Dynamic Vibration Absorber for Suppression of Tremor of Hand in Parkinson’s Diseases

1. Dynamic Vibration Absorber for Suppression of Tremor of Hand in Parkinson’s Diseases Zaidi Mohd Ripin, School of Mechanical Engineering, Universiti Sains Malaysia 16/12/2008

2. Parkinson’s disease • Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills, speech, and other functions. [1] [1] Jankovic J (April 2008). "Parkinson's disease: clinical features and diagnosis". J. Neurol. Neurosurg. Psychiatr.79 (4): 368–76.

3. Hashemi et al. (2004) proposed a tuned vibration absorber (TVA) on a two degrees of freedom hand-arm model. • Based on their studies, the vibration absorber was designed, tested both analytically and experimentally. • Experimental investigations indicated that optimum control performance was related to the position of the controller and the excitation frequency (varies from 2 to 10 Hz). • With a distance of 160 mm from the end of forearm, the TVA was found to have the best performance, and, for different tremor frequencies, the vibration of the experimental model was reduced by more than 80%. Vibration absorber Analytical model Vibration absorber Experimental model Hashemi, S.M., Golnaraghi, M.F., and Patla, A.E., (2004) “A Tuned Vibration Absorber (TVA) for Suppression of Rest Tremor in Parkinson’s Disease,” Journal of Medical & Biological Engineering & Computing. Vol. 41, pp. 61-70.

4. Cherian et al. (1996) contributes to model development of a five DOF biomechanical model, which represents the viscoelastic and inertia properties of human hand-arm. • They proposed a 0.5 kg flow divider attached to a 5 DOF hand-arm model. • The overall weighted acceleration of the hand decreased by 22%, while the forearm and the upper arm increases by 13% and 10% respectively. Flow divider Schematic of 5DOF hand-arm model with flow divider Cherian, T., Rakheja, S. and Bhat, R.B. (1996). An analytical investigation of an energy flow divider to attenuate hand-transmitted vibration. Journal of Industrial Ergonomics. 17:455-467.

5. Principle of a vibration absorber • A simple vibration absorber consists of a mass and a spring. • When a primary system is excited by a harmonic force, its vibration can be suspended by attaching a vibration absorber. An absorber attached to primary system Animation

6. The vibration absorber has been used in many application since it was invented in 1909. • Applications range from small handheld tools, to giant structures such as bridges to large moving structures, such as aircraft. The collapse of Tacoma Narrows Bridge

7. However, passive vibration absorber has their shortcomings, example: narrow band treatment. • The alternative to passive vibration absorbers is active vibration absorber. • An active vibration absorber has an active element U (the actuator). • Active vibration absorbers have higher effectiveness and can re-tuned via their electronics/software (manually or automatically). An active dynamic absorber/tuned mass damper

8. Hand-held gyroscopic device The device is held against the back side of the human hand to reduce or eliminate essential tremor or other tremor. driven by an electric motor with batteries mounted near the periphery of the gyroscope to enhance the gyroscopic action. Reference: United States Patent 5058571

10. Research Potential • Tremor quantification (magnitude, direction, parts (eg finger, hand, arm, elbow) • Modeling of tremor in hand-arm system (internal forces?, verification) : • Parametric studies : introduction of devices to the model , identify possible reduction, optimization • Design : drawing, detail components: PATENT • Prototype development and field testing

11. New Technology • Piezo-electric devices for gyroscopic motion – high speed ; low mass = acceptable inertia • Active DVA – gyro system coupled with accelerometer with feedback system to REACT • Form factor : Location (no bigger than wristwatch ; not to interfere with hand function)

12. New Technology • Piezo-electric devices for gyroscopic motion – high speed ; low mass = acceptable inertia • Active DVA – gyro system coupled with accelerometer with feedback system to REACT • Form factor : Location (no bigger than wristwatch ; not to interfere with hand function) EXTREMELY DIFFICULT TO REALIZE !

13. SKILLS • Medical – what can and cannot • Mechanical – to model, measure • Control - to solve • Leader – to inspire us and get the money

14. Thank you