Assessment of Eye Movements in Stroke Patients and Closed-loop Intervention

Eye-movement Dynamics During Free Viewing as a Biomarker for Assessment of Visuospatial Functions and for Closed-loop Rehabilitation in Stroke

The current study evaluates first the assumption that eye-movements during free viewing behavior are potential biomarkers of visuospatial deficits in stroke population. Second, it assesses the feasibility of a novel visual exploration training to ameliorate visuospatial deficits, by exploiting an auditory biofeedback system coupled with online parsed fixations.

This study is divided into two parts concerning the diagnostic and treatment of visuospatial deficits in patients affected by unilateral stroke. Eye movements indices during free viewing of natural scenes will be correlated to the standard neuropsychological evaluation, describing the cognitive, motor and functional spectrum of patient status. Moreover, functional and structural neuroimaging will be exploited to identify neural correlates of patient eye movements characteristics. Ultimately, a subsample of randomly assigned participants, at the IRCCS San Camillo, will undergo a novel visual exploration training, in addition to the standard rehabilitation. This protocol consists of natural scene exploration guided by an auditory biofeedback system which tracks online parsed fixations. Concretely, the training maneuvers exploration toward salient regions of the presented image, as indicated by a normative sample. Changes in free viewing behavior, neuropsychological assessment and neuroimaging will be discussed compared to an active control group and a healthy sample.

Inclusion Criteria:

• Vigilant
• First unifocal ischemic or hemorragic stroke
• Presence of maximum two lacunae, clinically silent, smaller than 15 mm. in the structural MRI
• Evident symptoms in the visual, attentive, memory, motor or language domain supported by the radiological exam

Exclusion Criteria:

• Previous stroke history, visible at the radiological exam
• Multifocal deficit
• Incapacity to remain vigilant during the required assessments
• Claustrophobia and/or metallic objects which could prevent MRI acquisition
• Presence of other neurological, psychiatric or medical conditions which may undermine interpretation of behavioral and neuroimaging results