Hand Size Research Articles

An Embodied Approach to Perception

When humans perceive the environment, angular units of visual information must be transformed into units appropriate for the specification of such parameters of surface layout as extent, size, and orientation. Our embodied approach to perception proposes that these scaling units derive from the body. For example, hand size is relevant for scaling the size of a strawberry, whereas an extent across a meadow is scaled by the amount of walking required to traverse it. In his article, Firestone (2013, this issue) argued that our approach is wrong; in fact, he argued that it must be wrong. This reply to Firestone’s critique is organized into three parts, which address the following questions: (a) What is the fundamental question motivating our approach? (b) How does our approach answer this question? (c) How can we address Firestone’s arguments against our approach? A point-by-point critique of Firestone’s arguments is presented. Three conclusions are drawn: (a) Most of Firestone’s arguments reflect a misunderstanding of our approach, (b) none of his arguments are the fatal flaws in our approach that he believes them to be, and (c) there are good reasons to believe that perception—just like any other biological function—is a phenotypic expression.

Feasibility and safety of a novel in vivo model to assess playground falls in children

Falls are the leading cause of nonfatal unintentional injuries among hospitalized children with playground equipment accounting for more than 50%. National standards for playground rung and rail design exist, but there a lack of in vivo models available to test these standards. We developed a novel in vivo model to test rung and rail design. We report the feasibility and safety of the model. A device was built to simulate children hanging onto a playground bar until their hand slips off. This was defined as breakaway strength. The handle unit was mounted on a vertical cable that was mechanically raised and lowered using a linear actuator controlled by the experimenter. The unit was padded and contained a video camera that recorded the posture of the hand during each trial. Breakaway force and torque were recorded as they held onto the handle by LabView software. In addition, standard anthropometrics and grip strength were recorded. Biomedical engineering approved the device. There were 425 eligible students aged 5 years to 11 years. Of these, 93% (397) participated (212 males and 185 females). Ninety-nine percent (396 of 397) completed all three experimental stations, one declined because of fear. There were no injuries and no falls. Average time to complete the study was 22 ± 0.5 minutes. Ninety-one percent of participants were right handed; the ethnicity was representative of the local area with 79% being white. Mean ± SD height, weight, and body mass index for the 397 participants were 1.28 ± 0.11 m, 28.0 ± 8.12 kg, and 16.31 ± 2.59 kg/m², respectively. Hand size, grip strength, and maximum breakaway force increased with age. This model is safe and feasible and maybe a viable method to assess rung and rail design for playgrounds.

The costs and benefits of flexibility as an expression of behavioural plasticity: a primate perspective

Traditional neo-Darwinism ascribes geographical variation in morphology or in behaviour to varying selection on local genotypes. However, mobile and long-lived organisms cannot achieve local adaptation this way, leading to a renewed interest in plasticity. I examined geographical variation in orang-utan subsistence and social behaviour, and found this to be largely owing to behavioural plasticity, here called flexibility, both in the form of flexible individual decisions and of socially transmitted (cultural) innovations. Although comparison with other species is difficult, the extent of such flexibility is almost certainly limited by brain size. It is shown that brains can only increase relative to body size where the cognitive benefits they produce are reliably translated into improved survival rate. This means that organisms that are very small, face many predators, live in highly seasonal environments, or lack opportunities for social learning cannot evolve greater flexibility, and must achieve local adaptation through selection on specific genotypes. On the other hand, as body and brain size increase, local adaptation is increasingly achieved through selection on plasticity. The species involved are also generally those that most need it, being more mobile and longer-lived. Although high plasticity buffers against environmental change, the most flexible organisms face a clear limit because they respond slowly to selection. Thus, paradoxically, the largest-brained animals may actually be vulnerable to the more drastic forms of environmental change, such as those induced by human actions.

Vestibular contributions to bodily awareness

The vestibular system has widespread interactions with multisensory cortical networks, including the somatosensory areas. Several clinical observations suggested that vestibular signals are essential to compute more abstract cognitive representations of the body. However, the existing literature is generally based on isolated reports. We aimed to provide both a theoretical framework, and an experimental method to investigate potential vestibular contributions to somatic cognition. Accordingly, we have investigated effects of galvanic vestibular stimulation (GVS) on the localisation of a stimulus on the skin of the hand (a process that we define as somatoperception) and on the implicit representation of the hand size and shape (involving a different process which we define as somatorepresentation).Vestibular input influenced the localisation of tactile stimuli on the hand: touches on the dorsum of the hand were perceived as shifted toward the wrist. The specific polarity of vestibular stimulation influences the localisation errors. Right anodal and left cathodal, which influences both cerebral hemispheres, induced a stronger localisation bias compared to left anodal and right cathodal GVS, which influences primarily the right hemisphere. Although our data confirmed previous findings that the body model of the shape of the hand is massively distorted, vestibular inputs do not contribute to these distortions.Our results suggest that vestibular input influences the registration of somatosensory input onto a map of the body (somatoperception), but does not influence stored knowledge about the spatial organisation of the body as a physical object (somatorepresentation).

Variation in work tasks in relation to pinch grip strength among middle-aged female dentists

ObjectivesWe aimed to investigate the relationship of task variation during dental work history with pinch grip strength among dentists. MethodsWe measured pinch grip strength among 295 female Finnish dentists aged 45–63 years. Variation in dental work tasks during work history was empirically defined by cluster analysis. Three clusters of task variation emerged: low (most work time in restoration treatment/endodontics), moderate (about 50% in the former and 50% in prosthodontics/periodontics/surgery), and high (variable tasks including administrative duties). Hand radiographs were examined for the presence of OA in the wrist and each joint of the 1–3rd fingers. Information on hand-loading leisure-time activities, and joint pain was obtained by questionnaire. Glove size was used as a proxy for hand size. BMI (kg/m2) was based on measured weight and self-reported height. ResultsDentists with low variation of work task history had an increased risk of low pinch grip strength in the right hand (OR 2.3, 95% CI 1.2–4.3), but not in the left (1.13, 0.62–2.08), compared to dentists with high task variation, independent of age, hand size, hand-loading leisure-time activities, BMI and symptomatic hand OA. ConclusionThe dentists with the most hand-loading tasks were at an increased risk of low pinch grip strength, independent of e.g. symptomatic hand OA. It is advisable among dentists to perform as diverse work tasks as possible to reduce the risk of decreased pinch grip strength.

Medieval Habit, Modern Sensation:

[H]abit is an immensely powerful agent for regulating, even creating, the acuity of sentience. Just as one may regulate the amount of light by opening and closing one’s eyelids or by turning and tilting one’s head through hundreds of angles and planes, so habit acts to set in place countless gateways that either open and allow the world to rush toward one or instead close it to keep it wholly at bay. —elaine scarry1

Exploration of hand size as a screening tool for acromegaly

Exploration of hand size as a screening tool for acromegaly

Oral Poster Abstracts

Background Ventilation during neonatal resuscitation is typically initiated with a face mask, but may be ineffective due to leak or obstruction. Objective To compare leak using three methods of mask hold. Methods Medical and nursing staff regularly involved in neonatal resuscitation used the three holds (twopoint, two-handed, spider) on a manikin in a random order to apply positive pressure ventilation (PPV) at standard settings each for 1 min while mask leak was recorded. Results Participants (n=53) varied in experience (1–23 years) and hand size. Combined median (IQR) leak was 14 (2–46)% and was not different among the holds. Conclusions There was no difference in the leak measured using the three different mask holds.

Reliability and validity of the figure-of-eight method of measuring hand size in patients with breast cancer-related lymphoedema

Breast cancer-related lymphoedema (BCRL) affects 24-42% of patients following treatment for breast cancer. The gold standard method of measuring hand swelling associated with BCRL is to use water displacement (volumeter). This is not always possible in the clinical setting and the figure-of-eight method, which involves wrapping a simple measuring tape around the hand in a specific way, may be an alternative. The aim of the study was to examine the reliability and validity of the figure-of-eight method of measuring hand size in women with BCRL. Twenty-four patients with hand swelling associated with BCRL participated. Two novice testers performed three 'blinded' figure-of-eight measurements and three volumetric measurements of each hand. In terms of intertester (between-tester) and intratester (within-tester) reliability, the intraclass correlation coefficients were all greater than 0.8 indicating high intra- and intertester reliability for the figure-of-eight method. For validity, a Pearson's moment correlation computed between the figure-of-eight and volumetric methods highlighted a statistically significant correlation of 0.7 between the methods for both testers. The figure-of-eight method was found to be a valid and reliable method of measuring hand swelling in this population.

Seeing the body distorts tactile size perception

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception.

The Impact of Body-Scaled Information on Grasping Action in Toddlers with and without Down Syndrome

Background and purpose: Studies of adults and typically developing (TD) children find the number of hands and fingers used to grasp an object is influenced by the relationship between object size and hand size. Children with Down syndrome (DS) between 3 and 11 years have shown no differences in number of hands (1 or 2 hands) used to grasp different sized objects compared to TD children when the object size was body-scaled. The purpose of this study was to examine whether body-scaled information affected the number of hands and fingers used to grasp different sized objects in toddlers with and without DS. Method: Ten toddlers were included, 5 DS ( = 16 mo) and 5 age-matched TD ( = 16.3 mo). Subjects were videotaped grasping 14 boxes, 1.4 cm to 13.5 cm. in size. Number of hands and fingers used for grasping were recorded. Descriptive statistics, t-tests and Spearman correlation coefficient were used to compare the differences between toddlers with DS and TD. Results: Toddlers with DS had significantly smaller hand length than toddlers without DS (p=.004 right hand, p=.007 left hand). As box size increased, both groups switched from one-hand to two-hand grasping. There was a significant difference between groups where this transition occurred (p=.02). However, when the body-scaled ratio between object size and hand size was considered, the differences between groups disappeared (t(8)=1.479; p=.18). Moreover, the number of fingers used to grasp boxes also increased with increasing box size across both groups (ρ=0.94). Conclusion: Toddlers with DS show similar body-scaled grasping pattern as their age-matched peers with TD indicating that the differences in grasping patterns between toddlers with and without DS may be attributed to differences in body size, besides the motor abilities.

Dissociated hypopituitarism after spontaneous pituitary apoplexy in acromegaly

Introduction:Pituitary apoplexy is an uncommon event and usually occurs in non-functioning pituitary tumors. Among the functioning tumors, prolactinomas are the ones most likely to apoplexy. Apoplexy in growth hormone (GH) producing adenomas is a very rare event with less than thirty cases reported worldwide.Objective:To describe a case of spontaneous pituitary apoplexy in acromegaly.Case Report:A 55 year old smoker male presented to the our outpatient clinic in 2004 with complaints of gradual onset increase in the size of hands and feet, bilateral knee pain, increased sweating and blurring of vision. Investigations uncovered diabetes mellitus by a casual blood glucose of 243 mg/dl and HbA1c of 8.5%. Growth hormone suppression test using 75 gram oral glucose showed a 60 minute growth hormone of 105 ng/ml. Magnetic resonance imaging of the sellar region showed a 12.0 mm × 10.0 mm pituitary adenoma. The patient was planned for transsphenoidal tumor decompression. However, the patient was lost to follow up. Eight-years later, he presented in the emergency department of our institute with sudden onset headache, vomiting and decreased level of consciousness of one day duration. CT scan of the head with focus on the sella was suggestive of apoplexy which was later confirmed by the MRI of the sellar region.Conclusion:Although acromegaly can remit following apoplexy of the responsible pituitary adenoma, long term follow up is needed for early detection of the development of deficiency of pituitary hormones which may occur over years following the event as well as to detect tumor regrowth which again may occur several years later.

Healthcare access and the patterns of maternal health care utilization among poor and non-poor women living in urban areas in Portugal

Introduction: Studies on attitudes and practices are increasingly used but not specifically related to the motivations for the use of reproductive health care among women of fertile age, living in urban areas and in different social contexts. Objectives: The aim of this study was to estimate the associations between the variables of social status (degree of poverty in the studied groups) and the variables of fecundity (representations, tensions, practices and control of fertility) and, in addition, to compare access to health care in the different studied groups, assessing the association between use of maternal health care and poverty in urban areas. Design: A case-control study was conducted in the Municipality of Lisbon, Portugal, with a total sample of 1513 women of fertile age: 499 cases of women considered very poor were selected from the database of beneficiaries of RSI (Social Welfare Payment for Inclusion); 1014 controls (two controls for each selected case), divided as 507 poor women selected from the other beneficiaries of Santa Casa da Misericordia in Lisbon and 507 non-poor women selected from four Health Centers from the Municipality of Lisbon, Portugal. A total of 1054 women answered the questionnaire: 304 cases (response rate of 61%) and 750 (response rate of 74%) controls. The statistical analysis involved descriptive analysis and multinomial logistic regression. Results: The analysis confirms the association between poverty and patterns and representations of fecun dity regarding pregnancy planning. The results of this study thus show the existence of different distributions on several variables and the gradients of poverty. Regarding access to health care, the major impact of poverty on women is limiting access to pharmaceuticals. The incapacity to afford the cost of health care appears as a central aspect of access to health care. Conclusion: A number of factors seem to be associated with poverty in women, such as ethnicity, single motherhood, low household income, low household size, low educational level of women and marital status. The association of poverty with not planning the pregnancy of the last child on one hand and large household size on the other hand points to a vicious circle that sustains poverty and leads to extreme poverty. Limited financial access to health care seems to mediate the association between women’s poverty and low coverage with family planning as well as the lack of access to safe termination of pregnancy.

Effect of Hand Size on the Stimulation Intensities Required for Median and Ulnar Sensory Nerve Conduction Studies

ObjectivesTo examine the effect of hand size on median and ulnar sensory nerve conduction study (NCS) stimulation intensities and pain scores. DesignProspective, single group design to compare main outcomes by using a standard distance of 14cm versus the proximal wrist crease in 3 different hand sizes. SettingElectrodiagnostic laboratory in a department of rehabilitation medicine. ParticipantsHealthy volunteers (N=25) aged 20 to 30 years. InterventionsHand size was determined, based on the distance between the proximal wrist crease and the base of the long finger, resulting in 3 groups (≤11cm, >11–12cm, >12cm) with 12 hands per group. Antidromic median and ulnar sensory NCSs were performed. The nerves were randomly stimulated at the proximal wrist crease and 14cm from the recording electrode. Main Outcome MeasuresSupramaximal stimulation intensities and 10-cm visual analog scale (VAS) pain scores at each stimulating site were recorded and compared. ResultsThirty-six hands from 25 young healthy volunteers were studied. There was no correlation between the body mass index (BMI) and stimulation intensity, and BMI and VAS (r<0.3) in both median and ulnar nerves. Overall analysis showed that the stimulation intensity and VAS at 14cm were significantly greater than at the proximal wrist crease. Subgroup analysis showed the same result in all groups for the median sensory NCS, but in only the small hand group for the ulnar sensory NCS. ConclusionsWhen the same distance is used for NCSs regardless of patient size, smaller individuals required greater stimulation and reported greater discomfort. This may reflect greater nerve depth and suggests that one size fits all may not be the best approach with NCSs.

Bone histology of aquatic reptiles: what does it tell us about secondary adaptation to an aquatic life?

Aquatic reptiles are very diversified in the fossil record. The description and pooling of certain bone histological features (collagenous weave and vascular network) of the various groups of aquatic reptiles highlight what this histological information can tell us about the process of secondary adaptation to an aquatic life. Notably, they show the absence of interaction between these histological features on the one hand and body size, mode of swimming, type of microanatomical specialization and phylogeny on the other. These histological features in aquatic reptiles seem to essentially provide information about the growth rate and basal metabolic rate of these taxa. The growth rate seems to have been rather high in most marine reptiles, when compared with terrestrial ectotherms. Moreover, distinct metabolic abilities are suggested. Indeed, various groups probably displayed a peculiarly high body temperature, and some show trends towards endothermy. This study also emphasizes the crucial need for homologous comparisons in histology and shows that much remains to be done to better understand the relationship between histological features, growth rate and metabolism in extant taxa in order to make inferences in the fossil groups. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●●, ●●–●●.

What to do with NOECS/NOELS-prohibition or innovation?

This study attempted to be as realistic as possible when evaluating third-hand PAH residues resulting from 1 cigarette. Smokers were not asked to change their smoking habits, except to continuously hold the cigarette in 1 hand during the entire duration of the cigarette’s burning. Hand size (that is, the adsorptive surface area), duration of smoking, and environmental conditions such as wind, temperature, and humidity, in addition to other factors, may potentially influence PAH concentration. We conducted our third-hand smoke studies outdoors under environmental conditions, and therefore hypothesize that a similar study conducted in the more stable conditions of an indoor environment may reveal higher levels of contaminant residues on surfaces and smokers’ bodies. Moir et al. (2008) quantified PAH concentrations in second-hand tobacco smoke, defined as environmental tobacco smoke that is inhaled involuntarily or passively by someone who is not smoking. Using their study and our data set, we carried out a ‘‘back of the envelope’’ calculation to estimate the percentage of sidestream smoke (i.e., secondhand smoke) that becomes third-hand smoke. We conclude that the PAH inventory on 1 hand of a smoker represents 0.1% to 6% of that emitted from sidestream smoke. Third-hand PAH residues on a smoker’s hand represent only a fraction of the total PAH reservoir for a smoker (compared to residues on all exposed skin and clothing). We have begun to quantify this load of chemicals as the first step in assessing the potential for smokers to act as vectors for impairment of indoor air quality. To completely capture the health risk posed by third-hand smoke, further studies from our research group and others need to address the off-gassing or desorption potential of these compounds and more fully evaluate the significance of third-hand smoke residues in impairing indoor air quality and/or increasing PAH exposure to subpopulations such as children. A thorough ranking of the importance of this exposure route compared to other exposures modes (e.g., release of PAHs from cooking methods such as open fires, incense burning, indoor tobacco smoking, etc.) also remain to be quantified.

The Impact of Body-Scaled Information on Reaching

Environmental and task modifications are powerful methods used to affect action in rehabilitation and are frequently used by therapists. The purpose of this study was to examine and quantify the relationship between hand size (person characteristics) and object size (environmental characteristics) and the effect of this relationship on the emergent reaching patterns for children and adults with typical development. This was a cross-sectional prospective study. Seventeen children and 20 adults participated and were required to reach and grasp 10 pairs of cubes of different sizes. The dimensionless ratios were calculated by dividing the cube size by the aperture between index finger and thumb to quantify emergent reach and grasp patterns. A critical ratio was used to establish the shift from a 1-handed to an exclusive 2-handed reach pattern. The results demonstrated no significant difference in the mean critical ratios between the 2 groups. However, a 2-handed reach was used more frequently than a 1-handed reach at a significantly smaller ratio for children in comparison with adults. The relational metrics between the cube and hand are only one contribution to the emergent reaching and grasping patterns. Children had more variability of reaching patterns than adults. A personal constraint, such as experience, and a task constraint of accuracy may account for the variability. The results encourage further research on body-scaled information for individuals with different personal constraints (eg, children with cerebral palsy) and the impact of body-scaled information on emergent actions.

Modulating pain with augmented reality

Abstract Background/aims Being able to modulate pain through visual input raises the possibility that visually distorting body size also will reduce pain. The aim of the present study was to investigate whether experimental cold/heat pain could be modulated through a visual illusion of an increased/decreased hand size and whether pain perception correlated with the perceived sense of control of movement. Methods 20 healthy right-handed volunteers were recruited. Hand sizes were modulated through an AR setting designed to act as a mirror. Four conditions were included: (1) No AR setting; (2) left/right hands were the same size; (3) left hand enlarged; (4) left hand decreased. Pain thresholds (PT) for both hands were alternately assessed using two thermodes, placed on each palmar side of the hands. After each condition subjects rated the following statement: “I could control the movements of my left/right hand”. Results Heat pain: no main effect for conditions or hands (left/right). Cold pain: Significant main effects for conditions, but not for hands – condition (2) is significantly more painful than all conditions. Control of movements when the left hand is stimulated: the more control subjects have of right hand in condition (4), the higher the cold PT for the left hand in conditions (1) and (2). Control of movements when the right hand is stimulated: the more control subjects have of the right hand in condition (4), the higher the heat PT in the right hand for condition (2). Conclusions Visual illusions can modulate pain, however the modulating factors do not only depend on the size of the limbs that are been viewed but also on how much control subjects feel they have of the movements in their hands-specifically the relationship to the right hand condition (4) seems to have an analgesic effect for cold pain and heat pain.

Correlates of Multiple Placements in Foster Care: A Study of Placement Instability in Five States

In order to assess the consistency of correlates of multiple placements, secondary data from the Adoption and Foster Care Analysis and Reporting System (AFCARS) were examined for five states. The relationships between multiple placements and age, disability, and maltreatment type were consistent across the states studied. On the other hand, gender, race, and foster care system size were inconsistently related to multiple placements in terms of direction and/or strength. These results point to the importance of considering not only the strength and direction of these relationships, but also the enduring or shifting nature of these relationships across environments.

Vestibular stimulation modifies the body schema

Mental body representations are flexible and depend on sensory signals from the body and its surrounding. Clinical observations in amputees, paraplegics and brain-damaged patients suggest a vestibular contribution to the body schema, but studies using well-controlled psychophysical procedures are still lacking. In Experiment 1, we used a tactile distance comparison task between two body segments (hand and forehead). The results showed that objects contacting the hand were judged longer during caloric vestibular stimulation when compared to control thermal stimulation. In Experiment 2, participants located four anatomical landmarks on their left hand by pointing with their right hand. The perceived length and width of the left hand increased during caloric vestibular stimulation with respect to a control stimulation. The results show that the body schema temporarily adjusts as a function of vestibular signals, modifying the internal representation of the hand size. The data provide evidence that vestibular functions are not limited to postural and oculomotor control, and extend the contribution of the vestibular system to bodily cognition. The findings from this study suggest the inclusion of vestibular signals into current models of body representations and bodily self-consciousness.