Diagnosis - Medical History & Physical Exam
The process of getting a diagnosis of Parkinson’s disease (PD) usually begins with a medical history and physical exam. A medical history generally consists of written and verbal questions to understand the symptoms the patient is experiencing and how long symptoms have been present, as well as understanding the health history of close relatives. The medical history also records any medications the person is taking, which may be causing some of the symptoms as a side effect of the treatment.
During a physical exam, the doctor examines the patient’s body for signs of disease. The doctor will include a visual inspection (looking), palpation (feeling), ascultation (listening, often with a stethoscope), and percussion (producing sounds through tapping). The physical exam for PD is generally conducted by a neurologist and may also be called a neurological exam. It is recommended that a patient see a neurologist with special training in movement disorders as these specialists have the most knowledge about the symptoms and medications. During a neurological exam, the patient may be asked to sit, stand, walk, and extend their arms as the doctor evaluates balance and coordination. Most neurologists recommend a spouse or caregiver attend the exam with the patient to help with answering important questions.1,2
Symptom history of Parkinson’s disease
Diagnosis of PD is most often made when a doctor identifies the primary motor symptoms in a patient. Diagnostic criteria for PD called the Unified Parkinson’s Disease Rating Scale (UPDRS) recommend that the physician assess for symptoms such as tremor, rigidity, balance impairments, freezing episodes (sudden, temporary inability to move), posture, changes in handwriting, difficulty swallowing, and reduced facial expression.3,4
In addition to these primary motor symptoms, the symptom history for diagnosing PD should include investigating the presence of non-motor symptoms of PD, such as constipation, a frequent and urgent need to urinate, sleep disturbances, pain, orthostatic hypotension (a drop in blood pressure that occurs upon standing), reduced sense of smell (hyposmia), sexual dysfunction, and fatigue. In addition, many people with PD experience mood disorders like depression or anxiety and cognitive changes, such as memory difficulties, slowed thinking, or confusion.4,5
Pattern of symptoms in Parkinson’s disease
While the motor symptoms are the current standard for diagnosing PD, research has shown that PD non-motor symptoms, particularly gastrointestinal symptoms and the reduced sense of smell, may begin years before the motor symptoms appear. When the motor symptoms show up in the body, they generally begin on one side of the body. This is called unilateral presentation. As the disease progresses, the symptoms may spread to the other side of the body as well.3,6
PD is a progressive disease, and the symptoms worsen over time. This progression of symptoms is also noteworthy when considering a diagnosis of PD.3
Ruling out other conditions
The symptoms of PD are similar to symptoms caused by other conditions, and an important part of the diagnosis process is excluding other diseases that may be the source of the patient’s symptoms. Other diseases that could cause similar symptoms include stroke, hydrocephalus, or other neurodegenerative disorders. Some medications can also cause Parkinson’s like symptoms, and the doctor will assess these. Good responsiveness to levodopa for the motor symptoms is indicative of PD. However, many clinical trials need patients newly diagnosed with PD that have never taken levodopa. So, it may be worthwhile discussing participation in clinical trials with the doctor first.1
Other tests used to diagnose Parkinson’s disease
Diagnosis of PD is generally made using a medical history and a physical/neurological exam. Imaging tests, such as MRI (magnetic resonance imaging), PET (positron emission tomography) scans, or DaTscans are expensive and are not routinely used.1,7
An active area of research is the development of “biomarkers” which are molecules in the blood, urine, or cerebrospinal fluid that can reliably indicate PD. Imaging tests that can detect aggregates of a molecule called synuclein, which is linked to PD, are also being actively researched.