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PubMed1994

Paraneoplastic temporal lobe epilepsy with testicular neoplasm and atypical amnesia.

We report a patient who, at age 38, presented with temporal lobe seizures and an atypical memory disorder 3 years before the discovery of a testicular tumor. Detailed neuropsychological testing revealed a relatively isolated amnestic syndrome. The amnesia was atypical as the patient could retain information for hour-long periods, only to lose it later. Serologic studies revealed the presence of a circulating autoantibody that demonstrated an unusual affinity for the nucleolus of cerebral cortical neurons. Western blot analysis of cortical neurons revealed that this antibody reacted with proteins different from other previously identified paraneoplastic neurologic antigens (Hu, Yo, Ri). We believe this to be a case of paraneoplastic limbic encephalitis secondary to the testicular tumor. This patient presents unique characteristics with respect to the mode of presentation, features of the amnesia, and the presence of a circulating antibody with an unusual reactivity pattern.

Amnesia↗
PubMed1995

Amnesia following traumatic bilateral fornix transection.

There is controversy regarding the effect of isolated fornix damage on human memory. We report a patient who suffered a traumatic penetrating head injury that resulted in a significant and persistent anterograde amnesia. CT revealed a lesion that involved the region of the proximal, posterior portion of both fornices without evidence of damage to other hippocampal pathways or to other structures known to be critical for memory, such as the hippocampus, thalamus, or basal forebrain. The unique location of the lesion in this patient provides evidence supporting the role of isolated fornix lesions in amnesia.

Adult↗
PubMed1996

Failure to recall (but not to remember): pure transient amnesia during nonconvulsive status epilepticus.

We report a patient with a generalized frontal-predominant nonconvulsive status epilepticus without clinically apparent altered consciousness. The patient was examined and EEG performed during and after the episode. Severe retrograde and anterograde amnesia during the seizure, contrasting with a preservation of ongoing memories formation that could be assessed only after its resolution, suggests a transient disconnection of access to stored representations. This unusual memory disorder is both clinically and electrographically dissimilar to other reported cases of transient epileptic amnesia. Although the patient probably had numerous episodes previously, there was no history of overt seizure.

Adult↗
PubMed1998

Transient autobiographic amnesia: EEG and single-photon emission CT evidence of an organic etiology.

We describe a 44-year-old patient who had a transient attack of autobiographic amnesia. When assessed during the attack, her learning abilities were normal, with no sign of anterograde amnesia. In the remote memory domain, she showed a striking dissociation between a detailed knowledge of public events and famous people and a complete loss of autobiographic information. During the attack, EEG recorded bilateral frontotemporal slow waves and single-photon emission CT (SPECT) showed hypoperfusion in the right temporal and parietal lobes; no abnormalities were detected when both EEG and SPECT were repeated 1 week later. This case provides evidence for an organic etiology for the episode and supports the hypothesis that autobiographic memory is independent of other forms of retrograde memory.

Adult↗
PubMed1984

Evoked potential correlates of posttraumatic amnesia after closed head injury.

The P-300 component of evoked potentials to a rare tone was measured in normal volunteers and in patients with closed head injuries who either were confused (in posttraumatic amnesia) or had recovered from posttraumatic amnesia and were oriented at the time of recording. The latency of this component, which reflects cortical processing of stimuli, varied reliably, with the degree of orientation being longest for confused patients and shortest for normal subjects. On the basis of these data, we suggest that the P-300 latency can be used as a physiological index of cognitive function in patients with closed head injury.

Adolescent↗
PubMed1987

[Pharmacological studies on Y-8894. (VII). Effects on transient cerebral ischemia-induced amnesia in rats].

The effects of Y-8894 on experimental amnesia in rats induced by transient cerebral ischemia (600 sec) according to the method of Pulsinelli and Brierley were studied using the one trial passive avoidance response and the pole climbing discrete avoidance response. All drugs were administered to the rats immediately after recirculation. The following results were obtained: 1) In the one trial passive avoidance response test, Y-8894 (2.5, 5 and 10 mg/kg, i.p.) improved significantly the decreased latency induced by the ischemia, and it was most effective at 5 mg/kg. Calcium-hopantenate (100, 250 and 500 mg/kg, i.p.) and dihydroergotoxine (5 and 10 mg/kg, i.p.) tended to increase the latency. On the other hand, physostigmine (0.025, 0.05 and 0.1 mg/kg, i.p.), a cholinesterase inhibitor, increased the latency significantly, and it was most effective at 0.05 mg/kg. 2) The pole climbing discrete avoidance response was significantly decreased by the ischemia compared with the sham operated group, and Y-8894 (5 mg/kg, i.p.) tended to improve this decreased avoidance response. 3) Y-8894 (5 mg/kg, i.p.) facilitated recovery from the changes in glycolytic metabolism, and inhibited the accumulation of choline due to the dysfunction of the neuronal membranes induced by the ischemia. These results show that Y-8894 has beneficial effects on experimental amnesia induced by transient cerebral ischemia.

Amnesia↗
PubMed1988

Amelioration of experimental amnesia (passive avoidance failure) in rodents by the selective M1 agonist AF102B.

Effect of AF102B (cis-2-methylspiro-(1,3-oxathiolane-5,3')-quinuclidine) on experimental amnesia was examined using a passive avoidance task in rodents. The amnesia was produced by anti-cholinergic agents, AF64A (intracerebroventricularly) and scopolamine (subcutaneously). AF102B ameliorated the memory deficits in AF64A-treated rats at 0.1-1 mg/kg, i.p. and at 1-5 mg/kg p.o. and in scopolamine-treated mice at 1-10 mg/kg, i.p. These results suggest that AF102B may compensate for central cholinergic defects and could be developed as a possible therapeutic drug for senile dementia of the Alzheimer type.

Amnesia↗
PubMed2006

Memory-enhancing effect of a supercritical carbon dioxide fluid extract of the needles of Abies koreana on scopolamine-induced amnesia in mice.

Abies koreana Wilson (A. koreana) is a shrub or broadly pyramidal evergreen tree endemic in the mountainous regions of South Korea. We obtained the essential oil (EO) from alpine needle leaves of A. koreana by the supercritical fluid extraction (SFE) method. EO was analyzed by gas chromatography-mass spectrometry (GC-MS), and 68 compounds were identified constituting 95.66% of the oil. The major components were elemol (11.17%), terpinen-4-ol (9.77%), sabinene (8.86%), 10(15)-cadien-4-ol (7.16%), alpha-terpineol (6.13%), alpha-pinene (6.07%) and gamma-terpinene (4.71%). To investigate the memory-enhancing effects, we conducted a passive avoidance test using a scopolamine (1 mg/kg, ip)-induced amnesia mouse model. A peritoneal injection of EO from A. koreana (100 mg/kg) showed a memory enhancing effect of 72.7% compared with the control. These results suggest that EO of A. koreana may be a useful therapeutic agent against such amnesia-inducing diseases as Alzheimer and vascular dementia.

Abies↗
PubMed2006

Daidzein activates choline acetyltransferase from MC-IXC cells and improves drug-induced amnesia.

The choline acetyltransferase (ChAT) activator, which enhances cholinergic transmission via an augmentation of the enzymatic production of acetylcholine (ACh), is an important factor in the treatment of Alzheimer's disease (AD). Methanolic extracts from Pueraria thunbergiana exhibited an activation effect (46%) on ChAT in vitro. Via the sequential isolation of Pueraria thunbergiana, the active component was ultimately identified as daidzein (4',7-dihydroxy-isoflavone). In order to investigate the effects of daidzein from Pueraria thunbergiana on scopolamine-induced impairments of learning and memory, we conducted a series of in vivo tests. Administration of daidzein (4.5 mg/kg body weight) to mice was shown significantly to reverse scopolamine-induced amnesia, according to the results of a Y-maze test. Injections of scopolamine into mice resulted in impaired performance on Y-maze tests (a 37% decreases in alternation behavior). By way of contrast, mice treated with daidzein prior to the scopolamine injections were noticeably protected from this performance impairment (an approximately 12%-21% decrease in alternation behavior). These results indicate that daidzein might play a role in acetylcholine biosynthesis as a ChAT activator, and that it also ameliorates scopolamine-induced amnesia.

Amnesia↗
PubMed2006

The long and the short of it: relational memory impairments in amnesia, even at short lags.

Classic studies of amnesia led to characterizations of hippocampal function emphasizing involvement in long-term memory rather than short-term (or working) memory. In two experiments, we show that when memory for relations among co-occurring items is tested, hippocampal amnesia results in a deficit even at very short lags. Hence, we find evidence for hippocampal involvement in relational memory, even at short lags normally considered the province of working memory.

Amnesia↗
PubMed1998

Amnesia during cold water immersion: a case report.

This report describes a case of amnesia during a cold-water experiment. The volunteer was exposed three times in 1 day (120 min duration each time) to 20 degrees C water. During the third immersion, from min 95 to min 115, the subject experienced transient global amnesia for 20 min. The rectal temperature during this time was 35.6 degrees C. This single case demonstrates that memory loss in a young individual apparently can occur after cold-water exposure and at core temperatures above 35 degrees C.

Adult↗
PubMed2000

High-altitude global amnesia.

A variety of transient focal neurological signs presenting at high altitude have been described without associated acute mountain sickness or other concurrent illness. We report a case series of transient global amnesia at high altitude. The term high-altitude global amnesia (HAGA) is introduced to indicate this condition, and the pathophysiology is discussed. We hypothesize that because of the highly variable ventilatory response to hypoxia and to individual cerebral vasomotor reactivity, individuals with a marked hyperventilatory response could experience significant hypocapnic cerebral vasoconstriction that in turn could cause local hypoxia or ischemia to particular regions of the brain and resulting transient focal neurological impairment.

Adult↗
PubMed1991

Severe amnesia after hypoglycemia. Clinical, psychometric, and magnetic resonance imaging correlations.

OBJECTIVE: To determine the correlation between clinical, psychometric, and magnetic resonance imaging (MRI) findings after an episode of hypoglycemic coma resulting in amnesia. RESEARCH DESIGN AND METHODS: Detailed psychometric assessment, especially memory testing, performed with MRI in a man with severe amnesia after hypoglycemic coma. RESULTS: Psychometric testing confirmed impaired immediate recall. MRI findings were consistent with a lesion in the left temporal lobe. CONCLUSIONS: This is the first description of MRI in determining the neurological damage in hypoglycemic coma.

Adult↗
PubMed1994

"Experimental amnesia" induced by emotional items.

Tulving described an effect of retrograde amnesia in a free-recall task of word lists, produced by inserting items having priority in recall. Other authors confirmed the amnesic effect without giving instructions for priority both in recall and in recognition tasks. The effect was explained by Tulving as a premature termination of encoding processes. The similarity between these experiments and the researches aimed at reproducing amnesia by emotional trauma led us to hypothesize that the two phenomena might be due to the same functional mechanisms. We have organized a free-recall task of word lists into which emotional items were inserted. Our aim was to verify whether with these experimental conditions Tulving's results would be reproduced. The obtained data show amnesic effects in free recall; nevertheless, they do not seem to confirm closely the experimental hypothesis. Lastly, changes in primacy and recency effects produced by emotional items are analyzed.

Adult↗
PubMed1996

Transient global amnesia and dural arteriovenous fistula of the anterior cranial fossa.

Dural arteriovenous fistula (AVF) of the anterior cranial fossa is associated usually with cerebral hemorrhage or subarachnoid hemorrhage, while an association with transient global amnesia has not been reported previously. A case presenting the latter unusual symptom is described and the surgical treatment of AVF is discussed. A 64-year-old woman was hospitalized complaining of transient memory impairment. Magnetic resonance (MR) imaging demonstrated a flow void in the left frontal lobe and temporal pole. Cerebral angiography revealed an AVF in the anterior cranial fossa, which was fed bilaterally by the ethmoidal arteries and by branches of the external carotid arteries. The AVF drained into the superior sagittal sinus and the superficial sylvian vein via large varices. Following transfemoral embolization, surgical treatment was carried out. Postoperative angiography revealed complete obliteration of the anomaly. There were no further episodes of amnesia. In our presented case, there is an association between the presenting symptoms and the AVF. The combination of ischemia and congestion in the frontal and temporal lobes may have caused transient memory impairment. From our surgical experience, the excision of the vascular connection between the dura and the frontal lobe following the coagulation of the dura mater of the anterior part of the base of the skull without extensive excision seems to be recommended.

Acute Disease↗
PubMed1993

Generalised dissociative amnesia.

A case of generalised dissociative amnesia is presented, which illustrates several characteristic features of this uncommon condition. The case showed poor response to thiopentone interviews and in vivo cueing. Amnesia had persisted at six months follow up.

Adult↗
PubMedDate not supplied

Learning in post-traumatic amnesia following extremely severe closed head injury.

Verbal and spatial tests of learning were administered in five repeated sessions to nine subjects who were in post-traumatic amnesia (PTA) following extremely severe closed head injuries. PTA was operationally defined as having a score of 75 or less on the Galveston Orientation and Amnesia Test. Subjects showed no ability to learn verbal information (free recall and recognition of a word list) but showed some savings of spatial location information over the first three sessions. Results were interpreted as suggestive of a primarily passive mode of learning during PTA, regardless of the nature of the material to be learned.

Adult↗