Alzheimer Disease: Delazer M

Schmidt R, Kienbacher E, Benke T, Dal-Bianco P, Delazer M, Ladurner G, Jellinger K, Marksteiner J, Ransmayr G, Schmidt H, Stögmann E, Friedrich J, Wehringer C. · Univ.-Klinik für Neurologie, Medizinische Universität Graz. · Neuropsychiatr. · Pubmed #18381051 No free full text.

Abstract: The prevalence of Alzheimer disease is higher in women than in men. In the age group 65-69 years 0.7% of women and 0.6% of men suffer from the disease with increasing frequencies of 14.2% and 8.8% in individuals aged 85-89 years. The incidence is also higher in demented women. In Austria 74.1% of Alzheimer patients older than 60 years are women. Several studies report more pronounced language, mnestic, semantic and orientation deficits in women, but methodological shortcomings might be responsible for this finding. The validity of results reporting a more rapid cognitive decline in women can also be questioned. Women have a broader spectrum of dementiarelated behavioural symptoms with a predominance of depression, while aggression is more frequent in men than in women. Biological explanations for gender-specific differences in the phenotype of Alzheimer s disease include different brain morphology and function with higher susceptibility for pathological lesions in women and greater cognitive reserve in men. Sex differences were also reported for expression of antioxidative enzymes and post-menopausal hormonal changes. Interactions between gender nd response to treatment, if any, are subtle and have large intra-individual variability. In Austria, two thirds of patients receiving attendance allowance are women. Care takes place in 80% by the families and is provided by women in 78%. The rate of female care-givers in partly institutionalized care units in 91% in nursing homes it is 84%.

Sinz H, Zamarian L, Benke T, Wenning GK, Delazer M. · Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria. · Neuropsychologia. · Pubmed #18339408 No free full text.

Abstract: Decisions under ambiguity and decisions under risk are crucial types of decision making in daily living at any age. This is the first study assessing these two types of decisions in patients with mild dementia of Alzheimer's type (DAT) by means of the Iowa Gambling Task (IGT) and a newly developed, Probability-Associated Gambling (PAG) task. While rules for gains and losses are implicit in the IGT, in the PAG task rules are explicit and winning probabilities, which change from trial to trial, can be estimated. Results of the IGT indicated that DAT patients made more disadvantageous decisions than healthy controls. Patients also shifted more frequently among decks, i.e. under ambiguity decisions were taken randomly and no advantageous strategy was established over time by DAT patients. Thus, not only actual choices but also development of advantageous strategies may be revealing about decision making in the IGT. Compared to controls, patients demonstrated less advantageous choices in the PAG task as well. They gambled more often in the low winning probabilities and less frequently in the high probabilities than healthy participants. Patients' performance on both tasks correlated with measures of executive functions. Findings of the present investigation are consistent with the early pathological cerebral changes and related (cognitive, emotional) deficits reported for DAT. As suggested by our study, decisions under ambiguity as well as decisions under risk are impaired in mild DAT. It may thus be expected that patients with mild DAT have difficulties in taking decisions in every-day life situations, both in cases of ambiguity (information on probability is missing or conflicting, and the expected utility of the different options is incalculable) and in cases of risk (outcomes can be predicted by well-defined or estimable probabilities).

Zamarian L, Semenza C, Domahs F, Benke T, Delazer M. · Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria. · J Neurol Sci. · Pubmed #17628603 No free full text.

Abstract: The present study investigated arithmetic processing in patients with mild dementia of Alzheimer's type (DAT) and patients with mild cognitive impairment (MCI) without dementia. Arithmetic processing (e.g., 2+3=?, 3 x 4=?) was evaluated in (1) 'blocked' condition (without extra load on attentional and executive functions), in (2) 'mixed' condition (shifting between different operations was required), and in (3) 'Stroop-like' condition (executive control and inhibition of automatic retrieval processes were needed). Both DAT and MCI patients showed intact arithmetic knowledge retrieval from long-term memory in the blocked condition. However, DAT patients were compromised whenever load was put on executive functions, whereas MCI patients succeeded to shift between operations (mixed condition) but had difficulties to inhibit overlearned associations (Stroop-like condition). In line with previous studies, these findings point to the contribution of attentional and executive functions in arithmetic. The present investigation is also of clinical relevance: it suggests that it may be important to assess arithmetic processing not only in blocked presentation but also in mixed presentation. The mixed condition has a high ecological value because it mimics daily-life arithmetic activities (e.g., checking the grocery bill). As indicated by the present results, DAT and MCI patients who are in the normal range at routine neuropsychological (blocked) arithmetic assessments may experience difficulties by extra requirement of non-numerical resources. That means, they possibly process arithmetic not efficiently in daily-life situations.

Delazer M, Sinz H, Zamarian L, Benke T. · Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria. · Neuropsychologia. · Pubmed #17328931 No free full text.

Abstract: Decision-making in mild dementia of Alzheimer's type (DAT) was assessed in a gambling task with stable and explicit rules [Game of Dice Task; Brand, M., Labudda, K., Kalbe, E., Hilker, R., Emmans, D., Fuchs, G., et al. (2004). Decision-making impairments in patients with Parkinson's disease. Behavioural Neurology, 15, 77-85]. DAT patients in an early stage of the disease chose safe alternatives as frequently as healthy elderly persons and did not show risky behaviour as has been reported for other neurological patient groups. However, a more detailed analysis disclosed important differences between DAT and healthy elderly. Compared to healthy controls, DAT patients shifted more frequently between safe and risky alternatives and showed less consistent response patterns. Frequent changes between strategies indicate that decisions were taken randomly, that no advantageous strategy was established and that no consistent response pattern was developed over time. As regards performance changes over the task, healthy participants had a stronger tendency towards safe and advantageous responses than DAT patients. While healthy controls showed learning as the task proceeded, DAT patients did not adapt their strategies. The proportion of "consistently safe responders" was significantly higher in the control group than in the DAT group. Analysis of reaction times indicated that differences in response behaviour were not due to fast and impulsive decision taking in the DAT group. DAT patients' response pattern may be attributed to deficits in learning and in executive functions. The frequency of changes between safe and risky choices proved to be a fair predictor for the distinction between mild DAT and healthy aging.

Delazer M, Karner E, Proell S, Benke T. · Clinical Department of Neurology, Innsbruck Medical University, Innsbruck. · J Clin Exp Neuropsychol. · Pubmed #16723320 No free full text.

Abstract: Patients affected by Alzheimer's disease (DAT) showed considerable difficulties assessing the numerosity of complex dot patterns (up to 30 dots). Patients' and controls' performance was found to be modulated by the spatial array of dot patters. Dots presented in curved lines were easier to count than dots in circle arrays or in random arrays. Highly significant between group differences were found in counting dots in circle arrays, but not in counting curved lines. Patients and controls differed in the choice of counting strategies. While controls efficiently adapted their counting strategies to the respective dot patterns, DAT patients were not able to adapt counting strategies to the requirements of the spatial arrays. Analysis of error types further evidenced the particular difficulties of patients. Several recounts in counting circle arrays reflected difficulties to stop counting, while omissions in random patterns suggested deficits in monitoring already counted items. Results of this study suggest that deficits in executive functions prevented patients from selecting and adapting counting strategies in order to keep track of already counted items, to enhance accuracy and to reduce demands on cognitive resources.

Martini L, Domahs F, Benke T, Delazer M. · Universitätsklinik für Neurologie, Innsbruck, Austria. · J Int Neuropsychol Soc. · Pubmed #14632246 No free full text.

Abstract: The present study investigated everyday numerical abilities in a group of 21 patients affected by mild to moderate dementia of Alzheimer's type (DAT). Though patients did not differ from a control group in standard laboratory tests tapping transcoding, number comparison, simple calculation, and estimation, they showed significant difficulties in numerical tasks embedded in an everyday context, such as handling money, a bus schedule, or a television program. Patients' difficulties were attributed to those multiple cognitive demands which are inherent to real situations as compared to well-structured abstract paper-and-pencil tasks. Overall, the study suggests that the examination of numerical abilities in DAT patients should go beyond abstract paper-and-pencil tasks which can only partially reflect the actual numerical skills in DAT and should therefore include also tasks simulating everyday life situations. Assessment of everyday numerical skills may be crucial in planning adequate support for patients, for example in handling money, but also in designing targeted training programs.

Delazer M, Semenza C, Reiner M, Hofer R, Benke T. · Klinik fur Neurologie, Universitätsklinik für Neurologie, Anichstrasse 35, 6020 Innsbruck, Austria. · Neuropsychologia. · Pubmed #12887984 No free full text.

Abstract: Proper name anomia is a frequent finding among patients in the early stages of Alzheimer's disease. The present study investigates naming of famous persons in a group of DAT patients, a group of persons with mild cognitive impairment (MCI) and healthy controls. The study is aimed at distinguishing the relative contributions of semantic and post-semantic factors to difficulties in proper name retrieval. As shown by a significantly lower score in answering semantic questions, DAT patients retrieve less biographical knowledge related to famous persons than healthy elderly subjects and persons with mild cognitive impairment. This finding is in line with the frequent observation of semantic deficits in early and moderate DAT. The high number of Tip-of-the-Tongue (TOT) answers in DAT found in relation to few spontaneously named items shows that post-semantic deficits are as important as semantic deficits in determining anomia for people names in DAT. Moreover, DAT patients were less sensitive to phonological cueing than healthy persons or persons with mild cognitive impairment. These findings suggest that proper name anomia in DAT is not only due to semantic deficits, but also to problems in accessing the phonological representation, as well as to a degradation of phonological representations. Thus, naming deficits in DAT differ not only quantitatively, but also qualitatively from the difficulties of healthy elderly persons. No significant differences were found between persons with mild cognitive impairment and healthy controls in proper name retrieval.

Kaufmann L, Montanes P, Jacquier M, Matallana D, Eibl G, Delazer M. · University Clinic Innsbruck, Austria. · Brain Cogn. · Pubmed #12030476 No free full text.

Abstract: We studied the relationship between basic numerical knowledge and arithmetics (facts and procedures) in early Alzheimer's Disease (AD). In most patients, basic numerical knowledge was found to be preserved, as reflected by low error rates, distance effect in number comparison, and subitizing in naming numerosities. However, within arithmetics, AD patients exhibited decreased fact and procedural knowledge. Interestingly, double dissociations were found not only between facts and procedures but also between basic numerical knowledge and arithmetics. Thus, our results suggest that basic numerical knowledge need not be a prerequisite for the maintenance of arithmetics, but rather corroborate calculation models that postulate the functional independence of its components. Further, we found patient specific error types which might serve to identify early AD. The follow-up about one year later indicated significant qualitative, but only marginal quantitative performance changes.

Mantovan MC, Delazer M, Ermani M, Denes G. · Department of Neurology, University of Padua, Italy. · Cortex. · Pubmed #10213532 No free full text.

Abstract: The study investigates calculation abilities in 12 patients with probable Alzheimer's disease (AD) and compares them to calculation abilities of healthy control subjects (NC) and patients with focal left hemisphere lesions (LHL). AD patients scored significantly lower than NC in all calculation tasks and lower than LHL patients in the execution of complex written calculation, but not in the retrieval of arithmetic facts. In the AD group a subject-by-subject error analysis on the complex written calculation showed a low consistency and a high variability of error types. It is suggested that AD patients' difficulties in complex calculation arise from a monitoring deficit and not from incomplete or distorted calculation algorithms. Overall, deficits in monitoring calculation procedures may be an early and common symptom of AD.