Cross-cultural adaptation, validity and reliability of Turkish version of the Waterloo Handedness and Footedness Questionnaire-Revised

This study investigated the validity and reliability of Turkish versions of the Waterloo Handedness and Footedness Questionnaire-Revised (WHQ-R and WFQ-R). Turkish versions of the WHQ-R and the WFQ-R, and other assessments (the Handedness Questionnaire and the Footedness Preference Test) were applied to 444 healthy participants aged between 18 and 65 years. The translation and cultural adaptation process of the WHQ-R and the WFQ-R was provided by the following proposed guideline. For test-retest reliability, translated versions were re-applied to 88 participants in a 7-day interval. Cronbach's alpha of the WHQ-R was 0.984 and that of the WFQ was 0.905. The test-retest intra-class correlation coefficients (ICC) of the WHQ-R varied from 0.741 to 0.933 and those of the WFQ-R from 0.649 to 0.814. There were moderate to strong correlations between the WHQ-R and the Handedness Questionnaire (r = -853, p < 0.001) and between the WFQ-R and the Footedness Preference Test (r = -0.687, p < 0.001). Confirmatory factor analysis revealed a two-factor structure of the WHQ-R and the WFQ-R. The results of this study demonstrated that Turkish versions of the WHQ-R and the WFQ-R are reliable and valid inventories for assessing handedness and footedness in this population.

The Bias toward the Right Side of Others Is Stronger for Hands than for Feet

As shown by a series of previous studies, ambiguous human bodies performing unimanual or unipedal actions tend to be perceived more frequently as right-handed or right-footed rather than left-handed or left-footed, which indicates a perceptual and attentional bias toward the right side of others’ body. However, none of such studies assessed whether the relative strength of such a bias differs between the upper and lower limbs. Indeed, given that the prevalence of right-handedness is slightly larger than that of right-footedness, and given that hands provide more information than feet as regards both communicative and aggressive acts, it is plausible that the bias toward the right side of human bodies should be stronger for the hand than for the foot. We performed three experiments in each of which participants had to indicate the rotating direction (revealing the perceived handedness/footedness) of ambiguous human figures with either one limb (arm or leg) or two limbs (one arm and the contralateral leg) extended. The hypothesized advantage of the right hand over the right foot was found in both the second and the third experiment.

Four meta-analyses across 164 studies on atypical footedness prevalence and its relation to handedness

Human lateral preferences, such as handedness and footedness, have interested researchers for decades due to their pronounced asymmetries at the population level. While there are good estimates on the prevalence of handedness in the population, there is no large-scale estimation on the prevalence of footedness. Furthermore, the relationship between footedness and handedness still remains elusive. Here, we conducted meta-analyses with four different classification systems for footedness on 145,135 individuals across 164 studies including new data from the ALSPAC cohort. The study aimed to determine a reliable point estimate of footedness, to study the association between footedness and handedness, and to investigate moderating factors influencing footedness. We showed that the prevalence of atypical footedness ranges between 12.10% using the most conservative criterion of left-footedness to 23.7% including all left- and mixed-footers as a single non-right category. As many as 60.1% of left-handers were left-footed whereas only 3.2% of right-handers were left-footed. Males were 4.1% more often non-right-footed compared to females. Individuals with psychiatric and neurodevelopmental disorders exhibited a higher prevalence of non-right-footedness. Furthermore, the presence of mixed-footedness was higher in children compared to adults and left-footedness was increased in athletes compared to the general population. Finally, we showed that footedness is only marginally influenced by cultural and social factors, which play a crucial role in the determination of handedness. Overall, this study provides new and useful reference data for laterality research. Furthermore, the data suggest that footedness is a valuable phenotype for the study of lateral motor biases, its underlying genetics and neurodevelopment.

Dual-Task Performance in Right- and Left-Handed Adults: A Finger-Tapping and Foot-Tapping Study

The dual-task paradigm has been used extensively to study laterality, with concurrent verbalization interfering with right finger-tapping in right handers. Only a few studies have used this paradigm to study interference patterns in left handers and have found inconsistent results. The dual-task paradigm has not been used to study interference effects with concurrent verbalization and foot-tapping. The objective of this study was to use this paradigm to assess whether verbal interference produces different effects on finger- and foot-tapping rate for right handers as compared to left handers. 12 right-handed and 12 left-handed men were studied, each with uncrossed hand and foot dominance, i.e., all individuals were either right handed and right footed or left handed and left footed. Subjects performed finger- and foot-tapping tasks with and without verbal interference. A significant relationship was found between handedness and finger and foot-tapping rate; individuals with a stronger right-hand preference tended to tap at a higher rate on the right side and vice-versa. Analogous relationships were not found when participants were tapping and speaking concurrently. With verbal interference, both right and left handers had a significant asymmetric effect with a decremental response in right finger-tapping rate and a facilitative effect on left finger-tapping rate. In contrast, there was a bilateral decremental response in foot-tapping with verbal interference in both right and left handers. The implications of these findings are discussed with reference to cerebral laterality of language systems and to the differential organization and integration of the motor representations of the hand and the foot.

Survey of Korean pedestrians' natural preference for walking directions

The primary objective of this study was to investigate the stereotypes of Koreans regarding preferred walking directions when encountering various public walking facilities, and to provide useful information to pedestrians and traffic policy legislators. To this end, this study was conducted in two phases. In the first phase, we conducted observational research on pedestrians' walking directions in ten different situations. In the second phase, six hundred Korean male and female subjects were selected to investigate the various statistics about their preferred walking directions and their employment characteristics in diverse walking facilities. The results showed that 59.3% abided by the Left-side Traffic rule while 40.7% abided by the Right-side rule. On the contrary, 73.7% of respondents showed preferences to the Right-side Traffic rule. Moreover, right-handed people showed strong tendencies to walk on the right side of the road and vice versa, hence suggesting that the direction people naturally prefer in walking should be a crucial determinant when regulating traffic policies.

Spatial stimulus response compatibility for a horizontal visual display with hand and foot controls

In this study, two experiments were conducted to examine spatial stimulus-response compatibility (SRC) effects for a horizontal visual display with hand and foot controls. In experiment 1, the hand and foot controls were in a hands above and feet below vertical plane, such that the display and controls were orthogonal to each other. In experiment 2, the foot pedals were moved forward and placed directly underneath the front row of signals, resulting in an additional horizontal display and control relationship. The results of experiment 1 revealed a strong orthogonal SRC effect, such that the best performance was for the front signals with hand controls and rear signals with foot pedals, which was not altered with the presence of horizontal location mappings in experiment 2. These findings indicate that the front-hand/rear-foot mapping relationship was quite robust with regard to changes in the relative locations of the hand and foot response devices. STATEMENT OF RELEVANCE: The results of this study provide useful ergonomics recommendations for designing control consoles with visual signals presented in a horizontal plane and control devices operated by hands and feet. They are helpful for improving efficiency and overall system performance in person-machine systems.

Deriving estimates of contralateral footedness from prevalence rates in samples of Brazilian and non-Brazilian right- and left-handers

Although footedness is closely associated with handedness, accurate prevalence rates of contralateral footedness in right- and left-handed populations were previously unavailable to researchers studying the relationship between phenotypic and hemispheric asymmetries. We collected preference data from 2081 Brazilian children and adolescents, and relate the prevalence of crossed hand/foot preferences to values reported elsewhere in the literature. In our samples, about 4% of the dextrals and 33% of the sinistrals exhibited a contralateral kicking preference. This is in close agreement with the weighted means from our analysis of 19 papers in the literature, which yields 4.0% left-footed kicking in dextrals and 33.5% right-footed kicking in sinistrals. These values are in marked contrast to the 50% figure for right-footed kicking in sinistrals as given by MacNeilage and colleagues (1988, 1991). Among Brazilians with mixed handedness, there was a substantial increase in incongruent footedness. Male consistent right- and left-handers showed a higher prevalence of cross-footed preferences in their kicking preference than females. The sex difference in dextrals was attributed to a training effect in soccer-related activities, and to a sampling bias in sinistrals.

Hand dominance and hand use behaviour reported in a survey of 2437 Koreans

Most tools, utensils, office equipment, home appliances, clothes, medical instruments, sporting goods, weapons and public facilities are made for people who are right-handed. Many left-handed people have to endure a certain amount of inconvenience or difficulty in carrying out daily activities in such an environment. In this study, 2437 Korean male and female participants were randomly selected to collect a variety of data on hand dominance and hand preference when handling diverse products and facilities. Their responses in a questionnaire survey revealed that 5.8% were left-handed and 7.9% were ambidextrous. The younger participants who were from teens to 39 years reported higher percentages of left-handedness than those over 40 years, with those in their thirties reporting the highest proportion of left-handedness (7.3-7.6%) for both men and women. A slightly higher percentage of the male participants (5.9%) said that they were left-handed than did the female participants (5.6%). However, the percentage who were ambidextrous varied with age group, but overall there was a higher percentage of women (8.3%) than of men (7.6%). The analysis of hand use behaviour revealed that the right-handed and ambidextrous people had a tendency to use their right hands more for actions that required accuracy than those that required force. The left-handed people had a strong tendency to use their left hands more often when making a forceful action than for one that required accuracy. Derived from these results, the conclusion is that, depending on their hand dominance, people seem to use their hands differently when they handle objects or use facilities, which should be considered in the design of hand-controlled devices. Depending on which hand is the dominant one, people seem to use their hands differently when they handle objects or use facilities. The left-handed tend to use their left hands more with force-required motions than with accuracy-required motions, while ambidextrous and right-handed people use their right hands more with accuracy-required motions than with force-required motions. Designers of products and facilities will find the results of this study useful for developing hand-controlled devices and systems.

How Good People are at Estimating their Own Performance? A Study of the Relationship between Hand Preference and Motor Performance

This article examines the relationship between the awareness of hand preference and hand and foot performance among right-, left- and mixed-handers (n = 224). The hand preference was assessed using a handedness inventory. Hand and foot performances were measured using rapid index finger or toe tapping. A significant interaction between hand preference and the tapping rate indicated that in left-handers, left tapping was faster than right tapping and in right-handers, right tapping was faster than left tapping regardless of effector, finger or toe. The mixed-handers, however, did not show differences between left and right tapping performance. Correlations between performances were highest between hands or between feet. Also, hand performance was more strongly positively associated to foot performance in the mixed- and left-handers than right-handers. Similar inter-limb performance in mixed-handers tends to implicate inconsistent or undeveloped cerebral lateralisation. The results indicate that self-awareness of the pattern of hand use significantly relates to hand and foot performance.

Left-handed surgeons: are they left out?

BACKGROUND

Left-handedness has been considered a simple inconvenience by some or something as convoluted as "the sinister," the Latin word for the left, by others. One in ten medical personnel is left-handed. The perceptions of left-handed surgeons regarding their laterality related inconveniences are unknown.

OBJECTIVES

To determine the perceptions of left-handed surgeons and the way it has affected their surgical training and career.

DESIGN AND SETTING

Web-based survey of left-handed surgeons.

PARTICIPANTS

Left-handed surgeons in 2 boroughs of New York City, Manhattan and Brooklyn.

METHODS

Distribution and completion of the survey.

MAIN OUTCOME MEASURE

Career-oriented concerns of left-handed surgeons.

RESULTS

Three percent of left-handed surgeons received laterality related mentoring during medical school. Ten percent of the programs mentored left-handed surgical residents, and 13% of the programs provided left-handed instruments during surgical residency. Laparoscopy and laparoscopic instruments did not eliminate the problems associated with instrument handling to left-handed surgeons. Ten percent of the left-handed surgeons expressed concerns when asked whether they would be comfortable being treated by another left-handed surgeon when they are the patients themselves.

CONCLUSIONS

This study reveals the perceptions of left-handed surgeons in adapting to a right-handed world. Early laterality related mentoring in medical school and during surgical residency with provision of left-handed instruments might reduce the inconveniences of left-handed surgeons learning.

Footedness is a better predictor of language lateralisation than handedness

A tremendous amount of experimental work has attempted to identify a reliable behavioural predictor of language lateralisation. Preferred handedness has probably received the most attention, but there are some recent reports that preferred footedness may serve as a more reliable predictor. The present study sought to test this claim by selectively recruiting 32 participants such that the factors of handedness, footedness, and gender were completely crossed. Language lateralisation was assessed with the Fused Dichotic Words Test (FDWT), and lateral preference for both handedness and footedness was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred foot ( P <.001) but not with preferred hand ( P = .196). This result is problematic for evolutionary theories of cerebral lateralisation that claim left-hemispheric language is related to fine manual motor skill and sequencing. Language lateralisation may be more closely related to asymmetrical control of whole-body finely sequenced movements.

Inter- and intra-tester reliability of the Balance Performance Monitor in a non-patient population

BACKGROUND AND PURPOSE

There is a growing interest in the measurement and evaluation of balance deficits and a number of instruments for measurement are now available. However, few data exist that accurately describe the reliability when using these measurement tools. This study was designed to evaluate the inter- and intra-tester reliability of using the Balance Performance Monitor (BPM) (SMS Healthcare) in a non-patient population.

METHODS

A total of 58 subjects (mean age 29.83 years (+/- 9.44 years)) and three testers participated in two separate experiments. Intra Class Correlation Coefficients (ICCs) and coefficients of variation were used to describe the reliability of two different protocols for positioning subjects on the footplates of the BPM.

RESULTS

Measurements of weight distribution showed high and significant inter- and intra-tester reliability for both protocols (ICCs ranging from 0.720 to 0.868). Sway measurements showed more limited reliability (ICCs ranging from 0.183 to 0.775). Coefficients of variation were low for weight distribution measurements and high for sway measurements.

CONCLUSIONS

Taking the mean of three measurements is recommended for both the weight distribution and the sway measurements as it has shown to produce acceptable measurement results.

Footedness is a better predictor than is handedness of emotional lateralization

A tremendous amount of experimental work has attempted to identify reliable behavioural predictors of cerebral lateralization. Preferred handedness has been the most popular predictor, but some recent reports suggest that preferred footedness may serve as a more accurate predictor of functional laterality, especially in the left-handed population. The present study sought to test this claim by selectively recruiting individuals with either 'crossed' lateral preferences (right-handed and left-footed or left-handed and right-footed) or 'uncrossed' lateral preferences (right-handed and right-footed or left-handed and left-footed). Lateralization of emotional perception was assessed with two blocks of the dichotic Emotional Words Test (EWT), and lateral preference for both handedness and footedness was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred foot (P=0.003), but not with preferred hand. Cerebral lateralization may be more related to footedness than to other lateral preferences.

Lower-limb speed and foot preference in children

Foot preference and performance characteristics of gross-motor lower-limb speed of tapping were examined in 606 4- to 6-yr.-olds. Analysis indicated no effect for gender; however, speed of foot tapping increased significantly across the three ages, suggesting an association with selected developmental (neuromuscular) processes. Contrary to earlier reports on handedness, there was no statistical evidence that mixed- or left-footers were at a performance disadvantage compared to right-footers. All groups performed best with the right foot, limb differentiation (right versus left) being significant for the right- and mixed-footed groups. Speculation about maturational and environmental influences is given.

Patterns of limb laterality and gross-motor agility in children

This study examined the association of nine patterns of limb preference (combination hand/foot), described as congruent or cross-lateral, with gross-motor agility of 302 4- to 6-yr-old boys. Based on contemporary reports of handedness and motor coordination, it was hypothesized that persons exhibiting a right-hand/foot congruent pattern would outperform their peers in other groups. However, analyses indicated no significant differences on total motor performance between groups with different limb patterns. Further nonsupport of the hypothesis was evident since the best performance was exhibited by the mixed-hand/left-foot group. In view of past studies and these results, it appears that additional inquiry is warranted before any consensus regarding the association between limb laterality and motor coordination can be established.

Patterns of Limb Laterality and Gross-Motor Agility in Children

This study examined the association of nine patterns of limb preference (combination hand/foot), described as congruent or cross-lateral, with gross-motor agility of 302 4- to 6-yr.-old boys. Based on contemporary reports of handedness and motor coordination, it was hypothesized that persons exhibiting a right-hand/foot congruent pattern would outperform their peers in other groups. However, analyses indicated no significant differences on total motor performance between groups with different limb patterns. Further nonsupport of the hypothesis was evident since the best performance was exhibited by the mixed-hand/left-foot group. In view of past studies and these results, it appears that additional inquiry is warranted before any consensus regarding the association between limb laterality and motor coordination can be established.

Foot performance of right- and left-handers: a question of environmental influence

Prior research has shown that right-handed adults perform better on a speed-tapping task with the right hand and right foot, while left-handers execute more rapidly with the left hand and right foot. Speculation is that environmental influence, most likely driving experience, may account for the right-foot bias. To examine this hypothesis further, 48 young right- and left-handed children were tested on a similar protocol. Analyses indicated no significant differences in foot performance within hand-preference groups. Since these findings do not complement reports for adults, factors such as experience or maturation might contribute to the difference. Were patterns similar, the effect of environmental influence would be assumed to be small. However, much more evidence is needed before an adequate explanation can be developed. The issue of possible environmental influence is discussed from various theoretical perspectives.

Foot-tapping speed in children ages 4 to 6 years

This investigation examined the performance and measurement characteristics of foot-tapping speed in 155 4- to 6-year-olds. Analysis suggested that, while the task does not differentiate between preferred and nonpreferred limbs, performance does appear to be age-related, that is, subjects tapped significantly faster with increasing age. Considering type of task and population, reliability was judged as moderate.

Associations between hand and foot preference in 3- to 5-year-olds

Associations between foot and hand preference behavior were examined in 3-, 4-, and 5-year-olds. Analysis of the general trichotomous (right, left, mixed) distribution of preferences indicated no sex or age group differences, while noting that 39% were mixed-footed compared to 17% not favoring one hand over the other. Frequency of paired (congruent and cross-lateral) preferences revealed that two patterns, Right-hand/Right-foot (52%) and Right-hand/Mixed-foot (23%) accounted for the vast majority (75%) of subjects. Of the total number of right-handers, most (67%) preferred the right foot, while only 19% of the left-handers were congruent. Thus, supporting findings reported on older populations that right-handers are more consistently right-footed, than left-handers are left-footed. Behavior of the mixed- and right-handed sample was similar, suggesting an overall predominance of these lateral characteristics in young children.

Degree of asymmetry in lateral preferences: eye, foot, ear

Lateral asymmetry in eye, foot, and ear preference was measured using a 15-item questionnaire administered to 442 subjects. Degree and magnitude of asymmetry were greatest for eye, followed by foot and ear. Intercorrelations of lateral preferences were all positive and significant. Two primary factors, eyedness and earedness, were established.

Neuropsychological identification of motor problems: can we learn something from the feet and legs that hands and arms will not tell us?

The degree of structural and functional specialization that differentiates between upper and lower limb use in humans is quite unparalleled among primates. It is argued that less neural resources are devoted to leg and foot control than to arm and hand control, and that this aspect of lower limb innervation, together with the uniquely restricted use of the lower limb, renders lower limb function more sensitive to general neural insult. In addition, the status of leg and foot control differs from that of arm and hand control both early in life and during the later years of decline.