Parkinson's Disease

What is Parkinson’s Disease?

Parkinson’s Disease (PD) is a degenerative movement disorder that results from the loss dopamine-producing cells in the brain. Parkinson’s disease motor features are characterized by tremor, slowed movements (bradykinesia), muscle rigidity, and postural instability. As the disease progresses, the motor symptoms may interfere with activities of daily living. PD typically affects people over the age of 65; however, 15% of those with PD are under the age of 50. There are approximately 1.5 million Americans who currently have PD with 60,000 new cases each year.

Signs and Symptoms of Parkinson’s Disease

There are several Parkinson’s disease motor symptoms including:

Tremor

Tremor (shaking) associated with PD typically occurs at 4-6 Hz when the arm is at rest and decreases in amplitude during voluntary movement. Tremor is characterized by amplitude and frequency, which can be measured using accelerometers or gyroscopes.

Bradykinesia/Akinesia

While tremor is the most well known symptom of PD, bradykinesia/akinesia can be the most debilitating. Bradykinesia and akinesia refer to the slowness or absence of movement, respectively. Clinicians examine speed, amplitude, hesitations, fatiguing, and arrests in movement when evaluating bradykinesia. Motion analysis systems can be used to objectively evaluate the kinematics of bradykinesia.

Rigidity

Rigidity, or muscle stiffness, increases resistance to passive movement. When combined with tremor, rigidity produces a ratchet-like movement known as cogwheeling.

Postural Instability

Postural instability can lead to impaired balance and coordination, which can lead to falls.

Other Parkinson's Disease Motor Symptoms

Other motor aspects of PD include disturbances in gait, swallowing, speech, fatigue, handwriting, infrequent blinking, and difficulty standing.

Non-motor signs of Parkinson’s Disease

In addition to motor symptoms, patients with PD can experience mood disturbances, dementia, short term memory loss, excessive daytime sleepiness, REM sleep behavior disorder, as well as various perception and autonomic disorders.

What Causes Parkinson’s Disease?

Parkinson’s disease results from the loss of dopamine producing cells in a part of the brain called the substantia nigra. Dopamine is a neurotransmitter that facilitates smooth, coordinated movements. Most cases of PD have no specific cause; however, current research suggests that PD may result from environmental toxins, head trauma, and possibly genetics.

Treatment

There is no cure for PD, but many medications can offer relief from the symptoms. Most medications, such as Levodopa, attempt to replace the lost dopamine in the brain. However, overmedication can result in wild, uncontrolled movements known as dyskinesias. When the disease does not respond adequately to medication, a therapy known as deep brain stimulation (DBS) can be utilized. In DBS, an electrode is implanted in the brain to send electrical impulses that can alleviate many of the motor symptoms.

Diagnosing Parkinson’s Disease

Parkinson’s disease can be difficult to diagnose. There is no x-ray, blood, or laboratory test that can diagnose PD. Typically, the diagnosis is based on medical history and a neurological exam using the Unified Parkinson’s Disease Rating Scale (UPDRS), a subjective rating scale that includes sections for evaluating mental function, activities of daily living, motor function, and complications of therapy.

CleveMed’s Division of Movement Disorders offers Kinesia™, a wireless movement disorder monitor containing accelerometers and gyroscopes for measuring hand and finger movements in three-dimensions. The Kinesia system objectively measures the kinematics of tremor, bradykinesia and dyskinesias, which can aid clinicians in properly adjusting medication or DBS therapy. The system can be used for Parkinson’s disease monitoring and to quantify Parkinson’s disease motor symptoms such as tremor frequency and tremor amplitude.