Archive for category Hemianopsia
Left Homonymous hemianopia ways of meeting and talking to people
[BLOG] My CVI Journey – A blog dedicated to sharing ideas and inspiration for helping kiddos with Cortical Visual Impairment (CVI) improve vision
If you reside in Ontario and you suspect your child may have Cortical Visual Impairment (CVI) or another type of visual impairment, Ontario’s Blind-Low Vision Early Intervention Program is a program that could help your family.
When our daughter turned 2.5 months old and still wasn’t fixing or tracking, we started to suspect she was having a problem with her vision. We knew her actual eyes were fine because she’d had eye examinations done immediately after birth, but since she’d had […]
For the first several months of my daughter’s life, I found getting through tummy time to be a challenge on the best of days. Most of the time, my daughter hated it. She’d cry and scream from the minute I rolled her over onto her […]
When I first began learning about Cortical Visual Impairment (CVI), there’s one thing that was immediately clear: it was an absolute must that my husband and I include opportunities for visual stimulation throughout our daughter’s daily routine. Our daughter’s visual therapist encouraged us to do […]
[Abstract + References] Perspectives: Hemianopia—Toward Novel Treatment Options Based on Oscillatory Activity?
Stroke has become one of the main causes of visual impairment, with more than 15 million incidences of first-time strokes, per year, worldwide. One-third of stroke survivors exhibit visual impairment, and most of them will not fully recover. Some recovery is possible, but this usually happens in the first few weeks after a stroke.
Most of the rehabilitation options that are offered to patients are compensatory, such as optical aids or eye training. However, these techniques do not seem to provide a sufficient amount of improvement transferable to everyday life.
Based on the relatively recent idea that the visual system can actually recover from a chronic lesion, visual retraining protocols have emerged, sometimes even in combination with noninvasive brain stimulation (NIBS), to further boost plastic changes in the residual visual tracts and network.
The present article reviews the underlying mechanisms supporting visual retraining and describes the first clinical trials that applied NIBS combined with visual retraining. As a further perspective, it gathers the scientific evidence demonstrating the relevance of interregional functional synchronization of brain networks for visual field recovery, especially the causal role of α and γ oscillations in parieto-occipital regions.
Because transcranial alternating current stimulation (tACS) can induce frequency-specific entrainment and modulate spike timing–dependent plasticity, we present a new promising interventional approach, consisting of applying physiologically motivated tACS protocols based on multifocal cross-frequency brain stimulation of the visuoattentional network for visual field recovery.
[Abstract] Computer-Based Cognitive Rehabilitation in Patients with Visuospatial Neglect or Homonymous Hemianopia after Stroke
Unilateral lesions of visual cortex have the secondary consequence of suppressing visual circuits in the midbrain superior colliculus (SC), collectively producing blindness in contralesional space (“hemianopia”). Recent studies have demonstrated that SC visual responses and contralesional vision can be reinstated by a non‐invasive multisensory training procedure in which spatiotemporally concordant visual‐auditory pairs are repeatedly presented within the blind hemifield. Despite this recovery of visual responsiveness, the loss of visual cortex was expected to result in permanent deficits in that hemifield, especially when visual events in both hemifields compete for attention and access to the brain’s visuomotor circuitry. This was evaluated in the present study in a visual choice paradigm in which the two visual hemifields of recovered cats were simultaneously stimulated with equally‐valent visual targets. Surprisingly, the expected disparity was not found, and some animals even preferred stimuli presented in the previously blind hemifield. This preference persisted across multiple stimulus intensity levels and there was no indication that animals were less aware of cues in the previously blind hemifield than in its spared counterpart. Furthermore, when auditory cues were combined with visual cues, the enhanced performance they produced on a visual task was no greater in the normal than in the previously blind hemifield. These observations suggest that the multisensory rehabilitation paradigm revealed greater inherent visual information processing potential in the previously blind hemifield than was believed possible given the loss of visual cortex.
This video outlines the fitting and training process for The Peli Lens for Homonymous Hemianopsia
[Abstract] A qualitative exploration of the effect of visual field loss on daily life in home-dwelling stroke survivors
To explore the effect of visual field loss on the daily life of community-dwelling stroke survivors.
Semi-structured interviews were conducted with a non-purposive sample of 12 stroke survivors in their own homes. These were recorded, transcribed verbatim and analyzed with the framework method, using an inductive approach.
Two key analytical themes emerged. ‘Perception, experience and knowledge’ describes participant’s conflicted experience of having knowledge of their impaired vision but lacking perception of that visual field loss and operating under the assumption that they were viewing an intact visual scene when engaged in activities. Inability to recognize and deal with visual difficulties, and experiencing the consequences, contributed to their fear and loss of self-confidence. ‘Avoidance and adaptation’ were two typologies of participant response to visual field loss. Initially, all participants consciously avoided activities. Some later adapted to vision loss using self-directed head and eye scanning techniques.
via A qualitative exploration of the effect of visual field loss on daily life in home-dwelling stroke survivors – Christine Hazelton, Alex Pollock, Anne Taylor, Bridget Davis, Glyn Walsh, Marian C Brady, 2019
Watch a demonstration of assessing visual fields.
Read FREE related article: https://www.medbridgeeducation.com/h/…
Visual Deficits:Now You See It, Now You Don’t- A Clinical Pearl by Diane Powers Dirette, PhD, OTL
Visual deficits match many diagnoses and, if undetected, can be mistaken for other problems – e.g. sensory, motor, balance and cognitive deficits. It’s critical, therefore, that therapists know how to complete a basic visual screening and to interpret the results. For example, how can you tell homonymous hemianopia apart from unilateral inattention? The screening tools are virtually the same, but the screening results differ subtly.
Quick and easy simulation of homonymous hemianopia/homonymous hemianopsia. Great to show loved ones and caregivers the dramatic nature of stroke related visual field loss.
Right optic nerve lesion➡Blindness of Right eye
Left optic nerve lesion➡Blindness of left eye
Lateral part of optic chiasma lesion➡Binasal Hemianopia
Medial Part of optic chiasma lesion➡ Bitemporal Hemianopia
Right Optic tract lesion➡Left Homonymous Hemianopia