Parkinson's disease and essential tremors are the two most prevalent neurodegenerative diseases. They cause pathological tremors affecting many of the general population. To suppress tremors that highly affect daily living, scientists, neurologists, and other medical doctors suggest pharmacotherapy, surgical interventions, and assistive devices to help patients achieve more independent life.
Essential tremor affects 5% of the population, while Parkinson’s disease tremor affects 1% of people over 60.
PD tremor appears at rest position while ET appears in action.
ET shows bimodal age of onset, peak is at 15 and 55 years old.
ET hand tremor can be suppressed by medications, surgical intervention, and lifestyle management.
A tremor is a rhythmic, involuntary movement that can affect different body parts. Neurodegenerative disorders, such as Parkinson’s disease (PD) and essential tremor (ET) are the most common that cause tremors. ET affects 5% of the population over 65 years old and is the most prevalent pathological tremor, while Parkinson’s disease tremor affects 1% of people over 60.
Most of the patients who suffer from tremors have difficulties performing the activities of daily living, and suffer from depression and other psychological conditions. Patients who come to treatment centers are often forced to quit their jobs and struggle to find suitable work.
What are the differences between ET and PD tremors?
It is important to differentiate the tremors of ET and PD because they have different pathophysiological mechanisms. A PD tremor appears when the body is supported and at rest. It occurs for 75% of PD patients with low (4 – 6 Hz) tremor frequency.
Moreover, PD patients can have an action tremor called a reemergent resting tremor that appears during voluntary muscle contraction. This type of tremor occurs when the sufferer shifts a part of their body into a new position. A reemergent tremor has a higher frequency than a tremor in a resting position.
ET is described as an action tremor present for at least three years and affects mostly upper limbs in about 95% of patients. Studies show bimodal age of onset. ET affects young and old age groups, where the peak is between 15 and 55 years old.
Children are affected similarly to adults, experiencing voice, head, leg, and rest tremors. However, none of the children in the study reported difficulties in daily activities, while in adult populations it is very common. Limb tremor frequency can be in the range of 8 – 12 Hz. Both upper limbs are affected by ET and mild-moderate asymmetry is common. Tandem walking and upper-extremity rest or intention tremor can be seen in advanced ET patients. ET is diagnosed when no other signs of other neurologic diseases (dystonia, ataxia, Parkinson's) can be seen.
Treatment of essential tremors
Firstly, essential tremor treatment starts with pharmacotherapy. Once drug therapy has been tried, surgical procedures may be performed. Most of the patients do not respond to drug therapies such as beta-blockers, anticonvulsants, and antipsychotics. Those who do respond might not have significant improvement.
Moreover, botulin toxin injections are recommended in medically refractory cases. Patients reported modest improvements during clinical trials when botulin toxin was injected, but function did not improve. However, when the injection location was prescribed individually the effect on activities of daily living was seen. Injections in the neck can have side effects: weakness, dysphagia, and breathing difficulties.
To reduce hand tremors surgical procedures are performed. One of the surgical interventions is deep brain stimulation (DBS). The studies showed that DBS offers significant improvement in the reduction of hand tremors 10 years after surgery. However, this intervention has side effects, such as dysarthria, disequilibrium, and skin infections.
Another surgical intervention is MRI-guided focused ultrasound. It is less invasive than DBS. The effect of this intervention diminishes within two years.
Lifestyle management can be a good tool to reduce tremor in daily activities. The use of weighted devices to reduce amplitude of shaking has some promising results. As technology improves essential tremor patients are able to use medical devices for treatment or alleviation of ET symptoms.
Tips for how to stop shaky hands
Tremors can be alleviated, and is very important to achieve this during the treatment process to help people with daily living. Some of the methods for alleviating rest and action tremor for Parkinson’s disease and essential tremor patients are as follows:
- ET patients can use weighted devices, such as a pen or computer mouse, to reduce the amplitude of shaking. However, a study reported that weighted devices did not reduce rest tremors in PD patients.
- Assistive devices which cause electrical muscle stimulation can reduce resting tremors for PD patients.
- Virtual Reality training has been shown to positively affect PD patients.
- Eccentric exercises for resting tremors - a study showed that upper limb eccentric exercises can reduce resting hand tremors, but not postural tremors for PD patients. Eccentric training can induce longitudinal muscle growth and improve strength.
Although there is no one-size-fits-all solution for those who suffer from tremors, there are treatments that can help. Make sure you speak to your primary care physician about all the options available to you.