Parkinson disease (PD) is a neurodegenerative disorder that is second only to Alzheimer disease in prevalence in the United States, with over 500,000 individuals currently diagnosed. Experts believe that the true incidence of the disorder could be closer to one million due to misdiagnosis or undiagnosed cases. PD is considered a disease of aging with the majority of individuals diagnosed after the age of 60 years, and only 5% to 10% prior to the age of 50 years. Like most chronic diseases, the cost of treating PD is high, with estimated costs exceeding $14 billion annually. Both the incidence and cost of the disease are expected to double by 2040 as the U.S. population ages (National Institutes of Health, 2019).

PD affects neurons in a specific section of the brain that produces dopamine. When dopamine is decreased, the ability to control movement is affected. The rate at which dopamine decreases varies by individual, with some living a long and relatively functional life and others progressing quickly. Like many neurological disorders, the cause of this neuron degeneration is not known. The greatest risk factors for PD are age, prolonged exposure to pesticides, and genetics-approximately, 10% to 15% of people with PD have a close relative who is also affected (American Geriatrics Society [AGS], 2017).

PD can present with both motor and nonmotor symptoms. Motor symptoms are the most common and can afflict one side of the body and then progress to the other side. Tremors at rest occur and often go away when the patient performs purposeful movements. Tremors can become worse with anxiety or stress. Slowed movements, also known as bradykinesia are a motor symptom. Bradykinesia can cause feelings of fatigue and weakness, and contributes to the characteristic short shuffling gait and falls due to the inability to adjust one's footing quickly. Patients with bradykinesia have difficulty starting sentences and getting words out when they speak; they also have difficulty with skills like typing, buttoning, and brushing their teeth. Rigidity or muscle stiffness causes the limbs and torso to stiffen, resulting in discomfort and increased difficulty with movement and range of motion. Postural instability or lack of balance causes the patient to sway back and forth or remain in a sitting position for very long. Postural instability usually occurs later in the disease and often results in the individual becoming wheelchair-bound or requiring assistance to move. Other common motor symptoms include: freezing or sudden stopping, slurred or flat sounding speech, and stammering. Swallowing problems with excessive saliva and drooling, micrographia (gradual shrinking of handwriting), visual changes, and hypomimia, or the loss of facial expression often referred to as masking, are also common (AGS, 2017).

Nonmotor symptoms of PD consist of: changes in memory and thinking-40% of individuals with PD develop short-term memory problems or dementia. Some individuals will develop hallucinations or delusions and become paranoid. Individuals with PD can become depressed, develop apathy, anxiety, and irritability. Sleep disorders with fatigue during the day exacerbate all symptoms and make day-to-day functioning very difficult. Autonomic dysfunction can cause a drop in blood pressure, constipation, urinary incontinence and retention, and sexual dysfunction. Loss of smell (anosmia) usually occurs early in the illness. Pain that can be sharp, stabbing, burning, or tingling can occur in parts of the body affected by motor symptoms (AGS, 2017).

There is no cure for PD, but there are medications and treatments that can improve quality of life and lessen symptoms. Medications are often introduced when symptoms interfere with an individual's daily function. The most effective medication for PD is levodopa-carbidopa, due to its ability to replace the dopamine. Symptoms of bradykinesia, tremors, and rigidity can be improved with the use of levodopa-carbidopa. Other medications used to treat motor symptoms include: monoamine oxidase inhibitors, dopamine agonists, catechol-O-methyl transferase inhibitors, anticholinergics, and amantadine. Deep brain stimulation is a procedure where wires are placed in the motor areas of the brain and connected to an internally placed device that sends electrical impulses to the brain to reduce abnormal movements. Treatment for nonmotor symptoms can include medications for depression and sleep disturbance, memory agents to treat dementia, and antipsychotics to manage hallucinations and delusions. Levodopa-carbidopa should be monitored closely as it often contributes to increased hallucinations, delusions, and confusion in older individuals (AGS, 2017).

Individuals with PD can benefit from a multidisciplinary approach. Interventions target quality of life with symptom reduction while maximizing function and independence. Every member of the healthcare team can support the patient and family by encouraging support groups and resources that provide education and an opportunity to interact with other people and families on the shared experience of PD. Both the American Parkinson's Disease Association at http://www.apdaparkinson.org and the Parkinson's Foundation at http://www.parkinson.org provide education, updates on treatment and research as well as lists of local support groups and organizations.

The PD patient will require the services of the home healthcare team-nurses, social work, physical therapist, occupation therapy, speech and language therapist, and dietitians. Physical therapists work with the patient on balance and strength, the management of freezing, and rigidity by improving range of motion and muscle strength. In addition, they can educate patients on the use of assistive devices and safe ambulation to decrease fall risk and prevent injury. Physical therapists can develop a plan of daily exercise that will improve mood and help the patient feel more confident and in control of PD.

Occupational therapists (OT) work with the patient to maintain optimal and safe function in daily activities. This is not limited to, but will include, an evaluation of the home for safety and recommendations for assistive devices for feeding, dressing, and toileting. The OT may also assess driving skill to determine if the patient is safe behind the wheel.

Speech therapists and registered dietitians will work with PD patients to treat speech and swallowing problems to improve eating and communication. The dietitian can recommend a diet to enhance and optimize nutritional intake. Often PD patients struggle to maintain weight; the dietitian can reinforce adequate hydration and help patients schedule meals around medications to avoid the impact of protein in reducing the effectiveness of levodopa-carbidopa in some patients.

Individuals diagnosed with PD often manifest the symptoms of the disease for many decades and can benefit immensely from interventions by the home healthcare team. It is important for clinicians to thoroughly assess the needs of these patients and provided timely interventions to promote independence and quality of life.

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