Let’s jump to the conclusions of a recent research report titled Enhanced motivation of cognitive control in Parkinson’s disease! I’ll print the final sentence of the abstract first:
These findings reinforce prior observations that Parkinson’s disease is accompanied by enhanced incentive motivation of cognitive control and highlight the potential of incentive motivational strategies for overcoming cognitive deficits in Parkinson’s disease.
What’s this all about? Let’s look at the first two sentences of the abstract, then dive into the article:
Motor and cognitive deficits in Parkinson’s disease (PD) have been argued to reflect motivational deficits. In prior work, however, we have shown that motivation of cognitive control is paradoxically potentiated rather than impaired in Parkinson’s disease.
In other words, Parkies have a greater interest in cognitive control than non-Parkies, probably because they fear dementia is knock-knock-knockin’ on their noggin. I don’t know about you, but in my case I’ve definitely upped my interest in all things related to cognition and dementia, and striving to keep everything that’s jammed inside my cranium in good working order is now a daily part of my life. Case in point: I’m attempting to read and write about this very article, even though the intended audience is fellow researchers who readily understand all the scientific vocabulary and have probably read the earlier research that this article references.
What did the authors of this study do? They compared three groups of people:
- 22 patients with Parkinson’s as well as a history of depression
- 23 patients with Parkinson’s and no history of depression
- 23 healthy controls (no PD and no history of depression)
The three groups were similar in other ways: age, IQ and gender, for example. Also, both groups of Parkies were alike in how severe their symptoms were and what medications they were on. All Parkies went through the experiment’s tasks twice, once while “on” their meds, and a second time while “off.”
What happened in the experiment? Participants were shown a series of 240 arrows that pointed either to the right or the left. Inside the right-pointing arrows was the word “left,” and inside the left-pointing arrows was the word “right.” At times the participants were told to pay attention to the direction of the arrow, and press a button corresponding to that direction. In other words, if the arrow pointed to the right, they pressed a button on the right. But at other times, the participants were told to ignore the arrow and respond to the word written inside the arrow. So if they saw a right-pointing arrow with the word “left” written in it, they pressed a button on the left.
Furthermore, participants were rewarded if they pressed the correct button. For some tests, the reward was consistently 10 cents. For other tests, the reward was a mere 1 cent.
The researchers looked at reaction times and error rates. They compared whether the PD groups responded differently because they were either “on” their meds or “off,” and they compared the results of all three groups.
One of the main findings was that PD patients typically outperformed the healthy controls, no matter if they were in the depressed or non-depressed group, and no matter if the test was to respond to the words “left” and “right,” or to the arrows pointing left or right. Interestingly, the healthy controls “tended to make more errors on high-reward switch trials compared with low-reward switch trials.” How strange that the healthy controls botched their chance to win big money!
Here’s a paragraph that wraps up the main findings:
In sum, PD patients with and without depression (history) showed reward motivational enhancement of task-switching in terms of error rates, whereas reward motivation, if anything, impaired task-switching in matched healthy controls. We did not observe any differences between PD with and without depression (history) patients and healthy controls in terms of reaction times, and there were no effects of medication [that is, whether the PD participants were on or off their meds].
What’s my take on this? Well, it makes perfect sense that people who know they may lose their marbles sometime in the future have a heightened interest in doing well on cognitive tests now. In a few weeks I’m going to go through a morning of cognitive testing, and I’m already gearing up for it. I’m reviewing my method for counting backwards from 100 by 7’s, and I’m rehearsing how I’ll work on the word problems they may throw at me, such as saying as many words as I can that start with, say, the letter “c.” For example, there’s the “hard c” as in cat, the “soft c” as in ceiling, but also the three “ch’s”: chimney, chef, chemistry. Then there are all the words you can make with the clusters “cl” and “cr”: clown, clothing, cloying, crash, crush, crusty.
Finally, there’s the terrific surprise item, chthonic, which will probably throw the researchers for a loop. (It refers to the spirit world that lives underground in the forest.) Never heard of it? It’s spooky! Here’s a great painting that relates to the chthonic underworld. (Picture and caption are both courtesy of Wikipedia.)
The Remorse of Orestes or Orestes Pursued by the Furies. It depicts the tale from Greek mythology of Orestes being tormented by the Erinyes for murdering his mother Clytemnestra (left), whose lover Aegisthus had killed Orestes’ father Agamemnon. The Erinyes, or Furies, are regarded as chthonic deities – spirits of the underworld.
So I have to agree: Having PD has made me much more interested in cognition than I was before my diagnosis.
