Fatigue is one of the most common symptoms experienced by people with Parkinson’s. Various studies have indicated that at least 50% of people with Parkinson’s are affected by fatigue, and it is frequently one of the most disabling symptoms.
Fatigue does not correlate with the severity of Parkinson’s, or how long a person has had the condition. But it does correlate with Depression, and depression itself invariably causes fatigue. However, in Parkinson’s the effective treatment of depression often does not relieve fatigue. As such, for people with Parkinson’s, fatigue and depression are considered independent of each other.
Although fatigue tends to be a neglected Parkinson’s symptom, with few studies on this aspect of the condition, there are two significant, long-term reports:
One study1 observed people with Parkinson’s over nine years and found that the majority of those who experienced fatigue at their first assessment still had it at the end of the nine year period. By contrast, the study showed that those who were not fatigued at their first assessment were unlikely to become fatigued later. The study also revealed that fatigue tended to be persistent and often worsened over time in people who experienced the symptom in the early stages of their Parkinson’s.
In another study2, 230 people with Parkinson’s were observed for eight years, and it was found that the fatigue became more prevalent over that period, with 36% affected initially, 43% after five years, and 56% after eight years. The people who experienced fatigue generally complained of persistent fatigue, but at least 44% said that fatigue fluctuated or varied over time.
Doctors often describe more than one type of fatigue in Parkinson’s:
- muscle or Peripheral fatigue - the loss of strength with repeated muscle contraction or activity. This type of fatigue is frequently reported as a sense of weakness, and probably earned the disease its original name “paralysis agitans” (‘paralysis’ referring to weakness and ‘agitans’ referring to the associated Tremor). Muscle fatigue is usually called ‘peripheral fatigue’ by specialists and some studies have shown that people with Parkinson’s who experience it noticed an improvement when taking Levodopa or other Dopaminergic medications
- central fatigue - this involves an inability to cope with physical and mental tasks which require self motivation. This type of fatigue does not seem to respond as well to levodopa and dopaminergic medications as peripheral fatigue
- mental fatigue – a difficulty in initiating and sustaining mental tasks of any type
- physical fatigue – a difficulty in carrying out physical activities.
The effect of fatigue on quality of life is usually clear to see:
- mental and physical fatigue can affect psychological and emotional wellbeing
- the person who is fatigued may become less active and unable to pursue hobbies and interests
- social activity requires energy, so a person with fatigue will have a greater tendency to become withdrawn
- a reduced inclination to engage in activities is likely to bring with it reduced stamina, reduced fitness and further muscle weakness.
For all these reasons it is important for people with fatigue to try and keep as active as possible. One leading Neurologist advises that anyone newly diagnosed with Parkinson’s that they have no restrictions and should encourage their relatives to prevent them from becoming less active to reduce the risk of experiencing fatigue and other symptoms.