RT Journal Article
SR Electronic
T1 Visual discrimination training improves Humphrey perimetry in chronic cortically induced blindness
JF Neurology
JO Neurology
FD Lippincott Williams & Wilkins
SP 1856
OP 1864
DO 10.1212/WNL.0000000000003921
VO 88
IS 19
A1 Matthew R. Cavanaugh
A1 Krystel R. Huxlin
YR 2017
UL http://n.neurology.org/content/88/19/1856.abstract
AB Objective: To assess if visual discrimination training improves performance on visual perimetry tests in chronic stroke patients with visual cortex involvement.Methods: 24-2 and 10-2 Humphrey visual fields were analyzed for 17 chronic cortically blind stroke patients prior to and following visual discrimination training, as well as in 5 untrained, cortically blind controls. Trained patients practiced direction discrimination, orientation discrimination, or both, at nonoverlapping, blind field locations. All pretraining and posttraining discrimination performance and Humphrey fields were collected with online eye tracking, ensuring gaze-contingent stimulus presentation.Results: Trained patients recovered ∼108 degrees2 of vision on average, while untrained patients spontaneously improved over an area of ∼16 degrees2. Improvement was not affected by patient age, time since lesion, size of initial deficit, or training type, but was proportional to the amount of training performed. Untrained patients counterbalanced their improvements with worsening of sensitivity over ∼9 degrees2 of their visual field. Worsening was minimal in trained patients. Finally, although discrimination performance improved at all trained locations, changes in Humphrey sensitivity occurred both within trained regions and beyond, extending over a larger area along the blind field border.Conclusions: In adults with chronic cortical visual impairment, the blind field border appears to have enhanced plastic potential, which can be recruited by gaze-controlled visual discrimination training to expand the visible field. Our findings underscore a critical need for future studies to measure the effects of vision restoration approaches on perimetry in larger cohorts of patients.ANOVA=analysis of variance; CB=cortically induced blindness; CI=confidence interval; dLGN=dorsal lateral geniculate nucleus; HVF=Humphrey visual field; PD=pattern deviation; PMD=perimetric mean deviation; STF=short term fluctuations; UCB=untrained cortically induced blindness