Biomedical Engineering Reference
In-Depth Information
Figure 4.2
Finger range of motion (x-axis: angle at the Metacarpophalangeal (MCP) joint)
and force (y- axis: force at the fingertips) required to complete typical ADL. The white
square (thick outline) represents the performances of healthy subjects, in terms of maximal
extension/flexion movement and force, while the black square represents the limited
performances of poststroke subjects with mild impairments. Performances are based on
actual data from the participants of the research study presented in this chapter (7 chronic
stroke patients), while the range of motion and force required to complete the ADL are
empirical. Post-stroke subjects are unable to completely perform the selected activities.
These impairments are often linked and severely limit stroke survivors' ability
to performADL.
Figure 4.2
s
ummarizes data from stroke patients to illustrate how
limited they are in performing typical activities requiring hand movements such
as in typing, writing or opening a jar.
The principal challenge of hand rehabilitation after stroke is thus to restore
grasping function and hand-wrist coordination, which are required to manipulate
objects and essential for ADL. In addition, fine finger control should be addressed
as it plays a crucial role in tactile exploration, manipulation of small objects and
fine motor tasks such as handwriting. However, for the more severely impaired
subjects, hand rehabilitation has to begin by training hand opening and working
on overcoming flexor muscle synergies that prevent subjects from performing
almost any type of activity with their hand.
4.3 ROBOT-ASSISTED REHABILITATION OF HAND FUNCTION
Robotic devices developed for arm and, more recently, for wrist rehabilitation,
obtained promising results, suggesting that robot-assisted treatment may lead to
increased gain relative to traditional therapy, which motivates the development of
new devices dedicated to hand rehabilitation (Takahashi
et al.
(2008), Hesse
et al.
The HWARD (Takahashi
et al.
(2005)) and the GENTLE/G (Loureiro and
Harwin (2007)) are examples of actuated exoskeletons designed to train grasping
and releasing of objects, while the Gifu Haptic Interface (Kawasaki
et al.
(2007)) is
