?Parkinson: what is apathy
Apathy is a very debilitating syndrome present in many patients with Parkinson's disease. More than a loss of motivation, it is also the decline in cognitive abilities that dissuades people from getting moving, explains Dr Matthieu Béreau, neurologist at Besançon University Hospital.
Very common in neurodegenerative diseases, apathy is characterized by a loss of motivation in people who suffer from it. In neuropsychiatry, it is defined as a reduction in goal-directed behaviors. Around 30% of patients with Parkinson's disease are affected.
The motivational and cognitive dimension of apathy
Apathy is actually a multidimensional syndrome. “It’s not just a story of motivation but also of cognition. To take an action you have to want to do it and adopt an appropriate strategy,” summarizes Dr Matthieu Béreau, neurologist at Besançon University Hospital and member of the LINC laboratory (Laboratory for Integrative Research in Neuroscience and Cognitive Psychology), located in the same city.
With other researchers, he painted a clinical picture of apathy in a review article published in the journal Cells, showing the importance of cognition in decision-making. “Let’s take the example of a person who wants to go for a walk in the forest in a place where they have never been before. She will need a certain mental flexibility to adopt appropriate behavior outside of her usual routine. This therefore implies being able to mobilize cognitive capacities,” illustrates the neurologist. With cognitive dysfunction, it is much more difficult to plan and execute actions, thus worsening the lack of motivation already present.
How to notice the appearance of apathy? It can be detected in people of an active nature, who gradually abandon their favorite activities. Also comes strong procrastination and an almost systematic lack of will. The patient's lack of initiative can greatly disturb the caregiver, who is obliged to push him to undertake activities so that he does not fall into isolation. On the other hand, apathy is not necessarily synonymous with sadness, although it can be part of a neuropsychiatric triad with depression and anxiety. “In depression, there is a sadness of mood, which is not found in apathetic patients. When we question them, they do not say they are sad but tired,” underlines Dr Matthieu Béreau.
Apathy as a warning sign
Apathy would only be the tip of the iceberg, because the associated symptoms can manifest well before the motor problems linked to Parkinson's disease, characterized by the akinesia-rigidity-tremor triad. Loss of desire and abandonment of certain activities can occur a few months or even a few years before the appearance of motor symptoms. “I saw a patient who previously played tennis very regularly but who ended up stopping due to lack of desire. He came for a consultation for tremors but he had been experiencing symptoms related to apathy for over a year,” says the neurologist. Although apathy should be monitored as a warning sign of neurodegenerative diseases, it must also be considered for its intrinsic impact on the quality of life of patients and those around them.
The role of dopamine
Dopamine is a neurotransmitter involved in movement but also in motivation. However, Parkinson's disease is characterized by the death of dopaminergic neurons, leading to dysfunction of motor and motivational circuits, which are interrelated. “When dopamine correctly modulates motor circuits, our movements are harmonious and fluid, which allows us to not have to think about what we are doing. For patients with Parkinson’s disease, behavior no longer becomes automatic but adaptive, that is to say, they are forced to think about their actions,” explains Dr. Matthieu Béreau. Enough to further tire patients already suffering from apathy.
?What are the treatments considered
If at the start of Parkinson's disease, the deficit is mainly motivational, it also ends up being cognitive: it is the apathy of decline, heralding a decline towards dementia. “Pure” motivational apathy can be treated with medications that boost the production of dopamine. The question is whether this treatment could at the same time delay the onset of cognitive apathy.
Between motor and neuropsychiatric problems which vary depending on the stage of progression of the disease and depending on the individual, recent research tends to show that there may not be Parkinson's disease but Parkinson's diseases! This is what members of the neuroscience laboratory in Besançon, including Dr Matthieu Béreau, will explore through the study of apathy.
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