Parkinson’s Cognitive Problems versus Other Neurological Diseases

14 February 2015

Carole A. Mazurowski, PhDHealth Psychology & Neuropsychology6565 Americas Parkway NE, Suite 200,

Albuquerque, NM505-620-2848

Main Parkinsonian Syndromes

• Primary (idiopathic) Parkinson's disease– Tremor-predominant– Bradykinetic primary

• Secondary (acquired, symptomatic) parkinsonism • Pugilistic encephalopathy • Normal pressure hydrocephalus • Multiple system degenerations (parkinsonism plus) • Progressive supranuclear palsy • Shy-Drager syndrome• Striatonigral degeneration • Corticobasat ganglionic degeneration • Lewy body disease

Basic Neuropsychology

• Brain organization has areas for movement and thinking spread in adjoining or overlapping chunks all over.

• Parkinson’s arises from loss of dopamine in the substantia nigra of the brain.

• Approximately 80% of substantia nigra cells are usually destroyed before motor symptoms appear.

• PD often also involves losses in other subcortical areas of the brain.

More Neuropsychology• The substantia nigra is part of the

basal ganglia in the middle part of the brain with neural tracts extending into frontal lobes.

• Changes do not show in CT or MRIs

• Diagnosis is through Presenting symptoms

Dementia Rates in PD

• The percentage of PD patients to experience a dementia ranges has been estimated between 20% to 40%

• Incidence rate increases with age. A recent longitudinal study showed that by 85 years of age more than 65% of its PD participants had dementia. Another study found about 75% developed dementia 8 years into illness.

Movement, Mood & Thinking

• The basal ganglia has been best known as the area where movement disorders originated – originally it was thought PD did not affect cognition

• Current research shows the basal ganglia governs starting and stopping thoughts and actions as well as modulating mood and cognition

Dementia in PD

• Dementia diagnosis requires memory deficits plus at least one other cognitive deficit that significantly interferes with daily functioning

• Most Parkinson’s patients eventually experience some cognitive decline, though it does not qualify as a dementia syndrome

Alzheimer’s BrainNote the rampant atrophy with particular focus on memory &

language areas

PD versus Alzheimer’s

• In Alzheimer’s Disease one of first signs is a rapid decay of memory that does not respond to cueing.

• Although PD patients may experience memory difficulties, there is a greater ability to recall information with cues or multiple choices.

• Like a house of cards collapsing, problems with organizing and paying attention can impact ability to remember.

FRONTOTEMPORAL DEMENTIA

Atrophy of frontal and temporal (near the ears) brain areas

• Some lose language early in the illness• Others decline in social interpersonal

conduct• Impairment in regulation of personal

conduct• Emotional blunting• Loss of insight

Procedural Memory Problems

• As the corpus striatum, a part of the basal ganglia, contributes to the procedural memory system, PD patients whose disease has affected that area may have trouble with learning new skills and response patterns to novel situations

• By contrast, procedural memory is usually spared in Alzheimer’s disease: playing favorite piano tunes, for example.

Slowed Mental Processing

• This may be greater for individuals with the more slowed type of PD, called bradykinetic, versus tremor-predominant

• Contributes to inability to start into action and conversations

Executive Functioning Problems

• Difficulty developing successful problem-solving strategies

• Impaired set-shifting – getting stuck on one idea when a new one is needed

• Difficulty maintaining correct sequencing• Poor use of feedback from others• Poor use of internal cues to guide behavior• Difficulty holding back irrelevant responses• Poor initiation – starting an action or thought

process• Impulsivity – starting into action quickly

without thinking• Inability to allocate attention where needed• Poor concept formation, particularly when

the ideas are abstract

Delirium

• Due to the PD brain’s greater struggles with mental processing, risk is high for delirium for a few days after general anesthesia

• If there is a sudden decline in memory and thinking, consult your physician to check current medications or for an infectious process such as urinary tract infection

• Dehydration is a common cause of delirium

• Kidney malfunction can cause Amantadine buildup leading to delirium

Lewy Body Dementia• A progressive dementia caused by

abnormal protein deposits (Lewy bodies) depleting dopamine

• PD also has Lewy bodies, but not as abundantly as in LBD, where they also occur throughout the brain

• In LBD the cognitive decline begins at about the same time as Parkinsonian symptoms start occurring

• Cognitive deficits are similar to PD, but progressing faster and including more visuospatial difficulties

• Visual hallucinations early in illness

Confusion• Patients without dementia sometimes

mention rare occurrences of sudden periods of confusion

• PD meds can make dreams more lifelike, causing confusion with sudden awakening

• Awakening away from home can cause confusion before the patient reorients

• Dementia patients often experience more confusion towards the evening – known as sundowning

• Naps can be helpful to decrease confusion

Depression & Cognition

• There is a much higher rate of depression in PD than most other neurological disorders – multiple sclerosis, for example.

• In an older individual without neurological disorders, depression itself can cause what looks like a dementia.