The Sydney multicenter study of Parkinson's disease: the inevitability of dementia at 20 years.

After 20 years follow-up of newly diagnosed patients with Parkinson's disease (PD), 100 of 136 (74%) have died. The mortality rate fell in the first 3 years of treatment, then rose compared to the general population, the standardized mortality ratio from 15 to 20 years reaching 3.1. Drug induced dyskinesia and end of dose failure were experienced by most patients, but the main current problems relate to the non-levodopa responsive features of the disease. Dementia is present in 83% of 20-year survivors. Dementia correlates with increasing age and probably reflects an interplay of multiple pathologies. Seventeen people with dementia had postmortems. Eight had diffuse Lewy bodies as the only cause of dementia, while others had mixed neuropathology. Only one person lives independently and 48% are in nursing homes. Excessive daytime sleepiness is noted in 70%, falls have occurred in 87%, freezing in 81%, fractures in 35%, symptomatic postural hypotension in 48%, urinary incontinence in 71%, moderate dysarthria in 81%, choking in 48%, and hallucinations in 74%. The challenge is to understand the cellular mechanisms underlying the diverse features of advanced PD that go far beyond a lack of dopamine.

The progression of pathology in longitudinally followed patients with Parkinson's disease.

The present study describes the pathological progression of longitudinally followed cases with levodopa-responsive Parkinson's disease who came to autopsy during the Sydney Multicenter Study of Parkinson's disease. Standardised clinical and neuropathological assessments over five epochs of time verified three different clinicopathological groups. A group of younger onset patients with a typical long duration clinical course of Parkinson's disease. This group of cases had Lewy body distributions consistent with the Braak staging of disease. In this group, brainstem Lewy bodies dominate in those surviving to 5 years; by 13 years, 50% of cases have a limbic distribution of Lewy bodies; and by 18 years, all will have at least this pathological phenotype. Approximately 25% of cases had an early malignant, dementia-dominant syndrome and severe neocortical disease consistent with dementia with Lewy bodies. The last group had an older onset, shorter survival, and a more complex disease course with higher Lewy body loads and a higher proportion with additional neuropathologies. These cases with higher loads of Lewy bodies and shorter survivals suggest that widespread Lewy body pathology either occurs at the onset of clinical disease or rapidly infiltrates the brain. In these cases with shorter survivals, there was more plaque pathology, supporting a more aggressive and linked phenotype. Our data suggest that the selection of similar study cohorts by pathology alone would not be able to differentiate the three different phenotypes identified. The data are also not consistent with a unitary concept of the pathogenesis of Lewy body disease.

Anticipation of onset age in familial Parkinson's disease without SCA gene mutations.

Assessment of a series of 279 cases with Lewy body disease revealed 14 families having a family history consistent with autosomal dominant inheritance, eight of these with dominant Parkinsonism and six with dominant dementia. Analysis of the age at onset and genetic features in these families revealed significant anticipation only in a subset of parkinsonian families, with no pathological alleles for spinocerebellar ataxias or the common alpha-synuclein or LRRK2 point mutations.

Sydney Multicenter Study of Parkinson's disease: non-L-dopa-responsive problems dominate at 15 years.

One-third of the 149 people recruited 15 to 18 years ago in the Sydney Multicenter Study of Parkinson's disease have survived. The original study compared low-dose levodopa with low-dose bromocriptine. We now report the problems experienced by people who survive 15 years from diagnosis. The standardized mortality ratio is significantly elevated at 1.86 and is not significantly different between treatment arms. Falls occur in 81% of patients, and 23% sustained fractures. Cognitive decline is present in 84%, and 48% fulfill the criteria for dementia. Hallucinations and depression are experienced by 50%. Choking has occurred in 50%, symptomatic postural hypotension in 35%, and urinary incontinence in 41%. No patient is still employed, and 40% of patients live in aged care facilities. Although approximately 95% have experienced L-dopa-induced dyskinesia/dystonia and end of dose failure of medication, in the majority, these symptoms are not disabling. Dyskinesia and dystonia were delayed by early use of bromocriptine, but end-of-dose failure appeared at a similar time once L-dopa was added. The rate of disease progression is similar in both arms of the study. We conclude that the most disabling long-term problems of Parkinson's disease relate to the emergence of symptoms that are not improved by L-dopa. Neuroprotective interventions in Parkinson's disease should be judged by their ability to improve non-L-dopa-responsive aspects of the disease, rather than just by their capacity to delay the introduction of L-dopa or reduce its associated side effects.