Parkinson’s Disease Dementia: Two related diseases

Parkinson’s disease dementia. Both are words that, when alone, provoke a sense of dismay. Together, they can be catastrophic without a capable medical team and strong family support. Parkinson’s disease dementia is a series of cognitive deficits secondary to Parkinson’s disease. I have witnessed the effects firsthand in my grandfather. Thus, I seek to bring awareness to Parkinson’s disease dementia and its causes, symptoms, and management tips.

Parkinson's Disease Dementia

Parkinson’s Disease Dementia

What is Parkinson’s Disease?

Parkinson’s Disease is a progressive disorder of the central nervous system. The disease process breaks down the dopamine-producing nerve cells (neurons) in the substantia nigra, which is part of the brain responsible for reward and movement. Dopamine is a neurotransmitter crucial for proper motor function. As its levels fall, the lack of dopamine leads to disabling motor symptoms including tremors, rigid muscles, loss of movements, bradykinesia, speech difficulties, and more.

What is Dementia?

Dementia is defined as a decline in cognitive function that affects a person’s daily life. Cognitive function entails thinking, remembering, reasoning, or behavior, and dementia interferes with activities requiring attention, memory, visual perception, problem-solving, and self-management. Personality changes and an inability to control emotions are marked signs of dementia.

How Does Parkinson’s Disease Cause Dementia?

There are numerous types of dementia characterized by the specific changes occurring within the brain. However, Parkinson’s disease dementia is a form of dementia secondary to Parkinson’s disease. Professionals do not fully understand the connection between the two conditions. They assume that alterations in chemistry and structure of the brain associated with Parkinson’s disease result in the cognitive impairments.

CAB Test/ Cognitive Test

General Cognitive Assessment Battery from CogniFit: Study brain function and complete a comprehensive online screening. Precisely evaluate a wide range of abilities and detect cognitive well-being (high-moderate-low). Identify strengths and weaknesses in the areas of memory, concentration/attention, executive functions, planning, and coordination.

Risk Factors for Developing Parkinson’s Disease Dementia

According to the Alzheimer’s Association, 50 to 80 percent of Parkinson’s disease patients progress to develop Parkinson’s disease dementia. Not all will be diagnosed with Parkinson’s dementia, but the chances increase if the following factors apply to you or your loved one with Parkinson’s:

  • Older age at Parkinson’s onset
  • A family history of dementia
  • Advanced stage or longer duration of Parkinson’s
  • Being a Male
  • Visual hallucinations
  • Severe motor symptoms

Symptoms of Parkinson’s Disease Dementia

Parkinson’s disease dementia differs from dementias like Alzheimer’s because the effects are primarily centered around skills of problem-solving (executive function) rather than language and memory. Still, the cognitive symptoms present in a variety of categories as thinking speed slows with the disease progression.

Problem Solving (Executive Function)

Executive functions are skills that allow us to identify a goal and to achieve that goal through problem-solving. It involves the functions of planning, organization, and self-regulation. Those with Parkinson’s Disease Dementia are hit hard in this area of goal-directed behavior.

While lacking in executive functioning, they struggle to carry out simple tasks. Multi-tasking and switching from one idea to the next become difficult. Imagine the inability to go from making breakfast to brushing your teeth, or not speaking up in a conversation because you cannot convey your thoughts with a rapid change in subject from the weather to current politics. Part of the reason why Parkinson’s Disease Dementia is debilitating is that executive functioning is at the center of every facet of life.


Trouble focusing and feeling scatterbrained or “spaced out” are the symptoms of Parkinson’s Disease Dementia under the umbrella of attention. Without factoring in issues with problem-solving, Parkinson’s dementia prevents the blocking out of external stimuli. Attention on a single stimulus is challenging. For example, simultaneously walking and talking is a huge feat as dementia possess the patient’s attention span.


Memory is not as affected in Parkinson’s disease dementia as it is in Alzheimer’s, but patients should expect mild deficits. There are multiple types of memory characterized by the events they describe. Symptoms correlated with memory loss occur in the later stages of Parkinson’s disease.

Parkinson's Disease Dementia

Parkinson’s Disease Dementia Long-term Memory Deficits

Immediate and Short Term Memory

Immediate memory lasts seconds to minutes, while short-term memory spans minutes to days. Parkinson’s dementia impairs both. The inability to recall events that just happened and names of people recently met are symptoms of short-term memory impairment. Remembering to take medications on time is another potential repercussion of short-term memory loss.

Working Memory

Working memory involves storing information and “working” with that information over a short period. Arithmetic is a working memory function. Calculating finances and telling time are the first functions of working memory to go. Symptoms stem from impairments in reading comprehension, participating in conversation without forgetting what to say, and remembering directions for tasks (i.e. rules to a game, school lessons, etc.).

Long-term Memory

Long-term memory comprises memory over days to years. Long-term memory deficits are the most distressing, as the information previously known for years is suddenly forgotten. Declarative memory, a type of long-term memory for facts, concepts, and events is particularly compromised in Parkinson’s dementia. After declarative memory, patients show a decline in procedural memory—the long-term memory for performing tasks. Tasks learned at a young age like how to tie a shoe, read a book, or ride a bike are confused as Parkinson’s dementia progresses.

Mood and Psych

Illness, in general, has unfavorable consequences on mood. Parkinson’s dementia exceeds the typical moodiness of not feeling well. The cognitive impairment transforms mood and personality in numerous ways.

Depression and Anxiety

Depression is consistent sadness persisting for 2 weeks or more. Studies prove up to 40 percent of Parkinson’s patients are depressed (Anderson, 2004). Aside from depression, anxiety disorders are common. Generalized anxiety, social phobia, obsessive-compulsive disorder, and panic attacks are serious enough to interfere with daily functioning. The progression of depression and anxiety tends to occur after the onset of motor symptoms. There is evidence to believe depression and anxiety are rooted in neuropathology from a chemical imbalance of dopamine.


Psychosis is a mental disorder in which the state of mind is disrupted to where emotions and perceptions are out of touch with reality.

The patient is typically unaware of their behavior. Although it is less common in Parkinson’s dementia, delusions and hallucinations arise from psychosis. Hallucinations are false appearances of people, animals, or objects that are not truly there. Delusions are explained to be incorrect beliefs contrary to the patient’s normal thinking. While sometimes amusing to the patient, hallucinations and delusions are distressing symptoms for caregivers to witness. It is important to understand that these changes are the disease and not you or your loved one with Parkinson’s.


Parkinson’s disease directly causes reduced tone and volume while speaking, slurred speech, a hoarse voice, and swallowing difficulties. These physical manifestations are only compounded with the effects on language from Parkinson’s dementia.

“Um, huh, I…” Finding the right words with Parkinson’s dementia is a prominent symptom. Failing to name objects, decreased comprehension, and incorrectly interpreting language are signs of the condition.

Visuospatial Skills 

Visuospatial deficits are common in Parkinson’s disease dementia. A healthy body and mind visually take in the surrounding environment and automatically determines spatial relationships. In Parkinson’s dementia, however, visual input is not judged appropriately. Patients struggle to use mental imagery like using their imagination to draw shapes or copy images formed in their minds. Sense of direction is hindered too. Following and giving explicit directions, completing a puzzle, recognizing dangers, and driving visuospatial skills that regress in Parkinson’s dementia.

Visuospatial perception is strongly connected with motor symptoms and coordination. It is what tells the brain about the environment and alters sense of direction. “Transient motor blocks” called freezing are triggered by the misperception of visual input like “approaching an obstacle in the path or entering narrow spaces such as doorways” (Giladi, 2001).

Contributors to Parkinson’s Disease Dementia

While not the cause of Parkinson’s disease, lifestyle factors contribute to the progression of dementia. Whether permanent or a brief flare, the following can exacerbate dementia symptoms.

B12 Deficiency

B12 is an essential vitamin found in animal products and fortified foods. It is required for red blood cell production, DNA synthesis, and neurological function. A deficiency of B12 causes neuropathy and cognitive deficits for the average person, which is only increased tenfold in the case of Parkinson’s disease. Current research proves that B12 levels decrease in Parkinson’s disease, so it is imperative to ensure enough of the nutrient is absorbed to avoid detrimental effects on the nervous system.


Acute infection is known to worsen Parkinson’s dementia. This can occur with systemic infections, as well as urinary tract infections and pneumonia. The infection causes hallucinations and delusions to become more prominent, but symptom exacerbation resolves once the infection is treated with antibiotics.

Dopamine Agonists and Anticholinergics

Levodopa, dopamine agonists, MAO-B inhibitors are common medications used in the treatment of Parkinson’s disease. Despite the obvious benefits these drugs have on motor symptoms, some patients notice the deterioration of cognitive abilities if Parkinson’s disease dementia is present. Side effects are drowsiness, unclear thinking, and hallucinations—all contributing to comparable symptoms from dementia. Slightly decreasing the doses are enough to minimize dementia progression, yet remaining therapeutic for the motor symptoms of the disease.

Poor Sleeping Patterns

Sleep disturbances are a symptom of Parkinson’s disease with or without Parkinson’s dementia. They are:

  • Insomnia
  • Excessive daytime drowsiness
  • REM sleep disorder
  • Restless leg syndrome
  • Nightmares
  • Sleep apnea

Patients with Parkinson’s dementia have worsened cognitive impairments correlated with poor sleeping patterns. With a marked reduction in sleep, the mind is foggier. Practicing good sleep hygiene is key to eliminating poor sleep as a dementia trigger. Sleep hygiene means limiting daytime naps, avoiding stimulants and heavy foods before bed, and establishing a relaxing environment that promotes rest.

Managing Parkinson’s Disease Dementia

Much like its underlying condition, Parkinson’s disease dementia has no cure. Patients must discover what therapies, medications, and lifestyle adjustments are successful for relieving their symptoms in combination with removing unfavorable lifestyle factors.

Caregiver Monitoring for Parkinson’s Patients

Delusions, hallucinations, and fluctuating moods leave those with Parkinson’s Disease Dementia agitated. When symptoms severely impact daily functioning, a caregiver is often necessary to prevent the dementia patient from harming themselves and others.

Aside from assisting with the basics of eating, hygiene, and medication safety, a caregiver’s focus is to keep the patient calm. Creating and sticking to a routine reduces confusion. Caregivers should maintain an even tone of voice when communicating, display love and affection, monitor the patient’s living space and lessen visual misperceptions by providing nightlights during sleep.

Medications to Treat Parkinson’s Dementia

The medical community resorts to pharmaceutical options for treating the motor symptoms of Parkinson’s disease. Regardless of the scientific advancements, medications for the cognitive deficits of Parkinson’s disease dementia are limited.

Cholinesterase Inhibitors

The go-to medications for treating Alzheimer’s disease are cholinesterase inhibitors, but the class of drugs is found to improve memory problems in Parkinson’s disease dementia. Cholinesterase inhibitors block the breakdown of the neurotransmitter acetylcholine. In addition to dopamine, Parkinson’s disease dementia decreases the levels of acetylcholine too.

Examples of cholinesterase inhibitors are Galantamine (Razadyne), Rivastigmine (Exelon), and Donepezil (Aricept). Side effects like weight loss, headaches, insomnia, fatigue, frequent urination, and hypertension are generally mild.


As previously mentioned, depression and anxiety are two symptoms of Parkinson’s disease dementia that are debilitating. Antidepressants are prescribed to treat depression and anxiety.

Selective serotonin reuptake inhibitors (SSRIs) is the preferred class of antidepressants for Parkinson’s dementia. Citalopram (Celexa) and sertraline (Zoloft) are two examples of common SSRIs. Side effects consist of dry mouth, nausea, loss of appetite, drowsiness, blurred vision, and tremors.


Physicians should heed caution when prescribing antipsychotics in patients with Parkinson’s dementia. Antipsychotics target the behavioral symptoms, as well as hallucinations, but side effects are potentially dangerous in 50 percent of patients.

Side effects may include sudden changes in consciousness, impaired swallowing, acute confusion, episodes of delusions or hallucinations, or appearance or worsening of Parkinson’s symptoms.


Benzodiazepines are a class of psychoactive medications that exhibit great effects in reducing anxiety and even quelling episodes of significant agitation in Parkinson’s disease. Clonazepam (Klonopin), diazepam (Valium), and alprazolam (Xanax) are Benzodiazepines used in Parkinson’s.  These medications work on neurotransmitter levels. Parkinson’s disease dementia patients should not take them frequently, as they have the likelihood of increasing dementia symptoms with a side effect profile impacting cognition.

Brain Exercises for Parkinson’s Disease Dementia

Mental exercise is helpful for Parkinson’s dementia patients in that it is proven to slow progression. An active mind builds brain cells. Over time, people with dementia accumulate a reserve of brain cells to counteract cell destruction from the disease. Activities that stimulate the brain to enhance function in areas of memory, reasoning, and processing speed.

  • Puzzles
  • Games
  • Reading
  • Dancing
  • Knitting
  • Yoga
  • Music
  • Journaling
  • Crossword

Brain games are highly beneficial.

Physical Therapy

Exercise is needed to maintain muscle tone, which is why many patients already attend physical therapy. A physical therapist tailors an exercise program to the individual based on an evaluation. Physical exercise is just as crucial to managing Parkinson’s dementia as mental exercise. Exercises release endorphins and stimulate neurotransmitters to facilitate brain cell growth. As more neurotransmitters become available, Parkinson’s dementia symptoms such as mood and memory problems are reduced. For the best outcome, the standard recommendation for Parkinson’s patients is 30-40 minute increments of exercise 4-5 times a week.


Parkinson’s disease dementia is difficult to handle emotionally. Psychotherapy, also referred to as “talk-therapy.” is designed to help the patient cope with the emotional challenges of the condition. Professionals are prepared to treat any secondary mental disorders (i.e. depression, anxiety, psychosis) and are schooled in approaches to enhance cognitive function. Psychotherapy techniques include relaxation, exposure to anxiety sources, and group counseling for encouraging healthy relationships.


Anderson, K. E. (2004). Behavioral disturbances in Parkinson’s disease. Dialogues in clinical neuroscience, 6(3), 323-32.

Giladi, N. Gait disturbances in advanced stages of Parkinson’s disease Advances in Neurology, 86 (2001), pp. 273-278.

National Institute on Aging. (2017). What is dementia? Retrieved from

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