Impairment is defined by Americans Disabilities Acts of 1990 (ADA), American Medical Association (AMA) and The World Health Organization (WHO). Definition includes impairment caused by physical and mental illnesses. Impairment is a partial or complete loss of normal function of organ such as eye, ears, brain, extremities, heart and lungs. Impairment may cause disability. AMA defines disability as an alteration of an individual's capacity to meet personal, social, or occupational demands because of impairment. The WHO defines disability as limitation of normal activity, performance restrictions and unable to complete defined goals which create difficulty in the performance, accomplishment, or completion of an activity in the manner or within the range considered normal for a human being. Difficulty encompasses all of the ways in which the performance of the activity may be affected.
- Impairment of eyes following auto accident may cause limitation in seeing or complete blindness leading to permanent disability because of inability to ambulate from place to place and inability to do physical work.
- Impairment of ears causes decreased hearing or complete deafness. Injured/impaired individual may not be able to do manual, indoor and outdoor work which needs hearing to prevent accident or injuries or to even carry on with the work tasks. Such patients will be considered disabled for manual, some of the indoor, and all of outdoor work.
- Impairment caused by anatomical dysfunction of brain, speech, musculoskeletal system, cardiovascular system and respiratory system will lead to disability if individual is unable to perform his work requirements. According to AMA, impairment is alteration of an individual's health status, deviation from normal in a body part or organ system and it's functioning.
- Severe impairment such as paraplegia may not cause disability if individual is accountant, physician or legal advisor and is able to work 40 hours a week sitting in wheelchair.
- In few cases minor impairment may cause permanent disability. Surgeon or pianist is considered permanently disabled if unable to use the dominant hand.
- The Social Security Administration (SSA) defines impairment as an abnormality of anatomical, physiological and psychological function as defined by clinical and laboratory examination.
- SSA defines disability as condition that results in inability to engage in any substantial, gainful activity by reason of any medically determinable physical or mental impairment.
- Workers' compensation systems usually defines disability as a reduction in wage-earning capacity as a result of an injury, illness, or occupational disease that arose out of, or in the course of employment.
- Disability is independent of impairment. Disability is inability of employee to perform his duty as defined by his trade and training. Impairment rating described by AMA is not suppose to be used to define disability.
- Disability is either partial or total, and may be temporary or permanent.
- Social security allows disability if individual is medically considered unable to perform his duty. Social security does not differentiate partial or total disability.
- Workers compensation systems allows modification of job description so impaired worker can go to work as partially disabled if job allows him to work with impairment. Plumber if injured at work or had auto accident can go back to sedentary work like sitting and monitoring equipment.
- Impairment following auto accident more or less follows guidelines set by SSA.