Improvement of hemispatial neglect with cold-water calorics: An electrophysiological test of the arousal hypothesis of neglect

1997 ◽  
Vol 3 (4) ◽  
pp. 394-402 ◽  
Author(s):  
H.J. STORRIE-BAKER ◽  
S.J. SEGALOWITZ ◽  
S.E. BLACK ◽  
J.A.G. McLEAN ◽  
N. SULLIVAN
Keyword(s):  
Right Hemisphere ◽  
Cold Water ◽  
Eye Gaze ◽  
Cortical Activation ◽  
Central Position ◽  
Hemispatial Neglect ◽  
Caloric Stimulation ◽  
Eeg Changes ◽  
The Right ◽  
Ice Water

Introducing ice-water into the left ear of right-brain-damaged patients attenuates unilateral neglect symptoms. By examining EEG changes over each hemisphere during this procedure, we were able to test a hypothesis concerning the mechanism of cold-water calorics and the attention–arousal hypothesis of hemispatial neglect. We present a case study of an 83-year-old woman with a massive right-hemisphere CVA exhibiting severe hemispatial neglect. Caloric stimulation produced a leftward eye deviation to central position, and a temporary partial remission of neglect symptoms. Significant changes in EEG activation indicated a central mechanism associated with the regularization of eye gaze. Caloric stimulation also produced a significant interaction between EEG frequency band and hemisphere, indicating that while both hemispheres increased in cortical activation, the right hemisphere increase was significantly greater. This supports the activation–arousal hypothesis of neglect over the mutual inhibition model. (JINS, 1997, 3, 394–402.)

Caloric stimulation in neglect: Evaluation of response as a function of neglect type

2003 ◽  
Vol 9 (7) ◽  
pp. 983-988 ◽  
Author(s):  
JOHN C. ADAIR ◽  
DUK L. NA ◽  
RONALD L. SCHWARTZ ◽  
KENNETH M. HEILMAN
Keyword(s):  
Right Hemisphere ◽  
Line Bisection ◽  
Differential Performance ◽  
Caloric Stimulation ◽  
The Right ◽  
Ice Water

Contralesional neglect may be induced by either unawareness of contralesional stimuli (attentional neglect, AN) or failure to act in contralesional space (intentional neglect, IN). We examined whether contralesional cold caloric stimulation differentially affects ANversusIN. Patients with left-sided neglect (n= 16) from right-hemisphere lesions performed target cancellation and line bisection tasks. Using a video-based apparatus that reverses the right and left side of stimuli, patients with abnormal cancellation performance were divided into those with AN and those with IN. The 5 subjects with normal cancellation performance but rightward bisection bias were also separated into 2 neglect groups. Subjects performed cancellation or bisection tasks before and immediately after irrigation of the left auditory canal with ice water. Caloric stimulation induced brisk rightward nystagmus in all subjects. Subjects with AN cancelled more left-sided targets after stimulation than those with IN (p= .02). Whereas caloric stimulation significantly shifted bisection error leftward for both IN and AN groups (p< .0001), AN patients exhibited a greater magnitude of shift than the IN patients. While the basis for differential performance remains undefined, the data indicate that caloric stimulation influences AN more than IN. (JINS, 2003,9, 983–988.)

An Analysis of Temporal Electroemeeptialograpliic Patterning Prior to Initiation of the Arm Curl

1992 ◽  
Vol 14 (1) ◽  
pp. 87-100
Author(s):  
Timothy Gannon ◽  
Daniel Landers ◽  
Karla Kubitz ◽  
Walter Salazar ◽  
Steven Petruizello
Keyword(s):  
Right Hemisphere ◽  
Attentional Focus ◽  
Self Report ◽  
Emg Activity ◽  
Cognitive Differences ◽  
Eeg Activity ◽  
Muscular Exertion ◽  
Task Differences ◽  
Eeg Changes ◽  
The Right

To determine if the different EEG patterns noted in previous studies were due to between-task differences in muscular exertion, the present study examined the electroencephalographic (EEG) activity in the seconds prior to either holding the weight (without lifting) or executing an arm lift at either 25% or 95% of the subject's one-repetition maximum value. Temporal EEG and tempomandibular and trapezius electromyography (EMG) measures were obtained from subjects (N=20) in the half-second period during the holding of the weight or immediately before lifting the weight. The degree of attentional focus on the task was quantified through self-report measures after each set of trials. EMG activity was not significantly different between the hold and lift phases. The self-report degree of attentional focus was higher in the lift phase, compared to the hold phase, for both 25% and 95% conditions (p<.01). Increases in EEG activity for the 25% condition were observed between the hold and lift phases at 4 Hz (p<.003). This extended to 10 additional frequencies in the 95% condition (p<.004), with beta (13 to 30 Hz) activity greater in the right hemisphere (p<.004). Because there were no EMG differences between phases or conditions» it was concluded that the EEG changes were reflective of cognitive differences associated with attending to tasks that differed in level of muscular exertion.

scholarly journals Corticospinal Excitability During a Perspective Taking Task as Measured by TMS-induced Motor Evoked Potentials

2021 ◽  
Author(s):  
Janet Brenya ◽  
Katherine Chavarria ◽  
Elizabeth Murray ◽  
Karen Kelly ◽  
Anjel Friest ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Perspective Taking ◽  
Right Hemisphere ◽  
Motor Evoked Potentials ◽  
Conscious Experience ◽  
Cortical Activation ◽  
Person Perspective ◽  
Third Person ◽  
Third Person Perspective ◽  
The Right

Only by understanding the ability to take third-person perspective can we begin to elucidate the neural processes responsible for one&rsquo;s inimitable conscious experience. The current study examined differences in hemispheric laterality during a first-person perspective (1PP) and third-person perspective (3PP) taking task, when using Transcranial Magnetic Stimulation (TMS). Participants were asked to take either the 1PP or 3PP when identifying the number of spheres in a virtual scene. During this task, single-pulse TMS was delivered to the motor cortex of both the left and right hemispheres of 10 healthy volunteers. Measures of TMS-induced motor-evoked potentials (MEPs) of the contralateral abductor pollicis brevis (APB) were employed as an indicator of lateralized cortical activation. The data suggest that the right hemisphere is more important in discriminating between 1PP and 3PP. These data add a novel method for determining perspective taking and add to the literature supporting the role of the right hemisphere in meta representation.

scholarly journals Cortical Activation in Mental Rotation and the Role of the Corpus Callosum: Observations in Healthy Subjects and Split-Brain Patients

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1953
Author(s):  
Chiara Pierpaoli ◽  
Mojgan Ghoushi ◽  
Nicoletta Foschi ◽  
Simona Lattanzi ◽  
Mara Fabri ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Mental Rotation ◽  
Right Hemisphere ◽  
Body Part ◽  
Cortical Activation ◽  
Control Subjects ◽  
Healthy Control ◽  
The Difference ◽  
The Right

The mental rotation (MR) is an abstract mental operation thanks to which a person imagines rotating an object or a body part to place it in an other position. The ability to perform MR was belived to belong to the right hemisphere for objects, and to the left for one’s ownbody images. Mental rotation is considered to be basic for imitation with the anatomical perspective, which in turn is needed for social interactions and learning. Altered imitative performances have been reported in patients with resections or microstructure alterations of the corpus callosum (CC). These patients also display a reduced MR ability compared to control subjects, as shown in a recent behavioral study. The difference was statistically significant, leading us to hypothesize a role of the CC to integrate the two hemispheres’ asymmetric functions. The present study was designed to detect, by means of a functional MRI, the cortical activation evoked during an MR task in healthy control subjects and callosotomized patients. The results suggest that performing MR requires activation of opercular cortex and inferior parietal lobule in either hemispheres, and likely the integrity of the CC, thus confirming that the main brain commissure is involved in cognitive functions.

scholarly journals Abnormal Cortical Activation Patterns Among Chinese-Speaking Schizophrenia Patients During Category and Letter Verbal Fluency Tasks Revealed by Multi-Channel Functional Near-Infrared Spectroscopy

2021 ◽  
Vol 12 ◽  
Author(s):  
Juan Li ◽  
Junlin Mu ◽  
Chenyu Shen ◽  
Guanqun Yao ◽  
Kun Feng ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Left Hemisphere ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Right Hemisphere ◽  
Cortical Activation ◽  
Chinese Patients ◽  
Healthy Controls ◽  
Functional Near Infrared Spectroscopy ◽  
The Right

Background: Functional near-infrared spectroscopy (fNIRS) has many advantages over other neuroimaging modalities for routine measurement of task-dependent cortical activation, but most fNIRS studies of schizophrenia have used letter fluency tasks (LFTs). Further, performances on category fluency tasks (CFTs) and LFTs may be distinct in Chinese patients due to the unique semantic features of Chinese written characters. To identify unique disease biomarkers measurable by fNIRS in Chinese schizophrenia patients, this study compared cortical oxygenated hemoglobin changes ([oxy-Hb]) during a Chinese LFT and CFT between patients and healthy controls.Methods: Inpatients of the Second Affiliated Hospital of Xinxiang Medical University were recruited from Match 2020 to July 2021. The Positive and Negative Symptom Scale (PANSS) was used to evaluate psychiatric symptoms. Dynamic changes in [oxy-Hb], an indicator of neural activity, were measured during CFT and LFT performance by 52-channel fNIRS.Results: Forty-seven schizophrenia inpatients and 29 healthy controls completed all tests. Schizophrenia patients showed significant cortical activation at 15 channels covering the left hemisphere and 17 channels over the right hemisphere during the CFT. During the LFT, activity was significantly increased at only six channels, all over the left hemisphere (FDR P &lt; 0.05). In healthy controls, significant [oxy-Hb] increases were found at 24 channels over the left hemisphere and 19 channels over the right hemisphere during CFT. While during the LFT, the significant increases were found at 7 channels all over the left hemisphere (FDR P &lt; 0.05). When years of education was included as a covariate, the schizophrenia group demonstrated no significant hypoactivation relative to healthy controls at any channel after FDR correction (FDR P &lt; 0.05) during CFT while demonstrated significant hypoactivation at channel 11 during LFT (FDR P &lt; 0.05). There were no significant associations between PANSS scores and [oxy-Hb] changes after FDR correction (FDR P &lt; 0.05).Conclusions: Left lateralization during CFT was reduced among schizophrenia patients and may be related to the semantic deficit. The Chinese-CFT could be a more sensitive indicator of frontal-temporal dysfunction in schizophrenia.

Clustering and switching in divergent thinking: Neurophysiological correlates underlying flexibility during idea generation

2021 ◽  
Author(s):  
Serena Mastria ◽  
Sergio Agnoli ◽  
Marco Zanon ◽  
Selcuk Acar ◽  
Mark Runco ◽  
...  
Keyword(s):  
Divergent Thinking ◽  
Right Hemisphere ◽  
Idea Generation ◽  
Cortical Activation ◽  
Cognitive Resources ◽  
Alpha Band ◽  
Everyday Objects ◽  
Posterior Parietal ◽  
Eeg Alpha ◽  
The Right

EEG alpha synchronization, especially in posterior parietal cortical regions of the right hemisphere, is indicative of high internal processing demands that are typically involved in divergent thinking (DT). During the course of DT, as ideation proceeds, ideas tend to become more creative, being more likely to be drawn from new conceptual categories through the use of the cognitive mechanism of flexibility. The present study investigated whether EEG alpha synchronization can be modulated by flexibility in DT by comparing cortical activation patterns during the switch of category (switching) and the stay in the same category (clustering). Twenty participants were required to generate alternative uses of everyday objects during EEG recording. Differential results were specifically found in the lower alpha band (8-10 Hz): whereas clustering showed synchronization typically lateralized in the right posterior parietal areas, switching induced posterior parietal synchronization over both right and left hemispheres. These findings indicate that the two distinct cognitive mechanisms subsuming flexibility (switching and clustering) are associated with a different hemispheric modulation of lower alpha activity, as switching, in comparison to clustering, is related to higher power in the lower alpha band over the left hemisphere. Switching in comparison to clustering may thus require a larger investment of cognitive resources due to the exploratory process of moving from one semantic conceptual category to another in the course of creative ideation.

scholarly journals Is Grasping Impaired in Hemispatial Neglect?

2002 ◽  
Vol 13 (1-2) ◽  
pp. 17-28 ◽  
Author(s):  
Monika Harvey ◽  
Stephen R. Jackson ◽  
Roger Newport ◽  
Tanja Krämer ◽  
D. Llewlyn Morris ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Target Object ◽  
Cerebral Stroke ◽  
Hemispatial Neglect ◽  
Grip Aperture ◽  
Maximum Grip Aperture ◽  
Path Curvature ◽  
The Right ◽  
Path Deviation ◽  
Maximum Grip

Patients with right unilateral cerebral stroke, four of which showed acute hemispatial neglect, and healthy aged-matched controls were tested for their ability to grasp objects located in either right or left space at near or far distances. Reaches were performed either in free vision or without visual feedback from the hand or target object. It was found that the patient group showed normal grasp kinematics with respect to maximum grip aperture, grip orientation, and the time taken to reach the maximum grip aperture. Analysis of hand path curvature showed that control subjects produced straighter right hand reaches when vision was available compared to when it was not. The right hemisphere lesioned patients, however, showed similar levels of curvature in each of these conditions. No behavioural differences, though, could be found between right hemisphere lesioned patients with or without hemispatial neglect on either grasp parameters, path deviation or temporal kinematics.

scholarly journals FOPR test: a virtual reality-based technique to assess field of perception and field of regard in hemispatial neglect

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tae-Lim Kim ◽  
Kwanguk Kim ◽  
Changyeol Choi ◽  
Ji-Yeong Lee ◽  
Joon-Ho Shin
Keyword(s):  
Virtual Reality ◽  
Right Hemisphere ◽  
Support Vector ◽  
Hemispatial Neglect ◽  
Stroke Patients ◽  
Altman Plot ◽  
Bland Altman Plot ◽  
Visuospatial Function ◽  
Conventional Tests ◽  
The Right

Abstract Background We previously proposed a novel virtual reality-based method to assess human field of perception (FOP) and field of regard (FOR), termed the FOPR test. This study assessed the diagnostic validity of the FOPR test for hemispatial neglect (HSN). Methods We included 19 stroke patients with a lesion in the right hemisphere and with HSN (HSN+SS), 22 stroke patients with a lesion in the right hemisphere and without HSN (HSN−SS), and 22 healthy controls aged 19–65 years. The success rate (SR) and response time (RT) in the FOPR test for both FOP and FOR were assessed (FOP-SR, FOR-SR, FOP-RT, and FOR-RT, respectively). Using a Bland–Altman plot, agreements between the FOPR test and conventional tests were confirmed, and the FOPR test accuracy was verified using the support vector machine (SVM). Measured values were analysed using ANOVA and Kruskall–Wallis tests for group comparison. Results The Bland–Altman plot showed good agreement between FOPR test and conventional tests; individuals within 95% agreement limits were within the range of 94.8–100.0%. The SVM classification accuracy, using FOP and FOR variables from the left hemispace, ranged from 83.3 to 100.0% in a binary classification (HSN vs non-HSN). The FOPR test demonstrated differences in SR and RT for both FOP and FOR across the groups. Conclusion The FOPR test was valid for the HSN diagnosis and provided quantitative and intuitive information regarding visuospatial function. Furthermore, it might enhance our understanding of visuospatial function including HSN by applying the time relative component and concepts of perception and exploration, FOP and FOR. Trial registration: NCT03463122. Registered 13 March 2018, retrospectively registered.

scholarly journals Disruptions of the Human Connectome Associated With Hemispatial Neglect

Neurology ◽  
2022 ◽  
Vol 98 (2) ◽  
pp. e107-e114
Author(s):  
Sadhvi Saxena ◽  
Zafer Keser ◽  
Chris Rorden ◽  
Leonardo Bonilha ◽  
Julius Fridriksson ◽  
...  
Keyword(s):  
White Matter ◽  
Parietal Cortex ◽  
Right Hemisphere ◽  
Temporal Cortex ◽  
Brain Regions ◽  
Horizontal Line ◽  
Hemispatial Neglect ◽  
White Matter Tracts ◽  
The Right ◽  
Contralesional Side

Background and ObjectivesHemispatial neglect is a heterogeneous and complex disorder that can be classified by frame of reference for “left” vs “right,” including viewer-centered neglect (VCN, affecting the contralesional side of the view), stimulus-centered neglect (SCN, affecting the contralesional side of the stimulus, irrespective of its location with respect to the viewer), or both. We investigated the effect of acute stroke lesions on the connectivity of neural networks that underlie VCN or SCN.MethodsA total of 174 patients within 48 hours of acute right hemispheric infarct underwent a detailed hemispatial neglect assessment that included oral reading, scene copy, line cancellation, gap detection, horizontal line bisection tests, and MRI. Each patient's connectivity map was generated. We performed a linear association analysis between network connectivity strength and continuous measures of neglect to identify lesion-induced disconnections associated with the presence or severity of VCN and SCN. Results were corrected for multiple comparisons.ResultsAbout 42% of the participants with right hemisphere stroke had at least one type of neglect. The presence of any type of neglect was associated with lesions to tracts connecting the right inferior parietal cortex, orbitofrontal cortex, and right thalamus to other right-hemispheric structures. VCN only was strongly associated with tracts connecting the right putamen to other brain regions and tracts connecting right frontal regions with other brain regions. The presence of both types of neglect was most strongly associated with tracts connecting the right inferior and superior parietal cortex to other brain regions and those connecting left or right mesial temporal cortex to other brain regions.DiscussionOur study provides new evidence for the specific white matter tracts where disruption can cause hemispatial neglect in a relatively large number of participants and homogeneous time after onset. We obtained MRI and behavioral testing acutely, before the opportunity for rehabilitation or substantial recovery.Classification of EvidenceThis study provides Class II evidence that damage to specific white matter tracts identified on MRI are associated with the presence of neglect following right hemispheric stroke.

scholarly journals Dual-Task in Large Perceptual Space Reveals Subclinical Hemispatial Neglect

2020 ◽  
Vol 26 (10) ◽  
pp. 993-1005
Author(s):  
Sanna Villarreal ◽  
Matti Linnavuo ◽  
Raimo Sepponen ◽  
Outi Vuori ◽  
Hanna Jokinen ◽  
...  
Keyword(s):  
Patient Group ◽  
Functional Disability ◽  
Right Hemisphere ◽  
Task Complexity ◽  
Reaction Times ◽  
Hemispatial Neglect ◽  
Dual Tasks ◽  
Significant Group ◽  
Large Screen ◽  
The Right

AbstractObjective:Both clinically observable and subclinical hemispatial neglect are related to functional disability. The aim of the present study was to examine whether increasing task complexity improves sensitivity in assessment and whether it enables the identification of subclinical neglect.Method:We developed and compared two computerized dual-tasks, a simpler and a more complex one, and presented them on a large, 173 × 277 cm screen. Participants in the study included 40 patients with unilateral stroke in either the left hemisphere (LH patient group, n = 20) or the right hemisphere (RH patient group, n = 20) and 20 healthy controls. In addition to the large-screen tasks, all participants underwent a comprehensive neuropsychological assessment. The Bells Test was used as a traditional paper-and-pencil cancellation test to assess neglect.Results:RH patients made significantly more left hemifield omission errors than controls in both large-screen tasks. LH patients’ omissions did not differ significantly from those of the controls in either large-screen task. No significant group differences were observed in the Bells Test. All groups’ reaction times were significantly slower in the more complex large-screen task compared to the simpler one. The more complex large-screen task also produced significantly slower reactions to stimuli in the left than in the right hemifield in all groups.Conclusions:The present results suggest that dual-tasks presented on a large screen sensitively reveal subclinical neglect in stroke. New, sensitive, and ecologically valid methods are needed to evaluate subclinical neglect.

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