Pure topographical disorientation in novel environments without anterograde amnesia: a case study.

Topographical disorientation (TD) in novel environments is considered to be a part of anterograde amnesia. A 56-year-old woman presented with pure TD only in novel environments following limbic encephalitis. She could not remember directions inside the hospital on weekly outpatient visits; however, her verbal and visual anterograde memories were normal. In the test of learning photographs of scenes, faces, and objects, only her scores for landscapes were worse than those in healthy controls. These findings suggested that her TD specific to landscapes and directions in novel environments was caused by category-specific memory impairment related to bilateral hippocampal and parahippocampal dysfunction.

Anterograde amnesia and disorientation are associated with in-patients without traumatic brain injury taking opioids. Retrograde amnesia (RA) is absent. RA assessment should be integral to post-traumatic amnesia testing.

The Glasgow Coma Scale (GCS) only assesses orientation after traumatic brain injury (TBI). 'Post-traumatic amnesia' (PTA) comprises orientation, anterograde amnesia (AA) and retrograde amnesia (RA). However, RA is often disregarded in formalized PTA assessment. Drugs can potentially confound PTA assessment: e.g. midazolam can cause AA. However, potential drug confounders are also often disregarded in formalized PTA testing. One study of medium-stay elective-surgery orthopaedic patients (without TBI) demonstrated AA in 80% taking opiates after general anesthesia. However, RA was not assessed. Opiates/opioids are frequently administered after TBI. We compared AA and RA in short-stay orthopaedic surgery in-patients (without TBI) taking post-operative opioids after opiate/opioid/benzodiazepine-free spinal anesthesia. In a prospective cohort, the Westmead PTA Scale (WPTAS) was used to assess AA (WPTAS<12), whilst RA was assessed using the Galveston Orientation and Amnesia Test RA item. Results were obtained in n=25 (60±14yrs, M:F 17:8). Surgery was uncomplicated: all were discharged by Day-4. All were taking regular oxycodone as a new post-operative prescription. Only one co-administered non-opioid was potentially confounding (temezepam, n=4). Of 25, 14 (56%) demonstrated AA: five (20%) were simultaneously disorientated. Mean WPTAS was 11.08±1.22. RA occurred in 0%. CONCLUSIONS: AA and disorientation, but not RA, were associated with in-patients (without TBI) taking opioids. Caution should therefore be applied in assessing AA/orientation in TBI in-patients taking opioids. By contrast, retrograde memory was robust and more reliable: even in older patients with iatrogenic AA and disorientation. RA assessment should therefore be integral to assessing TBI severity in all formalized PTA and GCS testing.

Transient global amnesia in immediate postoperative period: A diagnostic dilemma.

INTRODUCTION: Transient Global Amnesia (TGA) is short-term inability to form new memories despite otherwise normal neurological function. There is associated anterograde and retrograde amnesia. The memory loss is often accompanied by repetitive questioning and temporal disorientation while higher cognitive functions are preserved. The symptoms usually resolve by 24h. CASE REPORT: We present an interesting case of 31year old female who was planned for robotically assisted right sided pyeloplasty. 30min after emergence from anaesthesia patient was disoriented, with retrograde and anterograde amnesia, but neurological function was intact. Neurologic imaging revealed no abnormality. 36h later patient was able to recall everything. DISCUSSION: The pathogenesis of TGA has more recently been attributed to cerebral venous hypertension resulting from retrograde jugular venous flow. Precipitating events are Valsalva manoeuvre, emotion/stress/pain, Excessive exertion, sexual intercourse and swimming in cold water. CONCLUSION: TGA presents dramatically, it needs to be differentiated from cerebral event. It resolves on its own. But one needs to be aware of existence of such an entity.

Neuropsychiatric Manifestations of Colloid Cysts: a review of the literature.

Colloid cysts account for approximately 2% of primary brain tumours and the majority of cases are identified in the fourth and fifth decade. They are small, gelatinous neoplasms lined by a single layer of mucin-secreting columnar epithelium that are thought to arise from errors in folding of the primitive neuroepithelium. They develop in the rostral aspect of the third ventricle in the foramen of Monro in 99% of cases and despite their benign histology carry a poor prognosis, with a mortality greater than 10% in symptomatic cases. The location of colloid cysts within the ventricular system results in obstruction of the foramen of Monro as the cyst grows, disrupting the circulation of cerebrospinal fluid (CSF) and causing hydrocephalus. This is the mechanism behind the most common presenting symptoms of postural headache, nausea and vomiting - a clinical picture synonymous with hydrocephalus and intracranial pathology. In addition to these classical neurological symptoms, there is a high prevalence of psychiatric symptoms in the patient population, with symptoms ranging from anterograde amnesia to gustatory hallucination. These symptoms can occur with or without the presence of hydrocephalus, and are thought to be secondary to compression of connecting pathways between the mesocortices and subcortical limbic regions. These symptoms have been shown to be comparative in frequency to the classical symptoms, yet are rarely the reason for referral to a neurological or neurosurgical service for investigation.

Limbic encephalitis presenting with seizures, anterograde amnesia, and psychosis in a patient seven weeks status post immature ovarian teratoma removal.

A paraneoplastic syndrome associated with anti-N-methyl-D-asparate (NMDA) receptors can initially present as a neurologic or psychiatric disturbance. Removal of the tumor is usually curative, and the syndrome is associated with the presence, rather than the history, of tumor. We present a case in which a 25-year-old, Hispanic woman presented with seizures, memory loss, and unusual behavioral changes. The woman had a teratoma removed 2 months earlier. Because of the time course, a paraneoplastic syndrome was initially considered unlikely. Brain imaging, electroencephalography (EEG) and neurologic work-up were negative. The patient was treated for a suspected somatoform disorder and psychosis. Based on the clinical picture, the working diagnosis was changed to delirium due to paraneoplastic limbic encephalitis. A course of intravenous immunoglobins (IVIg), and high dose steroids was administered. The patient's symptoms improved, and she was discharged home. After discharge, studies came back positive for antibodies against NR1/NR2 of the NMDA receptor.

EPS Mid-Career Award 2006. Understanding anterograde amnesia: disconnections and hidden lesions.

Three emerging strands of evidence are helping to resolve the causes of the anterograde amnesia associated with damage to the diencephalon. First, new anatomical studies have refined our understanding of the links between diencephalic and temporal brain regions associated with amnesia. These studies direct attention to the limited numbers of routes linking the two regions. Second, neuropsychological studies of patients with colloid cysts confirm the importance of at least one of these routes, the fornix, for episodic memory. By combining these anatomical and neuropsychological data strong evidence emerges for the view that damage to hippocampal-mammillary body-anterior thalamic interactions is sufficient to induce amnesia. A third development is the possibility that the retrosplenial cortex provides an integrating link in this functional system. Furthermore, recent evidence indicates that the retrosplenial cortex may suffer "covert" pathology (i.e., it is functionally lesioned) following damage to the anterior thalamic nuclei or hippocampus. This shared indirect "lesion" effect on the retrosplenial cortex not only broadens our concept of the neural basis of amnesia but may also help to explain the many similarities between temporal lobe and diencephalic amnesia.

Cerebellar lesions: is there a lateralisation effect on memory deficits?

BACKGROUND: Until recently, neurosurgeons eagerly removed cerebellar lesions without consideration of future cognitive impairment that might be caused by the resection. In children, transient cerebellar mutism after resection has lead to a diminished use of midline approaches and vermis transection, as well as reduced retraction of the cerebellar hemispheres. The role of the cerebellum in higher cognitive functions beyond coordination and motor control has recently attracted significant interest in the scientific community, and might change the neurosurgical approach to these lesions. The aim of this study was to investigate the specific effects of cerebellar lesions on memory, and to assess a possible lateralisation effect. METHODS: We studied 16 patients diagnosed with a cerebellar lesion, from January 1997 to April 2005, in the "Centre Hospitalier Universitaire Vaudois (CHUV)", Lausanne, Switzerland. Different neuropsychological tests assessing short term and anterograde memory, verbal and visuo-spatial modalities were performed pre-operatively. RESULTS: Severe memory deficits in at least one modality were identified in a majority (81%) of patients with cerebellar lesions. Only 1 patient (6%) had no memory deficit. In our series lateralisation of the lesion did not lead to a significant difference in verbal or visuo-spatial memory deficits. FINDINGS: These findings are consistent with findings in the literature concerning memory deficits in isolated cerebellar lesions. These can be explained by anatomical pathways. However, the cross-lateralisation theory cannot be demonstrated in our series. The high percentage of patients with a cerebellar lesion who demonstrate memory deficits should lead us to assess memory in all patients with cerebellar lesions.

Immediate peri-operative memory.

BACKGROUND: Information about anterograde and retrograde amnesias in the immediate peri-operative period is scarce. During this period, assessment of memory for real-life events is also rare. We hypothesized that there would be both anterograde and retrograde amnesias and memory for peri-operative events would be better than for verbal memory. METHODS: We studied 40 patients who underwent general anesthesia and surgery and 19 control volunteers who were matched to the patients but did not have surgery. Patients completed the state anxiety part of the Spielberger State-Trait Anxiety Inventory in the pre-operative period. They were presented with three word lists in the holding area, the operating room before induction of anesthesia and the recovery room. Memory for the words was tested the next day by recall and recognition tests. Memory for events that happened on the day of surgery was tested by administering a questionnaire. The control subjects were tested similarly but did not complete the events questionnaire. Retrograde amnesia would be demonstrated by a decline in patients' memory from the holding area to the operating room which exceeded any corresponding changes in controls; anterograde amnesia would be demonstrated by memory impairment of the patients in the recovery room, relative to controls. RESULTS: Recall and recognition of words were significantly impaired in the recovery room with a decline from 12% in the holding area to zero% in the recovery room for recall and from 43% to 7% for recognition. The decline in memory from the holding area to the operating room was not significantly greater in patients than in controls, 80% vs. 56% for recall and 27% vs. 14% for recognition. There were no significant differences for recognition of events which happened in the three rooms. CONCLUSIONS: We were unable to detect retrograde amnesia. Patients' memory for neutral stimuli in the recovery room was severely impaired. The events questionnaire proved to be insensitive.

Severe amnesic syndrome and collecting behavior after surgery for craniopharyngioma.

Significant neuropsychologic sequelae were induced by total removal of craniopharyngioma via a frontobasal interhemispheric approach. A 50-year-old right-handed man developed severe amnesic syndrome and collecting behavior after total removal of a craniopharyngioma. He had very poor results on tests of learning, recall, and recognition for both verbal and nonverbal tasks. Magnetic resonance imaging revealed damage to the bilateral mammillary bodies and fornices, and N-isopropyl-p-[23I]iodoamphetamine single photon emission computed tomography showed decreased cerebral blood flow in the bilateral frontal lobes, predominantly in the right, and regions around the third ventricle. The present case suggests that damage to the brain structures surrounding the third ventricle associated with surgery for craniopharyngioma may result in amnesic syndrome and collecting behavior. Generally, the frontobasal interhemispheric approach is the optimum choice for the removal of craniopharyngioma without significant sequelae related to the surgical method, but the risk of neuropsychologic disturbances must be kept in mind.

Selective anterograde amnesia with thalamus and hippocampal lesions in neuro-Behcet's disease.

Anterograde amnesia and minimal retrograde amnesia with thalamic and hippocampal lesions in neuro-Behcet's disease is rare. A 50-year-old man presented with forgetfulness and severe memory disturbance after suffering multiple oral and genital aphthous ulcers with erythema nodosum. A neurological examination and a neuropsychological assessment revealed prominent anterograde memory impairment without focal neurological deficits. On brain MRI there were high signal intensity lesions involving right anterior thalamus, left posterior basal ganglia, and left hippocampus. This is a quite selective anterogrde memory deficit in a case of neuro-Behcet's disease caused by parenchymal lesions in the thalamus and hippocampus.

Acquired amnesia in childhood: a single case study.

We report the case of C.L., an 8-year-old child who, following the surgical removal of an ependymoma from the left cerebral ventricle at the age of 4 years, developed significant difficulties in retaining day-to-day events and information. A thorough neuropsychological analysis documented in C.L. a severe anterograde amnesic syndrome, characterised by normal short-term memory, but poor performance on episodic long-term memory tests. In particular, C.L. demonstrated virtually no ability to recollect new verbal information several minutes after the presentation. As for semantic memory, C.L. demonstrated general semantic competencies, which, depending on the test, ranged from the level of a 6-year-old girl to a level corresponding to her actual chronological age. Finding a patient who, despite being severely impaired in the ability to recollect new episodic memories, still demonstrates at least partially preserved abilities to acquire new semantic knowledge suggests that neural circuits implicated in the memorisation of autobiographical events and factual information do not overlap completely. This case is examined in the light of growing literature concerned with the dissociation between episodic and semantic memory in childhood amnesia.