Cerebral mapping in patients with dementia of Alzheimer's type

INTRODUCTION: The electric cerebral activity maps complement the conventional electroencefalography quantifying electric cerebral activity. One of the applications is in Alzheimer's dementia. OBJECT: The object of this study is to analyse the differences in the electric cerebral activity, by means a quantified EEG, in DAT and SDAT when compared with a control group of the same age. MATERIAL AND METHODS: Thirty patients meeting the criteria of probabledementia (NINCDS-ADRDA) in the senile (n = 19) and presenile (n = 11) form were studied. They were compared with a control group of the same age, 20 individuals older than and 17 younger than 65. RESULTS: The patients suffering from senile dementia as well as those suffering from the presenile form showed a significative increase of the delta and theta bands. On the other hand, a significant reduction of the alfa frequency bands and mainly those of beta was observed in the patients with ADT but not in the ADST ones. The significant increase of the slow bands in ADT and ADST and the significant decrease of the fast bands in ADT have been found in wide areas. Topographically the biggest affect has been registered in the frontal regions for the beta bands in ADT. CONCLUSIONS: The differences found in the electrical activity, depending on the age, would support Alzheimer's disease heterogeneity.     

Preliminary findings of high-dose thiamine in dementia of Alzheimer's type

Thiamine is important not only in the metabolism of acetylcholine but also in its release from the presynaptic neuron. Pathologic, clinical, and biochemical data suggest that thiamine deficiency is detrimental to the cholinergic system and that thiamine-dependent enzymes may be altered in Alzheimer's disease. Two previous studies reported contradictory results in patients with dementia of Alzheimer's type treated with 3 g/day of thiamine. In the present study, we examined the effects of 3 to 8 g/day thiamine administered orally. Our results suggest that thiamine at these pharmacologic dosages may have a mild beneficial effect in dementia of Alzheimer's type. The mechanism of the observed effect is unknown, but the findings warrant further investigation, not only for their therapeutic implications but for their possible etiologic clues. In addition, the results suggest long-term carry-over effects that should be considered in the design of future studies.     

WAIS-R intersubtest scatter in patients with dementia of Alzheimer's type

This study explored the relationship between three indices of intersubtest scatter and level of cognitive deterioration in a sample of 104 patients with dementia of Alzheimer's type, who ranged in age between 52 and 84 years. Scatter was highly related to education and premorbid level of functioning. Advancement of dementia was shown to be associated with decrease in scatter, which suggests caution in interpretation of high magnitude of inter-subtest scatter as an indication of brain dysfunction. Easy-to-calculate range of scatter proved to be adequate measure of scatter. Calculation of more complex indices, such as PVI, provides only minimal incremental gain.     

Role of Alzheimer's type dementia among dementias of the elderly]

In the authors experience of a memory clinic, about 2/3 of the patients fulfilled the criteria for dementia and among the demented patients 2/3 had probable Alzheimer's disease. Vascular dementia is the second cause of dementia in elderly people, but two other degenerative disorders fulfilling the NINCDS-ADRDA criteria for Alzheimer disease (Mc Khann et al., 1984) account for degenerative dementia. There is now a consensus for the clinical diagnosis and the neuropathological aspects of these two diseases: Dementia with Lewy Bodies (Mc Keith et al., 1996) and fronto-temporal dementia (the Lund and Manchester groups, 1994). The authors emphasize the clinical aspects of those two diseases at an early stage in comparison with dementia of Alzheimer type.     

Semantic homophone priming in patients with dementia of the Alzheimer's type.

To examine the role of semantic processes in the verbal priming deficits of patients with dementia of the Alzheimer type (DAT), 15 DAT patients, 8 amnesic patients, and 12 controls were administered a homophone spelling bias task. Ss' spellings were biased against their previously preferred homophone spellings by presenting the homophones aurally in a semantically related context. The results showed that DAT patients were not significantly different from controls or amnesic patients on the immediate priming measure. However, both patient groups' semantic priming effects decayed more rapidly and their recognition performance was significantly impaired in relation to those for control Ss. These results suggest that DAT patients can perform normally on some semantic priming tasks if the task demands are within the capacity of the patients' remaining intact semantic structure and if the delay between presentations is brief. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task demands and sentence comprehension in patients with dementia of the Alzheimer's type

Patients with dementia of the Alzheimer's type (DAT) and matched normal controls were given three tests of syntactic comprehension in which nonlinguistic visual and memory task demands were varied. In all tasks, subjects were presented spoken semantically reversible sentences with a variety of syntactic structures and required to match the sentence to a picture. In the first experiment, subjects matched the spoken sentence to one of two pictures that appeared either before or immediately following the presentation of the sentence. The target picture depicted the spoken sentence correctly and the foil depicted the reversed thematic roles to those in the sentence (i.e., it was a syntactic foil). The second experiment employed a sentence video-verification task in which subjects were required to determine if the spoken sentence matched a videotaped depiction of the action in the sentence or a syntactic foil. In the third experiment, in different conditions, subjects were required to determine whether the spoken sentence matched a single picture or to choose the picture that matched the sentence from an array of two or three pictures. In this experiment, both lexical and syntactic foils were used. In all tasks, DAT patients were affected by the number of propositions in the presented sentence, but not by the syntactic complexity of the sentence. Control subjects also were unaffected by the syntactic complexity of the sentence; the number-of-proposition effect was present in some experiments in the control population. Comparison of performance across the one-, two-, and three-picture versions of the task showed that the magnitude of the effect of number of propositions increased as the number of pictures in the array increased. In addition, analysis of the data from each of the tasks separately showed that the effect of number of propositions only occurred when subjects were attempting to match the target to a syntactic foil (one-picture version) or to choose between the target and a syntactic foil (two- and three-picture versions). The results support the view that patients with DAT do not have disturbances affecting syntactic processing. In addition, they suggest that the effect of number of propositions arises at a stage of analysis that is partially separate from assigning sentence meaning, such as in holding a representation of the sentence in memory until the pictures can be analyzed and encoded and/or in comparing the results of the picture analysis with a stored representation of the sentence meaning.     

Behavioural disturbances in psychiatric inpatients with dementia of the Alzheimer's type in Taiwan

This report studied behavioural disturbances in psychiatric inpatients with dementia of the Alzheimer's type (DAT) in Taiwan. The sample consisted of 75 inpatients with DAT who were consecutively admitted to the geropsychiatric ward. Their behavioural disturbances were obtained from semistructured interviews with families and ward observation. There were eight main behavioural disturbances: getting lost, repetitive phenomena, sleep disturbance, aggression, wandering, hyperphagia, hoarding behaviour, and inappropriate sexual behaviour. Number of behavioural disturbances, wandering, hyperphagia and sleep disturbance were significantly associated with the severity of cognitive impairment.     

Parkinson's dementia and Alzheimer's dementia: an evoked potential comparison

Auditory endogenous event-related potentials (ERPs) and flash visual evoked potentials (VEPs) were recorded in 26 elderly patients with idiopathic Parkinson's disease (PD), 14 with dementia and 12 non-demented, 16 elderly patients with Alzheimer dementia (AD) and 15 cognitively intact controls. ERP P3 and flash-VEP N2, P2 and delta (P2-P1) latency measures were significantly increased in the demented PD group compared with controls. The ERP P3 latency was also significantly delayed in the AD group compared with controls, but the differences in the flash-VEP measures from controls were not significant. No significant differences were noted between the PD groups, except for a significantly shorter flash-VEP N1 latency in the demented PD group; this was also the only significant evoked potential difference between the AD and PD dementia groups, which were otherwise electrophysiologically similar.     

Assessment of semantic processing in patients with Alzheimer's type dementia: The release-of-proactive-inhibition paradigm.

Investigated memory functioning in 10 patients with dementia of Alzheimer's type (DAT [aged 54–87 yrs]) and 20 age-matched normal controls (CTLs) by using the release-from-proactive-interference paradigm. DAT Ss exhibited lower correct recall and higher intrusion rates than did CTLs. DAT Ss did not show the expected build-up and release from proactive interference when correct recall was considered but showed the expected pattern when intrusion rate was considered. CTLs showed evidence of semantic processing on both measures. Results are discussed in relation to the defects in semantic memory hypothesized in Alzheimer's disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Risk factors for type 1 reactions in leprosy

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm that previously has been described only in children. We report three cases occurring in adults. The patients, two men and one woman, were aged 64, 55, and 48 years, respectively. Lesions arose on the chest wall, the lateral aspect of the neck, and in the groin and buttock, and each was situated in superficial soft tissue. Tumor size ranged from 0.9 to 7 cm. Histologically, in all cases a lobular or nodular growth pattern of densely packed spindle-shaped tumor cells closely associated with small slitlike and sievelike blood vessels was seen. Within one lesion, small nodules of plumper, epithelioid tumor cells were identified. Well-formed capillaries frequently containing fibrin thrombi were observed mainly in the periphery of tumor nodules. Areas of hemorrhage and hemosiderin deposits were observed in two cases. Associated lymphangiomatosis composed of diffusely infiltrating lymphatic spaces of the dermis and subcutis was present in one case. Nuclear atypia was minimal in all cases, and mitotic figures were rare in two cases; in one case up to 6 mitoses in 10 high-power fields were noted focally. Immunohistochemically, well-formed capillaries stained positively for all the vascular markers used; however, endothelial cells lining the small slitlike and sievelike vascular spaces did not stain for von Willebrand factor. At least focally, actin-positive pericytes were seen. Neoplastic spindled cells stained only focally for CD34 and CD31. Two lesions were excised with clear margins; in one case only repeated biopsies were done. Follow-up information between 14 and 28 months revealed no sign of recurrence or metastasis. In adults, the differential diagnosis of KHE comprises especially Kaposi's sarcoma and spindle cell hemangioendothelioma; further differential diagnoses include tufted hemangioma and cellular capillary hemangioma, which occur rarely in adults.     

Event-related brain potentials during semantic categorization in normal aging and senile dementia of the Alzheimer's type

To assess the effects of normal aging and senile dementia of the Alzheimer's type (SDAT) on semantic analysis of words, we examined the N400 component of the event-related potential (ERP) elicited during the processing of highly constrained (opposites) and less constrained materials (category-category exemplars) in 12 young control subjects, 12 elderly control subjects and 12 patients with SDAT. We employed a priming paradigm in which a context phrase was spoken and a target word (congruent or incongruent) was presented visually. The N400 effect was reduced in amplitude and delayed in the elderly control group relative to that of the younger subjects, and was further attenuated in amplitude, delayed in latency and somewhat flatter in its distribution across the scalp in the SDAT patients. These findings are consistent with less efficient processing and integration of lexical items with semantic context in normal aging, which is further exacerbated by SDAT. Differences in the N400 range associated with the opposite and category conditions were observed only in the young subjects, suggesting less use of controlled attentional resources or perhaps weaker associative links with age.     

The spectrum of category effects in object and action knowledge in dementia of the Alzheimer's type.

The validity and origin of category effects in the anomia demonstrated by individuals with dementia of the Alzheimer's type (DAT) remains controversial. Twenty DAT subjects were tested with picture naming and semantic association judgement tests. Picture and word stimuli were drawn from biological, nonbiological, and actions–verbs categories, all of equal difficulty and previously normed on elderly controls. DAT subjects made significantly more naming and semantic judgement errors in the biological category than in the nonbiological category. They were relatively more accurate in naming and making judgements for actions–verbs when presented as words or as 5-s animations. When line drawings of actions were shown for naming, performance deteriorated significantly. Converging results from these 2 tasks provide strong evidence for a semantic memory impairment preferentially affecting biological items to a greater extent than nonbiological items or action verbs in DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stroop performance in healthy younger and older adults and in individuals with dementia of the Alzheimer's type

Components of the Stroop task were examined to investigate the role that inhibitory processes play in cognitive changes in healthy older adults and in individuals with dementia of the Alzheimer's type (DAT). Inhibitory breakdowns should result in an increase in Stroop interference. The results indicate that older adults show a disproportionate increase in interference compared with younger adults. DAT individuals show interference proportionate to older adults but a disproportionate increase in facilitation for congruent color-word trials, and an increased intrusion of word naming on incongruent color naming trials. An ex-Gaussian analysis of response time distributions indicated that the increased interference observed in older adults was due to an increase in the tail of the distribution. Application of the process dissociation analysis of the Stroop task (D.S. Lindsay & L.L. Jacoby, 1994) indicated that older adults showed increased word process estimates, whereas DAT individuals showed differences in both color and word process estimates. Taken together, the results are consistent with an inhibitory breakdown in normal aging and an accelerated breakdown in inhibition in DAT individuals.     

Cholinergic modulation, visual function and Alzheimer's dementia

Electrophysiological evidence at a cellular level and in vivo macroelectrode recordings converge in indicating a degree of specificity of acetylcholine action in vision. Acetylcholine (ACh) function is also thought to play a significant role in memory, learning and other cognitive processes. In this respect, ACh action is suggested to serve in both sensory and cognitive processes. The pharmacological blocking of brain muscarinic transmission has been proposed as a model of geriatric memory impairment and Alzheimer's dementia. Visual electrophysiological testing is deemed of diagnostic specificity for this disease. ACh brain neurotransmission, however, mostly contributes to the modulation of nonspecific aspects of cognition, such as arousal or attention. Alzheimer's dementia results from complex neuron alterations [which also affect muscarinic receptors among other (sub)cellular structures] rather than simply reflecting ACh impoverishment. A substantial loss of retinal ganglion cells is documented in patients with Alzheimer's disease and is consistent with electrophysiological observations. However, it is unclear to what extent the dysfunction of the visual system observable in Alzheimer's dementia is qualitatively different from that occurring spontaneously during aging. The dissimilarities between the effect of acute muscarinic blocking (e.g. by scopolamine) and dementia outnumber the similarities. Accordingly, the conventional ACh agonist-antagonist model of dementia now appears questionable, and replacement treatment with compounds enhancing ACh function proved disappointing. It is suggested that (nonspecific) ACh action becomes function-specific, as determined by the architecture of local brain circuits in which it is involved.     

Risk factors for clinically diagnosed Alzheimer's disease: a case-control study of a Greek population

Many efforts have been made to trace the causes of Alzheimer's disease (AD). There are, however, many points of controversy among reports from the same country as well as among reports from different countries. The current study is a case-control study to determine the risk factors in the development of AD in Greece. Sixty-five patients with AD and 69 age-matched controls were examined. All patients with AD fulfilled the DSM-IV criteria for AD and NINCDS-ADRDA criteria for probable AD. Demographic characteristics such as gender, current marital status, who he/she is living with, education, main place of residence in childhood, adulthood, and late life, occupational hazards, patient's medical history (history of diabetes mellitus and hypertension), life habits like alcohol consumption and smoking, and a history of head trauma, heart attack, stroke, parkinsonism, or depression were collected from the subject or from an informant. A family history of selected diseases (hypertension, diabetes mellitus, dementia, Parkinson's disease, Down's syndrome, stroke) was also elicited. Ages of father and mother at birth were also recorded. Chi-square test, Kruskal-Wallis analysis of variance, cluster analysis, and logistic regression analysis were used for statistical analysis. The results (chi-square test) showed a statistically significant difference between patients with dementia of the Alzheimer type and controls as far as marital status (p = .04), the subject's history of major depressive episode (p = .02), and family history of dementia (p = .002) were concerned. Logistic regression analysis results produced a complex model of family aggregation of dementia, with patients with a history of depression and family history of dementia having an up to seven times higher risk of developing AD. These findings, especially a family history of dementia, are consistent with most of the literature.     

Failure to control prepotent pathways in early stage dementia of the Alzheimer's type: Evidence from dichotic listening.

The authors examined the right ear advantage in a dichotic listening task in healthy aging and very mild and mild stages of Alzheimer's disease. Subjects were simultaneously presented 3 pairs of digits to the left and right ears (e.g., left ear: 4, 3, 1; right ear: 9, 2, 5) for immediate ordered recall. Four lists of triads were presented, varying in presentation rate between digit pairs within a triad (0.5, 1.0, 1.5, 2.0 s). Results indicated that the very mild and mild Alzheimer's groups showed a larger right ear advantage in free recall compared with the healthy controls, indicating a tendency to respond to the prepotent left hemisphere pathway for language processing. Also, the right ear advantage and proportion of switches made during recall were correlated with psychometric measures of frontal lobe function in the mild Alzheimer's group but not in the very mild or healthy control groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rats with nucleus basalis magnocellularis lesions mimic mnemonic symptomatology observed in patients with dementia of the Alzheimer's type.

College students, healthy elderly subjects, patients diagnosed with mild or moderate dementia of the Alzheimer's type, as well as rats with small or large lesions of nucleus basalis magnocellularis (NBM) were tested on an order memory task for a 6- or 8-item list of varying spatial locations. Similar patterns of order memory deficits as a function of serial order position were observed in rats with small or large NBM lesions and patients with mild or moderate dementia of the Alzheimer's type. The results provide support for the possibility that rats with NBM lesions might mimic the mnemonic symptomatology of Alzheimer's disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)