Reading Difficulty after Stroke: Ocular and non Ocular Causes

Abstract

Patients complaining of reading difficulty were mostly found to have visual impairment relating to low vision, eye movement or visual field loss. A small number were found to have non ocular causes of reading difficulty. Treatment or advice was possible for all patients with visual impairment.

Prevalence of ocular motor cranial nerve palsy and associations following stroke

“…6 However, it is unknown whether the convergence insufficiency preceded the stroke or occurred subsequent to the stroke and its effect on the ocular motor system. Given the rate at which reading impairment is noted in stroke populations, 19 it is important to check the presence of convergence insufficiency, as it is readily treatable. Equally it is important to check for saccadic abnormalities, nystagmus, and gaze defects because of the impact of poor saccadic control, oscillopsia, and defective gaze on activities of daily living and overall rehabilitation.…”

Neuro-ophthalmology Annual Review

“…Fifteen patients were diagnosed either with expressive or receptive aphasia without a visual cause, 8 had alexia, 109 had VF loss, 85 had eye movement abnormalities, 27 had low vision, and 39 had visual perceptual impairments (eg, visual inattention, visual agnosia and hallucinations, depth perception impairment, and achromatopsia). 115 In a study of 13 healthy subjects and 6 patients with left or bilateral occipital and/or temporal lesions, a correlation between mean reading time and the slope of the word-length effect was found in HVFDs. 116 Although there are functional differences between right and left HVFDs, in a study of 30 patients with HVFDs, there was no significant difference in collision avoidance between patients with left-and right-hemispheric lesions.…”

Vision Therapy as a Complementary Procedure During Neurotherapy

“…Stroke can also cause eye movement impairment that will result in reading problems. 10 There has apparently been little work examining the effects of brain injury on oculomotor function, although a study by Heitger et al 11 reported deficits in oculomotor control in 30 mild TBI patients compared to a noninjured control group. O'Shanick and O'Shanick 12 note that in TBI there may be disruptions of visual tracking, figure-ground awareness, visual organization and 3D perception.…”