Progressive Supranuclear Palsy and Diffusion Tensor Imaging

Clinical Features of Progressive Supranuclear Palsy Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterised by parkinsonism, supranuclear ophthalmoplegia, dysphagia and cognitive dysfunction. The National Institute of Neurological Disorders and Stroke (NINDS) PSP criteria are widely used for clinical diagnosis. However, the clinical phenotypes of pathologically confirmed PSP patients are heterogeneous. Recently, PSP has been clinically classified into two phenotypes: Richardson’s syndrome and PSP-parkinsonism. Those patients who have Richardson’s syndrome are neurologically characterised by the classic features, including the early onset of postural instability and falls, supranuclear vertical gaze palsy and cognitive dysfunction. PSP-parkinsonism is frequently misdiagnosed as Parkinson’s disease in its early clinical stage and is characterised by asymmetrical onset, tremor and moderate initial therapeutic response to levodopa. Differentiating between Richardson’s syndrome and Parkinson’s disease is not difficult, but differentiating between PSP-parkinsonism and Parkinson’s disease is occasionally challenging. Early differentiation of these diseases is necessary because the therapeutic strategy and outcome are substantially different (e.g. PSP patients have much worse prognosis).