The standard treatments for Parkinson's disease, which work by increasing dopamine signalling in the brain, can trigger highly risky behaviours, known as 'impulsive-compulsive spectrum behaviours' (ICBs) in approximately 5-10% of patients.
New results, published today in the journal Neuropsychopharmacology, uncover a possible explanation for this behaviour – impaired self-control combined with surprisingly normal motivation. Researchers have shown that Parkinson's patients with ICBs are much more willing to take immediate but smaller benefits rather than waiting for larger ones in the future.
"Some patients end up gambling away their life savings while others run up huge credit card debts. This work sheds light on the reasons behind such behaviours, and may help to treat sufferers of Parkinson's disease in the future," said Charlotte Housden who carried out the work at UCL's Institute of Cognitive Neuroscience, and is now at the University of Cambridge.
Researchers studied a group of 36 Parkinson's disease patients, half of whom had ICBs, and compared them to a group of 20 elderly volunteers without Parkinson's disease. All the participants completed two tests: a computer game that measured motivation, on which the participants attempted to win cash by responding quickly and learning associations between pictures and money; and a questionnaire about financial decisions.
This questionnaire measured a form of impulsivity called "delay discounting", by asking whether someone would prefer receiving a smaller payment quickly, as opposed to waiting for a larger payment. For example, would you prefer to receive £50 today or £80 in a month's time?
The data revealed a clear pattern of results. Against the researchers' expectations, the Parkinson's patients who suffered from ICBs were not more motivated to win money on the computer game than the control volunteers. They were also no better at learning about which stimuli predicted money. On the other hand, they were considerably more likely to choose smaller immediate payments over larger but delayed ones on the questionnaire.
Dr Jonathan Roiser, from the UCL Institute for Cognitive Neuroscience, and supervisor of the study said: "The pattern of more impulsive choices together with intact motivation and learning suggests that ICBs may be mediated by impaired self-control, and not excessive motivation for rewards."
The researchers hope that this study might help in the identification and treatment of ICBs in the future.
Charlotte Housden explained: "Often, when neurologists identify these risky behaviours, their only option is to reduce the dose of drugs which treat the primary symptoms of Parkinson's disease, such as tremor and stiffness. However, this is far from ideal, since an inevitable consequence of this strategy is that these primary symptoms get worse. Our results suggest that treating impulsivity in Parkinson's disease patients with ICBs, for example with drugs used to treat other types of impulsive behaviours, might reduce their risky behaviours without worsening their primary symptoms."
Notes for Editors
1. For more information or to interview Charlotte Housden, please contact Clare Ryan in the UCL Media Relations Office on tel: +44 (0)20 7679 9726, mobile: +44 07747 565 056, out of hours +44 (0)7917 271 364, e-mail: firstname.lastname@example.org.
2. ''Intact Reward Learning but Elevated Delay Discounting inParkinson's Disease Patients With Impulsive-Compulsive Spectrum Behaviors' is published in Neuropsychopharmacology. Journalists can obtain copies of the paper by contacting UCL Media Relations.
Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. UCL is the fourth-ranked university in the 2009 THES-QS World University Rankings. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band Coldplay. UCL currently has over 12,000 undergraduate and 8,000 postgraduate students. Its annual income is over £600 million.
Clare Ryan | EurekAlert!
Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
Foods of the future
15.08.2018 | Georg-August-Universität Göttingen
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology