Device to Augment Movements in Stroke Patients

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
Abstract
Problem Statement
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
Hinge and Worm Drive
Stepper Motor
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. 2007 verage/ASAMeeting/tb/5023.
• How Stepper Motors Work." Images Scientific
  Instruments. 2007. 22 Feb. 2008
  ml.
• Robotic Device Helps Stroke Patients Regain Hand
  Use." American Stroke Association Meeting (2007).
  9 Feb. 2007 verage/ASAMeeting/tb/5023.
• Chronic diseases and associated risk factors.
  Austrailian Institue of Health and Welfare
  (2008). 27 Apr. 2008 x.cfm
• Leading and Actual Causes of Death. About.com.
  (2004). 29 Apr. 2008 /ss/death_causes.htm
• High Resolution Images. National Institute of
  Aging (2007). 27Apr. 2008 mers/Resources/HighRes.htm
• 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.