The present study aims to test the feasibility of evoking basic facial expressions, as standardly identified in psychological research, with surface FES (stimulation via electrodes placed on top of the skin) and percutaneous FES (stimulation via…
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Brief title
Condition
- Other condition
Synonym
Health condition
n/a; fundamental research that contributes knowledge to the development of assistive technology for people with severe face and body paralysis
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main study parameter is the accuracy of FES-induced facial expressions. The
accuracy will be accessed using a number of different measurements and
analyses, including 1) manual and computer-based analysis of video recordings
of subjects* facial movements during FES; 2) self-reported perceptual feedback
of subjects regarding what facial expression was induced and their certainty
estimates about it; 3) ratings of recognizability of FES-induced facial
expressions in processed video recordings by external observers; 4) whenever
possible, electromyography recordings tracking individual facial muscle
movements during FES application.
Secondary outcome
The secondary study parameters or endpoints consist of stimulation parameters,
effects of inter-subject variability and the relationship between individual
facial muscles and wholistic facial expressions.
Background summary
Communication is an integral part of being a human. Communication means 1) the
transfer of conceptual information, or meaning, conveyed verbally or visually,
and 2) the transfer of affective information, or emotion, conveyed by
connotation (e.g., usage of positively or negatively loaded words), prosody
(rhythm, tone, pitch, and volume of the voice), and non-verbal communication
signals (e.g., facial expressions, posture, gestures, eye contact, spatial
distance, and physical touch). Unfortunately, individuals with severe facial
and whole-body paralysis are unable to use their facial expressions, body
language and even speech for communication. State-of-the-art Augmentative and
Alternative Communication (AAC) technology, including communication boards,
motion tracking devices and Brain-Computer Interfaces (BCIs), generally focuses
on restoring people*s ability to transfer conceptual information. The transfer
of affective information via AAC technology has so far been limited to words
with positive and negative connotations, for example, reflecting people*s
emotional state. It has not been possible for individuals with severe facial or
whole-body paralysis to use prosody and non-verbal communication signals to
convey emotion.
A potential technology that could make non-verbal communication of affective
information possible could detect a user*s intention to move their face, for
example, for producing a facial expression, bypass impaired motor pathways and
trigger external functional electrical stimulation (FES) of facial nerves to
activate target facial muscles and thereby induce the intended facial
expression on the user*s own face. Such a technology would constitute a *BCI-
FES neuroprosthesis* for restoring facial expressions thereby enabling
naturalistic communication of person*s emotions.
So far, it has been shown that intended distinct facial expressions can be
detected in neural activity for a potential use in BCI, and that FES applied on
individual facial nerves can lead to inducing individual facial movements of
the mouth, eye, forehead, and cheeks. It remains unclear whether wholistic
facial expressions that require simultaneous stimulation of multiple facial
sites can be induced with FES. It is also unclear to what extend the accuracy
of FES-evoked facial expressions may differ between FES setups (surface FES
with electrodes placed on top of the skin versus percutaneous FES with needles
piercing the skin). Overall, more research is needed to assess the potential of
BCI-FES to induce facial expressions for non-verbal communication.
Study objective
The present study aims to test the feasibility of evoking basic facial
expressions, as standardly identified in psychological research, with surface
FES (stimulation via electrodes placed on top of the skin) and percutaneous FES
(stimulation via needles placed under the skin in closer contact with target
nerve-muscle connections).
Study design
Two experiments and a survey study will be conducted: 1) Experiment I with
healthy participants and surface FES to induce individual facial muscle
movements and facial expressions. 2) Experiment II with patients who undergo a
brainstem surgery or a neuromuscular conflict surgery, during which
percutaneous FES is used for clinical purposes. During that time, an additional
FES session for research will be conducted to induce facial expressions. 3) a
Survey study will be conducted with a new group of healthy participants (not
part of Experiment I) to collect recognizability ratings of FES-induced facial
expressions captured with video recordings during Experiments I and II.
Study burden and risks
All hardware used for stimulation is CE-marked or MTKF-approved, and is safe to
use for the purpose of the present study. In Experiment I, the risk level is
minimal since standard stimulation protocols based on published literature
(e.g., Ilves et al., 2019 and Volk et al., 2020) will be followed to ensure
subjects* well-being and comfort during FES recordings. Besides, in Experiment
I, detailed monitoring of subjects* level of discomfort and pain will be
carried out. For Experiment II, clinical and research FES are applied while the
participants are under general anesthesia. The risk level is this case is
minimal since stimulation parameters are defined in consultation with the
neurosurgeon and neurophysiologist and follow the settings of the clinical
procedure. There is no immediate benefit to the subjects as the study aims to
gain scientific knowledge that in the long term can be applied to develop
assistive technology for individuals with severe facial and/or whole-body
paralysis.
Heidelberglaan 100
Utrecht 3584 CX
NL
Heidelberglaan 100
Utrecht 3584 CX
NL
Listed location countries
Age
Inclusion criteria
Experiment I with healthy volunteers:
• Age 18 years and higher
Experiment II with patient participants:
• Age 18 years and higher
• A clinical indication for undergoing a surgery, such as a brainstem stroke or
a neurovascular conflict
Survey study with healthy volunteers:
• Age 18 years and higher
Exclusion criteria
Experiment I with healthy volunteers:
• A history of electrical stimulation on the face for clinical reasons
• Impairment in facial muscle movement
Experiment II with patient participants:
• Indication of longer than average (6 hours for brainstem surgery and 4 hours
for neurovascular conflict surgery) duration of the procedure (estimation by
the neurosurgeon).
• The neurosurgeon or neurophysiologist decides that a certain patient is not
eligible to participate in the study (e.g., for medical or surgical reasons).
• Reported function loss that prohibits the accurate performance of the
required tasks.
Survey study with healthy volunteers:
• Participation in Experiment I.
Design
Recruitment
Followed up by the following (possibly more current) registration
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Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL85351.041.23 |