All of the Disabilities named here are discussed in WhatDisability.com. They are grouped into 6 categories explained below.

 

          ADD/ADHD                        Cystic Fibrosis                      Mental Retardation

        Alzheimers Disease                       Deaf                          Multiple Sclerosis (MS)

             Amputation                         Depression                    Muscular Dystrophy (MD)

          Anxiety Disorder                       Diabetes                            Memory Loss

               Arthritis                          Down Sndrome                          Narcolepsy

       Asperger Syndrome                     Dwarfism                                Obesity

               Asthma                             Dyscalculia           Obsessive Compulsive Disorder

               Autism                                Dyslexia                         Parkinson's Disease

         Bipolar Disorder                    Eating Disorders                             Phobias

       Bleeding Disorders                        Epilepsy                               Renal Failure

             Blindness                             Fibromyalgia                         Rett Syndrome

          Blurred Vision                Growth Hormone Deficiency                Schizophrenia

            Burn Injury                          Hearing Loss                             Scleroderma

               Cancer                                HIV/AIDS                                  Scoliosis

             Cataracts                      Huntington's Disease                  Sickle Cell Anemia

          Celiac Disease                       Hypoglycemia                            Spina Bifida

          Cerebral Palsy             Juvenile Rheumatoid Arthritis             Spinal Cord Injury

Charcot-Marie-Tooth Disease            Kidney Disease                              Stroke

         Crohn’s Disease                  Learning Disabilities                         Tinnitus

  Chronic Fatigue Syndrome                     Lupus                            Tourette Syndrome

       Cleft lip and Palate                   Meniere's Disease                    Turner Syndrome

                         Traumatic Brain Injury                     Williams Syndrome

Deaf or Hard of Hearing

This is the type of condition in which an individual is fully or partially unable to detect or perceive at least some frequencies of sound that can typically be heard by others. Another aspect of hearing loss involves how clearly the sound is perceived opposed to how loud it is. In humans, that aspect is usually measured by tests of speech perception. These tests measure one's ability to understand speech and to detect sound. Hearing loss is categorized based on the type (sensorineural, conductive, or both), the severity, and by the age of onset. The loss can exist in only one ear (unilateral) or in both ears (bilateral).

A conductive hearing impairment occurs when something prevents the conduction of sound waves through the path of the outer ear, the eardrum, and the bones of the middle or inner ear. A sensorineural hearing impairment occurs when there is a dysfunction in the vestibulocochlear nerve or the inner ear. It can also come from damage to the part of the brain that process auditory signals which causes the sound to be heard at the normal level but to be unclear. This is called Central Hearing Impairment.

These dysfunctions happen at birth due to genetic or developmental abnormalities, or arise through trauma or disease during a person's life.

Hearing loss is categorized in this way:

• Mild:

  • for adults: between 26 and 40 dB HL
  • for children: between 20 and 40 dB HL
• Moderate: between 41 and 55 dB HL
• Moderately severe: between 56 and 70 dB HL
• Severe: between 71 and 90 dB HL
• Profound: 90 dB HL or greater

Hearing loss can also be classified by the "percentage of hearing loss" but this usually only used for legal purposes. Some take pride in their deafness or view themselves as a minority rather than a disability group.

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 Vision Impairment

Vision impairment is loss of vision to a degree that a person needs additional support beyond the use of eyeglasses or contacts in order to carry out their daily physical activities. There are a number of different conditions that can affect a person's eyesight. It could result from eye disease or health conditions. Diabetic Retinopathy is when tiny blood vessels in the retina are damaged by diabetes. Age-Related Macular Degeneration occurs when the cells that allow a person to see fine details, located in their retina, die. Glaucoma is a condition where to much fluid pressure rises in the eyes and damages the optic nerve. A Cataract occurs when the crystalline lens in a person's eye, or it's envelope, becomes clouded and obstructs the passage of light. Receiving prompt treatment for these conditions may prevent them from getting worse, which makes regular eye exams crucial.

In the United States, the terms "partially sighted", "low vision", "legally blind" and "totally blind" are used by schools, colleges, and other educational institutions to describe students with types of visual impairments that are considered disabilities. They are defined as follows:

1. Partially sighted indicates some type of visual problem, with a need of person to receive special education in some cases;

2. Low vision generally refers to a severe visual impairment, not necessarily limited to distance vision. Low vision applies to all individuals with sight who are unable to read the newspaper at a normal viewing distance, even with the aid of eyeglasses or contact lenses. They use a combination of vision and other sensesto learn, although they may require adaptations in lighting or the size of print, and, sometimes, Braille;
   1. Myopic - unable to see distant objects clearly, commonly called near-sighted or short-sighted
   2. Hyperopic - unable to see close objects clearly, commonly called far-sighted or long-sighted
3. Legally blind indicates that a person has less than 20/200 vision in the better eye after best correction (contact lenses or glasses), or a field of vision of less than 20 degrees in the better eye; and
4. Totally blind students learn via Braille or other non-visual media.

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Neurological Disorders

A neurological disorder is a disorder of the body's nervous system. It is a structural, biochemical or electrical abnormality in the brain, spinal cord, or in the nerves leading to or from them. All of these items makeup part of the central or peripheral nervous system. The central nervous system contains the brain, spinal cord, and retina. The peripheral nervous system consists of sensory neurons, clusters of neurons called ganglia, and nerves connecting them to each other and to the central nervous system. Even though the brain and spinal cord are protected by tough membranes and are enclosed in the bones of the skull and spinal vertebrae, and chemically isolated by the so-called blood-brain barrier, they are very susceptible if compromised. While neuroregeneration may occur in the peripheral nervous system, it is thought to be rare in the brain and spinal cord.

The causes of neurological disorder vary. Many are considered severe disabilities and can include genetic disorders, congenital abnormalities or disorders, infections, lifestyle or environmental health problems such as malnutrition, and trauma can cause brain injury, spinal cord injury, or nerve injury. 

They are classified based on their location.

Cognitive Disabilities

A cognitive disability is one that affects a person's process of thought. There are many social, environmental and physical causes for these disabilities. They can include genetic and chromosomal abnormalities, substance abuse during pregnancy, brain injuries or infection before, during or after birth, prematurity of birth, and nutritional problems.

A mental disorder is any condition that constitutes an impairment of an individual's cognitive, emotional, or behavioral functions, that are not a part of normal development or culture. They can be caused by social, psychological, genetic, and biochemical stimulants or other factors, such as an infection or head trauma. Some of these orders include psychotic disorder, mood disorder, adjustment disorder, anxiety disorder, impulse control disorder, and developmental disorders.

These disorders are categorized as learning disabilities, mental retardation, acquired brain injury, and neurodegenerative diseases. They can include extreme forms such as Down Syndrome or Dementia, or less severe forms such as ADD or Dyslexia. Those with more extreme cognitive disabilities often need assistance with aspects of daily living. Persons affected by less severe forms such as learning disabilities may learn to function through their disability, even to the point where their disability is unnoticeable or never even diagnosed.

Invisible Disabilities

An invisible disability is one that cannot actually be seen, may not be noticeable all the time, or is reoccurring. To be considered a disability it must substantially limit the person's physical activity.

They can include diabetes, chronic pain and fatigue, ADHD, renal failure, arthritis, multiple Sclerosis, Schizophrenia, sleep disorders, Lupus, Epilepsy, and Crohn's disease. Persons with these disabilities have a harder time getting people to understand and accept their disabilities.

Physical Disabilities/Deformity

 

A bodily malformation, distortion, or disfigurement.

Prenatal causes: Those disabilities that are acquired before birth. These may be due to diseases that have harmed the mother during pregnancy, or genetic incompatibilities between the parents.

Perinatal causes: Those disabilities that are acquired during birth. This could be due to prolonged lack of oxygen or the obstruction of the respiratory tract, damage to the brain during birth (due to the accidental misuse of forceps, for example) or the baby being born prematurely.

Postnatal causes: Those disabilities gained after birth. They can be due to accidents, infection or other illnesses.

  Source: Wikepedia