Manual Asymmetries Research Articles

Skeletal facial asymmetry: reliability of manual and artificial intelligence-driven analysis.

To compare artificial intelligence (AI)-driven web-based platform and manual measurements for analysing facial asymmetry in craniofacial CT examinations. The study included 95 craniofacial CT scans from patients aged 18-30 years. The degree of asymmetry was measured based on AI platform-predefined anatomical landmarks: sella (S), condylion (Co), anterior nasal spine (ANS), and menton (Me). The concordance between the results of automatic asymmetry reports and manual linear 3D measurements was calculated. The asymmetry rate (AR) indicator was determined for both automatic and manual measurements, and the concordance between them was calculated. The repeatability of manual measurements in 20 randomly selected subjects was assessed. The concordance of measurements of quantitative variables was assessed with interclass correlation coefficient (ICC) according to the Shrout and Fleiss classification. Erroneous AI tracings were found in 16.8% of cases, reducing the analysed cases to 79. The agreement between automatic and manual asymmetry measurements was very low (ICC < 0.3). A lack of agreement between AI and manual AR analysis (ICC type 3 = 0) was found. The repeatability of manual measurements and AR calculations showed excellent correlation (ICC type 2 > 0.947). The results indicate that the rate of tracing errors and lack of agreement with manual AR analysis make it impossible to use the tested AI platform to assess the degree of facial asymmetry.

Psychophysiological Characteristics of Athletes-Volleyball Players with Hearing Impairment

To reveal the features of the central nervous system and the severity of hemispheric asymmetry in volleyball athletes with hearing deprivation. Materials and methods: The study involved 14 athletes with hearing deprivation of varying degrees, aged 20 to 35 years (mean age 29.20 ± 1.3 years), with different sports qualifications. When evaluating the indicators of a simple visual-motor reaction, the reaction time, the degree of its stability, the level of functional capabilities of the nervous system of athletes were determined. To determine manual asymmetry, M. Annette's questionnaire, motor tests (dynamometry, tests for the interlacing of hands and applause) were used, and the coefficient of the right hand was calculated. When detecting visual asymmetry, the Rosenbach test and the spyglass test were used. The ratio of the right eye was also calculated. Results: It was revealed that a third of the examined athletes have a symmetrical distribution of signs both in the visual and manual spheres, a significant dependence of which on sports titles was not found. The time of a simple visual-motor reaction in volleyball athletes with hearing deprivation was reduced. The stability of the reaction and the level of functional capabilities were within the normal range and had a significant dependence on the sports title and category. Conclusion: It was revealed that volleyball players with hearing impair ment form a special type of interhemispheric interaction, characterized by a more even distribution of functional activity between the right and left hemispheres, and in connection with this, a low level of development of manual and visual asymmetry.

Aging reduces manual dexterity and force production asymmetries between the hands

ABSTRACT Age-related effects on motor asymmetry provide insight into changes in cortical activation during aging. To investigate potential changes in manual performance associated with aging, we conducted the Jamar hand function test and the Purdue Pegboard test on young and older adults. All tests indicated reduced motor asymmetry in the older group. Further analysis suggested that a significant decline in dominant (right) hand function resulted in less asymmetric performance in older adults. The finding is inconsistent with the application of the HAROLD model in the motor domain, which assumes improved performance in the non-dominant hand, leading to a reduction of motor asymmetry in older adults. Based on the manual performance in young and older adults, it is suggested that aging reduces manual asymmetry in both force production and manual dexterity due to the reduced performance of the dominant hand.

Reduction in manual asymmetry and decline in fine manual dexterity in right-handed older adults with mild cognitive impairment

ABSTRACT Research in Parkinson’s or Alzheimer’s disease suggests that hand function is affected by neurodegenerative diseases. However, little is known about the relationship between hand function and mild cognitive impairment (MCI). Therefore, we conducted a kinematic analysis of unimanual hand movements in MCI patients to answer whether manual asymmetries and manual dexterity are affected or preserved in this condition. Forty-one MCI patients and fifty healthy controls were tested with the Purdue Pegboard test. All participants were right-handed. Kinematic analyses (by hand) were calculated for path length, angle, and linear and angular velocities during reaching, grasping, transport and inserting. Group differences were tested by with factorial MANOVAs and laterality indexes (LI) were assessed. Groups were compared on “Right–Left” hand correlations to identify kinematics that best single-out patients. Kinematics from grasping and inserting were significantly more deteriorated in the MCI group, while outcomes for reaching and transport denoted superior performance. LIs data showed symmetry of movements in the MCI group, during reaching and transport. Comparisons of “Right–Left” hand correlations revealed that kinematics in reaching and transport were more symmetrical in patients. This study showed a deterioration of fine manual dexterity, an enhancement in gross dexterity of upper-limbs, and symmetrical movements in MCI patients.

Reaching versus catching: flexible hand preference in ring-tailed lemurs

Compared to other primate taxa, hand preference in strepsirrhines has been poorly investigated and the available studies have often produced conflicting results. Thanks to their remarkable plasticity in foraging and postural habits, ring-tailed lemurs (Lemur catta) represent a key model species to examine manual lateralisation. We video-recorded 23 individuals hosted at four Italian zoological gardens during three food-related trials requiring different kinds of manual actions. We found a remarkable hand preference at individual level for grasping static food presented in a bowl, both when only one kind of food was offered (“food limited-choice” task) and when a mix of less and more palatable food items were available (“food large-choice” task). Conversely, most individuals did not show any hand preference for catching highly palatable food in motion (“catching” task). Moreover, the subjects not showing any hand preference engaged more frequently in bimanual actions (concurrent and symmetric use of both hands in catching food) than the subjects displaying a manual asymmetry. No detrimental effect on the task performance was recorded, indicating a high level of hand selection plasticity in Lemur catta. In conclusion, our findings show that ring-tailed lemurs can take advantage from a flexible manual strategy and highlight how ecological factors must be carefully evaluated when assessing hand preference in extant strepsirrhines.

A Comparison of the Muscle Activation, Proprioception and Anthropometric Characteristics of the Dominant and Non-dominant Wrists

Purpose: Manual asymmetry refers to tendency that is in favor of hand to perform manual tasks requiring skills, it is important in every sensory and motor function. This study aimed to compare the muscle activation, proprioception, and anthropometric characteristics of the dominant and non-dominant wrists. &#x0D; Methods: In the study, forty young individuals aged between 18-25 years, who volunteered to participate, were included. As anthropometric measurements, the upper extremity length measurement forearm length measurement, hand length measurement wrist diameter measurement, hand width, shape and digit index measurements were performed, respectively. The muscle strength of wrist flexor and extensor muscles was measured by a hand dynamometer, while their muscle activations were measured by electromyography. The arm carrying angle was evaluated by a universal goniometer. &#x0D; Results: The mean age of the individuals included in the study was 22.51 ± 0.35 years. In the right dominant individuals, when the dominant and non-dominant sides were compared, a statistically significant difference was found between flexor muscle activations, muscle strength, and hand width (p0.05). &#x0D; Conclusion: Finding the dominant side's wrist flexor muscle activations, extensor muscle strength, and hand widths better in young individuals showed that the dominant side was frequently used in daily living activities. The difference was seen that the non-dominant side would be weaker and at higher risk of deformity with increasing age and in the presence of any rheumatic, orthopedic, and neurologic diseases.

The influence of hereditary factor upon the development of thinking skills in confluence of the factors of manual asymmetry and hearing impairment

The subject of this research is the peculiarities of development of thinking skills in confluence of the factors of manual asymmetry and hearing impairment in families in which parents have hearing impairment and preserved hearing. The object of this research is the characteristics of thinking in combination of hearing impairment and manual asymmetry. The author dwells on such aspects as hereditary factor in the formation of thinking skills among left-handed and right-handed students with hearing impairment. Special attention is given to the peculiarities of the formation of thinking in combination of hearing impairment and manual asymmetry among students brought up by deaf or normally hearing parents. The main conclusions are as follows: right-handed students with hearing impairment brought up by deaf parents have higher characteristics of logical and creative thinking than students brought up by normally hearing parents; left-handed students from families of the deaf have higher characteristics of creative thinking if their parents' hearing is preserved, while the characteristics of logical thinking are higher if their parents&amp;rsquo; hearing is impaired; a "mirror image" is detected in the development of creative thinking among left-handed and right-handed students, depending on the hearing condition of their parents; connection is established between logical and creative. The author&amp;rsquo;s special contribution lies in acquisition of data on the influence of hereditary factor upon the development of thinking in combination of hearing impairment and manual asymmetry. The novelty of this research consists in comparative study of creative and mathematical thinking in confluence of the factors of hearing impairment, manual asymmetry and a hereditary factor. New data is obtained on the peculiarities of development of thinking skills among right-handed and left-handed students with hearing impairments brought up by hearing parents and parents with hearing impairment.

Modulation of motor cortices on manual asymmetries

Differences between hands in motor performance are associated with differences in the interaction of inhibitory connections of homologous parts of the cerebral hemispheres. Modulation of these inhibitory connections in the right and left primary motor cortex (M1) may alter manual performance asymmetries. To investigate this assumption, eleven right-handed male university students performed a discrete aiming task in a digitizing tablet under three experimental conditions: dominant M1 inhibition, non-dominant M1 inhibition, and sham. The Transcranial Direct Current Stimulation technique was used to increase or decrease participants’ M1 excitability. We used a within-subject design, in which we counterbalanced the order of conditions and the order of the starting hand among participants. The performance-dependent variables were: reaction time, movement time, and radial error, while kinematic variables were: peak velocity, relative time to peak velocity, and number of discontinuities in acceleration in the final homing phase. Results showed changes in asymmetry related to reaction time, movement time, and relative time to peak velocity. The interaction between M1 modulation and hemispheric specialization produced specific changes in these variables. Taken together, these findings revealed that modulation of the dominant and non-dominant M1 affects manual performance asymmetries.

Age-related Reductions in Manual Asymmetry with Increased Visuospatial Demands

Age-related Reductions in Manual Asymmetry with Increased Visuospatial Demands

Manual Asymmetry of the Relationship Between Velocity and Accuracy on Reciprocal Hand Movements Under the Viscous Force Fields

Manual Asymmetry of the Relationship Between Velocity and Accuracy on Reciprocal Hand Movements Under the Viscous Force Fields

PSYCHOPHYSIOLOGICAL FEATURES OF VOLLEYBALL PLAYERS WITH HEARING IMPAIRMENT

Aim. The paper aims to reveal the features of the central nervous system and interhemispheric asymmetry in volleyball players with hearing impairment. Materials and methods. The study involved 14 athletes of various sports experience with varying degrees of hearing impairment aged from 20 to 35 years (average age 29.20 ± 1.3 years). Simple visual reaction was studied in terms of the reaction time, reaction stability, and functional capabilities of the nervous system. To establish the manual asymmetry, the M. Annette questionnaire and motor tests (dynamometry, tests for intertwined fingers, the applause test) were used, the coefficient of the right hand was calculated. When detecting visual asymmetry, the Rosenbach test and the telescope test were used. The coefficient of the right eye was also calculated. Results. It was established that a third of the examined athletes had a symmetric distribution of signs in both the visual and manual spheres. The reliable dependence between symmetric distribution and sports titles was not found. The reaction time in volleyball players with hearing impairment was reduced. The reaction stability and the level of functional capabilities were within the normal range and had a significant dependence on the sports rank and category. Conclusion. It was revealed that volleyball players with hearing impairment formed a special type of interhemispheric interaction characterized by a more uniform distribution between the right and left hemispheres, which resulted in low values of manual and visual asymmetry.

Movement Kinematics and Interjoint Coordination Are Influenced by Target Location and Arm in 6-Year-Old Children.

Rapid aiming movements are typically used to study upper limb motor control and development. Despite the large corpus of work in this area, few studies have examined kinematic manual asymmetries in children who have just started formal schooling and until now, none have characterized how children coordinate their joints to complete these movements (i.e., interjoint coordination). In the present study, manual asymmetries in kinematics and interjoint coordination in strongly right-handed 6-year-old children were investigated when reaching for ipsilateral and contralateral targets with their dominant right arm and the non-dominant left arm. Overall, manual asymmetries in interjoint coordination are apparent for both 6-year-old children and young adults, although young children completed the task by adopting a different strategy than adults. Also, control strategies employed by 6-year-old children were influenced by both the location of the target as well as the arm used to perform the task. Specifically, compared to all other conditions, children’s trajectories were more curved when performing contralateral movements with the non-dominant left arm, which were driven by smaller shoulder excursions combined with larger elbow excursions for this condition. Based on these results, we argue that the differences in interjoint coordination reflect the stage of development of 6-year-old children, the origin of which derives from maturational (e.g., hand dominance) and environmental factors (e.g., school-based experience).

Neurophysiological basis of manual force asymmetries in young and senior adults

ABSTRACT In this study, we investigated age differences in manual force production to explore their neurophysiological basis. Manual pinching and gripping forces were first measured during unilateral and bilateral efforts in two groups of right-handed adults (young, n = 12, senior, n = 11). Then, transcranial magnetic stimulation (TMS) was applied to each hemisphere to assess central motor inhibition via the contralateral and ipsilateral silent period (cSP, iSP). Laterality quotients (LQs) were computed to determine asymmetries for unimanual strength tests and hemispheric asymmetries in TMS measures. Bilateral indices (BLI) were computed to assess the bilateral force deficit (BFD). During unilateral efforts, both young and senior participants exhibited similar degrees of asymmetry. Similarly, no age difference was detected when comparing LQs derived from TMS measures. During bilateral efforts, although BLI tended to be lower in seniors, no age difference was detected. Asymmetry in strength and BLI showed no association with hemispheric asymmetry in TMS measures, except for the asymmetry in pinch strength, which was associated with asymmetry in the iSP duration. These observations confirm that asymmetries in manual strength and BFD are little affected by age. Also, our results show that hemispheric asymmetries in transcallosal inhibition are associated with pinch strength asymmetry.

ЕМГ – активність м’язів верхньої кінцівки людини при патології нервово-м’язового проведення

In many cases of a disease or an injury of the upper extremity nerve impulses are impaired. The high level of diagnostic and tactical errors in upper limb's nerve damage often leads to poor treatment outcomes. An important, and sometimes decisive, factor in the choice of treatment is the assessment of the functional state of the nerves and muscles of the affected limb segment. The purpose of this testing is to study the features of the upper limb muscles's EMG activity in normal and in the case of clinical pathology of neuromuscular transmission.&#x0D; 24 volunteers between the ages of 17 and 32, both male and female, with the right profile of manual asymmetry took part in the study. While dividing into groups, the presence of the diagnosted pathology of the upper right limb's neuromuscular transmission was taken into account. Accordingly, we created a "pathological" (n = 8) and "healthy" (n = 16) groups. In both groups, we sequentially recorded the M-response of the abductor pollicis brevis during stimulation of the nerve medianus as well as the M-response of the abductor digiti minimi during stimulation of the nerve ulnaris. The M-response amplitude, residual latency (RL), and excitation propagation rate (EPR) were analyzed.&#x0D; It has been established that the amplitudes of the M-responce during EMG stimulation of the abductor pollicis brevis and the abductor digiti minimi were lower in pathological group than tin normal. According to our results, RL of examined muscles' M-response increased with distanting away from the stimulation point (muscle's working point). In the case of pathology we observed longer RL of M-responce than in healthy testees. In the case of stimulation of the abductor pollicis brevis EPR was comparely higher on the elbow-shoulder segment and the wrist-shoulder segment in the pathological group, wereas while stimulation of the abductor digiti minimi we established inverse relationship. EPR in all segments, namely the wrist-shoulder and elbow-shoulder, was lower in the pathologic group compared to the norm.

Association Between the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism and Manual Performance Asymmetries.

Within the cognitive domain, neuroscience and cognitive psychology researchers have investigated the relationship between handedness and cognitive skills. However, there have been few studies of the three-way association between manual asymmetry, its genetic components, and cognition even though this line of research could further an understanding of asymmetry. One enzyme involved in cognitive functions related to the dopaminergic system and to the prefrontal cortex is the catechol-O-methyltransferase (COMT), and it has a trimodal activity distribution in the human population due to its functional polymorphism known as Val158Met. This study investigated whether this COMT polymorphism is associated with asymmetries in the performance of a manual dexterity task. Forty-two right-handed undergraduate students ( Mage = 25.12, SD = 5.84; 15 women, 27 men) performed two trials each of place and remove conditions of the Grooved Pegboard Test with each hand (right and left), counterbalancing the order of the initial or starting hand. We calculated the mean time to perform the task for both hands on both trials and found, as hypothesized, that the Met/Met group gave a more asymmetrical performance than the Val/Met group under the place condition because dopamine levels reduced flexible behavior for the Val/Met group. We suspect that the place condition requires greater interhemispheric connectivity, as it requires a greater cognitive flexibility, and highly asymmetrical individuals are said to be less flexible. The findings of this study suggest a significant association between the COMT polymorphism and manual asymmetry in healthy populations.

History, development and current advances concerning the evolutionary roots of human right‐handedness and language: Brain lateralisation and manual laterality in non‐human primates

AbstractThis review highlights the scientific advances concerning the origins of human right‐handedness and language (speech and gestures). The comparative approach we adopted provides evidence that research on human and non‐human animals’ behavioural asymmetries helps understand the processes that lead to the strong human left‐hemisphere specialisation. We review four major non‐mutually exclusive environmental factors that are likely to have shaped the evolution of human and non‐human primates’ manual asymmetry: socioecological lifestyle, postural characteristics, task‐level complexity and tool use. We hypothesise the following scenario for the evolutionary origins of human right‐handedness: the right‐direction of modern humans’ manual laterality would have emerged from our ecological (terrestrial) and social (multilevel system) lifestyle; then, it would have been strengthened by the gradual adoption of the bipedal stance associated with bipedal locomotion, and the increasing level of complexity of our daily tasks including bimanual coordinated actions and tool use. Although hemispheric functional lateralisation has been shaped through evolution, reports indicate that many factors and their mutual intertwinement can modulate human and non‐human primates’ manual laterality throughout their life cycle: genetic and environmental factors, mainly individual sociodemographic characteristics (e.g., age, sex and rank), behavioural characteristics (e.g., gesture per se and gestural sensory modality) and context‐related characteristics (e.g., emotional context and position of target). These environmental (evolutionary and life cycle) factors could also have influenced primates’ manual asymmetry indirectly through epigenetic modifications. All these findings led us to propose the hypothesis of a multicausal origin of human right‐handedness.

The effect of aging and contextual information on manual asymmetry in tool use.

Healthy aging affects manual asymmetries in simple motor tasks, such as unilateral reaching and aiming. The effects of aging on manual asymmetries in the performance of a complex, naturalistic task are unknown, but are relevant for investigating the praxis system. This study examined how aging influences manual asymmetry in different contexts in a tool manipulation task. Fifty healthy, right-hand-dominant young (N = 29; 21.41 ± 2.87years), and elderly (N = 21; mean: 74.14 ± 6.64years) participants performed a 'slicing' gesture in response to a verbal command in two contexts: with (tool) and without the tool (pantomime). For interjoint relationships between shoulder plane of elevation and elbow flexion, a HAND × AGE × CONTEXT interaction existed (F1,43 = 4.746, p = 0.035). In pantomime, interjoint control deviated more in the left (non-dominant) than the right (dominant) limb in the elderly adult group (Wilcoxon, p = 0.010). No such differences existed in the young adult group (Wilcoxon, p = 0.471). Furthermore, contextual information reduced interjoint deviation in young adults when the task was performed with the right (dominant) hand (Wilcoxon, p = 0.001) and in the elderly adults when the task was performed with the left (non-dominant) hand (Wilcoxon, p = 0.012). The presence of the tool did not reduce interjoint deviation for the right hand in the elderly group (Wilcoxon, p = 0.064) or the left hand in the young group (Wilcoxon, p = 0.044). Deviation within trials (i.e., intrasubject deviation) in elbow flexion was higher in the elderly relative to the young adult group (p = 0.003). Finally, resultant peak velocities were smaller (p = 0.002) and cycle duration longer (p < 0.0001) in the elderly adult group. This study provides novel evidence that aging affects manual asymmetries and sensorimotor control in a naturalistic task and warrants that aging research considers the context in which the task is performed.

Manual asymmetry in older adults on a complex coincidence-anticipation task

ABSTRACTAge-related asymmetrical functional decline was tested in a sample of 57 right-handed volunteers between 65 and 85 years of age. Participants performed a complex coincidence-anticipation (CA) task with both preferred and non-preferred hands. Results demonstrated that the proficiency of a complex CA task was similar for the 2 age groups, but different for the 2 hands. The non-preferred hand was more proficient for temporal accuracy but not for response timing, which was similar for both hands. Moreover, the lack of interaction between age and hand both in response timing and response accuracy reveal symmetric performance across ages.

Statistical analysis of manual asymmetry manifestation in the best fencers of the world and Ukraine

The indices of the analysis of manual asymmetry manifestation among the leading fencers of the world and Ukraine are given. The tendency of the increase in the number of left-handed sportsmen in fencing over the past 10 years has been determined: among adult athletes – by 17.3 %, among youth – by 12 %. It is proved that left-handed sportsmen have an advantage over athletes fencing with the right hand, as evidenced by the rating of the International Fencing Federation.

Handedness and Reach-to-Place Kinematics in Adults: Left-Handers Are Not Reversed Right-Handers

ABSTRACTThe primary goal of this study was to examine the relations between limb control and handedness in adults. Participants were categorized as left or right handed for analyses using the Edinburgh Handedness Inventory. Three-dimensional recordings were made of each arm on two reach-to-place tasks: adults reached to a ball and placed it into the opening of a toy (fitting task), or reached to a Cheerio inside a cup, which they placed on a designated mark after each trial (cup task). We hypothesized that limb control and handedness were related, and we predicted that we would observe side differences favoring the dominant limb based on the dynamic dominance hypothesis of motor lateralization. Specifically, we predicted that the dominant limb would be straighter and smoother on both tasks compared with the nondominant limb (i.e., right arm in right-handers and left arm in left-handers). Our results only partially supported these predictions for right-handers, but not for left-handers. When differences between hands were observed, the right hand was favored regardless of handedness group. Our findings suggest that left-handers are not reversed right-handers when compared on interlimb kinematics for reach-to-place tasks, and reaffirm that task selection is critical when evaluating manual asymmetries.