A comparison of clinical and pathological features of young- and old-onset Parkinson's disease

Neuropathology in movement disorders

This review concentrates on the definition and classification of degenerative movement disorders in which Parkinsonian symptoms are often prominent. The pathological spectrum and clinical manifestations of Lewy body disease are described, and associations with Alzheimer's disease and motor neuron disease are explored. A classification of pallidonigral degenerations is based on clinical features, distribution of pathology, and morphological abnormalities; some of these patients have mild nigral degeneration and no Parkinsonian features. Many other juvenile and familial Parkinsonian cases are not included among the pallidonigral degenerations. Most of these latter syndromes have been organised into preliminary groups, in particular, autosomal dominant dystonia-Parkinson syndrome, juvenile Parkinsonian disorder and autosomal dominant Lewy body disease.

Dementia and Parkinson's disease

Recent research into the dementia of Parkinson's disease has exposed a complex area in which it has not always been possible to match clinical and pathological observations. Certain neuropsychological deficits result from a disruption of basal ganglia and frontal lobe interactions. These are unrelated to a global dementia, the prevalence of which exceeds twice that in the normal population. The associated pathological lesions comprise cortical pathology, either Alzheimer's disease or Lewy bodies, in combination with moderate degeneration of the subcortical, cholinergic, basal nucleus of Meynert.