[A case report of Parkinson's disease presenting with olfactory disturbance as a primary symptom in the early stage].

We report herein on a 71 year-old male who presented with olfactory disturbance at the early stage of Parkinson's disease (PD). Due to a persistent olfactory disturbance for 5 years, the patient visited our clinic and showed disorientation between the olfactory detection threshold and recognition in T&T olfactometry and scored 3 out of 12 points in OE. During the follow-up period, the typical symptoms of PD, including mask-like face and motor disturbance emerged, which led to the diagnosis of PD by the neurologist. Since it is generally accepted that olfactory disturbance precedes the appearance of motor disturbance in the early stage of PD, otolaryngologists should be aware of the necessity of olfactory tests for the patients with reported persistent olfactory disturbance, especially in elderly patients. In those cases where the patients present positive findings in olfactory tests without any particular cause, referral to neurologists is recommended.