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PubMed1999

Transient global amnesia: a retrospective study of 25 patients.

BACKGROUND: Transient global amnesia (TGA) is a syndrome characterized by an abrupt onset of severe anterograde amnesia and variable retrograde amnesia, usually accompanied by repetitive query during the attack. Its etiology is unknown. METHODS: We retrospectively studied patients who were admitted to National Cheng Kung University Hospital during, or just after, their first transient amnesic episode between July, 1988, and December, 1997. We examined the details of the attacks, including time of onset, duration, activities upon onset, potential precipitating factors, behavior during attack, and accompanying neurologic signs or symptoms. We also inquired about past medical history, current status and recurrence. RESULTS: Twenty-five patients, 11 men and 14 women met the criteria for TGA. Their ages ranged from 27 to 77 years (mean, 60 years). The length of an attack ranged from one to 11.5 hours (mean, 6.3 hours). Nineteen attacks occurred in the morning and 10 had precipitating factors. The significant past history included hypertension, cardiovascular disease, migraine headache and thyroid disorders. None of the patients had a family history of TGA. Investigation revealed abnormal cerebral computerized tomographic (CT) scans or magnetic resonance images in three patients (12%), abnormal cerebral single photon emission CT (SPECT) in six (86%) of seven performed within the first eight days, and abnormal electroencephalography (EEG) in five patients (24%). The left temporal region was the most common site of dysfunction shown by EEG and cerebral SPECT. Three (12%) patients experienced a recurrent attack. CONCLUSIONS: Our patients had a higher rate of thyroid disorders, and most had their amnesia attacks in the morning. As compared with previously published studies, the results showed no differences with respect to age, duration of behaviour during attack, EEG, CT, family history and recurrence rate. The exact duration of an attack is sometimes difficult to estimate. Moreover, the increasing case numbers over the years indicates the importance of the need for better education of medical residents regarding TGA.

Adult↗

PubMed2004

[Alcohol-related amnesia ("blackout") in broader perspective].

Alcohol-related amnesia ("blackout") is a common even in people who are not alcohol dependent. The average duration of simple alcohol-induced amnesia in our alcohol dependent male patients was almost 8 hours (7.96, SD=23.96). Alcohol-induced amnesia is considered to be a risk factor for long-term impairment of cognitive functions, if alcohol abuse continues. On the other hand cognitive functions in alcohol dependent persons who abstain from alcohol often improve remarkably because of reorganisation and restoration of neuronal networks. This process can be enhanced by vitamin B1, appropriate treatment of withdrawal syndrome, memory training, coping with stress and depression (relaxation techniques can be used), balanced life-style, and nootropic drugs. Alcohol-related amnesia often motivates alcohol dependent patients to overcome their problem, especially if it is appropriately used in psychotherapy.

Adult↗

PubMed1991

Midazolam and amnesia in pediatric premedication.

One hundred and twenty-eight children aged three to ten years, were studied to determine the effect of premedication on amnesia for the preanesthetic period. Four comparable groups were used: A control group, no premedication; oral trimeprazine tartrate 2 mg/kg, methadone 0.1 mg/kg plus droperidol 0.15 mg/kg (T.M.D.); oral midazolam 0.45 mg/kg; intramuscular midazolam 0.15 mg/kg. Amnesia was tested for four pictorial facts, and for induction of anesthesia. For pictorial facts, both routes of midazolam administration gave a sixty percent incidence of amnesia compared with sixteen percent in the control group (p less than 0.001). The T.M.D. premedication provided a forty-three percent incidence, also better than the control group (p less than 0.05). Induction was remembered by fifty percent of the midazolam children compared with sixty-six percent of the T.M.D. group (p greater than 0.05) and eight-one percent of the control group (p less than 0.05). The potential advantages of amnesia in pediatric premedication are discussed.

Administration, Oral↗

PubMed1991

[An effect of priming task repetition on memory processes in an epileptic with amnesia].

The purpose of this paper is to investigate memory processes in an epileptic with amnesia. Selective impairment of memory in organic amnesia has been reported in some clinical observations. They also demonstrated that organic amnesia can retain some aspects of learning experience, despite their inability to recollect them. We investigated an effect of priming task repetition on memory processes in a female with organic amnesia aged 28 (probable encephalitic patient) and eight control college students aged 20-26. In this paper, her memory processes were analyzed, using the same picture priming task, carried twelve times during the period of seven months. We used semantic priming paradigm. Three types of prime-target pair were used: identical, semantically related and unrelated. After a prime picture, a target picture appeared on the CRT display. She was asked to name each target as rapidly and accurately as possible. We analysed reaction time (RT) in naming the picture targets, error rate, and verbal reports of the priming task in the pre- and post-examination interview. In the first examination, priming effect was observed in her RT as in the controls'. This suggests that she retained some amount of semantic memory, and the structure of her semantic memory closely resembled that in the controls. Naming RT reduced and error rate decreased with repetition of the examination. This suggests that she acquired picture naming skill during early few examinations. However it was difficult for her to recognize and recollect the picture stimuli in this period. Further, she did not show any episodic memory of the examinations. There was dissociation between improved RT performance and poor verbal reports during early few examinations. When the same priming task was repeated in early few examinations, the priming effect became weaker in her RT. In the controls, on the contrary, the priming effect remained during the whole task repetition. Semantic strategy was apparently used in the controls, but not in the amnesic patient. She apparently used strategy of non-semantic association between the prime and target. In the last few examinations, her naming RT delayed and the priming effect was observed again as in the first examination. She seemed to use semantic strategy. In addition to this priming effect, she re-collected a few pictures and showed some episodic memory of the examination.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1990

[Recovery, amnesia and affective state following propofol in comparison with thiopental].

Numerous reports have described a definite sense of well-being after anesthesia with propofol (Disoprivan). The present study was designed to assess postoperative mood as recorded with a quantitative self-rating method. Postoperative recovery and amnesia were also investigated. Thirty unpremedicated female patients aged 20-60 (ASA grade 1 or 2) who were scheduled for minor gynecological operations were enrolled in the study after informed consent. The patients were randomly allocated to three study groups: group A, induction with propofol 2 mg/kg and maintenance with propofol 0.15 mg/kg per min together with N2O/O2; group B, induction with propofol 2 mg/kg and maintenance with enfluran and N2O/O2; group C, induction with thiopental until loss of the eye lash reflex and maintenance with enfluran and N2O/O2. Postoperative amnesia was assessed by showing five picture cards at 5-min intervals, starting when the patients were able to state the correct date of birth. A test of recovery (p-deletion) was carried out after 30 and again after 60 min. The postoperative mood state was evaluated with the adjective checklist of Janke and Debus 5 h after waking. In good agreement with published reports, propofol patients recovered more rapidly than thiopental patients. A significant but irrelevant amnesia occurred after 5 min in group B. However, in some cases amnesia lasting up to 20 min was observed. The global mood status showed a significantly higher score for positive items and a lower score for negative items after propofol administered by either technique than after thiopental (P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Bupropion activation of memory trace retrieval in amnesia and forgetting].

The effect of a new antidepressant bupropion on the processes of retrieval of the conditioned response of passive avoidance in mice under amnesia of different genesis and spontaneous forgetting was studied. The drug was shown to exert the antiamnesic effect and to facilitate retrieval of amnesia-affected or forgotten memory trace. The maximal effect of bupropion was observed at the dosage of 30 mg/kg. At the use of bupropion on the 2nd day after exertion of amnesic influences there was registered the tendency to prolongation of preservation of the conditioned habit enhanced retrieval as compared with greater time periods. The drug effect under memory trace retrieval impaired by cycloheximide-induced amnesia was similar in the action but more pronounced than that under "psychogenic" amnesia. The data obtained testify in favour of an active involvement of the brain dopaminergic system in the processes of memory trace retrieval.

Amnesia↗

PubMedDate not supplied

Amnesia after femorocerebral angiography.

The charts and radiographs of 12 of 1,520 patients who developed amnesia after transfemoral cerebral angiography performed with local anesthesia and minimal sedation were retrospectively reviewed. In three younger patients, exacerbation of organic or idiopathic temporal lobe epilepsy was thought to be the cause of the amnesia, while the amnesia of the nine patients over 40 years old had the characteristics of transient global amnesia. Eight of the patients had had similar episodes before angiography, and three others had other evidence of vertebrobasilar disease. Emboli from atheromatous debris or catheter clot due either to catheter manipulation problems, an inexperienced operator, or the use of a large catheter were considered likely causes in 11 cases, while in three patients contrast emboli or toxicity may have been the etiologic factor.

Adult↗

PubMed1984

[Cerebral angiography in transitory global amnesia].

33 patients with transient global amnesia were examined by cerebral angiography. The presence of arterial lesions correlated with neurological symptoms, as well as with amnesia. In 55% of cases no pathological alterations were found, so that the pathogenesis of the transient global amnesia remained unclear. For clinical purposes, cerebral angiography is recommended only in those cases which show other neurological symptoms besides the transient global amnesia.

Adult↗

PubMed1994

[Pure anterograde amnesia due to bilateral fornix lesions].

The patient was a right-handed 59-year-old female technician who was admitted to our hospital with a complaint of memory loss. Clinical examination revealed pure anterograde amnesia regarding episodic memory, while semantic and procedural memory was intact. Radiological procedures (CT scan and MRI) revealed a tumor of the septum pellucidum, which localized from the lower part of the corpus callosum to the anterior parts of the bilateral fornices. Transcallosal total removal was performed (pathological examination revealed that it was astrocytoma). Radiological and operative findings showed that the thalamus, the mammillary bodies, the hippocampus, and the basal forebrain, which are closely related to memory, were spared. After the operation, she reported no further memory disturbance. Preoperative neuropsychological tests revealed anterograde amnesia for verbal and visual stimuli, but postoperatively the former disappeared and the latter improved. Pre- and postoperatively, she was nonaphasic, and her immediate memory, intelligence, and frontal functions were intact. Cases of amnesia due only to fornix lesions are rare, and have not been reported yet in Japan. Our case is valuable in terms of showing that only the fornix lesion was responsible for memory disturbance. The main symptom resulting from fornix lesion is thought to be anterograde amnesia.

Amnesia, Retrograde↗

PubMed1997

[Prolonged antegrade amnesia due to left anterior thalamic infarct, and SPECT findings].

A 60-year-old right-handed man developed disorientation, antegrade amnesia and transient mild clouding of consciousness. The antegrade amnesia persisted for more than one year after its onset. T2-weighted MR images showed high signal intensity in the left anteromedial thalamus. 99mTc-HM-PAO SPECT revealed decreased uptake in the left frontal and temporal lobes. These SPECT findings were still observed a year later. These findings suggest that functional involvement of the frontal and temporal lobe connections with the dorsomedial nucleus, anterior nucleus, and the mamillothalamic tract in the anteromedial part of thalamus were responsible for the prolonged antegrade amnesia. We think that SPECT findings are important for evaluating the outcome of thalamic amnesia.

Amnesia↗

PubMed1997

Pretest administration of glucose attenuates infantile amnesia for passive avoidance conditioning in rats.

Infantile amnesia in rats may be attenuated by a wide variety of retrieval cues which reactivate memory for the training episode. The present study investigated the effects of glucose on memory retrieval in infant rats. In Experiment 1, 17-day-old preweanling rats were trained to criterion on passive avoidance conditioning. Twenty-four hours later, each subject received a subcutaneous injection of either saline, 100 mg/kg, or 250 mg/kg of glucose just prior to testing. Saline animals displayed poor retention scores, suggesting infantile amnesia; however, glucose significantly attenuated the 24-hr retention loss. Experiment 2 attempted to replicate the previous experiment, control for age and general drug effects, and extend the dose of glucose to 400 mg/kg. The results of Experiment 2 were consistent with Experiment 1 and also indicated that infant subjects performed significantly worse than adults. Both 100 and 250 mg/kg of glucose significantly attenuated infantile amnesia; however, 400 mg/kg had no effect. These results support a retrieval failure view of infantile amnesia and extend the memory-influencing properties of glucose to infants. Context and neuroendocrine views of memory retrieval are discussed.

Age Factors↗

PubMed1983

Attenuation of experimental retrograde amnesia through pretraining administration of a dissimilar amnestic agent.

Experiment 1 found that pretraining administration of electroconvulsive shock (ECS) attenuated ECS-induced amnesia of one-trial passive avoidance training in rats. Similarly, pretraining injections of cycloheximide (CXM) attenuated the amnestic effects of CXM at training. Experiment 2 demonstrated the ability of pretraining ECS to attenuate CXM-induced amnesia and pretraining CXM to attenuate ECS-induced amnesia. These studies join others in observing comparable behavioral effects of ECS-like amnestic agents and antimetabolite-like amnestic agents despite their different means of primary action. Collectively, these studies support the view that the two families of amnestic agents produce amnesia through a common mechanism.

Animals↗

PubMed1993

Time gradient for post-test vulnerability to scopolamine-induced amnesia following the initial acquisition session of a spatial reference memory task in mice.

The time course for vulnerability to the amnestic effects of the cholinergic antagonist, scopolamine, during the postacquisition period has been investigated. We have examined the effects of post-test injections of scopolamine (1 mg/kg ip) given at different times from 30 s for up to 6 h following the end of the first acquisition session of a concurrent spatial discrimination (reference memory) protocol in an 8-arm radial maze on subsequent long-term (24 h) retention performance in C57BL/6 mice. Results show that the immediate (30 s) post-test injection of scopolamine-HCl on Day 1 produces marked perturbation (amnesia) of long-term retention as attested to by significant deficits in various indices of spatial discrimination performance gain on Day 2 as compared to control subjects injected either with scopolamine-MBr or saline. The severity of this scopolamine-induced amnesia declines only slightly as a function of the treatment period 30 s-3 h post-test. However, no evidence for amnesia is observed if scopolamine-HCl injections are delayed for 6 h postsession. This important latter observation attests to the absence of any significant proactive effects of scopolamine on the ability of mice to perform the retention test via possible long-term effects on attention, motivation, or locomotor performance. These results thus constitute evidence for the existence of a limited (30 s-3 h) time gradient for vulnerability of the early memory trace to disruption by scopolamine. The present results are discussed in relation to our previous direct neurochemical observations describing the differential time courses of intervention of the ascending septohippocampal and nBM-cortical cholinergic pathways in the postlearning period. In particular, the presently observed time window concerning post-test vulnerability to scopolamine-induced amnesia corresponds more closely to the time course of the acute activation of the nBM-cortical cholinergic pathway, induced by testing with the same spatial memory protocol as used in the present study in mice.

Animals↗

PubMed1993

On resolving the enigma of infantile amnesia.

Historical and current theories of infantile amnesia are examined. To evaluate the viability of these theories, as well as the phenomenon of infantile amnesia itself, a review of memory development from birth through the preschool years is provided, including an overview of relevant perceptual and neurological maturation. In the context of this review, extant theories of infantile amnesia are shown to falter, and it is concluded that infantile amnesia is a chimera of a previously unexplored relationship between the development of a cognitive sense of self and the personalization of event memory. This hypothesis is examined in detail and discussed in the context of related developments in language and social cognition.

Awareness↗

PubMed2000

A study of anxiety, and midazolam-induced amnesia in patients having lower third molar teeth extracted.

We studied 60 patients to find out whether anxiety affects the dose of midazolam necessary for sedation, and whether operating time, dose of midazolam, or technique have any influence on levels of amnesia and anxiety. A pilot study preceded the main study in which 20 patients were given local anaesthesia only and 20 local anaesthesia and intravenous sedation. Patients in the main study group (n = 60) received both local anaesthesia and intravenous sedation. The dose required for sedation was not linked to amnesia, pulse rate, blood pressure, or preoperative anxiety. Sedation did significantly reduce postoperative anxiety scores, (P< 0.001) and amnesia was affected by operating time; complete surgical amnesia seemed to last about 25 minutes.

Adult↗

PubMed2004

Posthypnotic amnesia for autobiographical episodes: influencing memory accessibility and quality.

The authors examined the impact of posthypnotic amnesia on the accessibility and quality of personal memories. High, medium,and low hypnotizable individuals recalled two autobiographical episodes and rated those memories. During hypnosis, subjects were given a posthypnotic amnesia suggestion that targeted one of the episodes. After hypnosis, they recalled and rated their memories of the episodes. The posthypnotic amnesia suggestion influenced the accessibility and quality of autobiographical memory for high and some medium, but not low, hypnotizable participants. The article discusses these findings in terms of investigating and understanding the impact of posthypnotic amnesia on autobiographical memory.

Adolescent↗

PubMed1996

A study of recovery of memory function in a case of witnessed functional retrograde amnesia.

We describe a case of transient functional retrograde amnesia that had features of a fugue state, and that was accompanied by loss of personal identity and significant autobiographical amnesia. Uniquely, we were able to gather information from witnesses who observed the episode from its onset, and we were also able to monitor the acute stages of recovery of memory function over the subsequent four-week period. The profile of memory loss was characterised by impaired performance on both autobiographical and public events memory tasks, in the context of normal anterograde memory test scores. Shrinkage of retrograde amnesia took place over a four-week period, with autobiographical and public events components of retrograde memory recovering at the same rate. We discuss the possible role of unconscious processes underlying the episode, as compared to conscious simulation. We argue that most cases of functional retrograde amnesia may represent a combination of conscious simulation and unconscious processes.

Journal Article↗

PubMed1994

MRI volumetry of medial temporal lobe structures in amnesia following herpes simplex encephalitis.

Using a magnetic resonance imaging-based volumetry, we quantified the volumes of the hippocampal formation (HF), parahippocampal gyrus (PHG), amygdaloid body (AMB), and anterior temporal neocortex (ATN) in 5 post-herpes simplex encephalitic (post-HSE) patients with temporal lobe damage and memory impairment at 12-52 months after the onset, and in 10 age-matched control subjects. In the post-HSE patients, the HF (p < 0.001) and PHG (p < 0.005) were significantly atrophic, while the AMB (p = 0.155) and ATN (p = 0.102) were smaller but not significantly. Performances on the verbal learning memory tests correlated highly with the HF volume, and length of dense retrograde amnesia with the PHG atrophy. Two patients with severe lasting amnesia had a marked atrophy of the HF and PHG, while 3 patients with good recovery from initial amnesia had temporal lobe structures larger than 50% of the control mean volumes. These results suggest that anterograde and retrograde memory functions involve different neural structures; the former is related to the HF and the latter to the PHG. For producing lasting amnesia, either severe HF damage or a combined damage of the HF and PHG might be necessary.

Acyclovir↗