Visual exploration pattern in hemineglect

The analysis of eye movement parameters in visual neglect such as cumulative fixation duration, saccade amplitude, or the numbers of saccades has been used to probe attention deficits in neglect patients, since the pattern of exploratory eye movements has been taken as a strong index of attention distribution. The current overview of the literature of visual neglect has its emphasis on studies dealing with eye movement and exploration analysis. We present our own results in 15 neglect patients. The free exploration behavior was analyzed in these patients presenting 32 naturalistic color photographs of everyday scenes. Cumulative fixation duration, spatial distribution of fixations in the horizontal and vertical plane, the number and amplitude of exploratory saccades was analyzed and compared with the results of an age-matched control group. A main result of our study was that in neglect patients, fixation distribution of free exploration of natural scenes is not only influenced by the left-right bias in the horizontal direction but also by the vertical directio

Screening for language disorders in stroke: german validation of the language screening test (last)

Background: Screening of aphasia in acute stroke is crucial for directing patients to early language therapy. The Language Screening Test (LAST), originally developed in French, is a validated language screening test that allows detection of a language deficit within a few minutes. The aim of the present study was to develop and validate two parallel German versions of the LAST. Methods: The LAST includes subtests for naming, repetition, automatic speech, and comprehension. For the translation into German, task constructs and psycholinguistic criteria for item selection were identical to the French LAST. A cohort of 101 stroke patients were tested, all of whom were native German speakers. Validation of the LAST was based on (1) analysis of equivalence of the German versions, which was established by administering both versions successively in a subset of patients, (2) internal validity by means of internal consistency analysis, and (3) external validity by comparison with the short version of the Token Test in another subset of patients. Results: The two German versions were equivalent as demonstrated by a high intraclass correlation coefficient of 0.91. Furthermore, an acceptable internal structure of the LAST was found (Cronbach's α = 0.74). A highly significant correlation (r = 0.74, p < 0.0001) between the LAST and the short version of the Token Test indicated good external validity of the scale. Conclusion: The German version of the LAST, available in two parallel versions, is a new and valid language screening test in stroke

The spatial distribution of perseverations in neglect patients during a nonverbal fluency task depends on the integrity of the right putamen

Deficient inhibitory control leading to perseverative behaviour is often observed in neglect patients. Previous studies investigating the relationship between response inhibition and visual attention have reported contradictory results: some studies found a linear relationship between neglect severity and perseverative behaviour whereas others could not replicate this result. The aim of the present study was to shed further light on the interplay between visual attention and response inhibition in neglect, and to investigate the neural underpinnings of this interplay. We propose the use of the Five-Point Test, a test commonly used to asses nonverbal fluency, as a novel approach in the context of neglect. In the Five-Point Test, participants are required to generate as many different designs as possible, by connecting dots within forty rectangles. We hypothesised that, because of its clear definition of perseverative errors, the Five-Point Test would accurately assess both visual attention as well as perseverative behaviour. We assessed 46 neglect patients with right-hemispheric stroke, and performed voxel-based lesion-symptom mapping (VLSM) to identify neural substrates of perseverative behaviour as well as the spatial distribution of perseverations. Our results showed that the Five-Point Test can reliably measure neglect and perseverative behaviour. We did not find any significant relationship between neglect severity and the frequency of perseverations. However, within the subgroup of neglect patients who displayed perseverative behaviour, the spatial distribution of perseverations significantly depended on the integrity of the right putamen. We discuss the putative role of the putamen as a potential subcortical hub to modulate the complex integration between visual attention and response inhibition processes

Cognitive Impairment in Multiple Sclerosis: Clinical Manifestation, Neuroimaging Correlates, and Treatment

Cognitive impairment is found in up to 70% of patients with multiple sclerosis (MS). Once thought of as a variant of subcortical dementia with a characteristic set of deficits, we now know that MS-related cognitive impairment can have many faces. This conceptual change in neuropsychology is embedded in a paradigm shift in the neuroscientific understanding of MS over the past 25 years: Partly based on modern neuroimaging techniques, the classical view of MS as an inflammatory demyelinating disease affecting the white matter of the central nervous system has been extended. In particular, many studies have shown that the MS pathology also includes neurodegeneration, and that gray matter structures such as the cerebral cortex can also show focal lesions, atrophy, or both. The authors present an updated summary of the clinical manifestation and neuroimaging correlates of cognitive impairment in MS, and discuss the relatively few treatment options available to date

Bottom-up Visual Integration in the Medial Parietal Lobe

Largely based on findings from functional neuroimaging studies, the medial parietal lobe is known to contribute to internally directed cognitive processes such as visual imagery or episodic memory. Here, we present 2 patients with behavioral impairments that extend this view. Both had chronic unilateral lesions of nearly the entire medial parietal lobe, but in opposite hemispheres. Routine neuropsychological examination conducted >4 years after the onset of brain damage showed little deficits of minor severity. In contrast, both patients reported persistent unusual visual impairment. A comprehensive series of tachistoscopic experiments with lateralized stimulus presentation and comparison with healthy participants revealed partial visual hemiagnosia for stimuli presented to their contralesional hemifield, applying inferential single-case statistics to evaluate deficits and dissociations. Double dissociations were found in 4 experiments during which participants had to integrate more than one visual element, either through comparison or formation of a global gestalt. Against the background of recent neuroimaging findings, we conclude that of all medial parietal structures, the precuneus is the most likely candidate for a crucial involvement in such bottom-up visual integration

Auditory spatial cueing reduces neglect after right-hemispheric stroke: a proof of concept study

Spatial neglect after right-hemispheric stroke, characterized by the failure to attend or respond to the contralesional space, is a strong negative outcome predictor. Neglect is a supramodal syn-drome affecting not only the visual but also the auditory modality. Preliminary studies used this audio-visual cross-modal effect to show short-lasting effects on attention towards the neglected space. The aim of the present study was to introduce a new technique of auditory stimulation combining the unspecific effect of music (i.e. patients choose their preferred music) with the effects of auditory spatial cueing (i.e. the music is presented dynamically as moving from right to left). The effect of this new auditory stimulation technique was investigated in two proof-of-concept experiments using repeated-measures, cross-over designs including overall 21 patients with visual neglect after a first right-hemispheric stroke. In experiment I (n=9), neglect patients showed a significantly larger improvement in Letter Cancellation after listening to preferred music with than without auditory spatial cueing. After granting the feasibility of this new auditory stimulation technique, we investigated the long-term aftereffects in experiment II (n=12). Herefore, we used video-oculography during Free Visual Exploration, a sensitive and reliable tool to assess spatial attention over time. Listening to music with auditory spatial cueing – as compared to music without auditory spatial cueing – significantly improved neglect severity in terms of visual exploration behaviour for up to 3h. A voxel-based-lesion-symptom mapping analysis over all patients revealed that the response variability in listening to music with auditory spatial cueing is determined by the integrity of the right inferior parietal lobule, the second branch of the superior longitudinal fascicle, and parieto-parietal callosal fibres. Our study shows that listening to music with auditory spatial cueing significantly reduces neglect severity and has the potential to be used as an add-on in the neurorehabilitation of neglect

Screening for Language Disorders in Stroke: German Validation of the Language Screening Test (LAST)

Background: Screening of aphasia in acute stroke is crucial for directing patients to early language therapy. The Language Screening Test (LAST), originally developed in French, is a validated language screening test that allows detection of a language deficit within a few minutes. The aim of the present study was to develop and validate two parallel German versions of the LAST. Methods: The LAST includes subtests for naming, repetition, automatic speech, and comprehension. For the translation into German, task constructs and psycholinguistic criteria for item selection were identical to the French LAST. A cohort of 101 stroke patients were tested, all of whom were native German speakers. Validation of the LAST was based on (1) analysis of equivalence of the German versions, which was established by administering both versions successively in a subset of patients, (2) internal validity by means of internal consistency analysis, and (3) external validity by comparison with the short version of the Token Test in another subset of patients. Results: The two German versions were equivalent as demonstrated by a high intraclass correlation coefficient of 0.91. Furthermore, an acceptable internal structure of the LAST was found (Cronbach's α = 0.74). A highly significant correlation (r = 0.74, p Conclusion: The German version of the LAST, available in two parallel versions, is a new and valid language screening test in stroke