In Parkinson's disease, freezing (sometimes called motor block) is a sudden, brief inability to start movement or to continue rhythmic, repeated movements, such as finger-tapping, writing, or walking. Freezing most often affects walking, but it also can affect speech, writing, and the person's ability to open and close his or her eyes. It tends to develop later in the course of the disease.
Freezing can be very disabling when it affects the way a person walks, causing the person to stop as though his or her feet suddenly have become glued to the floor. It can result in falls that cause serious injury, such as hip fracture. Freezing may occur at an open doorway (most common), at a line on the floor, or in crowds. It may be more likely to occur if the person is anxious or under stress.
There are several tricks you can learn to help you become "unfrozen" when a freezing episode occurs.
- Step towards a specific target on the ground. Some people use handheld laser pointers to create a target.
- Place a cane or walking stick on the floor in front of you (or have someone else do it) and then step over it.
- Make your first step a precise, stiff-legged, marching-type step, with a long stride.
These or other techniques may help you overcome freezing and get moving again. Specially trained dogs and special devices are available that can help you if freezing is a severe or frequent problem.
Apomorphine (Apokyn) is a fast-acting dopamine agonist that seems to be helpful in treating freezing associated with Parkinson's disease. Apomorphine can be injected under the skin when muscles become "frozen." This medicine is best taken with an antinausea drug to prevent side effects of severe nausea and vomiting.
Changing a person's levodopa dosage may improve freezing. But this does not work in all cases.