Cognitive training enhances pre-attentive neurophysiological responses in older adults 'at risk' of dementia.
BACKGROUND
With predicted increases in dementia incidence, interventions targeting neuroplasticity and neuroprotection are required. Cognitive Training (CT) is an intervention which has been shown to improve aspects of cognition, but the pathophysiological mechanisms contributing to its efficacy are unknown.


OBJECTIVE
We aimed to explore the neurobiological correlates of CT using Mismatch Negativity (MMN), a neurophysiological marker of pre-attentive information processing, which in turn, is postulated to underpin higher-order cognitive processes.


METHODS
As part of a larger randomized controlled trial, forty 'at risk' (i.e., mild cognitive impairment or late-life depression) participants aged 51-79 years underwent neurophysiological, neuropsychological, and psychiatric assessments before and after a multi-faceted seven-week CT program or a 'treatment-as-usual' seven-week waitlist period.


RESULTS
The treatment group demonstrated significantly increased fronto-central MMN responses (p < 0.05), as well as improved phonemic verbal fluency (p < 0.05) and decreased self-rated memory difficulties (p < 0.05) following CT, in comparison to the waitlist control group. However, there were no significant correlations between enhanced MMN and cognitive/psychosocial outcomes.


CONCLUSIONS
Results from this preliminary investigation indicate that CT is associated with enhanced neurophysiological mechanisms suggestive of improved pre-attentive processing, which may reflect alterations in underlying neurobiology. Further research is warranted to confirm these findings, to explicate whether CT is associated with restorative or compensatory neuroplastic processes and to determine whether MMN is a useful biomarker for treatment response.
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia Department of Psychology, Macquarie University, NSW, Australia.
Loren
L
Mowszowski
Clinical Research Unit, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Daniel F
DF
Hermens
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Keri
K
Diamond
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Louisa
L
Norrie
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Nicole
N
Cockayne
School of Psychiatry, University of New South Wales, NSW, Australia.
Philip B
PB
Ward
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Ian B
IB
Hickie
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Simon J G
SJ
Lewis
Department of Psychology, Macquarie University, NSW, Australia.
Jennifer
J
Batchelor
Healthy Brain Ageing Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Sharon L
SL
Naismith
D000368:Aged; D000369:Aged, 80 and over; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000188:drug therapy / Q000534:rehabilitation*; D003265:Contingent Negative Variation / Q000187:drug effects / Q000502:physiology; D003704:Dementia / Q000188:drug therapy / Q000534:rehabilitation*; D003863:Depression / Q000175:diagnosis / Q000534:rehabilitation; D056344:Executive Function; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D008609:Mental Status Schedule; D008875:Middle Aged; D009483:Neuropsychological Tests; D013997:Time Factors; D014705:Verbal Behavior; D014706:Verbal Learning
D002800:Cholinesterase Inhibitors
Cognitive training; Mismatch Negativity; late-life depression; mild cognitive impairment; neurophysiological; neuropsychological