Therapeutic Management of the Overlapping Syndromes of Atypical Parkinsonism.

Progressive supranuclear palsy, corticobasal degeneration and multiple system atrophy account for approximately 10% of neurodegenerative parkinsonism. Considerable clinical overlap exists between these disorders that extends to features considered characteristic of each disease. Clinical diagnostic criteria have attempted to increase the accuracy of clinical diagnosis as accurate diagnosis is necessary to inform prognosis and to facilitate the recognition of disease-modifying treatments. Currently no such treatment exists. Nevertheless, many clinical trials aiming to change the natural history of these diseases are ongoing. The spread and accumulation of abnormal proteins are among the pathophysiological mechanisms targeted. For the time being, however, only symptomatic treatment is available. Levodopa is used to treat parkinsonism, but patients usually show a poor or transient response. Amantadine is also used in practice for the same indication. Botulinum toxin can alleviate focal dystonic manifestations. Addressing non-motor manifestations is limited by the potential of available drugs to impact on other aspects of the disease. Most of the new symptomatic formulations under study are focused on orthostatic hypotension in multiple system atrophy. Exercise, occupational, physical, and speech therapy and psychotherapy should always accompany pharmacological approaches.