Fatigue and dementia
Feeling tired, unmotivated, or less sharp
About half of people with Parkinson's disease complain of fatigue. Some feel sleepy, whereas others report low energy or an exhaustion that levels them. Doctors will explore to what extent the symptoms result from depression or sleep problems; addressing those disorders may relieve the fatigue. Exercise may also help, so Friedman encourages patients to slowly work up to a regular walking routine of 30 minutes a day. If fatigue still persists, he sometimes prescribes stimulants.
As Parkinson's disease becomes an ever-greater obstacle to everyday routines, roughly 40 percent of patients exhibit apathy. They lose interest and joy in the hobbies or activities that used to bring them pleasure, and they seem indifferent to the friends, family, and events around them. They stop caring about anything.This can be upsetting to see in a patient, especially because it seems as if he's giving up on treatment and on life. Then again, apathy may protect him from distress and frustration over his growing disability, Friedman points out. Apathy may be related to depression, dementia, or sleep disorders, so addressing those conditions may help. Generally, however, there's no good cure for apathy.
Most people with Parkinson's disease will at some point experience mild cognitive changes that may hinder attention, memory, mental processing speed, problem-solving, processing of visual information, and the ability to pull the right words from one's vocabulary. In many cases, patients compensate for these subtle deficits without much detriment to life at work or home.
Showing signs of dementia
Severe impairment of memory and thinking, along with confusion and disorientation, may develop with dementia, the worst of the nonmotor Parkinson's symptoms. It can render the patient incapable of taking on daily activities of living. Although research studies vary widely on the numbers, experts generally estimate that 30 percent of Parkinson's patients suffer from dementia.
Usually, dementia arises in later stages of Parkinson's. If major cognitive trouble arises early, another illness is likely to blame, such as Alzheimer's disease or a Parkinson-like disorder called dementia with Lewy bodies (which actually looks similar to very late-stage Parkinson's dementia).
The dementia of Parkinson's disease is somewhat different from that of Alzheimer's, although there are similarities, says Friedman. Alzheimer's patients don't record new memories and wouldn't remember a grocery list of five items. People with Parkinson's dementia would store the memory of the items but may not recall them until you give hints or cues. Patients struggle more with language and forgetting of words and names in Alzheimer's than in Parkinson's. On the other hand, Parkinson's dementia patients are, earlier on, "very bad at judging spatial relationships between objects, which can be a problem with their driving," Friedman says. "They have trouble organizing, they have trouble multitasking."
The Alzheimer's drug Exelon (rivastigmine) was federally approved for treating dementia in Parkinson's in 2006, but its benefits are relatively modest, says Friedman. The same appears true of other Alzheimer's drugs in the same category, called cholinesterase inhibitors.