Ipsilesional perceptual deficits in hemispatial neglect: Case reports

An International and Multidisciplinary Consensus on the Labeling of Spatial Neglect Using a Modified Delphi Method

Survivors of neurologic injury (most commonly stroke or traumatic brain injury) frequently experience a disorder in which contralesionally positioned objects or the contralesional features of individual objects are often left unattended or underappreciated. The disorder is known by >200 unique labels in the literature, which potentially causes confusion for patients and their families, complicates literature searches for researchers and clinicians, and promotes a fractionated conceptualization of the disorder. The objective of this Delphi was to determine if consensus (≥75% agreement) could be reached by an international and multidisciplinary panel of researchers and clinicians with expertise on the topic. To accomplish this aim, we used a modified Delphi method in which 66 researchers and/or clinicians with expertise on the topic completed at least 1 of 4 iterative rounds of surveys. Per the Delphi method, panelists were provided with results from each round prior to responding to the survey in the subsequent round with the explicit intention of achieving consensus. The panel ultimately reached consensus that the disorder should be consistently labeled spatial neglect. Based on the consensus reached by our expert panel, we recommend that researchers and clinicians use the label spatial neglect when describing the disorder in general and more specific labels pertaining to subtypes of the disorder when appropriate.

Controlling Brain State Prior to Stimulation of Parietal Cortex Prevents Deterioration of Sustained Attention

Sustained attention is a limited resource which declines during daily tasks. Such decay is exacerbated in clinical and aging populations. Inhibition of the intraparietal sulcus (IPS), using low-frequency repetitive transcranial magnetic stimulation (LF-rTMS), can lead to an upregulation of functional communication within the attention network. Attributed to functional compensation for the inhibited node, this boost lasts for tens of minutes poststimulation. Despite the neural change, no behavioral correlate has been found in healthy subjects, a necessary direct evidence of functional compensation. To understand the functional significance of neuromodulatory induced fluctuations on attention, we sought to boost the impact of LF-rTMS to impact behavior. We controlled brain state prior to LF-rTMS using high-frequency transcranial random noise stimulation (HF-tRNS), shown to increase and stabilize neuronal excitability. Using fMRI-guided stimulation protocols combining HF-tRNS and LF-rTMS, we tested the poststimulation impact on sustained attention with multiple object tracking (MOT). While attention deteriorated across time in control conditions, HF-tRNS followed by LF-rTMS doubled sustained attention capacity to 94 min. Multimethod stimulation was more effective when targeting right IPS, supporting specialized attention processing in the right hemisphere. Used in cognitive domains dependent on network-wide neural activity, this tool may cause lasting neural compensation useful for clinical rehabilitation.