Linguistic structure modulates attention in reading: Evidence from negative concord in Italian

We report the reading performance of an Italian speaker with egocentric Neglect Dyslexia on sentences with Negative Concord structures, which contain a linguistic cue to the presence of a preceding negative marker and compare it to sentences with no such cue. As predicted, the frequency of reading the whole sentence, including the initial negative marker non, was higher in Negative Concord structures than in sentences which also started with non, but crucially, lacked the medially positioned linguistic cue to the presence of non. These data support the claim that the presence of linguistic cues to sentence structure modulates attention during reading in Neglect Dyslexia.

A Complex Intervention Integrating Prism Adaptation and Neck Vibration for Unilateral Neglect in Patients of Chronic Stroke: A Randomised Controlled Trial

Unilateral neglect in patients of chronic stroke reduces the quality of life and interferes with activities of daily living (ADL). This study aimed to investigate the effects of a complex rehabilitative programme that integrates prism adaptation (PA) and neck vibration (NV) for unilateral neglect in patients of chronic stroke. Thirty-six patients were randomised among the PA + NV group (Group A, n = 12), the NV-only group (Group B, n = 12), and the PA-only group (Group C, n = 12). The intervention was performed for 50 min/day, with five sessions per week, for 4 weeks. Albert's test and the Catherine Bergego Scale were used to measure the effects of each intervention on unilateral neglect, whereas the modified Barthel Index was used to assess the effect on ADL. All three groups exhibited a reduction in unilateral neglect and an improvement in activities of daily living after the intervention (p < 0.05). Notably, Group A (PA + NV) exhibited a significantly greater level of reduction in unilateral neglect than the other groups (p < 0.05); however, the improvement in ADL did not significantly vary across the three groups (p > 0.05). This novel complex intervention comprising PA + NV is recommended for the rehabilitation, in the clinical setting, of patients of chronic stroke with unilateral neglect.

The Puzzles Test and the Red Shapes Test as new diagnostic tools for neglect syndrome

Introduction

Neuropsychological methods for diagnosing neglect syndrome (NS) are focused on identifying the inability of patients to respond to stimuli localized in contralesional space. There are a large number of methods capable of diagnosing spatial neglect, but at the same time having various limitations and restrictions in their use.

Objectives

To devise and to test universal diagnostic techniques for visuospatial neglect detection.

Methods

1) A.R. Luria test battery; Trail Making Test (Part A); the Bells Test; 2) Authors’ methods: the Puzzles Test, the Red Shapes Test. A total of 47 patients after stroke with right hemisphere damage participated in the study and were divided into a target (18 patients with NS) and a control (29 patients without NS) groups. The Puzzles Test consists of three tasks: turning over cards, completing a sentence using cards with letters, completing a picture. The Red Shapes Test consisted in the search for a variable number of geometric shapes. Objective indicators of the study: total task completion time, the number of left omissions.

Results

The sensitivity of the tests to NS was examined using the Mann-Whitney U-test. Differences in the number of omissions and task completion time between patients with and without spatial neglect were statistically significant regarding all tasks: turning over cards (p=0.01), completing a sentence (p<0.001), completing a picture (p<0.001), finding geometric shapes (p<0.01).

Conclusions

The Puzzles Test and Red Shapes Test along with the foreign tests (the Bells Test, Trail Making Test) are sufficiently effective methods for spatial neglect detection.

Disclosure

No significant relationships.

Visuomotor misalignment induced through immersive virtual reality to improve spatial neglect: a case-series study

One evidence-based treatment for spatial neglect is prism adaptation (PA) treatment. PA after-effects, i.e., the implicit shifts in the arm reaching position toward the neglected side of space after prism removal, are considered fundamental to PA treatment effects. In the present study, the arm reaching position was shifted through a visuomotor misalignment procedure using immersive virtual reality (VR). To examine whether this procedure might have a beneficial impact on spatial neglect, we conducted a multi-baseline experiment in three individuals with chronic left-sided neglect post stroke. Improved spatial neglect was observed in all participants immediately after 5 sessions with two rounds in each. Two participants demonstrated lasting or continuous improvement two weeks later. Participants' pattern of brain lesions did not appear to clearly explain performance differences. The findings suggest that VR-induced visuomotor misalignment may improve spatial neglect immediately after a multi-session treatment course. The optimal number of sessions will be determined by future studies with a larger sample size, which may also elucidate the number of sessions sufficient for sustained improvement in most patients. Further investigations will identify the neural mechanisms underlying VR-induced visuomotor misalignment, which may or may not be identical to PA after-effects.

The mobility assessment course: A ready-to-use dynamic measure of visuospatial neglect

The Mobility Assessment Course (MAC) is a tool to measure visuospatial neglect in a dynamic fashion. Although the MAC has been shown to dissociate between patients with and without neglect, it remains unclear whether it is applicable in clinical settings. We evaluated the MAC regarding its (1) feasibility as a diagnostic tool as part of standard care, (2) construct validity, and (3) underlying constructs and potential confounders. A consecutive sample of stroke patients admitted to inpatient rehabilitation completed the MAC, shape cancellation, line bisection, and/or Catherine Bergego Scale (CBS) as part of the standard assessment. To assess feasibility, we computed the percentage of patients who completed the MAC. Construct validity was tested by evaluating MAC performance between patients with and without neglect and controls. Finally, a regression analysis was conducted to assess underlying constructs and potential confounders of MAC performance (i.e., level of mobility and lesion side). The MAC was completed by 82% of patients (N = 182/223; of whom 145 completed all tasks). Patients with neglect performed worse on the MAC (indicating more severe neglect) compared to patients without neglect and controls. The MAC had a lower sensitivity and higher specificity than paper-and-pencil tasks and the CBS. Performance on shape cancellation, line bisection, and CBS were predictors of MAC performance. Level of mobility and lesion side did not predict MAC scores, indicating that these factors do not confound its reliability. To conclude, the MAC is an easy-to-implement tool to evaluate neglect in a dynamic manner, which can be administered in addition to conventional paper-and-pencil tasks.

Comparing the effectiveness of bimanual and unimanual mirror therapy in unilateral neglect after stroke: A pilot study

BACKGROUND

Unilateral neglect in stroke patients is a major obstacle to rehabilitation, which is a great challenge for therapists.

OBJECTIVE

This study aimed to compare the effectiveness of bimanual mirror therapy (BMT) and unimanual mirror therapy (UMT), the two protocols of mirror therapy, for the reduction of the symptoms of unilateral neglect in stroke patients.

METHODS

Twenty-eight individuals were randomly assigned to the UMT or BMT groups. Both groups received mirror therapy for 30 minutes per day, 5 days a week, for a period of 4 weeks. The Star Cancelation Test (SCT), Line Bisection Test (LBT), Picture Scanning test (PST), and Korean Catherine Bergego Scale (K-CBS) were used to measure the change in unilateral neglect, and the Korean version of the Modified Barthel Index (K-MBI) was used to evaluate activities of daily living (ADL).

RESULTS

The results of SCT, LBT, PST, and K-CBS showed significant decreases in unilateral neglect in both groups (p <  0.05). K-MBI improved significantly in both groups (p <  0.05). There were significant differences between the two groups in the unilateral neglect tests (p <  0.05), but no significant difference in ADL evaluation (p >  0.05).

CONCLUSIONS

Mirror therapy protocols can be applied to treat unilateral neglect in stroke patients. However, BMT may be more beneficial for reducing the symptoms of unilateral neglect.

Theta-burst transcranial magnetic stimulation for the treatment of unilateral neglect in stroke patients: A systematic review and best evidence synthesis

BACKGROUND

Unilateral neglect (UN) is a common and disabling disorder after stroke. UN is a strong and negative predictor of functional rehabilitative outcome. Non-invasive brain stimulation, such as theta-burst transcranial magnetic stimulation (TBS), is a promising rehabilitation technique for treating stroke-induced UN.

OBJECTIVE

To systematically review the available literature, researching whether TBS of the contra-lesional hemisphere is more effective than standard rehabilitation in improving symptoms of UN in patients with right hemisphere stroke.

REVIEW METHODS

A systematic review was conducted to retrieve randomized controlled trials (RCTs) that were relevant to the objective of this review. PubMed, Ovid and Cochrane Library electronic databases were comprehensively searched from inception up to February 2021. Of the included studies, methodological quality was assessed using the PEDro scale, whereafter a best evidence synthesis (BES) was conducted to summarize the results.

RESULTS

Nine RCTs investigating the effects of TBS on stroke-induced UN symptoms were included in this review. Seven studies assessing continuous TBS (cTBS) found significantly greater amelioration of UN symptoms in the TBS intervention group when compared to the control group; one study assessing cTBS found no such significant difference. One study assessing intermittent TBS (iTBS) found significant between-group differences in favor of the intervention. The BES yielded strong evidence in favor of cTBS, and limited evidence in favor of iTBS.

CONCLUSIONS

The included studies in the present review allow the conclusion that TBS can have favorable effects on UN recovery in stroke patients. Its clinical use is recommended in conjunction with cognitive rehabilitation and occupational or physical rehabilitation as needed. However, many aspects for optimal usage of TBS therapy in clinical settings, such as exact TBS protocols, number of sessions, and treatment duration, are not clear.

Mirror therapy for unilateral neglect after stroke: A systematic review

BACKGROUND AND PURPOSE

The effect of mirror therapy for unilateral neglect after stroke currently remains uncertain.

METHODS

This systematic review investigated the effect of mirror therapy on neglect and daily living activities in patients with unilateral neglect after stroke when compared with no treatment, sham mirror therapy, or routinely applied therapies only. We performed a systematic electronic search of PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang Data to identify relevant randomized control trials (RCTs).

RESULTS

We included five RCTs in the data synthesis. Mirror therapy (combined or not with other treatments) was more effective in improving neglect as compared with sham mirror therapy or no treatment (combined or not with the other therapies; standard mean difference [SMD] = 1.62, 95% confidence interval [CI] = 1.03-2.21, p < 0.00001). Mirror therapy (combined or not with other therapies) was effective in improving daily living activities as compared with sham mirror therapy or no treatment (combined or not with the other therapies; SMD = 2.09, 95% CI = 0.63-3.56, p = 0.005).

CONCLUSIONS

Our results show that mirror therapy effectively improves neglect and daily living activities in patients with unilateral neglect after stroke. Future trials with high methodological quality and larger sample sizes are needed to determine the immediate and long-term effect of appropriate mirror therapy protocol for unilateral neglect.

Independence in Daily Activities after Stroke among Occupational Therapy Patients and Its Relationship with Unilateral Neglect

More research is needed to better understand the impact of occupational therapy (OT) in stroke patients and syndromes of unilateral neglect (UN) and anosognosia. A prospective, observational, longitudinal design was conducted on a sample of 27 OT patients. The objectives were to examine: (1) the presence of UN and anosognosia; (2) the functional outcomes; and (3) the association of UN at baseline with functional status at discharge from OT. The outcomes were Barthel (functional independence) and the Rivermead Mobility Index (RMI). The baseline proportion of participants with UN was 33% according to the Star Cancellation Test (STC), and 48.1% according to the Catherine Bergego Scale (CBS) therapist-version. There was a significant difference between the therapist and participant-rated CBS scores (p = 0.004). Functional independence improved significantly between the initial and final assessments (p < 0.001); the effect size (r) was large (r = 0.61). There was a significant improvement in RMI scores (p < 0.001), which was large in size (r = 0.59). Both the STC and CBS-therapist scores were significantly correlated with the Barthel (p < 0.001, p = 0.005, respectively) and with the RMI (p = 0.004, p = 0.028, respectively). The participants substantially enhanced their functional status skills. UN and anosognosia were common problems, and neglect was associated with worse OT program outcomes.

How does the number of targets affect visual search performance in visuospatial neglect?

INTRODUCTION

Impairments in visual search are a common symptom in visuospatial neglect (VSN). The severity of the lateralized attention bias in visual search tasks can vary depending on the number of distractors: the more distractors, the more targets are missed. However, little is known about how the number of targets affect search performance in VSN. The aim of the current study was to examine the effect of the number of targets on hit rate in VSN.

METHODS

We included 23 stroke patients with right-brain damage and VSN, 55 with right-brain damage without VSN, and 49 with left-brain damage without VSN, all admitted for inpatient rehabilitation. In a visual search task, patients had to find and tap targets, presented along with non-targets. The location and number of targets varied from trial to trial, allowing the evaluation of the effects of number and location of targets on hit rate.

RESULTS

VSN patients detected a lower percentage of targets when more targets were present. For patients with right-brain damage without VSN, adding targets only reduced the hit rate of the most contralesional target. No effect of number of targets on hit rate was seen in patients with left-brain damage. Additionally, VSN patients found less contralesional targets than ipsilesional targets, made more delayed revisits, and had an initial rightward bias when compared to the other groups. There were no differences in search time, search consistency, or immediate revisits between groups. There was a moderate positive relation between the hit rate asymmetry score in our search task and conventional paper-and-pencil VSN tasks, and neglect behavior in daily life.

CONCLUSIONS

In VSN patients, a higher number of targets reduces the hit rate. The reduced hit rate in visual search evoked by additional targets should be taken into account when assessing visual search in VSN.

Proprioceptive impairment in unilateral neglect after stroke: A systematic review

Introduction:

Unilateral neglect is a debilitating condition that can occur after stroke and can affect a variety of domains and modalities, including proprioception. Proprioception is a sensorimotor process essential to motor function and is thus important to consider in unilateral neglect. To date, there has not been a comprehensive review of studies examining the various aspects of proprioceptive impairment in unilateral neglect after stroke. This review aimed to determine if people with unilateral neglect have more severe proprioceptive impairments than those without unilateral neglect after stroke.

Methods:

The MEDLINE, Embase, Scopus, CINAHL and Web of Science databases were searched from inception to September 2019 using an a priori search strategy. Two independent reviewers screened abstracts and full texts, and extracted data from the included full texts. A third reviewer resolved disagreements at each step. Risk of bias was assessed using the AXIS Quality Assessment tool.

Results:

A total of 191 abstracts were identified, with 56 eligible for full-text screening. A total of 18 studies were included in the review and provided evidence that people with unilateral neglect have more severe proprioceptive impairment than people without unilateral neglect. This impairment is present in multiple subtypes of unilateral neglect and aspects of proprioception. Most studies had a moderate risk of bias.

Conclusion:

People with unilateral neglect after stroke are more likely to have impaired processing of multiple types of proprioceptive information than those without unilateral neglect. However, the available evidence is limited by the large heterogeneity of assessment tools used to identify unilateral neglect and proprioception. Unilateral neglect and proprioception were rarely assessed comprehensively.

PROSPERO Registration: CRD42018086070.

Mirror Therapy in Stroke Rehabilitation: Current Perspectives

In contrast to varied therapy approaches, mirror therapy (MT) can be used even in completely plegic stroke survivors, as it uses visual stimuli for producing a desired response in the affected limb. MT has been studied to have effects not just on motor impairments but also on sensations, visuospatial neglect, and pain after stroke. This paper attempts to systematically review and present the current perspectives on mirror therapy and its application in stroke rehabilitation, and dosage, feasibility and acceptability in stroke rehabilitation. An electronic database search across Google, PubMed, Web of Science, etc., generated 3871 results. After screening them based on the inclusion and exclusion criteria, we included 28 studies in this review. The data collected were divided on the basis of application in stroke rehabilitation, modes of intervention delivery, and types of control and outcome assessment. We found that most studies intervened for upper limb motor impairments post stroke. Studies were equally distributed between intervention in chronic and acute phases post stroke with therapy durations lasting between 1 and 8 weeks. MT showed definitive motor and sensory improvements although the extent of improvements in sensory impairments and hemineglect is limited. MT proves to be an effective and feasible approach to rehabilitate post-stroke survivors in the acute, sub-acute, and chronic phases of stroke, although its long-term effects and impact on activities of daily living need to be analysed extensively.

Is congruent movement training more effective than standard visual scanning therapy to ameliorate symptoms of visuospatial neglect? Study protocol of a randomised control trial

INTRODUCTION

Approximately 30% of all patients with stroke show visuospatial neglect (VSN). Currently, visual scanning therapy (VST) is applied in clinical settings to attenuate neglect symptoms. VST builds on the premise that eye movements to the affected hemifield lead to a concurrent shift of visual attention. Congruent movements with different effectors of the motor system, for example, eye and hand, can produce an even larger boost of attention compared with a single effector. This congruency principle may produce a powerful bias in the motor system, which may counteract the pathological biases in the attentional system of neglect patients. Therefore, an intervention with congruent eye and hand movements may result in greater attenuation of neglect compared with an intervention with single eye movements as applied in standard VST. The current randomised controlled trial will investigate the beneficial effects of this updated version of VST by comparing changes in performance on standard neuropsychological neglect tasks and severity of neglect in activities of daily living.

METHODS AND ANALYSIS

Thirty VSN patients in the subacute phase poststroke onset will be randomly assigned to one of two groups: congruent eye and hand movement training (experimental group) versus standard VST (control group). Each patient will receive 10 sessions of training, 30 min each, within 2 weeks. Performance on standard neuropsychological neglect tasks, a visual discrimination task, severity of neglect in ADL and eye movement characteristics before and after intervention will be compared for and between both groups.

ETHICS AND DISSEMINATION

This study has been approved by the ethical committee of the University Medical Centre Utrecht. All subjects will participate voluntarily and will give written informed consent. Results of this study will be published in peer-reviewed scientific journals and presented at international conferences.

TRIAL REGISTRATION NUMBER

NTR7005.

Assessment of unilateral neglect in stroke: Simplification and structuring of test items

Statement of context

Unilateral neglect is a complex impairment that is common after stroke and limits occupational performance. Sensitive assessment of unilateral neglect is critical for planning treatment and ensuring safe community discharge.

Critical reflection on practice

This reflection describes unexpected findings in the assessment of neglect with two individuals in the acute phase of recovery post stroke. When trialing a new activity based test battery, we observed few neglect behaviors during test tasks despite observation of multiple neglect behaviors outside of the testing situation. Upon reflection, we better understood how simplification and structuring of test items and environments could impact the observation and assessment of neglect behaviors.

Implications for practice

This practice analysis further supports the use of multiple assessments when evaluating unilateral neglect and specifically encourages the inclusion of assessment methods that maintain the complexity of everyday tasks and environments.

Value and Efficacy of Transcranial Direct Current Stimulation in the Cognitive Rehabilitation: A Critical Review Since 2000

Non-invasive brain stimulation techniques, including transcranial direct current stimulation (t-DCS) have been used in the rehabilitation of cognitive function in a spectrum of neurological disorders. The present review outlines methodological communalities and differences of t-DCS procedures in neurocognitive rehabilitation. We consider the efficacy of tDCS for the management of specific cognitive deficits in four main neurological disorders by providing a critical analysis of recent studies that have used t-DCS to improve cognition in patients with Parkinson's Disease, Alzheimer's Disease, Hemi-spatial Neglect, and Aphasia. The evidence from this innovative approach to cognitive rehabilitation suggests that tDCS can influence cognition. However, the results show a high variability between studies both in terms of the methodological approach adopted and the cognitive functions targeted. The review also focuses both on methodological issues such as technical aspects of the stimulation (electrode position and dimension; current intensity; duration of protocol) and on the inclusion of appropriate assessment tools for cognition. A further aspect considered is the optimal timing for administration of tDCS: before, during or after cognitive rehabilitation. We conclude that more studies using common methodology are needed to gain a better understanding of the efficacy of tDCS as a new tool for rehabilitation of cognitive disorders in a range of neurological disorders.

The effects of repetitive transcranial magnetic stimulation on unilateral neglect of acute stroke patients: A randomised controlled trial

Background

Rehabilitation of the unilateral neglect of acute stroke patients represents a major challenge.

Objectives

This study aimed to evaluate the effects of repetitive transcranial magnetic stimulation on the functional recovery of stroke patients with unilateral neglect.

Methods

Twenty patients with stroke were randomly assigned to two groups: a repetitive transcranial magnetic stimulation group (experimental) and a control group. The stroke patients in the experimental group underwent repetitive transcranial magnetic stimulation therapy and comprehensive rehabilitation therapy. The stroke patients in the control group underwent sham magnetic stimulation therapy and comprehensive rehabilitation therapy. The patients in both groups received therapy 5 days per week for 4 weeks. The Motor Free Visual Perception Test (MVPT), Line Bisection Test (LBT), Albert Test (AT), and Star Cancellation Test (SCT) were assessed before and after the 4-week therapy period.

Results

The experimental group showed a significant increase in the MVPT, LBT, AT, and SCT values compared with the preintervention values (p < 0.05). Furthermore, the control group showed a significant increase in the MVPT, LBT, and AT results compared with the preintervention results (p < 0.05). A significant difference in the post-training gains for the MVPT (8.9 ± 2.5 vs. 4.8 ± 3.0), LBT (-19.3 ± 7.5 vs. -6.5 ± 9.5), AT (13.1 ± 8.0 vs. 4.0 ± 1.9), and SCT (-13.6 ± 6.9 vs. -4.5 ± 6.9) were observed between the experimental group and the control group (p < 0.05). In addition, the effect size for gains in the experimental and control groups was very large in MVPT and AT (effect size = 3.25 and 2.90), respectively, and the effect size for gains in the experimental and control groups was small in LBT and SCT (effect size = 0.22 and 0.23, respectively).

Conclusion

The current study findings indicated that repetitive transcranial magnetic stimulation may be beneficial in decreasing the unilateral neglect of stroke patients.

Effects of lateralized light flash and color on unilateral neglect

PURPOSE

Bottom-up-based sensory stimulation has been useful in promoting recovery from post-stroke neglect. Light and color are salient stimuli for guiding our orienting behaviors and influence the degree of spatial bias. This study evaluated the effects of lateralized light flash and color on spatial bias in unilateral neglect (UN).

METHOD

We enrolled 15 individuals with UN as a consequence of a right hemispheric stroke of less than 65 d. This was a 3 × 3 design study with three conditions of lens color (colorless, red, and blue) and three conditions of flash light locations (no flash, left, and right).

RESULTS

All participants showed a decrease in ipsilesional spatial bias under left-side light flash and a red lens. Right-side light flash and a blue lens induced more rightward bias than other conditions.

CONCLUSIONS

This evidence confirms the use of sensory stimulation to complement post-stroke UN remediation. Lateralized light flash to the contralesional space and red-colored lenses have beneficial effects on amelioration of UN, whereas ipsilesional light flash and the color blue may exacerbate ipsilesional spatial bias in stroke survivors with UN. Implications for Rehabilitation Contralesional light flash and the color red may ameliorate ipsilesional spatial bias in stroke survivors with unilateral neglect (UN). Ipsilesional flash of light and the color blue may worsen ipsilesional spatial bias in stroke survivors with UN.

[Nursing care of unilateral neglect patients]

The prevalence of unilateral neglect among stroke patients has risen to 82% and 69%, respectively, in acute wards and rehabilitation units. Neglect may restrict the activities of patients and reduce their quality of life. Patients are often unaware of their neglect behavior and of their inability to see or feel persons or objects on their affected side. Healthcare providers should pay greater attention to the signs of neglect behavior in patients. Neglect is a silent syndrome for both patients and healthcare providers. This article reviews the definition of unilateral neglect as well as its associated characteristics, theoretical interpretations, rehabilitation, and nursing care. The authors hope that the contents of this article may help healthcare professionals assess and provide care to patients with neglect problems in order to decrease the negative impacts of neglect on patients and improve their daily functions.

The effectiveness of different treatment modalities for the rehabilitation of unilateral neglect in stroke patients: a systematic review

BACKGROUND

Patients suffering from unilateral neglect syndrome (UNS) are not able to respond to stimuli administered to the side of the body opposite to the lesion. UNS is most commonly seen after right-hemisphere lesions. Patients with UNS experience more problems with activities of daily living and recovery after stroke is delayed.

OBJECTIVE

To investigate which treatment modalities can alleviate the symptoms of UNS after stroke and to determine their effectiveness.

METHODS

Databases PubMed, Web of knowledge and PEDro have been searched. Quality assessment was conducted using the 9-item Delphi list. Data extraction was performed by the first author. Effect sizes have been calculated using Cohen's d.

RESULTS

15 RCT's have been included. Most studies used add-on therapies. Almost all studies found improvements in both groups, but only 7 trials showed statistically significant between group differences in favor of the experimental group. Large effect sizes were found in only four studies.

CONCLUSIONS

All the interventions discussed in this review can reduce the symptoms of UNS. However, TENS, optokinetic stimulation, somatosensory electrostimulation, mirror therapy and virtual reality training seem to be the most effective treatment methods (d > 0,80). Future research should focus on producing studies of higher methodological quality with larger sample sizes.

Tonal cues modulate line bisection performance: preliminary evidence for a new rehabilitation prospect?

The effect of the presentation of two different auditory pitches (high and low) on manual line-bisection performance was studied to investigate the relationship between space and magnitude representations underlying motor acts. Participants were asked to mark the midpoint of a given line with a pen while they were listening a pitch via headphones. In healthy participants, the effect of the presentation order (blocked or alternative way) of auditory stimuli was tested (Experiment 1). The results showed no biasing effect of pitch in blocked-order presentation, whereas the alternative presentation modulated the line-bisection. Lower pitch produced leftward or downward bisection biases whereas higher pitch produced rightward or upward biases, suggesting that visuomotor processing can be spatially modulated by irrelevant auditory cues. In Experiment 2, the effect of such alternative stimulations in line bisection in right brain damaged patients with a unilateral neglect and without a neglect was tested. Similar biasing effects caused by auditory cues were observed although the white noise presentation also affected the patient's performance. Additionally, the effect of pitch difference was larger for the neglect patient than for the no-neglect patient as well as for healthy participants. The neglect patient's bisection performance gradually improved during the experiment and was maintained even after 1 week. It is therefore, concluded that auditory cues, characterized by both the pitch difference and the dynamic alternation, influence spatial representations. The larger biasing effect seen in the neglect patient compared to the no-neglect patient and healthy participants suggests that auditory cues could modulate the direction of the attentional bias that is characteristic of neglect patients. Thus, the alternative presentation of auditory cues could be used as rehabilitation for neglect patients. The space-pitch associations are discussed in terms of a generalized magnitude system.

Non-invasive brain stimulation in neglect rehabilitation: an update

Here, we review the effects of non-invasive brain stimulation such as transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) in the rehabilitation of neglect. We found 12 studies including 172 patients (10 TMS studies and 2 tDCS studies) fulfilling our search criteria. Activity of daily living measures such as the Barthel Index or, more specifically for neglect, the Catherine Bergego Scale were the outcome measure in three studies. Five studies were randomized controlled trials with a follow-up time after intervention of up to 6 weeks. One TMS study fulfilled criteria for Class I and one for Class III evidence. The studies are heterogeneous concerning their methodology, outcome measures, and stimulation parameters making firm comparisons and conclusions difficult. Overall, there are however promising results for theta-burst stimulation, suggesting that TMS is a powerful add-on therapy in the rehabilitation of neglect patients.

Rehabilitation Interventions for Unilateral Neglect after Stroke: A Systematic Review from 1997 through 2012

A systematic review of the effectiveness of rehabilitation for persons with unilateral neglect (UN) after stroke was conducted by searching the computerized databases from 1997 through 2012. Randomized controlled trials (RCTs) of neglect treatment strategies for stroke patients which used the Behavioral Inattention Test (BIT) as the primary outcome measure were eligible for inclusion. Out of 201 studies initially identified, 12 RCTs covering 277 participants were selected for analysis. All had the same weakness of low power with smaller samples and limitation in the blinding of the design. Prism Adaptation (PA) was the most commonly used intervention while continuous Theta-burst stimulation (cTBS) appeared to be a new approach. Meta-analysis showed that for immediate effects, the BIT conventional subscore had a significant and large mean effect size (ES = 0.76; 95% CI 0.28-1.23; p = 0.002) whereas the BIT total score showed a modestly significant mean ES (ES = 0.55; 95% CI 0.16-0.94; p = 0.006). No significant mean ES in sensitivity analysis was found for long-lasting effects across all BIT outcomes. PA appeared to be the most effective intervention based on the results of pooled analysis. More rigorous studies should be done on repetitive transcranial magnetic stimulation (rTMS) before it can be concluded that it is a promising treatment for UN.

Extracting the mean size across the visual field in patients with mild, chronic unilateral neglect

Previous studies suggest that normal vision pools information from groups of objects in a display to extract statistical summaries (e.g., mean size). Here we explored whether patients with mild, chronic left neglect were able to extract statistical summaries on the right and left sides of space in a typical manner. We tested four patients using a visual search task and varied the mean size of a group of circles within the display. On each trial, a single circle first appeared in the center of the screen (the target). This circle varied in size from trial to trial. Then a multi-item display appeared with circles of various sizes grouped together either on the left or right side of the display. The instructions were to search the circles and determine whether the target was present or not. The circles were always accompanied by a group of task-irrelevant triangles that appeared on the opposite side of the display. On half the trials, the mean size of the circles was the size of the target. On the other half the mean size was different from the target. The patients were not told that this was the case, and no explicit report of the statistics was required. The results showed that when the targets were absent patients produced more false alarms to the mean than non-mean size when the circles were on the left (neglected) side of the display. This finding demonstrates that statistical information was implicitly extracted from the left group of circles. However, summary statistics on the right side were not limited to the circles. Rather it appears that participants pooled the distractors with the target circles, yielding a skewed statistical summary on the right side. These findings are discussed as they relate to statistical summary processing, visual search and segregation of right and left items in patients with mild, chronic unilateral neglect.

Speed impairs attending on the left: comparing attentional asymmetries for neglect patients in speeded and unspeeded cueing tasks

Visuospatial neglect after stroke is often characterized by a disengage deficit on a cued orienting task, in which individuals are disproportionately slower to respond to targets presented on the contralesional side of space following an ispilesional cue as compared to the reverse. The purpose of this study was to investigate the generality of the finding of a disengage deficit on another measure of cued attention, the temporal order judgment (TOJ) task, that does not depend upon speeded manual responses. Individuals with right hemisphere stroke with and without spatial neglect and older healthy controls (OHC) were tested with both a speeded RT cueing task and an unspeeded TOJ-with-cuing task. All stroke patients evidenced a disengage deficit on the speeded RT cueing task, although the size and direction of the bias was not associated with the severity of neglect. In contrast, few neglect patients showed a disengage deficit on the TOJ task. This discrepancy suggests that the disengage deficit may be related to task demands, rather than solely due to impaired attentional mechanisms per se. Further, the results of our study show that the disengage deficit is neither necessary nor sufficient for neglect to manifest.

Neuroanatomical Dissections of Unilateral Visual Neglect Symptoms: ALE Meta-Analysis of Lesion-Symptom Mapping

Unilateral visual neglect is commonly defined as impaired ability to attend to stimuli presented on the side of visual space contralateral to the brain lesion. However, behavioral analyses indicate that different neglect symptoms can dissociate. The neuroanatomy of the syndrome has been hotly debated. Some groups have argued that the syndrome is linked to posterior parietal cortex lesions, while others report damage within regions including the superior temporal gyrus, insula, and basal ganglia. Several recent neuroimaging studies provide evidence that heterogeneity in the behavioral symptoms of neglect can be matched by variations in the brain lesions, and that some of the discrepancies across earlier findings might have resulted from the use of different neuropsychological tests and/or varied measures within the same task for diagnosing neglect. In this paper, we review the evidence for dissociations between both the symptoms and the neural substrates of unilateral visual neglect, drawing on ALE (anatomic likelihood estimation) meta-analyses of lesion-symptom mapping studies. Specifically, we examine dissociations between neglect symptoms associated with impaired control of attention across space (in an egocentric frame of reference) and within objects (in an allocentric frame of reference). Results of ALE meta-analyses indicated that, while egocentric symptoms are associated with damage within perisylvian network (pre- and postcentral, supramarginal, and superior temporal gyri) and damage within sub-cortical structures, more posterior lesions including the angular, middle temporal, and middle occipital gyri are associated with allocentric symptoms. Furthermore, there was high concurrence in deficits associated with white matter lesions within long association (superior longitudinal, inferior fronto-occipital, and inferior longitudinal fasciculi) and projection (corona radiata and thalamic radiation) pathways, supporting a disconnection account of the syndrome. Using this evidence we argue that different forms of neglect link to both distinct and common patterns of gray and white matter lesions. The findings are discussed in terms of functional accounts of neglect and theoretical models based on computational studies of both normal and impaired attention functions.

Designing rehabilitation programs for neglect: could 2 be more than 1+1?

Unilateral neglect is a multimodal neuropsychological disorder that has puzzled scientists for a long time. Many interventions have been developed, but only a handful has proven to be effective. This review examines whether applying different therapeutic techniques in combination will increase therapeutic benefits. Studies were reviewed where therapies are applied sequentially or in combination with other techniques. The results indicate that combining different interventions leads to increased general improvement compared with other noncombined designs, even when the number of treatment sessions is not constant. Practical and theoretical aspects of different treatments are discussed. The combined approach to treatment may have direct relevance to disorders other than neglect. This report introduces a new classification scheme for different interventions with the aim of facilitating more focused therapy. Finally, suggestions are made as to what the focus of future studies of neglect therapy should be and how therapeutic benefits might be maximized.

Strength in numbers: combining neck vibration and prism adaptation produces additive therapeutic effects in unilateral neglect

Unilateral neglect is a multifaceted disorder. Many authors have, for this reason, speculated that the best treatment for neglect will involve combinations of different therapeutic techniques. Two well-known interventions, neck vibration (NV) and prism adaptation (PA), have often been considered to be among the most effective treatments for neglect. Here, two experiments were performed to explore possible additive benefits when these interventions are used in combination to treat chronic neglect. Both experimental groups received NV for 20 minutes, while the second group received simultaneous PA. The effects of treatment were measured with a time-restricted and feedback-based visual search task, which has previously been found to abolish the beneficial effects of PA, and with standard neglect tests. Baseline and intervention measures were performed on separate days. Findings for both groups indicated improved visual search following intervention, but the patients that underwent the combined intervention (NVPA) showed clear improvements on visual search paper and pencil neglect tests unlike the NV-only group. Overall, our results suggest that PA strengthens the effects of NV and that feedback-based tasks do not abolish the beneficial effects of PA, when NV is applied simultaneously. The results support the view that the most effective treatment for neglect will involve the combination of different treatments.

No disillusions in auditory extinction: perceiving a melody comprised of unperceived notes

The formation of coherent percepts requires grouping together spatio-temporally disparate sensory inputs. Two major questions arise: (1) is awareness necessary for this process; and (2) can non-conscious elements of the sensory input be grouped into a conscious percept? To address this question, we tested two patients suffering from severe left auditory extinction following right hemisphere damage. In extinction, patients are unaware of the presence of left side stimuli when they are presented simultaneously with right side stimuli. We used the ‘scale illusion’ to test whether extinguished tones on the left can be incorporated into the content of conscious awareness. In the scale illusion, healthy listeners obtain the illusion of distinct melodies, which are the result of grouping of information from both ears into illusory auditory streams. We show that the two patients were susceptible to the scale illusion while being consciously unaware of the stimuli presented on their left. This suggests that awareness is not necessary for auditory grouping and non-conscious elements can be incorporated into a conscious percept.

Bias in magnitude estimation following left hemisphere injury

There is a growing interest both in identifying the neural mechanisms of magnitude estimation and in identifying forms of bias that can explain aspects of behavioral syndromes like unilateral neglect. Magnitude estimation is associated with activation of temporo-parietal cortex in both cerebral hemispheres of normal subjects; however, it is unclear if and how left hemisphere lesions bias magnitude estimation because the infrequency of neglect and the presence of aphasia in these subjects confound examination. In contrast, we examined magnitude estimation using 12 different types of sensory stimuli that spanned five sensory domains in two patients with very different clinical presentations following unilateral left hemisphere stroke. One patient had neglect sub-acutely without aphasia. The other had aphasia chronically after a temporo-parietal lesion but not neglect. The neglect patient was re-examined 48 h after being treated with modafinil (Provigil) for decreased arousal. Both patients demonstrated bias in magnitude estimation relative to normal subjects (n=83). Alertness improved in the neglect patient after taking modafinil. His neglect also resolved and his magnitude estimates more closely resembled those of normal subjects. This is the first evidence, to our knowledge, that left hemisphere injury can bias magnitude estimation in a manner similar but not identical to that associated with right hemisphere injury.