Cognition in aging

Cognition in Aging

Clifford Gonzales

CRNA, PhD

Cognition in Aging

• Identify cognitive functions

• List age-related changes in cognitive functions

• Identify activities promoting healthy cognitive functions

• POCD vs POD

• Name precipitating variables of POCD

• Strategies minimizing POCD

Cognitive Functions

• Working memory

• Processing speed

• Inhibition

• Sensory system

Working Memory

12 in

2mmhg/in

Working Memory

• Store= 12 in; 2mmhg/in

• Processing= 12 x 2= 24 mmhg

• Store= 24mmhg

• Look at current blood pressure= 100/65 mmhg

• Retrieve the 24mmhg

• Processing= 100-24 and 65-24= 76/41

• Compare 20% threshold

Cognitive Functions

• Working memory

• Processing speed

• Inhibition

• Sensory system

Inhibition

Sensory System

Cognition in Aging




• POCD vs POD



Age-Related Changes

• Brain atrophy= 0.35% per year @ 50 y/o1

• Ventricular hypertrophy= 2.9% per year @ 70 y/o2

• Hippocampal atrophy= ave of <1 % (26-82y/o)3

• Pruning of white matter

Age-Related Changes

• Mortimer JA, Snowdon DA, Markesberry WR. Neuropsychology. 20031

• Scarmeas N, Albert SM, Manly JJ, Stern Y. J Neurol Neurosurg Psychiatry. 20062

Cognitive Reserve Theory

Cognitive Reserve Theory

Clinical

Expression

of

Cognitive

Impairment

CNS lesions

White matter lesions

Brain atrophy

Plaques & tangles

Vascular damage

Metabolic/endocrine

diseases

Injury

Influencing factors

Genes

Lifestyle factors

(education,

occupation,social,

physical, & leisure

activities)

Brain size and function

Neural network

density and complexity

Processing capacity

and efficiency

Premorbid Cognitive

ability

Other influences

on cognitive impairment

prevention

Personality

Health service delivery

and uptake

Richards M, Deary IJ. Annals of Neurology. 20053

Cognition in Aging




• POCD vs POD



Healthy Cognitive FunctionsPhysical activity

150 min (moderate) or 75min (vigorous) aerobic + muscle strengthening

• Decrease sympathetic stimulation• Maintenance of brain structures4,5

Healthy Cognitive FunctionsLeisure Activity

• Activities more on life satisfaction

• Productive vs consumptive

• Effect on white matter6,7

• Associated with working memory, episodic memory, and processing speed.

Healthy Cognitive FunctionsSocialization

• Associated with working memory and processing speed8

Cognition in Aging




• POCD vs POD



Cognitive Impairment

• Postoperative delirium- acute fluctuation of the state of orientation and attention.

• Postoperative cognitive dysfunction- alteration in learning, memory, abstract thinking, and concentration after surgery.

Cognition in Aging




• POCD vs POD



Postoperative Cognitive Dysfunction

• Predisposing factors:

Age

Co-morbidities: presence of cognitive impairment

• Precipitating factors

Stress

Cell injury

Stress

Cell Injury

• Precursors of Alzheimer’s dse

• Inflammatory markers/receptors

Alzheimer’s Dse

Temperature induced

Inflammatory Markers/Receptors

• Microglial activation-release of TNF-a

• NMDA receptors-protein changes lead to spatial learning impairment

Neuroprotection vs Neurotoxicity

• Type of surgery

• Type of anesthesia

RA vs GA

Volatile vs intravenous

Isoflurane vs Desflurane vs Sevoflurane

• Number of exposure to anesthesia

Type of Surgery

• Evered 2011- RCT, 644 participants

RA vs GA

• Mason 2010: systematic review with meta-analysis, 21 studies.

• Mandal 2011: RCT, 60 participants, GA vs EA.

Volatile vs Intravenous

• Chen 2014, retrospective, secondary analysis, 26,725 Taiwanese

Iso vs. Des vs. Sevo

• Ye 2013. Cell culture. Use of Iso, sevoflurane, and propofol

• Zhang 2012. Pilot study, 15 per group, Isoflurane, desflurane.

Reasons for Various Results

• Different neuropsychological tests

• Different design and methodology

Cognition in Aging




• POCD vs POD



Strategies

• Preoperative screening

• Hemodynamic monitoring- is 20% BP threshold is applicable for older adults?

• Monitor oxygenation and ventilation

• Temperature regulation

• Use of BIS monitor

References

1. Mortimer JA, Snowdon DA, Markesberry WR. Head circumference, education, and risk of dementia: Findings from the Nun study. J Exp Psychol. 2003; 25(5): 671-679.

2. Scarmeas N, Albert SM, Manly JJ, Stern Y. Eudcation and rates of cognitive decline in incident of Alzheimer’s disease. J Neurol NeurosurgPsychiatry. 2006; 77:308-316

3. Richards M, deary IJ. A life course approach to cognitive reserve: a model for cognitive aging and development. Annals of Neurol. 2005;58(4):617-622

4. Colcombe SJ, Erickson KI, Raz N, et al. Aerobic fitness reduces brain tissue loss in aging humans. J Gerontol A. 2003; 58(2): 176-180

5. Erickson KI Prakash RS, Voss MW, et al. Aerobic fitness associated with hippocampal volume in elderly humans. Hippocampus. 2009; 19(10): 1030-1039.

6. N. A. Dennis and R. Cabeza, “Neuroimaging of healthy cognitive aging,” in Handbook of Aging and Cognition, F. I. M. Craik and T. A. Salthouse, Eds., pp. 1–54, Psychology Press, New York, NY, USA, 3rd edition, 2008.

7. Sullivan EV, Pfefferbaum A, Adalsteinsson E, Swan GE, Carmelli D. Differential rates of regional brain change in callosal and

ventricular size: a 4-year longitudinal MRI study of elderly men. Cereb Cortex. 2002; 12(4): 438-45

8. Bigler ED, Blatter DD, Anderson CV, Johnson SC, Gale SD, Hopkins RO, Burnett B. Hippocampal volume in normal aging and traumatic brain injury. AJNR. 1997; 18: 11-23.

9. Saczynski JS, Jonsdottir MK, Sigurdsson S, Eiriksdottir G, Jonsson PV, Garcia ME, et al. White matter lesions and cognitive performance: the role of cognitively complex leisure activity. J Gerontol A Biol Sci Med Sci. 2008; 63(8): 848-854.

10. Gow AJ, Bastin ME, Phil D, Maniega SM, Hernandez V, Morris Z, Murray C, et al. Neuroprotective lifestyles and aging brain. Neurology.2012;79(17): 1802-1808.

11. Ybarra O, Burnstein E, Winkielman P, Keller M, Mannis M, Chan E, Rodriguez J. Mental exercising through simple socializing: social interactions promotes general cognitive functioning. Pers Soc Psychol Bull. 2008;34(2): 248-259.

12. Xiao-dong Z. Mei-hua P, Yan-shu W, Chun-sheng F. Influence of sub-anesthetic dose of ketamine and dexmedetomidine on early postoperative cognitive dysfunction in elderly orthopedic patients under total intravenous anesthesia. Journal of Jilin University. 2013

Thank you!

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Cognition in aging