Cerebral (cortical) visual impairment in children
John Ravenscroft in The Routledge Handbook of Visual Impairment, 2019
A 10-year-old boy had had a heart infection when aged 3 (Gillen and Dutton, 2003). This caused indirect damage from bleeding into both posterior parietal lobes. He recovered well, but at age 10 could not read long words, follow text, write words in a line or copy, as print matched to his age had, for him, become too small and crowded. He was losing confidence. He often walked into people as if they were not there, or did not see moving objects like cars and impaired visual scanning was evident. Going down stairs and stepping off kerbs were difficult. Yet his optics, visual acuities, 3D and colour vision were normal. His visual fields could not be plotted because he could not simultaneously see the central and peripheral targets. He could not look at specified targets, but his eye movements to instructions like “look up”, were normal. He took a long time to find an item of clothing in a pile or on a patterned bed spread, or a pencil on a cluttered desk. His behaviours, symptoms, signs and brain imaging were consistent with the diagnosis of a variant of Balint syndrome, comprising inability to see more than one or two items at once at any moment, inaccurate visual guidance of reach and inability to move his eyes to a nominated target. Apparent impairment of his lower visual field, and inability to see fast-moving targets are typical accompaniments.
Clinical presentation and differential diagnosis of dementia in younger people
Marjolein de Vugt, Janet Carter in Understanding Young Onset Dementia, 2021
Posterior Cortical Atrophy (PCA) is the clinico-radiological syndrome that predominantly affects the occipital and parietal lobes, resulting in gradually progressive loss of higher visual functions, apraxia, and elements of the Gerstmann syndrome (Crutch et al., 2013; Crutch et al., 2017). Visual agnosia is a common presentation as well as the Balint syndrome, consisting of oculomotor apraxia, optic ataxia, and simultanagnosia (Moreaud, 2003). Typically, patients experience difficulties in reading, finding or placing objects, finding their way around, and driving. Variants presenting with difficulties in calculation and apraxia have been described. One or multiple visits to an ophthalmologist or optician are a commonly heard story of patients eventually visiting a memory clinic once it is suspected that the problem is not a primary eye issue. Incidentally, their clinical picture has been interpreted as a primary psychiatric disorder. This is particularly the case when the patient displays a Balint syndrome, as these patients cannot generate a visual overview of a space filled with objects and/or persons, whereas, on the other hand, they can identify details that catch their eyes. At onset, patients with PCA are mostly aware of their deficits, and when isolated disturbances in the visuospatial domain are present, they can remain independent in instrumental daily living activities. However, when the syndrome progresses, language and memory difficulties will emerge. These patients may benefit from support by occupational therapists or healthcare workers specialised in low vision. Although Alzheimer's disease is the most common underlying pathology, PCA is mostly considered a variant of Alzheimer's disease. Underlying corticobasal degeneration or Lewy body disease have also been described (Crutch et al., 2012).
Neuro-ophthalmology of movement disorders
Published in Expert Review of Ophthalmology, 2018
Visual hallucinations, one of the most prominent features of dementia with Lewy bodies (DLB), are present early in the course of the disease, even before the onset of motor symptoms or before the introduction of dopaminergic medications. Abnormal saccades with impaired velocity, amplitude, and latency have been described in patients with DLB [52]. Progressive Balint syndrome that manifested by the triad of oculomotor apraxia, optic ataxia (the inability to accurately reach for something one is looking at), simultagnosia (inability to perceive more than one object at a time) was reported in a patient with DLB, few years prior to the onset of dementia, parkinsonism, and hallucinations [53]. Balint syndrome is usually associated with bilateral parieto-occipital structural lesions or dysfunction, and hypoperfusion in those areas was revealed on 99Tc-ECD-SPECT imaging in the patient with DLB. Retinopathy with degenerative changes in photoreceptors and some other retinal layers without Lewy body accumulation were reported in postmortem eye examinations of DLB subjects [32].
Perioperative Vision Loss after Non-Ocular Surgery
Published in Seminars in Ophthalmology, 2018
Bart Chwalisz, Aubrey L. Gilbert, John W. Gittinger
Stroke can also be caused by hypoperfusion injury to the posterior watershed zone between the territories of the posterior and middle cerebral arteries,13 which typically occurs in the setting of massive blood loss and severe hypotension. In one study, 9% of strokes after CABG were in watershed areas.33 The clinical picture may involve partial vision loss and higher-order visual deficits, such as Balint syndrome, with features of asimultanagnosia, optic ataxia, and oculomotor apraxia. Delayed hypoperfusion strokes can be precipitated by postoperative blood loss or dehydration.31
Posterior cortical atrophy: clinical, neuroimaging, and neuropathological features
Published in Expert Review of Neurotherapeutics, 2023
John Best, Marianne Chapleau, Gil D. Rabinovici
Following Benson’s initial report, additional case series were published highlighting the clinical and radiographic features of PCA. Presenting symptoms classically include a variety of deficits in higher-order visual processing but can also include a number of nonvisual deficits which localize toposterior parietal regions. The most frequent visual symptoms are spatial perception deficits (i.e. where objects are in space) as well as object perception deficits (i.e. visual agnosia). Patients develop features of Gerstmann Syndrome, including agraphia (inability to write), acalculia (impaired mental calculations), finger agnosia (loss of ability to name and distinguish fingers), and right-left dissociation. Features of Balint syndrome, including oculomotor apraxia (impaired voluntary and purposeful eye movements), optic ataxia (inability to accurately reach toward an object under visual guidance), and simultanagnosia (the inability to simultaneously process and integrate multiple visual inputs), are also commonly present. Visual field defects are often detected, especially when formally assessed with perimetry. Function in other cognitive domains is generally preserved until more advanced stages of the disease, although visual memory can be impacted early in the disease course [2]. The syndrome’s name is derived from the profound atrophy, hypometabolism and hypoperfusion of parieto-occipital and parieto-temporal visual association cortices noted on structural and functional brain imaging [1,3]. Neuropathologic series of patients diagnosed with PCA during life and followed to autopsy have found that the PCA clinical syndrome is most frequently associated with Alzheimer’s disease (AD) neuropathologic changes and is therefore sometimes referred to as the ‘visual variant of AD’ The most common alternative pathologies are Lewy Body Disease and corticobasal degeneration [4,5]. Prion disease has been described with an initial PCA presentation but is exceedingly rare [4].
Related Knowledge Centers
- Simultanagnosia
- Oculomotor Apraxia
- Ataxia
- Dysmetria
- Optometry
- Ophthalmology
- Therapist
- Parietal Lobe
- Stroke
- Alzheimer's Disease