interfacce cervello computer non invasive
TRANSCRIPT
BRINDISYS BRAIN-COMPUTER INTERFACE DEVICES TO SUPPORT
INDIVIDUAL AUTONOMY IN LOCKED-IN INDIVIDUALS
Febo Cincotti
adottato da
Goal of the project
• Development of an assistive system aimed at
preserving the communication capabilities of a
person who progressively loses his/her muscular
force, coping with his/her residual abilities.
In other words?
• Conventional assistive technologies must rely on a physical interaction mediated by muscular contraction
• Brain-Computer Interfaces (BCIs) detect the user’s intention by processing his/her brain activity
• We demonstrated that this technology can be used in an assistive device designed for persons with ALS
3
BRAIN COMPUTER
INTERFACES [4]
What a BCI is
“Brain–computer interfaces (BCI’s) give their users communication and
control channels that do not depend on the brain’s normal output
channels of peripheral nerves and muscles.”
“A BCI changes the electrophysiological signals from mere reflections of
CNS activity into the intended product of the activity: messages and
commands that act on the world”
Wolpaw et al. 2002, clinph
5
BCI: a logical scheme
Cognitive processing
(Intention)
Modification of
Brain Signals Signal Features
Classification
(Translation)
of Intent
appropriate feature extraction
appropriate feedback strategy
us
er
tra
inin
g
(le
arn
ing
)
co
mp
ute
r train
ing
(ca
libra
tion
)
Environment
[6]
Neuroelectrical features for BCIs
Rhythms Evoked potentials
Steady-state EPs Slow Cortical Potentials
[7]
P300 Potential
• The P300 is an event-related potential, dominating at parietal electrode sites.
• P300 follows unexpected sensory stimuli or stimuli that provide task related information
[8]
From Selllers & Donchin 2006, clinph
Oddball stimulus Stimuli
Brain responses
[9]
Relevant stimulus
10
P300 Speller
[11]
BCI application
or
BCI-powered application
?
BCI AS PART OF ASSISTIVE
TECHNOLOGIES [12]
Augmentative and Alternative Communication
• AT software running on PC
– Designed to be controlled through alternative input channels
[13]
Support to persons with ALS
• Access to the assistive device is customizable to
the residual motor functions of the user
– Touchpad, joystick, sensors, …
– … and a Brain Computer Interface
• Usable in the locked-in condition
[14]
System overview
[15]
Communication Environmental Control
Brindisys Applications
Virtual keyboard
Vocalize
fixed
sentences
Alarm bell Domotic
kit
TV/stereo
Control
Appliances
ON/OFF
• Scanning modality
– Switch devices
• Dwelling function
– Mouse emulator
• P300-based BCI
– Overlay approach
Universal accessibility
Hardware modules
[18]
The role of users
• Design
• Interim feedback
• Final assessment
[19]
User-centered design
“Please score the
limitations present in
communication aids that
you use ”
User Survey: Aids limitations
Participants:
7 End Users
13 Caregivers
20 Stakeholders
User-centered
design
0 1 2 3 4
Weight
Limited wearability
Esthetics
Difficulty of use
Size
Limited number of…
Slowness
Lack of customizability
Limitation
“Please rate the usefulness
of the following possible applications of assistive
technology for interpersonal communication,
environmental interaction and
personal autonomy”
User Survey: Functionalities
Participants:
7 End Users
13 Caregivers
20 Stakeholders
User-centered
design
0 1 2 3 4
Games
Chat
Opening Doors, awnings and shutters
Send SMS
Icons for communication
Web browsing
Temperature Control
Write text
Raise/lower bed or airmchair
Light Control
Alphanumeric character selection
TV/stereo Control
Alarm bell
Utility
At home with the Brindisys system
[22]
Evaluation: participants
8 persons with ALS were recruited from the ALS Centre of Sapienza University
of Rome (Policlinico Umberto I).
Participants
Sex Age ALSfrs-r Onset Conventional/Assistive input device
Subj1 M 55 13 spinal Automatic Scanning - 1 button
Subj2 M 59 37 spinal touch screen
Subj3 M 47 34 bulbar mouse
Subj4 F 75 38 bulbar mouse + keyboard
Subj5 F 72 34 bulbar mouse
Subj6 M 40 31 spinal Scanning - 2 buttons
Subj7 M 61 28 bulbar Scanning - 2 buttons
Subj8 F 72 41 bulbar mouse
Francesca Schettini
User-centered
design
The preliminary prototype was tested in
controlled experimental conditions
Evaluation
Prototype usability*
(effectiveness, efficiency and user satisfaction)
Conventional Assistive input
Communication Task
Environmental Control Task
P300 based BCI
Communication Task
Environmental Control Task
*(Riccio et al. 2011; Zickler et al. 2011)
User-centered
design
Results
Effectiveness Efficiency
User Satisfaction
70%
80%
90%
100%
ConventionalAssistive Input
P300 based BCI
Accuracy of selection
10
20
30
40
50
ConventionalAssistive Input
P300 based BCI
Workload (NASA-tlx)
6789
10
ConventionalAssistive Input
P300 based BCI
User Satisfaction (VAS 1-10)
60
70
80
90
100
Conventional AssistiveInput
P300 based BCI
System Usability Scale (SUS 0-100)
No statistical differences were detected
between the conventional/assistive
inputs and the BCI for Effectiveness,
Efficiency and User Satisfaction
CONCLUSIONS
[26]
What we already know
• An individual can learn to communicate in absence of muscular contraction
• This skill can be employed to establish a non-muscular alternative channel for the motor impaired.
• Real-time processing of biosignals provides a new tool for the neuroscience, with prospective implications for the clinical practice
• Only multidisciplinarity can boost research and development in the field of technological advancements for clinical applications
[27]
Open issues
• Does this skill persist in the late stages of ALS?
– Impaired eye movement
– decline in cognitive abilities, arousal and attention,
– extinction of goal-directed cognitive commands and intentions
• Limitations
– Speed
– Accuracy
– Usability
• Research platforms vs. commercial device
[28]
Acknowledgements
The Brindisys Consortium:
Sapienza Università di Roma • Dipartimento di Ingegneria
Informatica
• Dipartimento di Medicina e
Psichiatria
Università Magna Graecia di
Catanzaro
Associazione Crossing Dialogues
[29]
adottato da
IRCCS Fondazione Santa
Lucia di Roma
[30]
Thanks for your attention
[31]
NUOVE SLIDES DA INSERIRE NEL
CORPO DELLA PRESENTAZIONE: [32]
• The final prototype was re-
adapted according to the users’
feedback collected during the
preliminary evaluation.
• Indipendent home evaluation
What’s Next?
Automatized procedures for
configuration and calibration
Prototype features should
comply with user needs
Text predictor
Francesca Schettini
User-centered
design
BCIs to assist communication in ALS patients
[34]
Software applications
[35]
The prototype
• Hardware modules – Tablet
– BCI
– Domotic kit
• Software applications – Communication
• Speller, text to speech
• SMS
• …
– Domotic control • Appliances
• Remote control
• …
[36]
Experimentations with ALS users
[37] Conclusioni->