Unawareness of movement disorders in Parkinson's Disease

The concept of awareness of illness refers to the ability that people have in recognizing their disturbances. The presence of a possible unawareness of illness is well described in different clinical pathologies. The awareness of deficits may be sometimes altered in patients suffering from Parkinson’s disease (PD). In order to have a greater clinical utility, theoretical models of unawareness, should allow for the possibility of integrating neurobiological and neuropsychological levels of explanation and should comprehend convergent analyses of these levels. With the aim of integrating such levels of explanations, a series of variables of interest will be considered from a convergent perspective at the neurobiological, neuropsychological and psychological-psychiatric levels. In particular, this chapter will focus on a specific analysis of awareness of movement disorders in non-demented patients with PD and motor fluctuations. So far, only one study has analyzed differences in the awareness of deficits in PD patients by comparing the On and Off states using an extensive battery of cognitive and behavioral functioning [Amanzio et al., 2010]. The results of this study demonstrated that PD patients have a selective reduced awareness of dyskinesias when in the On state, while being aware of their hypokinesias in the Off state. Interestingly, such a reduced awareness of dyskinesia-related movement disorders was associated with executive functions in the On state. In contrast, no association with executive functions was found in the Off state. We believe that this study together with more in depth analysis of the phenomenon of unawareness of deficits may add important elements to the literature on neuropsychological impairments observed in unaware - non-demented patients with PD - in terms of executive dysfunctions. Besides, such elements may significantly contribute to the management of this particular class of pathology. Our explanatory hypothesis is that the disruption of prefrontal-subcortical connections may cause impaired insight, independently of cognitive deterioration. Our model will also critically discuss the role that motivation may have in the unawareness of symptoms in the On medication state.