Education and Cognitive Functioning

Lars Nyberg

Umeå University

Sweden

Research on Aging at UmU

Ageing population Participation

Successful ageing

•Fertility•Mortality•Migration•Biologicalageing

•Work•Leisure•Social relations•Society•Image of ageing

•Health•Cognition•Economy•Network•Care

Interdisciplinaryresearch

Linnaeus database

Conceptualdevelopment

Ageing population Participation

Successful ageing

•Fertility•Mortality•Migration•Biologicalageing

•Work•Leisure•Social relations•Society•Image of ageing

•Health•Cognition•Economy•Network•Care

Interdisciplinaryresearch

Linnaeus database

Conceptualdevelopment

Ageing population Participation

Successful ageing

•Fertility•Mortality•Migration•Biologicalageing

•Work•Leisure•Social relations•Society•Image of ageing

•Health•Cognition•Economy•Network•Care

Interdisciplinaryresearch

Linnaeus database

Conceptualdevelopment

• Cross-faculty environment ”Aging and Living Conditions” (ALC)• One of 10 national ”Linnaeus” centra funded by the Swedish Research Council• Three main themes:

The Linnaeus DatabaseStatistics Swedenregister data

Inpatient and death cause data

VIPVästerbottencounty

BetulaUmeå

Geographical extension

Sweden Sweden Västerbottencounty

Umeå

Number of individuals

Total national population

Total national population

110 000 4200

Time coverage 1960 – 19901990 - 2005

1980s - 2006 1987, 19.. 1988, 19..

Time resolution 5 year (60 -90)Annual (90-05)

Continuous 5 year

Spatial resolution

100 meter squares

Kind of information

Socio-economic

Income

Family (links)

Work

Residence etc.

Hospital care

Death

Death cause

Health indicators

Life style

Living conditions

Socio-economic

Cognitive function

Health

Socio-economic

The Betula Study: A prospective study of aging, memory & health

Sample Wave 1

(1988-90)

Wave 2

(1993-95)

Wave 3

(1998-00)

1 N=1000

35-80 yrs

N=862 (86%)

40-85 yrs

N=730 (85%)

45-90 yrs

2 N=1000

35-80 yrs

N=684 (86%)

50-85 yrs

3 N=1000

40-85 yrs

N=829 (83%)

45-90 yrs

4 N=600

35-90 yrs

Wave 4(2003-05)

609 (83%)50-95 yrs

698 (84%)50-95 yrs

S5: 56335-95 yrs

Total of > 4200 participants

Two sessions

1. Health examination

- current & past health

- demographics

- subjective measures

- social variables

- critical life events

- personality- genetics (APOE, COMT)

2. Cognitive testing

Cross-sectional analyses

• Episodic: significant decline already at age 45• Semantic memory: significant decline after 55

Rönnlund et al (2005) Psych & Aging

N = 1959

Longitudinal analyses

• Episodic: significant decline at age 80• Semantic : significant decline at age 85

Practice-adjusted data*

* P = D - A Difference (D) = S1T2 – S2T2 = Attrition (A) + Practice (P) A = S1T1 (returnees) – S1T1 (whole group);

• Episodic: significant decline at age 65• Semantic : significant decline at age 80

Comparing longitudinal and cross-sectional data

Cross-sectional data ≠ Practice-adjusted longitudinal data

Influence of cohort differences in education on cross-sectional data?

EducationSelf-reported # years of formal education

Education-adjusted cross-sectional data

Identical pattern as practice-adjusted longitudinal data(significant decline in episodic memory 60-65 yrs)

Intermediate summary

Cohort differences in education account for disparity between cross-sectional and longitudinal trajectories across the adult age span -- control removes early onset of episodic

decline (35-60)

Substantial portion of the age-related variance remained after controlling

for education in the 5 oldest cohorts

Variability in cognitive aging

Most studies consider group-averaged cognitive changes-- less focus on distribution of individual scores =>=> Some elderly with a high level of functioning are ”hidden”

Inspired by Rowe and Kahn (1987) we used Q-mode factoranalysis to identify usual and successful aging on basis oflongitudinal change in performance across cognitive andnon-cognitive variables (Habib, Nyberg & Nilsson, 2007).

--usual vs successful: based on performance levels at two test sessions and change in levels across sessions

Sample composition

Middle age = 50-65 at T1; 55-70 at T2

Measures

Results

55 / 663 successful (8.3%) 25 / 403 successful (6.2%)

Variables defining usual vs.successful aging

Longitudinal analysis

51 of the 55 successful elderly at T1 were re-tested at T2

Of these 51, 18 (35%) were again classified as successful

352 of the 608 usual elderly at T1 were re-tested at T2

Of these 352, 345 (98%) were again classified as usual-- 7 (2%) were classified as successful (”positive reversal”)

Predictors of success over time:Successful-Successful (N=18) vs Successful-Usual (N=33)

• no difference on cognitive measures• one difference on non-cognitive measures; education (12.1 vs 9.6 years)

Neural correlates of success over time (Persson et al., 2006, Cerebral Cortex)

Stable & Decline groups well matched (N=20/20):• Age: 68.2 / 68.2• MMSE: 28.25 / 28.35• Female/male: 13/7 / 13/7• Education: 10.1 / 10.7

Participants from the Betula Study(selected from population of 1000 ss at T1)’Memory’ defined by 3 episodic tests

2002-03: MRI/fMRI-session

fMRI – categorization task (abs/conc) - left PFC activity for young adults (Wagner et al. 2000, Cer Cortex)

• Hippocampus volume• Diffusion Tensor Imaging (DTI)

Group differences: brain structure

Hippocampal volume

Anterior white matter integrity

Functional changesCategorization vs Rest

Overall analysis (N=40) revealed bilateral frontal activity

Atypical right frontal activity driven by declining elderly-- compensatory response?

Both groups showedtypical left PFC activity

Fostering positive reversals: Cognitive training

”Spontaneous” positive reversals rare (2%) => directed training

Several recent demonstrations that training can improveperformance on various executive tasks (e.g. working memory) - transfer / generalization of learning more difficult to show

Present study: updating training (Dahlin et al., 2008, Science; Dahlin et al., 2009, Psychology & Aging)

Training of updatingTime

FMRI I WEEK 1 WEEK 2 WEEK 3 WEEK 4 WEEK 5 FMRI IILM LMn-back n-backStroop Stroop

LV

M

31

4

Always memorize last 4 itemsVariable list length — 5-15 itemsAlso ”keep track” taskGraded training (3 levels; all at level 3 at week 5)Younger (15) and older adults in training groupControl group did fMRI I & IIExtensive transfer battery outside scanning18-month maintenance test session

Behavioral findings: criterion task

Substantial training effect in both groups

Significant long-term maintenance

Transfer

Speed-digit symbol

Working memory-computation span-digit span (F/B)-n-back (1/2/3)

Episodic memory-recall of nouns-paired associates

Semantic memory-letter fluence (FAS)-category fluency

Reasoning-Raven’s

Limited transfer effects-no significant transfer for elderly group-significant transfer to 3-back working memory of numbers for young (transfer effect maintained after 18 months)

FMRI findings: young adultsPre-training-- fronto-parietal activity for all 3 tasks-- striatal activity for LM & 3-back

Training-related changes--no common fronto-parietal changes--overlapping increase in striatum for LM & 3-back(No significant training-related fMRI changes on Stroop)

FMRI findings: older adults• Pronounced fronto-parietal activity during LM prior to training• No significant striatal activation during LM prior to training

• Training-related striatal increase for LM (cf., younger adults)• No training-related increase for 3-back

Variability within older group – those who showed transfer displayed striatal activation

Summary

• Substantial and durable training effects in both groups– Weak transfer effects

• More narrow view on process-region overlap– No support that a task-general fronto-parietal

system mediates transfer – Support that transfer rests on shared process

(updating) and related striatal brain system

Concluding points

• Education – substantial influence on ”cognitive profile” across the adult life span– Strong impact on slope for younger cohorts

• Education also explains some of the heterogeneity among older adults

• Neural changes additional factor– Hippocampus & striatum; ant. WM changes

• Functional compensation?

• Next step: Imaging at Betula T5– Brain x education interactions?