Psychosis and Dementia in Parkinson s Disease

As the neurodegenerative process that underlies PD progresses, risk for developing psychotic ideation and a dementing illness increase significantly. At least 75 of PD patients who survive for more than 10 years will develop some form of PD dementia (PDD Aarsland & Kurz, 2010), but there is huge variation with some individuals not developing dementia at all, some developing a relatively mild form of dementia, and some not developing dementia until very late in the disease. The mean time from...

Rehabilitation of the Agentic Self

Up to this point in the book, I have described an array of neuropsychiatric disorders that are sometimes seen in PD. However, I do not want to leave the reader with the impression that PD is nothing but a catalogue of deficits. Instead, one of the benefits of looking at PD from the point of view of the agentic self is that we can see that it is a person, an individual, who copes with an array of challenges including functional deficits. The individual is not a syndrome. The person, not the...

Speech and Language Deficits of Parkinson s Disease

I have been arguing that the core cognitive deficit of PD is a weak activation of the agentic self system that is mediated by striatal-DLPFC and frontopolar cortical networks. This failure to fully activate the agentic self leads to hyperactivity in the minimal self system, which is subserved by limbic and orbitofrontal networks. The imbalance of activation between the agentic and the minimal self systems ultimately contributes to the executive control cognitive deficits of PD and the disabling...

The Agentic Self and Personality Changes in Parkinson s Disease

I have been arguing that PD is characterized by weak activation of the neural networks, the striatal-DLPFC frontopolar cortex, that support the agentic self, the self that identifies, values, formulates plans, makes decisions, initiates actions, and acts. Because the dorsal prefrontal systems normally regulate and inhibit ventral, OF, and limbic systems, the weak activation in striatal prefrontal circuits in turn leads to hyperactivity in various limbic, amygdalar, and OF circuits. The...

Impulse Control Disorders in Parkinson s Disease

An impulse control disorder (ICD) occurs when a patient loses control of his impulses around food, sex, money, gambling, and the like. What are the anatomic correlates of ICDs in PD and how does the agentic self fit into the picture of causal factors for ICDs in PD Here is one potential explanation of the anatomic correlates of ICDs in PD The agentic self system is in mutual inhibitory balance with the minimal self system. Anatomically, when the dorsal PFC-basal ganglia loop is impaired, the...

The Neurology of the Agentic Self

Cognitive Operations of the Agentic Self We have seen that the agentic self identifies values to be striven after, then makes decisions about which values goals to pursue and then controls pursuit of those goals. Two important cognitive processes that contribute to a sense of agency or agentic control are decision-making processes and goal pursuit or action selection and control. I will have a lot to say about these two major components of the agentic self. But, in this chapter, I want to break...

On Parkinson s Disease

This book presents a theory concerning certain symptoms associated with the major neuropsychiatrie disorders of Parkinson's disease (PD). We will, therefore, need to present the basics of PD for readers not familiar with the condition. PD is a progressive neurodegenerative disorder that most commonly strikes people over 60 years of age. The mean duration of the disease is approximately 13 years, and the mean age at death is approximately 73. Its cardinal clinical manifestations are four major...

References

W. (2010). The epidemiology of dementia associated with Parkinson disease. Journal of the Neurological Sciences, 289(1-2), 18-22. Aarsland, D., Larsen, J. P., Lim, N. G., Janvin, C., Karlsen, K., Tandberg, E., et al. (1999). Range of neuropsychiatric disturbances in patients with Parkinson's disease. Journal of Neurology, Neurosurgery, and Psychiatry, 67, 492-496. Aarsland, D., Litvan, I., Galasko, D., Wentzel-Larsen, T., & Larsen, J. P. (2003). Performance on the...