The main objective of the separate studies of this study is the evaluation of grasping performance when electrotactile or vibrotactile feedback is provided compared to the non-feedback and only visual feedback situation. The main question to be…
ID
Source
Brief title
Condition
- Other condition
- Congenital and hereditary disorders NEC
Synonym
Health condition
amputatie van de onderarm
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Study 1 - position feedback
The main study parameter of study 1 will be the performance in grasping tasks.
This performance will be expressed in the time needed to complete the grasping
task. During one task several objects with different sizes have to be grasped
and hold for 2 seconds. Because it will no longer be trial and error to reach
the correct hand position, it is hypothesized that feedback will lower the time
needed to complete a task. The percentage of incorrect hand positions and the
mean deviation from the desired end position are also a main study parameters,
because this describes the over- and undershoot of the grasping motion and
therefore the accuracy in the grasping task.
Study 2 - force feedback
The main study parameter of study 2 is the performance of a force control task
when holding an object, also expressed in the time needed to complete the task.
During the task, an object has to be grasped and hold, while the support of the
object will be removed. Errors made during the performance task are also the
main study parameter. For this study the errors are the number of object
slippages and the excess of force applied to hold the object.
Study 3 - combination of position and force feedback
As study 3 is the combination of the first two studies, the main study
parameters are also the combination of the study parameters of those studies,
namely the performance in the grasping and holding task, expressed in the time
needed, the percentage incorrect hand positions, the deviations from the
desired positions, the number of slipped objects and the excess of force
applied during grasping. The challenge of this third study is the combination
of the best options of the first two studies.
Study 4 - feedback for patients
The best options from the first three studies will be combined in one protocol
that will be evaluated on amputee patients or patients with a congenital
deficit to proof the working of the methods to provide feedback to possible
prosthesis users. The main study parameters will therefore be a combination of
the parameters of the first three studies, all related to the performance in a
grasping task.
Secondary outcome
A possible confounder for these studies can be the gender of the subjects,
because there may be some differences in psychophysical characteristics, like
the perception and localization of stimuli. Furthermore, the order of the
experiments can influence the performance, because the first experiments can
serve as a training period for the following experiments. The order of
experiments within one study will be randomized over the subject to cancel this
training effect in the overall outcome of the study. However, an increase in
performance caused by the training effect will be followed while measurements
are repeated during the experiment with the same conditions.
Background summary
An incomplete upper limb, due to amputation or a congenital cause, results in a
great level of disability. A prosthesis should be able to take over the
function of the missing hand, but in practice the mechanism of the human hand
is very complex and cannot even be approached by a prosthesis. The development
of externally powered (myoelectric) prostheses has improved the more natural
control of the prosthesis, but at the cost of a large amount of non-visual
feedback. The lack of sensory feedback is indicated as one of the most
important factors in prosthesis rejection. Feedback of the applied grasping
force and the position of the prosthesis hand/fingers is essential in
subconscious prosthesis control according to representative users. In current
prostheses, there still is some haptic information about loads and
proprioceptive information of spatial orientation available, but no artificial
feedback about force and position is available and users therefore completely
have to rely on visual information. This drastically impedes the functionality
of a prosthesis, because users have to continuously watch their prosthesis
while grasping an object. Possible methods to provide artificial feedback are
electrotactile or vibrotactile stimulation of the skin. However, these methods
have rarely been used in prosthesis applications before.
Early research on methods to provide the feedback have mainly used
electrotactile stimulation, but more recent research focuses on vibrotactile
stimulation. Three large research projects aiming for the development of
innovative forearm prostheses have experienced with vibrotactile stimulation to
provide grasping force feedback. Although their evaluations showed positive
results of the use of feedback, it is not being implemented in current
prostheses, likely because of the lacking investigation of the optimal
stimulation settings. Even less research is being performed on the application
of position feedback. By Mann et al. phantom sensations (perceived sensations
between stimulators) are used to provide vibrotactile feedback of the elbow
angle of a Boston arm prosthesis. By Prior et al. feedback on the level of hand
opening of a Utah arm prosthesis is provided by electrotactile stimulation.
They used one electrode to provide position feedback (by pulse rate modulation)
simultaneously with force feedback (pulse width modulation), which resulted to
be not possible. However, they showed an increase in the performance in
distinguishing object sizes when using a separate electrode for position
feedback.
Study objective
The main objective of the separate studies of this study is the evaluation of
grasping performance when electrotactile or vibrotactile feedback is provided
compared to the non-feedback and only visual feedback situation. The main
question to be answered is: Will grasping performance increase with artificial
feedback? Grasping performance is defined as the time needed to complete a
grasping and/or holding task and the number of errors made before reaching the
desired position or deviations in the necessary force level.
Futhermore, another objective of these studies is to find the optimal
stimulation settings to provide position feedback, force feedback and the
combination of both types. This will be derived from the grasping performance
during different feedback conditions. Within these conditions, at least the
stimulation mode (vibrotactile or electrotactile), stimulation patterns and
stimulator placements will be varied.
Study design
As the goal of the study is to compare the effect of feedback on grasping
performance, grasping performance will be compared between situations with and
without feedback. All subjects will experience all feedback conditions and
therefore the study design will be a mono center experimental study.
Intervention
All subjects will receive feedback about the position of the hand and/or the
gripping force of the hand through electrotactile and vibrotactile stimulation.
Study burden and risks
There are no serious risks involved in this study, but there might occur some
skin problems, like redness or other irritations, after prolonged stimulation.
Furthermore, electrotactile stimulation can provoke painful sensations,
especially when determining the pain threshold or when the stimulus intensity
has to be increased to oppose adaptation effects. These effects will be very
short in duration and will not induce long term problems. Furthermore, the time
needed to complete the total study (about 2 hours) may cause some mental burden
to the subjects.
Drienerlolaan 5
7522 NB Enschede
NL
Drienerlolaan 5
7522 NB Enschede
NL
Listed location countries
Age
Inclusion criteria
age between 18 and 65 years (healthy subjects and patients)
ability to control the experimental setup (healthy subjects and patients)
forearm stump of at least 10 cm. (patients)
Exclusion criteria
diminished sense of touch (healthy subjects)
experience with vibrotactile and electrotactile stimulation (healthy subjects and patients)
skin problems at the place of stimulation (healthy subjects and patients)
hypersensitivity of the skin of the stump (patients)
bilateral amputation or deficit (patients)
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL36189.044.11 |