Etiology Of Transient Global Amnesia Research Articles

Vertebral artery hypoplasia and hemodynamic impairment in transient global amnesia: a case control study.

The aetiology of transient global amnesia (TGA) is still a matter of debate. Besides ischemia of the mesial temporal lobe including the hippocampus, migraine-like mechanisms, epileptic seizures affecting mnestic structures, or venous congestion in the (para) hippocampal area due to jugular vein insufficiency have been discussed. We assessed the diameters of the intracranial arteries of TGA patients compared to controls to identify differences that support the hypothesis of reduced hippocampal perfusion as a pivotal factor in the pathophysiology of TGA. We reviewed magnetic resonance imaging time of flight angiographies (TOF-MRA) that were acquired during in-patient treatment of 206 patients with acute TGA. The diameters of the vertebral artery (VA) in the V4 segment, the proximal basilar artery, and the internal carotid arteries were measured manually. We compared the findings with TOF-MRA images of an age and sex matched control group of neurological patients without known cerebrovascular pathology. In TGA patients the diameter of the right VA was significantly (p < 0.01) smaller compared to controls (2.09 mm vs. 2.35 mm). There were no significant differences in the diameters of the other vessels. Only the fetal variant of the posterior cerebral artery was slightly more common in TGA. The smaller diameter (hypoplasia) of the right VA supports the hypothesis of a contribution of hemodynamic factors to the pathophysiology of TGA. The fact that hypoplasia represents a congenital condition might be the explanation why previous studies failed to find an increased rate of the classical (acquired) vascular risk factors.

The Significance of Atrial Fibrillation in Patients With Transient Global Amnesia.

Background and PurposeThe etiology of transient global amnesia (TGA) remains unclear in a large subset of patients. We aimed to determine the clinical and radiological characteristics of TGA-patients with suspected acute micro-embolic stroke on diffusion-weighted imaging (DWI).MethodsTGA-patients that had new DWI hippocampal lesions (DWI+) were compared to DWI negative TGA-patients (DWI–). Demographics, risk factors, clinical data, radiological data, and mortality were analyzed.ResultsOut of 83 patients diagnosed with TGA, 56 (65%) underwent MRI during the acute hospitalization and 26 (46%) had new hippocampal DWI lesions. DWI+ patients more often had a history of atrial fibrillation (AF, 26 vs. 7%, p = 0.04) but the frequency of other risk factors did not differ. None of the patients died, however, two DWI+ patients had subsequent stroke during a 2-year follow up and both had AF. In contrast, none of the DWI- patients had recurrent events.ConclusionAF is common among DWI+ TGA-patients. The presence of AF in patients with TGA could suggest an increased risk of subsequent stroke.

Chronobiology of transient global amnesia

IntroductionThe etiology of transient global amnesia (TGA) is still a matter of debate. Based, among others, on the observation of a close temporal relation between certain events and subsequent TGA episodes, recent proposals discuss the relevance of stress-associated processes impacting on hippocampal functioning. Circadian, infra- and ultradian rhythmicity has been found to play a relevant role in the multifactorial pathomechanisms of various disorders but has not been thoroughly studied in TGA.MethodsData of patients with a final diagnosis of TGA were collected in Mannheim, Germany (06/1999–01/2018, n = 404), and in the Kansai district, Japan (04/2006–03/2018, n = 261). Chronological patterns of TGA occurrence were determined.ResultsSignificant circadian rhythmicity of TGA occurrence with bimodal peaks (mid-morning, late afternoon) was found for the entire population (p = 0.002) and for either sub-cohort (Mannheim: p = 0.003, Kansai: p = 0.007). This finding was confirmed for either sex (women: p = 0.004, men: p = 0.004) and different age groups (< 65 years: p = 0.0009, ≥ 65 years: p = 0.003). There was no variation according to day of the week, month or season, but the proportion of patients with a weekday episode was significantly higher in the Mannheim cohort (p = 0.002).DiscussionWe identified a robust circadian rhythm in TGA occurrence which remarkably applied to either of the two study sites located on different continents and which was independent of sex and age. In light of abundant evidence of circadian rhythmicity of both, components of the human stress response system and memory, chronobiological analyses may provide an opportunity to further uncover the mechanisms underlying TGA.

MON-LB056 A Case of Transient Global Amnesia and Pituitary Tumor

Introduction Transient Global Amnesia (TGA) is benign clinical syndrome of reversible anterograde amnesia that occurs in middle-aged and older individuals. Only few cases on literature have reported co-occurrence of TGA and pituitary lesion. Case Presentation 72 year old man with history of hypertension, hyperlipidemia, coronary artery disease presented with a transient amnestic state where he appeared confused unable to recall the time, asking multiple times and forgetting things they had discussed repeatedly. The anterograde amnestic episode lasted approximately 5 hours and there was no motor weakness, aphasia, conscious disturbance or any other focal neurological deficit. Patient returned fully to his baseline. Prior to this event he was in good health, no excess headache, no vision issues, no increase in size of hands or feet, and no history of head trauma. CT head noted note a mass in the left sella extending into the cavernous sinus. CT perfusion of head and neck demonstrated no significant stenosis. MRI brain characterized a hypointense T1-weighted sequence with homogeneous contrast enhancement eroding the dorsum sella measuring 1.5 x 1.4 x 1.4 cm. The pituitary gland is not well separated from this mass and the basilar and internal carotid arteries were patent. Labs show prolactin to be >1000,testosterone and LH was low but FSH, Free T4, TSH, ACTH, am cortisol, IGF-1 were normal range. Labs showed normal electrolytes and normal glucose level. Discussion TGA is an isolated, sudden and self-limited disturbance of anterograde amnesia lasting less than 24horus and unaccompanied by other focal neurological deficits or seizure. The etiology of TGA is not completely clear with hypotheses including migrainous or epileptic phenomenon, vascular with transient interruption of vascular perfusion of memory related structure versus psychogenic disorder theory. In our case the CT and MR imaging studies disclosed a case of pituitary mass. The markedly high serum prolactin level and imaging finding are suggestive of prolactin-producing adenoma, although histological confirmation was not obtained. Literature review has showed a case of TGA presenting with hemorrhagic pituitary adenoma or pituitary apoplexy, postulating that the compression from bleeding adenoma affecting the memory eloquent pathways of hyppocampus.On our index case there is no exact anatomical relationship with memory related structure. It is not clear if TGA and pituitary adenoma finding on our patient is due to a chance of concurrence or it has etiological association. Although TGA is considered as a benign and functional disorder, neuroimaging need to be obtained to exclude organic causes of amnesic events. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Vascular risk factors and internal jugular venous flow in transient global amnesia: A study of 165 Japanese patients

Background: The etiology of transient global amnesia (TGA) remains unclear.

Vascular Risk Factors and Internal Jugular Venous Flow in Transient Global Amnesia: A Study of 165 Japanese Patients

The etiology of transient global amnesia (TGA) remains unclear. We studied the pathophysiology of TGA in 165 Japanese patients. TGA was diagnosed in hospitalized patients from 2004 to 2015. We analyzed clinical characteristics, magnetic resonance imaging findings, and maximum intima-media thickness of the common carotid artery, and the reflux of internal jugular venous (IJV) flow by ultrasonography, and statistically compared patients with TGA with age-matched and sex-matched patients who have had a transient ischemic attack (TIA), small-vessel occlusion (SVO), and normal controls (each group, N = 165). Patients with TGA showed lower prevalence of vascular risk factors than patients with TIA and SVO did. Eleven patients (6.7%) had 2 episodes of TAG, but specific clinical variables could not be recognized in these patients. The maximum intima-media thickness was significantly thinner in TGA (1.1 ± .7 mm) than in SVO (1.6 ± .9 mm; P = .001). The percentages of cases whose IJV flow reflux was increased by Valsalva maneuver showed no difference (P = .573) between TGA (26.0 %) and SVO (29.4%). MR diffusion-weighted imaging yielded small hyperintense signals in the hippocampus in 64 of 90 (71.1%) patients between 24 and 72 hours. Potential precipitating specific factors or events before the attacks could be recognized in 40 cases (24.2%) of 165 patients. Arterial ischemia and IJV flow reflux might not contribute to TGA pathophysiology. The vulnerability of the hippocampus to physical or emotional stress might be suspected as an underlying mechanism in some patients with TGA.

Prevalence of obstructive sleep apnea syndrome in a population of patients with transient global amnesia

ObjectiveThe etiology of transient global amnesia (TGA) is largely undetermined. The aim of this study was to investigate whether the prevalence of obstructive sleep apnea syndrome (OSAS), a condition associated with subtle changes in brain structures involved in memory processes, increases in subjects who have previously experienced a TGA episode. MethodsTwenty-nine patients who had had a TGA episode were included. A case–control model was used, matching cases with controls by sex, age, and body mass index category. Diagnosis of OSAS was based on the results of the Berlin Questionnaire, which was later confirmed by means of an all-night polysomnography recording. ResultsThe prevalence of OSAS among TGA patients was significantly higher with respect to that in controls (44.8% vs 13.8%, p = 0.020, χ2 test). At logistic regression model, subjects with TGA had an odds ratio of 8.409 (95% confidence interval = 1.674–42.243; p = 0.010) of having OSAS when compared with controls. ConclusionsAccording to our findings, an accurate investigation of sleep disturbances could be considered for a complete assessment of patients with TGA. The subtle cerebral anatomo-functional damage induced by the repeated nocturnal apneic episodes may be a pathophysiologic link between OSAS and TGA.

Obstruction of Venous Drainage Linked to Transient Global Amnesia.

Abnormal extracranial venous drainage modality has been considered an etiology of transient global amnesia (TGA). Evidence suggests that the transmission of the intrathoracic/intraabdominal pressure during a Valsalva maneuver (VM) is mainly through the vertebral venous system, and patency of internal jugular vein (IJV) is essential for venous drainage and pressure releasing. We hypothesize that obstruction of IJV venous drainage is a contributing factor in TGA pathogenesis. A magnetic resonance (MR) imaging protocol was used in 45 TGA patients and 45 age- and sex-matched controls to assess the morphologies of IJV, brachiocephalic vein (BCV) and asymmetry of transverse sinus (TS). The IJV was divided into the upper- and middle-IJV segments. Compared to the controls, TGA patients had significantly higher rates of moderate and severe compression/stenosis at the bilateral upper-IJV segment (left: 37.8% vs. 17.8%, P = 0.0393; right: 57.8% vs.15.6%, P<0.0012), in left BCV (60% vs. 8.9%, P<0.0004), and in TS hypoplasia (53.3%% vs. 31.1%, P = 0.0405). The prevalence of at least one site of venous compression/stenosis in IJV or BCV was significantly higher in patients than in controls (91.1% vs. 33.3%, P<0.0004). The diameter of the left TS in MRV, but not in T1 contrast imaging, was significantly smaller in TGA patients than in controls (0.31±0.21 vs. 0.41±0.19, P = 0.0290), which was compatible with downstream venous stenosis/obstruction. TGA patients have a higher prevalence of compression/stenosis of the bilateral IJV and the left BCV and TS hypoplasia, which is new evidence that supports the role of extracranial veins in TGA pathogenesis.

Transient Global Amnesia as a Presenting Manifestation of Cerebral Venous Thrombosis

Transient Global Amnesia as a Presenting Manifestation of Cerebral Venous Thrombosis

The Still Enigmatic Syndrome of Transient Global Amnesia: Interactions Between Neurological and Psychopathological Factors.

Transient global amnesia (TGA) is a neurological syndrome that usually occurs in middle-aged or older people. It is characterized by the abrupt onset of profound anterograde amnesia, associated with more variable retrograde amnesia and repetitive questioning. The whole episode lasts no more than 24 h. Almost 60 years after its first descriptions, the etiology of TGA remains unknown. Until now, TGA has been described exclusively as a memory disorder, but there is a growing body of evidence to show that emotional and psychological factors (as anxious and depressive symptoms) are present at different times of TGA. Their role therefore needs to be clarified. First, these factors seem to play a part in triggering TGA, at least for a subgroup of patients, suggesting the existence of an emotional TGA subtype. Second, recent research shows that almost all the TGA patients displayed modifications of their emotional state during the episode, possibly linked to sudden memory loss. The level of depressive and anxious symptoms could even reach a pathological threshold in patients with the so-called "emotional TGA subtype". Third, the persistence of these depressive and anxious symptoms after the end of the episode could account for lasting memory disorders in some patients. Finally, the analysis of these emotional syndrome and emotional factors and the recent data in neuroimaging could allow us to gain a better understanding of the pathophysiological mechanisms behind TGA. The aim of this review was thus to discuss whether the anxious and depressive symptoms are causative, resultant or coincidental of TGA.

Bilateral hippocampal abnormalities in magnetic resonance imaging in transient global amnesia

Transient global amnesia (TGA) is an isolated amnesic syndrome with normal neurologic examination. Patients remain alert and communicative with no loss of personal identity; however, they experience striking loss of memory for recent events and an impaired ability to retain new information. We report a case of TGA in a patient with acute ischemia in bilateral hippocampal abnormalities. This provides evidence in support of an ischemic hypothesis as the possible etiology of TGA.

The Clinical Factors Related with Hippocampal Lesion of Diffusion MRI in Transient Global Amnesia (P03.150)

Objective: We purposed to evaluate the difference of clinical factors between patients showed the hippocampal lesions in diffusion weighted image (DWI) of MRI and not in Transient global amnesia(TGA). Background TGA is an under-recognized but the lesion in hippocampal CA1 neuron is related to the amnestic event as in current reports. And psychiatric stress is the most common factor in etiology of TGA with or without MRI abnormality. As developing imaging methods, the detection rate of probable ischemic lesions by MRI is highly increased. The study about relations between clinical factors and MRI abnormality was rare. Design/Methods: Among TGA patients admitted to our hospital between July 2006 and May 2011, we retrospectively evaluated 121 patients with brain MRI within 120 hours of symptom onset for analysis and reviewed. Thirty-five of 121 patients had ipsilateral or bilateral hippocampus lesion which is probably the acute ischemic lesion detected by DWI. We defined this group as TGA with hippocampus lesion (TGAh). The TGA patients who have no lesion in hippocampus were defined as TGA with no lesion (TGAn). Results: The mean age of 121 TGA patients (female 74) was 60.6±11.0 years. The average duration of TGA was 8.0±7.62 hours. In TGAh group, mean age was 58.9±7.6 years and sex ratio was M/F : 11/24. In TGAn group, mean age was 61.4±12.1 years and sex ratio was M/F : 36/50. Compared with TGAn group, TGAh group more frequently had a history of psychiatric diseases (OR 21.25, 95% CI: 2.50-180.32), previous TGA history (OR 7.00, 95% CI: 1.29–38.01) and emotional stress (OR 5.76, 95% CI: 2.12-15.66). Conclusions: We propose that acute hippocampal lesion in TGA patients is related to emotional stress, psychiatric disease and previous TGA history. The cardio-vascular factors were not to be significant correlation. Disclosure: Dr. Cho has nothing to disclose. Dr. Kim has nothing to disclose.

Internal Jugular Vein Valve Incompetence in Transient Global Amnesia

See related article, pages 67–71. Transient global amnesia (TGA) was generally believed to have a psychogenic, epileptic, or thromboembolic etiology until the frequent comorbidity with migraine and the common accompanying symptoms (headache and dizziness) pointed toward cortical spreading depression as a pathogenic suspect.1,2 More recently, based on evidence that Valsalva-like activities may represent the precipitating factors in most TGA patients, cerebral venous congestion leading to venous ischemia was hypothesized as a possible pathophysiologic mechanism.3 Corroborating this hypothesis, the prevalence of internal jugular vein (IJV) valve incompetence, as assessed by ultrasound, was found to be more prevalent in patients with TGA than in controls.4–8 In all of these studies, IJV valve incompetence was detected in 97 of 131 patients (74%) and in 65 of 191 controls (34%). In this issue of Stroke, Cejas and coauthors9 confirmed these findings in a larger population, reporting IJV valve insufficiency in 113 patients with TGA (79.5%) and in 10 controls (25%). Apparently, this could solve …

Small dot lesion of transient global amnesia in diffusion-weighted coronal image: Location of the lesion in the hippocampus

Background and purpose: The transient global amnesia (TGA) is a rare amnestic syndrome that is characterized by a sudden onset of a selective antero- and retrograde-amnesia and for which the time course is limited up to 24 h. Interestingly, recent studies have reported a high frequency of small high signal abnormalities in the hippocampus with diffusion-weighted imaging (DWI) and ischemia has been proposed as an etiology of TGA. We hypothesized that the TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia.

Aortic dissection as a possible cause of pure transient global amnesia: a case report and literature review

A 55-year-old man suddenly developed anterograde and retrograde amnesia. His colleagues witnessed the onset of the episode and reported that 2 h before the onset of the amnesic attack the patient transiently became pale. Physical examination was unremarkable and neurological examination revealed no focal neurological sign although a laboratory investigation revealed leukocytosis. Pure transient global amnesia (TGA) was diagnosed. The anterograde amnesia resolved 20 h after onset, but the causes of his transient paleness precedent to TGA and leukocytosis were unclear. Thirty-four hours after onset, the patient complained of sudden back pain and radiological studies revealed aortic dissection (AD; Stanford type B). We emphasize AD as a rare cause of pure TGA, because TGA in itself often has a benign natural history, but AD can be life-threatening if undiagnosed. The precedent pain, transient systemic symptoms, and leukocytosis can be red flags suggesting AD as an etiology of TGA.

Cerebellar Hypoperfusion during Transient Global Amnesia: An MRI and Oculographic Study

Background and purposeTransient global amnesia (TGA) is characterized by sudden anterograde and retrograde amnesia lasting for up to 24 hours. Diffusion-weighted magnetic resonance imaging (DWI) in cases of TGA and ischemia demonstrates a high frequency of high signal intensities restricted to the hippocampus, and this has been proposed as an etiology of TGA. The aims of this study were to characterize the DWI and single-photon-emission computed tomography (SPECT) findings during the acute and recovered phases of TGA and to correlate the findings with oculomotor abnormalities.MethodsFive consecutive patients with a clinical diagnosis of TGA underwent DWI and SPECT of the brain within 24 hours after symptom onset and again 3 days later. Eye movements were also recorded using three-dimensional video-oculography.ResultsIn all patients, DWI disclosed small punctuate (1-3 mm), high-signal lesions in the lateral portion of the hippocampus. The initial SPECT also revealed hypoperfusion in the cerebellar vermis, which had recovered by the follow-up examination. Three patients showed saccadic hypermetria or impaired smooth pursuit only during the acute phase.ConclusionsOur patients with TGA showed cerebellar vermian hypoperfusion in addition to ischemic insults to the lateral hippocampus. The oculomotor abnormalities observed in our patients support the occurrence of cerebellar dysfunction during the TGA attack.

Transient global amnesia during transoesophageal echocardiogram

Transient global amnesia (TGA) is a common paroxysmal disorder of episodic memory. The aetiology of TGA is still unknown. Brain ischaemia, migraine, epileptic seizure, venous congestion and psychological disturbances have been proposed as pathological mechanisms. Moreover, different precipitating events are recognised in most TGA patients including physical activity, severe emotional stress, painful experiences, immersion in cold water and sexual intercourse. We describe a 54-year-old woman who presented a TGA immediately after right-left shunt of saline contrast during the execution of transoesophageal echocardiography. Aetiopathological considerations for this uncommon presentation are discussed.

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is not significantly correlated to Transient Global Amnesia: Preliminary results of an on-going study in Brescia Province, Italy

Transient Global Amnesia (TGA) is a well defined pure amnesic clinical syndrome characterized by acute loss of memory in middle aged people. The aetiology of TGA is still unknown but clinical and neuroimaging studies support a hippocampi involvement, and some reports suggested a possible common genetic background in cases of familial TGA. A single nucleotide polymorphism (SNP) in the Brain-derived neurotrophic factor (BDNF) gene that causes a valine to methionine substitution at codon 66 (Val66Met) has been demonstrated to affect human memory and hippocampal function in the development and maintenance of adult neurons. Aim of this study was to evaluate the role of BDNF Val66Met polymorphism on TGA risk and all TGA clinical features. Ninety-eight TGA patients and 93 age-matched controls were enrolled in the study. Each patient underwent clinical and neurological examination, routine blood examination, EEG, Jugular vein valve (JVI) competence assessment, and neuroimaging study. TGA characteristics were carefully recorded. The distribution of BDNF genotype did not differ in TGA patients compared to controls (BDNF GG: 58.2% vs 55.9%, GA: 33.7% vs 36.6%, AA: 8.1% vs 7.5%, P=.91) as well as allele frequency (BDNF G, TGA vs CON: 75.0% vs 74.2, P=.47). No significant differences in age at onset, disease duration and recurrence or the presence of predisposing factors between TGA patients carrying BDNF AA, BDNF GA and BDNF GG genotype were found. This study, that firstly looked at genetic background in TGA, did not show a significant correlation between the BDNF Val66Met polymorphism and age of onset, risk factors, duration or recurrence of TGA.

Amnesia global transitoria: una revisión. I. Aspectos clínicos

Transient global amnesia (TGA) is a neuropsychological syndrome in which a sudden, temporary loss of the capacity of creating new memories and a retrograde amnesia of variable intensity occur, whereas consciousness, personal identity and attention are preserved. To review different clinical aspects about TGA. Accordingly, the following topics will be reviewed: definition and diagnosis criteria, types of amnesias which should be ruled out and their peculiarities and differences with TGA, epidemiological data such as incidence, age, sex, educational level of the patients and number of TGA episodes, most frequent scene where TGA appears, and most common triggering events. Additionally, classical proposals about its possible etiology (epilepsy, vascular disease and migraine) and other new theories (Leao's spreading depression or influence of stress) will be revised. Finally, different data about neuroimaging studies in patients with TGA will be reviewed. There are data and arguments in favour and against the hypotheses regarding etiology of TGA, but there is no current consensus on a theory which explains in a satisfactory way the nature of this kind of amnesia.

Weather conditions and transient global amnesia

The aetiology of transient global amnesia (TGA) is still unknown. Various events or activities have been shown to trigger TGA. A common feature of these events is an increased sympathetic activity which in turn may be influenced by meteorological factors. This prompted us to evaluate the influence of climatic parameters, and their variation on the incidence of TGA. A total of 223 cases of TGA admitted to our hospital over a six-year period were studied. The study consisted of a comparison between the climatic parameters of days with TGA and those without TGA. The meteorological database included daily values of parameters recorded at the meteorological station of the town during this period. The onset of TGA was significantly correlated with lower daily,monthly and seasonal temperature values. Most cases of TGA were found when the temperature was less than 6.9 degrees C,whereas the frequency of TGA was minimum when it was more than 24 degrees C (P < 0.0001). Only temperature had a significant independent effect: an increase of 1 sd = 8.4 degrees C decreases the TGA admission odds of 0.78 (95 % CI: 0.62 to 0.97), i.e -22% (95 % CI: -38% to -3 %). This study suggests an association between TGA occurrence and low ambient temperature. Multicentre studies taking into account climatic differences between countries are necessary to confirm our findings.