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Electrophysiological Correlates of Attentional Dysfunction in Dementia with Lewy Bodies

Lookup NU author(s): Dr Ruth Cromarty, Dr Sara Graziadio, Dr Sean Colloby, Alison Killen, Dr Luis Peraza Rodriguez, Dr Greg Elder, Dr Michael Firbank, Professor Alan Thomas, Professor Ian McKeith, Professor John O'Brien, Dr John-Paul Taylor

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Abstract

Background: Dementia with Lewy bodies (DLB) is characterised by attentional impairmentsalthough the underlying aetiology is poorly understood. Using electrophysiological approaches, weinvestigated the extent to which attentional network efficiency was differentially affected in DLBpatients (n=22) relative to Alzheimer’s disease (AD) patients (n=24) and age-matched healthycontrols (n=19) by using a modified version of the Attention Network Test (ANT). The ANT, avisual attention task, probes the efficiency of three anatomically defined attentional networks:alerting, orienting and executive-conflict. Methods: Participants completed the ANT whilstundergoing high-density electroencephalography (EEG) recordings (128 channels). Timefrequencywavelet analyses were conducted to investigate event-related spectral perturbations(ERSP), between 4-90Hz, in the 500ms after stimuli presentation. Attentional network ERSP wascalculated by contrasting oscillatory reactivity following relevant stimuli, and repeated-measures(time x region) ANOVAs were conducted with a between-subject factor of group (controls, AD,DLB). Results: For the alerting network, the DLB group exhibited attenuated ERSP in the lowerfrequencies (< 30Hz); in the theta range (4-7Hz) the controls and AD group showed globalsynchronisation (across all regions), peaking at approximately 300ms, which was absent in theDLB group. Lack of DLB theta synchronisation between 250-450ms over the right parietal cortexassociated with a higher total score on the Clinical Assessment of Fluctuation scale. ERSPassociated with the orienting and executive networks was comparable across all groups,comprising intermittent synchronisation of reduced power relative to the alerting network, whichwas diffuse across the time and frequency domains in all regions. Conclusions: Attenuated globaloscillatory reactivity in the DLB group specific to the alerting network is indicative of thisfractionated aspect of attention, the ability to maintain an alert state, being differentially affected inDLB. Lack of theta reactivity in the right parietal region may be a potential contributor to thepathophysiology of cognitive fluctuations in DLB.


Publication metadata

Author(s): Cromarty R, Graziadio S, Colloby S, Killen A, Peraza LR, Elder G, Firbank M, Thomas A, McKeith I, O'Brien J, Taylor J-P

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: International Dementia with Lewy Bodies Conference 2015

Year of Conference: 2015

Pages: 155-155

Acceptance date: 01/11/2015

ISSN: 2165-591X

Publisher: American Journal of Neurodegenerative Disease

URL: http://www.ajnd.us/files/International_Dementia_With_Lewy_Bodies_Conference_Abstracts_DWD_11_22_15.pdf

Notes: Poster P.101 page 155


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