The therapeutic challenges in the older Parkinson's disease patient.

The information explosion in Parkinson's disease challenges the individual clinician to apply available knowledge to the management of individual patients. The application of current algorithms and guidelines is not straightforward in the older patient. Decision analysis reveals that clinical decisions may be simple, complex or chaotic. The more factors that have to be taken into account in making a decision, the more that decision moves from being evidence-based to intuitive. Decisions are made within conceptual frameworks. The dominant models in Parkinson's disease are biomedical or rehabilitation-based. Although the rehabilitation model lacks a sound evidence base, it is the principles of rehabilitation that dominate the management of the older patient. Analysis of the decisions made in a Parkinson's disease clinic demonstrates that the doctor's role is complex and many decisions taken are not evidence-based. Parkinson's disease is not a simple movement disorder but a neuro-psychiatric complex. The incurable nature and chronicity of the disease dictate the need for multidisciplinary working. Quality of life studies reveal wide variations in the expectations and needs of patients. Studies of the impact and costs of the disease put the cost of drugs into perspective. Studies in Parkinson's disease can involve very different populations. A cohort of elderly patients shows significant differences from the populations who are selected to participate in multi-centre trials. There is an increasing challenge for geriatricians to ensure that pragmatic trials are undertaken. Psychiatric problems - dementia, depression, and hallucinations - are common in the elderly and best management of these problems is unclear. Choices in drug regimes need to take into account the complex interactions between ageing, comorbility and Parkinson's disease.