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IntroductionChatGPT, a novel AI-based chatbot, sparked a lot of interest in the scientific community. Complex central CNS tumour cases require multidisciplinary expert recommendations that incorporate multimodal disease information. Thus, the potential of ChatGPT to integrate comprehensive treatment information may be of tremendous benefit for CNS tumour decision-making. We evaluated the ChatGPT recommendations for glioma management by a panel of CNS tumour experts.MethodsWe randomly selected 10 patients with primary CNS gliomas discussed at our institution’s Tumour Board. Patients’ clinical status, surgical, imaging, and immuno-pathology-related information was provided to ChatGPT and seven CNS tumour experts. The chatbot was asked to give the most likely diagnosis, the adjuvant treatment choice, and the regimen while considering the patient’s functional status. The experts rated the AI-based recommendations from 0 (complete disagreement) to 10 (complete agreement). An intraclass correlation agreement (ICC) was used to measure the inter-rater agreement.ResultsEight patients (80%) met the criteria for glioblastoma and two (20%) were low-grade gliomas. The experts rated the quality of ChatGPT recommendations as poor for diagnosis (median 3, IQR 1-7.8, ICC 0.9, 95% CI 0.7-1.0), good for treatment recommendation (7, IQR 6-8, ICC 0.8, 95% CI 0.4-0.9), good for therapy regimen (7, IQR 4-8, ICC 0.8, 95% CI 0.5-0.9), moderate for functional status consideration (6, IQR 1-7, ICC 0.7, 95% CI 0.3-0.9), and moderate for overall agreement with the recommendations (5, IQR 3-7, ICC 0.7, 95% CI 0.3-0.9). No difference were observed between the glioblastomas and low-grade glioma ratings.ConclusionsChatGPT performed poorly in classifying glioma types but was good for adjuvant treatment recommendations as evaluated by CNS Tumour Board experts. Even though the ChatGPT lacks the precision to replace expert opinion, it may become a promising tool to supplement experts, especially in low-resource settings.

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.

Introduction: Endovascular treatment (EVT) is the therapy of choice, in patients with unknown stroke onset (unwitnessed and wake-up strokes) and large vessel occlusion (LVO) with a favorable perfusion pattern. Whether bridging therapy (intravenous thrombolysis (IVT) and EVT) is superior to EVT alone remains unknown. Material and Methods: We retrospectively included all patients admitted to the Geneva University Hospital from 01.2016 to 06.2020 with i) stroke of unknown onset, due to ii) anterior circulation occlusion, with iii) favorable CT perfusion pattern based on the DEFUSE criteria (ischemic core volume< 70ml; mismatch ratio >= 1.8 and mismatch volume >= 15ml), and iv) treated < 4.5 hours after symptom recognition. As a standard of care, the patients fulfilling these inclusion criteria were treated with EVT and IVT or EVT alone when IVT was contraindicated. Outcome measures were any intracerebral bleeding (symptomatic or asymptomatic), mortality and favorable outcome (mRS 0-1) at three months. Results: 32 patients were included (17 treated with EVT alone and 15 with EVT and IVT). Mean age was 69±18 yo. Median NIHSS was 16 (IQR 12-20) and median time from symptom recognition to treatment was 184 (146-226) minutes. Median hypoperfused tissue volume (Tmax > 6s) was 119 ml (80-151) and infarcted core (CBF ratio Conclusion: These results suggest that IVT before EVT is a safe therapeutic option in patients with unknown stroke onset selected on perfusion imaging and treated

Objective To compare the diagnostic performance of an artificial intelligence deep learning system with that of expert neuro-ophthalmologists in classifying optic disc appearance. Methods The deep learning system was previously trained and validated on 14,341 ocular fundus photographs from 19 international centers. The performance of the system was evaluated on 800 new fundus photographs (400 normal optic discs, 201 papilledema [disc edema from elevated intracranial pressure], 199 other optic disc abnormalities) and compared with that of 2 expert neuro-ophthalmologists who independently reviewed the same randomly presented images without clinical information. Area under the receiver operating characteristic curve, accuracy, sensitivity, and specificity were calculated. Results The system correctly classified 678 of 800 (84.7%) photographs, compared with 675 of 800 (84.4%) for Expert 1 and 641 of 800 (80.1%) for Expert 2. The system yielded areas under the receiver operating characteristic curve of 0.97 (95% confidence interval [CI] = 0.96-0.98), 0.96 (95% CI = 0.94-0.97), and 0.89 (95% CI = 0.87-0.92) for the detection of normal discs, papilledema, and other disc abnormalities, respectively. The accuracy, sensitivity, and specificity of the system's classification of optic discs were similar to or better than the 2 experts. Intergrader agreement at the eye level was 0.71 (95% CI = 0.67-0.76) between Expert 1 and Expert 2, 0.72 (95% CI = 0.68-0.76) between the system and Expert 1, and 0.65 (95% CI = 0.61-0.70) between the system and Expert 2. Interpretation The performance of this deep learning system at classifying optic disc abnormalities was at least as good as 2 expert neuro-ophthalmologists. Future prospective studies are needed to validate this system as a diagnostic aid in relevant clinical settings. ANN NEUROL 2020;88:785-795.

Disorders that specifically affect central and peripheral vision constitute invaluable models to study how the human brain adapts to visual deafferentation. We explored cortical changes after the loss of central or peripheral vision. Cortical thickness (CoTks) and resting-state cortical entropy (rs-CoEn), as a surrogate for neural and synaptic complexity, were extracted in 12 Stargardt macular dystrophy, 12 retinitis pigmentosa (tunnel vision stage), and 14 normally sighted subjects. When compared to controls, both groups with visual loss exhibited decreased CoTks in dorsal area V3d. Peripheral visual field loss also showed a specific CoTks decrease in early visual cortex and ventral area V4, while central visual field loss in dorsal area V3A. Only central visual field loss exhibited increased CoEn in LO-2 area and FG1. Current results revealed biomarkers of brain plasticity within the dorsal and the ventral visual streams following central and peripheral visual field defects. Electronic supplementary material The online version of this article (10.1007/s00429-018-1700-7) contains supplementary material, which is available to authorized users.

Chordoid glioma of the third ventricle (CGTV) is a rare, slow-growing, World Health Organization Grade II glial tumor, with stereotyped localization in the anterior third ventricle. Despite being considered a noninvasive tumor, CGTV is usually associated with a poor clinical outcome due to its close proximity to important cerebral structures, such as the hypothalamus and visual pathways. Our patient with CGTV experienced visual involvement, but after subtotal surgical resection showed no evidence of progression at 5-year follow-up.

BACKGROUND: Nonophthalmologist physicians do not confidently perform direct ophthalmos-copy. The use of artificial intelligence to detect papilledema and other optic-disk abnormalities from fundus photographs has not been well studied METHODS: We trained, validated, and externally tested a deep-learning system to classify optic disks as being normal or having papilledema or other abnormalities from 15,846 retrospectively collected ocular fundus photographs that had been obtained with pharmacologic pupillary dilation and various digital cameras in persons from multiple ethnic populations. Of these photographs, 14,341 from 19 sites in 11 coun-tries were used for training and validation, and 1505 photographs from 5 other sites were used for external testing. Performance at classifying the optic-disk ap-pearance was evaluated by calculating the area under the receiver-operating-characteristic curve (AUC), sensitivity, and specificity, as compared with a reference standard of clinical diagnoses by neuro-ophthalmologists RESULTS: The training and validation data sets from 6779 patients included 14,341 photo-graphs: 9156 of normal disks, 2148 of disks with papilledema, and 3037 of disks with other abnormalities. The percentage classified as being normal ranged across sites from 9.8 to 100%; the percentage classified as having papilledema ranged across sites from zero to 59.5%. In the validation set, the system discriminated disks with papilledema from normal disks and disks with nonpapilledema abnor-malities with an AUC of 0.99 (95% confidence interval [CI], 0.98 to 0.99) and normal from abnormal disks with an AUC of 0.99 (95% CI, 0.99 to 0.99). In the external-testing data set of 1505 photographs, the system had an AUC for the detection of papilledema of 0.96 (95% CI, 0.95 to 0.97), a sensitivity of 96.4% (95% CI, 93.9 to 98.3), and a specificity of 84.7% (95% CI, 82.3 to 87.1).CONCLUSIONSA deep-learning system using fundus photographs with pharmacologically dilated pupils differentiated among optic disks with papilledema, normal disks, and disks with nonpapilledema abnormalities. (Funded by the Singapore National Medical Research Council and the SingHealth Duke–NUS Ophthalmology and Visual Sci-ences Academic Clinical Program.)

BACKGROUND AND PURPOSE The impact of intravenous recombinant tissue plasminogen activator (IV-rtPA) in patients with acute ischaemic stroke (AIS) but no arterial occlusion is currently a matter of debate. This study aimed to assess functional outcome of such patients with respect to IV-rtPA use. METHODS A retrospective case-control analysis was performed comparing the outcome of AIS patients without arterial occlusion with or without IV-rtPA use. Patients were selected from prospective consecutive observational registries of five European university hospitals. The primary study outcome was excellent outcome at 3 months after stroke, as defined by a modified Rankin Scale (mRS) 0-1. RESULTS A total of 488 patients without arterial occlusion documented by angiography were included in the present study; 300 received IV-rtPA and 188 did not. No between-group difference was found for excellent outcome before and after adjustment for baseline characteristics (adjusted odds ratio for no IV-rtPA use 0.79, 95% confidence interval 0.51-1.24, P = 0.31). Similar results were found for favourable outcome (defined as a 90-day mRS of 0-2) whereas a higher rate of early neurological improvement was found in IV-rtPA-treated patients (adjusted odds ratio 1.99; 95% confidence interval 1.29-3.07, P = 0.002). Sensitivity analyses yielded similar results. CONCLUSIONS Our study suggests that AIS patients without visible arterial occlusion treated with IV-rtPA may have no better outcome at 3 months than those untreated. However, only a randomized controlled trial would provide a definitive answer about the impact of rtPA in acute stroke patients without occlusion. Until then, these patients should be treated by rtPA as recommended.

Behavioral alterations emerging after central or peripheral vision loss suggest that cerebral reorganization occurs for both the afferented and deafferented early visual cortex (EVC). We explored the functional reorganization of the central and peripheral EVC following visual field defects specifically affecting central or peripheral vision. Compared to normally sighted, afferented central and peripheral EVC enhance their functional connectivity with areas involved in visual processing, whereas deafferented central and peripheral EVC increase their functional connectivity with more remote regions. The connectivity pattern of afferented EVC suggests adaptive changes that might enhance the visual processing capacity whereas the connectivity pattern of deafferented EVC may reflect the involvement of these regions in high-order mechanisms. Characterizing and understanding the plastic changes induced by these visual defects is essential for any attempt to develop efficient rehabilitation strategies.

International audience; In the congenitally blind, language processing involves visual areas. In the case of normal visual development however, it remains unclear whether later visual loss induces interactions between the language and visual areas. This study compared the resting-state functional connectivity (FC) of retinotopic and language areas in two unique groups of late visually deprived subjects: (1) blind individuals suffering from retinitis pigmentosa (RP), (2) RP subjects without a visual periphery but with preserved central “tunnel vision”, both of whom were contrasted with sighted controls. The results showed increased FC between Broca's area and the visually deprived areas in the peripheral V1 for individuals with tunnel vision, and both the peripheral and central V1 for blind individuals. These findings suggest that FC can develop in the adult brain between the visual and language systems in the completely and partially blind. These changes start in the deprived areas and increase in size (involving both foveal and peripheral V1) and strength (from negative to positive FC) as the disease and sensory deprivation progress. These observations support the claim that functional connectivity between remote systems that perform completely different tasks can change in the adult brain in cases of total and even partial visual deprivation.

Rationale Immunoglobulin G4-related disease (IgG4-RD) is an inflammatory condition of unknown cause. Cancer might be related to the development of certain IgG4-RD but to date, little literature documents it. Patient concerns A 78-year old man presented with unilateral proptosis responsive to steroids, initially attributed to nonspecific orbital inflammation. Diagnosis Right hemicolectomy was performed because of a suspicious lesion which turned out to be tubulovillous adenoma on histological analysis. Eight months after the surgery, a mass infiltrating the mesentery was found and biopsy revealed IgG4-RD. Interventions Both the orbital inflammation and abdominal mass infiltrating the mesentery were responsive to steroids and rituximab administered to treat IgG4-RD. Outcomes In the course of IgG4-RD, the patient developed bilateral optic perineuritis, causing bilateral visual loss. Colon cancer with synchronous multiple liver metastases was found 1 year after rituximab treatment. Lessons This case raises the possibility of IgG4-RD being a paraneoplastic syndrome in some patients. Cancer screening should probably be performed in some elderly patients diagnosed with IgG4-RD.

Purpose of review Synesthesia is an extraordinary perceptual phenomenon, in which individuals experience unusual percepts elicited by the activation of an unrelated sensory modality or by a cognitive process. Emotional reactions are commonly associated. The condition prompted philosophical debates on the nature of perception and impacted the course of art history. It recently generated a considerable interest among neuroscientists, but its clinical significance apparently remains underevaluated. This review focuses on the recent studies regarding variants of color synesthesia, the commonest form of the condition. Recent findings Synesthesia is commonly classified as developmental and acquired. Developmental forms predispose to changes in primary sensory processing and cognitive functions, usually with better performances in certain aspects and worse in others, and to heightened creativity. Acquired forms of synesthesia commonly arise from drug ingestion or neurological disorders, including thalamic lesions and sensory deprivation (e.g., blindness). Cerebral exploration using structural and functional imaging has demonstrated distinct patterns in cortical activation and brain connectivity for controls and synesthetes. Artworks of affected painters are most illustrative of the nature of synesthetic experiences. Summary Results of the recent investigations on synesthesia offered a remarkable insight into the mechanisms of perception, emotion and consciousness, and deserve attention both from neuroscientists and from clinicians.

Purpose With a retinal prosthesis connected to a head-mounted camera (camera-connected prosthesis [CC-P]), subjects explore the visual environment through head-scanning movements. As eye and camera misalignment might alter the spatial localization of images generated by the device, we investigated if such misalignment occurs in blind subjects wearing a CC-P and whether it impacts spatial localization, even years after the implantation. Methods We studied three subjects blinded by retinitis pigmentosa, fitted with a CC-P (Argus II) 4 years earlier. Eye/head movements were video recorded as subjects tried to localize a visual target. Pointing coordinates were collected as subjects were requested to orient their gaze toward predetermined directions, and to point their finger to the corresponding perceived spot locations on a touch screen. Finally, subjects were asked to give a history of their everyday behavior while performing visually controlled grasping tasks. Results Misaligned head and gaze directions occurred in all subjects during free visual search. Pointing coordinates were collected in two subjects and showed that median pointing directions shifted toward gaze direction. Reportedly all subjects were unable to accurately determine their eye position, and they developed adapted strategies to perform visually directed movements. Conclusions Eye position affected perceptual localization of images generated by the Argus II prosthesis, and consequently visuomotor coordination, even 4 years following implantation. Affected individuals developed strategies for visually guided movements to attenuate the impact of eye and head misalignment. Our observations provide indications for rehabilitation procedures and for the design of upcoming retinal prostheses. (ClinicalTrials.gov number, NCT00407602.).

Radiation-induced optic neuropathy (RION) is a late complication of radiotherapy, resulting in severe visual loss.1 We report a RION case following radiation therapy delivered at a dose widely considered as innocuous, occurring on a background of previous isolated optic neuritis. Increased brain sensitivity to radiation has been observed in patients with multiple sclerosis (MS),2–4 but we are not aware of previously reported cases solely involving the optic nerves (ONs). This aspect deserves consideration when defining therapeutic strategies.