© Cambridge University Press 2013. Parkinson's disease (PD) is characterized by progressive degeneration of the nigrostriatal dopaminergic system and other subcortical neuronal systems leading to striatal dopamine deficiency and other biochemical deficits related to the variable clinical signs and symptoms of the disorder . Resting tremor, slowness of initial movement, rigidity, and general postural instability are mainly associated with the loss of dopaminergic neurons in the substantia nigra pars compacta, leading to reduced dopaminergic input to the striatum [2,3]. Besides motor symptoms, cognitive disturbances, present in most patients from the initial stages of the disease, are also well recognized in PD [4-14]. While other cognitive domains may be impaired and eventually lead to dementia in PD [8,9,12], “frontal-type” executive deficits with impairment of attention and memory search strategies, slower visuomotor processing, reduced verbal fluency, impairment of organizational and constructional strategies on learning and copying tasks, and motor programming disturbances are characteristic and predominate over the course of the disease . Although other neurotransmitters may be deficient in advanced PD , “frontal-type” deficits can mainly be explained by the malfunctioning of the frontal-basal ganglia circuitry due to the progressive dopamine loss characteristic of PD [2,3,7,13,14]. In line with the facts that dopaminergic circuits are thought to regulate a diverse set of behaviors, including modulation of attention, cognition, mood, and reward, and that any of the dopaminergic drugs used to ameliorate the motor signs of PD act selectively on the motor circuits, it should be not surprising that dopamine replacement therapy (DRT) can be associated with a variety of striatal and extrastriatal effects exerting a significant influence on the mental status and behavior of PD patients. Nevertheless, the potential negative effects of DRT in patients' social interactions and quality of life were largely unfamiliar or simply neglected for several decades in everyday clinical practice.
|Title of host publication||Neuropsychiatric and Cognitive Changes in Parkinson's Disease and Related Movement Disorders: Diagnosis and Management|
|Number of pages||18|
|Publication status||Published - 1 Jan 2010|