The goal of this observational study is to assess the value of the Vietnamese smell identification test (VSIT) in the diagnosis of Parkinson's disease, and compare it with the commonly used test in the world, Brisk smell identification test (BSIT)

The main questions it aims to answer are:

• The sensitivity, specificity, positive predictive value, and negative predictive value of the VSIT in the diagnosis of Parkinson's disease?
• The sensitivity, specificity, positive predictive value, and negative predictive value of the BSIT in the diagnosis of Parkinson's disease?
• Factors that associated with olfactory identification ability in PD patients?

Process:

• Participants will be assessed cognitive station using MMSE
• Information on socio-demographic including age, gender, education, occupation, place of residence of both groups, and disease-related characteristics will be collected.
• Participants with Parkinson disease will be then assessed with the following instruments: Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Hoehn & Yarh scale, and Beck Depression Inventory
• The case and control groups will be assessed by the Vietnamese Smell Identification Test and Brisk Smell Identification Test

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:

• To determine the sensitivity, specificity, positive predictive value, and negative predictive value of the BSIT in the diagnosis of Parkinson's disease?
• To find factors that associated with olfactory identification ability in PD patients?

Approach to participants:

• Patients and controls attending the Parkinson and Movement disorder clinic at UMC will be approached by one of the researchers about the study when the patients come for their regular visit

Research Process:

• Participants will be assessed cognitive station using MMSE
• Information on socio-demographic including age, sex, education, occupation, place of residence of both groups, and disease-related characteristics will be collected.
• Participants with PD will be then assessed with the following instruments: Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Hoehn & Yarh scale, and Beck Depression Inventory
• The case and control groups will be assessed by the Vietnamese Smell Identification Test and Brisk Smell Identification Test

Inclusion Criteria:

• Aged 18 years and older
• MMSE score > 24
• Clinical diagnosis of Parkinson's disease (for patient group)

Exclusion Criteria:

• History of trauma to the head, history of nasal bone fracture, and history of nasal cosmetic surgery
• Brain neoplasms
• History of stroke, epilepsy
• Secondary Parkinson's and Parkinson's Plus
• Other neurodegenerative diseases, such as Alzheimer's
• Mental disorders, such as schizophrenia, depression
• Upper respiratory tract infections in the 2 weeks
• Pregnancy
• Exposure to medications relating to olfactory reduction, for instance, some particular antibiotics, antiepileptics, antithyroid or benzodiazepines
• Having reported COVID-19 compatible smell symptomatology

Population: Parkinson's disease patients and healthy control

Target Population:

1. Parkinson's disease patients attend the Parkinson and Movement disorder clinic at Ho Chi Minh University Medical Center

Control Population:

1. The participants included hospital staffs and relatives of patients that matched age and sex

We will share study protocol, SAP, ICF, CSR