Over 20 million people in the world are affected by movement disorders like Parkinson’s Disease (PD) and Essential Tremors (ET). Muhammad Ali an American professional boxer, activist, entertainer, poet, and philanthropist was suffering from Parkinson’s Disease. But he had punched back at Parkinson’s; battling the disorder with the same conviction that had made him a champion in and out of the ring.
A majority of this demographic has hand tremors that make it extremely difficult to perform common tasks such as eating, writing, brushing, which lead to social embarrassment, isolation, depression, etc. This makes it imperative for the development of an engineering solution to dampen hand tremors as medical solutions are generally temporary, ineffective, and costly.
Let us understand some of the reasons why designing such a mechanical device is arduous. It is important to note that the manifestation of the disorder drastically varies from person to person. Here are some of the characteristics of hand tremors:
1. Amplitude — how much the hand shakes; it could vary with time as well i.e. as the disorder progresses, the amplitude could increase
2. Frequency — how many shakes per second; varies from 3–14 Hz; those with PD typically have a lower frequency of hand tremors while ET comes with a slightly higher frequency; like the amplitude, the frequency could also vary as time progresses
3. Rhythmic or Non-rhythmic — PD and ET generally come with rhythmic hand tremors, but patients with Dystonia have non-rhythmic tremors
4. Direction — flexion-extension (up-down), pronation-supination (rotary), or a combination of both; ET prominently shows flexion and extension while PD majorly displays a combination
5. Symmetry — left and right side of the body; one part of the body can be differently affected from the other
6. Type of tremor — rest (when the limb is at rest) or action (when the limb is performing some action); rest tremor is more eminent with PD while action tremor is more eminent with ET
Hence, it is highly likely that coming up with a solution that fits all is immensely demanding. A good place to start could be working on dampening rhythmic hand tremors. The device may not be a solution for a small proportion of the aforementioned patients who have tremors in their entire arm (example: severe cases of PD) or those with non-rhythmic tremors.
