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.

Narcolepsy


Related Terms

  • Sleep Epilepsy

Differential Diagnosis

Specialists

  • Clinical Psychologist
  • Neurologist
  • Pulmonologist

Comorbid Conditions

  • Psychiatric disorders
  • Seizure disorders

Factors Influencing Duration

Length of disability may be influenced by severity of symptoms, frequency of attacks, response to treatment, exposure to hazards (e.g., working at heights and around heavy equipment), and the individual's coping skills.

Medical Codes

ICD-9-CM:
347.00 - Narcolepsy, without Cataplexy; Narcolepsy NOS
347.01 - Narcolepsy, with Cataplexy
347.10 - Narcolepsy in Conditions Classified Elsewhere, without Cataplexy
347.11 - Narcolepsy in Conditions Classified Elsewhere, with Cataplexy

Overview

Narcolepsy is a sleep disorder with irrepressible, involuntary sleep episodes during usual waking hours. It is classically characterized by sudden sleep periods accompanied by a sensation of being unable to move (sleep paralysis); vivid, terrifying hallucinations (hypnagogic hallucinations); and sudden weakness or loss of muscle tone without loss of consciousness (cataplexy). Both the paralysis and hallucinations occur at the onset and at the end of sleep. While these attacks may last from a few seconds to more than an hour, the frequency varies greatly from daily episodes to attacks occurring years apart. Excessive daytime sleepiness and disturbed nighttime (nocturnal) sleep may also be present.

Narcolepsy is sometimes associated with another condition called sleep apnea, when a sleeping individual repeatedly stops breathing throughout the night.

Narcolepsy is a chronic, lifelong disorder that can be mildly inconvenient or severely disabling. In addition, it has physical and social ramifications that can be debilitating or life-threatening. Hazardous activities such as driving a car or operating machinery can become dangerous to both the individual self and to others.

Narcolepsy may be genetic, as it tends to occur in close relatives such as siblings. First-degree relatives (parent and child, siblings) of known narcoleptics have an incidence 10 to 40 times higher of narcolepsy than the general population (Baker).

Incidence and Prevalence: It is estimated that narcolepsy affects from 125,000 to 500,000 individuals in the US, although as few as 50,000 may be correctly diagnosed (Hayduk). Incidence is 0.02% to 0.18% in the general US population. Internationally, incidence is 0.02% to 0.05% in whites in the Czech Republic, Finland, United Kingdom, and France; it is higher in the Japanese general population (0.18%), and lower in Israeli Jews and Arabs (0.002%) (Baker).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Narcolepsy equally affects men and women. Symptoms can begin at any age but usually have a gradual onset between the ages of 15 and 35. It is fully established by age 25, but becomes less severe in old age.

Source: Medical Disability Advisor



Diagnosis

History: Symptoms and signs include excessive daytime drowsiness with recurring episodes of uncontrollable sleep during usual waking hours. Sleep paralysis and vivid hallucinatory dreams may occur at sleep onset. Seventy-five to eighty percent of individuals report sudden weakness or loss of muscle tone while awake (cataplectic attacks), which may result in a fall. Cataplexy is present in 70% of narcoleptics (Baker). There may be a family history for narcolepsy.

Individuals often report difficulty concentrating, memory problems, and blurred or double vision. Periods of amnesia during purposeful activity (automatic behavior) may also occur.

Narcolepsy is often difficult to diagnose because all individuals do not experience all the characteristic symptoms.

Physical exam: Aside from observing the individual during an actual episode of narcolepsy, there are no physical findings associated with this disorder.

Tests: Testing at a sleep disorder clinic is the most accurate way to confirm a diagnosis of narcolepsy. Various tests conducted include an analysis of the electrical activity of the brain (electroencephalogram or EEG), a record of eye movements during sleep (electroculogram or EOG), and a record of muscle activity (electromyogram or EMG). Rapid eye movement sleep (REM) recorded by the EOG along with the multiple sleep latency test (MSLT) can distinguish the rapid onset of REM sleep seen in narcolepsy. REM sleep (sleep associated with dreaming) has a quicker onset in individuals with narcolepsy.

Testing of cerebrospinal fluid (CSF) may show low levels of hypocretin-1 in individuals with symptoms of cataplexy.

Keeping a journal (sleep log) of sleep patterns for 2 to 3 weeks may be helpful in diagnosis of sleep disorders such as narcolepsy.

Source: Medical Disability Advisor



Treatment

Treatment is symptomatic. Stimulant drugs are used to control drowsiness and sleep attacks. Treatment of cataplexy, hypnagogic hallucinations, and sleep paralysis requires tricyclic antidepressant drugs known to suppress REM sleep activity. Careful evaluation, titration, and elimination of any potentially sedating prescription or nonprescription drugs or herbs should be considered. Individuals who have narcolepsy impacted by sleep apnea may benefit from a continuous positive airway pressure (CPAP) machine to help decrease daytime sleepiness.

Treatment is directed at controlling or reducing the number of sleep attacks and associated symptoms. Structured daytime napping can be part of the behavior modification used with drug therapy. Narcolepsy support groups can be helpful as well. Many individuals improve with maintenance of a regular sleep schedule at night.

Source: Medical Disability Advisor



Prognosis

Narcolepsy is a lifelong disorder that can be mildly inconvenient or severely disabling. Treatment is directed at controlling or reducing the number of sleep attacks and associated symptoms. The condition becomes less severe with old age.

Source: Medical Disability Advisor



Complications

Complications from narcolepsy can arise if the condition is not adequately controlled by medication and a structured sleep schedule, and may include depression, reduced libido, and chronically disrupted sleep patterns.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Due to sudden periods of uncontrollable drowsiness or sleep attacks, individuals may not be able to work in positions where safety is a concern. Job requirements may need to be modified depending on the effectiveness of treatment in controlling attacks. Work that requires the operation of dangerous machinery, driving motor vehicles, working at heights, or performing physical labor may be difficult, if not impossible. Individuals may not be able to safely drive to and from work. Duties involving significant social interaction or verbal presentation skills may be in jeopardy if attacks cannot be controlled.

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:

  • Does individual experience excessive daytime drowsiness with recurring episodes of uncontrollable sleep?
  • Do sleep paralysis and vivid hallucinatory dreams occur at sleep onset?
  • Does individual report sudden weakness or loss of muscle tone while awake?
  • Has individual undergone testing at a sleep disorder clinic with electroencephalogram or EEG, electroculogram or EOG, and electromyogram or EMG?
  • Did tests confirm the diagnosis?

Regarding treatment:

  • Were stimulant medications prescribed? Do they help counteract the drowsiness and sleep attacks?
  • Were tricyclic antidepressants prescribed? Do they suppress episodes of cataplexy, hypnagogic hallucinations, and sleep paralysis?
  • Is individual taking medications exactly as prescribed by doctor?
  • Is individual receiving behavior modification in addition to drug therapy? What are results? Does individual participate in a support group?

Regarding prognosis:

  • To what extent do symptoms interfere with daily activities? Does individual have unrealistic expectations concerning abilities or limitations? How old is individual?
  • Does individual perform hazardous activities that could be dangerous to self and others? Can employer make accommodations that will allow individual to work safely?
  • Is individual receiving the appropriate emotional support? Would additional counseling be beneficial?

Source: Medical Disability Advisor



References

Cited

Baker, Matthew J., and Selim R. Benbadis. "Narcolepsy." eMedicine. Eds. Carmel Armon, et al. 4 Oct. 2004. Medscape. 3 Nov. 2004 <http://emedicine.com/neuro/topic522.htm>.

Hayduk, Roza. "Narcolepsy." MedicineNet.com. Ed. Leslie J. Schoenfield. MedicineNet, Inc. 3 Nov. 2004 <http://www.medicinenet.com/narcolepsy/page1.htm>.

Source: Medical Disability Advisor






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