Amnesia Research Articles

Transient global amnesia and hippocampal diffusion restriction: an overlooked radiological finding.

Transient global amnesia (TGA) is characterized by isolated sudden anterograde amnesia. Diffusion restriction can be observed in the hippocampus on DWI-MRI at varying rates in TGA patients. This study analyzes the prevalence and characteristics of the hippocampal diffusion restriction (HDR), its relationship with vascular risk factors, and the prevalence of lesions overlooked in routine reports. 91 patients diagnosed with TGA at a tertiary hospital between 2011 and 2022 were evaluated retrospectively. The mean age was 64.8 ± 7.3years, and 63.7% of patients were female. 75.8% of the patients had at least one vascular risk factor. Focal diffusion restriction was detected in 17 patients (18.5%) on DWI-MRI, with only one being extra-hippocampal. 81.2% of HDR was detected when DWI-MRI scan was performed between 12 and 96h after the onset of symptoms. HDR was detected most when the imaging was performed in 24 to 48h (p = 0.03). There was no correlation between the duration of symptoms and the detection rates of HDR (p = 0.55). In 9 patients (53% of 17) diffusion restriction was not specified in routine radiology reports. Although focal ischemia, venous flow abnormalities, migraine and epileptic phenomena have been suggested in its etiology, TGA is a clinical condition of which pathophysiology has not been determined clearly. Signal changes observed in DWI-MRI has led to discussions that cerebrovascular etiology may play a role, yet more comprehensive studies are required to prevent and manage TGA. HDRs can be overlooked in routine reports. Therefore, the DWI-MRI images of patients with TGA should be examined vigilantly.

The Impact of Midazolam on Reducing Adverse Events during Bronchoscopy Procedures

Background: Bronchoscopy involves the examination of patient airways by advancing a bronchoscope into the lungs. This procedure is essential for diagnosing and treating respiratory disorders but comes with risks such as hypoxia and arrhythmias. Effective sedation techniques are necessary to mitigate these risks. This study assesses the impact of Midazolam on minimizing adverse events during bronchoscopy. Objectives: The aim is to evaluate the frequency of complications before and after IV Midazolam in patients who have undergone bronchoscopy. The secondary outcomes are the evaluation of the Midazolam’s systemic tolerability and safety in these patients, the rate of coughing and readiness to perform the procedure again. Study Design: A cross-sectional study Duration and place of study conducted in the Department of Pulmonology MTI/LRH from January 2021 to July 2021. Methods: 102 patients were enrolled in this cross-sectional study performed at MTI/LRH. Patients were randomly divided into two groups: Of the patients, 51 patients received Midazolam while 51 patients did not receive any form of sedation. The participants included 50% males and the mean age of the participants was 45 years (SD=12). Comparisons of side effects profiles and the incidences of adverse events were made between the two groups. Results : The rates of overall complications were higher in the Midazolam group where it was 10% and in no-sedation group it was 30%. The proportion of subjects with hypoxia decreased from 15% (the no-sedation group) to 5% (the Midazolam group). The relative risk of this was found to be 0. 3 indicating less occurrence of arrhythmias in the Midazolam group than in the no-sedation group; 3% in the Midazolam group while 10% in the no sedation group. The patients who used Midazolam to help them go through the procedure were also advised and confirmed that they had very little coughing and would attempt the procedure again. Further, Midazolam patients were examined to be having anterograde amnesia regarding the events that occurred during the procedure and the emergent side-effects. Conclusion : It is beneficial in preventing complications during the process of bronchoscopy, enhancing patient care, and is less uncomfortable to the patient; midazolam has an amnestics effect which in a way is good for the patient. It is recommend for use in case of complications of the procedure should occur.

Acute amnestic syndrome in fornix lesions: a systematic review of reported cases with a focus on differential diagnosis

IntroductionAcute amnestic syndrome is an uncommon clinical presentation of neurological disease. Differential diagnosis encompasses several syndromes including Wernicke-Korsakoff and transient global amnesia (TGA). Structural lesions of the fornix account for a minority of cases of acute amnestic syndromes. Etiology varies from iatrogenic injury to ischemic, inflammatory, or neoplastic lesions. A prompt diagnosis of the underlying pathology is essential but challenging. The aim of this review is to systematically review the existing literature regarding cases of acute amnestic syndrome associated with non-iatrogenic lesions of the fornix.MethodsWe performed a systematic literature search on PubMed, Scopus, and Web of Science up to September 2023 to identify case reports and case series of patients with amnestic syndrome due to fornix lesions. The systematic review was conducted according to PRISMA guidelines. The research was limited to articles written in English. Cases of fornix damage directly ascribable to a surgical procedure were excluded.ResultsA total of 52 publications reporting 55 cases were included in the review. Focusing on acute/subacute onset, vascular etiology was highly prevalent, being responsible for 78% of cases, 40/55 (74%) of which were due to acute ischemic stroke. The amnestic syndrome was characterized by anterograde amnesia in all patients, associated with retrograde amnesia in 27% of cases. Amnesia was an isolated presentation in most cases. Up to two thirds of patients had persistent memory deficits of any severity at follow-up.DiscussionAcute amnestic syndrome can be rarely caused by fornix lesions. In most cases of acute/subacute presentation, the etiology is ischemic stroke, mainly caused by strokes involving the subcallosal artery territory. The differential diagnosis is challenging and a distinction from common mimics is often difficult on a clinical basis. A high index of suspicion should be maintained to avoid misdiagnosis and provide adequate acute treatment to patients with time-dependent disease, also employing advanced neuroimaging. More research is needed to better understand the outcome and identify prognostic factors in patients with amnestic syndrome due to fornix lesions.

Rapid determination of alprazolam in gin tonic cocktails based on the coupling of IR spectroscopy and chemometrics: A feasibility study

“Drug-facilitated sexual assault" (DFSA) is a sexual assault perpetrated against a person rendered unconscious by a substance that changes her/his physical and/or mental condition, such as ethanol or drugs. Several active pharmaceutical ingredients, whether used alone or with alcoholic beverages, can produce anterograde amnesia and loss of inhibition. The most common pharmaceuticals found in DFSAs are GHB (-hydroxybutyric acid), benzodiazepines (Valium, Xanax, or Roipnol), antidepressants (Venlafaxine), muscle relaxants (cyclobenzaprine), antihistamines, sleeping pills (diphenhydramines), hallucinogens, and opioids. Biological samples are typically examined in cases of suspected DFSA; however, occasionally, samples are sent to labs a long period after being collected, jeopardizing the accuracy of the analysis. As a result, in recent years, the focus has shifted to directly detecting the presence of drugs in alcoholic beverages. In light of this, the purpose of the current study is to build a FT-IR-based approach for the determination of alprazolam in a common long drink (gin and tonic). To achieve this goal, pure (Class Pure) and spiked gin tonics (Class Spiked) were analyzed by Fourier-transform infrared spectroscopy (FT-IR). Afterward, two classifiers were used: Sequential preprocessing through ORThogonalization Linear Discriminant Analysis (SPORT-LDA) and Soft Independent Modeling of Class Analogies (SIMCA). Both approaches provided good results: SPORT-LDA achieved a 95% and a 98% accuracy rate (on the external test set of samples) for spiked and pure cocktails, respectively. This corresponds to the misclassification of 5 spiked and 1 pure drinks. The SIMCA model of class pure achieved 98.2% and 91.7% of specificity and sensitivity, respectively, coinciding with 55 pure samples (over 60) correctly accepted and 2 (over 110) erroneously rejected by the model. In conclusion, the SIMCA model of class pure seems preferable, because it minimizes the type II error. Eventually, the study was circumscribed to the spiked cocktails and a novel SPORT model was used to quantify alprazolam in spiked cocktails. This provided noteworthy results, in fact, it led to a Root Mean Square Error in Prediction (RMSEP) of 0.95, and a R2pred of 0.98.

Clinical Heterogeneity in Alzheimer's Disease: A Possible New Amnesic Phenotype.

We rediscovered a phenotype of AD known in the early 1900s as presbyophrenia, but then forgotten, and renamed as confabulation-misidentification phenotype. The phenotype includes diencephalic amnesia whose prototype is Korsakoff syndrome. The main features are anterograde and retrograde amnesia with marked disorientation and confabulation, executive impairments, reduced insight and attention deficits, misidentification, minor hallucination and other delusions, behavioral disturbances, and early anxiety. In this article, we summarize what we have discovered about the new phenotype and what is still missing to confirm this diencephalic variant of AD.

Transient global amnesia as a clinical manifestation of unilateral hippocampal infarction. Case report

Transient global amnesia (TGA) is a rare symptom complex characterized by a brief episode of severe fixation, anterograde and retrograde amnesia. The prevalence of TGA increases with age. Risk factors for this disease include physical overexertion, severe emotional stress, exposure to cold or hot water, hypothermia and pain. The diagnosis of TGA is based on the Kaplan and Hodges–Warlow criteria, according to which TGA is characterized by: complete resolution of mnestic disturbances within 24 hours; absence of other neurological and cognitive impairments; absence of previous head trauma or seizures. In cases where the clinical picture of TGA does not meet the criteria for the disease, a differential diagnosis should be performed, especially with cases of ischemic stroke in the vertebrobasilar region and transient epileptic amnesia. If acute ischemia is confirmed by the brain MRI results, further comprehensive diagnostic investigation must be performed to determine the subtype of acute cerebrovascular accident with further appropriate secondary prevention of cardiovascular complications. If a non-cardioembolic stroke type is identified, antiplatelet therapy has a crucial role. The clinical case of a patient with a left-sided hippocampal infarction clinically manifested by a TGA is presented.

Converging diencephalic and hippocampal supports for episodic memory

To understand the neural basis of episodic memory it is necessary to appreciate the significance of the fornix. This pathway creates a direct link between those temporal lobe and medial diencephalic sites responsible for anterograde amnesia. A collaboration with Andrew Mayes made it possible to recruit and scan 38 patients with colloid cysts in the third ventricle, a condition associated with variable fornix damage. Complete fornix loss was seen in three patients, who suffered chronic long-term memory problems. Volumetric analyses involving all 38 patients then revealed a highly consistent relationship between mammillary body volume and the recall of episodic memory. That relationship was not seen for working memory or tests of recognition memory. Three different methods all supported a dissociation between recollective-based recognition (impaired) and familiarity-based recognition (spared). This dissociation helped to show how the mammillary body-anterior thalamic nuclei axis, as well as the hippocampus, is vital for episodic memory yet is not required for familiarity-based recognition. These findings set the scene for a reformulation of temporal lobe and diencephalic amnesia. In this revised model, these two regions converge on overlapping cortical areas, including retrosplenial cortex. The united actions of the hippocampal formation and the anterior thalamic nuclei on these cortical areas enable episodic memory encoding and consolidation, impacting on subsequent recall.

A case of severe anterograde amnesia in the era of smartphone technology

ABSTRACT A.V. is a young herpes simplex encephalitis (HSE) survivor who suffered extensive bilateral damage to the medial temporal lobe (MTL) leading to a severe and pervasive form of anterograde amnesia. Structural Magnetic Resonance Imaging (MRI) revealed lesions that encompass the hippocampus and amygdala in both hemispheres and that extend more laterally in the right temporal lobe. At the same time, detailed neuropsychological testing showed that the disparity between A.V.’s preserved intellectual functioning (Full Scale IQ: 115) and severe memory deficit (Delayed Memory Index: 42) is one of the largest on record. Despite this deficit, A.V. has regained a higher level of functioning and autonomy compared to previously documented amnesic cases with major bilateral MTL lesions. As a millennial, one advantage which A.V. has over prior amnesic cases is fluency with digital technology – particularly the smartphone. The analysis of his phone and specific app usage showed a pattern that is consistent with the strategy to offload cognitive tasks that would normally be supported by the MTL. A.V.’s behavior is significant in terms of rehabilitation and may have broader implications at the societal level and for public health given the ubiquity of smartphone technology and its potential to become integrated with neural mnemonic functions.

Isolated bilateral fornix anterior columns infarction with acute amnesia and fiber tracts damage, a case report

ABSTRACT Isolated fornix anterior column infarction has rarely been described and is difficult to assess accurately using conventional magnetic resonance imaging (MRI). We report the case of a 75-year-old female who experienced acute anterograde amnesia. MRI performed within 24 h after amnesia onset showed an isolated infarction of the bilateral anterior columns of the fornix on diffusion-weighted imaging (DWI). Her symptoms persisted for up to 50 days, and diffusion tensor imaging (DTI) showed disruption of the fiber tracts of the fornix. when acute amnesia syndrome onset, fornix anterior column infarction should be considered, and optimized DWI and DTI methods are needed to study the fornix in vivo in future research.

85 Evaluating the Improvement on the Naturalistic Action Task After the Virtual Kitchen Intervention: A Case Study

Objective:The goal-control model of the functional impairment in dementia posits two different underlying mechanisms: decay of task goals (reduced task accomplishment) and poor control over goal execution (high error rates). Here we present a case series in which we explore the effects of a performance-based, functional intervention on two participants. Outcomes were evaluated using the goal-control framework.Participants and Methods:Two participants with dementia (CS: age 70, 14 years of education; EM: age 93, 18 years of education) completed neuropsychological tests (scored using age, education, and IQ-adjusted norms) and baseline testing with the Naturalistic Action Task (NAT; a validated performance-based task of everyday function including a Breakfast and Lunch task). The Virtual Kitchen (VK) was used to train, through repeated performance, either the Breakfast (CS) or Lunch (EM) tasks for 30 minutes (or 10 total repetitions) per day over 5 days. After VK training, participants performed the NAT Breakfast and Lunch tasks again to evaluate improvement on the trained and untrained tasks. Baseline and post-training NATs were scored for task accomplishment and errors by two coders observing video recordings. Z scores were derived by calculating accomplishment and error change scores for each participant relative to the mean and standard deviations of change scores from a cohort of 36 healthy controls (mean age: 73.3, SD: 6.44; mean education: 17.42, SD: 2.17).Results:Both participants exhibited similar cognitive profiles: high estimated IQ; low MMSE (total = 19 for both CS and EM; 1st percentile); anterograde amnesia, slowed processing speed and impaired executive function; average scores on tests of attention, language, and self-reported depression. Informant report of daily functioning (FAQ) suggested that EM (FAQ=28) exhibited greater functional impairment than CS (FAQ=9). Both participants completed all VK training sessions. Z scores of the change from pre- to post-training showed significant increases in task accomplishment on the trained task (trained condition change z scores: EM = +27.69; CS =+ 6.06), but significantly less improvement or worse task accomplishment on the untrained task (untrained condition change z scores: EM = +4.06; CS = -13.69). The training did not reduce errors, as error rates increased for both participants on the trained task.Conclusions:The participants presented in this case study exhibited comparable cognitive profiles, including marked anterograde amnesia. Our results suggest that repeated training in a virtual context can improve specific aspects of functioning on real, life everyday tasks. Further, according to the goal-control framework, repeated practice reduces the decay of the task goal, as represented by greater task accomplishment, but does not improve executive control over the task execution. Important future directions are to determine if people with different cognitive profiles will demonstrate different benefits from VK training and to examine if virtual training of personally relevant, everyday tasks can promote independent living and improve quality of life.

A - 161 Acute Injury Characteristics and Cognitive Post-Concussion Symptom Reporting in Collegiate Athletes with Sports-Related Concussion.

Surprisingly little is known about how acute injury characteristics (i.e., loss of consciousness [LOC], retrograde amnesia [RA], and anterograde amnesia [AA]) predict cognitive symptom reporting after sports-related concussion (SRC). This study examined this relationship in collegiate athletes who sustained an SRC. We predicted that athletes who endorsed LOC, RA, and AA would report more cognitive symptoms. 141 collegiate athletes who recently sustained an SRC were grouped based on whether they experienced LOC, RA, or AA. Cognitive symptoms were assessed by the cognitive cluster of the Post Concussion Symptoms Scale (PCSS-Cog) both categorically (i.e., presence of symptoms) and continuously (i.e., total score). Chi-square tests investigated group differences on the presence of cognitive symptoms, and independent samples t-tests examined group differences on PCSS-Cog scores. Athletes who experienced RA were significantly more likely to report cognitive symptoms than those without RA (RA+/PCSS-Cog+ = 62.50%; RA-/PCSS-Cog+ = 40.17%), X2 (1, N = 141) = 4.03, p = 0.045. Similar results were observed for athletes who endorsed AA (AA+/PCSS-Cog+ = 58.82%; AA-/PCSS-Cog+ = 35.56%), X2 (1, N = 141) = 7.15, p = 0.007. There was not a significant relationship between cognitive symptom endorsement and LOC. Athletes who experienced AA had significantly higher PCSS-Cog scores (M = 3.27, SD = 4.60) than those without AA (M = 1.39, SD = 3.04), t(75.22) = 2.62, p = 0.011, 95% CI[0.45, 3.32]. However, there was not a significant relationship between PCSS-Cog scores and LOC or RA. Results suggest that athletes who experience amnesia during SRC are more likely to report cognitive symptoms post-concussion. Moreover, amnesia may be a risk factor for increased self-reported cognitive dysfunction, and athletes who experience RA and especially AA may require more careful SRC management.

On the participation of adenosinergic receptors in the reconsolidation of spatial long-term memory in male rats.

To date, there is insufficient evidence to explain the role of adenosinergic receptors in the reconsolidation of long-term spatial memory. In this work, the role of the adenosinergic receptor family (A1, A2A, A2B, and A3) in this process has been elucidated. It was demonstrated that when infused bilaterally into the hippocampal CA1 region immediately after an early nonreinforced test session performed 24 h posttraining in the Morris water maze task, adenosine can cause anterograde amnesia for recent and late long-term spatial memory. This effect on spatial memory reconsolidation was blocked by A1 or A3 receptor antagonists and mimicked by A1 plus A3 receptor agonists, showing that this effect occurs through A1 and A3 receptors simultaneously. The A3 receptor alone participates only in the reconsolidation of late long-term spatial memory. When the memory to be reconsolidated was delayed (reactivation 5 d posttraining), the amnesic effect of adenosine became transient and did not occur in a test performed 5 d after the reactivation of the mnemonic trace. Finally, it has been shown that the amnesic effect of adenosine on spatial memory reconsolidation depends on the occurrence of protein degradation and that the amnesic effect of inhibition of protein synthesis on spatial memory reconsolidation is dependent on the activation of A3 receptors.

Errorful learning improves recognition memory for new vocabulary for people living with memory and dysexecutive impairment following brain injury

ABSTRACT A widely accepted view is that errorless learning is essential for supporting new learning in people with anterograde amnesia, but findings are mixed for those with a broader range of memory impairments. People at a chronic stage of recovery from brain injury (BI) with impaired memory and executive function (N = 26) were compared with adults in a comparison group without any known risks to brain function (N = 25). Learning techniques were compared using a “Generate-and-correct” and “Read-only” condition when learning novel word pairs. At test, both groups scored above chance and showed benefits of Generate-and-correct (errorful learning). Poor learners in the BI group were classified from “flat” learning slopes extracted from an independent word-pair learning task. Critically, poor learners showed no benefit, but also no decrement to learning, using the Generate-and-correct method. No group was harmed by errorful learning; all, except the poorest learners, benefitted from errorful learning. This study indicates, that in some rehabilitation settings, encouraging clients to guess the meaning of unfamiliar material (e.g., from cards, magazines, newspapers) and then correct their errors, could have benefits for recognition memory. Determining when and how errorful learning benefits learning is a key aim for future research.

Benzodiazepine-induced anterograde amnesia: detrimental side effect to novel study tool.

Benzodiazepines (BZDs) are anxiolytic drugs that act on GABAa receptors and are used to treat anxiety disorders. However, these drugs come with the detrimental side effect of anterograde amnesia, or the inability to form new memories. In this review we discuss, behavioral paradigms, sex differences and hormonal influences affecting BZD-induced amnesia, molecular manipulations, including the knockout of GABAa receptor subunits, and regional studies utilizing lesion and microinjection techniques targeted to the hippocampus and amygdala. Additionally, the relationship between BZD use and cognitive decline related to Alzheimer's disease is addressed, as there is a lack of consensus on whether these drugs are involved in inducing or accelerating pathological cognitive deficits. This review aims to inspire new research directions, as there is a gap in knowledge in understanding the cellular and molecular mechanisms behind BZD-induced amnesia. Understanding these mechanisms will allow for the development of alternative treatments and potentially allow BZDs to be used as a novel tool to study Alzheimer's disease.

Severe hypocalcemia as a cause of transient ischemic attack? A debatable case and evidence from literature.

Hypocalcemia and transient ischemic attack (TIA) are different medical disorders; however, limited evidence suggests a possible link between the two. The underlying pathomechanisms by which hypocalcemia may cause cerebrovascular damage are difficult to comprehend. The aim of the study was to present an individual experiencing TIA that possibly due to severe hypocalcemia that associated with hypoparathyroidism after total thyroidectomy; and to explore the available evidence of its cause-effect relationship through available literature. A 68-year-old man presented to Dr. Zainoel Abidin Hospital, Banda Aceh, Indonesia with complaints of weakness, especially in the right limbs that had worsened in the last week. The patient experienced unconsciousness for an hour before the admission; disorientation and anterograde amnesia over the time of recovering of consciousness. Other complaints included frequent muscle cramps, numbness in both arms and legs, dizziness, swallowing difficulty, nausea, and vomiting. The patient had a history of total thyroidectomy for a large struma diffuse 18 years ago and was prescribed several medications. However, the patient was overwhelmed by forgetfulness which had become more frequent in recent months resulting in medication nonadherence. The vital sign was stable and Chovsteck's sign was positive. The Montreal Cognitive Assessment (MoCA) revealed impairment in the visuospatial/executive component and delayed memory. Laboratory tests revealed severe hypocalcemia, altered thyroid function, hypomagnesemia, elevated D-dimer and fibrinogen, and vitamin D deficiency. TIA and severe hypocalcemia were proposed as the diagnosis. Prompt initiation of appropriate treatment, including calcium supplementation, anticoagulation, and neuroprotective agents, led to significant clinical improvement. Evidence from available literature suggests that there is a possible link between severe hypocalcemia and TIA that occurred in this patient. However, more studies are warrant to establish this cause-effect relationship.

Examining Alcohol-Related Blackouts and Drinking Motives Over Time Among College Women.

Excessive alcohol consumption and its consequences among college women continues despite prevention efforts. One common consequence, alcohol-related blackouts (ARBs), are periods of alcohol-activated anterograde amnesia. The purpose of the current project is to extend the ARB and drinking motive literature by examining their relationship over time. A sample of 424 women (88.9% White) completed online surveys assessing their ARBs and drinking motives weekly for 10 weeks. A series of hierarchical generalized linear models were estimated to examine the between-person and within-person effects of each drinking motive on repeated measures of experiencing a blackout across the time points. Women who report higher levels of drinking motives compared with others were more likely to report having blackout experiences. College women who reported higher levels of conformity motives did not have increased odds of experiencing a blackout. In weeks when they reported elevated levels of drinking motives, they were also more likely to experience an ARB. In general, college women who reported higher levels of social, coping, or enhancement motives experienced more blackouts than students who reported lower levels of these motives. Women who were underage were more likely to experience a blackout compared with women who were 21 or older. In a given week, 52.6% to 70.7% of the students consumed alcohol, and among women who drank in a given week, the prevalence of blackouts ranged from 8.5% to 14.6%. The results suggest that changes in motivational levels might provide a possible intervention point for ARBs risk.

Wernicke-Korsakoff Syndrome associated with hyperemesis gravidarum and fetal death: Case report and literature review

We describe a clinical case of a pregnant patient with hyperemesis gravidarum who progressed to abortion, Wernicke's encephalopathy, and Korsakoff's psychosis, all related to thiamine deficiency. The patient presented symptoms of disorientation, nonspecific limb movements, and fever, initially treated with metronidazole and ceftriaxone for suspected infected abortion. Subsequently, the patient was diagnosed with retained and infected abortion, and thiamine replacement therapy was initiated with an intravenous loading dose of 900 mg/day. During hospitalization, the patient presented with tetraparesis, nystagmus, decreased level of consciousness, anterograde and retrograde amnesia, confabulation, and aphasia. Magnetic resonance imaging showed lesions in the pons, typical of Wernicke's encephalopathy. The patient was empirically treated with acyclovir and ampicillin and showed clinical improvement. The text also provides a brief narrative review of the literature on the topic.

Retrospective analysis of cases of transient global amnesia admitted to the hospital

Introduction. Transient global amnesia (TGA) is a clinical syndrome, the main clinical manifestation of which is sudden development of anterograde and retrograde amnesia, lasting not more than 24 hours, without other general cerebral or focal neurological symptoms.The aim of the work was to reveal the peculiarities of clinical manifestations and data of additional methods of examination of patients with TGA syndrome referred to the primary vascular department with suspected acute cerebral circulation disorder (ACCD).Materials and methods. The study included 16 patients with transient global amnesia diagnosed according to the diagnostic criteria of Hodges and Warlow (1990). All patients underwent a detailed neurological and general medical examination. Electrocardiography, multispiral computer tomography of the head, echocardiography, ultrasound duplex scanning of the main arteries of the head and neck, laboratory examination (lipid spectrum) were performed. The Brief Mental Status Rating Scale was used to assess cognitive impairment.Results. The majority of patients had elevated blood pressure (BP). The leading trigger factor of transient global amnesia was stress. The duration of amnesia ranged from 1.5 to 5 hours. There was a significant impairment of short-term memory. On the first and second days of hospitalization, 50% of patients had normal cognitive functions on a brief mental status assessment scale, but by the 5th−7th day only 12.5 % of patients had abnormalities. Ultrasound markers of atherosclerosis in the form of intima-media complex thickening and dyslipidemia were found in 6 patients. Signs of left ventricular hypertrophy were found in the majority of patients. Discussion TGA is a relatively rare condition and an understudied syndrome. Due to its suddenness of clinical manifestation, TGA requires differential diagnostics with acute cerebral circulatory disorders, epilepsy, acute hypertensive encephalopathy and psychogenic amnesia.Conclusion. The clinical features of TGA identified in the patients were a history of arterial hypertension, elevated BP during an episode of TGA. The leading provoking factor was stress. TGA episode occurred predominantly in the first half of the day. The majority of patients had complaints of headache on admission. Cognitive disorders detected in patients on the first and second days of the disease quickly regressed to normal. Left ventricular hypertrophy was detected in most patients.

Epigenetic Processes of DNA Methylation Are Selectively Involved in the Mechanisms of Retrograde and Anteograde Amnesia.

The participation of DNA methylation processes in the mechanisms of anterograde and retrograde amnesia caused by impaired reconsolidation of conditioned food aversion memory by NMDA glutamate receptor antagonists or serotonin receptor antagonists, respectively, were studied on grape snails. Anterograde amnesia was characterized by impaired formation of long-term memory during repeated learning. Administration of a DNA methyltransferase (DNMT) inhibitor to amnestic animals resulted in accelerated formation of long-term memory during 1 day of repetitive training vs 3 days during initial training. In serotonin-dependent retrograde amnesia, repeated learning without DNMT inhibitor administration or after inhibitor injections led to the formation of long-term memory. The dynamics of memory formation was similar in both cases and did not differ from that during the initial training: the memory was formed within 3 days of training. Thus, epigenetic processes of DNA methylation are selectively involved in the mechanisms of anterograde amnesia, but do not participate in the mechanisms of retrograde amnesia.

Unusual stroke cause: bilaterally fornix infarction in a patient with biotinidase deficiency.

Learning points for clinicians Fornix is a white matter tract bundle that is a substantial component of the Papez Circuit and has memory and cognitive functions. Isolated bilateral fornix infarction is uncommon and the clinical presentation is memory impairments in general. Most cases are accompanied by vascular comorbidities such as pulmonary embolism and peripheral venous thrombosis. Here we presented an unusual case of bilaterally fornix infarction with biotinidase deficiency and presenting with paraparesis and acute onset anterograde amnesia.