There are some general properties shared by all forms of electromagnetic radiation: 1  It can travel through empty space. 2  The speed of light is constant in space. 3  A wavelength of light is defined similarly to that of water waves---distance between crests or between troughs.
The Parkinson Handbook Fatigue and Parkinsonâs Disease. Fatigue due to Depression-Depression is common in people with Parkinson's disease. It occurs in about 40% of the patients. Fatigue is a typical symptom of depression and is often reported as a lack of motivation or a loss of energy.
If so, youâre not alone. Chronic fatigue accounts for more than 10 million visits to family doctors every year. Chronic fatigue has many causes, including illnesses such as anemia and multiple sclerosis as well as depression and other psychiatric disorders.