Symptoms - Postural Instability and Balancing Issues

A balancing issue, or postural instability, is one of the primary motor symptoms of Parkinson’s disease (PD) that usually emerges in the late stages of the disease. Postural instability appears as a tendency to be unstable when standing, as PD affects the reflexes that are necessary for maintaining an upright position. A person who is experiencing postural instability may easily fall backward if slightly jostled. This is one of the most disabling symptoms because of the increased chance of falls. Postural instability is one of the four primary motor symptoms of PD, although not all patients with PD experience issues with balance. The other primary motor symptoms are tremor (particularly a tremor when the limb is at rest), rigidity (an abnormal stiffness in a limb or part of the body), and bradykinesia (gradual loss and slowing down of spontaneous movement).1

How postural instability may appear

Patients with PD experience symptoms in varying severities, and with the progression of the disease, the severity of the symptoms changes over time. Postural instability may show up during a variety of activities, including:

  • When rising from a chair
  • When rising from bed
  • While turning or pivoting, especially quick movements
  • While standing upright1

Postural instability may be apparent at diagnosis, but it is more commonly seen and worsens as PD progresses. The inability to balance and recover from variations in movement often causes falls, which can lead to hospitalization or death in people with PD. Because of this, postural instability is one of the most distressing symptoms of PD and greatly diminishes the individual’s level of mobility.2,3

Why does Parkinson’s disease cause postural instability?

Many of the motor symptoms of PD are caused by damage to the brain’s neurons (nerve cells) that produce dopamine, the neurotransmitter (chemical messenger) that relays the message in the brain to produce smooth, purposeful movement. However, postural instability is not linked to reductions in dopamine and is believed to be the result of damage to other parts of the brain. While the exact disease process that causes postural instability is not precisely understood, one theory is that it may be due to damage of noradrenergic neurons, which are the nerve cells that produce the neurotransmitter norepinephrine.4

Assessing balance issues

One of the tests that may be performed to assess a patient’s balance is called the “pull test.” While the patient is standing, a trained movement disorder specialist gives a moderately forceful backward tug on the patient and monitors how the patient recovers. Normally, an individual would take a quick step backward to keep from falling; however, many people with PD cannot recover from a tug like this and would fall backward if the doctor wasn’t there to catch him or her.1

Treating balance issues

There is no known cure for PD at this time, and there are not currently any treatments to slow or stop the natural progression of the disease. Most patients with PD are started on medication to help manage their symptoms. Medications that affect dopamine, including levodopa (administered with carbidopa) and dopamine agonists, can help improve postural instability in the early to mid-stages of PD, but their effectiveness decreases as the disease progresses.2

For some people with PD whose symptoms are not adequately controlled with medication, surgery to perform deep brain stimulation may be an option. As with medication, surgery does not cure or change the course of the disease progression, but it may help with the symptoms of PD. However, deep brain stimulation provides only modest benefit for postural instability.2,5

Physical therapy, particularly balance exercises, can also help improve postural instability.2

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Written by: Emily Downward | Last reviewed: March 2017