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Annual Review of Neuroscience 2011Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere injuries and is characterized by both spatial and non-spatial... (Review)
Review
Unilateral spatial neglect is a common neurological syndrome following predominantly right hemisphere injuries and is characterized by both spatial and non-spatial deficits. Core spatial deficits involve mechanisms for saliency coding, spatial attention, and short-term memory and occur in conjunction with nonspatial deficits that involve reorienting, target detection, and arousal/vigilance. We argue that neglect is better explained by the dysfunction of distributed cortical networks for the control of attention than by structural damage of specific brain regions. Ventral lesions in right parietal, temporal, and frontal cortex that cause neglect directly impair nonspatial functions partly mediated by a ventral frontoparietal attention network. Structural damage in ventral cortex also induces physiological abnormalities of task-evoked activity and functional connectivity in a dorsal frontoparietal network that controls spatial attention. The anatomy and right hemisphere dominance of neglect follow from the anatomy and laterality of the ventral regions that interact with the dorsal attention network.
Topics: Animals; Attention; Functional Laterality; Humans; Neural Pathways; Perceptual Disorders
PubMed: 21692662
DOI: 10.1146/annurev-neuro-061010-113731 -
The Cochrane Database of Systematic... Nov 2022Perception is the ability to understand information from our senses. It allows us to experience and meaningfully interact with our environment. A stroke may impair... (Review)
Review
BACKGROUND
Perception is the ability to understand information from our senses. It allows us to experience and meaningfully interact with our environment. A stroke may impair perception in up to 70% of stroke survivors, leading to distress, increased dependence on others, and poorer quality of life. Interventions to address perceptual disorders may include assessment and screening, rehabilitation, non-invasive brain stimulation, pharmacological and surgical approaches.
OBJECTIVES
To assess the effectiveness of interventions aimed at perceptual disorders after stroke compared to no intervention or control (placebo, standard care, attention control), on measures of performance in activities of daily living. SEARCH METHODS: We searched the trials registers of the Cochrane Stroke Group, CENTRAL, MEDLINE, Embase, and three other databases to August 2021. We also searched trials and research registers, reference lists of studies, handsearched journals, and contacted authors.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) of adult stroke survivors with perceptual disorders. We defined perception as the specific mental functions of recognising and interpreting sensory stimuli and included hearing, taste, touch, smell, somatosensation, and vision. Our definition of perception excluded visual field deficits, neglect/inattention, and pain.
DATA COLLECTION AND ANALYSIS
One review author assessed titles, with two review authors independently screening abstracts and full-text articles for eligibility. One review author extracted, appraised, and entered data, which were checked by a second author. We assessed risk of bias (ROB) using the ROB-1 tool, and quality of evidence using GRADE. A stakeholder group, comprising stroke survivors, carers, and healthcare professionals, was involved in this review update.
MAIN RESULTS
We identified 18 eligible RCTs involving 541 participants. The trials addressed touch (three trials, 70 participants), somatosensory (seven trials, 196 participants) and visual perception disorders (seven trials, 225 participants), with one (50 participants) exploring mixed touch-somatosensory disorders. None addressed stroke-related hearing, taste, or smell perception disorders. All but one examined the effectiveness of rehabilitation interventions; the exception evaluated non-invasive brain stimulation. For our main comparison of active intervention versus no treatment or control, one trial reported our primary outcome of performance in activities of daily living (ADL): Somatosensory disorders: one trial (24 participants) compared an intervention with a control intervention and reported an ADL measure. Touch perception disorder: no trials measuring ADL compared an intervention with no treatment or with a control intervention. Visual perception disorders: no trials measuring ADL compared an intervention with no treatment or control. In addition, six trials reported ADL outcomes in a comparison of active intervention versus active intervention, relating to somatosensation (three trials), touch (one trial) and vision (two trials). AUTHORS' CONCLUSIONS: Following a detailed, systematic search, we identified limited RCT evidence of the effectiveness of interventions for perceptual disorders following stroke. There is insufficient evidence to support or refute the suggestion that perceptual interventions are effective. More high-quality trials of interventions for perceptual disorders in stroke are needed. They should recruit sufficient participant numbers, include a 'usual care' comparison, and measure longer-term functional outcomes, at time points beyond the initial intervention period. People with impaired perception following a stroke should continue to receive neurorehabilitation according to clinical guidelines.
Topics: Adult; Humans; Activities of Daily Living; Perceptual Disorders; Stroke; Stroke Rehabilitation; Vision Disorders; Randomized Controlled Trials as Topic
PubMed: 36326118
DOI: 10.1002/14651858.CD007039.pub3 -
Clinical & Experimental Optometry Nov 2018Traumatic brain injury (TBI) and its associated concussion are major causes of disability and death. All ages can be affected but children, young adults and the elderly... (Review)
Review
Traumatic brain injury (TBI) and its associated concussion are major causes of disability and death. All ages can be affected but children, young adults and the elderly are particularly susceptible. A decline in mortality has resulted in many more individuals living with a disability caused by TBI including those affecting vision. This review describes: (1) the major clinical and pathological features of TBI; (2) the visual signs and symptoms associated with the disorder; and (3) discusses the assessment of quality of life and visual rehabilitation of the patient. Defects in primary vision such as visual acuity and visual fields, eye movement including vergence, saccadic and smooth pursuit movements, and in more complex aspects of vision involving visual perception, motion vision ('akinopsia'), and visuo-spatial function have all been reported in TBI. Eye movement dysfunction may be an early sign of TBI. Hence, TBI can result in a variety of visual problems, many patients exhibiting multiple visual defects in combination with a decline in overall health. Patients with chronic dysfunction following TBI may require occupational, vestibular, cognitive and other forms of physical therapy. Such patients may also benefit from visual rehabilitation, including reading-related oculomotor training and the prescribing of spectacles with a variety of tints and prism combinations.
Topics: Aged; Brain Injuries, Traumatic; Child; Eye Movements; Humans; Perceptual Disorders; Vision Disorders; Visual Acuity; Visual Fields; Young Adult
PubMed: 29488253
DOI: 10.1111/cxo.12670 -
Current Opinion in Neurology Feb 2020Visual snow is considered a disorder of central visual processing resulting in a perturbed perception of constant bilateral whole-visual field flickering or pixelation.... (Review)
Review
PURPOSE OF REVIEW
Visual snow is considered a disorder of central visual processing resulting in a perturbed perception of constant bilateral whole-visual field flickering or pixelation. When associated with additional visual symptoms, it is referred to as visual snow syndrome. Its pathophysiology remains elusive. This review highlights the visual snow literature focusing on recent clinical studies that add to our understanding of its clinical picture, pathophysiology, and treatment.
RECENT FINDINGS
Clinical characterization of visual snow syndrome is evolving, including a suggested modification of diagnostic criteria. Regarding pathophysiology, two recent studies tested the hypothesis of dysfunctional visual processing and occipital cortex hyperexcitability using electrophysiology. Likewise, advanced functional imaging shows promise to allow further insights into disease mechanisms. A retrospective study now provides Class IV evidence for a possible benefit of lamotrigine in a minority of patients.
SUMMARY
Scientific understanding of visual snow syndrome is growing. Major challenges remain the subjective nature of the disease, its overlap with migraine, and the lack of quantifiable outcome measures, which are necessary for clinical trials. In that context, refined perceptual assessment, objective electrophysiological parameters, as well as advanced functional brain imaging studies, are promising tools in the pipeline.
Topics: Brain; Functional Neuroimaging; Humans; Perceptual Disorders; Retrospective Studies; Vision Disorders; Visual Perception
PubMed: 31714263
DOI: 10.1097/WCO.0000000000000768 -
Continuum (Minneapolis, Minn.) Dec 2021Up to 80% of survivors of right brain stroke leave acute care without being diagnosed with a major invisible disability. Studies indicate that a generic cognitive... (Review)
Review
PURPOSE OF REVIEW
Up to 80% of survivors of right brain stroke leave acute care without being diagnosed with a major invisible disability. Studies indicate that a generic cognitive neurologic evaluation does not reliably detect spatial neglect, nor does it identify unawareness of deficit after right brain stroke; this article reviews the symptoms, clinical presentation, and management of these two cognitive disorders occurring after right brain stroke.
RECENT FINDINGS
Stroke and occupational therapy practice guidelines stress a quality standard for spatial neglect assessment and treatment to reduce adverse outcomes for patients, their families, and society. Neurologists may attribute poor outcomes associated with spatial neglect to stroke severity. However, people with spatial neglect are half as likely to return to home and community, have one-third the community mobility, and require 3 times as much caregiver supervision compared with similar stroke survivors. Multiple randomized trials support a feasible first-line rehabilitation approach for spatial neglect: prism adaptation therapy; more than 20 studies reported that this treatment improves daily life independence. Evidence-based treatment of anosognosia is not as developed; however, treatment for this problem is also available.
SUMMARY
This article guides neurologists' assessment of right brain cognitive disorders and describes how to efficiently assemble and direct a treatment team to address spatial neglect and unawareness of deficit.
Topics: Agnosia; Brain; Humans; Perceptual Disorders; Stroke; Stroke Rehabilitation
PubMed: 34881729
DOI: 10.1212/CON.0000000000001076 -
Annals of Physical and Rehabilitation... Jun 2017Acquired spatial dyslexia is a reading disorder frequently occurring after left or right posterior brain lesions. This article describes several types of spatial... (Review)
Review
Acquired spatial dyslexia is a reading disorder frequently occurring after left or right posterior brain lesions. This article describes several types of spatial dyslexia with an attentional approach. After right posterior lesions, patients show left neglect dyslexia with errors on the left side of text, words, and non-words. The deficit is frequently associated with left unilateral spatial neglect. Severe left neglect dyslexia can be detected with unlimited exposure duration of words or non-words. Minor neglect dyslexia is detected with brief presentation of bilateral words, one in the left and one in the right visual field (phenomenon of contralesional extinction). Neglect dyslexia can be explained as a difficulty in orienting attention to the left side of verbal stimuli. With left posterior lesions, spatial dyslexia is also frequent but multiform. Right neglect dyslexia is frequent, but right unilateral spatial neglect is rare. Attentional dyslexia represents difficulty in selecting a stimulus, letter or word among other similar stimuli; it is a deficit of attentional selection, and the left hemisphere plays a crucial role in selection. Two other types of spatial dyslexia can be found after left posterior lesions: paradoxical ipsilesional extinction and stimulus-centred neglect dyslexia. Disconnections between left or right parietal attentional areas and the left temporal visual word form area could explain these deficits. Overall, a model of attention dissociating modulation, selection control, and selection positioning can help in understanding these reading disorders.
Topics: Attention; Brain Diseases; Dyslexia, Acquired; Functional Laterality; Humans; Perceptual Disorders; Space Perception; Visual Fields
PubMed: 26272419
DOI: 10.1016/j.rehab.2015.07.004 -
Practical Neurology Oct 2015The syndrome of visuospatial neglect is a common consequence of unilateral brain injury. It is most often associated with stroke and is more severe and persistent... (Review)
Review
The syndrome of visuospatial neglect is a common consequence of unilateral brain injury. It is most often associated with stroke and is more severe and persistent following right hemisphere damage, with reported frequencies in the acute stage of up to 80%. Neglect is primarily a disorder of attention whereby patients characteristically fail to orientate, to report or to respond to stimuli located on the contralesional side. Neglect is usually caused by large strokes in the middle cerebral artery territory and is heterogeneous, such that most patients do not manifest every feature of the syndrome. A number of treatments may improve neglect, but there is no widely accepted universal approach to therapy. Although most patients recover spontaneously, the evidence suggests that they continue to have significant cognitive impairments, particularly relating to attention.
Topics: Female; Humans; Male; Perceptual Disorders
PubMed: 26023203
DOI: 10.1136/practneurol-2015-001115 -
Stroke May 2022Perceptual disorders relating to hearing, smell, somatosensation, taste, touch, and vision commonly impair stroke survivors' ability to interpret sensory information,... (Review)
Review
Perceptual disorders relating to hearing, smell, somatosensation, taste, touch, and vision commonly impair stroke survivors' ability to interpret sensory information, impacting on their ability to interact with the world. We aimed to identify and summarize the existing evidence for perceptual disorder interventions poststroke and identify evidence gaps. We searched 13 electronic databases including MEDLINE and Embase and Grey literature and performed citation tracking. Two authors independently applied a priori-defined selection criteria; studies involving stroke survivors with perceptual impairments and interventions addressing those impairments were included. We extracted data on study design, population, perceptual disorders, interventions, and outcomes. Data were tabulated and synthesized narratively. Stroke survivors, carers, and clinicians were involved in agreeing definitions and organizing and interpreting data. From 91 869 records, 80 studies were identified (888 adults and 5 children); participant numbers were small (median, 3.5; range, 1-80), with a broad range of stroke types and time points. Primarily focused on vision (34/80, 42.5%) and somatosensation (28/80; 35.0%), included studies were often case reports (36/80; 45.0%) or randomized controlled trials (22/80; 27.5%). Rehabilitation approaches (78/93; 83.9%), primarily aimed to restore function, and were delivered by clinicians (30/78; 38.5%) or technology (28/78; 35.9%; including robotic interventions for somatosensory disorders). Pharmacological (6/93; 6.5%) and noninvasive brain stimulation (7/93; 7.5%) approaches were also evident. Intervention delivery was poorly reported, but most were delivered in hospital settings (56/93; 60.2%). Study outcomes failed to assess the transfer of training to daily life. Interventions for stroke-related perceptual disorders are underresearched, particularly for pediatric populations. Evidence gaps include interventions for disorders of hearing, taste, touch, and smell perception. Future studies must involve key stakeholders and report this fully. Optimization of intervention design, evaluation, and reporting is required, to support the development of effective, acceptable, and implementable interventions. Registration: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42019160270.
Topics: Adult; Caregivers; Child; Humans; Perceptual Disorders; Stroke; Stroke Rehabilitation; Survivors
PubMed: 35468001
DOI: 10.1161/STROKEAHA.121.035671 -
Journal of Binocular Vision and Ocular... 2019Amblyopia is a neurodevelopmental disorder of the visual system, as a result of discordant visual experience during infancy or early childhood. Because amblyopia is... (Review)
Review
Amblyopia is a neurodevelopmental disorder of the visual system, as a result of discordant visual experience during infancy or early childhood. Because amblyopia is typically defined as monocularly reduced visual acuity accompanied by one or more known amblyogenic factors, it is often assumed that the fellow eye is normal and sufficient for tasks like reading and eye-hand coordination. Recent scientific evidence of ocular motor, visual, and visuomotor deficits that are present with fellow eye monocular viewing and with binocular viewing calls this assumption into question. This clinical update reviews the research that has revealed fellow ocular motor and visual deficits and the effect that these deficits have on an amblyopic child's visuomotor and visuocognitive skills. We need to understand how to prevent and rehabilitate the effects of amblyopia not only on the nonpreferred eye but also on the fellow eye.
Topics: Amblyopia; Child; Diagnostic Techniques, Ophthalmological; Humans; Ocular Motility Disorders; Perceptual Disorders; Physical Examination; Psychomotor Performance; Vision, Binocular; Visual Acuity
PubMed: 31161888
DOI: 10.1080/2576117X.2019.1624440 -
Progress in Neurobiology Nov 2015Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the... (Review)
Review
Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what is currently known about sensory processing in ASD, how sensory function fits within contemporary models of ASD, and what is understood about the differences in the underlying neural processing of sensory and social communication observed between individuals with and without ASD. In addition to highlighting the sensory features associated with ASD, we also emphasize the importance of multisensory processing in building perceptual and cognitive representations, and how deficits in multisensory integration may also be a core characteristic of ASD.
Topics: Animals; Autism Spectrum Disorder; Brain; Humans; Perception; Perceptual Disorders
PubMed: 26455789
DOI: 10.1016/j.pneurobio.2015.09.007