Cognitive Reserve (Week 11)

Cognitive Reserve

can be enhanced → actively combat damage.

defined in relation to processing efficiency.

flexible neural repsonses - same BR, but someone with more CR will tolerate greater damage before impairment apparent.

Brain Reserve

larger brains, more neurons = sustain more damage.

potential to be resilient, fucntion better for longer.

Threshold Model (Satz, 1993)

damage must exceed BR threshold to have visible effect. similar damage does NOT = similar impact.

• does not account for individual differences nor compensatory processing

• conceptualises BR very narrowly

Brain-Cognitive Reserve Interaction

CR active → dependent on development choices. individual differences (lifestyle factors) define age-related brain change and resilience.

BR passive → dependent on brain size, neuron count (uncontrollable - maximum limit). differences in brain structure define age-related brain change and resilience.

Experience-Induced Neuroplasticity

animal model evidence for experience induced neurogenesis (Kempermann et al., 2002).

cognitively stimulating activity can compensate damage in humans (May, 2011).

juggling intervention → daily trianing 3 months = increase grey matter at junction between temporal/occipital lobe (Draganski et al., 2004).

Neural Reserve

extent of ability to allocate neural reosurces, form new processing strategies, reslience when damaged.

integration of biological, genetics, psychological, social aspects (Barulli & Stern, 2013).

Influences of CR - Education

cognition in later life rpedicted by educational attainment (delays observable signs of pathology) (Jefferson et al., 2011).

linked to brain reserve markers (Liu et al., 2012). literacy + education standard more important.

bilingualism → attenuates cog. decline in AD; evidence of higher neural efficiency in bilinguals (Guzman-Velez & Tranel, 2015).

Influences of CR - Exercise

vascular physiology barrier to cog. decline after damage (Barnes, 2015).

(aerobic) exercise increases cerebral blood flow → promotes neurogenesis + cognitive performance (Davenport et al., 2012).

Influences of CR - Leisure

less impact of pathology with larger social networks (Crowe et al., 2003).

prevention of cog. decline w/ AD pathology acocunt for 14% variability in cog. change (Wilson et al., 2013).

Nun Study (Iacono et al., 2009)

idea density in autobiographies written by nuns at 22 yrs.

high idea density (literacy) = lack of cog. deficits w/ AD pathology. → neurons influenced by experiences.

greatest CR → advanced pathology at onset of observable decline. less time until pathology overwhelms function (hinders diagnosis).

CR - Limitations

• more details need on physiological supportive processes

• more longitudinal research needed - evidence largely retrospective

• lack of concrete measure of CR

Future Directions

• implement strats to maximise CR in those most at-risk

• increase education across lifespan

• person-centred training schemes

• cognitive screening of lower educated/poorer literacy for earlier detection of dementia