[Psychiatric and cognitive complications arising from subthalamic stimulation in Parkinson's disease]

Subthalamic stimulation is a therapeutic option that can be used to treat advanced cases of Parkinson's disease. However, psychiatric or cognitive disorders have been reported in some patients treated using this technique. Age and a long disease history are two important risk factors for the appearance of these problems. The complications that have been reported include cases of depression, apathy, manias and psychosis. Surgery can also exacerbate the syndrome of addiction to levodopa that is sometimes observed. In contrast, sleep disorders usually improve with this technique. As far as the cognitive sphere is concerned, verbal fluency has been seen to deteriorate and the executive functions become impaired in patients over 69 years of age. These disorders are usually due to a number of different causes and have been attributed to the action of stimulating areas close to the subthalamic nucleus, to the presence of previously existing cognitive or psychiatric problems, to unrealistic expectations about this technique or to the individual's inability to adapt to the functional situation after surgery.

Although generally speaking these disorders are not usually serious, they must be borne in mind so that adequate treatment can be indicated.