The characteristics of fatigue in PD are:
- It tends to develop early in the disease and, if untreated, gets worse over time.
- It is associated with reduced physical activity and poorer quality of life.
- It can make PD and depression feel worse.
- It is not due to lack of sleep, though it can be associated with sleep problems.
- It often influences mental attention making it harder to concentrate and to focus one’s attention.
- It is unknown at this time if fatigue is more prevalent in men or women.
- One third of PD patients consider fatigue their single most disabling symptom, including the motor symptoms of PD.
- Fifty-eight percent of PD patients consider fatigue one of their three most disabling symptoms
What Is Fatigue in Parkinson's Disease?
Fatigue is typically experienced as a state of being tired, weary, exhausted and without energy. Some people say they feel like they are walking underwater or through molasses—everything is an effort and exhausting. Although fatigue can make depression worse, it is not the same as depression. You can have fatigue and no depression. Most people with fatigue are not necessarily sad or self-destructive.
Similarly, fatigue is not the same as excessive daytime sleepiness. Although fatigue makes daytime sleepiness worse and harder to bear, you can have daytime sleepiness but still not have fatigue. You can experience the need for and urge to sleep and still not feel like you are walking underwater or through a field of molasses! Exhaustion and weariness are not the same as sleepiness.
How Do Doctors Diagnose Your Fatigue?
If you are feeling weary and exhausted all the time and you mention this problem to your doctor, he or she may ask you to fill out a questionnaire to assess your symptoms and he or she may also perform some special tests on you.
- Subjective mental and physical fatigue are evaluated using self-report questionnaires such as the Multidimensional Fatigue Inventory.
- "Physical fatigability" can be measured by observing your endurance levels on physical exercise protocols
- "Mental fatigability" is evaluated by measuring attention over time using a reaction-time paradigm called the Attention Network Test (ANT). In this test you are asked to press a button whenever you see a certain "stimulus" or icon among a group of distractor icons on a computer screen. People with fatigue show a pattern of slowed button presses to certain types of stimuli.
Steps You Can Take to Reduce Fatigue
If you are feeling fatigued and exhausted all the time, what can you do about it? First and most importantly, speak to your doctor about it and tell him how much the fatigue disturbs you. Does it undermine your daily activities? Does it make it more difficult to attend clinic visits or rehabilitation appointments? Does it feed into your emotional life? Does it undermine your coping ability? Once you speak to your doctor about your fatigue, your doctor might also recommend the following:
- Engage in regular physical exercise including use of weights to increase muscle strength. Studies show that physical exercise combats both physical and mental fatigue.
- Anti-depressants. Although fatigue is not caused by depression, depression can worsen fatigue (and vice versa). Treating depression if it is present might allow you to overcome fatigue with exercise or some other treatment.
- A trial of stimulants like methylphenidate or modafinil. Some doctors have reported anti-fatigue properties for these drugs.
Friedman JH, Brown RG, Comella C, Garber CE, Krupp LB, Lou JS, Marsh L, Nail L, Shulman L, Taylor CB; Working Group on Fatigue in Parkinson's Disease. Fatigue in Parkinson's disease: a review. Mov Disord. 2007 Feb 15;22(3):297-308. Review
Lou JS. Physical and mental fatigue in Parkinson's disease: epidemiology, pathophysiology and treatment. Drugs Aging. 2009;26(3):195-208. Review