Mood and Memory Changes in Parkinson's Disease

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Most people with Parkinson’s disease notice some decline in their memory and mental agility, even very early in the course of the disease. Chances are that your PD will also affect your thinking to some extent. But the effects are subtle.

For example, you may notice that it takes you a bit longer to retrieve a memory, come to a decision, calculate a cost or plan a trip. This overall mental sluggishness is influenced by your mood and, in turn, can sometimes negatively influence your mood as well.

The good news is that new research has begun in the area of cognitive rehabilitation that can very effectively reverse this mental sluggishness.

The Profile of Memory and Cognitive Changes in Parkinson’s Disease

People with PD even the very early stages of PD have difficulty with their thinking processes. Most authorities agree that the primary difficulty lies with the so-called ‘executive cognitive functions'. Executive cognitive functions refer to such thinking processes as memory retrieval, planning, generation of words or concepts, attention, and monitoring and adjustment of non-routine and goal-directed behaviors. The common denominator in all of these executive functions is that they require cognitive control in order to operate smoothly. The term ‘cognitive’ refers to processes or operations involved in processing of all kinds of information. So cognitive control processes are those processes that are used by the mind and brain to regulate the storage, retrieval and usage of information (thinking).

Problems with executive functions are typically mild in early PD. They usually involve a generalized slowing of cognitive processing speed (bradyphrenia) and subtle deficits in attention and working memory. It may be difficult, for example, to hold two different pieces of information in the mind at the same time, or to efficiently generate words and concepts as quickly as one used to.

As the disease progresses, these executive cognitive deficits are made more severe by mood and emotional problems such as depression and anxiety.

Effects of Memory and Cognitive Changes of Parkinson’s Disease

While it may seem clear to you that emotional states can have a significant impact on your thinking, the reverse is also true: Your thinking can sometimes strongly influence your emotional states. You know the proverbial story of two men who see the same glass of water but one sees it as half full and the other as half empty? The same goes for thinking and emotional states.

Sometimes your assessment of a situation can influence your emotional reaction to that situation. More generally, executive cognitive functions can influence your mood states because those executive functions control all the information you have about the situations you find yourself in. Executive functions control your ‘appraisal’ of those situations. If you find it difficult to recall happy memories, you may become more sad or depressed.

If you find it difficult to plan a vacation, you may put off the vacation and thus influence your mood states and so forth.

Problems with executive functions can also get you into trouble over serious matters like money. If you find it difficult to balance the checkbook, you may get a bit sloppier about your finances. Consider also that the extra jolt of dopamine that comes from taking dopamine medications can sometimes make you temporarily more energized and impulsive. Now when you couple a heightened sense of impulsivity with a lowered capacity for thinking efficiently through decisions, you sometimes get ‘impulsive responding’ -- bad decisions.

One final problem with executive functions is that it impacts the caregiver. Many studies have shown that it is more difficult to care for someone who is having difficulties with executive functions than it is to care for someone without cognitive problems.

For all these reasons, it is important to take the memory/cognitive problems that you might have seriously. They may seem minor annoyances, but they can pack a wallop over time. There is no sense letting them go unattended, particularly when there are effective remedies on the horizon -- and indeed, there are such remedies.


Mathias, J.L. (2003). Neurobehavioral functioning of persons with Parkinson’s disease. Applied Neuropsychology, 10(2), 57-68.

Sammer, G., Reuter, I., Hullmann, K., Kaps, M., & Vaitl, D. (2006). Training of executive functions in Parkinson’s disease. Journal of the Neurological Sciences, 248(1-2), 115-119.

Sinforiani, E., Banchieri, L., Zucchella, C., Pacchetti, C., & Sandrini, G. (2004). Cognitive rehabilitation in Parkinson’s disease. Archives of Gerontology & Geriatrics, Suppl. 9, 387-391.

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