Olfactory dysfunction in Parkinson' disease diagnosis

Abstract

Parkinson's disease is a common neurodegenerative disorder of unknown cause and with inevitably progressive character. The disease has a long preclinical period-premotor phase when the nonmotor symptoms are in the first plan and when is the time which neuroprotective therapy should start. One important biomarker for the premotor phase of idiopathic Parkinson's disease is olfactory dysfunction. This deficit is frequent, significant, small-changes once motor features are evident and it is independent of motor and cognitive status and medication use. Smell loss affects all areas of olfaction and is easily measured by standard quantitative tools. The objective of this study is to evaluate the frequency and character of olfactory dysfunction among 40 patients, recently diagnosed with Parkinson's disease, as well as to assess correlations between olfactory function and the stage, duration or type of Parkinson's disease. Olfactory function was assessed using a 12-marker Smell Test: Sniffin' Sticks-Screening 12. This is a validated method of identification of sense of smell that can be used easily and quickly. The percentage summed of patients with hypoosmia and anosmia at this testing was important and the study finds no correlation between olfactory function and duration or stage of Parkinson disease. Hyposmia is one of the cardinal early symptoms of Parkinson's disease and can be evaluated as marker of the premotor state.