Bilateral subthalamic nucleus stimulation in a parkinsonian patient with preoperative deficits in speech and cognition: Persistent improvement in mobility but increased dependency: A case study

We report a patient with advanced Parkinson's disease, including severe and frequent off periods with freezing of gait, moderate dysphonia, and some c ognitive impairment, who underwent bilateral subthalamic nucleus (STN) stim ulation. The patient was followed for 1 year after surgery, showing persist ent good mobility without off periods and without freezing, which reverted completely when stopping the stimulation, There was deterioration of cognit ion as well as increased aphonia and drooling, all of which remained when t he stimulation was turned off. The striking improvement in motor symptoms f ollowing STN stimulation was not paralleled by improvement in disability, p robably as a result of a cognitive decline, suggesting a diagnosis of Parki nson's disease with dementia. We conclude that chronic STN stimulation is e fficient in alleviating akinetic motor symptoms including gait freezing; th is surgery should be offered before patients start to exhibit speech or cog nitive disturbances.