Biomedical Engineering Reference
In-Depth Information
Research to the effectiveness of providing either concurrent or terminal feed-
back for stroke survivors is scarce. Therefore more insight in the influence of the
timing of augmented feedback on motor learning for stroke survivors is necessary.
10.5.1.3 Frequency
The frequency of providing augmented feedback can be either summary or faded.
An example of summary feedback is when after every 10th trial feedback is
provided. An example of faded feedback is when feedback is provided in a certain
schedule, after the 5th, 15th, 30th trial and so on (Schmidt and Lee 2005). Several
studies in healthy subjects demonstrated that learning improved more when
augmented feedback with a faded scheme was provided, than when feedback after
every trial (summary) was provided (Wulf 1989, 1993, Winstein 1990). However,
research into motor learning in stroke survivors shows no favorable effect of either
summary or faded feedback (Winstein 1990).
10.5.2 Types
The type of augmented feedback reflects the source of feedback, which originates
from an external source providing extra information to the internal sensors (ears,
skin, and eyes) of the body.
10.5.2.1 Auditory Feedback
Auditory feedback can include verbal encouragements and sound beeps. Mostly
auditory feedback is provided by means of verbal encouragements by physiother-
apists in therapy (Molier 2009a).
Rehabilitation therapy for stroke survivors by means of auditory cueing has
shown to be beneficial. In a study of Whitall (2000) 14 patients trained by means
of bilateral rhythmic reaching and retrieving actions using a metronome to cue
the patients, also called BATRAC training. After 18 training sessions patients
increased on average three points on the Fugl-Meyer scale (Whitall 2000).
Furthermore, little is known about the effect of the different ways of providing
augmented auditory feedback in both healthy subjects and stroke survivors.
10.5.2.2 Sensory Feedback
Sensory feedback is widely used since the introduction of rehabilitation robotics.
It includes force, tactile and positional feedback about the executed movement.
Mostly sensory feedback is provided combined with different kinds of augmented
feedback, such as augmented visual feedback (Molier 2009a).
Research into the ability of stroke survivors to learn from solely augmented
sensory feedback in a robotic device is promising (Molier 2009b). In the study of
Molier (2009b) patients performed reach and retrieval movements over a prede-
fined path, see
Figure 10.2
.
When deviating from this path, sensory feedback was
provided to the shoulder and elbow joints by means of resistance. To determine
