skip navigation
Welcome! Orthopedics Resources Neurology Resources #PTDOS Physical Therapy Pulse Contributors Store

Huntington's Disease

Huntington's Disease Overview

 

 

 

 

Population Characteristics:1,2

  • Prevalence of Huntington's disease (HD) is 2.71 per 100,000 worldwide
  • Higher prevalences in Europe, North America, and Australia (5.7 per 100,000) than compared to Asia (.4 per 100,000)
  • Worldwide incidence of .38 per 100,000 per year
  • Symptoms of HD typically begin between the ages of 30 and 50 years but can be present as early as 2 years of age

Pathophysiology:1,3

  • Genetic disorder caused by the repeated expansion of the CAG DNA segment within the huntingtin gene
    • Average CAG segment length in normal individuals is 16 to 20 repeats
    • In HD, the CAG segment length is typically 36 repeats or more
    • While the certain mechanism is unkown, alterations in the huntingtin gene causes neural degeneration of the striatum and then progresses to atrophy of the cerebral cortex and subcortical structures 

Signs and Symptoms:4

  • Chorea of the fingers, feet, face, and/or trunk
    • As disease course progresses, chorea becomes more widespread and frequent and begins to affect performance of functional mobility 
  • Decreased balance and coordination, unsteady gait, increase in falls
  • Slurred speech, difficulty with eating and swallowing
  • Decreased cognition (impaired memory and judgment, difficulty with multi-tasking, disorientation)
  • Hypotonia paried with hyperreflexia

Diagnosis:4

  • Diagnosis is based upon genetic testing in terms of quantifying amount of CAG repeats
    •  28  or less CAG repeats: Normal range
    • 29-34 CAG repeats: Individual will not develop HD but offspring are at a greater risk
    • 35-39 CAG repeats: Some will develop HD, offspring at a greater risk
    • 40 or greater repeats: Individual will develop HD
  • CT and MRI scanning can also be used in conjunction with genetic testing to assess brain atrophy to assist in diagnosis

Prognosis:2,5

  • There currently is no cure for HD
  • HD is a progressive disorder that results in slow and steady deterioration of cognitive and motor function
  • Average lifespan is 10-20 years after intial onset of symptoms
  • Cause of death is normally not directly related to HD and rather is a result of infections, choking, or pneumonia 

Physical Therapy Interventions:6,7

Early-Stage HD:

  • Postural education
  • Strengthening of neck extensors, trunk stabilizers, and intrinsic hand/feet mm's
  • Balance and proximal stability training
  • Aerobic exercise for cardiovascular/endurance maintenance

Mid-Stage HD:

  • Equipment training (wheelchair fitting, assistive device training)
  • Bed mobility, transfer, transitional movement, and gait training
  • Continued balance and fall prevention strategies
  • Continued strengthening of postural musculature
  • Tone management

End-Stage HD:

  • Continued equipment training as necessary
  • Caregiver training
  • Pressure relief techniques
  • Continued transfer/gait/endurance/strength/balance training as tolerable

 

 

References

1. Pringsheim T, Wiltshire K, Day L, et al. The incidence and prevalence of Huntington's disease: A systematic review and meta-analysis. Movement Disorders. 2012;27(9): 1083-1091. 

2. What is Huntington's disease (HD)? Huntington's Disease Society of American Web site. 2014. Available at http://www.hdsa.org/about/our-mission/what-is-hd.html. Accessed March 30, 2014. 

3. Huntington's disease. Johns Hopkins Pathology Web site. 2010. Available at: http://pathology.jhu.edu/department/divisions/neuropathology/research-huntingtons.cfm. Accessed March 30, 2014. 

4. Huntington's disease: Hope through research. National Institute of Neurological Disorders and Stroke Web site. 2013. Available at: http://www.ninds.nih.gov/disorders/huntington/detail_huntington.htm. Accessed March 30, 2014. 

5. Dorsey ER, Beck CA, Darwin K, et al. Natural history of Huntington disease. JAMA Neurol. 2013;70(12): 1520-1530.

6. Quinn L and Busse M. Physiotherapy clinical guidelines for Huntington's disease. Neurodegen Dis Manage. 2012;2(1): 21-31. 

7. Imbirglio S. Physical and occupational therapy: Huntington's disease. Huntington's Disease Scoeity of America Web site. Available at: http://www.hdsa.org/images/content/1/1/11697.pdf. Accessed April 24, 2014.