Motor Symptoms of Parkinson's Disease

Parkinson’s disease (PD) is a slowly progressing neurodegenerative disorder that mainly affects the motor system. It can cause tremors in many people but not in all cases. Slowing of movement and muscle stiffness are also common. About 60,000 people in the U.S. are diagnosed with PD each year with the prevalence being 1.5 greater in men than it is in women.

PD tends to occur with advanced age (60 and over) with only 4% of people diagnosed before 50 years of age. According to the Parkinson’s Foundation, the economic burden of PD totals nearly $52 billion yearly. PD medications alone can cost up to $2,500 each year and surgery costs an estimated $100 billion annually.

Signs and symptoms

Resting tremors are those that occur when a person is not moving. They may start in the hands and fingers before developing into a “pill-rolling” tremor, which causes someone to rub their thumb and finger back and forth repetitively.

Bradykinesia or slowed movement is common with PD. This may be accompanied by shorter steps and dragging feet.

Muscle stiffness can make movements painful and reduce the range of motion.

Stooped posture, which affects balance.

Decrease in automatic movements, such as blinking and smiling.

Facial stiffness or Mask face, which stems from reduced facial expressions and decreased eye movement.

Changes in speech: monotone, soft, fast speech, or slurring.

Problems with fine motor tasks and writing (micrographic or small writing).

Slow, shuffling, and hesitant gait.

Freezing episodes that cause someone to stop in the middle of a movement.

Causes

The symptoms of PD are caused by neurodegeneration in the substantia nigra area of the brain, which results in a breakdown of nerve cells producing dopamine. The cause of this cell death is poorly understood but involves the build-up of misfolded Alpha-synuclein proteins that cells cannot break down and eliminate, so they lump together forming Lewy bodies. When dopamine levels decrease, abnormal brain activity occurs leading to the development of movement problems and other PD symptoms.

People who have family members with PD can be slightly more prone to developing this disease as studies indicate that ~5-15% of cases can be attributable to genetic factors. Other causes can be related to a person’s medical history, such as previous head trauma, or environmental factors (pesticides, herbicides, or polychlorinated biphenyls (PCBS) that were used in industrial processes).

Hoehn-Yahr five stages

In 1967 Margaret Hoehn and Melvin Yahr published a five-stage system for diagnosing and staging Parkinson’s disease. This rating scale is used to evaluate a person’s movement symptoms, self-care abilities, and level of independence. Since then, various scale modifications had been proposed, including adding stages 1.5 and 2.5 to help describe the intermediate course of the disease.

Stage 1

This is the earliest stage of PD that involves mild symptoms without an impact on self-care. Tremors and symptoms influencing movement on one side of the body may be present along with some mild changes in facial expression, posture, and walking.

Stage 2

Symptoms worsen during this stage. This includes rigidity on both sides of the body and more obvious changes in walking and posture. Speech abnormalities may also be present. The patient is still able to live alone, but daily self-care tasks will take more time and effort.

Stage 3

Symptoms such as loss of balance and coordination may result in falls. Movement is very slow. The patient can still be independent but may need help with basic self-care activities like eating, grooming, dressing, and bathing.

Stage 4

Tasks become very challenging due to severe symptoms. The patient may be able to stand without help but needs a walker to get around. They will need assistance with all self-care tasks and household management. As a result, someone in this stage may no longer be able to live alone.

Stage 5

The most debilitating and advanced phase of PD. The patient may no longer be able to stand or walk due to significant muscle stiffness. They will either be bedridden or rely on a wheelchair to get around. This stage warrants round-the-clock care. New symptoms may develop such as delusions, hallucinations, mood disorders, and other non-motor symptoms such as impaired cognition, sleep disorders, changes in taste and smell, reading difficulty, quick fullness when eating, urinary urgency, and incontinence.

Diagnosis

You may first be diagnosed with PD by your physician who may refer you to a neurologist (a physician who diagnoses, treats, and manages conditions that affect the brain and nervous system, including PD, Alzheimer’s Disease, Multiple Sclerosis, Brain Tumors, and Stroke). There is no other way to diagnose PD except through observations and questions. Observations may include noting symptoms such as tremors, muscle stiffness, lack of facial expression, ability to stand up from a chair, and walking difficulties. Doctors may test your balance to see how quickly you can regain it if your equilibrium is disturbed.

Since there is no standard test for PD, this condition is diagnosed based on the results of a neurological examination and information reported by patients and caregivers. The diagnosis of Parkinson’s Disease is made by excluding the possibility of other medical conditions and events, such as a stroke. Symptom progression and frequency vary from person to person.

Medical treatments

Patients may receive medications after an individualized assessment of the risks and benefits of their use and the age of the client upon diagnosis. In general, the goals of treatment for patients under 60 include controlling the progression of PD symptoms while protecting existing neurons. The primary medication choices for patients under the age of 50 include Eldepryl, Gocovri, and anticholinergic agents such as Artane and Cogentin. Patients in their 50s may require a dopamine agonist such as Mirapex in addition to or instead of Eldepryl to keep symptoms in check. If the desired response is still not achieved, a drug such as Sinemet should be added, followed by adjunctive Gocovri or anticholinergic therapy.

For patients who are 60 years and older, the primary goal is to improve existing functional impairments. For these patients, care is taken to avoid causing or worsening cognitive impairments. Sinemet CR is considered a first-line treatment for these patients. If this garners an inadequate response, providers can recommend a trial of immediate-release Sinemet and the addition of a dopamine agonist such as Mirapex once the maximum Sinemet doses are reached. Eldepryl, Cocovri, and anticholinergic agents such as Artane and Cogentin should be avoided because of their central nervous system side effects, such as insomnia, nervousness, lightheadedness, and seizures.

There are several surgical procedures used to treat Parkinson’s Disease. Stimulation and deep brain stimulation (DBS) involve implanting electrodes in the brain that can modify or block PD symptoms. Transplantation or restorative surgery consists of transplanting dopamine-producing cells from pigs or human embryos into certain areas of the brain.