Symptoms – Cognitive Changes

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Changes to cognition – the ability to think or mentally process – is a common non-motor symptom of Parkinson’s disease (PD). Cognitive changes may be slight or severe, and cognitive impairments can cause significant disability and burden for both the patient and the caregiver. Cognitive impairments are associated with an increase in nursing home placement, caregiver distress, and mortality.1

Cognitive impairments from PD include memory difficulties, slowed thinking, confusion, and dementia. Changes to cognition may appear as distractibility, disorganization, forgetfulness, or difficulty solving problems. Cognitive changes can occur even in the earliest stages of PD. One study found that cognitive impairments were present in 19% of patients with PD at the time of diagnosis. Cognitive changes seem to worsen as PD progresses. Dementia is prevalent in approximately 30% of all people with PD, and 80% of people with PD will develop dementia in their disease progression. It is not known exactly how PD causes cognitive impairments, although the disease’s effects on dopamine and other neurotransmitters (chemical messengers) as well as the development of Lewy bodies (accumulations of the protein alpha-synuclein) are believed to be involved.2-4

Executive dysfunction in Parkinson’s disease

Executive functions in cognition are higher-order mental processes, including the ability to plan, organize, initiate and regulate behavior to meet goals. Executive functioning is present in activities such as multitasking, switching tasks, and solving problems. The prefrontal cortex of the brain and the dopamine system are responsible for executive function. As PD damages these areas, executive dysfunction occurs, and executive dysfunction is one of the most common cognitive impairments found in people with PD.3,4

Memory difficulties in Parkinson’s disease

The most common difficulty for people with PD is remembering information that has previously been learned. Memory has several different processes and types, and people with PD have trouble recalling information but their long-term memory function generally remains intact. Memory cues or choices can help people with PD to retrieve information from the brain’s long-term storage.3,4

Attention difficulties in Parkinson’s disease

Attention involves filtering information, and people with PD who experience attention difficulties have trouble maintaining focus, especially as the complexity of a situation increases. Attention difficulties can affect both intellectual pursuits and everyday activities, such as walking and holding a conversation at the same time.1,3

Slowed thinking in Parkinson’s disease

Slowed thinking or processing, also known as bradyphrenia, affects how people with PD can process and respond to information. Slowed thinking affects other cognitive abilities, such as problem-solving, as well as daily activities like carrying on a conversation.3

Language dysfunction in Parkinson’s disease

There are several functions within language, including naming objects, generating words, comprehension, and verbal concepts. PD most often affects a person’s ability to find a word, although as PD progresses, additional language difficulties may develop, including difficulty naming, difficulty comprehending information, and the use of more simplified and less spontaneous speech.3,4

Visual-spatial dysfunction in Parkinson’s disease

Visual-spatial (or visuospatial) abilities provide a map of the environment and involve the sense of direction. Dysfunction in visual-spatial abilities causes difficulties in perceiving, processing, discriminating, and acting on visual information around the person. People with PD who experience visual-spatial dysfunction may have difficulty navigating around their home, reaching for objects, or avoiding obstacles in their path.3,4

Dementia in Parkinson’s disease

Dementia is defined as problems in more than one cognitive area, and the cognitive problems cause significant impairment in everyday functioning. Dementia in PD is more common with advanced disease, usually developing many years after the initial onset of the disease. Patients who develop dementia before or at the same time of PD motor symptoms are usually given the diagnosis of dementia with Lewy bodies. However, many experts believe both PD with dementia and dementia with Lewy bodies are related disorders that fall under Lewy body disorders.4

Management of cognitive impairments in Parkinson’s disease

After a thorough evaluation to rule out other causes of cognitive impairment, patients with PD may be treated with medication, occupational therapy, and/or speech therapy. The medications used to treat cognitive impairments in people with PD are based on treatments used for Alzheimer’s disease. Currently, the only medication that is approved by the Food and Drug Administration (FDA) for use in people with PD with dementia is Exelon® (rivastigmine). Occupational therapy can help a person with PD by providing adaptive strategies for daily activities. Speech therapy can help with language functions, as well as information processing. 3,4

view references
  1. Watson GS, Leverenz JB. Profile of cognitive impairment in Parkinson disease. Brain Pathol. 2010 May; 20(3): 640–645.
  2. Accessed online on 1/9/17 at http://www.medscape.com/viewarticle/734227_5.
  3. Parkinson’s Disease Foundation. Accessed online on 1/9/17 at http://www.pdf.org/en/winter07_08_Not_Just_a_Movement.
  4. American Parkinson Disease Association. Accessed online on 1/9/17 at http://www.apdaparkinson.org/cognitive-issues-in-parkinsons-disease/.
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View Written By | Review Date
Written by: Emily Downward | Last reviewed: March 2017
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