Potential Pathologic Processes Underlying Cognitive Domain Impairments
While the attention and frontal-executive functions appear to be the predominant cognitive domains affected in PD, it is clear from the previous sections that the pattern of cognitive domain impairments in PD is complex. In fact, some PD patients exhibit relatively isolated impairments in memory, while others in frontal-executive or visual-spatial function . This suggests that the neuropathologic substrates of cognitive impairment in PD may also be variable. Studies on the neuropathologic basis of CI in PD are still somewhat limited.
The contribution of other pathologic changes to CI in PD is unclear. Vascular disease is an important primary and co-contributing cause of dementia in the elderly . Unfortunately, there is little to no data on the presence of vascular pathology in PD, and its influence on CI. Recent evidence has linked the presence of TDP-43 pathologic change to Lewy body disorders . However, the clinical significance of this pathology, typically linked to frontotemporal dementia and amyotrophic lateral sclerosis, has not been determined.
Clinical Algorithm: Assessment Of Mild Cognitive Impairment
This is a single-page, quick-reference algorithm to help clinicians assess mild cognitive impairment in a person with Parkinsons. Derived by multidisciplinary consensus and to address gaps in current clinical guidelines, it is designed to be printed and kept conveniently to hand in the consultation room. The evidence underpinning the algorithm is presented as an accompanying series of Critically Appraised Topics .
The algorithm is not designed to be applied rigidly, but to be used as an optional starting point for decision making around this complex element of care. Individual clinicians and people affected by Parkinsons may need to tailor their approach depending on their particular experience and values.;
What Is Normal Cognitive Aging And How Does Pd Fit In
Many people attribute cognitive changes to aging, and a major concern expressed by people with PD and their care partners is whether cognitive deficits are related to aging or to PD. Cognitive changes in people with PD need to be benchmarked against normative data and age-related changes. Cognitive decline without dementia can occur in aging, perhaps because neuropathological processes such as neuronal loss, deposition of amyloid, tau, and -synuclein, and vascular changes, often found post-mortem, are common as we age. The progression of cognitive decline is a key element in attributing changes to underlying disease-related processes. In general, cognitive changes in normal aging should not interfere significantly with everyday activities that require cognitive abilities. If they do, however, this may suggest an abnormal process and signal an increased risk of developing MCI or dementia. Changes in functional abilities and everyday activities due to cognitive decline can be difficult to identify if they are mild. Distinguishing whether problems in everyday activities are due to cognitive or motor problems in PD, or a combination of both, can be challenging, and appropriate measures for determining this are needed.
Recommended Reading: Parkinson’s Life Expectancy After Diagnosis
What Is Parkinson’s Disease Dementia
Parkinson’s disease is an age-related degenerative disorder of certain brain cells. It mainly affects movements of the body, but other problems, including dementia, may occur. It is not considered a hereditary disease, although a genetic link has been identified in a small number of families.
- The most common symptoms of Parkinson’s disease are tremor of the hands, arms, jaw, and face; rigidity of the trunk and limbs; slowness of movement; and loss of balance and coordination.
- Other symptoms include shuffling, speaking difficulties, , facial masking , swallowing problems, and stooped posture.
- The symptoms worsen gradually over years.
Depression, anxiety, personality and behavior changes, sleep disturbances, and sexual problems are commonly associated with Parkinson’s disease. In many cases, Parkinson’s disease does not affect a person’s ability to think, reason, learn, or remember .
About 500,000 people in the United States have Parkinson’s disease, and about 50,000 new cases are diagnosed each year. The number of those who have some cognitive symptoms is difficult to pinpoint because accurate data are lacking for the following reasons:
Most people have the first symptoms of Parkinson’s disease after the age of 60 years, but Parkinson’s disease also affects younger people. Early-onset Parkinson’s disease strikes people around the age of 40 years, or even earlier.
What Is Needed For A Parkinson’s Disease Dementia Diagnosis
There is no definitive medical test that confirms cognitive decline or dementia in Parkinson’s disease. The most accurate way to measure cognitive decline is through neuropsychological testing.
- The testing involves answering questions and performing tasks that have been carefully designed for this purpose. It is carried out by a specialist in this kind of testing.
- Neuropsychological testing addresses the individual’s appearance, mood, anxiety level, and experience of delusions or hallucinations.
- It assesses cognitive abilities such as memory, attention, orientation to time and place, use of language, and abilities to carry out various tasks and follow instructions.
- Reasoning, abstract thinking, and problem solving are tested.
- Neuropsychological testing gives a more accurate diagnosis of the problems and thus can help in treatment planning.
- The tests are repeated periodically to see how well treatment is working and check for new problems.
Imaging studies: Generally, brain scans such as CT scan and MRI are of little use in diagnosing dementia in people with Parkinson’s disease. Positron emission tomographic scan may help distinguish dementia from depression and similar conditions in Parkinson’s disease.
Recommended Reading: Can Gabapentin Cause Parkinson’s
How Common Is Cognitive Decline In Parkinsons
A new study finds that;cognitive;impairment is a frequent and rapidly progressing symptom of Parkinsons disease . About half of the participants who had PD for an average of five years and had normal cognition at the beginning of the study developed mild cognitive impairment within six years about 11 years after PD diagnosis. Those few who developed MCI progressed to;dementia within five more years. The results appear in the September 11 online edition of;Neurology.
With a diagnosis of PD, most people and their physicians focus on treating and coping with movement symptoms. Yet even early in the course of disease, people with PD may have difficulty multitasking, or feel that their thinking abilities are just not the same.
To better understand the rate at which cognitive impairment develops, and identify risk factors for the development of cognitive impairment, researchers led by Daniel Weintraub, M.D., recruited 141 people with PD to participate in the study. All were receiving treatment at the University of Pennsylvanias Udall Center for Parkinsons Disease Research. On average they were 69 years old and had been living with PD for five years; 63 percent were men. All participants had normal cognition based on a battery of standard tests for people with PD. The researchers re-evaluated study participants cognition each year for up to six years.
What Does It Mean?
Clinical Measures Of Cognition In Pd
Determining objective changes in cognitive function frequently involves neuropsychological testing. Test selection may depend on a number of factors such as age, education, and language. Test performance can be affected by motor function as well as physiological changes of aging . Therefore, neuropsychological testing in PD should include some measures that do not rely on manual dexterity or motor speed as these can be compromised and make it difficult to separate motor symptomatology from a given cognitive ability.
Many tests of global cognition have been studied or reviewed in PD, including the Mini-Mental State Examination, Montreal Cognitive Assessment , PD-Cognitive Rating Scale, Addenbrookes Cognitive Examination, among others.,,, Many tests covering different cognitive domains also have been used in PD. The Movement Disorder Society Task Forces for PDD and PD-MCI diagnostic criteria provide recommendations for assessments of cognitive domains and neuropsychological tests., Standardized protocols and PD-specific neuropsychological batteries may provide uniformity across multiple centers and research trials.
Read Also: Does Parkinson’s Make You Tired
What Are The Complications Of Parkinson Disease
Parkinson disease causes physical symptoms at first. Problems with cognitive function, including forgetfulness and trouble with concentration, may arise later. As the disease gets worse with time, many people develop dementia. This can cause profound memory loss and makes it hard to maintain relationships.
Parkinson disease dementia can cause problems with:
- Speaking and communicating with others
- Problem solving
- Paying attention
If you have Parkinson disease and dementia, in time, you likely won’t be able to live by yourself. Dementia affects your ability to care of yourself, even if you can still physically do daily tasks.
Experts don’t understand how or why dementia often occurs with Parkinson disease. Its clear, though, that dementia and problems with cognitive function are linked to changes in the brain that cause problems with movement. As with Parkinson disease, dementia occurs when nerve cells degenerate, leading to chemical changes in the brain. Parkinson disease dementia may be treated with medicines also used to treat Alzheimer’s disease, another type of dementia.
What Are The Symptoms Of Parkinson’s Disease Dementia
Cognitive impairment in Parkinson’s 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 Parkinson’s disease usually appear years after physical symptoms are noted.
- Cognitive symptoms early in the disease suggest dementia with Parkinsonian features, a somewhat different condition.
Cognitive symptoms in Parkinson’s disease include the following:
- Loss of decision-making ability
- Loss of short- and long-term memory
- Difficulty putting a sequence of events in correct order
- Problems using complex language and comprehending others’ complex language
Persons with Parkinson’s disease, with or without dementia, may often respond slowly to questions and requests. They may become dependent, fearful, indecisive, and passive. As the disease progresses, many people with Parkinson’s disease may become increasingly dependent on spouses or caregivers.
Major mental disorders are common in Parkinson’s disease. Two or more of these may appear together in the same person.
The combination of depression, dementia, and Parkinson’s disease 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 Parkinson’s disease, this might complicate the diagnosis of Parkinson’s dementia.
Recommended Reading: Stimulants And Parkinson’s Disease
What Are The Parkinson’s Disease Dementia Criteria
Many people with Parkinson’s disease experience cognitive changes , but not all of them develop full-blown dementia. So at what point does Parkinson’s disease cause dementia?
On average, Parkinson’s disease dementia happens about 10 years after a person first starts having movement problems.
“It happens many, many years after someone has developed Parkinson’s,”Lynda Nwabuobi, MD, assistant professor of clinical neurology at Weill Cornell Parkinson’s Disease and Movement Disorders Institute, tells Health. “It can be around 10 to 15 years.”
In fact, if someone shows signs of dementia early on in their Parkinson’s diagnosis , it could be that they were misdiagnosed out of the gate. “They might have dementia with Lewy bodies,” Dr. Nwabuobi explains.
Timing is the main factor in Lewy body dementia versus Parkinson’s disease dementia. While the two can look very similar, the dementia symptoms occur before motor symptoms in Lewy body dementia, and in Parkinson’s disease the reverse is true.;
“If you look at the brain, it’s difficult to distinguish them,” Dr. Litvan says. “But clinically, they are different.”
Dealing With Dementia In Pd
In this 1-hour webinar movement disorder specialist, Dr. Jennifer Goldman, provides an overview of clinical symptoms and current research on the risks for and causes of dementia in PD. ;She discusses treatment and management strategies, along with practical tips and resources for people with Parkinsons and care partners dealing with dementia in PD.
Read Also: Can Parkinson’s Run In The Family
The Era Of Digital Cognitive Testing
The development of digital cognitive testing and the evolution of self-completed computerized assessments and wearable devices to assess cognitive functioning in daily life, provides an exciting opportunity to both improve clinical management and to obtain more sensitive outcome measures for clinical trials and will likely become a standard procedure in the future, given further technological improvements and increased access to the internet and digital devices. To reach this point, psychometric requirements , documentation and technical problems, as well as their relation to traditional tests, need to be well known.
Causes Of Cognitive Impairment In Pd
The exact causes of cognitive impairment or dementia in Parkinsons disease are not fully understood. There may be changes in the neurochemical signals that the brain uses to pass along information to different regions of the brain. Besides dopamine, the neurochemical signals acetylcholine, serotonin, and norepinephrine are especially important for cognition, memory, attention, and mood. In autopsy studies, Lewy bodies, abnormal protein accumulations, have been found in neurons in brain regions responsible for cognitive processes. Other causes include co-existing strokes or mini-strokes or Alzheimers disease pathology.
Recommended Reading: Parkinson’s Disease Epidemiology
Box 1 Movement Disorder Society Pd
Level I Abbreviated assessment
Impairment on Parkinson disease -appropriate global cognitive ability scale , Parkinsons Disease Cognitive Rating Scale , Mattis Dementia Rating Scale Second Edition )
Impairment on at least two neuropsychological tests when a limited set of tests is used
Level II Comprehensive assessment
Neuropsychological testing includes two tests per domain:
Attention and working memory
Impairment on two tests in one domain or impairment on one test in two different domains
Impairment shown by:
Score 12SD below norm
Significant decline on serial testing
Significant decline from estimated premorbid functioning
PD with mild cognitive impairment subtype classification
Single domain: impairment on two or more tests in one domain
Multiple domain: impairment on at least one test in each of two or more domains
Parkinson disease dementia
In dementia trials in PD, other rating scales have been used to assess the degree of cognitive impairment, its effect on activities of daily living and the clinical global impression of change, although none of them have been specifically designed nor recommended for PDD. These include the Alzheimers Disease Assessment Scale Cognitive Subscale , the Alzheimers Disease Cooperative Study Activities of Daily Living Scale and the Alzheimers Disease Cooperative Study Clinical Global Impression of Change , all of which have been developed in the context of dementia due to AD.
Ask The Md: Cognitive Impairment And Parkinsons Disease
This 4:27-minute video is an explanation of cognitive changes that can happen in Parkinsons disease. ;Dr. Rachel Dolhun explains how doctors evaluate cognitive changes to exclude other conditions that may be correctable. ;She distinguishes between mild cognitive impairment and dementia, with some treatments for each.
Recommended Reading: What Is The Life Expectancy Of Someone With Parkinson’s Disease
Genetics Of Pd Dementia
Although the genetic risk factors for PD have been investigated, much less is known about the genetic factors associated with the development of dementia in PD. According to some studies, the prevalence of PDD is lower in patients with genetic PD. However, this will depend on the gene variant and other comorbidities that predispose the development of cognitive disorders. Some of the most important genes are discussed below:
PARK1: patients with duplication or triplication of alpha-synuclein gene have more severe motor progression and worse cognitive prognosis compared to those without the mutation. Although the evidence suggests that the higher the number of replications, the lower the age of onset of cognitive impairment. Of all genes, this seems to be the most related to dementia. More studies are needed to confirm these findings .
PARK2: according to some case series, mutations in PARK2 do not seem to cause cognitive decline .
PARK14: PLA2G6 mutation could show heterogeneous phenotype including dementia.
DJ-1: due to its low prevalence, there is no clear relationship between DJ-1 and a particular PD cognitive phenotype. There are some reports of dementia within the clinical spectrum of DJ-1 mutations. In a large population-based survey, there was no evidence for an increased risk of dementia in carriers of DJ-1 deletion .
PINK1: due to its low prevalence, there is conflictive evidence on the relation between PINK1 and PD dementia or cognitive decline .
What Causes Parkinson Disease
Parkinson disease arises from decreased dopamine production in the brain. The absence of dopamine makes it hard for the brain to coordinate muscle movements. Low dopamine also contributes to mood and cognitive problems later in the course of the disease. Experts don’t know what triggers the development of Parkinson disease most of the time. Early onset Parkinson disease is often inherited and is the result of certain gene defects.
Recommended Reading: Life Expectancy Of Parkinson’s Patients
Language Dysfunction In Parkinsons
There are several functions within language, including naming objects, generating words, comprehension, and verbal concepts. PD most often affects a persons 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
Box 2 Diagnostic Procedure Movement Disorder Society Pdd Criteria8144
Level I Parkinson disease dementia
A diagnosis of Parkinson disease based on the UK Brain Bank criteria for PD
PD developed prior to the onset of dementia
Mini-Mental State Examination below 26
Cognitive deficits severe enough to impact daily living independent of motor symptoms
Impairment in more than one cognitive domain, that is, at least two of the following aspects:
Months Reversed or Seven Backward
Lexical Fluency or Clock Drawing
Absence of other abnormalities that obscure diagnosis
Level II Comprehensive assessment for characterizing PDD
The level II evaluation assesses four domains:
Computerized cognitive testing
Digital computerized cognitive testing, which can be carried out remotely from patients homes, has become an interesting alternative to traditional pen-and-paper testing. Benefits of computerized testing include the opportunity for frequent testing with less learning effects, which increases the sensitivity to detect decline, cost-efficiency and the availability of large normative databases. Opportunities for conducting both remote functional assessments and digital interventions on the same online platform are being studied,.
You May Like: How Is The Family Of A Person With Parkinson’s Affected