Analysis of freezing gait

  What is the experience of “freezing gait”? A better description of freezing gait is like this: the feet suddenly appear as if they are attracted by a huge invisible magnet, so they seem to be stuck or nailed to the floor, unable to move. As the torso is leaning forward, the feet “freeze” and it is very easy to fall. Described in academic terms, it is: the onset of effective forward stride can not be seen in the gait start and turn.  Freezing gait is something most of us have never felt before, but it is a common clinical symptom in Parkinson’s patients and is an important cause of falls and disability, so timely detection and treatment is important. Freezing gait is rarely seen in the early stages of Parkinson’s disease, so if a patient has a freezing gait as the first symptom, the first thing to consider is the possibility of atypical Parkinson’s. In addition, “freezing” is not limited to gait, but can also occur with alternating repetitive movements of the fingers and speech during presentations.  There are no guidelines for the treatment of frozen gait, but they are summarized below based on expert consensus. The first step in the treatment of frozen gait is to determine whether it is having a serious impact on the patient’s life. A severe impact is usually defined as a serious disruption of the patient’s mobility and quality of life, such as frequent episodes of falling. In mild cases of frozen gait, daily living and walking functions can be compensated for. Given the paroxysmal nature of freezing gait, both mild and severe patients need to be aware of the risk of falls, the multiple precipitating factors, and possible preventive measures. The main preventive measures include shifting the weight to the opposite leg before stepping, increasing the turning radius when turning, working and living in a spacious environment, maintaining emotional stability, and focusing on gait while walking.  Physiotherapy is preferred for mild cases, such as consciously increasing stride length and maintaining a regular walking rhythm to reduce the onset of “freezing”. Patients should be encouraged to exercise moderately, especially cycling is recommended, as cycling is rarely associated with “freezing” episodes. Pharmacological treatment with monoamine oxidase B inhibitors (e.g., resagiline, selagiline) is recommended and has been shown in several clinical studies to reduce the incidence of freezing gait.  Treatment options for severe patients are more complex and require a detailed evaluation by a movement disorder specialist (or sometimes a rehabilitation therapist). Treatment is generally threefold: pharmacologic and surgical, non-pharmacologic, and comorbid treatment. Freezing gait can be classified into three categories based on different responses to dopamine: dopamine-responsive (due to lack of dopamine in the central nervous system), dopamine-induced (due to ingested dopaminergic drugs) and dopamine-resistant (due to non-dopaminergic brain tissue damage). The dopamine-responsive type is the most common type and is treated by increasing the dosage of levodopa, shortening the interval between dopaminergic drug administrations, decreasing the dosage of dopamine agonists (which increase episodes of freezing gait), adding amantadine, and surgery when appropriate, but the choice and use of each treatment modality has strict indications and requires specialist evaluation. Both dopamine-induced and resistant forms are rare. The principle of treatment for the inducible form is to reduce the use of dopaminergic drugs, while the treatment for the resistant form is not yet definitive, with some reports suggesting that the combination of droxidopa and entacapone is effective. The non-pharmacological treatment is mainly physical therapy, similar to that for milder patients, but more specialized occupational therapists are recommended to guide and plan the details of all life activities of the patient. The treatment of comorbidities includes various aspects, such as cognition, anxiety, depression and postural hypotension, and timely management of anxiety and depression is thought to be effective in reducing episodes of freezing gait.  The purpose of this article is to give the reader a preliminary understanding of “freezing gait”, as the saying goes, “if you know your enemy, you will never lose a battle.