1. Device to Augment Movements in Stroke Patients
T. Fleming, M. Reagan, B. Rogers, T. Vovos
Client: Dr. Matt Jensen, M.D. Advisor: Dr. Paul Thompson, Ph.D
Problem Statement
Abstract
Electrical
Op amp, Analog Digital Converter, H- Bridge, Bipolar Stepper Motor
After stroke most patients regain movement but not full strength
Groups are working to augment movement of hand
Robotics are hypothesized to improve recovery of strength and or dexterity
The device should be a glove or mitten design that could sense and augment finger movements in stroke patients
More than 700,000 Americans suffer strokes annually, causing more serious long-term disabilities than any other disease1. Therefore, it is imperative that rehabilitation of stroke patients is efficient and successful. A common characteristic of post-stroke disability is loss of strength/sensation in the hand. It is hypothesized that robotics can be used to effectively augment this movement as well as improve the speed of recovery. In order to create such a device, there are a variety of approaches including the mechanical and electrical approach used in this design. The device is designed to move the hand in one movement as if it were hinged only at the knuckles. In order to take into account the amount of force a patient wants to apply with his/her hand, it is necessary to create a device that bases its movements off of varying pressure. This device includes a bladder that senses pressure and sends the signal to a microcontroller that determines the output for the stepper motor. The stepper motor moves the robotic hand. In the future, work will be done to improve mobility and mechanics, motor output, and the compactness of the device.
Design Constraints
Competing Projects
Background
The device should include the following items:
Sense when the patient is opening or closing their hand and augment this movement based on pressure
Able to be removed from hand with little to no work involved
A safety feature so the patients fingers are not broken
Be affordable and convenient for all stroke patients
HOWARD (Hand or Wrist Assisting Robotic Device)
The amount of damage done to the
brain varies
Physical debilities among
stroke patients vary from complete
inability to move muscles to
a mild deficit in mobility
When a person completes a physical task, blood flow increases in the locale of the brain responsible for that task
The brain transfers responsibility for a function from the trauma hemisphere to the healthy hemisphere
The majority of improvement in function occurs within the first three months after stroke
Patient therapy during this post-stroke time is extremely valuable
Example of Circuitry
Mechanical
Stepper Motor, Hinge, Worm Drive
Final Design
Bladder creates pressure output that drives stepper motor to move hinge on device
Statistics
Stepper Motor
Hinge and Worm Drive
Future Work
References
Improved mobility and mechanics: Increase the number of joints and mechanical complexity of the device to account for all the different movements a patient may want to make with his/her hand.
Sensory input/motor output: Electrical sensors will be incorporated that are sensitive and easy to calibrate.
Compact Size: integrate a smaller controller unit, battery, and mechanism.
Robotic Device Helps Stroke Patients Regain Hand Use." American Stroke Association Meeting (2007). 9 Feb <
“How Stepper Motors Work." Images Scientific Instruments Feb <
“Chronic diseases and associated risk factors.” Austrailian Institue of Health and Welfare (2008). 27 Apr <
“Leading and Actual Causes of Death.” About.com. (2004). 29 Apr <dying.about.com/od/causes/ss/death_causes.htm>
“High Resolution Images.” National Institute of Aging (2007). 27Apr <
Special thanks to Dr. Yen, Dr. Tompkins, Dr. Radwin, Dr. Webster, Rob Vovos, Ace Hardware
Stroke is the third leading cause of death in the US.
Stroke is the 10th leading cause of disability in the US.