Access to the latest research — for scientists and people living with PD alike — in PDF's new scientific journal.
Fatigue in Early Parkinsonís Disease
- Mar 08 2012
People with newly diagnosed Parkinson’s disease (PD) frequently experience fatigue that interferes with their daily activities and may contribute to depression, according to a study in the February 16 issue of the European Journal of Neurology. These findings suggest that people with early PD should be screened for and educated about this under-recognized symptom.
Fatigue is a common symptom of many diseases and even affects people without an identifiable illness. It is different than sleepiness; instead it is a feeling of being extremely tired, of being either physically or mentally weary. Doctors had previously noticed that some people with PD complain of fatigue, but they didn’t know how prevalent or severe the symptom was in people with PD compared to healthy controls, or when during the course of PD fatigue arises. So researchers led by Karen Herlofson, M.D., Ph.D., at the Sorlandet Hospital in Arendal, Norway studied the presence and severity of fatigue in people at the time of PD diagnosis, before the individuals began any dopaminergic treatment.
The team evaluated 199 people with untreated, newly diagnosed PD and 172 control subjects matched for gender and age. Participants lived in Western and Southern Norway and were part of a larger study of newly diagnosed PD known as the Norwegian ParkWest project. Dr. Herlofson and colleagues asked the study participants to rate their fatigue using a questionnaire called the Fatigue Severity Scale. The researchers also investigated whether fatigue correlates with symptoms such as depression, cognitive impairment, daytime sleepiness, and apathy.
- 55 percent of the people with PD experienced fatigue, compared with about 20 percent of the controls
- People with PD were more likely to have severe fatigue than were controls
- People with fatigue were more likely to be depressed and less able to perform daily activities
- Fatigue did not correlate with cognitive impairment, sleepiness, or apathy
What Does It Mean?
These results suggest that fatigue is a common problem in people with early PD, and the symptom can manifest before the disease is even diagnosed. Depending on the person, fatigue in PD may be nonexistent, a minor inconvenience, or a major distress. Fatigue interfered with people’s activities of daily living. People with fatigue and PD were also more likely to have symptoms of depression.
Although scientists do not yet know the cause of fatigue in PD, the finding that fatigue occurs early in the course of the disease indicates that fatigue does not result from PD medications or from an extensive cell death. Further research is needed to determine how fatigue arises in PD, and how best to treat it. Currently, there are no effective treatments for fatigue. A few clinical trials assessing whether medications that are used for other causes of fatigue (e.g., jet lag) may be helpful for PD were inconclusive. Therefore, the Movement Disorders Society Evidence Based Medicine treatment review considers such treatments (including modafinil and methylphenidate) “investigational” (http://www.ncbi.nlm.nih.gov/pubmed/22021174).
This study has several strengths compared with others that have investigated fatigue in PD. The study population was relatively large and representative: 75 percent of people who were newly diagnosed with PD in four western and southern counties of Norway participated. Dr. Herlofson and colleagues included a control group of healthy individuals, which is important because fatigue is a relatively common complaint in the general population.
Nonetheless, fatigue is highly subjective and therefore difficult to study. Differing perceptions of fatigue may have influenced the study’s results. Also, cultural factors can influence people’s perceptions and descriptions of fatigue, so the study should be repeated in other populations. In sum, this study confirms that fatigue is a significant concern in PD, and treatments for fatigue in PD, therefore should be further investigated.
If you would like to know more about this topic, view the recording of PDF's online seminar, "Fatigue, Sleep Disorders and Parkinson's," led by Joseph Friedman, M.D.
Reference: Herlofson, K., Ongre, S. O., Enger, L. K., Tysnes, O. B., & Larsen, J. P. (2012). Fatigue in early Parkinson's disease. Minor inconvenience or major distress? European Journal of Neurology. doi:10.1111/j.1468-1331.2012.03663.x
Source Date: Mar 08 2012