Cognitive changes such as dementia are common in Parkinson’s disease. For most of us “dementia” is a very scary word, so I’d like to make clear that although such a cognitive impairment is common, not all those with Parkinson’s necessarily experience dementia. Parkinson’s disease dementia is less likely in early onset disease, tremor onset patients, and where significant depression is absent. However, because patients with Parkinson’s disease are about six times more likely to suffer from dementia than those without Parkinson’s, it is a good idea to pay close attention and watch for signs of dementia, as some medical treatment may be needed. Therefore, a clear understanding of what “dementia” is will follow.

What Dementia Is:
Dementia is a disturbance in intellectual function that interferes greatly with essential aspects of life and progressively worsens over time. The typical profile of Parkinson’s disease dementia consists of:

declining ability to reason,

slowed mental processing,

dramatic lapses in memory,

worsening visual-spatial construction

and trouble maintaining attention.

The various types of dementias that can occur in patients with Parkinson’s may overlap and co-occur, making them hard to distinguish. Neurological exams and neuropsychological assessments may help pinpoint and ascertain the different dementias. Conventional segmentation has divided dementia into two types: cortical and subcortical. Cortical dementia is typically found with Alzheimer’s disease and characterized by profound memory problems early on. Subcortical dementia is a slowing of cognitive processing, forgetfulness, apathy, and retrieval difficulties early on.

When watching for signs of Parkinson’s disease dementia, it is appropriate to worry, but try not to become alarmed. Cognitive changes do not automatically suggest the onset of dementia. If you are suspicious of certain behaviors, consult your neurologist for a neuropsychological consultation. It is painless, detailed, and can uncover factors that may be the cause of cognitive changes.