This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Primary orthostatic tremor (POT) is a rare, progressive movement disorder that causes unsteadiness when standing still, due to a rapid tremor affecting the legs and trunk. The tremor is sometimes described as having “shaky legs,” and it improves or disappears when walking, sitting, or lying down. This may cause people with POT to attempt to sit again or walk immediately after standing, for fear of falling. People with POT may also experience tiredness, physical exhaustion, muscle stiffness or weakness, and/or pain. Symptoms tend to gradually worsen over time and may lead to the need for a mobility aid such as a cane, scooter, or wheelchair.
The diagnosis of POT relies on a clinical exam as well as a specialized test called a surface electromyogram (EMG), which measures electrical activity in the muscles. The cause of POT is not completely understood, but the disorder is thought to involve dysfunction of the brain’s ability to regulate nerve signals that control muscle activity. Some researchers believe that POT is a type of essential tremor.
Treatment usually involves medications used to control seizures (anticonvulsants) such as clonazepam or gabapentin. In some cases, treatment may include medications used for Parkinson’s disease (levodopa or pramipexole), and/or botulinum toxin (Botox) injections in the leg muscles. More than one therapy may be tried before finding one that helps. POT does not appear to alter life expectancy. However, quality of life for people with POT may be severely impaired due to physical symptoms, fear of falling, and uncertainty about the course of the disorder.
For more information, visit GARD.