Normal Human Variation

This phenomenological study investigated barriers to higher education faced by 11 college students labeled with learning disabilities (LD) using their voice as the primary data. Data were analyzed and interpreted through a disability theory perspective revealing barriers stemmed largely from external social causes rather than individual pathology. Barriers included being misunderstood by faculty, being reluctant to request accommodations for fear of invoking stigma, and having to work considerably longer hours than nonlabeled peers. Findings indicated barriers could be overcome through raising faculty awareness about LD issues, engaging the assistance of the college LD specialist, and participation in a LD democratic empowerment community on campus.

Dyslexia is a natural part of our human community flowing into all the world’s cultures and languages through many different genetic pathways (Biotechnology, 2007). Although statistics vary widely from source to source, estimates suggest about one in every seven people have some of the attributes of dyslexia (Eden & Zeffiro, 1998). We know that 10 percent of US children have been clinically identified as having some form of “learning disability” (Altarac & Saroha, 2007). Considering that clinical diagnosis is expensive and difficult to undertake, chances are that a larger percentage of people go unidentified. Many dyslexics manage to go through k-12 and even well into college before discovering it. Eighty-five percent of the informants in one of my studies did not know they could be labeled with any kind of LD until they were well into college. One of them discovered it in her senior year. Ultimately, we cannot know the exact frequency of dyslexia until geneticists identify the specific genes carrying it into the human population. We know that people with dyslexia encounter the world differently as they see, listen, speak, remember, and use their muscles. They also have more allergies or other autoimmune system issues like diabetes or thyroid imbalances (Benasich, 2002). On the positive side, we know that dyslexics are better at humor as well as creative approaches to problem solving (LaFrance, 1997).  Still, even after 50 years of medical research we know very little about how people with dyslexia view the world. Up to this point research has almost entirely been a matter of observing people with dyslexia and assuming their experience rather than asking them for their perspective. However, an exciting new research field is emerging to seek the voice of those with dyslexia and it is doing so with gusto. Early findings from the new field suggest that dyslexia might not be so much a dysfunction as it is a normal part of healthy, human variation misunderstood as disabling. Findings suggest that in the right context it is not a disability at all. The new field redirects us to understand dyslexia as something that serves humanity.
This paper reviews findings from medicine and other traditional fields of research, then moves into the critical perspective of Disability Studies where brain research is interpreted very differently and LD is demonstrated to be a socially constructed disability. Here, the barriers arise from misunderstanding, intolerance, and discrimination rather than physical pathology. In this view democracy is considered the most important tool for remediation.

This study assesses sexual dimorphism of the skull in samples of African-Americans (AA) and European-Americans (EA). Morphology of the cranium is classically referenced as an indicator of sexual dimorphism in the fields of bioarchaeology and forensic anthropology. Variation in size and shape of cranial elements has been found to differ significantly between ancestral populations. Abundant research suggests that patterns of sexual dimorphism also vary between ancestries. This study uses a sample of 55 AA females, 50 AA males, 49 EA females, and 49 EA males from the Hamann-Todd Collection at the Cleveland Museum of Natural History and the WM Bass Donated Collection at the University of Tennessee, Knoxville. Twenty linear measurements were taken on the cranium and mandible, and 19 variables were analyzed. MANOVA determined that four variables (i.e. maximum cranial length, maximum cranial height, cranial base length and mandibular angle) have significant interaction between sex and ancestry, thereby, corroborating the evidence that there is ancestral variation in sexual dimorphism. The results of this study have implications for understanding evolution among anatomically modern humans after having migrated out of Africa. Additionally, the knowledge gained from this study further assists forensic anthropologists and bioarchaeologists in reconstructing biological profiles of individuals and pre-historical populations by providing a detailed description of the variation in sexual dimorphism between African-Americans and European-Americans.

James Overboe (2007) and Fiona Kumari Campbell (2008, 2009)  noted that disabled people experience reality through the prism of a 'normative shadow' which assumes the preferability of abledness and holds that disability is inherently negative and harmful. Whilst disabled people may experience periodic acute attacks on the integrity of their person in the form of hate crimes & the denial of access to goods and services, Campbell (2009) has argued that day-to-day, business as usual experiences of ableism not only wear disabled people and their families down, but can lead to internalised ableism. This seminar extends Campbell’s work through a discussion about the strategy to promote resiliency skills in the lives of disabled people to firstly reduce the effects of ableist harms/oppression and secondly as a tactic of resistance.

"It is argued in this article that the human body both in health and disease cannot be fully understood without adequately accounting for the different levels of human variation.The article focuses on variation due to ancestry, arguing that the inclusion of information pertaining to ancestry in human anatomy teaching materials and courses should be carried out and implemented with care and in line with latest developments in biological
anthropology and related sciences. This seems to be of particular importance in the education of health professionals, as recent research suggests that better knowledge of human variation can improve clinical skills. It is also argued that relatively small curricular changes relating to the teaching of human variation can produce significant educational
gains."

ABSTRACT: Cleft lip and palate (CLP) is a craniofacial malformation affecting more than seven million people worldwide that results in
defects of the hard palate, teeth, maxilla, nasal spine and floor, and maxillodental asymmetry. CLP facial soft-tissue depth (FSTD) values
have never been published. The purpose of this research is to report CLP FSTD values and compare them to previously published FSTD
values for normal children. Thirty-eight FSTDs were measured on cone beam computed tomography images of CLP children (n = 86;
7–17 years). MANOVA and ANOVA tests determined whether cleft type, age, sex, and bone graft surgical status affect tissue depths. Both
cleft type (unilateral/bilateral) and age influence FSTDs. CLP FSTDs exhibit patterns of variation that differ from normal children, particularly
around the oronasal regions of the face. These differences should be taken into account when facial reconstructions of children with CLP are created.

The issue of human variation has recently become of great interest in medical research and practice, but numerous disagreements and misunderstandings surround this complex subject. It might be argued that these negative aspects could be reduced significantly if elements of human variation were taught to medical students. Even small changes in curriculum, if efficiently implemented, could produce considerable gains.

Canthal measurements are important tools to craniofacial anthropologists, clinical geneticists and reconstructive surgeons and vary within and between individuals. The aim of this study is to determine the differences of the canthal measurements within and between children of two ethnic groups in Nigeria. The study samples were Yoruba and Igbo children between the ages of 5-16 year residing in Kano metropolis in Kano state of Nigeria. Inner canthal distance (ICD) and outer canthal distances (OCD) were measured in mm, using Facial landmark detection software from Bayero University Kano, version 1.0.0.0 program for Windows operating system. Canthal index (CI) was calculated using the standard formula. The data obtained were subjected to statistical analysis; and independent sample t-test. P value of <0.05 was considered statistically significant. Sexual dimorphism was observed in OCD within Yoruba ethnic group with males having significantly higher mean value, while Igbo males had higher insignificant mean value in OCD than Igbo females. The mean ICD were insignificantly higher in males than in females in both ethnic groups. In comparison of OCD and ICD between Yoruba and Igbo males and females, the Yoruba males and females had higher mean value than the Igbo males and females with no statistical significance. Yoruba females had higher insignificant CI value more than Yoruba males while Igbo males had higher insignificant higher CI value than Igbo females. The mean CI difference between Yoruba and Igbo children were statistically significant. Thus Canthal dimensions exhibit sexual dimorphism within and between ethnic group and may therefore be of use to esthetic surgeons.

This study asks whether or not sexual dimorphism can be expressed differently across human populations, particular among European-American (EA) and African-American (AA) skulls. Morphology of the skull is a classically referenced indicator of sex; and, variation of size and shape has been found to differ significantly between ancestral populations. Any information concerning variation in the expression of sexual dimorphism between ancestral populations would aid osteologists in estimating sex in individuals of both known and unknown ancestry. This study is divided into two phases. Phase 1 consists of a sample of 55 AA females, 50 AA males, 49 EA females and 49 EA males with mixed representation from the Hamann-Todd Collection at the Cleveland Museum of Natural History and the WM Bass Donated Collection at the University of Tennessee, Knoxville. Multivariate analysis of nineteen linear measurements suggests that sexual dimorphism is expressed differently between AA and EA in four of these measurements (i.e. cranial length, cranial height, cranial base length and mandibular angle). Phase 2 consists of a sample of 53 AA females, 48 AA males, 53 EA females and 57 EA males all from the Hamann-Todd Collection. In this case, multivariate analysis of four cranial measurements (i.e. cranial length, cranial width, cranial height and cranial base length) suggests that there is no difference in sexual dimorphism between AA and EA.  These paired findings offer insight into variation within and between defined populations as well as the effect of secular change on cranial morphology.

Knee injury is one of the major problems in sports medicine, and the use of prophylactic knee braces is an attempt to reduce the occurrence and/or severity of injuries to the knee joint ligament(s) without inhibiting knee mobility. The aim of the present study was to examine the effect of one recently designed prophylactic knee brace and two neoprene knee sleeves upon performance of healthy athletes. Thirty-one healthy male athletes (age = 21.2±1.5) volunteered as participants to examine the effect of prophylactic knee brace/sleeves on performance using isokinetic and functional tests. All subjects were tested in four conditions in a random order: 1. nonbraced (control) 2. using a neoprene knee sleeve 3. using a knee sleeve with four bilateral metal supports and 4. using a prophylactic knee brace. The study design was a crossover, randomized, controlled trial. Subjects completed single leg vertical jump, cross-over hop, and the isokinetic knee flexion and extension (at 60, 180, 300°/sec). Data were collected from the above tests and analyzed for jump height, cross-over hop distance, peak torque to body weight ratio and average power, respectively. Comparisons of these variables in the four testing conditions revealed no statistically significant difference (p>0.05). The selected prophylactic brace/sleeves did not significantly inhibit athletic performance which might verify that their structure and design have caused no complication in the normal function of the knee joint. Moreover, it could be speculated that, if the brace or the sleeves had any limiting effect, our young healthy athletic subjects were well able to generate a mean peak torque large enough to overcome this possible restriction. Further studies are suggested to investigate the long term effect of these prophylactic knee brace and sleeves as well as their possible effect on the adjacent joints to the knee. © 2012 Mortaza et al.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050110