (N = 150) was administered a Side Bias Questionnaire (Handedness: 22 items, footedness: 5 items, eyedness: 5 items, earedness: 5 items) to ascertain their preferential bias. The questionnaire also required subjects to report the number of accidents committed during their lifetime while performing activities like sports, driving, household work, etc., that required attention of medical professionals. Regression analysis of data indicated that accident-prone behavior was significantly predicted from handedness. Analysis of variance, 3 (Accident groups: low, moderate, high) x 4 (Side bias: hand, foot, eye, ear), indicated that 'mixed' handers committed more accidents as compared with clear handers. The other forms of side bias, foot, ear, and eye were unrelated to frequency of accidents.

Performance Asymmetries in Computer Mouse Control of Right-Handers, and Left-Handers with Left- and Right-Handed Mouse Experience

Precision and general computer mouse aiming performance by right-handers (RH-RM) and left-handers with right-handed mouse experience (LH-RM) and by left-handers with left-handed mouse experience (LH-LM) were compared. A number of performance measures, such as reaction time, time to reach a target, time to click on target, and cursor trajectory, were analyzed. Superficially, specific hand experience seemed to dictate performance asymmetries, but a closer look revealed interactions between hand preference and hand performance. That finding has implications for theories of handedness. In addition, precision and general directional aiming with the mouse cursor showed a clear right hand superiority in reaction time in both RH-RM and LH-RM subjects, whereas LH-LM subjects showed no lateral asymmetries. Finally, the overall time taken for the task, averaged across groups and conditions, favored the experienced hand by some 180 ms. In practical terms, that is not a large difference, especially because the difference will be reduced with practice. Thus, the use of the inexperienced hand can be advocated when there is a need to forestall or ameliorate repetitive stress in the experienced hand.

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

Several recent studies suggest that left-handers have higher susceptibility to accidental injury. Two studies investigated the suggested link between sinistrality and accidental injury by assessing the prevalence of joint problems, bone breaks, and fractures, which may be the sequelae of such mishaps. Study 1 used retrospective responses on medical history checklists completed by 1064 males on active duty with the United States Air Force. It found that left-handers were at significantly higher risk for knee problems (RR = 2.74), elbow and shoulder problems (RR = 3.03), and also swollen and painful joints (RR = 1.87), although there was no difference in the incidence of broken bones. Study 2 used an expanded handedness scale and retrospective reports of both bone breaks and fractures in a predominantly university sample of 1716 (975 women, 741 men) with median age of 20 years, and demonstrated that non-right-handers were at greater risk for bone breaks and fractures (RR = 1.24). As joint problems, as well as bone breaks and fractures, are often the aftermath of accidents that result in falls or collisions with unyielding objects, the fact that left-handers are more likely to suffer from these problems is consistent with the suggestion that sinistrals are more susceptible to accident-related injuries.