Objectives
Positive visual phenomena, although reported in lesions of visual cortex, are often overlooked in patients with acute neurological conditions. Yet, their occurrence without structural ...abnormalities or other underlying neurological disorders represents a unique observation. This report aims to raise awareness of these phenomena, their implications for understanding visual consciousness and to propose a practical, structured algorithm for the clinical assessment of visual hallucinations related to neurological conditions.
Methods
We describe the clinical presentation and imaging findings in two patients with isolated visual hallucinosis secondary to transitory hypoperfusion.
Results
One patient presented with subocclusion of the right posterior cerebral artery and the other with multifocal arterial abnormalities suggestive of reversible cerebral vasoconstriction syndrome (RCVS). Both presented isolated visual hallucinations and hypoperfusion of the right mesial occipito-temporal cortex. Hallucinated images exhibited peculiarities of certain attributes that were recognized only through guided perceptual analysis performed during their occurrence.
Discussion
Dysfunctions in the visual and attentional networks due to the uneven impact of hypoperfusion on the regions of the mesial occipito-temporal cortex likely contributed to the occurrence of visual hallucinations. The initial impaired awareness of certain image attributes obscured an altered, non-realistic rendering of the hallucinated images. Enhancement of awareness through clinical guidance indicates improved attentional deployment, modulation of visual information processing and hallucination–background integration. These features of the hallucinatory phenomena highlight the critical role of semiological analysis during their occurrence and question the validity of post hoc inquiries.
The optimal methods for predicting early infarct growth rate (EIGR) in acute ischemic stroke with a large vessel occlusion (LVO) have not been established. We aimed to study the factors associated ...with EIGR, with a focus on the collateral circulation as assessed by the hypoperfusion intensity ratio (HIR) on perfusion imaging, and determine whether the associations found are consistent across imaging modalities.
Retrospective multicenter international study including patients with anterior circulation LVO-related acute stroke with witnessed stroke onset and baseline perfusion imaging (MRI or CT) performed within 24 hours from symptom onset. To avoid selection bias, patients were selected from (1) the prospective registries of 4 comprehensive stroke centers with systematic use of perfusion imaging and including both thrombectomy-treated and untreated patients and (2) 1 prospective thrombectomy study where perfusion imaging was acquired per protocol, but treatment decisions were made blinded to the results. EIGR was defined as infarct volume on baseline imaging divided by onset-to-imaging time and fast progressors as EIGR ≥10 mL/h. The HIR, defined as the proportion of time-to-maximum (Tmax) >6 second with Tmax >10 second volume, was measured on perfusion imaging using RAPID software. The factors independently associated with fast progression were studied using multivariable logistic regression models, with separate analyses for CT- and MRI-assessed patients.
Overall, 1,127 patients were included (CT, n = 471; MRI, n = 656). Median age was 74 years (interquartile range IQR 62-83), 52% were male, median NIH Stroke Scale was 16 (IQR 9-21), median HIR was 0.42 (IQR 0.26-0.58), and 415 (37%) were fast progressors. The HIR was the primary factor associated with fast progression, with very similar results across imaging modalities: The proportion of fast progressors was 4% in the first HIR quartile (i.e., excellent collaterals), ∼15% in the second, ∼50% in the third, and ∼77% in the fourth (
< 0.001 for each imaging modality). Fast progression was independently associated with poor 3-month functional outcome in both the CT and MRI cohorts (
< 0.001 and
= 0.030, respectively).
The HIR is the primary factor associated with fast infarct progression, regardless of imaging modality. These results have implication for neuroprotection trial design, as well as informing triage decisions at primary stroke centers.
Circadian variability has been implicated in timing of stroke onset, yet the full impact of underlying biological rhythms on acute stroke perfusion patterns is not known. We aimed to describe the ...relationship between time of stroke onset and perfusion profiles in patients with large vessel occlusion (LVO).
A retrospective observational study was conducted using prospective registries of four stroke centers across North America and Europe with systematic use of perfusion imaging in clinical care. Included patients had stroke due to ICA, M1 or M2 occlusion and baseline perfusion imaging performed within 24h from last-seen-well (LSW). Stroke onset was divided into eight hour intervals: (1) Night: 23:00-6:59, (2) Day: 7:00-14:59, (3) Evening: 15:00-22:59. Core volume was estimated on CT perfusion (rCBF <30%) or DWI-MRI (ADC <620) and the collateral circulation was estimated with the Hypoperfusion Intensity Ratio (HIR = Tmax>10s/Tmax>6s). Non-parametric testing was conducted using SPSS to account for the non-normalized dependent variables.
A total of 1506 cases were included (median age 74.9 years, IQR 63.0-84.0). Median NIHSS, core volumes, and HIR were 14.0 (IQR 8.0-20.0), 13.0mL (IQR 0.0-42.0), and 0.4 (IQR 0.2-0.6) respectively. Most strokes occurred during the Day (n = 666, 44.2%), compared to Night (n = 360, 23.9%), and Evening (n = 480, 31.9%). HIR was highest, indicating worse collaterals, in the Evening compared to the other timepoints (p = 0.006). Controlling for age and time to imaging, Evening strokes had significantly higher HIR compared to Day (p = 0.013).
Our retrospective analysis suggests that HIR is significantly higher in the evening, indicating poorer collateral activation which may lead to larger core volumes in these patients.
Components critical to cerebral perfusion have been noted to oscillate over a 24-h cycle. We previously reported that ischemic core volume has a diurnal relationship with stroke onset time when ...examined as dichotomized epochs (i.e. Day, Evening, Night) in a cohort of over 1,500 large vessel occlusion (LVO) patients. In this follow-up analysis, our goal was to explore if there is a sinusoidal relationship between ischemic core, collateral status (as measured by HIR), and stroke onset time.
We retrospectively examined collection of LVO patients with baseline perfusion imaging performed within 24 h of stroke onset from four international comprehensive stroke centers. Both ischemic core volume and HIR, were utilized as the primary radiographic parameters. To evaluate for differences in these parameters over a continuous 24-h cycle, we conducted a sinusoidal regression analysis after linearly regressing out the confounders age and time to imaging.
A total of 1506 LVO cases were included, with a median ischemic core volume of 13.0 cc (IQR: 0.0-42.0) and median HIR of 0.4 (IQR: 0.2-0.6). Ischemic core volume varied by stroke onset time in the unadjusted (p = 0.001) and adjusted (p = 0.003) sinusoidal regression analysis with a peak in core volume around 7:45PM. HIR similarly varied by stroke onset time in the unadjusted (p = 0.004) and adjusted (p = 0.002) models with a peak in HIR values at around 8:18PM.
The results suggest that critical factors to the development of the ischemic core vary by stroke onset time and peak around 8PM. When placed in the context of prior studies, strongly suggest a diurnal component to the development of the ischemic core.
Botulinum toxin type A is one of the most useful treatments of sialorrhea in neurological disorders. Evidence for the use of incobotulinumtoxin A (inco-A) in the treatment of sialorrhea is limited. ...Thirty-six patients with sialorrhea were treated with infiltrations of inco-A into both parotid glands. The severity of sialorrhea was evaluated by the Drooling Severity Scale (DSS), and the Drooling Frequency Scale (DFS). Patients' perceptions of clinical benefit were recorded via the Patient Global Impression of Improvement (PGI-I) scale. Following treatment, there was a significant difference in both the DFS and the DSS (
< 0.001). Clinical benefits on the basis of the PGI-I were present in up to 90% of patients.
The majority of small vessel diseases is related to vascular risk factors or sporadic amyloid angiopathy, but a minority is caused by genetic, immune, or infectious diseases. In this article, we ...propose a pragmatic approach for the diagnosis and treatment of rare causes of cerebral small vessel disease.
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