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Aging and dementia

Sunday, October 02nd,   2011 [18:00 - 20:00]

PS_3.001 - Using brain stimulation to study noun and verb processing in primary progressive aphasia

Lacey, E. 1 , Gordon, B. 1 & Hillis, A. 2

1 Cognitive Neurology/Neuropsychology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
2 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Studying the breakdown of language due to degenerative processes in relatively circumscribed brain areas has provided information about where different aspects of language might be stored in the brain. The treatment of impaired language processes and assessment of generalization effects can also tell us how the areas supporting these processes might be interconnected. The brain stimulation technique transcranial direct current stimulation (tDCS), which involves the passing of weak electrical currents through the scalp and skull, has been shown to improve performance in degenerative diseases such as Alzheimer’s and Parkinson’s disease, but has not yet been used in primary progressive aphasia (PPA). The current study used tDCS and behavioral methods to treat noun writing in a person with PPA. Results indicate that tDCS applied over posterior temporal lobe improves noun writing and that this effect may generalize to both written and oral production of verbs. Ongoing data collection examines the effects on noun and verb production of applying tDCS to frontal regions. Results for this participant and others will be discussed in terms of therapeutic mechanisms of tDCS for this population as well as the potential benefits of tDCS in studying noun and verb processing.

PS_3.002 - Cerebral correlates of language plasticity in old adults without cognitive impairment

Emilie, C. 1, 2, 3 , Perrone-Bertolotti, M. 1, 3 , Jouvenel, L. 1, 3 , Moreaud, O. 1, 4 , Toescu, E. 5 & Baciu, M. 1, 3

1 Laboratoire de Psychologie et Neurocognition, UMR CNRS 5105 Université Pierre Mendès-France, Grenoble
2 Structure Fédérative de Recherche N°1, RMN Biomédicale et Neurosciences, Unité IRM 3T, CHU Grenoble, France
3 Structure Fédérative de Recherche « Santé et Société», Université Pierre Mendès-France, Grenoble, France
4 Service de Neurologie, CHU Grenoble, France
5 Clinical and Experimental Medicine, School: Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT

The evolution of our knowledge of normal aging and its evolution now allow the development of strategies to prevent cognitive decline, knowing that dementia increases with age. In this study, we aim at highlighting cerebral correlates of language plasticity in old adults without cognitive impairment by using 2 neuroimaging methods: (i) resting state fMRI (RS-fMRI) in which the magnitude of deactivated regions underlines task-negative network (TNN) and (ii) fMRI of language task activations in which the magnitude of activated regions underlines task-positive network (TPN). 7 young adult volunteers and 7 old adults without cognitive impairment performed categorization tasks (Living) on words and images, respectively. These tasks were used to explore TPN. Moreover, they performed RS-fMRI (participants were instructed to fixate a cross in the middle of the screen during 7 min) in order to explore TNN. Our major result is that older people without cognitive impairment show (when compared to young adults) altered deactivations (decrease) of several TNN regions and higher levels of activation (reduced hemispheric asymmetry) within TPN regions, and particularly in bilateral prefrontal and temporal regions, during language tasks. Reduced asymmetry is congruent with the HAROLD model and compensation mechanism could explain altered links between TPN and TNN.

PS_3.003 - Aging and lexical inhibition: the effect of aerobic exercise on visual word recognition

Dioux, V. 1 , Mathey, S. 2 , Lacassagne, M. 1 , Cometti, D. 1 , Robert, C. 2 & Zagar, D. 1

1 Laboratoire Socio-Psychologie et Management du Sport, Université de Bourgogne
2 Laboratoire de Psychologie, Santé et Qualité de Vie, Université Bordeaux 2

Age-related changes in adults have recently been shown to affect the process of visual word recognition. Older adults generally take longer to respond to words in the lexical decision task (LDT) than young adults. In addition, the inhibitory process of competition between lexical candidates (orthographic neighbourhood frequency and syllable frequency effects) has also been shown to be impaired in older adults. Several previous studies have shown that aerobic exercise can improve reaction times but not inhibitory mechanisms in older adults. This study aimed to investigate the influence of aerobic exercise on both reaction times and syllable frequency inhibitory effect in the LDT. The experiment consisted of a baseline session (LDT alone) and a moderate exercise session (walking + LDT). Forty older and 20 younger adults participated in the experiment. The results showed no inhibitory effects for older adults in the baseline session. More important, the beneficial effects of acute exercise were observed for half of the older adults. They displayed both shorter RTs and a syllable inhibitory effect. These data suggest that exercise, when it is effective, can improve the whole word recognition mechanism.

PS_3.004 - Online games training aging brains

van Muijden, J. 1, 2 , Band, G. P. 1, 2 , Colzato, L. 1, 2 & Hommel, B. 1, 2

1 Leiden University, Faculty of Social Sciences
2 Leiden Institute for Brain and Cognition (LIBC)

The number of people over age 65 is increasing rapidly worldwide. The social and economic consequences of large-scale cognitive aging have instigated increasing commercial and scientific interest in prevention and reduction of cognitive decline. The goal of our research is to understand individual differences in susceptibility to specific cognitive interventions. We have been developing custom brain training games for over two years. The games are partly inspired by commercially available brain training games, but specifically designed to tax executive functions. Transfer of training is typically assessed in a randomized controlled trial by means of an extensive cognitive test battery. Some limited transfer effects have already been found. The games were more effective as compared to quizzes in improving task set shifting, inhibition of automatic response tendencies and working memory updating (Van Muijden et al., in prep.). Moreover, the BDNF (brain-derived neurotrophic factor) Valine homozygous genotype was associated with a larger positive transfer effect to divided attention than the Methionine/-carrying genotype (Colzato et al., submitted). These findings support the notion that the success of cognitive interventions depends not only on the quality of an intervention, but also on the suitability of the intervention for an individual.

PS_3.005 - Aging and working memory: A time-based resource-sharing account

Gaillard, V.

Université Libre de Bruxelles

It is well-established that working memory capacity (WMC) declines with age. The present experiment investigates the mechanisms underlying this deficit in the context of the Time-Based Resource-Sharing model (Barrouillet et al., 2004). According to this model, the dual functioning of working memory is achieved through a mechanism of time-based resource-sharing between processing and storage. Young and older adults (aged 20-30 and 70-86) performed a computer-paced operation span task, in which they had to maintain series of letters while verifying 2-operands additions. We manipulated cognitive load in two conditions, depending on whether the additions require a carry (high cognitive load) or not (low cognitive load). Above and beyond the main effects of age group and cognitive load, results indicate that cognitive load has a more detrimental effect on recall in the older group. Implications for the development and aging of WMC are discussed.

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