Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Alzheimer's Disease


Related Terms

  • Alzheimer's Sclerosis
  • Presenile Dementia
  • Senile Dementia

Differential Diagnosis

  • Alcoholic dementia
  • Aphasia
  • Cortical basal ganglionic degeneration
  • Dementia in motor neuron disease
  • Dementia with Lewy bodies (DLB)
  • Depression
  • Drug overdose
  • Frontal and temporal lobe dementia
  • Hypothyroidism
  • Lyme disease
  • Multiinfarct dementia
  • Neurosyphilis
  • Parkinson's disease
  • Parkinson's-plus syndromes
  • Prion-related diseases
  • Thyroid disease
  • Vitamin deficiency
  • Wilson's disease

Specialists

  • Neurologist
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Psychiatrist

Comorbid Conditions

Factors Influencing Duration

Factors that may influence the length of disability include the general health and fitness of the individual before being diagnosed with AD, evidence of preexisting diseases affecting any of the major body systems (e.g., diabetes, chronic obstructive lung disease, and chronic heart disease), diagnosis of an acute disease or condition that requires surgery, the individual's mental and emotional stability, access to rehabilitation facilities and home health care, and the strength of the individual's support system.

Medical Codes

ICD-9-CM:
331.0 - Cerebral Degenerations, Other; Alzheimers Disease

Overview

Alzheimer's disease is a progressive, irreversible, degenerative organic brain disorder (dementia) characterized by loss of memory (subtle deterioration progressing to profound memory loss), loss of mental powers (the ability to think, understand, reason, learn, and solve problems), personality changes, and an increasing inability to carry out the activities of daily living (eating, bathing, grooming, dressing, and toileting).

The cause of the disease remains unclear. Acetylcholine, a neurotransmitter thought to be involved in learning and memory, is severely diminished in the brains of individuals with AD. The reason for this condition is unknown. In the past, it was believed that excessive levels of aluminum contributed to the development of AD, but today there is no conclusive evidence to show that individuals with aluminum toxicity have a greater incidence of the disease.

Age is the most significant risk factor for the onset of AD. Scientists believe individuals who develop signs of AD before age 65 (early onset) have a variation of the disease that is genetically transmitted across multiple generations of the same family. Children who inherit any one of three genes (APP, Presenlin-1, or Presenlin-2) will develop the disease before age 65 and as early as their late twenties. A fourth gene (Apoe4) is a risk factor for early onset AD, but not everyone who inherits this gene develops the disease later in life. Although some forms of early-onset familial AD can appear as early as the third decade, familial cases account for less than 10% of all individuals with the disorder (Anderson).

Researchers are looking for a connection between Down syndrome and AD. Individuals with Down syndrome exhibit symptoms of AD at a much younger age than the general population (late forties or early fifties), and nearly all individuals with Down syndrome who live past the age of 60 develop the disease. At autopsy, the degenerative changes in the brains of individuals with Down syndrome are almost identical to the changes seen in the brains of individuals with AD. Previous head trauma or central nervous system infection may also predispose an individual to develop AD later in life.

Alzheimer's disease is the most common form of dementia, and was the sixth leading cause of death among US adults in 2007 (Anderson). It is now recognized as a major health problem in the US, particularly in individuals over the age of 65 (late onset). The number of individuals diagnosed with AD will increase dramatically as more of the population born after the end of World War II reaches the age of 65.

Incidence and Prevalence: An estimated 5.4 million individuals in the US have AD (Anderson). Among North American individuals over 65, 6% to 10% have moderate to severe dementia, and AD comprises two-thirds of those cases; the addition of milder cases doubles that percentage (Anderson). Countries with aging populations have rates similar to those in the US. Among Americans ages 65 and older, 20.8% of Hispanics, 18.8% of blacks, and 7.8% of whites will develop AD or other dementias (Anderson).

Source: Medical Disability Advisor



Causation and Known Risk Factors

It was thought that women have an increased risk of developing AD, but study results conflict and may simply reflect the fact that women generally live longer than men (Anderson).

Source: Medical Disability Advisor



Diagnosis

History: Because individuals with AD are often unaware of changes in their mental powers or behavior, their families and friends become key factors in relating histories during the diagnostic process. Early symptoms of AD may include short-term memory loss (the inability to recall recent events or new information), trouble finding the right words, or poor judgment. The cognitive symptoms of AD also include disorientation, confusion, yelling, and problems with reasoning and thinking. Behavioral symptoms include agitation, anxiety, delusions, depression, hallucinations, insomnia, and wandering.

The DSM-IV-TR requires the following for a diagnosis of dementia of the Alzheimer's type: an individual must display multiple cognitive deficits manifested by both memory loss and at least one of the following: language disturbance (aphasia), an impaired ability to perform physical activities despite intact motor function (apraxia), a failure to recognize or identify objects despite intact sensory function (agnosia), and problems connecting events, putting things in order, or thinking in abstract terms (executive function). These deficits cause significant impairment in relationships or at work and represent a significant decline from a previous level of functioning. The course of AD is marked by gradual onset and continuing cognitive decline. Cognitive deficits do not result from other central nervous system conditions that cause progressive problems in memory and cognition, systemic conditions that cause dementia, or substance-induced conditions, and do not occur exclusively during the course of a delirium. The disturbance is not better explained by another axis I disorder. The diagnosis code varies, depending on the presence or absence of a clinically significant behavioral disturbance. One of two subtypes must be specified: early onset (onset at age 65 years or below) or late onset (onset after age 65 years) (DSM-IV-TR).

The three stages that individuals with AD predictably move through are mild, moderate, and severe. During the mild stage, the individual may seem normal to the casual observer but is beginning to have a decline in memory and mental powers. In the middle stage, the individual is obviously impaired and requires a caregiver's supervision during the performance of daily activities; delusions, agitation, pacing, and wandering often develop during this stage. In the severe stage, the individual is unable to communicate, cannot recognize family members, has bowel and bladder incontinence, and is unable to perform the activities of daily living.

In individuals with Down syndrome, behavioral symptoms are sometimes more accurate warning signs of AD than cognitive symptoms. The most easily detected symptoms in individuals with Down syndrome are a sudden change in the ability to complete the activities of daily living, withdrawal from daily and social routines, aggression, frustration, and lack of interest in regular activities.

In the DSM-5, AD is included in the section Major and Mild Neurocognitive Disorders, stating that major or mild neurocognitive disorder due to AD demonstrates insidious onset and gradual progression of impairment in at least one cognitive domain (at least two domains for major neurocognitive disorder). Individuals meet the criteria for either probable or possible AD as follows:

For major neurocognitive disorder, the diagnosis of probable AD is made if family history or genetic testing reveal evidence of a causative AD genetic mutation, or all three of the following are present: clear evidence of decline in memory and learning and at least one other cognitive domain; steadily progressive, gradual decline in cognition without extended plateaus; and no evidence of mixed etiology. Otherwise, possible AD is diagnosed.

For mild neurocognitive disorder: the diagnosis of probable AD is made if family history or genetic testing reveals evidence of a causative AD genetic mutation. The diagnosis of possible AD is made if genetic testing or family history does not reveal evidence of mutation, but all three of the conditions listed in the previous paragraph are present.

AD is diagnosed when symptoms are not better accounted for by cerebrovascular disease, another neurodegenerative disease, the effects of a substance, or another mental, neurological, or systemic disorder (DSM-5).

Physical exam: The diagnosis of AD can only be confirmed by postmortem examination of brain tissue. The brain afflicted with AD exhibits significant atrophy, the presence of sticky protein plaques outside the nerve cells, and tangles (neurofibrillary tangles). For purposes of treatment, ruling out all other possible conditions that can cause mental impairment must be done before diagnosing for AD. In addition to a complete physical exam, psychological and neurological exams may also be performed. Depending on how advanced the disease is, physical examination can confirm some of the reported symptoms.

Tests: There are no definitive tests to positively diagnose AD. Laboratory tests such as a complete blood count (CBC), Vitamin B12 (cobalamin), liver enzymes, cortisol level in the blood, analysis of cerebrospinal fluid from a lumbar puncture, and rapid plasma reagin (RPR) are helpful in ruling out other etiologies of dementia. Computed tomography (CT) and magnetic resonance imaging (MRI) scans are usually performed and may reveal shrinkage of the brain (cerebral atrophy) and enlarged cavities (cerebral ventricles), but these signs are also found in other forms of dementia. Positron emission tomography (PET) and single photon emission computer tomography (SPECT) are sometimes used to measure the rate of brain cell metabolism. An electroencephalogram (EEG) can establish the diagnosis as well. Neuropsychological testing such as the Mini-Mental Status Examination (MMSE) is performed to determine the extent of cognitive dysfunction. Additional tests that may be performed to rule out other diseases include blood tests, a chest x-ray, and thyroid function tests.

Note: It must be kept in mind that just because a physical diagnosis cannot be established as the cause of the presenting symptomatology, it does not necessarily mean that the cause is a mental one. That is to say that the presence of medically unexplained symptomatology does not necessarily establish the presence of a psychiatric condition. The first step in identifying the presence of a mental disorder is excluding the presence of malingering and/or of factitious disorder. Although factitious disorder is conscious and purposeful, it is classified as a psychiatric disorder. The strong need for this step is especially true whenever there is a medicolegal context associated with the presenting problem(s). Additionally, using DSM-5 and/or ICD-9-CM or ICD-10-CM, the clinician will find that many presentations fail to fit completely within the boundaries of a single mental disorder. There are systematic ways to go about making psychiatric diagnoses, however.

Source: Medical Disability Advisor



Treatment

The pharmaceutical treatment of AD is aimed at improving and controlling the decline in mental powers (cognition) and the undesirable behavioral symptoms that the individual may exhibit. Several anticholinesterase inhibitors may modestly slow the decline in cognitive function during the early or middle stages of AD. Other helpful drugs are on the horizon, but some of these drugs are toxic to the liver and require frequent laboratory monitoring of liver function. Memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has recently received approval for the treatment of moderate and severe stages of AD.

Unfortunately, no pharmaceutical treatments are available for the disease's late stages. Studies have shown that estrogen may help protect against the development of AD and may slow progression in those who already have the disease. However, a study of women over 65 with normal cognition indicated that estrogen may increase the risk of dementia (Anderson). Any depression that may accompany AD can be treated with antidepressants, particularly the newer selective serotonin re-uptake inhibitors.

In most cases, individuals with AD do not noticeably improve but rather gradually deteriorate as they lose their mental and physical capacities. The goal of treatment and rehabilitation is to support the individual in performing daily activities and to forestall further deterioration in memory and mental powers for as long as possible. For those individuals who are sufficiently aware of their situation, early diagnosis offers an opportunity to plan retirement from work, arrange for management of their finances, and discuss the management of future medical problems while they are still competent. Skilled, supportive care may improve the quality of the individual's life. Current research focuses on early diagnosis and treatment.

Source: Medical Disability Advisor



Prognosis

The general course of AD, from the mild stages to death, averages 8 to 10 years. Death usually occurs as a result of another disease or injury brought on by the individual's weakened condition.

Source: Medical Disability Advisor



Rehabilitation

Individuals with AD may require occupational therapy to help compensate for cognitive deficits. This type of therapy focuses on maintaining realistic caregiver goals and maximizing safety in the home. Individuals and their caregivers learn to structure the individual's environment to allow for greater independence. Individuals can perform daily tasks better if the environment does not change and the tasks are performed as part of the same daily routine.

Individuals aware of their memory loss can compensate for forgetfulness by writing notes to remember daily tasks. Caregivers also learn to provide time cues such as a clock. Occupational therapy does not ordinarily focus on teaching new skills to individuals with AD because this disease decreases problem-solving ability.

Individuals aware of their memory loss may require psychological counseling to help treat the depression that often accompanies this disease. Group counseling may be necessary for individuals and their families to address the anger and aggressiveness that individuals with AD often exhibit. Support groups can address individuals' concerns about their prognosis.

Source: Medical Disability Advisor



Complications

Individuals with AD are susceptible to all the acute and chronic diseases and conditions common to the elderly and physically disabled population, including cancer, heart and vascular disease, stroke, blood clots, choking and aspiration, infectious disease, diabetes, respiratory disease, and neuromuscular complications associated with decreased mobility. Since these individuals are often unable to communicate health symptoms, caregivers must be responsible for alerting the individual's physician to changes in behavior, movement, consciousness, and bodily functions.

Individuals with AD are also at increased risk for injury associated with impaired judgment; violence directed at others as a result of neurologic changes (disinhibition), sensory overload, lack of appropriate coping mechanisms, and an unfamiliar environment; gait instability, muscle weakness, and sensory and perceptual changes. Recurrent falls are commonly seen in later stages. If surgical intervention is required for any of these conditions, the individual is subject to the usual surgical complications (infection, adverse reaction to the anesthetic, pneumonia, and poor wound closure). The tendency to wander away from caretakers and familiar surroundings puts these individuals at risk for traumatic injury, drowning, victimization, and death from unnatural causes.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Very early in the course of the disease, limited work activities may be possible, depending on the nature of the work and the individual's degree of deficiency in areas critical to the performance of a particular job. In most cases, however, a plan for retirement may need to be arranged fairly soon after the diagnosis of AD.

Risk: Risk of working with early-stage AD includes forgetfulness and impaired cognitive skills that may affect the safety of the individual and his or her coworkers; individuals with AD should be removed from safety-sensitive job tasks for this reason. A structured work environment with familiar job duties may allow the individual to continue working until the disease progresses, after which time the individual will no longer be able to safely perform any job tasks.

Capacity: Capacity will be progressively affected by confusion, loss of judgment, and short-term memory loss. As individuals lose their mental and physical capacities, work capacity is also lost.

Tolerance: Individuals with early-stage AD who are aware that they are becoming forgetful may improve work tolerance by using clocks, calendars, and other external cues to compensate for their short-term memory loss. As the AD progresses and work capacity is lost, tolerance is no longer a factor.

Source: Medical Disability Advisor



Maximum Medical Improvement

The typical course for Alzheimer’s is one of progression. Sometimes with treatment there are brief plateaus, but generally speaking, MMI is not a concept that would apply to this disorder.

Note: MMI is estimated under the assumption that the vagaries involved in psychiatric diagnoses have been taken into consideration.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Was a presumptive diagnosis of AD made?
  • Were underlying medical and psychological conditions identified or ruled out?
  • Is caregiver diligent in alerting individual's physician to changes in behavior, movement, consciousness, and bodily functions?
  • Has individual experienced health-related complications?
  • How are coexisting conditions being addressed?

Regarding treatment:

  • To what extent is individual impaired?
  • Can individual and/or family members still adequately care for needs? Would family benefit from social services in making long-range plans? Has family accessed appropriate services to care for individual?

Regarding prognosis:

  • Are individual and family realistic in planning for the future?
  • Will family be able to care for individual in home?
  • Were other options investigated?

Source: Medical Disability Advisor



References

Cited

Diagnostic and Statistical Manual of Mental Disorders (DSM-5). 5th ed. American Psychiatric Association, 2013.

Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). 4th ed. Washington, DC: American Psychiatric Association, 2000.

Anderson, Healther S. "Alzheimer Disease." eMedicine. 29 Apr. 2015. Medscape. 8 Jun. 2015 <http://emedicine.medscape.com/article/1134817-overview#showall>.

Source: Medical Disability Advisor






Feedback
Send us comments, suggestions, corrections, or anything you would like us to hear. If you are not logged in, you must include your email address, in order for us to respond. We cannot, unfortunately, respond to every comment. If you are seeking medical advice, please contact your physician. Thank you!
Send this comment to:
Sales Customer Support Content Development
 
This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is published with the understanding that the author, editors, and publisher are not engaged in rendering medical, legal, accounting or other professional service. If medical, legal, or other expert assistance is required, the service of a competent professional should be sought. We are unable to respond to requests for advice. Any Sales inquiries should include an email address or other means of communication.