Assessment of spatial neglect in clinical practice: A nationwide survey

This study was part of a nationwide, anonymous, open Internet survey conducted amongst healthcare professionals in Denmark on the assessment and treatment of spatial neglect (SN). The objective was to describe knowledge and practices in the assessment of SN in current clinical practice across different healthcare sectors and professions. Data included the perceived prevalence, assessment methods and observations, subtypes and differential diagnostics of SN. A total of 525 professionals participated in the survey. The vast majority (81.5%) reported that assessment of SN was provided by their workplace. The median of perceived prevalence of SN was 35% (IQR 22-51) but major differences were found between professions. Occupational therapists and psychologists appeared to be most involved in assessment, whilst nursing staff and speech therapists were least involved. Subjective observations were the most common assessment method (90%). Conversely, systematic ADL observations, paper-and-pencil tests, confrontational tests and computerized tests were less common. The survey revealed large differences in the assessment methods and awareness of various aspects of SN symptoms (subtypes and differential diagnostics) between different healthcare professions. The results emphasize the need for international multidisciplinary clinical guidelines on how to assess SN and distinguish between different subtypes and differential diagnoses.

Treatment of spatial neglect in clinical practice: A nationwide survey

OBJECTIVES

Clinical research has documented a range of evidence-based treatment approaches for spatial neglect (SN), but there is a lack of research on the implementation of treatment into clinical practice. The purpose of this study is to describe the current clinical practice of SN treatment across healthcare sectors including involved professions, methods, timing and sources of evidence.

MATERIAL AND METHODS

This is the second part of a nationwide, anonymous, open Internet survey that was conducted among healthcare professionals in Denmark on assessment and treatment of SN.

RESULTS

A total of 525 healthcare professionals participated in the survey of which 411 (78.3%) reported that SN treatment was provided at their workplace. Occupational and physiotherapist were most often involved in the treatment, most commonly characterized by training of activities of daily living (ADL), sensoric stimulation and cueing. Less frequently reported were evidence-based methods such as prism adaptation and visual scanning. The overall intensity of the SN treatment varied considerably across sectors and might consequently be inadequate. A minority of the participants consulted clinical research evidence in their choice of SN treatment approaches.

CONCLUSIONS

There is a profound lack of dissemination and translation of clinical research into current clinical practice, which unarguably leads to an underuse of evidence-based treatment approaches in SN rehabilitation. The results call for international multidisciplinary clinical guidelines for the treatment of SN at different stages of rehabilitation and the tailoring of treatment approaches to the individual patient.

A free and simple computerized screening test for visual field defects

About 30-40% of stroke patients suffer from visual field defects following injury. These can interfere with the standard neuropsychological assessment and complicate the interpretation of tests that use visual materials. However, information about the integrity of a patient's central visual field is often unavailable. We, therefore, designed a screening tool, the computerized visual field test (c-VFT), specifically targeted at providing easily available, but rough, information about patients' central visual field. c-VFT was tested in two samples of stroke patients. Eleven patients were tested on c-VFT and on the Esterman test. Five patients were tested on c-VFT and the Humphrey Visual Field Analyzer (HFA), central 10-2. Criterion validity of the c-VFT was investigated by calculating quadrantwise intraclass correlation for both comparisons. For the HFA comparison, we also calculated point-to-point intraclass correlation, sensitivity, and specificity. Analyses revealed moderately good correspondence between c-VFT and the Esterman test, and between c-VFT and HFA 10-2, respectively. When looking specifically at test points within one degree of visual angle apart in the two tests, intraclass correlation increased. For these points, the sensitivity of c-VFT was 0.89 and specificity was 0.97. While the c-VFT is not designed to be diagnostic nor to replace the detailed visual field analysis, this study shows that it provides a reasonable screening of the central visual field. The test can easily be used and will be made freely available to neuropsychological clinicians and researchers.

Components of Attention in Grapheme-Color Synesthesia: A Modeling Approach

Grapheme-color synesthesia is a condition where the perception of graphemes consistently and automatically evokes an experience of non-physical color. Many have studied how synesthesia affects the processing of achromatic graphemes, but less is known about the synesthetic processing of physically colored graphemes. Here, we investigated how the visual processing of colored letters is affected by the congruence or incongruence of synesthetic grapheme-color associations. We briefly presented graphemes (10-150 ms) to 9 grapheme-color synesthetes and to 9 control observers. Their task was to report as many letters (targets) as possible, while ignoring digit (distractors). Graphemes were either congruently or incongruently colored with the synesthetes' reported grapheme-color association. A mathematical model, based on Bundesen's (1990) Theory of Visual Attention (TVA), was fitted to each observer's data, allowing us to estimate discrete components of visual attention. The models suggested that the synesthetes processed congruent letters faster than incongruent ones, and that they were able to retain more congruent letters in visual short-term memory, while the control group's model parameters were not significantly affected by congruence. The increase in processing speed, when synesthetes process congruent letters, suggests that synesthesia affects the processing of letters at a perceptual level. To account for the benefit in processing speed, we propose that synesthetic associations become integrated into the categories of graphemes, and that letter colors are considered as evidence for making certain perceptual categorizations in the visual system. We also propose that enhanced visual short-term memory capacity for congruently colored graphemes can be explained by the synesthetes' expertise regarding their specific grapheme-color associations.

Taking Conjunction Search to a Higher Dimension

In visual search for conjunctions, targets are defined by combinations of features. Thus, targets might be RED VERTICAL items among RED horizontal and green VERTICAL distractors. Guided Search and similar models argue that features are conjoined only once an object is attended. However, efficient conjunction search is possible because observers can guide attention toward red and toward vertical. Real-world objects may be defined by the conjunction of many features, with no one feature defining the target. Can attention be guided to higher order conjunctions? We created 6D conjunction stimuli and varied the number of features shared between targets and distractors and the number of distractor types. RT x set size slopes range from 1.4 msec/item when two distractor types each share three features with the target to 66 msec/item when six distractor types each share five features with the target. Using different 3D conjunctions, we held distributions of features constant (1/3 of each of three colors, shapes, and orientations). We varied the grouping of distractors in order to look for evidence of simultaneous guidance by multiple attributes versus sequential grouping of subsets (Find the odd orientation in this color subset). We find that guidance and grouping may both contribute to efficient conjunction search.