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.

Tremor


Related Terms

  • Asterixis
  • Ataxic Tremor
  • Benign Hereditary Tremor
  • Cerebellar Tremor
  • Essential Tremor
  • Intention Tremor
  • Liver Flap
  • Parkinsonian Tremor
  • Physiologic Tremor
  • Postural Tremor
  • Resting Tremor
  • Senile Tremor

Differential Diagnosis

  • Acute anxiety disorder
  • Alcohol intoxication
  • Encephalopathies
  • Medication side effects
  • Multiple sclerosis
  • Parkinson's disease
  • Stroke (infarction)
  • Structural brain damage
  • Thyrotoxicosis
  • Tumors
  • Wilson's disease

Specialists

  • Neurologist
  • Psychiatrist

Comorbid Conditions

  • Liver failure
  • Neurological illness
  • Psychiatric disorders

Factors Influencing Duration

The severity of the tremor, underlying cause, effectiveness of the treatment, and job requirements affect the length of disability.

Medical Codes

ICD-9-CM:
781.0 - Symptoms Involving Nervous and Musculoskeletal Systems; Abnormal Involuntary Movements; Abnormal Head Movements; Fasciculation; Spasm NOS; Tremor NOS

Overview

A tremor is an involuntary, regular, shaking or twitching movement resulting from repeated contraction and relaxation of opposing muscle groups. It can be normal (physiologic) or abnormal (pathologic). A tremor may affect the fingers and hands, head, tongue, jaw, legs, and sometimes the trunk.

Tremors are classified according to their rate, strength, rhythm, distribution in the body, and time of occurrence, i.e., at rest (resting tremor) or during muscular activity (sustention or intention tremors). The term physiological tremor describes a fine, rapid tremor of outstretched hands and is usually associated with anxiety, stress, fatigue, alcohol withdrawal or hyperthyroid disorder (metabolic derangements), or the effects of certain drugs such as caffeine or corticosteroids. The term essential tremor (benign hereditary tremor) describes a slow tremor affecting the hands, head, and voice. This type of tremor is normally absent or mild at rest, and increases with activity. It may be isolated to one side of the body and tends to be associated with a family history of tremors. This is the most common tremor, and tends to worsen with age.

Abnormal tremors that occur during rest are generally classified as parkinsonian tremors. An individual may display one type of tremor or a combination of multiple types of tremors. For instance, a disorder affecting the liver cells called Wilson's disease is associated with both parkinsonian tremors and cerebellar tremors.

Several disorders that affect the coordination center of the brain (cerebellum) can result in tremors. Depending on the specific characteristics of the tremor, they may be termed intention, ataxic, or cerebellar tremors. For example, in multiple sclerosis an individual may display a tremor of the arm as it extends to reach for something. This is called an intention tremor. A sustension tremor is seen in proximal muscle groups when the individual attempts to sit or stand quietly. Task-specific tremor occurs when the individual attempts specific activities such as writing or speaking (primary writing tremor, vocal tremor). Psychogenic tremor is characterized by tremor that significantly decreases when the individual is distracted. Metabolic disturbances in the brain (encephalopathies) may cause an ataxic or cerebellar tremor characterized by a slow, nonrhythmic movement of an outstretched hand. This is also called asterixis. Since asterixis is most often seen in metabolic disturbances associated with advanced liver disease, it is sometimes referred to as "liver flap." Asterixis is not a true tremor.

Incidence and Prevalence: Incidence of Parkinson's disease is 4.5 to 21 per 100,000 per year (Minagar). Prevalence of multiple sclerosis is 350,000, with an annual incidence of 12,000 individuals in the US (Frohman).

Prevalence of essential tremor, the most common movement disorder, is 0.4% to 0.6% (Minagar). Prevalence of tremors in other associated conditions such as metabolic derangements, anxiety, or drug effects is sporadic and inconsistent.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Tremor is a common finding in Parkinson's disease, a disorder that usually begins in middle or later life and in some cases, may have a hereditary component. Resting tremor is present in 70% of individuals with Parkinson's disease (Minagar). Multiple sclerosis is a neurological disorder more common in females residing in temperate climates of the Northern Hemisphere. It typically arises in the third or fourth decade of life and is frequently associated with intermittent tremors.

Tremor may be a frequent feature of some of these disorders yet occurs sporadically in others. For example, tremor is a hallmark finding in essential familial tremor, a disorder that is not well understood but tends to develop in adolescence and may have a hereditary tendency. Peak onset of essential tremor occurs in the second or in the sixth decades of life (Minagar).

Source: Medical Disability Advisor



Diagnosis

History: The individual complains of involuntary shaking of different body parts such as hands, fingers, legs, feet, limbs, trunk, head, lips, or tongue. The individual may report history of drug or alcohol use or anxiety. They may mention a family history of tremor or other neurologic disease. History should focus on whether the tremor occurs when individual is engaged in voluntary motor activity, at rest, or maintaining a certain posture, and whether it disappears during sleep or is enhanced by stress.

Physical exam: A complete physical exam that includes testing of neurological function, reflexes, coordination, motor strength, and memory is needed for definitive diagnosis of the source of the tremor. Postural tremor is present with the limbs outstretched and usually disappears when the limbs are at rest. Physiologic tremor has a frequency of 8 to 12 cycles per second and is a form of postural tremor seen in normal individuals under certain conditions such as fear, anxiety, or after exercise; it can also occur in hyperthyroidism. Essential tremor is a form of postural tremor involving the limbs, head, and voice. Resting tremor has a lower rate than physiological tremor, with a frequency of 4 to 6 cycles per second, and is present at rest and disappears with action. It is often seen in parkinsonism where it characteristically appears as a "pill rolling" maneuver involving opposing circular movements of the thumb and index finger.

Tests: Electromyographic (EMG) studies may be indicated in some cases. Lab tests may include liver function studies, chemistry panel, and thyroid panel. If a structural cause in the brain is suspected, brain MRI or CT may be necessary.

Source: Medical Disability Advisor



Treatment

Treatment of tremor depends on its cause. Tremors associated with thyroid disorders, multiple sclerosis, or alcohol withdrawal will respond to treatment of the underlying condition and the correction of metabolic derangements.

Anti-anxiety medications may be useful for tremor associated with anxiety states. Beta-blocker drugs may be effective in treating benign tremors and physiologic tremor due to drugs or acute anxiety states (e.g., stage fright). Botulinum toxin A may be used to treat essential tremors. A variety of medications can manage tremors associated with Parkinson's disease. Levodopa (also called L-dopa) can replace the brain's dwindling supply of dopamine, a substance that helps coordinate muscle activity. Other drugs often used are anticholinergics or an antiviral agent (amantadine) that sometimes reduces the tremor. If unresponsive to medications, alternative treatments include selectively destroying a part of the thalamus using a high-frequency electrical shock (high-frequency thalamic stimulation). More recently, deep brain stimulation using an implanted electrode placed deep in the brain tissue can help control tremors without destroying brain tissue. It enables the individual to reversibly control abnormal brain function with an on/off magnetic device. There are no medications useful in treatment of cerebellar tremor; however, therapeutic activities including wearing weights on the affected limbs or bracing of proximal muscles may be helpful.

Alcohol, caffeine, and concentrated sugars should be avoided, as they tend to increase anxiety and tremor. Behavioral counseling may be recommended if the source of the tremor is related to drug or alcohol abuse.

Source: Medical Disability Advisor



Prognosis

Physiologic tremors that occur in various metabolic and toxic states are temporary and usually disappear once the underlying disorder is corrected. Essential tremor is often referred to as a benign tremor, but it may be disabling due to coordination problems like spilling of liquids and poor handwriting. Parkinsonian tremors occur in the setting of a chronic and progressive disorder. Current medical and surgical treatment does not cure the disease but may be successful in slowing the progression of the disorder or in alleviating the tremor. Consequently, over time, these types of tremors cause progressive deterioration of muscle coordination and seriously affect the individual's quality of life.

Source: Medical Disability Advisor



Rehabilitation

Depending on the cause and severity of tremor, physical and / or occupational therapy may be needed to help the individual cope with coordination difficulties. Physical therapists may treat resting tremors with instruction in relaxation techniques, functional activities incorporating rotational movements, and alternating upper or lower extremity motion (reciprocal patterns). When individuals have significant tremor while maintaining sitting or standing posture, treatment may focus on exercises to promote trunk control such as rhythmic stabilization exercises and weight shifting.

The rehabilitation program varies for individuals affected by tremors. The type, intensity, and progression of exercises depend on the specific disorder affecting the nervous system. If job duties require fine motor movements, job reassignment and vocational rehabilitation may be needed.

Source: Medical Disability Advisor



Complications

Complications depend on the underlying disorder causing the tremor. Persistent tremors or those that get progressively worse such as associated with Parkinson's disease can contribute to the development of depression, social withdrawal, sleep disturbances, and fatigue.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Providing more rest and a calm environment may be helpful. Safety considerations may affect whether an individual can perform his or her usual duties. Duties that require working at heights, with heavy equipment or motor vehicles, or hazardous occupations may have to be restricted or modified. If fine motor skills are required, reassignment may be necessary.

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:

  • Did individual present with symptoms consistent with the general diagnosis of tremor?
  • Was underlying cause of the tremor determined with a physical exam and diagnostic studies?
  • If diagnosis was uncertain, were all common causes of tremor considered in the differential diagnosis?
  • Would individual benefit from consultation with a specialist (neurologist, endocrinologist, physiatrist, internist, psychiatrist)?
  • Should EMG, brain MRI or CT, or other tests be done to assist with differential diagnosis?
  • Were a recent thyroid panel, liver function studies, and chemistry panel done to rule out functional or metabolic sources of the tremor?
  • Has individual complained of nervousness, feelings of anxiety, or depression?

Regarding treatment:

  • Was underlying cause of tremor addressed in treatment plan?
  • Was treatment appropriate for the condition?
  • Did symptoms persist? If so, were other or more aggressive treatments considered?

Regarding prognosis:

  • What was expected outcome?
  • Does individual have any comorbid conditions that may influence length of disability?
  • Is condition chronic or progressive in nature?
  • Does individual have any evidence of depression, social withdrawal or excess fatigue?
  • Does individual have access to support groups or behavioral counseling?

Source: Medical Disability Advisor



References

Cited

Frohman, Elliot M. "Multiple Sclerosis." Medical Clinics of North America 87 4 (2003): 867-897. MD Consult. Elsevier, Inc. 11 Oct. 2004 <http://home.mdconsult.com/das/journal/view/41505736-4/N/13661578?sid=293730909&source=MI>.

Minagar, Alireza, and Roger E. Kelley. "Movement Disorders." Clinics in Office Practice 31 1 (2004): 111-127. MD Consult. Elsevier, Inc. 11 Oct. 2004 <http://home.mdconsult.com/das/journal/view/41505736-4/N/14670448?sid=293730909&source=MI>.

Source: Medical Disability Advisor






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