Related Experiment Video
Updated: May 30, 2026

SECONDs Administration Guidelines: A Fast Tool to Assess Consciousness in Brain-injured Patients
Published on: February 6, 2021
Visual pursuit: within-day variability in the severe disorder of consciousness
Antonio Candelieri1, Maria Daniela Cortese, Giuliano Dolce
1S. Anna Institute and Research in Advanced Neurorehabilitation (RAN), Crotone, University of Calabria, Cosenza, Italy.
Abstract:
Visual pursuit marks substantial recuperation from a vegetative state and evolution into a minimally-conscious state, but its incidence in different studies suggests some unreliability in contrast with its established prognostic relevance. Subjects in vegetative (n=9) or minimally-conscious (n=13) states were tested for visual pursuit 6 times/day (9:30, 10:30, and 11:30 am, and 2:00, 3:00, and 4.00 pm, for a total of 132 determinations). Visual pursuit was observed at all testing times in 8 minimally-conscious patients, and never in 5 subjects in a vegetative state. Its incidence per subject ranged from 50-100% of testing times in the minimally-conscious state (83±23%), and 0-33% in a vegetative state (7%±12), with spontaneous fluctuations during the day and maximal levels at 10.30 am and 3.00 pm, and was never observed at the post-prandial time point (2:00 pm). The overall chance of observing visual tracking at least once during the day was ∼33% in the vegetative state, whereas that of not observing it in the minimally-conscious state was ∼38%. These percentages are congruent with the reported misdiagnosis rate between the two conditions, and document spontaneous variability possibly related to circadian rhythms.
Related Concept Videos
Photoreceptors and Visual Pathways
High-Level and Low-Level Awareness
REM Sleep Behavior Disorder
RBD is significantly associated with...
Increased Intracranial Pressure l: Introduction
Perceptual Constancy
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
Increased Intracranial Pressure ll: Pathophysiology

