People who suffer from hand tremors have a lot of difficulties in their daily activities, starting with eating, dressing and writing. For this reason, collaboration between science and medicine is essential in order to develop devices that can help patients with hand tremors.
A variety of different technologies are used for suppression of tremors: robotic exoskeletons, soft exoskeletons, electrical stimulation neuroprosthesis, and afferent neuroprosthesis.
Scientific data and real-world evidence show that assistive devices can help reduce tremors related to Parkinson's disease and Essential Tremor.
In today’s world, people who suffer from hand tremor can eat with dignity, write more smoothly, dress themselves easier because of the assistive devices.
Technologies that can suppress tremors
In a review of wearable technologies which can suppress tremors, has shown a number of different devices and techniques, including robotic exoskeletons, soft exoskeletons, electrical stimulation neuroprosthesis, and afferent neuroprosthesis.
All of these devices have pros and cons for daily living or tremor suppression. For example, in robotic exoskeletons, the main aim was to apply force and inertia to the affected limb with different kinds of orthotic devices. The verdict on robotic exoskeletons showed high suppression capability but that they are not useful for daily activities.
A soft exoskeleton is more attractive than a robotic exoskeleton. Here, controllable and flexible actuators are used. The drawback of these devices is poor validation in suppressing tremors because only healthy subjects were tested. However soft exoskeletons have potential.
Electrical stimulation neuroprosthesis is based on the activation of tremorgenic or antagonist muscles to change dynamic behavior. The advantage of this system is increased wearability, however, it is not effective in all subjects and less effective than exoskeletons.
Afferent neuroprosthesis refers to a device connected to a person's neurological system. These can provide proprioceptive input through passive joint movements which can modulate tremors in patients who have Parkinson's Disease (PD) and also, and low-level electrical stimulation can modify the tremor frequency. This technology is less invasive and more tolerable than electrical stimulation, however, it is less effective than electrical stimulation neuroprosthesis.
Commercial devices for ET and PD tremor suppression
Cala Trio therapy
According to the manufacturers, Cala Trio therapy is for patients diagnosed with essential tremors and is a non-invasive medical device that can be worn on the wrist like a watch. The hand tremor is treated by gentle electrical stimulation applied to the wrist nerves. Cala Trio therapy is calibrated individually according to each patient's brain signal patterns. The scientific proof showed decreased tremors in doing a spiral drawing. The real-world evidence confirms scientific evidence with effective reduction of tremors and improvement in patient’s daily living. However, this device has contraindications for those who have implanted electrical medical devices, are diagnosed with epilepsy or seizure disorders, are pregnant women, and are on the treated wrist with diseased skin.
The creators of the Vilim ball suggest this device is for patients with Essential Tremors (ET) and Parkinson’s disease. This ball is handheld and the working principle is based on vibration therapy. The medical device Vilim ball can be adapted to each symptom individually. According to evidence as stated by the authors, 10 minutes of therapy can reduce hand tremors for a period of up to four hours. Scientific research showed local vibration effectiveness in the treatment and relief of symptoms of ET. The authors of the Vilim ball created the mobile application “Steady hands” for the evaluation of hand tremors.
As with all devices, the Vilim ball also has contraindications for use, such as pregnancy, acute thrombotic process, implants, acute inflammation of the locomotor system, fresh fractures in activated regions of the body, epilepsy, and rheumatoid arthritis. Both treatments help reduce hand tremors for ET and PD patients.
The difference between Cala Trio and the Vilim ball is operating principle. Cala Trio therapy is based on electrical stimulation to wrist nerves, while the VILIM ball uses vibration therapy. The choice depends on a sensation that patient wants to feel and contraindications of use.
Orthotics for daily activities
Readi Steadi glove
The Readi Steadi glove is an anti-tremor orthotic glove system that reduces action tremors and resting tremors. The glove system is based on weights to help dampen the tremor in the hands. The non-toxic weights are implemented into molded gloves. Moreover, Readi Stedi glove does not restrict motion and can be worn 24 hours a day, seven days a week. If the intensity of the tremor increases or subsides, the glove allows for easy adjustment. A few contraindications must be evaluated before use: recent shoulder, arm, or hand injury, unmanaged arthritis or swelling of arm or hand, a severe intolerance to moderate compression garments, acute auto-immune exacerbation, severe shoulder subluxation, dislocation and/or hemiplegia, and skin abrasions.
Steadiwear is a medical device and it looks like a glove without covering the fingers. It has a calibrator that can be adjusted to the patient’s tremor and a vibration absorber that shakes in the opposite direction to the patient’s tremor. Steadiwear was tested with patients who have essential tremors. Results showed improvement in the reduction of tremors. Steadiwear works most effectively for people with mild to moderate hand tremors.
Liftware Steady is a spoon that can help patients with hand tremors related to Parkinson’s disease or essential tremors. This spoon has attachments that include a soup spoon, everyday spoon, fork, and spork. The Liftware Steady spoon electronically stabilizes using Active Cancellation of Tremor technology, allowing the utensil to shake 70% less than the patient’s hand. According to a study the spoon is effective only for those patients who have mild-moderate essential tremors.
S’up Spoon is used for soft food. The spoon is designed with a deep cavity that stops spills when it’s tipped back. Moreover, the spoon’s handle is angled for better pick-up from a flat surface.
There are many others weighted utensils. Most of them help during light to moderate tremors.
It is very difficult to put on a shirt with buttons when your hands shake. However, there are magnetic buttons that make it easy to fasten the shirts. Moreover, magnetic button adaptors can be attached to the patient’s own set of shirts. Other tools improve dressing, such as Velcro closures implemented in pants, and Velcro closures on shoes. Strong and flexible Hickies laces can be installed in sport's shoes, so patients never have a deal with shoelaces again.
There are created other technologies in the progress of testing and/or commercialization, such as GyroGlove, Tremor’s glove and others.
Technologies and assistive devices that can help handle challenges caused by tremors can make people’s lives safer, increase their sense of independence, enable them to eat with dignity, participate in community life, write and do many other things that were difficult to do without assistive devices.