Sensory disability

According to many definitions, a disability is an impairment that may be cognitive, developmental, intellectual, mental, physical, sensory, or some combination of these. Other definitions describe disability as the societal disadvantage arising from such impairments. Disability substantially affects a person's life activities and may be present from birth or occur during a person's lifetime. Disability is a contested concept, with different meanings in different communities. It may be used to refer to physical or mental attributes that some institutions, particularly medicine, view as needing to be fixed (the medical model). It may refer to limitations imposed on people by the constraints of an ableist society (the social model). Or the term may serve to refer to the identity of disabled people. Physiological functional capacity (PFC) is a related term that describes an individual's performance level. It gauges one's ability to perform the physical tasks of daily life and the ease with which these tasks are performed. PFC declines with advancing age to result in frailty, cognitive disorders or physical disorders, all of which may lead to labeling individuals as disabled. For the purposes of the Americans with Disabilities Act of 1990, the Equal Employment Opportunity Commission regulations provide a list of conditions that should easily be concluded to be disabilities: deafness, blindness, an intellectual disability (formerly termed mental retardation), partially or completely missing limbs or mobility impairments requiring the use of a wheelchair, autism, cancer, cerebral palsy, diabetes, epilepsy, HIV/AIDS, multiple sclerosis, muscular dystrophy, major depressive disorder, bipolar disorder, post-traumatic stress disorder, obsessive compulsive disorder, and schizophrenia. Contemporary understandings of disability derive from concepts that arose during the West's scientific Enlightenment; prior to the Enlightenment, physical differences were viewed through a different lens. During the Middle Ages, madness and other conditions were thought to be caused by demons. They were also thought to be part of the natural order, especially during and in the fallout of the Plague, which wrought impairments throughout the general population. In the early modern period there was a shift to seeking biological causes for physical and mental differences, as well as heightened interest in demarcating categories: for example, Ambroise Pare, in the sixteenth century, wrote of 'monsters', 'prodigies', and 'the maimed'. The European Enlightenment's emphases on knowledge derived from reason and on the value of natural science to human progress helped spawn the birth of institutions and associated knowledge systems that observed and categorized human beings; among these, the ones significant to the development of today's concepts of disability were asylums, clinics, and, prisons. Contemporary concepts of disability are rooted in eighteenth- and nineteenth-century developments. Foremost among these was the development of clinical medical discourse, which made the human body visible as a thing to be manipulated, studied, and transformed. These worked in tandem with scientific discourses that sought to classify and categorize and, in so doing, became methods of normalization. The concept of the 'norm' developed in this time period, and is signaled in the work of the Belgian statistician, sociologist, mathematician, and astronomer Adolphe Quetelet, who wrote in the 1830s of l'homme moyen – the average man. Quetelet postulated that one could take the sum of all people's attributes in a given population (such as their height or weight) and find their average, and that this figure should serve as a norm toward which all should aspire. This idea of a statistical norm threads through the rapid take up of statistics gathering by Britain, United States, and the Western European states during this time period, and it is tied to the rise of eugenics. Disability, as well as other concepts including: abnormal, non-normal, and normalcy came from this. The circulation of these concepts is evident in the popularity of the freak show, where showmen profited from exhibiting people who deviated from those norms.