A new system for quantitative evaluation of infant gaze capabilities in a wide visual field.
BACKGROUND
The visual assessment of infants poses specific challenges: many techniques that are used on adults are based on the patient's response, and are not suitable for infants. Significant advances in the eye-tracking have made this assessment of infant visual capabilities easier, however, eye-tracking still requires the subject's collaboration, in most cases and thus limiting the application in infant research. Moreover, there is a lack of transferability to clinical practice, and thus it emerges the need for a new tool to measure the paradigms and explore the most common visual competences in a wide visual field. This work presents the design, development and preliminary testing of a new system for measuring infant's gaze in the wide visual field called CareToy C: CareToy for Clinics.


METHODS
The system is based on a commercial eye tracker (SmartEye) with six cameras running at 60 Hz, suitable for measuring an infant's gaze. In order to stimulate the infant visually and audibly, a mechanical structure has been designed to support five speakers and five screens at a specific distance (60 cm) and angle: one in the centre, two on the right-hand side and two on the left (at 30° and 60° respectively). Different tasks have been designed in order to evaluate the system capability to assess the infant's gaze movements during different conditions (such as gap, overlap or audio-visual paradigms). Nine healthy infants aged 4-10 months were assessed as they performed the visual tasks at random.


RESULTS
We developed a system able to measure infant's gaze in a wide visual field covering a total visual range of ±60° from the centre with an intermediate evaluation at ±30°. Moreover, the same system, thanks to different integrated software, was able to provide different visual paradigms (as gap, overlap and audio-visual) assessing and comparing different visual and multisensory sub-competencies. The proposed system endowed the integration of a commercial eye-tracker into a purposive setup in a smart and innovative way.


CONCLUSIONS
The proposed system is suitable for measuring and evaluating infant's gaze capabilities in a wide visual field, in order to provide quantitative data that can enrich the clinical assessment.
The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, Italy. a.pratesi@sssup.it.
Andrea
A
Pratesi
The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, Italy. f.cecchi@sssup.it.
Francesca
F
Cecchi
Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Viale del Tirreno 331, 56128, Calambrone, Pisa, Italy. e.beani@fsm.unipi.it.|Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy. e.beani@fsm.unipi.it.
Elena
E
Beani
Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Viale del Tirreno 331, 56128, Calambrone, Pisa, Italy. g.sgandurra@fsm.unipi.it.
Giuseppina
G
Sgandurra
Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Viale del Tirreno 331, 56128, Calambrone, Pisa, Italy. gcioni@fsm.unipi.it.|Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 67, 56125, Pisa, Italy. gcioni@fsm.unipi.it.
Giovanni
G
Cioni
The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, Italy. c.laschi@sssup.it.
Cecilia
C
Laschi
The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, Italy. p.dario@sssup.it.
Paolo
P
Dario
D001288:Attention; D004867:Equipment Design; D005133:Eye Movements; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D055595:Mechanical Phenomena; D012984:Software; D018511:Systems Integration; D013997:Time Factors; D014584:User-Computer Interface; D014794:Visual Fields