Opposed attentional hemi-bias on a visuoconstructive task in children with severe hyperactivity versus severe inattention.

Twenty six empirical investigations have now established that children and adults with DSM-defined Attention deficit/Hyperactivity disorder (ADHD) of the Hyperactive type (ADHD-H) or, more commonly, Combined Hyperactive/Inattentive types (ADHD-C) manifest a small but significant visual attentional bias to the right side (left subclinical neglect), consistently suggesting the existence of a subtle right hemisphere dysfunction or hemispheric imbalance in hyperactive people. Only one research team has investigated and compared the DSM-defined Inattentive subtype (ADHD-I) to the Hyperactive subtype (ADHD-H), confirming that line bisection is biased to the right in ADHD-H and discovering that it is biased to the left in ADHD-I. We aimed to test whether a similar crossed double dissociation would extend to Rey's Complex Figure Copy Task (RCF-CT), a simple visuospatial-constructive task. Clinical files of 205 juvenile clients from 6 to 16 years of age from a neuropsychological private clinic specialized in ADHD were analysed. Extreme scores on the Connors-3 Hyperactivity vs Inattention Parent Rating scales associated, respectively, with significant rightward and significant leftward emplacement of the drawing on the page on the RCF-CT. These results replicate previous findings and extend the "energetics" model of hemispheric specialization.

Critical issue on the extinction and inattention subtest of NIHSS scale: an analysis on post-acute stroke patients attending inpatient rehabilitation.

OBJECTIVES: This study aims to evaluate the diagnostic performance of NIHSS extinction and inattention item, compared to the results of the Oxford Cognitive Screen (OCS) heart subtest. Additionally, the possible role of the NIHSS visual field subtest on the NIHSS extinction and inattention subtest performance is explored and discussed. METHODS: We analysed scores on NIHSS extinction and inattention subtest, NIHSS visual field subtest, and OCS heart subtest on a sample of 118 post-stroke patients. RESULTS: Compared to OCS heart subtest, the results on NIHSS extinction and inattention subtest showed an accuracy of 72.9% and a moderate agreement level (Cohen's kappa = 0.404). Furthermore, a decrease in NIHSS accuracy detecting neglect (61.1%) was observed in patients with pathological scores in NIHSS visual field item. CONCLUSIONS: Extreme caution is recommended for the diagnostic performance of extinction and inattention item of NIHSS. Signs of neglect may not be detected by NIHSS, and may be confused with visual field impairment. TRIAL REGISTRATION: This study refers to an observational study protocol submitted to ClinicalTrials.gov with identifier: NCT03968627 . The name of the registry is "Development of a National Protocol for Stroke Rehabilitation in a Multicenter Italian Institution" and the date of the registration is the 30th May 2019.

Visual perceptual deficits and their contribution to walking dysfunction in individuals with post-stroke visual neglect.

BACKGROUND: Unilateral spatial neglect (USN), a highly prevalent and disabling post-stroke deficit, severely affects functional mobility. Visual perceptual abilities (VPAs) are essential in activities involving mobility. However, whether and to what extent post-stroke USN affects VPAs and how they contribute to mobility impairments remains unclear. OBJECTIVES: To estimate the extent to which VPAs in left and right visual hemispaces are (1) affected in post-stroke USN; and (2) contribute to goal-directed locomotion. METHODS: Individuals with (USN+, n = 15) and without (USN-, n = 15) post-stroke USN and healthy controls (HC, n = 15) completed (1) psychophysical evaluation of contrast sensitivity, optic flow direction and coherence, and shape discrimination; and (2) goal-directed locomotion tasks. RESULTS: Higher discrimination thresholds were found for all VPAs in the USN+ group compared to USN- and HC groups (p < 0.05). Psychophysical tests showed high sensitivity in detecting deficits in individuals with a history of USN or with no USN on traditional assessments, and were found to be significantly correlated with goal-directed locomotor impairments. CONCLUSION: Deficits in VPAs may account for the functional difficulties experienced by individuals with post-stroke USN. Psychophysical tests used in the present study offer important advantages and can be implemented to enhance USN diagnostics and rehabilitation.

Effects of a robot intervention on visuospatial hemineglect in postacute stroke patients: a randomized controlled trial.

OBJECTIVE: To evaluate the effects of an intervention using the robot device PARO on visuospatial hemineglect and activities of daily living, and its acceptance during stroke rehabilitation. PARO is an interactive robotic toy with the appearance of a baby seal, which can move, produce sounds, and react to speech and touch. DESIGN: A randomized controlled trial. SETTING: Hospital for neurorehabilitation. SUBJECTS: Patients above 60 years old who have suffered their first stroke within the previous three months with left hemineglect (n = 39). INTERVENTIONS: The PARO group (n = 21) was exposed to PARO over a period of two weeks, three times per week. The participants of the control group (n = 18) were read to aloud. OUTCOME MEASURE: Visuospatial hemineglect was measured by a cancellation test and a Line Bisection Test, and independence in the activities of daily living was assessed by Scores of Independence Index for Neurological and Geriatric Rehabilitation (SINGER) test. The acceptance of PARO was also evaluated. Data were collected blinded at three times: baseline (T0), after two weeks of interventions (T1), and after additional two weeks as follow-up (T2). RESULTS: Improvement of hemineglect at T1 and T2 was significantly higher in the PARO group (T1: mean (SD) = 6.23 (3.81); T2: mean (SD) = 7.85 (3.68)) compared to the control group (T1: mean (SD) = 2.66 (4.19); T2: mean (SD) = 3.33 (4.16)) (T1: P < 0.05; T2: P < 0.05). CONCLUSION: The study showed that the use of the PARO is well accepted and can help to improve neglect symptoms in patients with subacute stroke.

Thalamic Lesions and Aphasia or Neglect.

PURPOSE OF REVIEW: When the thalamus is damaged, not only are there neurological symptoms such as sensory impairment, hemianopia, or motor control disorders, but there are also various neuropsychological symptoms. We discuss the basic anatomy and function of the thalamus followed by a discussion of thalamic aphasia and hemineglect. RECENT FINDINGS: Subcortical lesions in patients with hemineglect involved the anatomical network directly linked to the superior temporal gyrus. Furthermore, the pulvinar, part of the thalamus, may be associated with hemineglect. General linguistic tasks activated the thalami, depending on the difficulty, as well as the frontal and temporal lobes. The thalamus may play a role in language and be involved in the activation of cortical language areas, and in the linguistic integration function via verbal memory and semantic mechanisms. Thalamic lesions are associated with aphasia and hemineglect. It is possible the mechanisms and such neuropsychological may be different depending on the size and site of the thalamic lesion.

Rehabilitation of visuospatial neglect by prism adaptation: effects of a mild treatment regime. A randomised controlled trial.

Closely examining the effects, optimal regime and time window of prism adaptation (PA) promotes guidelines for effective rehabilitation practice. The effects of short-term repetitive PA on spatial neglect manifestations were evaluated in patients with heterogeneous post-stroke delays, using a digital Visuospatial Neglect Test Battery. Subsequently, potential differences in PA effects between acute, subacute or chronic neglect were explored. A multicentre randomised controlled trial was conducted in 43 right-hemisphere neglect patients. They were treated with a mild PA regime: seven sessions of experimental or placebo prism training over 7-12 days. The outcome measures were diverse neglect variables related to peripersonal navigation, visual extinction, visuospatial memory, bisection, cancellation, drawing and visual search. The treatment effects were assessed after a short and a long time interval. Two to 24 hours after PA, conventional effects were found for drawing and centred bisection, and novel effects for peripersonal visuospatial navigation, visual extinction, and non-motor memory (with caution). No effects were found for visual search times and cancellation. The assessments after three months were still indicative of PA benefits for navigational, drawing and memory functions. PA did not prove to be more effective in acute, subacute or chronic patients. The extension of effects is theoretically framed within the debate about the levels of cognitive processing that are impacted by PA. Clinical suggestions are formulated regarding PA implementation in neglect treatment.

Virtual reality treatment and assessments for post-stroke unilateral spatial neglect: A systematic literature review.

Unilateral spatial neglect (USN) is a highly prevalent post-stroke deficit. Currently, there is no gold standard USN assessment which encompasses the heterogeneity of this disorder and that is sensitive to detect mild deficits. Similarly, there is a limited number of high quality studies suggesting that conventional USN treatments are effective in improving functional outcomes and reducing disability. Virtual reality (VR) provides enhanced methods for USN assessment and treatment. To establish best-practice recommendations with respect to its use, it is necessary to appraise the existing evidence. This systematic review aimed to identify and appraise existing VR-based USN assessments; and to determine whether VR is more effective than conventional therapy. Assessment tools were critically appraised using standard criteria. The methodological quality of the treatment trials was rated by two authors. The level of evidence according to stage of recovery was determined. Findings were compiled into a VR-based USN Assessment and Treatment Toolkit (VR-ATT). Twenty-three studies were identified. The proposed VR tools augmented the conventional assessment strategies. However, most studies lacked analysis of psychometric properties. There is limited evidence that VR is more effective than conventional therapy in improving USN symptoms in patients with stroke. It was concluded that VR-ATT could facilitate identification and decision-making as to the appropriateness of VR-based USN assessments and treatments across the continuum of stroke care, but more evidence is required on treatment effectiveness.

Complexity vs. unity in unilateral spatial neglect.

Unilateral spatial neglect constitutes a heterogeneous syndrome characterized by two main entangled components: a contralesional bias of spatial attention orientation; and impaired building and/or exploration of mental representations of space. These two components are present in different subtypes of unilateral spatial neglect (visual, auditory, somatosensory, motor, allocentric, egocentric, personal, representational and productive manifestations). Detailed anatomical and clinical analyses of these conditions and their underlying disorders show the complexity of spatial cognitive deficits and the difficulty of proposing just one explanation. This complexity is in contrast, however, to the widely acknowledged effectiveness of rehabilitation of the various symptoms and subtypes of unilateral spatial neglect, exemplified in the case of prism adaptation. These common effects are reflections of the unity of the physiotherapeutic mechanisms behind the higher brain functions related to multisensory integration and spatial representations, whereas the paradoxical aspects of unilateral spatial neglect emphasize the need for a greater understanding of spatial cognitive disorders.

Not Just Language: Persisting Lateralized Visuospatial Impairment after Left Hemisphere Stroke.

OBJECTIVES: Imbalances in spatial attention are most often associated with right hemisphere brain injury. This report assessed 25 chronic left hemisphere stroke patients for attentional bias. METHODS: Participants were evaluated with a computerized visual search task and a standardized neuropsychological assessment known as the Behavioral Inattention Test (BITC). Twenty age-matched controls were also tested. RESULTS: Although little to no attentional impairment was observed on the BITC, the computerized visual search task revealed statistically significant contralesional attentional impairment in the left hemisphere stroke group. Specifically, these participants required 208 ms more viewing time, on average, to reliably detect visual targets on the right side of the display compared to detection on the left side, while controls showed a difference of only 8 ms between the two sides. CONCLUSIONS: The observation of significant leftward visuospatial bias in this chronic stroke group provides further evidence that the left hemisphere also plays a role in the balance of visual attention across space. These results have implications for left hemisphere patients who are often not screened for visuospatial problems, as well as for theories of visual attention which have primarily emphasized the role of the right hemisphere. (JINS, 2016, 22, 695-704).

Spatial and temporal dynamics of visual search tasks distinguish subtypes of unilateral spatial neglect: Comparison of two cases with viewer-centered and stimulus-centered neglect.

We developed a computerised test to evaluate unilateral spatial neglect (USN) using a touchscreen display, and estimated the spatial and temporal patterns of visual search in USN patients. The results between a viewer-centered USN patient and a stimulus-centered USN patient were compared. Two right-brain-damaged patients with USN, a patient without USN, and 16 healthy subjects performed a simple cancellation test, the circle test, a visuomotor search test, and a visual search test. According to the results of the circle test, one USN patient had stimulus-centered neglect and a one had viewer-centered neglect. The spatial and temporal patterns of these two USN patients were compared. The spatial and temporal patterns of cancellation were different in the stimulus-centered USN patient and the viewer-centered USN patient. The viewer-centered USN patient completed the simple cancellation task, but paused when transferring from the right side to the left side of the display. Unexpectedly, this patient did not exhibit rightward attention bias on the visuomotor and visual search tests, but the stimulus-centered USN patient did. The computer-based assessment system provided information on the dynamic visual search strategy of patients with USN. The spatial and temporal pattern of cancellation and visual search were different across the two patients with different subtypes of neglect.

Association between daily activities, process skills, and motor skills in community-dwelling patients after left hemiparetic stroke.

[Purpose] The purpose of this study was to evaluate the relationships between daily activities, information processing, and motor skills in individuals with hemineglect after having a left hemiparetic stroke. [Subjects and Methods] The instrumental activities of daily living of 35 patients (22 male and 13 female; age: 57.1 ± 16.9 years) with hemineglect after having a left hemiparetic stroke were assessed by using three clinical measurement tools, including activity card sorting, assessment of motor and process skills, and the modified Barthel Index. [Results] The results of the regression analysis indicated that the patients' processing skills in instrumental activities of daily living after having a left hemiparetic stroke were reduced. Participation in leisure and social activities was also affected as assessed by using the modified Barthel Index. [Conclusion] This study supports the clinical need for rehabilitation intervention after a left hemiparetic stroke to improve patients' processing skills and independence in performing activities of daily living.

Impact of post-stroke unilateral spatial neglect on goal-directed arm movements: systematic literature review.

BACKGROUND: Unilateral spatial neglect (USN), a highly prevalent post-stroke impairment, refers to one's inability to orient or respond to stimuli located in the contralesional visual hemispace. Unilateral spatial neglect has been shown to strongly affect motor performance in functional activities, including non-affected upper extremity (UE) movements. To date, our understanding of the effects of USN on goal-directed UE movements is limited and comparing performance of individuals post-stroke with and without USN is required. OBJECTIVE: To determine, in individuals with stroke, how does the presence of USN, in comparison to the absence of USN, impacts different types of goal-directed movements of the non-affected UE. METHODS: The present review approach consisted of a comprehensive literature search, an assessment of the quality of the selected studies and qualitative data analysis. RESULTS: A total of 20 studies of moderate to high quality were selected. The USN-specific impairments were found in tasks that required a perceptual, memory-guided or delayed actions, and fewer impairments were found in tasks that required an immediate action to a predefined target. CONCLUSION: The results indicate that USN contributes to deficits observed in action execution with the non-effected UE that requires greater perceptual demands.

Transient Ipsilateral Hemineglect Following Brain Laser Ablation in Patient with Focal Cortical Dysplasia.

Sensory integration is the province of the parietal lobe. The non-dominant hemisphere is responsible for both body sides, while the dominant hemisphere is responsible for the contralateral hemi-body. Furthermore, the posterior cingulate cortex (PCC) participates in a network involved in spatial orientation, attention, and spatial and episodic memory. Laser interstitial thermotherapy (LiTT) is a minimally invasive surgery for focal drug-resistant epilepsy (DRE) that can target deeper brain regions, and thus, region-specific symptoms can emerge. Here, we present an 18-year-old right-handed male with focal DRE who experienced seizures characterized by sensations of déjà vu, staring spells, and language disruption. A comprehensive evaluation localized the seizure focus and revealed a probable focal cortical dysplasia (FCD) in the left posterior cingulate gyrus. The patient underwent uneventful LiTT of the identified lesion. Post-operatively, he developed transient ipsilateral spatial neglect and contralateral sensory loss, as well as acalculia. His sensory symptoms gradually improved after the surgery, and he remained seizure-free after the intervention for at least 10 months (until the time of this writing). This rare case of ipsilateral spatial and visual hemineglect post-LiTT in epilepsy underscores the importance of recognizing atypical neurosurgical outcomes and considering individual variations in brain anatomy and function. Understanding the dynamics of cortical connectivity and handedness, particularly in pediatric epilepsy, may be crucial in anticipating and managing neurocognitive effects following epilepsy surgery.

Hypoglycemic hemineglect a stroke mimic.

Acute hypoglycemia may mimic acute ischemic stroke, but to our knowledge this has never been reported as transient hemineglect syndrome. We present a 60-year-old male with known diabetes mellitus who was brought to the hospital as a stroke alert. The patient had undetectable glucose levels upon arrival of emergency medical services (EMS), therefore hypertonic glucose was given. On our assessment in the emergency department (ED)he turned his head to the right side, looking to the right to answer questions when addressed on his left side. The extinction and neglect assessment revealed left-sided extinction on double tactile and visual stimulation. CT perfusion of the brain showed a decreased perfusion in the right cortical area. Given the unclear last known normal, urgent brain magnetic resonance imaging (MRI) was performed; stroke was excluded. The patient was admitted to the Intensive Care Unit where glucose was closely monitored. Electroencephalogram showed absence of seizure or postictal activity. The following morning, the patient returned to baseline and was able to recall the event. The episode was attributed to the severe hypoglycemia because of a recent medication change.

Study of attentional deficits (unilateral spatial neglect) in Moroccan adolescents attending school-Rabat Sale Kenitra region.

Objectives: Attention is an essential part of cognitive functions for all learning in the school environment. The screening of attentional deficits constitutes an important field of research, given its relationship with other cognitive functions and the neurocognitive profiling of Moroccan adolescents in school. Materials and Methods: A study was conducted over 3 months. A comparative and predictive method is used, the Bells test, to assess the state of neglect of these students, as well as the detection of attention deficit. Results: Two hundred and fifty students participated, including 152 girls [60.4%] and 98 boys [39.6%], the average age is 16.77 ± 1.23 years, range: 14-21, divided into three school levels: Common core (TC) 27.6%, 1st-year baccalaureate 50.8%, and 2nd-year baccalaureate 21.6%. This study found that 18.4% of the students had attentional deficits and 4% had a unilateral spatial neglect pattern in young adolescents in school. Conclusion: The Bells Test is a useful screening tool to detect these attentional deficits. This implies that attentional disorders negatively influence the academic and motor performance of the subjects. This implies that attentional disorders negatively influence the academic and motor performance of the subjects and, therefore, increase the percentage of school failure.

Disruption of large-scale electrophysiological networks in stroke patients with visuospatial neglect.

Stroke frequently produces attentional dysfunctions including symptoms of hemispatial neglect, which is characterized by a breakdown of awareness for the contralesional hemispace. Recent studies with functional MRI (fMRI) suggest that hemineglect patients display abnormal intra- and interhemispheric functional connectivity. However, since stroke is a vascular disorder and fMRI signals remain sensitive to nonneuronal (i.e., vascular) coupling, more direct demonstrations of neural network dysfunction in hemispatial neglect are warranted. Here, we utilize electroencephalogram (EEG) source imaging to uncover differences in resting-state network organization between patients with right hemispheric stroke (N = 15) and age-matched, healthy controls (N = 27), and determine the relationship between hemineglect symptoms and brain network organization. We estimated intra- and interregional differences in cortical communication by calculating the spectral power and amplitude envelope correlations of narrow-band EEG oscillations. We first observed focal frequency-slowing within the right posterior cortical regions, reflected in relative delta/theta power increases and alpha/beta/gamma decreases. Secondly, nodes within the right temporal and parietal cortex consistently displayed anomalous intra- and interhemispheric coupling, stronger in delta and gamma bands, and weaker in theta, alpha, and beta bands. Finally, a significant association was observed between the severity of left-hemispace search deficits (e.g., cancellation test omissions) and reduced functional connectivity within the alpha and beta bands. In sum, our novel results validate the hypothesis of large-scale cortical network disruption following stroke and reinforce the proposal that abnormal brain oscillations may be intimately involved in the pathophysiology of visuospatial neglect.

Disorders of higher visual processing in patients with acquired brain injury.

BACKGROUND: Disorders of higher visual processing often impact patients with acquired brain injury. Even with treatment, these vision conditions can cause chronic challenges for patients. Understanding these conditions and their management can help improve functional independence and quality of life. OBJECTIVES: To discuss the various disorders of higher visual processing that result from acquired brain injury. Discussion to include classification, evaluation, and treatment techniques available to clinicians. METHODS: Peer reviewed journal articles were searched, primarily through PubMed. Articles spanning several decades were included in the review for historical context of these conditions, however an emphasis was placed on more recent publications for purposes of a discussion regarding clinical management of these conditions. RESULTS: Peer-reviewed articles and clinical trials from across several disciplines were included to frame a discussion of this varied group of conditions. CONCLUSION: Visual processing disorders have debilitating impacts on both the rehabilitation process as well as functional independence. Varied approaches are utilized in the treatment of these conditions with limited success. Understanding the benefits and limitations of both restorative and compensatory treatments will better help clinicians manage patients with these conditions.

Revisiting the attentional bias in the split brain.

Previous research has revealed a strong right bias in allocation of attention in split brain subjects, suggesting that a pathological attention bias occurs not only after unilateral (usually right-hemispheric) damage but also after functional disconnection of intact right-hemispheric areas involved in allocation of attention from those in the left hemisphere. Here, we investigated the laterality bias in spatial attention, as measured with the greyscales task, in two split-brain subjects (D.D.C. and D.D.V.) who had undergone complete callosotomy. The greyscales task requires participants to judge the darker (or brighter) of two left-right mirror-reversed luminance gradients under conditions of free viewing, and offers an efficient means of quantifying pathological attentional biases in patients with unilateral lesions. As predicted, the results of the two split-brain subjects revealed a pathological rightward bias in allocation of attention, suggesting strong dependence on a single hemisphere (the left) in spatial attention, which is opposite to what one expects from people with intact commissures, and is remarkable in that it occurs in free viewing. In that sense both split-brain patients are behaving as though the brain is indeed split, especially in D.D.C. who had undergone partial resection of the anterior commissure in addition to complete callosotomy, whereas the anterior commissure is still intact in D.D.V. The findings support the view that the commissural pathways play a significant role in integration of attentional processes across cerebral hemispheres.

"Sequential multimodality stimulation" for post-stroke-hemineglect: Feasibility and outcome in a pilot randomized controlled trial.

OBJECTIVE: To test the feasibility and efficacy of multimodality stimulation combined with motor tasking as a corrective strategy for hemineglect following right hemispheric ischemic strokes. MATERIAL AND METHODS: A prospective randomized controlled single blinded clinical trial was conducted over eighteen months from January 2017. All patients with right hemispheric ischemic strokes were screened for hemineglect and those fulfilling criteria were recruited and randomized. Patients under the therapy group (TG) received the intervention based on a structured protocol in addition to standard physiotherapy. The control group (CG) received standard physiotherapy alone. NIHSS, mRS and Neuropsychological test scores were recorded at different time points. The primary outcome measures (neuropsychological test scores) were compared between the two groups (Student's t-test to find out the difference in outcome measures) at one and three months post-stroke. RESULTS: Of the 14 patients recruited, data from 12 were available for analysis, 5 patients in TG and 7 in CG. There was a trend for better hemineglect and functional outcomes in TG. CONCLUSION: Multimodality stimulation, in addition to standard physiotherapy, is feasible and potentially results in better neurocognitive and functional recovery following right hemispheric ischemic strokes. However, larger studies are warranted to prove these preliminary observations beyond doubt.

Transcranial electric stimulation optimizes the balance of visual attention across space.

OBJECTIVE: Transcranial direct current stimulation (tDCS) provides a way to modulate spatial attention by enhancing the ratio of neural activity between the left and right hemispheres, with a potential benefit for the rehabilitation of visual neglect. METHODS: We tested the effect of bilateral tDCS in healthy individuals performing a visual detection task. This protocol consists in the positioning of the anode and cathode on mirror positions over the left and right parietal areas. The stimulation was repeated over three days to maximize the chance to observe a bias to the hemispace controlateral to the anode. RESULTS: Compared to a sham treatment, left anodal - right cathodal stimulation enhanced attention across the full range of space, since the first day with no build-up effect on the next days, and modified the balance of left-right omissions when stimuli appeared at the same time. CONCLUSION: Bilateral tDCS improved detection in both visual fields, with no privileged processing of one side, except when concurrent stimuli were presented. The results provide partial support to the hemispheric rivalry hypothesis. SIGNIFICANCE: The technique has the potential to boost attention in neglect patients but should be used as an adjuvant rather than as an alternative to functional rehabilitation.