Effects of left-sided movements on line bisection in unilateral neglect

Dual-Task Performance Involving Hand Dexterity and Cognitive Tasks and Daily Functioning in People With Schizophrenia: A Pilot Study

OBJECTIVE. This study investigated separate and concurrent performance on cognitive and hand dexterity tasks and the relationship to daily functioning in 16 people with schizophrenia and 16 healthy control participants.

METHOD. Participants performed the Purdue Pegboard Test and the Serial Seven Subtraction Test under single- and dual-task conditions and completed two daily functioning evaluations.

RESULTS. The hand dexterity of all participants declined in the dual-task condition, but the discrepancy between single-task and dual-task hand dexterity was greater in the schizophrenia group than in the control group (p < .03, d > .70, for all). The extent of discrepancy in hand dexterity was negatively correlated with daily functioning in the schizophrenia group (rs = −.3 to −.5, ps = .04–.26).

CONCLUSION. Ability to perform dual tasks may be an indicator of daily functioning in people with schizophrenia. Use of dual-task training may be considered as a therapeutic activity with these clients.

Effect of limb movements on orienting of attention in right-hemisphere stroke

A deficit disengaging attention from the ipsilesional space in order to re-orient toward the contralesional space has been reported after right-hemisphere stroke (disengage deficit) and has been related to the severity of visuospatial neglect. Neglect rehabilitation studies have shown that left limb movements improve leftward orienting; the effect, however, is variable, and the mechanism of improvement is uncertain. Thus, this study examined whether limb movements specifically reduce the underlying disengage deficit of attention after right-hemisphere stroke. The effects of active and passive limb movements (vs. no limb movement) on orienting were examined using a covert exogenously cued orienting task in groups of right-hemisphere stroke patients with and without a significant disengage deficit (DD+, DD-) and healthy older adults. As previously seen, disengage deficit scores of stroke patients were positively correlated with the severity of neglect. The leftward disengage deficit was not affected by either active or passive limb movements, however, although movements did have both alerting and distracting effects on other aspects of orienting. Thus, our results suggest that the benefits of limb movements may not be related to changes in the underlying disengage deficit, but may impact other processes that underlie left-sided orienting (e.g., arousal and voluntary strategies).

Performing lateralized approach and avoidance behaviors: effects on perceptual, affective and confidence judgments

In recent work, we showed that the judgment of affective stimuli is influenced by the degree of congruence between apparently innate hemispheric dispositions (left hemisphere positive and approach, right hemisphere negative and avoidance), and the type of movement produced by the contralateral arm (flexion-approach; extension-avoidance). Incongruent movements (e.g., right arm extension) were associated with attenuation of affective valuations. In the present study, we replicated these results. We also assessed confidence in judgments as a function of stimulus valence and congruence and determined that confidence is maximal with congruent movements and highly positive or negative stimuli, suggesting that congruence effects on affective valuation could be mediated by confidence effects. However, in a second experiment, involving judgments regarding segmented lines, congruence effects were observed only for bisected lines, for which confidence was lowest. Thus, confidence does not provide a unifying explanation for congruence effects in the performance of these two tasks.

A case study of new assessment and training of unilateral spatial neglect in stroke patients: effect of visual image transformation and visual stimulation by using a Head Mounted Display system (HMD)

Background

Unilateral spatial neglect (USN) is most damaging to an older stroke patient who also has a lower performance in their activities of daily living or those elderly who are still working. The purpose of this study was to understand more accurately pathology of USN using a new HMD system.

Methods

Two stroke patients (Subject A and B) participated in this study after gaining their informed consent and they all had Left USN as determined by clinical tests. Assessments of USN were performed by using the common clinical test (the line cancellation test) and six special tests by using HMD system in the object-centered coordinates (OC) condition and the egocentric coordinates (EC) condition. OC condition focused the test sheet only by a CCD. EC condition was that CCD can always follow the subject's movement. Moreover, the study focused on the effect of the reduced image condition of real image and the arrows.

Results

In Patient A who performed the common test and special tests of OC and EC conditions, the results showed that for the line cancellation test under the common condition, both of the percentage of the correct answers at the right and left sides in the test sheet was 100 percent. However, in the OC condition, the percentage of the correct answers at the left side in the test sheet was 44 percent and the right side was 94 percent. In the EC condition, the left side was 61 percent and the right side was 67 percent. In Patient B, according to the result of the use of reduced image condition and the arrows condition by HMD system, these line cancellation scores more increased than the score of the common test.

Conclusions

The results showed that the assessment of USN using an HMD system may clarify the left neglect area which cannot be easily observed in the clinical evaluation for USN. HMD may be able to produce an artificially versatile environment as compared to the common clinical evaluation and treatment.

Effects of object use on reaching and postural balance: a comparison of patients with unilateral stroke and healthy controls

OBJECTIVE

To evaluate whether the functional use of certain task objects while standing influences reaching performance and postural balance in persons with left or right cerebral vascular accidents, and also in healthy individuals.

DESIGN

Thirty-five stroke patients (20 patients with left and 15 patients with right cerebral vascular accidents) and 31 healthy controls (15 using the left and 16 the right arm) performed two experimental reaching tasks (task object present vs. absent) using the less affected arm while standing. For the object-present task, subjects held a glass and moved it forward as far as possible. For the object-absent task, subjects simply reached forward as far as possible. We measured reaching performance using kinematic analysis and assessed postural control using derivatives of the center of pressure, including forward displacement, mediolateral shift, and average velocity.

RESULTS

Object presence did not significantly improve overall reaching performance in any group. However, for patients with left cerebral vascular accidents and controls (using either the left or the right arm), there were significant effects of object presence on the average velocity of the center of pressure. For patients with right cerebral vascular accidents, there were significant effects of task object on the forward distance and average velocity of the center of pressure.

CONCLUSIONS

The positive findings regarding center-of-pressure derivatives suggest that a functional use of objects during a standing reaching task can decrease postural sway, as represented by the average velocity of the center of pressure, in individuals with and without stroke. Patients with right cerebral vascular accidents may benefit considerably more from functional object use during a standing reaching task, apparently because such tasks can facilitate greater forward displacement of the center of pressure.

Understanding the effects of moving visual stimuli on unilateral neglect following stroke

Moving visual stimuli have been shown to reduce unilateral neglect (ULN), however, the mechanisms underlying these effects remain poorly understood. This study compared lateralised and non-lateralised moving visual stimuli to investigate whether the spatial characteristics or general alerting properties of moving visual stimuli are responsible for reducing neglect. Post-stroke left neglect patients as well as healthy and patient control subjects were tested on a computerised line bisection task under six visual stimulus conditions. The key finding was that, relative to the no stimulus condition, leftward moving and left-sided moving visual stimuli shifted neglect patients' bisection errors leftward while the non-lateralised random moving visual stimuli did not reduce neglect patients' rightward bisection errors. The results provide evidence that spatial characteristics rather than general alerting properties of moving visual stimuli reduce rightward bisection errors in ULN. Moreover, the pattern of findings strongly supports the notion that moving visual stimuli reduce neglect by capturing attention and drawing it to a spatial location rather than by activating the attentional system via superior collicular neurons.

EFNS guidelines on cognitive rehabilitation: report of an EFNS task force

Disorders of language, spatial perception, attention, memory, calculation and praxis are a frequent consequence of acquired brain damage [in particular, stroke and traumatic brain injury (TBI)] and a major determinant of disability. The rehabilitation of aphasia and, more recently, of other cognitive disorders is an important area of neurological rehabilitation. We report here a review of the available evidence about effectiveness of cognitive rehabilitation. Given the limited number and generally low quality of randomized clinical trials (RCTs) in this area of therapeutic intervention, the Task Force considered, besides the available Cochrane reviews, evidence of lower classes which was critically analysed until a consensus was reached. In particular, we considered evidence from small group or single cases studies including an appropriate statistical evaluation of effect sizes. The general conclusion is that there is evidence to award a grade A, B or C recommendation to some forms of cognitive rehabilitation in patients with neuropsychological deficits in the post-acute stage after a focal brain lesion (stroke, TBI). These include aphasia therapy, rehabilitation of unilateral spatial neglect (ULN), attentional training in the post-acute stage after TBI, the use of electronic memory aids in memory disorders, and the treatment of apraxia with compensatory strategies. There is clearly a need for adequately designed studies in this area, which should take into account specific problems such as patient heterogeneity and treatment standardization.

EFNS guidelines on cognitive rehabilitation: report of an EFNS task force

In 1999, a Task Force was set up under the auspices of the European Federation of Neurological Societies with the aim to evaluate the existing evidence for the clinical effectiveness of cognitive rehabilitation. This review led to the development of a set of guidelines to be used in the management of adult patients with cognitive disorders due to acquired focal neurological damage.

Probability cuing of target location facilitates visual search implicitly in normal participants and patients with hemispatial neglect

We explored how variability in the probability of target locations affects visual search in normal individuals and in patients with hemispatial neglect, a deficit in attending to the contralesional side of space. Young and elderly normal participants responded faster when targets appeared in the more probable region than when targets appeared in the less probable region. Similarly, patients were sensitive to the distribution of targets, even in the neglected field. Although the attentional gradient that characterizes neglect was not eliminated, the response facilitation due to the probability distribution was proportionate to that of control participants and equal in magnitude across the neglected field. All participants exploited the uneven distribution of targets to enhance task performance without explicit instructions to do so or awareness of biases in their behavior. These results suggest that attentional orientation and sensitivity to external probabilities are possibly dissociable. An early sensory and a late motor mechanism are postulated as possibly being involved in the observed probability-matching behavior of participants.

Effektivität experimenteller und rehabilitativer Interventionen bei visuellem Neglect - Eine Metaanalyse

Zusammenfassung: Präsentiert wird eine Metaanalyse zur Wirksamkeit neuropsychologischer Interventionen bei visuellem Hemineglect. Es wurden die publizierten Outcome-Ergebnisse Experimental- und Rehabilitationsstudien zur Modifikation und Modulation des Neglectsyndroms quantitativ integriert. 133 identifizierte Studien wurden in sechs Klassen eingeteilt. Studien-, Interventions- und Patientenmerkmale dienten zur Bestimmung moderierender Einflüsse, über Sensitivitätsanalysen wurde die Robustheit der Ergebnisse abgeschätzt. Die mittlere Gesamteffektivität der Interventionen liegt um 0.8 Standardeinheiten Symptomverbesserung gegenüber dem Prä-Niveau bei Patienten mit chronischem Neglect. Spontanremissionseffekte sind aufgrund der durchschnittlichen Erkrankungsdauer als gering zu veranschlagen und konnten empirisch nicht nachgewiesen werden. Explorationstrainings, personale Intervention und Hinweisreiz-Verfahren stellen sich als überdurchschnittlich effektiv und signifikant effektiver als bloße Reduktion der Umweltanforderungen heraus.

A kinematic study of contextual effects on reaching performance in persons with and without stroke: influences of object availability

OBJECTIVE

To examine the effects of context on reaching performance in neurologically impaired and intact populations. Context was varied by the presence or absence of objects used to complete a task.

DESIGN

A counterbalanced repeated-measures design.

SETTING

A motor control laboratory in a university setting.

PARTICIPANTS

Fourteen persons with stroke and 25 neurologically intact adults.

INTERVENTIONS

Each participant was tested under two conditions: the presence of the object, in which the participant reached forward with the impaired arm (or corresponding arm) to scoop coins off the table into the other hand; and the absence of the object, in which the participant reached forward to the place where the coins would be placed in the condition of object present.

MAIN OUTCOME MEASURES

Kinematic Variables of movement time, total displacement, peak velocity, percentage of reach where peak velocity occurs, and movement units (derived from acceleration data) for reaching tasks.

RESULTS

The condition of using real objects elicited kinematically better performance of reaching movements than the condition of performing movements without relevant objects present. Better performance was reflected by shorter movement time, less total displacement, higher peak velocity, greater percentage of reach where peak velocity occurs, and fewer movement units.

CONCLUSION

The results of this study showed that the condition of object present elicited better performance of movements represented by kinematic variables than the condition of object absent. The clinical implication is that the use of real and functional objects might be an effective way of facilitating efficient, smooth, and coordinated movement with the impaired arm in persons with stroke. This study, however, should be replicated and extended to confirm the validity of its findings and to allow for generalization in various functional activities.

Preserved insight in an artist with extrapersonal spatial neglect

Several reports of cases of experienced artists showing neglect after a brain lesion can be gleaned from the literature. The analysis of their drawings might provide better insight into the symptoms of neglect than that of non-artists's production. However, most of these reports are anedoctal. We describe in some detail the case of neglect of a distinguished artist, the internationally known Federico Fellini (FF), whom we followed-up for two months after his right parietal stroke. The neuropsychological profile of his neglect syndrome was characterized by left visuo-motor neglect which persisted for two months. At onset, FF also showed indications of neglect dyslexia as well as some evidence of implicit processing of the neglected parts of visual stimuli. However, there was no sign of personal and representational neglect, and FF was well aware of his motor and attentional deficits. FF's neglect was characterised by several dissociations, of which the lack of functional carryover despite intact conceptual and semantic insight is the most relevant.