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Hand (New York, N.Y.) Jan 2021Digit replantation affords the opportunity to restore hand function following amputation. To date, however, few studies have evaluated functional outcomes following... (Meta-Analysis)
Meta-Analysis Review
Digit replantation affords the opportunity to restore hand function following amputation. To date, however, few studies have evaluated functional outcomes following replantation. Therefore, it was the objective of this study to perform a meta-analysis to better characterize the predictors of hand function. A literature search was performed using the PubMed database to identify studies that focused on digit amputation/replantation and functional outcomes. Studies were evaluated for patient- and injury-related factors and their respective effects on clinical outcomes of sensation, grip strength, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Statistical analysis was conducted across the pooled data set to identify significant trends. Twenty-eight studies representing 618 replanted digits were included in this study. We found the average grip strength was 78.7% (relative to contralateral), the average 2-point discrimination (2PD) was 7.8 mm, and the average DASH score was 12.81. After conducting statistical analysis, we found patients with more proximal injuries had lower grip strength scores ( < .05). We found 2PD scores were influenced by age, mechanism of injury, and amputation level ( < .05). Finally, we found DASH scores after replantation were predicted by mechanism of injury and level of amputation ( < .05). The following variables did not influence outcomes: gender, tobacco use, ischemia time, and digit number. Digit replant does not restore premorbid hand function but does result in adequate hand function. Expected functional outcomes following replant should be considered in the decision-making process. These data can help risk-stratify patients, guide postreplant expectations, and influence the decision for replantation.
Topics: Amputation, Surgical; Amputation, Traumatic; Finger Injuries; Humans; Replantation; Retrospective Studies
PubMed: 30938181
DOI: 10.1177/1558944719834658 -
Scientific Reports May 2021Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures,...
Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (D), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.
Topics: Female; Fingers; Functional Laterality; Humans; Infant; Male; Reproducibility of Results; Sex Characteristics
PubMed: 34040007
DOI: 10.1038/s41598-021-89590-w -
Scientific Reports Apr 2021Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of...
Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of allometry. The goal of our study is to verify the validity of these assumptions. The study sample comprised 7,582 individuals (3,802 men and 3,780 women) from three large world populations: Europeans (n = 3043), East Africans (n = 2844), and Central Asians (n = 1695). The lengths of the second and fourth digits on both hands were measured. Digit ratios were computed according to standard procedures. Analyses were conducted separately for each hand for the whole sample and in succession for the three large populations. Additionally, we separately tested four age cohorts (≤ 13, 14-18, 19-30, and 31 ≥ years) to test the effect of developmental allometry. The second and fourth digits showed strong positive linear relationships on both hands, and demonstrated an increase with age; digit length in women from the youngest age cohort was longer or equal to that of men, and shorter than men in older age cohorts. However, the 2D:4D magnitude and its sexual dimorphism remained stable throughout the ontogeny. To test for an allometric effect on 2D:4D, the average digit lengths were calculated. Both sex and population origin were permanent reliable predictors of 2D:4D, whereas average digit length was not. Height was applied as another measure of allometric effect on the limited sample (≤ 30 years) from the European population, along with sex and age. No allometric effect was observed in this case. We conclude that sex differences in 2D:4D are not an artifact of allometry.
Topics: Adolescent; Adult; Africa, Eastern; Age Factors; Aged; Aged, 80 and over; Asia, Central; Body Height; Child; Child, Preschool; Cross-Sectional Studies; Europe; Female; Fingers; Humans; Male; Middle Aged; Sex Characteristics; Young Adult
PubMed: 33854119
DOI: 10.1038/s41598-021-87394-6 -
Entropy (Basel, Switzerland) Oct 2022Related to the letters of an alphabet, entropy means the average number of binary digits required for the transmission of one character. Checking tables of statistical...
Related to the letters of an alphabet, entropy means the average number of binary digits required for the transmission of one character. Checking tables of statistical data, one finds that, in the first position of the numbers, the digits 1 to 9 occur with different frequencies. Correspondingly, from these probabilities, a value for the Shannon entropy H can be determined as well. Although in many cases, the Newcomb-Benford Law applies, distributions have been found where the 1 in the first position occurs up to more than 40 times as frequently as the 9. In this case, the probability of the occurrence of a particular first digit can be derived from a power function with a negative exponent > 1. While the entropy of the first digits following an NB distribution amounts to H = 2.88, for other data distributions (diameters of craters on Venus or the weight of fragments of crushed minerals), entropy values of 2.76 and 2.04 bits per digit have been found.
PubMed: 37420433
DOI: 10.3390/e24101413 -
NeuroImage Jan 2019The dominant model of number processing suggests the existence of a Number Form Area (NFA) in the inferior temporal gyrus (ITG) that supports the processing of Arabic...
The dominant model of number processing suggests the existence of a Number Form Area (NFA) in the inferior temporal gyrus (ITG) that supports the processing of Arabic digits as visual symbols of number. However, studies have produced inconsistent evidence for the presence and laterality of digit-specific ITG activity. Furthermore, whether any such activity relates to mathematical competence is unknown. This study investigated these two issues using functional magnetic resonance imaging. Thirty-two adults performed digit and letter detection tasks and reading and mathematics tests. During digit detection, participants determined whether digits were present in a string of letters (e.g., AH3NR versus AHTNR). During letter detection, participants determined whether letters were present in a string of digits (e.g., 93R78 versus 93478). Results showed four clusters in frontal, occipital, and temporal regions for digit detection, including a left ITG cluster. Five clusters in frontal, parietal, occipital, and temporal regions were associated with letter detection, including a left ITG cluster. Digit and letter-related ITG clusters were spatially distinct; however, a direct contrast of digit and letter processing did not reveal greater activity in the left ITG for digit detection. Whole brain correlations showed greater digit-related activity in the right ITG for participants with higher calculation skills, but there was no correlation between letter activity and calculation skills. Together, our results suggest functional localization, but not specialization, for digits in the left ITG and provide the first evidence of a relationship between calculation skills and digit processing in the right ITG.
Topics: Adolescent; Brain Mapping; Female; Functional Laterality; Humans; Magnetic Resonance Imaging; Male; Mathematical Concepts; Pattern Recognition, Visual; Temporal Lobe; Young Adult
PubMed: 30342974
DOI: 10.1016/j.neuroimage.2018.10.047 -
The Journal of Physiology Dec 2011More than 30 muscles drive the hand to perform a multitude of essential dextrous tasks. Here we consider new views on the evolution of hand structure and on peripheral... (Review)
Review
More than 30 muscles drive the hand to perform a multitude of essential dextrous tasks. Here we consider new views on the evolution of hand structure and on peripheral and central constraints for independent control of the digits of the hand. The human hand is widely assumed to have evolved from hands like those of African apes, yet recent studies have shown that our hands and those of the earliest hominids are very similar and unlike those of living apes. Understanding the limits of hand function may come from investigation of our last common ancestor with the great apes, rather than the great apes themselves. In the periphery, movement across the full range of joint space can be limited by mechanical linkages among the extrinsic muscles. Further, peripheral limits occur when the hand adopts some positions in which the contraction of muscles fails to move the joints on which they usually act; there is muscle 'disengagement' and functional paralysis for some actions. Surprisingly, the central nervous system drives the hand seamlessly through this landscape of mechanical limits. Central constraints on control of the individual digits include the spillover of neural drive to neighbouring muscles and their 'compartments', and the inability to make maximal muscle forces when multiple digits contract strongly which produces a force deficit. The pattern of these latter constraints correlates with amounts of daily use of each digit and favours enslaved extension to lift fingers from an object but selective flexion of fingers to contact it.
Topics: Hand; Humans; Motor Cortex; Movement; Muscle, Skeletal; Psychomotor Performance
PubMed: 21986205
DOI: 10.1113/jphysiol.2011.217810 -
Dementia & Neuropsychologia 2019The digit span test is widely used to assess attention and working memory. It is a portable, relatively culture-free and frequently used test. However, the cultural...
UNLABELLED
The digit span test is widely used to assess attention and working memory. It is a portable, relatively culture-free and frequently used test. However, the cultural validity of this test, particularly in the Indian older population, is not well established.
OBJECTIVE
This study explores the usefulness of the digit span test for Indian older adults with different levels of education.
METHODS
Two hundred and fifty-eight community-dwelling healthy normal older adults formed the sample of this study. All study participants were screened using a semi-structured interview schedule, the modified MINI Screen, the Indian version of the Mini-Mental State Examination, a measure of activities of daily living and the digit span test administered verbally.
RESULTS
The results indicated that participants with higher educational level performed significantly better than low-educated participants on the digit span test. Participants with low education often struggled with the digit span test and resorted to guessing the digits.
CONCLUSION
Our study clearly demonstrates that the digit span test can be useful for educated participants. However, its usefulness and ecological validity is questionable for those with low education and low literacy, warranting future research.
PubMed: 31073387
DOI: 10.1590/1980-57642018dn13-010013 -
Experimental Brain Research Apr 2011We explored how digit forces and indices of digit coordination depend on the history of getting to a particular set of task parameters during static prehension tasks....
We explored how digit forces and indices of digit coordination depend on the history of getting to a particular set of task parameters during static prehension tasks. The participants held in the right hand an instrumented handle with a light-weight container attached on top of the handle. At the beginning of each trial, the container could be empty, filled to the half with water (0.4 l), or filled to the top (0.8 l). The water was pumped in/out of the container at a constant, slow rate over 10 s. At the end of each trial, the participants always held a half-filled container that has just been filled (Empty-Half), emptied (Full-Half) or stayed half-filled throughout the trial (Half-Only). Indices of covariation (synergy indices) of elemental variables (forces and moments of force produced by individual digits) stabilizing such performance variables as total normal force, total tangential force, and total moment of force were computed at two levels of an assumed control hierarchy. At the upper level, the task is shared between the thumb and virtual finger (an imagined digit with the mechanical action equal to that of the four fingers), while at the lower level the action of the virtual finger is shared among the actual four fingers. Filling or emptying the container led to a drop in the safety margin (proportion of grip force over the slipping threshold) below the values observed in the Half-Only condition. Synergy indices at both levels of the hierarchy showed changes over the Full-Half and Empty-Half condition. These changes could be monotonic (typical of moment of force and normal force) or non-monotonic (typical of tangential force). For both normal and tangential forces, higher synergy indices at the higher level of the hierarchy corresponded to lower indices at the lower level. Significant differences in synergy indices across conditions were seen at the final steady state showing that digit coordination during steady holding an object is history dependent. The observations support an earlier hypothesis on a trade-off between synergies at the two levels of a hierarchy. They also suggest that, when a change in task parameters is expected, the neural strategy may involve producing less stable (easier to change) actions. The results suggest that synergy indices may be highly sensitive to changes in a task variable and that effects of such changes persist after the changes are over.
Topics: Adult; Analysis of Variance; Biomechanical Phenomena; Female; Hand; Hand Strength; Humans; Male; Psychomotor Performance
PubMed: 21331525
DOI: 10.1007/s00221-011-2590-6 -
Computational and Mathematical Methods... 2022Cryopreservation has been applied in the replantation of limbs with a minimal amount of muscle tissue replanted. And small composite tissues have also been reported to...
Cryopreservation has been applied in the replantation of limbs with a minimal amount of muscle tissue replanted. And small composite tissues have also been reported to be successfully replanted by preoperative cryopreservation. In this study, we aimed to study the effect of preoperative cryopreservation on digital survival after digit replantation. Accordingly, we collected and compared the demographic and clinicopathological characteristics of patients with digit injury of patients, and we observed no significant difference between the NT and CP patients of digital injury. We also investigated the records of successful digit replantation and other parameters which influenced the odds of digital survival of all recruited patients. Accordingly, we found that the number of survived digits was remarkably increased in patients in the CP group compared with that in patients in the NT group. And the number of patients requiring blood transfusion and the mean length of hospital stay were notably decreased in the CP group. And compared with other patient characteristics, the mechanism of injury (blade, crush, or avulsion) showed a remarkable difference between the two groups of digital failure. Moreover, we analyzed the correlations between patient characteristics and the odds of digit survival and found that compared with other basic characteristics of patients and their injury, the preservation temperature, especially cryopreservation, could significantly promote digital survival after replantation.
Topics: Adult; Blood Transfusion; Computational Biology; Crush Injuries; Cryopreservation; Female; Finger Injuries; Fingers; Humans; Length of Stay; Male; Middle Aged; Preoperative Care; Replantation; Retrospective Studies; Treatment Outcome
PubMed: 35295200
DOI: 10.1155/2022/2003618