Abstract
The medical treatment of Parkinson’s disease (PD) is often of limited effectiveness in patients with motor fluctuations, dyskinesias or severe tremor. Deep brain stimulation (DBS) can help some of these patients. DBS of the subthalamic nucleus (STN) has been the preferred surgical treatment over the last 10 years owing to improvement of a large range of symptoms. Several studies have shown improvement in quality of life (QoL) scales after STN-DBS, usually correlated with improvement in motor function. Other aspects – such as communication, cognition and social support – often do not improve. There has been some debate regarding the effect of STN-DBS in older groups of patients. Most surgical teams are very cautious about operating on patients over 70 years of age in the STN area; a study in 2000 by St-Cyr et al. had already pointed out a higher risk in decline in cognitive functions in an older group of patients. Two recent studies investigated outcome in older groups of patients. Ory-Magne et al. showed a negative correlation between age and improvement in three dimensions of the Parkinson’s Disease Questionnaire –39 items (PDQ 39) – mobility, activities of daily living and cognition – at 24-month follow-up. Apathy and depression were positively correlated with age, and the risk of bleeding was increased. Derost et al. have shown that despite an improvement in motor functions in both age groups, QoL improved only in the younger group. Several studies aiming to predict improvement after STN-DBS have found that relative youth is a positive factor. In conclusion, STN-DBS can improve some aspects of the QoL of younger patients with PD (those under 65/70 years of age). In older patients the risks are higher and there are fewer benefits; therefore, STN-DBS should be considered very cautiously.