Parkinsonian syndromes are a group of movement disorders characterized by motor symptoms of tremor, rigidity, postural instability, and bradykinesia. Parkinson disease (PD) is the most common cause of Parkinsonism, with other common causes, including progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and vascular Parkinsonism, with a number of rarer conditions also within the differential. PD is a neurodegenerative disease and movement disorder characterized by progressive degeneration of the dopaminergic neurons in the substantia nigra/striatum. It is the most common Parkinsonism syndrome, with an annual incidence estimated at 10 to 18/100,000 in the total population and peak age of onset between 60 to 70 years [29]. PD, also known as idiopathic Parkinsonism, is a synucleinopathy with neuronal deposits of Lewy bodies (predominantly composed of alpha-synuclein and ubiquitin). Initially, Lewy body deposition is seen involving the medulla oblongata, pontine tegmentum, and olfactory system, with later involvement of the substantia nigra and other deep gray nuclei (corresponding to the onset of clinical symptoms), and finally with deposition of Lewy bodies in the cortex. The clinical presentation of PD is characterized by resting tremor, bradykinesia, and rigidity and is related to progressive degeneration of the dopaminergic neurons in the substantia nigra projecting to the striatum. The estimated interval between initial loss of dopaminergic neurons and the appearance of symptoms is approximately 5 years (after approximately 40% to 50% of the dopaminergic neurons in the substantia nigra have been lost) [29]. Other features include autonomic dysfunction, behavioral changes, and dementia.
Movement Disorders and Neurodegenerative Diseases. Parkinsonian syndromes are a group of movement disorders characterized by motor symptoms of tremor, rigidity, postural instability, and bradykinesia. Parkinson disease (PD) is the most common cause of Parkinsonism, with other common causes, including progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and vascular Parkinsonism, with a number of rarer conditions also within the differential. PD is a neurodegenerative disease and movement disorder characterized by progressive degeneration of the dopaminergic neurons in the substantia nigra/striatum. It is the most common Parkinsonism syndrome, with an annual incidence estimated at 10 to 18/100,000 in the total population and peak age of onset between 60 to 70 years [29]. PD, also known as idiopathic Parkinsonism, is a synucleinopathy with neuronal deposits of Lewy bodies (predominantly composed of alpha-synuclein and ubiquitin). Initially, Lewy body deposition is seen involving the medulla oblongata, pontine tegmentum, and olfactory system, with later involvement of the substantia nigra and other deep gray nuclei (corresponding to the onset of clinical symptoms), and finally with deposition of Lewy bodies in the cortex. The clinical presentation of PD is characterized by resting tremor, bradykinesia, and rigidity and is related to progressive degeneration of the dopaminergic neurons in the substantia nigra projecting to the striatum. The estimated interval between initial loss of dopaminergic neurons and the appearance of symptoms is approximately 5 years (after approximately 40% to 50% of the dopaminergic neurons in the substantia nigra have been lost) [29]. Other features include autonomic dysfunction, behavioral changes, and dementia.