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PubMed1977

Encoding in senile dementia and elderly depressives: a preliminary study..

Forty-seven subjects (19 elderly dements, 18 elderly depressives, 10 elderly physically ill) were given a continuous false recognition technique (FRT) in a test battery including a measure of short-term memory and the Kendrick Synonym Learning Test. Results were analysed according to signal detection theory and interpreted in terms of an encoding breakdown. Depressives were found to be characterized by conservative error-free performance whereas the demented made more errors, partly because of their more liberal criterion and partly because of their greater loss of encoding characteristics. From these results, an optimal cut-off score was chosen for differential diagnosis using the FRT. This was shown to hold more promise than the SLT in discriminating between dementia and depression.

Aged↗
PubMed1991

Memory loss following radiotherapy for nasal pharyngeal carcinoma--an unusual presentation of amnesia.

In this article we describe a patient who developed amnesia several years after receiving a second course of radiotherapy treatment for nasopharyngeal cancer (NPC). Detailed assessment of memory indicated a marked anterograde impairment for verbal material with less impaired non-verbal memory. A dense retrograde deficit was also present, reflected in both poor event memory and loss of general knowledge. Performance on other tests indicated a mild intellectual deficit but no other cognitive impairments. The findings indicate a striking memory disorder arising from late temporal lobe necrosis. These findings stress the importance of assessing neuropsychological sequelae when evaluating the long-term outcome of radiotherapy for NPC and other cancers of the head and neck.

Adult↗
PubMed1977

Trying to bridge some neuropsychological gaps between monkey and man.

It is puzzling that some anatomical systems in the brains of monkeys and men appear to function quite differently although there is no established basis for this either in their fine-grained anatomical organizations or in the inherent behavioural capacities of the two species. It is suggested that in some instances the discrepancies may arise because inappropriate tests have been used with the animals, and examples are given of positive evidence for cross-modal perception and a possible experimental basis for hemispheric specialization in the monkey. In other instances, they may derive from inadequate or inappropriate methods of testing human subjects, and attention is focused on two major examples: memory disorders associated with medial temporal lobe lesions and blindness associated with occipital lesions in man. In both examples it has been generally concluded that the human deficits are far more severe and even qualitatively different from those studied in the monkey. Evidence suggests that the discrepancies may be resolved if human subjects are tested not by means of 'commentary' questions (e.g 'do you see this? or 'do you recognize this?') but by methods that depend upon forced-choice or identification procedures that are more closely related to those used with animal subjects. It is argued that the study of dissociations between a capacity and its acknowledgement by a human subject may suggest a type of brain organization that is consistent both with the engineering approach that Craik would have fostered and also with one that places older and newer brain structures in the single evolutionary framework.

Animals↗
PubMed1979

Physostigmine and recent memory: effects in young and aged nonhuman primates.

The effect of physostigmine on recent memory was evaluated in young and aged rhesus monkeys. All aged monkeys had previously shown impaired memory. The performance of the young monkeys treated with physostigmine was similar to that recently reported for young humans--no effects at low doses, some improvement at a restricted range of doses, and deficits at the highest dose. Although the aged subjects also improved at the same general doses, their overall response as a group was much more variable than that of the younger subjects. The performance of some aged monkeys was impaired by low doses that did not affect young monkeys. Continued improvement was observed in some aged monkeys at the highest dose, which typically impaired young monkeys. These variable effects across aged subjects suggest that physostigmine cannot easily or reliably be used as an agent for treating geriatric cognition. Nevertheless, the differential age-related effects suggest that appropriate manipulation of the cholinergic system may eventually be developed to alleviate some of the cognitive impairments suffered by aged subjects.

Acetylcholine↗
PubMed1984

Alzheimer's disease: cell-specific pathology isolates the hippocampal formation.

Examination of temporal lobe structures from Alzheimer patients reveals a specific cellular pattern of pathology of the subiculum of the hippocampal formation and layers II and IV of the entorhinal cortex. The affected cells are precisely those that interconnect the hippocampal formation with the association cortices, basal forebrain, thalamus, and hypothalamus, structures crucial to memory. This focal pattern of pathology isolates the hippocampal formation from much of its input and output and probably contributes to the memory disorder in Alzheimer patients.

Aged↗
PubMed1992

Memory after treatment for acute lymphoblastic leukaemia.

Long term survivors of acute lymphoblastic leukaemia (ALL) often experience cognitive difficulties, which may be related to impairment of memory function. Memory ability has been studied in a group of survivors of ALL along with sibling controls and in children who have received treatment for other forms of cancer. Children in the ALL group were found to have significant deficits in memory function in tasks which required the application of strategic planning behaviour. These deficits are potentially remediable by educational strategies.

Adolescent↗
PubMed1981

Old men forget.

Explore the source record for details and available documents.

Aged↗
PubMed2004

Right prosubiculum amyloid plaque density correlates with anosognosia in Alzheimer's disease.

BACKGROUND: Anosognosia is a common manifestation of Alzheimer's disease. There is an association between impaired awareness and frontal-executive cognitive deficits. Anosognosia is also correlated with decreased metabolism in the right hemisphere, particularly in frontal lobe regions. OBJECTIVE: To investigate pathological correlates of anosognosia in Alzheimer's disease. DESIGN: 41 subjects followed longitudinally in the University of Pittsburgh memory disorders clinic and with necropsy verified Alzheimer's disease were divided into two groups, based on previous clinical assessment: +Aware (n = 23) and -Aware (n = 18). A subset analysis matching subjects for dementia severity using mini-mental state examination scores was also carried out (13 +Aware; 13 -Aware). Histopathological data from necropsy brain tissue consisted of senile plaque (SP) and neurofibrillary tangle (NFT) counts (regional density) from four different brain regions in the right and left hemispheres: superior and middle frontal gyri (SMF), superior temporal isocortex (ST), the prosubiculum of the hippocampus (PRO), and the entorhinal cortex (EC). RESULTS: SP density was greater in the right PRO region of -Aware subjects (F = 6.54, p = 0.015) than +Aware subjects. Significant differences between SP or NFT density were not observed in any other regions. In the subset analysis matching for dementia severity, SP density was again greater in the right PRO region of -Aware subjects than in the other regions (F = 12.72, p = 0.002). CONCLUSIONS: Increased SP density in the right PRO region suggests that selective pathological involvement of this area contributes to awareness deficits in Alzheimer's disease. The putative role of the PRO in self appraisal may reflect its interconnections with other medial temporal and prefrontal regions.

Aged↗
PubMed1972

Impairment of memory functions after acute head injury.

When memory functions are evaluated after head injury, two trends are apparent. Acute head injury patients with approximately normal intelligence demonstrate a reduced capacity to utilize structure in delayed recall relative to a control group. Furthermore, head injury patients with low intelligence demonstrate a wider memory deficit than the previous group, affecting perception and immediate recall as well. No relationship was found between severity of injury, recovery, and performance on the memory scale.

Amnesia↗
PubMed1973

Limbic dementia.

This is the second reported case, known to the authors, of complete, but selective, limbic lobe destruction in previously normally functioning central nervous systems. Both cases had an amnestic syndrome, whose characteristics were essentially similar to amnestic syndromes previously documented with less complete limbic destruction, with one difference-confabulation remained a prominent feature in the chronic stages of the memory disorder. Our patient exhibited a behavioural syndrome similar to that reported by Klüver and Bucy in monkeys with bilateral anterior temporal lobectomies. Klüver-Bucy like syndromes in man have usually been reported with surgical lesions, usually in patients with pre-existent brain disorder. Our case illustrates that the syndrome can be produced by necrotizing encephalitic lesions. We suggest that the combination of the above two syndromes is essentially a `limbic dementia'.

Adult↗
PubMed1975

Observations on cortical blindness and on vascular lesions that cause loss of recent memory.

Two long-surviving cases of cortical blindness are described, one total and the other total except for detection of sudden transitions from light to darkness and darkness to light. Both suffered from severe defect of recent memory, which lasted a month in one, and till death after nearly six years in the other. One patient survives. Necropsy findings on the other are given.

Aged↗
PubMed1976

Diencephalic amnesia: a reappraisal.

The anatomical basis of memory disorder related to lesions of the diencephalon is a controversial matter. A study of a patient who developed severe amnesia in association with bilateral metastatic tumour invasion of the medial and posterior thalamus is reported. The findings in this case have led to further discussion of this unsettled issue.

Amnesia↗
PubMed1979

Functional consequences of the transcallosal removal of intraventricular tumours.

Colloid cysts and other benign tumours of the third and lateral ventricles may be exposed through a small incision in the body of the corpus callosum. This approach is practicable even when ventricular dilatation is slight, and is theoretically less likely to cause epilepsy than the more usual transcortical approach. Disturbances of memory have been noted soon after such operations, but do not cause serious long-term disability. Three patients who underwent transcallosal removal of cysts or tumours some years earlier have been tested by procedures designed to demonstrate interhemispheric transfer of information: they were all found to have defects in transfer of tactile data, but not of information obtained visually. They were not aware of this inability, and do not appear to be inconvenienced by it. The transcallosal route is convenient. The operation sacrifices a functionally significant part of the corpus callosum, but the neurological sequelae have seemed acceptable. However, especially in the elderly, stereoventriculoscopic aspiration may be considered as the initial method of treatment.

Adolescent↗
PubMed1994

A central executive deficit in patients with Parkinson's disease.

Eight patients with Parkinson's disease and eight matched controls were tested for concurrent task performance to examine whether Parkinson's disease produces deficits in the coordinating and integrating function of the central executive component of Baddeley's working memory model. Consistent with this prediction, the patients showed a significant decline in performance on a random pursuit tracking task while recalling digit span forward sequences, whereas the controls showed no such change. Performance on the component pursuit and digit span tasks, which did not differ between groups, was equated across subjects by varying the size of a target square and by using individual subjects' digit spans. The patient group also produced poorer word fluency scores and reported higher levels of depression, but there was no significant impairment on the Wisconsin card sort test. There was no association between dual task performance and any psychometric measure, target size, or disease related variables. Baddeley's working memory model is advantageous in providing a rich conceptual basis to explore and characterise cognitive abilities in patients with Parkinson's disease.

Aged↗
PubMed1996

Memory without context: amnesia with confabulations after infarction of the right capsular genu.

OBJECTIVE: To explore the mechanism of an amnesia marked by confabulations and lack of insight in a patient with an infarct of the right inferior capsular genu. The confabulations could mostly be traced back to earlier events, indicating that the memory disorder ensued from an inability to store the temporal and spatial context of information acquisition rather than a failure to store new information. METHODS: To test the patient's ability to store the context of information acquisition, two experiments were composed in which she was asked to decide when or where she had learned the words from two word lists presented at different points in time or in different rooms. To test her ability to store new information, two continuous recognition tests with novel non-words and nonsense designs were used. Recognition of these stimuli was assumed to be independent of the context of acquisition because the patient could not have an a priori sense of familiarity with them. RESULTS: The patient performed at chance in the experiments probing knowledge of the context of information acquisition, although she recognised the presented words almost as well as the controls. By contrast, her performance was normal in the recognition tests with non-words and nonsense designs. CONCLUSION: These findings indicate that the patient's amnesia was based on an inability to store the context of information acquisition rather than the information itself. Based on an analysis of her lesion, which disconnected the thalamus from the orbitofrontal cortex and the amygdala, and considering the similarities between her disorder, Wernicke-Korsakoff syndrome, and the amnesia after orbitofrontal lesions, it is proposed that contextual amnesia results from interruption of the loop connecting the amygdala, the dorsomedial nucleus, and the orbitofrontal cortex.

Amnesia↗
PubMed1998

Fallacies in the pathological confirmation of the diagnosis of Alzheimer's disease.

OBJECTIVE: Necropsy confirmed clinical diagnostic accuracy for Alzheimer's disease is claimed to exceed 90%. This figure contains two fallacies; it includes cases in which Alzheimer's disease exists with other diseases affecting cognition and the studies that report these figures excluded cases without necropsy (verification bias). The effect of these errors is estimated. METHODS: Data were taken from the University of Western Ontario Dementia Study, a registry of dementia cases with clinical and psychometric follow up to necropsy based in a university memory disorders clinic with secondary and tertiary referrals. Data were available on 307 patients; 200 (65%) had clinically diagnosed Alzheimer's disease, 12 (4%) vascular dementia, 47 (15%) mixed dementia, and 48 (16%) had other diagnoses. One hundred and ninety two of 307 cases (63%) died and 122 of 192 fatalities (64%) had necropsies. The pathological material was interpreted in two ways, allowing and disallowing coexistent disease in making a diagnosis of Alzheimer's disease. In cases without necropsy, progressive cognitive loss was used as a marker for degenerative dementia. The outcome measures of interest were the positive predictive value of a clinical diagnosis of Alzheimer's disease allowing and disallowing coexistent diseases and with and without correction for cases that were not necropsied. RESULTS: The clinical diagnoses differed significantly between the population who died and those who did not. In cases without necropsy, 22% had no dementia on follow up, concentrated in early cases and men, showing considerable scope for verification bias. The positive predictive value of a diagnosis of Alzheimer's disease was 81% including coexistent diseases, falling to 44% when limited to pure cases. Combined, these factors reduce the positive predictive value to 38% for pure Alzheimer's disease. CONCLUSIONS: Correction for dual pathology and verification bias halves the positive predictive value of the clinical diagnosis of Alzheimer's disease. Data derived from necropsy studies cannot be extrapolated to the whole population. This has important implications including uncertainty about diagnosis and prognosis and a dilution effect in therapeutic trials in Alzheimer's disease.

Alzheimer Disease↗
PubMed1998

Factors affecting the age of onset and rate of progression of Alzheimer's disease.

OBJECTIVES: To assess the role of cerebrovascular disease, sex, education, occupation, year of birth, leukoaraiosis, congophilic angiopathy, family history, and other demographic factors on the reported age of onset and rate of progression of Alzheimer's disease. METHODS: Analysis of data from the University of Western Ontario Dementia Study, a prospective longitudinal study of dementia patients with clinical and 6 monthly psychometric follow up to postmortem based in a university memory disorders clinic with secondary and tertiary referrals. There were 172 patients with dementia. The main outcome measures were the reported age of onset of cognitive decline as described by the family (available in 168) and rate of progression as measured during the linear phase of the extended scale for dementia, which could be calculated in 66. The cases subdivided into 49 cases of definite Alzheimer's disease without infarcts, 25 cases of otherwise definite Alzheimer's disease with infarcts, 79 cases of probable Alzheimer's disease without infarcts, and 19 such cases with infarcts. RESULTS: The age of onset was not influenced by the rate of progression, the presence of cerebral infarcts, or congophilic angiopathy. Educational level, occupational level, sex, family history, year of birth, reported age of onset, severity at entry, an ischaemic score, and the presence of leukoariosis, affected neither age of onset nor the rate of progression. An earlier year of birth had a major effect and higher education had a minor effect on earlier age of onset. The earlier the year of birth, the lower the educational level and the greater the accrual of cerebral infarcts. CONCLUSIONS: Contrary to series without pathological verification, age of onset in this study was not affected by occupation. Education had a modest effect on earlier reported onset, probably reflecting earlier recognition. As birth year has a strong effect on educational level and the occurrence of cerebral infarcts, this must be taken into account when analysing for risk factors for Alzheimer's disease.

Adult↗