Biomedical Engineering Reference
In-Depth Information
that is available as a result of the execution of a movement, such as vision,
proprioception, and audition (Schmidt and Lee 2005). In stroke survivors intrinsic
feedback mechanisms are often disturbed. By providing additional augmented
feedback from an external source in therapy, motor relearning can be enhanced
(van Vliet 2006).
Augmented feedback has the advantage of having the opportunity of incorpo-
rating several key elements (intensity, task-specificity, active-initiation, motivation,
and feedback) in an environment which can be adjusted to the personal abilities of
the patients. There are different possibilities of providing the desired augmented
feedback. Two main categories exist in providing augmented feedback: aspects
and types.
10.5.1 Aspects
An aspect of augmented feedback is defined as a more fundamental way of
providing feedback. Aspects of augmented feedback are related to information
about the movement performance or how many times the feedback is provided.
10.5.1.1 Nature
The nature of providing augmented feedback can be either knowledge of per-
formance (KP), or knowledge of results (KR). KP feedback concerns information
about the movement itself, such as information about the angle of the shoulder
during execution of a movement. KR feedback concerns information about the
outcome of the movement, such as information about the achievement of the goal.
Research in healthy subjects only gives inconclusive results about whether to
provide KP or KR feedback. Studies investigating the effect of KP or KR on motor
learning for stroke survivors are scarce (van Vliet 2006).
10.5.1.2 Timing
The timing of providing augmented feedback can be either concurrent or terminal.
Concurrent feedback is delivered during movement execution. Terminal feedback
can be given after completion of the movement.
In healthy subjects some research into the effectiveness of providing either
concurrent or terminal feedback is performed. It has been demonstrated that
the sooner after movement execution the augmented feedback was provided
the better (Schmidt 1997). On the other hand, when concurrent feedback was
provided during practice in healthy subjects, it enhanced the performance at that
moment. But in post measurement tests without concurrent feedback, it resulted
in performance decrements (Schmidt 1997). This indicates that caution needs to be
taken about when to provide feedback, as this could cause a reliance of the person
on the feedback during movement execution.
