BACKGROUND: The dot-like hippocampal signal intensity in diffusion-weighted MR images is well-known as a characteristic imaging feature in transient global amnesia, a neurological syndrome in which sudden forward-and-backward memory loss occurs that is slowly recovered within 24 hours. We here report on patients with this dot-like hippocampal hyperintensity who did not present with anterograde amnesia except for headaches. CASE REPORT: Two women without a specific medical history presented with sudden-onset headaches on the same day. Neither had any trauma or infection history before the symptom or any sudden emotional or postural changes. Brain MRI showed tiny hippocampal high signal intensity on diffusion-weighted images (DWI). CONCLUSIONS: Dot-like hippocampal lesions seen on DWI may be present without memory impairment, and more studies are needed to determine whether there is any association with headache as in this case.
Amnesia, Anterograde ; Amnesia, Transient Global* ; Brain ; Diffusion* ; Female ; Headache* ; Hippocampus ; Humans ; Magnetic Resonance Imaging ; Memory ; Memory Disorders

Cases showing memory disturbances with isolated retrograde memory without any definitive brain lesions are classified as dissociative amnesia. Improvements in imaging techniques have allowed the organic causes of this disease to be identified in several recent cases. Several studies have diagnosed cases of memory disorders as pure retrograde amnesia (PRA). The patient reported here had no psychiatric disorder and had normal MRI results, but showed hypometabolism in PET that met the criteria for PRA.
Amnesia ; Amnesia, Retrograde ; Brain ; Humans ; Memory ; Memory Disorders

We report two patients who complained of transient anterograde amnesia and repetitive questioning, that developed after taking zolpidem and lasted for several hours. The clinical manifestations of these patients fulfill the clinical criteria for transient global amnesia (TGA). The typical clinical manifestation of TGA following the consumption of zolpidem suggests a possible relationship associated with its drug mechanism.
Amnesia, Anterograde ; Amnesia, Transient Global ; Humans

Transient global amnesia(TGA) is not a rare event in the elderly, which is characterized by transient inability to form the new memory traces plus retrograde amnesia with benign prognosis. The etiology is unknown, but suggested causes have included transient ischemic attack, migraine, epilepsy, brain tumor, drug intoxication, other toxic/metabolic disturbances, or hysteria. Especially, TGA associated with ischemic stroke is important on the elderly patients and necessary to be differentiated with other causes, for stroke prevention. As far as we know, the case of TGA due to cerebral infarction confirmed by brain imaging study is extremely rare in the literature. We report the case of 67 year-old female patient with typical TGA showing ischemic lesion on the right temporal area on MRI and discussed its significance as one of the cause of TGA.
Aged ; Amnesia, Retrograde ; Amnesia, Transient Global* ; Brain Neoplasms ; Cerebral Infarction ; Epilepsy ; Female ; Humans ; Hysteria ; Infarction* ; Ischemic Attack, Transient ; Magnetic Resonance Imaging ; Memory ; Migraine Disorders ; Neuroimaging ; Prognosis ; Stroke

We report a case of profound amnesia, anterograde and retrograde, in a patient, who had been premedicated with midazolam and underwent a posterior fusion of the cervical spine under inhalation anesthesia. The patient's memory was restored immediately after intravenous injections of the benzodiazepine antagonist flumazenil.
Amnesia ; Amnesia, Anterograde ; Amnesia, Retrograde* ; Anesthesia, Inhalation ; Benzodiazepines ; Flumazenil* ; Humans ; Injections, Intravenous ; Memory ; Midazolam* ; Spine

Transient global amnesia is characterized by a sudden memory loss of recent and/or remote events and transient inability to acquire new knowledge. Although mostly followed by complete recovery within a day, this rare and unexpected event in recovery phase after general anesthesia should be embarrassing and confusing, so we must proceed with prompt differential diagnosis for other organic intracranial pathology including transient ischemic attack and go on close observation. We describe a case of transient global amnesia of a 66-year-old woman after general anesthesia for excision and biopsy of left neck mass.
Aged ; Amnesia ; Amnesia, Transient Global ; Anesthesia, General ; Biopsy ; Diagnosis, Differential ; Female ; Humans ; Ischemic Attack, Transient ; Memory Disorders ; Neck

Dot-like hippocampal hyperintensities on diffusion-weighted magnetic resonance imaging (MRI) have been reported as an interesting imaging finding of transient global amnesia (TGA). We report three patients with such dot-like hippocampal hyperintensities who did not present with anterograde amnesia. Episodes associated with the Valsalva maneuver such as nausea or vomiting might have produced the dot-like hippocampal hyperintensities in these patients. However, depending on the individual susceptibility to hippocampal lesions, clinical symptoms of TGA might not be present even when hippocampal lesions are present.
Amnesia, Anterograde ; Amnesia, Transient Global* ; Hippocampus ; Humans ; Magnetic Resonance Imaging* ; Nausea ; Valsalva Maneuver ; Vomiting

Background and purpose: Transient global amnesia (TGA) is a rare amnestic syndrome characterized by the sudden onset of a selective anterograde and retrograde amnesia with a time course of up to 24 hours. Recent studies have found a high frequency of small high-signal abnormalities in the hippocampus on diffusion-weighted imaging (DWI), and accordingly ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, which is known to be susceptible to ischemia. Methods: Twenty consecutive patients with a clinical diagnosis of TGA underwent DWI both within 24 hours of symptom onset and 3 days later. Twenty patients with high-signal abnormalities in the hippocampus on the initial DWI underwent subsequent DWI and T2-weighted imaging in the coronal plane to precisely localize the lesions. Results: Seventeen patients had small high-signal abnormalities (with diameters of 1-3 mm) in the hippocampus unilaterally on DWI. One of these patients had two lesions in one hippocampus. Three of the 20 patients had lesions bilaterally in the hippocampus, 1 of whom had 3 bilateral lesions. A total of 25 lesions were identified: 5 in the hippocampal head, 19 in the body, and 1 in the tail. Six patients had unilateral lesions on the left,11 patients had them on the right, and 3 patients had bilateral lesions. Conclusions: In this study, lesions associated with TGA were localized mostly to the lateral portion of the hippocampus, corresponding to CA1. This finding supports the ischemic etiology of TGA, but the underlying pathophysiologic mechanism requires further investigation.
Amnesia, Retrograde ; Amnesia, Transient Global ; Head ; Hippocampus ; Humans ; Ischemia

Transient global amnesia (TGA) is an amnesic disorder which is characterized by temporary loss of anterograde and recent retrograde memory with preserved consciousness. Though the pathogenesis of TGA is still unclear, current hypotheses include migraine, seizure, or cerebral ischemia. We present three patients with TGA who showed signal intensity change in diffusion weighted image in hippocampus. These findings might suggest that ischemia in hippocampus might be the cause of the TGA.
Amnesia, Transient Global* ; Brain Ischemia ; Consciousness ; Diffusion* ; Hippocampus* ; Humans ; Ischemia ; Memory ; Migraine Disorders ; Seizures

BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is a stereotypic condition characterized by anterograde and retrograde amnesia that typically resolves within 24 hours. The pathophysiology of TGA is still unclear. We noted that patients hospitalized with TGA tend to appear in seasonal clusters, and decided to investigate this phenomenon. METHODS: Every patient with acute presentation of amnesia at our medical center is hospitalized for observation and evaluation. We reviewed the monthly occurrence of TGA in our patient population between 2000 and 2014, and compared this to non-TGA hospitalizations during the same time period. RESULTS: During the analysis period, 154 patients who met the criteria for TGA were hospitalized, as well as 259,007 non-TGA hospitalizations. The annual occurrence of TGA ranged from 5 to 16 hospitalizations. There were 91 TGA events in women and 63 in men, in subjects aged 62.8±10.6 years (mean±SD). The incidence was maximal during December [odds ratio (OR)=2.83, 95% confidence interval (CI)=1.20–6.67] and March (OR=2.77, 95% CI=1.17–6.56), and minimal from April to August. The incidence exhibited an increase followed by a decrease from October to February. A seasonal trend was observed as well, with incidence peaks occurring in winter (OR=1.82, 95% CI=1.12–2.96) and spring (OR=1.80, 95% CI=1.10–2.94). CONCLUSIONS: Our findings suggest that the incidence of TGA exhibits seasonal variations. This observation may help to improve the understanding of the pathophysiology underlying TGA.
Amnesia ; Amnesia, Retrograde ; Amnesia, Transient Global* ; Female ; Hospitalization ; Humans ; Incidence* ; Male ; Seasons*