Summary: A new study sheds light on why some people with Parkinson’s disease binge eat. Researchers report working memory impairment and alterations in reward sensitivity could be behind why binge eating can be problematic in those with Parkinson’s.
The results of a new study conducted by Damiano Terenzi, Raffaella Rumiati and Marilena Aiello of SISSA (Scuola Internazionale Superiore di Studi Avanzati), in association with the doctors of Azienda Ospedaliera Universitaria Ospedali Riuniti di Trieste, show that “binge eating”, which affects some Parkinson patients, may be associated with working memory impairment. This deficit can cause the patients to gorge themselves, since it prevents them keeping in memory the long-term goal of a healthy eating behaviour. A fault in this mechanism had already been associated with eating disorders which typically affects adolescents.
In the study, published in Parkinsonism and Related Disorders journal, the authors also investigated reward sensitivity and its components such as liking (the pleasure connected with the consumption of food) and wanting (the desire to obtain food).
“Binge eating may affect different Parkinson patients as a side effect of dopaminergic drugs which they need to take” explain Damiano Terenzi and Marilena Aiello, respectively first author and coordinator of the research. “In literature, impulse control disorders, such as hypersexuality or gambling, have often been described in Parkinson’s disease and associated to an alteration of working memory and of reward sensitivity. On binge eating, it has never been investigated. This is the first survey ever to be conducted on this specific problem”.
A problem with the reward mechanism
The researchers began by analysing reward sensitivity to understand if it was altered in Parkinson patients with binge eating problems.
Reward sensitivity comprises two components: the first is “liking” and it is associated with the pleasure a specific action gives; in this case eating. The second is “wanting”, namely the drive to search for the experience of pleasure and repeat it.
To measure the first component, the authors used an affective priming task, in which the participants were asked to classify as positive or negative a stimulus (or rather an emoticon), preceded by foods presented subliminally, that is, without being visible to the participants. If the food possesses a positive value for the participant, they were expected to be quicker at classifying positive stimuli and vice versa if the food possesses a negative value.
To assess the second component, the authors presented images of foods and asked participants how much they craved them by exerting pressure on a hand-grip dynamometer. In this task, the effort exerted by the participant is considered to be directly associated to his motivation for the reward.
Terenzi and Aiello explain: “Our study showed that the patients with Parkinson disease affected by binge eating give a negative value to sweet foods compared to the participants not affected by the disease, probably because this category of foods is very problematic for them, but they do not exhibit an increased desire for the same category of foods”.
But there’s more. The presence of binge eating is associated with a working memory deficit.
The origin of binge eating
Working memory is a function that allows us to keep information in mind while we are carrying out an action. We may speculate that due to a working memory deficit, Parkinson patients suffering from binge eating may be unable to stop gorging themselves and to think about the possible effects of their behaviour.
The authors conclude: “This study gives precise indications about the mechanisms that are altered in binge eating in Parkinson patients. It is a first and important step to understanding its origins. Other surveys must be conducted to confirm and explore this evidence regarding a behaviour which not only heavily affects thequality of life of patients but also exposes them to serious long-term consequences for their health, such as weight gain and related diseases”.
Source: Donato Ramani – SISSA
Publisher: Organized by NeuroscienceNews.com.
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Original Research: Abstract for “Reward sensitivity in Parkinson’s patients with binge eating” by Damiano Terenzi, Raffaella I. Rumiati, Mauro Catalan, Lucia Antonutti, Giovanni Furlanis, Paolo Garlasco, Paola Polverino, Claudio Bertolotti, Paolo Manganotti, and Marilena Aiello in Parkinsonism and Related Disorders. Published March 8 2018.
Reward sensitivity in Parkinson’s patients with binge eating
Parkinson’s disease (PD) patients who are treated with dopamine replacement therapy are at risk of developing impulse control disorders (ICDs) (such as gambling, binge eating, and others). According to recent evidence, compulsive reward seeking in ICDs may arise from an excessive attribution of incentive salience (or ‘wanting’) to rewards.
In this study, we tested this hypothesis in patients with PD who developed binge eating (BE).
Patients with BE, patients without BE, and healthy controls performed different experimental tasks assessing food liking and wanting. Participants first rated the degree of liking and wanting for different foods using explicit self-report measures. They then performed an affective priming task that measured participants’ affective reactions towards foods (liking), and a grip-force task that assessed their motivation for food rewards (wanting). All participants also completed several questionnaires assessing impulsivity, reward sensitivity, anxiety and depression, and underwent a neuropsychological evaluation.
Patients with BE displayed an altered liking for sweet foods compared to controls but not to patients without BE. Furthermore, this difference emerged only when implicit measures were used. Importantly, an increased wanting was not associated with binge eating even if wanting, but not liking scores significantly correlated with LED levodopa, confirming the hypothesis of a distinction between the two components of rewards. Lastly, binge eating was associated with depression and lower working memory scores.
Take together these results suggest that binge eating in PD is associated with cognitive abnormalities, and to lesser extent affective abnormalities, but not with an increased incentive salience.