Parkinson Disease Dementia Symptoms

Cognitive impairment in Parkinson disease may range from a single isolated symptom to severe dementia.

• The appearance of a single cognitive symptom does not mean that dementia will develop.
  
  
• Cognitive symptoms in PD usually appear after physical symptoms.
  
  
• Cognitive symptoms early in the disease suggest dementia with parkinsonian features, a different condition.

Cognitive symptoms in PD include the following:

• Loss of decision-making ability
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• Inflexibility in adapting to changes
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• Disorientation in familiar surroundings
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• Problems learning new material
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• Difficulty concentrating
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• Loss of short- and long-term memory
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• Difficulty putting a sequence of events in correct order
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• Problems using complex language and comprehending others’ complex language

Persons with PD, with or without dementia, respond slowly to questions and requests. They become dependent, fearful, indecisive, and passive. As the disease progresses, they become increasingly dependent on spouses or caregivers.

Major mental disorders are common in PD. Two or more of these may appear together in the same person.

• Depression - Sadness, tearfulness, lethargy, withdrawal, loss of interest in activities once enjoyed, insomnia or sleeping too much, weight gain or loss
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• Anxiety - Excessive worry or fear that disrupts everyday activities or relationships; physical signs such as restlessness or extreme fatigue, muscle tension, sleeping problems
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• Psychosis - Inability to think realistically; symptoms such as hallucinations, delusions (false beliefs not shared by others), paranoia (suspicious and feeling controlled by others), and problems thinking clearly; if severe, behavior seriously disrupted; if milder, behavior bizarre, strange, or suspicious

The combination of depression, dementia, and PD usually means a faster cognitive decline and more severe disability. Hallucinations, delusions, agitation, and manic states can occur as adverse effects of drug treatment of PD.