Currently, the diagnosis of Parkinson’s disease primarily relies on taking a thorough medical history and conducting a physical examination. The diagnosis is based on the presence of characteristic motor symptoms, including:

• Tremor
• Rigidity
• Bradykinesia or Hypokinesia 
• Postural instability
• Freezing of gait

      These are often accompanied by non-motor symptoms, such as constipation, sleep disturbances, and psychiatric or cognitive issues. The diagnostic accuracy by neurologists is approximately 80%, particularly after observing the patient over multiple visits. However, in early-stage Parkinson’s disease, when symptoms are still subtle or incomplete, the accuracy may drop to around 40–50%. This makes early diagnosis challenging, and many cases remain underdiagnosed. 

       In Thailand, the situation is further complicated by a limited number of neurologists, and in some regions, there is a shortage of specialists altogether. As a result, patients in certain areas have limited access to diagnosis and treatment services. Consequently, by the time patients are formally diagnosed, they are often already in the mid-stage of the disease, exhibiting more pronounced symptoms. This leads to higher treatment costs, increased disability, and significant impacts on quality of life.