Validation of the Utility of the Vietnamese Smell Identification Test in Vietnamese Patients With Parkinson's Disease

Rational Parkinson's disease is one of the most commonly neurodegenerative disorders neurological outbreaks with an incidence in Vietnam of 80-90/100,000 people. It comprises of motor and non-motor symptoms (NMS). Motor symptoms include tremor, bradykinesia, rigidity, gait difficulties, postural instability and falls. Non-motor symptoms are diverse including a wide range of symptoms involving almost systems of the body. A number of nonmotor symptoms may precede motor symptoms by several years, including olfactory dysfunction, constipation, REM sleep behavior disorder, and depression. Since1975, after Ansari and Johnson reported impaired olfactory function in Parkinson's patients, many studies have been conducted with the goal of demonstrating a diminished sense of smell in Parkinson's patients. Recent studies have noted that 70-90% of Parkinson's patients have hyposmia. Current evidence suggests that Parkinson's patients may experience disturbances in various aspects of olfactory function including odor detection, odor discrimination, and odor perception. However, some studies indicated that odor recognition function was more often affected than odor discrimination function. Nowadays, hyposmia is one of the supportive criteria in the diagnosis of Parkinson's disease based on the Parkinson's disease diagnostic criteria of the Movement Disorders Association. Besides, hyposmia when combined with other signs on DAT-Scan and on transcranial Doppler ultrasound help increase the accuracy in diagnosing Parkinson's disease.

There are many different tests available on the market to assess olfactory function for Parkinson's patients, of which the most commonly used tests are UPSIT (University of Pennsylvania Smell Identification Test), B-SIT (Brief Smell Identification test). Identification Test) and Sniffin's Sticks. UPSIT is an odor identification test, developed in 1984 with 40 different odorants. UPSIT has been shown to be highly reliable and valuable in the assessment of odor disorders 19. However, evaluating UPSIT took a long time, so a simpler version of UPSIT with 12 different flavors suitable for many cultures was created called B-SIT. These 12 scents were selected from surveys conducted in several countries in North America, South America, Europe and Asia. In Asia, surveys were conducted in Japan and China. Many studies have shown that B-SIT has good sensitivity and specificity in the diagnosis of Parkinson's disease. However, the popular assessment methods including UPSIT, B-SIT and Sniffin's Sticks were all developed in other parts of the world, so there are many odors in these tests that are not familiar to Vietnamese people. The 12-item Vietnamese smell identification test (VSIT) has been developed to evaluate olfactory function for the Vietnamese population. The VSIT demonstrated good validity and reliability. To date, there have been no studies evaluating the effectiveness of odor identification tests in diagnosing Parkinson's disease in Vietnam. Therefore, investigators conducted this study with the aim to assess the value of the VSIT in the diagnosis of Parkinson's disease, and compare it with the commonly used test in the world, B-SIT.

Primary research objective:

• To determine the sensitivity, specificity, positive predictive value, and negative predictive value of the VSIT in the diagnosis of Parkinson's disease?

Secondary research objective: