What is Holmes Tremor?
In 1904, a man named Gordon Holmes noticed that some people with specific brain injuries had shaking symptoms, which is now known as Holmes tremor. This type of tremor can occur either when a person is at rest or when they are moving. It is often linked to maintaining a continuous position and is usually slow (less than 4.5 Hz) but strong in intensity.
This shaking is also known by other names like rubral tremor, midbrain tremor, thalamic tremor, post-traumatic tremor, or complex tremor, which represent the different areas of the brain that it can affect. Initially, it was thought that the tremor was mostly connected with injuries in the midbrain. However, it’s now understood that it can be linked to damage in many other areas of the brain as well.
What Causes Holmes Tremor?
Holmes tremors, a type of shaking in the body, can be triggered by several different conditions. These include:
– Stroke: This happens when the blood supply to a part of your brain gets cut off. It can be of two types – ischemic, which happens when there’s a blockage, and hemorrhagic, which happens when there is bleeding in the brain.
– Trauma: Any injury to the body, such as a sudden blow or jolt, can cause these tremors.
– Neurodegenerative conditions: This refers to conditions that cause your neurons (nerve cells) to break down and die. One example of such a condition is multiple sclerosis, a disease in which your immune system mistakenly attacks your own body.
– Tumors: Growths or lumps, whether harmless or not, can also lead to Holmes tremors.
– Infectious: An invasion of the body by disease-causing agents can sometimes trigger these tremors.
– Progressive multifocal leukoencephalopathy: This is a rare and usually deadly viral disease that gradually destroys the white matter (‘leuko’) in the brain. ‘Encephalopathy’ refers to any kind of brain disease.
– Vascular lesions: This is a general term for a damaged or diseased blood vessel. It covers things like cavernoma, which is a cluster of abnormal blood vessels, and arteriovenous malformations, which are tangles of abnormal blood vessels. These can also cause Holmes tremors.
Risk Factors and Frequency for Holmes Tremor
Holmes tremor is a rare condition, with only a small number of cases reported in medical literature. This might be because some cases are incorrectly diagnosed as a different type of tremor, or because individual case reports aren’t always published. For example, a 2016 study found only 155 reported cases of Holmes tremor since the condition was first described in 1904.
- The average age at diagnosis is roughly 30.6 years, with patients’ ages ranging from 8 to 64 years old.
- Interestingly, it seems that women are twice as likely as men to be diagnosed with this condition.
- The time between when a patient first experiences an injury or ‘lesion’ and when the tremor begins varies greatly—it can be as short as one month or up to two years.
- Another study found that, typically, the tremor starts about 29 days after the initial lesion. Though in some cases, this can range from just 2 days to as long as 20 months.
Signs and Symptoms of Holmes Tremor
Diagnosing a tremor mostly involves a thorough clinical checkup, specialized nerve tests, and imaging assessments like X-rays or scans.
A neurological exam can reveal shaking that’s usually stronger on one side and more in the inner parts of the limb than the farther ends. This shaking is often more noticeable when at rest, but could get worse when trying to do something. It typically occurs below 4.5 times per second. If you hold a pose for a long time, the tremor might get more pronounced.
Doctors often use a tool called the Fahn-Tolosa-Marin tremor rating scale to determine how severe the tremor is. This measurement can help to see whether a certain treatment is working, by comparing the severity before and after treatment.
Testing for Holmes Tremor
Usually, lab tests don’t provide specific diagnosis for tremors. There’s a special test called an electromyogram, which is used to measure how often the tremors are happening.
If you have sudden or severe symptoms, the doctor might recommend a head CT scan. This can tell if there’s any bleeding in the brain. However, the most comprehensive test is a brain MRI, which can be done with or without contrast. The contrast is a type of dye that can make certain parts of the brain show up clearer in the pictures. Brain MRI is a very detailed scan that can show areas of the brain that might have been damaged because of issues with blood circulation (ischemic lesions), inflammation, degeneration, injuries (traumatic sequelae), or tumors or abnormal blood vessels (tumoral/vascular pathologies).
The brain MRI results can also be merged with a head CT scan to provide more detailed pictures. This might help your doctor figure out the best treatment plan for you.
Treatment Options for Holmes Tremor
Various medications are often used to manage certain health conditions. Some of the most commonly used drugs include levetiracetam, trihexyphenidyl, levodopa, dopamine agonists, anticholinergics, and topiramate. Levetiracetam and the anticholinergic drug trihexyphenidyl have been particularly successful in treating these conditions. Levodopa also has a reasonable success rate with about 54% response. Should these treatments not fully alleviate symptoms, other drugs such as clonazepam, bromocriptine, amantadine, biperiden, or botulinum toxin injections could be considered.
When medications are not as effective, surgical treatments can be another option. Stereotactic lesions, mainly at the thalamus (which is a part of your brain), have shown to bring about some improvements. However, the benefits may fade over time.
Another surgical method is Gamma knife thalamotomy, a precise form of radiation therapy, targeting a specific part of the thalamus with a very high dose of radiation. This treatment has shown partial results in improving the condition.
Deep Brain Stimulation (DBS) is another surgical option that involves electrically stimulating targeted areas in the brain via implanted electrodes. DBS can result in a notable clinical response. For instance, DBS at a region named GPi seems to better control resting tremors and overall tremor improvement.
There are several other potential targets for DBS that have shown positive single case improvements. It’s essential to be aware that stimulation in these areas is likely to be a lifelong requirement. If the system were removed after a few years, the patient’s symptoms could revert back to their pre-implantation state.
One more promising treatment under clinical trials is Focused Ultrasound. This non-invasive procedure uses high-intensity sound waves to target deep brain tissues and treat movement disorders and some types of tremors.
What else can Holmes Tremor be?
When a person experiences tremors, it could be due to a variety of conditions. Some of these include:
- Essential tremor: This is the most common type of tremor that happens during activity, usually affecting both sides of the body. It typically has a frequency of 4 to 12 Hz and often starts between the ages of 60 and 70.
- Intention tremor: This type of tremor happens when you’re moving purposefully.
- Parkinson’s disease tremor: This is the most common type of resting tremor, which means it happens when your muscles are still and relaxed.
- Orthostatic tremor: This typically occurs in middle-aged or older adults and causes unsteadiness when standing. It is a 16 Hz tremor that affects the lower body.
- Physiological tremor: This is a natural tremor that does not interfere with everyday activities and ranges in frequency from 8 to 12 Hz.
- Cerebellar tremor: This typically has a low frequency below 5 Hz and doesn’t cause tremors when at rest.
- Functional tremor: This type of tremor has no physical cause that can be found and can present in different ways. It doesn’t respond to medication and can change in frequency. It may also lessen when the person is distracted.
It’s always important to get medical help if you’re experiencing tremors, as they could indicate a more serious underlying condition.
What to expect with Holmes Tremor
Deep Brain Stimulation (DBS) is a technique which provides significant improvement in controlling overall tremor, particularly in postural tremor, which is a shaking that occurs when you try to maintain a position against gravity. This improvement is observed to be better when the stimulation is done on areas of the brain called GPi, VOP, or VOA, compared to the traditional Vim area of the brain.
Possible Complications When Diagnosed with Holmes Tremor
Here are some potential issues that may arise:
- Difficulties with everyday tasks
- Complications from thalamotomy surgery including internal brain bleeding, weakness, abnormal muscle contractions, and problems with speech
- Complications from DBS surgery (Deep Brain Stimulation) like internal brain bleeding, weakness, infections from implanted foreign objects, and issues with the medical equipment maintenance
Preventing Holmes Tremor
Holmes tremor is a condition that can seriously impact a patient’s quality of life. It causes shaking during both rest and active movements, including maintaining posture. This happens in addition to the main condition that caused the tremor. At present, there’s no specific cure for Holmes tremor.
Certain medications such as levetiracetam, trihexyphenidyl, or levodopa, along with a surgical procedure called deep brain stimulation (DBS) have been used to help control the symptoms. But it’s important to note that these treatments don’t always work for everyone or completely abolish the tremor.
Initially, it’s suggested to try the mentioned medications to see if they help reduce the tremor. If they don’t give satisfactory results, DBS might be the next course of action. However, it’s essential for patients to understand that DBS might not completely eliminate the tremor, and it might involve stimulating multiple brain areas. Moreover, DBS will not improve the original neurological problems that led to the development of the tremor.
This clarity is crucial to avoid any false expectations from the treatment and ensure patients understand what can realistically be achieved through the procedure.
