Search Results (14)

Introduction: This study was conducted to determine whether specific emergency physician (EP) diagnoses and/or neurological signs/symptoms upon admission to the Emergency Department (ED) were associated with normal/non-informative emergency electroencephalogram (emEEG). Methods: Data from consecutive patients admitted to the ED of our tertiary hospital over a two-year period (1 January 2023–31 December 2024) were analyzed retrospectively. We evaluated the correlation between normal/non-specific emEEGs and EP admission diagnoses and neurological signs/symptoms on admission. Epileptic discharges and sharp waves with triphasic morphology were considered specific patterns. Results: A total of 2008 patients underwent emEEG recording during the study period. EmEEGs were considered non-informative in 100% of global amnesia diagnoses, 100% of cases of mild head trauma, 100% of cases of migraine with aura, 98.3% of transient ischemic attacks (TIAs), 95.6% of transient losses of consciousness (TLCs) when seizure was not the primary suspected diagnosis, and in 92.7% of falls of unknown dynamics. Epileptic patterns were detected in 4% of patients presenting with TLC and in 2.4% of those with falls of unknown dynamics, with approximately half of these patients having a pre-existing diagnosis of epilepsy. Triphasic waves were detected in 4.9% patients with falls of unknown dynamics, in 1.7% with TIA, and in 0.4% with TLC. All of these patients had fever/sepsis or metabolic/electrolyte disorders. Overall, across all clinical scenarios, emEEGs were considered non-informative in 385 (19.1%) tested patients. Conclusions: emEEGs are almost non-informative in the diagnostic pathway for patients with global amnesia, mild head trauma, and migraine with aura, and in patients with TIA, TLC, or falls of unknown dynamics. EPs can safely consider avoiding emEEGs in the absence of previous epilepsy diagnosis, fever/sepsis, metabolic/electrolyte disturbances, or drug abuse. Full article

We aimed to determine whether transient global amnesia (TGA) is associated with alterations in central nervous system (CNS) injury biomarkers—serum neurofilament light chain (sNfL) and serum glial fibrillary acidic protein (sGFAP). In a prospective cohort of TGA patients, blood samples were obtained within 24–48 h of TGA onset (t0) and 6 weeks thereafter (t1). We assessed sNfL and sGFAP levels using the highly sensitive single-molecule array assay and calculated Z-scores adjusted for age, gender, and body mass index (BMI). Demographics, electroencephalography (EEG), and cerebral magnetic resonance imaging (cMRI) findings were also collected. A total of 20 patients were included (median age: 66 years, 70% women). No significant changes in sNfL or sGFAP levels associated with TGA at t0 and t1 were observed. Median sNfL Z-scores were 0.45 (interquartile range [IQR] −0.09, 1.19) at t0 and 0.60 (IQR −0.61, 1.19) at t1. Median sGFAP Z-scores were 0.27 (IQR −0.45, 0.76) at t0 and 0.44 (IQR −0.27, 0.75) at t1. Similarly, in the subgroup of patients with diffusion-weighted imaging (DWI)-positive hippocampal lesions (n = 5/20[25%]), no elevations in blood biomarkers were detected. Our pilot study on neurological blood biomarkers supports the benign nature of TGA, indicating that no CNS tissue damage occurs. Full article

The differential diagnosis of acute-onset amnesia includes transient global amnesia (TGA), transient epileptic amnesia (TEA), and functional (or psychogenic) amnesia. The most common of these, TGA, is a rare but well-described condition characterised by a self-limited episode of dense anterograde amnesia with variable retrograde amnesia. Although the clinical phenomenology of TGA is well described, its pathogenesis is not currently understood, thus preventing the development of evidence-based therapeutic recommendations. Here, TGA, TEA, and functional amnesia are considered in light of the historical engram conception of memory, now informed by recent experimental research, as disturbances in distributed ensembles of engram neurones active during memory formation and recall. This analysis affords therapeutic implications for these conditions, should interventions to reactivate latent or silent engrams become available. Full article

Transient global amnesia, both persistent and transient, is a very common neuropsychiatric syndrome. Among animal models for amnesia and testing new drugs, the scopolamine test is the most widely used for transient global amnesia (TGA). This study examined the scopolamine-induced deficits in working memory, discriminative memory, anxiety, and motor activity in the presence of intranasal PEA-OXA, a dual antagonist of presynaptic α2 and H3 receptors. Male C57BL/6 mice were treated with intraperitoneal scopolamine (1 mg/kg) with or without pre-treatment (15 min) or post-treatment (15 min) with intranasal PEA-OXA (10 mg/kg). It was seen that scopolamine induced deficits of discriminative and spatial memory and motor deficit. These changes were associated with a loss of synaptic plasticity in the hippocampal dentate gyrus: impaired LTP after lateral entorhinal cortex/perforant pathway tetanization. Furthermore, hippocampal Ach levels were increased while ChA-T expression was reduced following scopolamine administration. PEA-OXA either prevented or restored the scopolamine-induced cognitive deficits (discriminative and spatial memory). However, the same treatment did not affect the altered motor activity or anxiety-like behavior induced by scopolamine. Consistently, electrophysiological analysis showed LTP recovery in the DG of the hippocampus, while the Ach level and ChoA-T were normalized. This study confirms the neuroprotective and pro-cognitive activity of PEA-OXA (probably through an increase in the extracellular levels of biogenic amines) in improving transient memory disorders for which the available pharmacological tools are obsolete or inadequate and not directed on specific pathophysiological targets. Full article

Transient epileptic amnesia (TEA) is a rare cause of acute amnestic syndromes (AAS), often misdiagnosed as transient global amnesia (TGA). We proposed a scoring system—the EPIlepsy AMNEsia (EPIAMNE) score—using quantitative EEG (qEEG) analysis to obtain a tool for differentiating TEA from TGA. We retrospectively reviewed clinical information and standard EEGs (stEEG) of 19 patients with TEA and 21 with TGA. We computed and compared Power Spectral Density, demonstrating an increased relative theta power in TGA. We subsequently incorporated qEEG features in EPIAMNE score, together with clinical and stEEG features. ROC curve models and pairwise ROC curve comparison were used to evaluate and compare the diagnostic accuracy for TEA detection of EPIAMNE score, presence of symptoms atypical for TGA (pSymAT) and identification of anomalies (interictal epileptiform or temporal focal spiky transients) at stEEG (PosEEG). Area Under the Curve (AUC) of EPIAMNE score revealed to be higher than PosEEG and pSymAT (AUC_EPIAMNE = 0.95, AUC_pSymAT = 0.85, AUC_PosEEG = 0.67) and this superiority proved to be statistically significant (p-value_{EPIAMNE-PosEEG} and p-value_{EPIAMNE-pSymAT} < 0.05). In conclusion, EPIAMNE score classified TEA with higher accuracy than PosEEG and pSymAT. This approach could become a promising tool for the differential diagnosis of AAS, especially for early TEA detection. Full article

Transient global amnesia (TGA) is a well-defined syndrome with temporarily impaired memory formation lasting several hours. Retrospective case series with diffusion-weighted magnetic resonance imaging (DWI) demonstrated that on average 5.4% of putative TGA cases are actually mimicked by strokes. To avoid a delay in stroke diagnosis – because DWI in TGA is usually deferred by a day or two – results from one large retrospective case series indicate that acutely elevated cardiac troponin levels will preselect those at highest risk of stroke as a TGA mimic and so are in need of urgent imaging and also cardiological work-up. Prospective studies will have to ascertain whether measuring troponin in suspected TGA will be helpful and improve outcome. Full article

Transient global amnesia (TGA) is defined by an acute memory disturbance of unclear aetiology for a period of less than 24 h. Observed psychological, neuroanatomical and hormonal differences between the sexes in episodic memory suggest sex-specific differences in memory disorders such as TGA. The aim of this study was to determine sex-specific differences in cardiovascular risk profiles, recurrences and magnetic resonance imaging (MRI). In total, 372 hospitalised TGA patients between 01/2011 and 10/2021 were retrospectively analysed. Comparisons were made between female and male TGA patients and compared to 216 patients with acute stroke. In our sample, women were overrepresented (61.8%), especially compared to the general population in the 65–74 age category (χ² = 10.6, p < 0.02). On admission, female TGA patients had significantly higher systolic blood pressure values and a higher degree of cerebral microangiopathy compared to male TGA patients, whereas acute stroke patients did not. No sex-specific differences were observed with respect to recurrences or hippocampal DWI lesions. Our data demonstrate sex-specific differences in TGA. The higher blood pressure on admission and different degree of cerebral microangiopathy in female TGA patients supports the theory of blood pressure dysregulation as a disease trigger. Distinct precipitating events in female and male patients could lead to differences in the severity and duration of blood pressure abnormalities, possibly explaining the higher incidence in female patients. Full article

Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of a temporary memory disorder with profound anterograde amnesia and a variable impairment of the past memory. Usually, the attacks are preceded by a precipitating event, last up to 24 h and are not associated with other neurological deficits. Diagnosis can be challenging because the identification of TGA requires the exclusion of some acute amnestic syndromes that occur in emergency situations and share structural or functional alterations of memory circuits. Magnetic Resonance Imaging (MRI) studies performed 24–96 h after symptom onset can help to confirm the diagnosis by identifying lesions in the CA1 field of the hippocampal cornu ammonis, but their practical utility in changing the management of patients is a matter of discussion. In this review, we aim to provide a practical approach to early recognition of this condition in daily practice, highlighting both the lights and the shadows of the diagnostic criteria. For this purpose, we summarize current knowledge about the clinical presentation, diagnostic pathways, differential diagnosis, and the expected long-term outcome of TGA. Full article

Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of a temporary memory disorder with a profound anterograde amnesia and a variable impairment of the past memory. Since the first description, dating back over 60 years, several cases have beenreported in the literature. Nevertheless, TGA remains one of the most mysterious diseases in clinical neurology. The debate regarding the etiology of this disease has focused mainly on three different mechanisms: vascular (due to venous flow changes or focal arterial ischemia), epileptic, and migraine related. However, to date there is no scientific proof of any of these mechanisms. Furthermore, the demonstration by diffusion-weighted MRI of lesions in the CA1 field of the hippocampus cornu ammonis led us to hypothesize that the selective vulnerability of CA1 neurons to metabolic stress could play a role in the pathophysiology of TGA. In this review, we summarize current knowledge on the anatomy, vascularization and function of the hippocampus. Furthermore, we discuss the emerging theories on the etiology and the pathophysiological cascade leading to an impairment of hippocampal function during the attacks. Full article

Transient epileptic amnesia (TEA) is a rare epileptic condition, often confused with transient global amnesia (TGA). In a real-life scenario, differential diagnosis between these two conditions can be hard. In this study we use power spectral analysis empowered by exact Low Resolution Brain Electromagnetic Tomography (eLORETA) to evidence the differences between TEA and TGA. Fifteen patients affected by TEA (64.2 ± 5.2 y.o.; 11 female/4 male; 10 left and 5 right temporal epileptic focus) and 15 patients affected by TGA (65.8 ± 7.2 y.o.; 11 females/4 males) were retrospectively identified in our clinical records. All patients recorded EEGs after symptoms offset. EEGs were analyzed with eLORETA to evidence power spectral contrast between the two conditions. We used an inverse problem solution to localize the source of spectral differences. We found a significant increase in beta band power over the affected hemisphere of TEA patients. Significant results corresponded to the uncus and para-hippocampal gyrus, respectively Brodmann’s Areas: 36, 35, 28, 34. We present original evidence of an increase in beta power in the affected hemisphere (AH) of TEA as compared to TGA. These differences involve key areas of the memory network located in the mesial temporal lobe. Spectral asymmetries could be used in the future to recognize cases of amnesia with a high risk of epilepsy. Full article

Jugular venous valve incompetence has no long-term remedy and symptoms of transient global amnesia and/or intracranial hypertension continue to discomfort patients. During this study, we interrogate the synergy of the collagen and elastin microstructure that compose the bi-layer extracellular matrix (ECM) of the jugular venous valve. In this study, we investigate the jugular venous valve and relate it to tissue-level mechanical properties, fibril orientation and fibril composition to improve fundamental knowledge of the jugular venous valves toward the development of bioprosthetic venous valve replacements. Steps include: (1) multi loading biaxial mechanical tests; (2) isolation of the elastin microstructure; (3) imaging of the elastin microstructure; and (4) imaging of the collagen microstructure, including an experimental analysis of crimp. Results from this study show that, during a 3:1 loading ratio (circumferential direction: 900 mN and radial direction: 300 mN), elastin may have the ability to contribute to the circumferential mechanical properties at low strains, for example, shifting the inflection point toward lower strains in comparison to other loading ratios. After isolating the elastin microstructure, light microscopy revealed that the overall elastin orients in the radial direction while forming a crosslinked mesh. Collagen fibers were found undulated, aligning in parallel with neighboring fibers and orienting in the circumferential direction with an interquartile range of −10.38° to 7.58° from the circumferential axis (n = 20). Collagen crimp wavelength and amplitude was found to be 38.46 ± 8.06 µm and 4.51 ± 1.65 µm, respectively (n = 87). Analyzing collagen crimp shows that crimp permits about 12% true strain circumferentially, while straightening of the overall fibers accounts for more. To the best of the authors’ knowledge, this is the first study of the jugular venous valve linking the composition and orientation of the ECM to its mechanical properties and this study will aid in forming a structure-based constitutive model. Full article

Transient global amnesia is an acute, benign, isolated and temporarily limited disturbance of memory, that can occur repeatedly but shows no increased risk of cardiovascular events or stroke in particular. Therefore, patients with the typical clinical presentation and a normal brain magnetic resonance-scan require neither further diagnostic nor therapeutic interventions. Since the differential diagnosis of transient global amnesia is wide, and transient ischaemic attacks can present similarly, a careful clinical evaluation and neuroimaging is recommended. In any case of doubt further diagnostic steps according to stroke workup should be initiated. In contrast, a transient ischaemic attack represents a neurological emergency where clinical and diagnostic evaluation must be introduced fast. The rapid establishment of therapeutic and secondary preventive measures decreases the clearly elevated stroke risk and prevents disability. Full article

This mini-review entertains the concept that transient global amnesia (TGA) could possibly be part of the spectrum of transient epileptic amnesia (TEA), which is considered the most important differential diagnosis by many clinicians. To support this hypothesis we analysed EEG data, where conventional scalp recording was unrevealing, but nasopharyngeal electrodes demonstrated epileptic discharges in the medial temporal lobe, the region implicated in memory dysfunction during transient global amnesia. Full article

Given the high variability of stroke mechanisms, size, localisation and degree of the penumbra, clinicians treating acute stroke patients need tools in addition to clinical information to match the individual patient with different available treatment strategies. Among the two types of perfusion CTs the dynamic perfusion CT is preferable over the whole-brain technique as it can generate truly quantitative regional cerebral blood volume and cerebral blood-flow values and threshold maps that may differentiate reversible from non-reversible ischaemia. Some drawbacks of perfusion CTs, such as the impossibility of serial examinations (amount of contrast, radiation) or failure to show lacunar or posterior fossa lesions, are counterbalanced by the availability of CTs in most emergency rooms, its easy accessibility, simple monitoring of patients and the possibility to quantify perfusion deficits. Perfusion CT has a sensitivity and positive predictive value above 90% for territorial infarcts in the supratentorial regions, even in the earliest phase of stroke. Dynamic perfusion CT reliably identifies penumbra and core tissue and closely predicts final stroke volume. The final stroke size is usually close to the initial core volume if early arterial recanalisation occurs, and close or equal to the initial core plus penumbra size if early recanalisation does not occur (with or without thrombolysis). TIAs or migraine, but not focal seizures or transient global amnesia, may rarely show minor focal hypoperfusion. In regard to information about supratentorial brain perfusion, it appears at least equivalent to MRI perfusion methods. Regarding treatment decisions, the degree of penumbra on perfusion CTs as well as an arterial occlusion on the angio CT could help to select between intraarterial and intravenous thrombolysis. Further studies might show that the current time windows thrombolyses are too long for patients with little penumbra and too short for patients with a persistent penumbra.Therefore, perfusion imaging may allow to replace a rigid time window for acute interventions and the saying “time is brain” might be replaced by “penumbra is brain”. Thus, even patients with unknown onset of stroke, waking up with a stroke or having an epileptic seizure at stroke onset may become candidates for treatment based on the demonstration of a significant penumbra on perfusion imaging. In case neuroprotective treatment becomes available, only patients with a significant penumbra involving the brain matter for which the substance is active (grey versus white brain matter) may be exposed to benefits, costs and side effects of these treatments. When testing new acute stroke therapies, a potential treatment effect may be better shown thanks to selecting patients with perfusion CTs who are more likely to respond to the treatment strategy. In such a study it could be the amount of salvage of the initial radiological penumbra on perfusion CTs that may be used as a surrogate marker to test the efficacy of a new intervention, rather than final infarct size. Full article