Foot Preference Changes Through Adulthood

Significant gender-specific difference in brain lateralization of schizophrenia patients assessed by new combined foot dominance scale

Objective

Reduced hemispheric asymmetry has been identified as a potential risk factor for schizophrenia, characterized by diminished brain lateralization and a lack of dominance in the left hemisphere. Moreover, there is growing evidence of disrupted connectivity between various cortical regions. This study aimed to investigate gender differences in left-footedness as a potential biological marker for neuronal dysontogenesis in individuals with schizophrenia and control subjects.

Materials and methods

A New Combined Foot Dominance Scale (14 foot tests), comprising a Modified Chapman & Chapman Subscale (10 foot tests) and a Complex Tasks Subscale (four foot tests) was administered as performance tasks in 180 subjects [98 schizophrenia patients with mean age 34.45 years (SD = 15.67, range 23-79) for men and 42.20 years (SD = 11.38, range 21-63) for women and 82 controls with a mean age 34.70 years (SD = 16,82, range 18-79) for men and 44.50 years (SD = 10.73, range 23-67)]. As our data are not continuous and lacks normal distribution, the non-parametric Mann-Whitney test was used for comparing categorical data.

Results

The mean left-footedness, as assessed by the New Combined Foot Dominance Scale, is significantly higher in individuals with schizophrenia compared to control subjects. Our findings from inter-gender comparisons reveal that female schizophrenia patients exhibit a significantly greater average left-footedness than female control subjects, while in males no such a statistical significant difference is detected.

Conclusion

Left foot dominance is higher in patients with schizophrenia than in control subjects and women contribute significantly more to this difference.

Relationships between footedness and aging on postural control: Evidence from the Yakumo study

ABSTRACTThe effects of footedness and aging on postural maintenance function were examined in this study. Using the postural maintenance task, the trajectories of the centre of pressure (COP) were measured with a stabilometer in the lateral and posterior/anterior directions. One hundred and ninety-three right-footers (112 middle-aged: 40-64 years old and 81 old-aged: 65-80 years old) and thirty-two left-footers (14 middle-aged and 18 old-aged) among healthy community members participated in this study. Using the ratio of the COP deviation area sizes for the open- vs. closed-eye conditions as an index, the ratios in the lateral and the posterior/anterior directions were compared in relation to the footedness and the age groups. The results indicated that the left-footers of the older adults group showed a larger COP deviation ratio than that of the middle-aged group, and the left-footers showed a larger deviation ratio in the lateral direction than in the posterior-anterior direction. These findings suggest a weak postural maintenance function of the older adults left footers. As most left-footers are left-handed, health promotion staff should notice that older adults who are left-handers are at a higher risk of falling.

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.

Footedness related differences in femoral bone mineral density in elderly women with osteoporosis

Purpose: The presumed link between lateralized habitual motor activity and bilateral skeletal asymmetry, as result of bone functional adaptation, is the basis for inferences about bone mineral distribution; consequently, bone loss and osteoporosis. As there is no research connecting directly footedness with osteoporosis, the present study was designed to investigate their relation, in elderly women with osteoporosis.Methods: A sample of 420 white, Caucasian race women, older than 65 years, with previous diagnosis of osteoporosis, was recruited for the study. Finally, 164 women met the inclusion criteria and participated. The femoral neck and total hip bone mineral density (BMD) differences between right and left hips of 105 right-footed and 59 non-right-footed women, and the between footedness groups differences of the above right-left BMD differences, were measured with Dual-energy X-ray Absorptiometry (DXA).Results: In right-footers, total hip right-left BMD differences were statistically significant, favoring left femur [t(104) = -2.79, p < .01, two tailed]. In non-right-footers, femoral neck right-left BMD differences were statistically significant, favoring right femur [t(58) =2.025, p < .05, two tailed]. Femoral neck and total hip right-left BMD differences of right- versus non-right-footed women were statistically insignificant.Conclusion: The dominance of the right lower limb had an asymmetric effect on left total hip BMD, while non-right-footedness favored right femoral neck BMD. The findings highlighted the influence of load bearing effects of the body weight and muscle contractions on femoral BMD. We noted a possible association between footedness and BMD, as a result of bone functional adaptation.

Foot preference across the lifespan: Effects of target location and task complexity

This study was designed to determine the factor(s) that influence the choice of the foot throughout the lifespan. To achieve this purpose, 86 right-footed participants (young children (5– 8), adolescents (10–14), young adults (18–25) and older adults (over 50) were tested on two tasks of different levels of difficulty, performed in three spatial locations (left, right, and midline) according to two levels of body posture: sitting and standing. Results revealed that the participants favored their preferred foot when the object was located in the ipsilateral hemispace and at the midline. They selected their non-preferred foot when the object was located in the contralateral hemispace. The participants used their preferred foot to a greater extent during the most complex task than during the easiest one and more often while standing rather than sitting. Finally, we have found a significant age effect. Young children often used the preferred foot more frequently than the other age groups. In conclusion, the findings of this study suggest that foot selection depends on task demand, environmental constraints, and a biological factor associated with motor dominance.

Hand and foot preference in two cultures

Adult participants from India and France were requested to respond to hand and foot preference questionnaires. The items of the questionnaires assessed the choice of the preferred hand and foot on a scale that ranged from extreme left preference through no preference to extreme right preference. Results showed that both groups were more right lateralized for hand actions, whereas foot preferences were less right lateralized and spread across extreme right preference to no preference on the laterality index continuum for men and women. As compared to requiring large numbers for consistency in hand preferences across geographical regions, trends in the lateralization of hand and foot preferences may be consistently obtained with smaller samples. The study reveals the existing difference in lateral preferences between the upper and lower limbs that is sustained regardless of culture or geographical location and indicates the need for further investigation to know why the lower limbs are less lateralized than the upper limbs.

Three-dimensional analysis of shape variations and symmetry of the fibula, tibia, calcaneus and talus

The bones forming the talocrural joint (TCJ) and subtalar joint (STJ) are often assumed to be bilaterally symmetric. Therefore, the contralateral limb (i.e. the fibula, tibia, calcaneus and talus) is used as a template or an intra‐subject control in clinical and research practice. However, the validity of the symmetry assumption is controversial, because insufficient information is available on the shape variations and bilateral (a)symmetry of the fibula, tibia, calcaneus and talus. Using three‐dimensional spatially dense sampled representations of bone shapes extracted from bilateral computed tomography scans of 66 individuals (55 male, mean age: 61 ± 10 years; 11 female, mean age: 53 ± 15 years), we analyzed whether: (i) similar shape patterns exist in the left and right bones of the same type; (ii) gender has an effect on bone shape variations; (iii) intra‐subject shape variation is smaller than that of inter‐subject for a given shape variance direction. For the first set of analyses, all left and right instances of the same type of bone were considered as two separate groups, and statistically compared with each other on multiple aspects including group location (central tendency), variance‐covariance scale (dispersion) and orientation (covariance structure) using distance‐based permutational tests. For the second and third sets of analyses, all left and right bones of the same type were pooled into one group, and shape variations in the TCJ and STJ bones were extracted using principal component analysis. The effects of gender on age‐adjusted bone shape differences were assessed using an analysis of covariance. Moreover, intra‐class correlation was employed to evaluate intra‐ and inter‐subject bone shape variations. For each bone type, both sides had similar shape patterns (P_{permutational}‐values > 0.05). After Bonferroni adjustment, gender led to shape differences, which were mainly in the lateral and medial condyles of the tibia (P = 0.003), the length and height of the calcaneus (P < 0.001), the posterior and anterior talar articular surfaces of the calcaneus (P = 0.001), and in the posterior aspect of the talus (P = 0.001). Intra‐subject shape variations in the tibial tuberosity together with the diameter of the tibia, and the curvature of the fibula shaft and the diameter of the fibula were as high as those of inter‐subject. This result suggests that the shape symmetry assumption could be violated for some specific shape variations in the fibula and tibia.

Joint assessment of handedness and footedness through latent class factor analysis

Recently, some studies have demonstrated the effectiveness of two latent variable approaches in which hand preferences are analysed using either latent class methods or latent class factor (LCF) methods. The main aims of this study are: (i) to establish whether these approaches are adequate for assessing footedness, (ii) to evaluate their appropriateness when hand and foot preferences are jointly analysed, and (iii) to measure the association between handedness and footedness based on the examined latent variable models. To this end, a dataset providing information about the limb used to perform ten hand actions and three foot movements by 2236 young Italian sportspeople is analysed. The first aim is pursued through an exploratory analysis of the observed foot preferences; according to this analysis, footedness patterns are adequately described by two latent levels of footedness. As far as the second aim is concerned, a confirmatory analysis of foot and hand preferences is carried out; the best fit to the dataset is obtained using a two-dimensional LCF model with four latent levels of handedness and two latent levels of footedness. Finally, the association between handedness and footedness resulting from the employed methods is remarkably lower than that registered in other studies.

Could be the predominantly-used hemibody related to the weight bearing distribution modified by the chronic hemiparesis after stroke?

Since the first Broca publications issued from 1970s, lateralized functions in the human brain have urged the researchers to postulate hypothesis based in the right-left asymmetries and, according to some theories, the lateralization of the voluntary motor control could represent a solution to avoid redundant process optimizing space and time. Supported by this idea, the clinicians and researchers tend to concept that the chronic hemiplegic stroke patients learn to use predominantly the non-affected hemibody after stroke in which is more convenient to execute their daily life activities, modifying their natural preference in some cases. Although could seems reasonable conceptualize the non-affected side as the predominantly-used hemibody for motor tasks after stroke (convenience hypothesis), evidences point to exist also hemiplegic patients that developed a predominantly use of the affected side. To float an idea, in terms of weight bearing distribution during upright position, the researchers have found patients overloading the non-affected hemibody, as expected; but also patients overloading the affected hemibody, not presenting necessarily Pusher's syndrome cases. Given the evidences, we could propose a severity-modulated predominance hypothesis which complements the convenience hypothesis. According to our complementary hypothesis, the severity of the motor disability presented in the hemiparesis condition (light, moderate and heavy severity) could determine a predominant use defined by preference (light to moderate severity) or convenience (moderate to heavy severity). In this hypothesis, we postulate ideas from a rehabilitation perspective to be incorporated in treatment programs.

Reference values and psychometric properties of the lower extremity motor coordination test

OBJECTIVES

(1) To create predictive nomograms for the dominant and nondominant limbs on the Lower Extremity Motor Coordination Test (LEMOCOT) using reference values, and (2) to determine the inter- and intrarater reliability for the LEMOCOT; the best scoring method (first vs mean of the first 2 vs mean of the last 2 vs mean of 3 vs the highest of 3 trials); the best testing method (direct vs video observation); and the ability to detect real change (smallest real difference [SRD] and standard error of the measurement [SEM]).

DESIGN

Normative and methodological study.

SETTING

Metropolitan area.

PARTICIPANTS

Healthy individuals (N=320, 50% women) in 7 age groups: 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 69, 70 to 79, and ≥80 years. Each group had 50 participants, except for ≥80 years (n=20).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE LEMOCOT RESULTS

Age and sex explained 48% of the variance in the LEMOCOT scores for the dominant limb and 44% for the nondominant limb (125<F<148; P<.001). No significant differences were found regarding the different scoring methods (.12<F<1.02; .10<P<.92), and all of them demonstrated good reliability (intraclass correlation coefficients between .90 and .99; P<.001). There was agreement between scores from direct and video observation (limits of agreement -1.99 to 1.85; -1.55 to 1.62). Appropriate SEM (2.27-1.85) and SRD (6.27-5.11) values were found.

CONCLUSIONS

Reference values were determined for the LEMOCOT, and predictive nomograms were created based on age and sex. The LEMOCOT is reliable, needing only 1 trial (after familiarization) to generate reliable scores; can be scored from either direct or video observation; and has the ability to detect real change over time.

Femoral neck-shaft angle in humans: variation relating to climate, clothing, lifestyle, sex, age and side

The femoral neck-shaft angle (NSA) varies among modern humans but measurement problems and sampling limitations have precluded the identification of factors contributing to its variation at the population level. Potential sources of variation include sex, age, side (left or right), regional differences in body shape due to climatic adaptation, and the effects of habitual activity patterns (e.g. mobile and sedentary lifestyles and foraging, agricultural, and urban economies). In this study we addressed these issues, using consistent methods to assemble a global NSA database comprising over 8000 femora representing 100 human groups. Results from the analyses show an average NSA for modern humans of 127° (markedly lower than the accepted value of 135°); there is no sex difference, no age-related change in adults, but possibly a small lateral difference which could be due to right leg dominance. Climatic trends consistent with principles based on Bergmann's rule are evident at the global and continental levels, with the NSA varying in relation to other body shape indices: median NSA, for instance, is higher in warmer regions, notably in the Pacific (130°), whereas lower values (associated with a more stocky body build) are found in regions where ancestral populations were exposed to colder conditions, in Europe (126°) and the Americas (125°). There is a modest trend towards increasing NSA with the economic transitions from forager to agricultural and urban lifestyles and, to a lesser extent, from a mobile to a sedentary existence. However, the main trend associated with these transitions is a progressive narrowing in the range of variation in the NSA, which may be attributable to thermal insulation provided by improved cultural buffering from climate, particularly clothing.

A valid and reliable clinical determination of footedness

OBJECTIVE

To develop a valid and reliable clinical performance measure of foot dominance.

DESIGN

Prospective cross-sectional study with repeated measures.

SETTING

Laboratory.

PARTICIPANTS

A total of 175 healthy male and female subjects ages 16 to 37 years.

INTERVENTIONS

A total of 12 lower limb functional performance skilled and unskilled tasks.

MAIN OUTCOME MEASURE

Internal consistency and reliability of selected measures.

RESULTS

Principal components factor analysis with varimax rotation resulted in tasks being grouped into 3 components with Eigen values greater than 1, which explained 55% of the variance. An inventory of 4 skilled component tasks was found to reliably determine footedness. Internal consistency derived from Cronbach's alpha produced a value of 0.819 for the skilled tasks. Three of the 4 skilled tasks were found to have excellent reliability (>0.75) with almost perfect agreement.

CONCLUSIONS

Determining foot dominance is important in a rehabilitation setting, considering the normal laterality variation in cerebral hemisphere function, limb morphology, and motor performance parameters encountered in humans. This study developed an inventory of skilled performance tasks to reliably determine footedness. Four bilateral tasks were identified that had excellent test-retest reliability and high internal consistency and are recommended as global determinants of footedness.

RELATIONSHIPS BETWEEN HAND AND FOOT PREFERENCES

The aim of this study was to evaluate the relations between hand and foot preferences in male and female individuals (343 male, 290 female) aged between 18-42 years (22.11 +/- 2.07). Of the right-handed men, 75.5% preferred the right foot, 7.1% the left foot, and 17.4% both feet. Of ambidextrous men, 44.0% preferred the right foot, 28.0% the left foot, and 28.0% both feet. Of left-handed men, 32.3% preferred the right foot, 56.9% the left foot, and 10.8% both feet. The differences between these percentages were found to be statistically significant. Of the right-handed women, 89.9% preferred the right foot, left foot 1.2%, both feet 8.9%, whereas 50.0% preferred the right foot, 12.5% the left foot, and 37.5% both feet in the ambidextrous women. In the left-handed women, 8.8% preferred the right foot, 79.4% the left foot, and 11.8% both feet. The differences between these percentages were found to be statistically significant. The results suggested that the cultural differences among the difference study groups may be the reason for the inconsistencies with regard to hand and foot preferences. Moreover, the results may bring insight into the foot preference in relation to hand preference in the Turkish population.

Visual guidance of the human foot during a step

When the intended foot placement changes during a step, either due to an obstacle appearing in our path or the sudden shift of a target, visual input can rapidly alter foot trajectory. However, previous studies suggest that when intended foot placement does not change, the path of the foot is fixed after it leaves the floor and vision has no further influence. Here we ask whether visual feedback can be used to improve the accuracy of foot placement during a normal, unperturbed step. To investigate this we measured foot trajectory when subjects made accurate steps, at fast and slow speeds, to stationary floor-mounted targets. Vision was randomly occluded in 50% of trials at the point of foot-off. This caused an increase in foot placement error, reflecting lower accuracy and higher variability. This effect was greatest for slow steps. Trajectory heading analysis revealed that visually guided corrections occurred as the foot neared the target (on average 64 mm away). They occurred closer to the target for the faster movements thus allowing less time and space to execute corrections. However, allowing for a fixed reaction time of 120 ms, movement errors were detected when the foot was approximately halfway to the target. These results suggest that visual information can be used to adjust foot trajectory during the swing phase of a step when stepping onto a stationary target, even for fast movements. Such fine control would be advantageous when environmental constraints place limitations on foot placement, for example when hiking over rough terrain.

Footedness across the age span among Brazilian right- and left-handers

Previous cross-sectional surveys have reported a decreasing prevalence of left-footedness with increasing age. Bell and Gabbard attributed this pattern to a developmental process wherein the right hemisphere ages earlier than the left, leading to a decline in left-footedness among older individuals. A major flaw in this hypothesis is that age-related data were derived exclusively from right-handed samples. To test the generality of the hypothesis we obtained foot preferences from 1462 right and 172 left-handed Brazilians ranging from 10 to 94 years of age. In only one of the three analyses did dextrals show the predicted age-related decline. Together with accelerating trends towards left-footedness among older males and nonlinear trends among left-handers as a group, these results do not sustain the basic assumptions implicit in the right hemisphere aging hypothesis.