scholarly journals Poststroke acute dysexecutive syndrome, a disorder resulting from minor stroke due to disruption of network dynamics

2020 ◽  
Vol 117 (52) ◽  
pp. 33578-33585
Author(s):  
Elisabeth B. Marsh ◽  
Christian Brodbeck ◽  
Rafael H. Llinas ◽  
Dania Mallick ◽  
Joshua P. Kulasingham ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Task Complexity ◽  
Network Dynamics ◽  
Reaction Times ◽  
Fusiform Gyrus ◽  
Minor Stroke ◽  
Matching Task ◽  
Stroke Patients ◽  
Activation Patterns ◽  
Dysexecutive Syndrome

Stroke patients with small central nervous system infarcts often demonstrate an acute dysexecutive syndrome characterized by difficulty with attention, concentration, and processing speed, independent of lesion size or location. We use magnetoencephalography (MEG) to show that disruption of network dynamics may be responsible. Nine patients with recent minor strokes and eight age-similar controls underwent cognitive screening using the Montreal cognitive assessment (MoCA) and MEG to evaluate differences in cerebral activation patterns. During MEG, subjects participated in a visual picture–word matching task. Task complexity was increased as testing progressed. Cluster-based permutation tests determined differences in activation patterns within the visual cortex, fusiform gyrus, and lateral temporal lobe. At visit 1, MoCA scores were significantly lower for patients than controls (median [interquartile range] = 26.0 [4] versus 29.5 [3], P = 0.005), and patient reaction times were increased. The amplitude of activation was significantly lower after infarct and demonstrated a pattern of temporal dispersion independent of stroke location. Differences were prominent in the fusiform gyrus and lateral temporal lobe. The pattern suggests that distributed network dysfunction may be responsible. Additionally, controls were able to modulate their cerebral activity based on task difficulty. In contrast, stroke patients exhibited the same low-amplitude response to all stimuli. Group differences remained, to a lesser degree, 6 mo later; while MoCA scores and reaction times improved for patients. This study suggests that function is a globally distributed property beyond area-specific functionality and illustrates the need for longer-term follow-up studies to determine whether abnormal activation patterns ultimately resolve or another mechanism underlies continued recovery.

scholarly journals Bilaterally Reduced Rolandic Beta Band Activity in Minor Stroke Patients

2021 ◽  
Author(s):  
Joshua P Kulasingham ◽  
Christian Brodbeck ◽  
Sheena Khan ◽  
Elisabeth B Marsh ◽  
Jonathan Z Simon
Keyword(s):  
Sensorimotor Cortex ◽  
Reaction Times ◽  
Minor Stroke ◽  
Button Press ◽  
Beta Band ◽  
Stroke Patients ◽  
Potential Biomarker ◽  
Beta Power ◽  
Motor Dexterity ◽  
Band Activity

Objective: Stroke patients with hemiparesis display decreased beta band (13-25 Hz) rolandic activity, correlating to impaired motor function. However, patients without significant weakness, with small lesions far from sensorimotor cortex, nevertheless exhibit bilateral decreased motor dexterity and slowed reaction times. We investigate whether these minor stroke patients also display abnormal beta band activity. Methods: Magnetoencephalographic (MEG) data were collected from nine minor stroke patients (NIHSS < 4) without significant hemiparesis, at ~1 and ~6 months postinfarct, and eight age-similar controls. Rolandic relative beta power during matching tasks and resting state, and Beta Event Related (De)Synchronization (ERD/ERS) during button press responses were analyzed. Results: Regardless of lesion location, patients had significantly reduced relative beta power and ERS compared to controls. Abnormalities persisted over visits, and were present in both ipsi- and contra-lesional hemispheres, consistent with bilateral impairments in motor dexterity and speed. Conclusions: Minor stroke patients without severe weakness display reduced rolandic beta band activity in both hemispheres, which may be linked to bilaterally impaired dexterity and processing speed, implicating global connectivity dysfunction affecting sensorimotor cortex. Significance: Rolandic beta band activity may be a potential biomarker and treatment target, even for minor stroke patients with small lesions far from sensorimotor areas.

scholarly journals Cerebral trauma-induced dyschromatopsia in the left hemifield: case presentation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yoko Mase ◽  
Yoshitsugu Matsui ◽  
Eriko Uchiyama ◽  
Hisashi Matsubara ◽  
Masahiko Sugimoto ◽  
...  
Keyword(s):  
Visual Field ◽  
Color Vision ◽  
Temporal Lobe ◽  
Fusiform Gyrus ◽  
Ganglion Cell Complex ◽  
Automated Perimetry ◽  
Subjective Symptoms ◽  
Anterior Temporal Lobe ◽  
Case Presentation ◽  
Cerebral Trauma

Abstract Background Acquired color anomalies caused by cerebral trauma are classified as either achromatopsias or dyschromatopsias (Zeki, Brain 113:1721–1777, 1990). The three main brain regions stimulated by color are V1, the lingual gyrus, which was designated as human V4 (hV4), and the fusiform gyrus, designated as V4α. (Zeki, Brain 113:1721–1777, 1990). An acquired cerebral color anomaly is often accompanied by visual field loss (hemi- and quadrantanopia), facial agnosia, prosopagnosia, visual agnosia, and anosognosia depending on the underlying pathology (Bartels and Zeki, Eur J Neurosci 12:172–193, 2000), (Meadows, Brain 97:615–632, 1974), (Pearman et al., Ann Neurol 5:253–261, 1979). The purpose of this study was to determine the characteristics of a patient who developed dyschromatopsia following a traumatic injury to her brain. Case presentation The patient was a 24-year-old woman who had a contusion to her right anterior temporal lobe. After the injury, she noticed color distortion and that blue objects appeared green in the left half of the visual field. Although conventional color vision tests did not detect any color vision abnormalities, short wavelength automated perimetry (SWAP) showed a decrease in sensitivity consistent with a left hemi-dyschromatopsia. Magnetic resonance imaging (MRI) detected abnormalities in the right fusiform gyrus, a part of the anterior temporal lobe. At follow-up 14 months later, subjective symptoms had disappeared, but the SWAP abnormalities persisted and a thinning of the sectorial ganglion cell complex (GCC) was detected. Conclusion The results indicate that although the subjective symptoms resolved early, a reduced sensitivity of SWAP remained and the optical coherence tomography (OCT) showed GCC thinning. We conclude that local abnormalities in the anterior section of fusiform gyrus can cause mild cerebral dyschromatopsia without other symptoms. These findings indicate that it is important to listen to the symptoms of the patient and perform appropriate tests including the SWAP and OCT at the early stage to objectively prove the presence of acquired cerebral color anomaly.

Abstract 82: Differences Between Caucasians and Asians in Intracranial Arterial Stenosis Among TIA and Minor Stroke Patients: Comparisons of Two Contemporary Cohorts

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Xinyi Leng ◽  
Robert Hurford ◽  
Xueyan Feng ◽  
Ka Lung Chan ◽  
Linxin Li ◽  
...  
Keyword(s):  
Risk Factors ◽  
Ct Angiography ◽  
Interobserver Agreement ◽  
Arterial Stenosis ◽  
Minor Stroke ◽  
Intracranial Arterial Stenosis ◽  
Stroke Patients ◽  
Stroke Registry ◽  
The Difference ◽  
Ischemic Attack

Background: Despite numerous reports indicating ethnic difference in intracranial arterial stenosis (ICAS) between Caucasians and Asians, there has been no direct comparison in disease burden and clinical correlates of ICAS in stroke patients in the two populations with the same criteria to define ICAS. Methods: Acute minor stroke or transient ischemic attack patients who received cerebral MR/CT angiography exam in two cohorts were analyzed: Oxford Vascular Study (OXVASC, 2011-2018) with predominantly Caucasians, and the Chinese University of Hong Kong (CUHK) stroke registry (2011-2015) with predominantly Chinese. ICAS was defined as ≥50% stenosis in any major intracranial artery in MR/CT angiography. Interobserver agreement between 2 investigators for presence of ICAS was assessed in 50 cases with Cohen’s kappa. We compared the burden and risk factors of ICAS in the two cohorts. Results: Overall, 1,287 patients from OXVASC (mean age 69 years) and 640 from the CUHK cohort (mean age 66 years) were analyzed. Interobserver agreement for presence of ICAS was good (kappa=0.82). Prevalence of ICAS was significantly higher in Chinese than in Caucasians: 43.6% in the CUHK cohort versus 20.0% in OXVASC (crude OR 3.10; age-adjusted OR 3.81, 95% CI 3.06-4.75; p<0.001). Mean ages of patients with ICAS in the two cohorts were 75 and 68 years, respectively. The difference between Caucasians and Chinese in ICAS prevalence was smaller in those aged ≥70 years (28.1% versus 51.9%) than those <70 years (9.8% versus 38.0%) (Figure). ICAS shared similar risk factors in the two cohorts, including older age, and history of hypertension and diabetes. Conclusions: Chinese are more susceptible to ICAS, with an earlier onset age than Caucasians, but the ICAS burden in Caucasians was higher than previously estimated, especially in older patients.

scholarly journals Syntax-Sensitive Regions of the Posterior Inferior Frontal Gyrus and the Posterior Temporal Lobe Are Differentially Recruited by Production and Perception

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
William Matchin ◽  
Emily Wood
Keyword(s):  
Temporal Lobe ◽  
Inferior Frontal Gyrus ◽  
Regions Of Interest ◽  
Syntactic Processing ◽  
Activation Patterns ◽  
Fmri Study ◽  
Left Posterior ◽  
Lesion Symptom Mapping

Abstract Matchin and Hickok (2020) proposed that the left posterior inferior frontal gyrus (PIFG) and the left posterior temporal lobe (PTL) both play a role in syntactic processing, broadly construed, attributing distinct functions to these regions with respect to production and perception. Consistent with this hypothesis, functional dissociations between these regions have been demonstrated with respect to lesion–symptom mapping in aphasia. However, neuroimaging studies of syntactic comprehension typically show similar activations in these regions. In order to identify whether these regions show distinct activation patterns with respect to syntactic perception and production, we performed an fMRI study contrasting the subvocal articulation and perception of structured jabberwocky phrases (syntactic), sequences of real words (lexical), and sequences of pseudowords (phonological). We defined two sets of language-selective regions of interest (ROIs) in individual subjects for the PIFG and the PTL using the contrasts [syntactic &gt; lexical] and [syntactic &gt; phonological]. We found robust significant interactions of comprehension and production between these 2 regions at the syntactic level, for both sets of language-selective ROIs. This suggests a core difference in the function of these regions with respect to production and perception, consistent with the lesion literature.

Distinct activation patterns for accurate vs. inaccurate naming of actions and objects: An fMRI study with stroke patients with chronic aphasia

2007 ◽  
Vol 103 (1-2) ◽  
pp. 150-151 ◽  
Author(s):  
W.A. Postman-Caucheteux ◽  
S. Hoffman ◽  
D. Picchioni ◽  
J. McArdle ◽  
R. Birn ◽  
...  
Keyword(s):  
Stroke Patients ◽  
Activation Patterns ◽  
Fmri Study ◽  
Chronic Aphasia

scholarly journals Alpha and beta rhythms differentially support the effect of symbols on visual object recognition

2021 ◽  
Author(s):  
Piermatteo Morucci ◽  
Francesco Giannelli ◽  
Craig Richter ◽  
Nicola Molinaro
Keyword(s):  
Object Recognition ◽  
Reaction Times ◽  
Matching Task ◽  
Visual Object ◽  
Visual Object Recognition ◽  
Natural Sounds ◽  
Beta Oscillations ◽  
Visual Processes ◽  
Spoken Words ◽  
Beta Rhythms

Hearing spoken words can enhance visual object recognition, detection and discrimination. Yet, the mechanism underlying this facilitation is incompletely understood. On one account, words would not bias visual processes at early levels, but rather interact at later decision-making stages. More recent proposals posit that words can alter visual processes at early stages by activating category-specific priors in sensory regions. A prediction of this account is that top-down priors evoke changes in occipital areas before the presentation of visual stimuli. Here, we tested the hypothesis that neural oscillations can serve as a mechanism to activate language-mediated visual priors. Participants performed a cue-picture matching task where cues were either spoken words, in their native or second language, or natural sounds, while EEG and reaction times were recorded. Behaviorally, we replicated the previously reported label-advantage effect, with images cued by words being recognized faster than those cued by natural sounds. A time-frequency analysis of cue-target intervals revealed that this label-advantage was associated with enhanced power in posterior alpha (9-11 Hz) and beta oscillations (17-19 Hz), both of which were larger when the image was preceded by a word compared to a natural sound. Prestimulus alpha and beta rhythms were correlated with reaction time performance, yet they appeared to operate in different ways. Reaction times were faster when alpha power increased, but slowed down with enhancement of beta oscillations. These results suggest that alpha and beta rhythms work in tandem to support language-mediated visual object recognition, while showing an inverse relationship to behavioral performance.

scholarly journals Mechanical Thrombectomy for Minor Stroke Patients (NIHSS <6) With Large Vessel Occlusion

2018 ◽  
Vol 24 (2) ◽  
pp. 67-70
Author(s):  
Çetin Kürşad Akpınar ◽  
Erdem Gürkaş ◽  
Emrah Aytaç ◽  
Murat Çalık
Keyword(s):  
Mechanical Thrombectomy ◽  
Large Vessel ◽  
Minor Stroke ◽  
Large Vessel Occlusion ◽  
Stroke Patients ◽  
Vessel Occlusion

scholarly journals Covert Visual Attention Modulates Face-Specific Activity in the Human Fusiform Gyrus: fMRI Study

1998 ◽  
Vol 79 (3) ◽  
pp. 1574-1578 ◽  
Author(s):  
Ewa Wojciulik ◽  
Nancy Kanwisher ◽  
Jon Driver
Keyword(s):  
Visual Attention ◽  
Specific Activity ◽  
Region Of Interest ◽  
Fusiform Gyrus ◽  
Covert Attention ◽  
Matching Task ◽  
Voluntary Attention ◽  
Retinal Stimulation ◽  
Covert Visual Attention ◽  
Fmri Study

Wojciulik, Ewa, Nancy Kanwisher, and Jon Driver. Covert visual attention modulates face-specific activity in the human fusiform gyrus: an fMRI study. J. Neurophysiol. 79: 1574–1578, 1998. Several lines of evidence demonstrate that faces undergo specialized processing within the primate visual system. It has been claimed that dedicated modules for such biologically significant stimuli operate in a mandatory fashion whenever their triggering input is presented. However, the possible role of covert attention to the activating stimulus has never been examined for such cases. We used functional magnetic resonance imaging to test whether face-specific activity in the human fusiform face area (FFA) is modulated by covert attention. The FFA was first identified individually in each subject as the ventral occipitotemporal region that responded more strongly to visually presented faces than to other visual objects under passive central viewing. This then served as the region of interest within which attentional modulation was tested independently, using active tasks and a very different stimulus set. Subjects viewed brief displays each comprising two peripheral faces and two peripheral houses (all presented simultaneously). They performed a matching task on either the two faces or the two houses, while maintaining central fixation to equate retinal stimulation across tasks. Signal intensity was reliably stronger during face-matching than house matching in both right- and left-hemisphere predefined FFAs. These results show that face-specific fusiform activity is reduced when stimuli appear outside (vs. inside) the focus of attention. Despite the modular nature of the FFA (i.e., its functional specificity and anatomic localization), face processing in this region nonetheless depends on voluntary attention.

Abstract 41: Prognostic Value of Perfusion MRI in Patients with Transient Ischemic Attack or Minor Stroke

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Joon Hwa Lee ◽  
Hyunjin Jo ◽  
Jihoon Cha ◽  
Woo-Keun Seo ◽  
Oh Young Bang ◽  
...  
Keyword(s):  
Cardiovascular Event ◽  
Transient Ischemic Attack ◽  
Recurrent Stroke ◽  
Perfusion Mri ◽  
Minor Stroke ◽  
Secondary Outcome ◽  
Stroke Recurrence ◽  
Composite Outcome ◽  
Stroke Patients ◽  
Ischemic Attack

Background and purpose: We aimed to investigate the role of perfusion MRI parameters (TTP: time to peak, CBF: cerebral blood flow, CBV: cerebral blood volume) as a prognostic factor for the risk of stroke recurrence or cardiovascular outcome in patients with transient ischemic attack (TIA) or minor stroke. Methods: We retrospectively reviewed TIA or minor stroke patients who underwent our stroke MRI protocol (DWI, perfusion MRI, and MRA) in a consecutively collected stroke registry. Primary outcome was nonfatal stroke recurrence and secondary outcome was cardiovascular composite outcome. Multivariate analysis was used to examine the association of perfusion MRI parameters and angiographic findings with the risk of stroke recurrence and cardiovascular event. Results: Of the 326 patients who met inclusion criteria, we identified 15(4.6%) nonfatal strokes and 25(7.7%) cardiovascular composite events during the first 1 year after the index TIA or minor stroke. The presence of regional delayed perfusion on TTP maps (p=0.002) and regional hyperperfusion on CBV maps (p<0.001) were associated with recurrent stroke. In MRA images, concomitant stenosis of the intracranial arteries and/or extracranial carotid arteries was associated with cardiovascular events (p=0.009). Using multivariate cox proportional hazard analysis, presence of regional hyperperfusion on CBV remained an independent predictor of recurrent stroke (HR 10.82, 95% CI 4.19-38.67, p<0.001) and cardiovascular event (HR 6.30, 95% CI 2.67-18.25, p<0.001). The AUC of the CBV maps was also greater than other parameters for the prediction of stroke recurrence (AUC=0.701, 95% CI 0.54-0.86) and cardiovascular composite outcome (AUC=0.628, 95% CI 0.50-0.76). Conclusions: Increased CBV on perfusion MRI, representing the hemodynamic status of postischemic hyperperfusion, could be more useful than other perfusion parameters in predicting poor prognosis of TIA or minor stroke patients.

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