IEEE Robotics & Automation Magazine - September 2010 - 29

Unlike robotic devices, traditional orthoses are tuned by experts
and cannot automatically modify the level or type of assistance
as the patient grows and his or her capabilities change. Robotic
orthoses are typically in the form of an exoskeleton, which
envelopes the relevant body part. They must allow free motion
of limbs while providing the required support. Most existing
robotic exoskeletons are research devices that focus on military
applications (e.g., to allow soldiers to carry heavy loads on their
backs) and rehabilitation in the clinic. However, these systems
are not yet inexpensive and reliable enough for use as orthoses
by patients.
Prosthesis is an artificial extension that replaces the functionality of a body part (typically lost by injury or congenital
defect) by fusing mechanical devices with human muscle, skeleton, and nervous systems. Existing commercial prosthetic
devices are very limited in capability (typically allowing only
opening/closing of a gripper) because they are signaled to
move purely mechanically or by electromyography (EMG),
which is the recording of muscle electrical activity in an intact
part of the body). Robotic prosthetic devices aim to more fully
emulate the missing limb or other body part through replication of many joints and limb segments (such as the 22 degrees
of freedom of the human hand) and seamless neural integration that provides intuitive control of the limb as well as touch
feedback to the wearer (Figure 3). The last few years have seen
great strides in fundamental technologies and neuroscience
that will lead to these advanced prostheses. Further robotics research is needed to vastly improve the functionality and affordability of prostheses.

' 2010 INTERACTIVE MOTION TECHNOLOGIES.

JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY AND
REHABILITATION INSTITUTE OF CHICAGO.

Robot-Assisted Recovery and Rehabilitation
Patients suffering from neuromuscular injuries or diseases often
benefit from neurorehabilitation. This process exploits the usedependent plasticity of the human neuromuscular system, in
which use alters the properties of neurons and muscles, including
the pattern of their connectivity, and thus their function. Sensory
motor therapy, in which a patient makes upper extremity or

lower extremity movements physically assisted (or resisted) by
a human therapist and/or robot, helps people relearn how to
move. This process is time-consuming and labor-intensive but
pays large dividends in terms of patient health-care costs and
return to productive labor. As an alternative to human-only
therapy, a robot has several key advantages: 1) after set up, the
robot can provide consistent, lengthy, and personalized therapy without tiring; 2) the robot can acquire data to provide an
objective quantification of recovery; and 3) the robot can implement therapy exercises not possible by a human therapist. There
are already significant clinical results from the use of robots to
retrain upper- and lower-limb movement abilities for individuals
who have had neurological injury, such as cerebral stroke. These
rehabilitation robots provide many different forms of mechanical
input, such as assisting, resisting, perturbing, and stretching, based
on the subject's real-time response. For example, the Massachusetts Institute of Technology (MIT)-Manus rehabilitation robot
(now a commercial product, Figure 4) showed improved recovery of both acute and chronic stroke patients. Another exciting
implication of sensory-motor therapy with robots is that they can
help neuroscientists improve their general understanding of brain
function. Through robot-based perturbations to the patient and
quantification of the response, robots can make useful stimulusresponse recordings.
In addition to providing mechanical/physical assistance in
rehabilitation, robots can also provide personalized monitoring, motivation, and coaching. SAR focuses on using sensory
data from wearable sensors, cameras, or other means of perceiving the user's state to provide the robot with information
that allows the machine to appropriately encourage and motivate sustained recovery exercises. Early work has demonstrated
such SARs in the stroke rehabilitation domain, and they are
being developed for other domains including traumatic brain
injury. In addition to long-term rehabilitation, these systems
also have the potential to impact health outcomes in shortterm convalescence where intensive regiments are prescribed.
For example, an early system was demonstrated in the cardiac
ward, encouraging and coaching patients to perform spirometry exercises ten times per hour. Such systems can serve not
only as force multipliers in heath-care delivery, providing
more care to more patients, but also as a means of delivering

Figure 3. An advanced prosthetic arm with targeted
reinnervation-based myoelectric control.
SEPTEMBER 2010

Figure 4. The InMotion 2.0 Shoulder Robot is a commercially
available rehabilitation robot.
IEEE Robotics & Automation Magazine

Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - September 2010