A review of cognitive and other non-motor problems in Parkinson's disease

Until relatively recently, much of the research regarding Parkinson s disease had focused on the motor problems. However, over the last two decades, there has been an increasing focus on the non-motor symptoms that accompany this disorder. Problems such as anxiety and depression are often comorbid with Parkinson s disease. Difficulties with aspects of cognition are also frequently present and may include deficits in executive function, working memory, planning and visuospatial problems. There is an extensive body of research that has examined the range of cognitive problems that emerge early in the disease process and often progress to dementia. More recently, research in this area has focused on identifying a stage referred to as preclinical dementia or mild cognitive impairment. There are still a number of difficulties that prevent accurate classification of patients with Parkinson s disease who will experience cogntive problems. However, identifying a period of preclinical dementia offers an opportunity to intervene to stop or slow the progression to dementia for this group.