Can There Be Cognitive Impairments in Parkinson's disease (PD)? Yes
Updated: Oct 25, 2019
There are several types of movement disorders and each one has anatomical and physiological characteristics that present with distinct cognitive and behavioral symptoms. Neuropsychological impairment has also been associated with multiple movement disorders and may present as either an early symptom or later in the course of the neurodegenerative process.
Parkinson’s disease (PD) is one of the most common movement disorders. Parkinson’s disease and other types of parkinsonism are common movement disorders that share motor, cognitive and behavioral symptoms, but which must be distinguished due to different prognoses and responses to treatment.
Parkinson’s disease (PD) affects approximately 350 per 100,000 individuals. Approximately 95% of incident cases of PD occur after the age of 60 making it a common disorder among the elderly. It is characterized by motor symptoms including slowness of movement and difficulty initiating movement, masked facies, muscular rigidity, shuffling or unsteady gait, stooped posture, disturbances in equilibrium, and tremor.
Behavioral and neuropsychological disorders are common in PD and other parkinsonian syndromes. Depression is the most common psychiatric syndrome in PD; anxiety and apathy are also frequently observed.
Neuropsychologically, there can be cognitive deficits found in many non-demented PD patients, and the prevalence of neuropsychological deficits increases with disease duration. In patients with PD that are exhibiting deficits in cognitive abilities, in many cases, these deficits are typically confined to specific functions such as loss of cognitive flexibility, reduced ability for learning and recall of information, and psychomotor slowing.
In non-demented PD patients, they may experience neuropsychologic deficits that can include moderate impairment in verbal and nonverbal memory for both immediate and delayed recall. Language functions are generally spared. Visuospatial and visuo-constructive skills are among the most frequently cited deficits in PD, even when the effects of motor slowing are taken into account. Executive functions are the earliest and most consistently impaired abilities.
In demented PD patients, the common neuropsychological features of Parkinson’s Disease Dementia (PD-D) include bradyphrenia (slowness of thought) and deficits in attention/executive functions, memory (particularly poor retrieval), language (micrographia, hypophonia, poor semantic and phonemic verbal fluency), and impaired visuo-constructional/visuoperceptual functions.
Neurodegenerative disorders that share clinical similarities with PD include DLB (Lewy Body Disease), PSP (Progressive Supranuclear Palsy), CBGD (Corticobasal Degeneration), HD (Huntington’s Disease), and the various subtypes of MSA (Multiple System Atrophy). Parkinson’s plus syndromes often exhibit subtle differences in symptom onset and/or severity that assist in differential diagnosis. Essential tremor is associated with action tremor, often without significant neuropsychological dysfunction.
While approximately 50 percent of people with PD will experience some form of cognitive impairment, not all will lead to a dementia diagnosis. Sometimes the cognitive symptoms are best characterized as a mild cognitive impairment (MCI). MCI often does not significantly interfere with home and work life. In the past, the medical team used to believe that cognitive changes in PD did not develop until mid- to late-stage PD, but recent research suggests that mild changes may be present at the time of diagnosis.
Tell your doctor if you have concerns about cognitive changes. You may need to change your medication or you may benefit from a neuropsychologist for assessment to objectively document your current cognitive abilities.
If you live in the New Jersey or New York area and would like to schedule a neuropsychological evaluation for yourself or a family member in order to determine if there have been any potential cognitive changes related to PD or other movement disorders please contact Dr. Corey Burchette at 201-577-8286 to inquire about scheduling an appointment at the New Jersey Memory Center which is located in Verona, New Jersey.