Repeated application of the covert shift of attention task improves endogenous but not exogenous attention in patients with unilateral visuospatial inattention

Disengagement of attention with spatial neglect: A systematic review of behavioral and anatomical findings

The present review examined the consequences of focal brain injury on spatial attention studied with cueing paradigms, with a particular focus on the disengagement deficit, which refers to the abnormal slowing of reactions following an ipsilesional cue. Our review supports the established notion that the disengagement deficit is a functional marker of spatial neglect and is particularly pronounced when elicited by peripheral cues. Recent research has revealed that this deficit critically depends on cues that have task-relevant characteristics or are associated with negative reinforcement. Attentional capture by task-relevant cues is contingent on damage to the right temporo-parietal junction (TPJ) and is modulated by functional connections between the TPJ and the right insular cortex. Furthermore, damage to the dorsal premotor or prefrontal cortex (dPMC/dPFC) reduces the effect of task-relevant cues. These findings support an interactive model of the disengagement deficit, involving the right TPJ, the insula, and the dPMC/dPFC. These interconnected regions play a crucial role in regulating and adapting spatial attention to changing intrinsic values of stimuli in the environment.

Digital Therapeutics for the Egocentric and Allocentric Neglects in Patients with Brain Injury: A Mini Review

Various therapeutic approaches have been developed for neglect. Many studies have demonstrated the effect of digital therapeutics (DTx) on neglect. However, few studies have reported the effects of DTx on egocentric and allocentric neglect. The differentiation of types of neglect and separate interventions is crucial in the rehabilitation process. In this article, seven studies on DTx on egocentric and allocentric neglect were reviewed. DTx, which was employed in these studies, could be classified as follows: (1) software adaptation in traditional treatment, (2) VR game using the head-mount display as treatment, and (3) the development of a new digital program like ReMoVES. In addition, more studies and more effective results were reported for egocentric neglect than for allocentric neglect. In future studies, each effect on egocentric and allocentric neglect should be identified in detail with the appropriate use of differential evaluation and long-term application of independent DTx.

Is recovery from left-sided neglect based on changes in automatic attention? An auditory event related potentials study

An automatic spatial attention deficit is the primary deficit in neglect. However, the cognitive processes enabling recovery from neglect have rarely been studied. We used event-related potentials (ERP) to analyze if recovery is based on changes in automatic attention components. Twelve sub-acute patients with left visuospatial neglect were included. They received 3 weeks of intensive treatment. ERPs were recorded using two auditory paradigms: either a tone was presented randomly to the right or left ear (ATP) or as a Posner paradigm (PP) with left to right and vice versa moving cue tones and validly and invalidly cued target tones. Patients improved significantly on neuropsychological tests and neurological scales. For the ATP, no differences were observed related to the side of stimulation, but the auditory PP showed characteristic results, that is, smaller amplitudes for left-sided targets and higher amplitudes for invalid trials. Both paradigms revealed a treatment effect, but no changes were found in the amplitudes for the two target sides, which would be expected if the treatment would affect the automatic attention bias. Recovery from neglect seems not to be associated with changes in the automatic spatial attention bias, arguing that recovery might be due to higher cognitive compensatory processes.

Effect of motor tasks with left monocular eyeglasses on visual search and line-bisection performance in people with left unilateral spatial neglect

Training with an eyepatch or eyeglasses is one of the effective approaches for unilateral spatial neglect (USN), and it usually uses a device that covers the right side. However, few approaches are available for the left side. In this study, we examine the effect of motor tasks with left/right monocular eyeglasses on visual search and line-bisection performance in people with left USN. Seven participants with left USN admitted to convalescent hospitals were included. We conducted the Bells test, line-crossing test, and line-bisection test of the behavioral inattention test before/after the motor task. Our analyses focused on the improvement or decline in these assessment scores and the achievement/errors/non-smoothness scores of the motor task. When using the left monocular eyeglasses, the percentages of participants categorized as "improvement," "unchanged," and "decline" were 71.4%, 28.6%, and 0%, respectively (when using the right one they were 14.3%, 85.7%, and 0%). In the motor task, when using the left monocular eyeglasses, total achievement scores in five of seven participants were greater than those when using the right one, and they performed efficiently with fewer movement errors. These results suggest that training with left monocular eyeglasses might improve visual search performance in people with left USN.

Audiospatial evoked potentials for the assessment of spatial attention deficits in patients with severe cerebrovascular accidents

INTRODUCTION

Neuropsychological assessment of spatial orientation in post-acute patients with large brain lesions is often limited due to additional cognitive disorders like aphasia, apraxia, or reduced responsiveness.

METHODS

To cope with these limitations, we developed a paradigm using passive audiospatial event-related potentials (pAERPs): Participants were requested to merely listen over headphones to horizontally moving tones followed by a short tone ("target"), presented either on the side to which the cue moved or on the opposite side. Two runs of 120 trials were presented and we registered AERPs with two electrodes, mounted at C3 and C4. Nine sub-acute patients with large left hemisphere (LH) or right hemisphere (RH) lesions and nine controls participated.

RESULTS

Patients had no problems completing the assessment. RH patients showed a reduced N100 for left-sided targets in all conditions. LH patients showed a diminished N100 for invalid trials and contralesional targets.

CONCLUSION

Measuring AERPs for moving auditory cues and with two electrodes allows investigating spatial attentional deficits in patients with large RH and LH lesions, who are often unable to perform clinical tests. Our procedure can be implemented easily in an acute and rehabilitation setting and might enable investigating spatial attentional processes even in patients with minimal conscious awareness.