Preliminary findings for intact sympathetic, but impaired central nervous system novelty processing in older adults with amnestic mild cognitive impairment
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1
Western Sydney University, NICM, Australia
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2
University of Wollongong, Brain & Behaviour Research Institute and School of Psychology, Australia
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3
Western Sydney University, School of Medicine, Australia
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4
University of Sydney, Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, Australia
Aims: Amnestic mild cognitive impairment (MCI) is conceptualised as the prodromal stage for Alzheimer’s disease. In addition to memory deficits, people with amnestic MCI often demonstrate impairments in multiple domains such as learning and attention. The orienting reflex (OR) is a fundamental learning mechanism that directs an organism’s attention towards novel stimuli. This study examined OR changes in novelty processing with the aim of highlighting mechanisms underpinning learning-related pathophysiology in MCI due to Alzheimer’s disease.
Method: Sixteen adults with amnestic MCI (determined using the NIA-AA core clinical criteria for MCI due to Alzheimer’s disease) completed an auditory dishabituation task whilst their electrodermal and 64 channels of electroencephalographic (EEG) activity were recorded. Two conditions (count vs. no count) were presented in a counterbalanced order; stimulus sequence: 10 standards, 1 deviant, 2 – 4 standards. Single trial skin conductance responses (SCRs) and event-related potentials (ERPs) were extracted for each subject and condition, and ERPs were submitted to temporal PCA. Response decrement, recovery, and dishabituation were assessed.
Results: SCR showed the typical response decrement, recovery, and dishabituation previously established in younger adults; response recovery and dishabituation were greater for the count than no count condition. Similarly, fronto-central N1-1, and central-left PN showed decrement, recovery, and dishabituation that was greater for count compared to no count stimuli. A parietal P3 component resembling novelty P3, but occurring between P3a and P3b, showed response decrement, recovery, and dishabituation, with greater dishabituation to count than no count stimuli.
Conclusions: These preliminary results demonstrate that the sympathetic OR is intact in older adults with amnestic MCI. Response patterns in N1-1 and PN are unlike those reported previously in younger adults and may reflect pathophysiological changes in central learning and attention mechanisms. Future work will employ a larger sample and explore these preliminary findings further by comparing them against age and gender matched controls.
Acknowledgements
This research was supported by funding from a National Health and Medical Research Council (NHMRC)-Australian Research Council (ARC) Dementia Research Development Fellowship (GNT1102532).
Keywords:
mild cognitive impairment (MCI),
habituation,
Orienting reflex (OR),
skin conductance response (SCR),
event-related potentials (ERPs)
Conference:
ASP2017: 27th Annual Meeting for the Australasian Society for Psychophysiology, Parramatta, Australia, 29 Nov - 1 Dec, 2017.
Presentation Type:
Poster Presentation
Topic:
Abstract (General)
Citation:
Steiner
GZ,
Karamacoska
D,
Fogarty
JS,
Fagan
NL,
Hohenberg
MI and
Grieve
SM
(2019). Preliminary findings for intact sympathetic, but impaired central nervous system novelty processing in older adults with amnestic mild cognitive impairment.
Conference Abstract:
ASP2017: 27th Annual Meeting for the Australasian Society for Psychophysiology.
doi: 10.3389/conf.fnhum.2017.224.00003
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Received:
02 Nov 2017;
Published Online:
25 Jan 2019.
*
Correspondence:
Dr. Genevieve Z Steiner, Western Sydney University, NICM, Penrith, NSW, 2751, Australia, g.steiner@westernsydney.edu.au