Physicians look for a series of symptoms and conduct tests before making a Parkinson's diagnosis.
Since there is no standard clinical test for pinpointing the disease, doctors sometimes have a hard time making a Parkinson's diagnosis. They do, however, rely upon a variety of examinations and tests to determine whether a patient has Parkinson's disease (PD) and, if so, how far it has progressed.
The four primary physical symptoms of Parkinson's disease are tremors, slow movement (bradykinesia), postural instability and muscular rigidity. Tremors are the most common of these symptoms, occurring in 70 percent of patients during the early stages of the disease. Since other diseases produce tremors similar to those produced by PD, doctors usually look for an occurrence while the patient is still (hence their name, resting tremors).
The other three physical symptoms are detectable during a standard neurological examination. According to the Parkinson's Disease Foundation, patients with bradykinesia may take short shuffling steps when they walk and often have trouble starting, stopping or completing movements. Patients experiencing muscle rigidity often have decreased ranges of motion in their neck, shoulders and arms, which may cause cramps and pain. Doctors check patients for the final primary motor symptom, postural instability, with a simple test of reflexes and balance.
Generally, two of these four symptoms must be present in order for the examining physician to diagnose PD. Also, a doctor is more likely to make a diagnosis if the symptoms are only present on one side of the patient's body, as reported by the Mayo Clinic.
Patients with Parkinson's disease may also experience some secondary motor symptoms, including sexual dysfunction, drooling, problems swallowing, fatigue and speech problems. Patients don't always experience these symptoms, but when present they can help doctors make a diagnosis.
Many people with Parkinson's disease suffer from psychiatric disorders like anxiety disorders and depression. They are also much more likely to experience cognitive decline and dementia than other healthy adults. Each of these disorders have detailed criteria that must be met for someone to be officially diagnosed, but doctors can often spot their symptoms during basic examinations and treatment sessions for PD.
Certain complications of PD, like constipation, urinary incontinence, sleep disorders and compulsive behavior, also help doctors identify and diagnose the disease.
Unfortunately, many of the diagnostic tests doctors use to detect structural abnormalities in the brain cannot detect the microscopic, chemical changes that cause Parkinson's disease. According to the University of Maryland Medical Center, electroencephalograms (EEGs), MRIs and CAT scans, despite how accurately they depict the brain, are ineffective for a Parkinson's diagnosis.
There are also a handful of other diseases that can cause Parkinson's disease symptoms, such as essential tremor, progressive supranuclear palsy and multiple system atrophy. In order to rule out these and other possible causes of parkinsonism during the exam, doctors may test their patients' blood for hormonal imbalances and ask them to provide a detailed medical history.