Acknowledgement
We would like to acknowledge the use of information taken from the Parkinson’s Disease Society fact sheet Freezing in Parkinson’s in compiling this information.
Our thanks to Dr W Farid Abdo1for his help in reviewing this article.
Freezing is a temporary, involuntary inability to initiate or continue movement lasting just a few seconds or, on some occasions, several minutes. It happens suddenly, particularly when walking, as if the feet have become stuck to the ground and speech, writing or opening and closing the eyes can also be affected.
According to the Parkinson’s Disease Society UK almost a third of all people with Parkinson’s experience freezing.
Some people are more prone to freezing than others, but it tends to occur with increased frequency as Parkinson’s progresses. Although generally regarded as a late feature of the disease, some research has shown that freezing can occur during the early stages of Parkinson’s in those people who are not treated with levodopa.
It has also been suggested that freezing could be linked to taking levodopa for many years and that treatment with dopamine agonist may actually increase the frequency of freezing. Others believe that it is not dopamine, but other chemicals in the brain that cause freezing.
Whatever the cause, not everyone with Parkinson’s will experience freezing and it is impossible to accurately predict those who will. Freezing seems to be more prevalent in those whose initial symptoms included gait problems, and less prevalent in people who initially present with tremor.
The exact cause of freezing is unclear, but it is thought to occur when there is an interruption to a familiar or automatic sequence of movements. One theory is that freezing occurs when the brain fails to automatically adjust to a change in the length of a person’s stride. Some people with Parkinson’s find it difficult to judge spaces and they may struggle with narrow entrances or doorways, or stepping from a level to uneven ground, or moving from a plain to a patterned walking surface. But rather than the brain automatically adjusting the stride to cope with the situation, the person has to consciously think through the steps. It is this interruption of movement that is thought to trigger freezing. Similarly freezing may happen when making a turn, when reaching a target (e.g. a chair), or in crowded spaces as ‘auto-pilot’ is again disrupted and any movement must be consciously carried out. Stress, and performing a secondary task while walking also makes freezing more likely.
Unfortunately, freezing (and the likely preceding shuffling steps known as festination ) can upset balance, resulting in falls. This may discourage social activities and bring loss of confidence in carrying out daily tasks. It can lower morale and impact on quality of life, so it is important to explore ways of overcoming this problem and limiting its impact.
Freezing is also known as ‘motor block’.
The main type of drug prescribed to treat Parkinson's disease and has been in use since the late 1960s. The aim is to increase the levels of dopamine in the brain. Dopamine cannot be directly replaced because it cannot cross the blood-brain barrier that prevents potentially harmful substances in the blood from entering the brain. Levodopa is a chemical compound that can cross this barrier and is then converted into dopamine.
See also Types of medication available.
A class of drugs that work by stimulating the parts of the brain (know as dopamine receptors ) where dopamine works. Unlike levodopa, they don’t need to be converted by the brain cells first. They may be given as a first treatment to delay the need for levodopa or used in combination with levodopa to treat the side effects caused by long-term treatment.
See also Types of medication available.
A neurotransmitter produced in the substantia nigra, which forms part of the basal gangia in the brain. It sends messages from the brain to other parts of the body and has a major role in the control of movement. There is a shortage of dopamine in the brains of people with Parkinson's disease.
Rhythmic shaking of part of the body. It is one of the main symptoms of Parkinson's disease, although it is not experienced by everyone.
From the latin festino, meaning to hasten, festination is an involuntary shortening of stride and quickening of steps as if hurrying forward to keep balance. This appears as shuffling and hesitant steps when walking.
Having to do with the movement of a part of the body.
