hasker p. davis 1 , tim curran 2 , and frederick keller 1

Development and Dissolution of Memory and Executive Function Across the Life

Span: Cognition from 5 to 90.

Hasker P. Davis1, Tim Curran2, and Frederick Keller1

University of Colorado at Colorado Springs1 and Boulder2

Empirical Findings

Verbal Memory

Rate of Forgetting for Verbal Information

Extent of Deficit for Verbal Memory

Visuo-Spatial Memory

Frontal Lobe Functioning Changes With Age

Theoretical Relationship Based on Neuropsychological Tests Between Frontal Lobe Functioning and Performance on Verbal Recall

Reduction of Cognitive Deficits

Tower of Hanoi Task

Object Recognition Task

Normal Performance on a Perceptual Skill by Elderly, Alzheimer’s Patients, and Amnesic Patients with MRI verified Hippocampal Damage

Verbal Recall (5 immediate trials and 20 min delay)

Trials

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1 2 3 4 5 20 min delay

Total N = 1453 range 99 to 201

Verbal Forgetting for Acquisition Matched Age Groups

Trials

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N range 17 to 65

5 20 Min Delay

REY RECALL AT 20 MINUTE DELAY FOR ACQUISITION MATCHED GROUPS

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30-45 years of age, n=1146-60 years of age, n=1461-75 years of age, n=1776-90 years of age, n=19

Trial 5 20 Minute Delay

Age condition significant at p=.013Delay significant at p=.001Interaction is not significant p=.26

REY RECALL AT 1 DAY FOR ACQUISITION MATCHED GROUPS

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30-45 years of age, n=1046-60 years of age, n=1661-75 years of age, n=2076-90 years of age, n=19

Trial 5 1 Day Delay

Age condition significant F(3,52) = 2.8, p = .047Delay significant F(1,52) = 107.3, p = .001Age by delay interaction was significant F(3,52) = 5.06, p = .004

Post-hoc pairwise comparisons showed that oldest group significantlydifferent from all other groups at the 1 day delay (76 to 90 year olds versus30 to 45, p=.022; versus 46 to 60, p=.003; versus 61 to75, p=.01). No group differences at the last immediate trial.

1-Day Delay (76-90 Years)

Number of Words Recalled

20-Minute Delay (76-90 Years)


Last Immediate Trial (76-90 Years)




















1 2 3 4 50 6 7 9 10 11 12 13 14 158

1514131211109876543210

1514131211109876543210

1514131211109876543210

1514131211109876543211514131211109876543210

1514131211109876543210

151413121110976543210 8

15141312111098765432101514131211109876543210

1514131211109876543210

151413121110987653210

Mean = 6.11Median = 5.0N = 35

Mean = 8.50Median = 9.0N = 40

Mean = 10.31Median = 10.0N = 29

Mean = 11.66Median = 12.0N = 32

Mean = 13.34Median = 14.0N = 32

Mean = 12.62Median = 13N = 29

Mean = 11.53Median = 12N = 40

Mean = 8.83Median = 9.0N = 35

Mean = 10.80Median = 11.0N = 35

Mean = 12.10Median = 12.0N = 40

Mean = 13.14Median = 13N = 29

Mean = 13.70Median = 14.0N = 32

Trial 1 (30-45 Years)


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Mean = 8.53Median = 8.0N = 32

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Number of Word Recalled

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Mean = 7.79Median = 8.0N = 29

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Mean = 5.72Median = 6.0N = 35

Visuo-Spatial Memory Cards Test

Visuo-spatial Performance Across the Life Span

Trials

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5 to 9 years old10 to 14 years old15 to 19 years old20 to 29 years old30 to 39 years old40 to 49 years old50 to 59 years old60 to 69 years old70 to 79 years old80 to 89 years old

1 2 3 4 5 Delay

Total N = 453 range 21 to 70

Conclusions: Verbal and Visuo-spatial Acquisition and Forgetting

1. Age effect on level of acquisition for verbal and visuo-spatial material.

2. No forgetting for any age group for visuo-spatial task.

3. Greater forgetting for youngest and oldest groups on verbal material.

4. Forgetting not a function of level of acquisition. Match on acquisition and age effect remains for verbal material.

5. Match task on forgetting. Greater forgetting for verbal material.

Tests of Frontal Lobe Functioning

1. Tower of London

2. Stroop Color-Word Interference

3. Wisconsin Card Sort Test

Total Excess Moves for the Tower of London

Age Groups

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Total N = 1249, Range 45 to 265

RED BLUE GREEN YELLOW



STROOP COLOR-WORD INTERFERENCE TEST

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WCST Categories Achieved

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Relationships Between Recall and Frontal Lobe Functioning

1. Frontal Lobe tests deficits as early as 40s.

2. Age effects on declarative tests by 50s.

3. Are there relationships between declarative memory and frontal lobe functioning. Detected small to moderate correlations for domains of recall, frontal , aging, and IQ. Moderate for stroop, recall delay, and aging.

4. Examine variables in covariate structural equation model.

Model Comparisons______________________________________________________

______________ Full Model Mediation Model____

Age Frontal .52(.05) .52(.05)

Age Recall .55(.47) ---------

Frontal Recall -1.81(.91) -.83(.12)

DF 12 13

X2 statistic 26.54 29.96

p-value .009 .005

GFI .953 .946

AGFI .890 .884

RMSR .067 .070

Reduction of Memory Deficits

1. Tower of Hanoi Performance and Deficit Reduction in the Elderly.

2. Reduction of Age-related Object Recognition Deficits.

TOWER OF HANOI PERFORMANCE AND AGE

SESSIONS (4 TRIALS/SESSION)

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ELDERLY CUEDELDERLY NOT CUEDYOUNG CUEDYOUNG NOT CUED

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TESTTRANSFER4321

TOWER OF HANOI PERFORMANCE

MethodMethod SubjectsSubjects

– Young, 18 - 25 years, n = 33

– Older, 60 - 76 years, n = 20

Yes/No Recognition Memory Test–– Studied Lists of Novel Visual ObjectsStudied Lists of Novel Visual Objects

–– Test Lists: Test Lists: 1/2 studied, 1/2 not studied objects1/2 studied, 1/2 not studied objects

–– Objects presented in HighObjects presented in High or Low Contrast or Low Contrast

High ContrastHigh Contrast Low ContrastLow Contrast

YoungYoung NormalNormal DegradedDegraded

OlderOlder EnhancedEnhanced NormalNormal

Normal StimuliNormal Stimuli Degraded

(80 Year Old Simulation)

Enhanced

(20 Year Old Simulation)

The figure is for example only. The stimuli suffered some degradation when imported into the presentation program and enlarged.

Test StimuliTest Stimuli

EEG Recording• 128 Channel Geodesic Sensor Net• During recognition memory test• Event Related Potentials (ERPs)

– ERPs are EEG averaged across trials in each condition.

– ERPs indextask-related brain electrical activity.

% Correct d' *Young Normal 72 1.23

Degraded 67 1.00

Older Normal 65 0.85Enhanced 68 1.00

R e c o g n i t i o n M e m o r y R e s u l t s

• Y o u n g : N o r m a l > D e g r a d e d , t ( 1 , 3 2 ) = 1 . 7 0 , p < . 0 5 .

• O l d e r : E n h a n c e d > N o r m a l , t ( 1 , 1 9 ) = 1 . 7 3 , p < . 0 5 .

* d ’ m e a s u r e s t h e a b i l i t y t o d i s c r i m i n a t e b e t w e e n s t u d i e d a n d n o t s t u d i e d o b j e c t s .

Memory-Related ERP Results• ERP Voltage Differences between

Studied & Not Studied Objects– 600 - 1500 ms after object onset– Right, Frontal Electrodes

• Young Subjects– Normal Contrast Only – Studied > Not Studied, F(1, 32) = 6.20, p < .05.

• Older Subjects– Enhanced Contrast Only– Studied > Not Studied, F(1, 19) = 4.70, p < .05.

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Institutionalized Elderly

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Conclusions

1. Elderly are impaired on verbal recall, there is increased age-related decline with increased delay, and age-associated memory impairment affects over 50% of the elderly.

2. Elderly are impaired on visuo-spatial memory. There is no age related forgetting over a 20 minute delay

3. There is an age-related relationship between forgetting of verbal material (temporal lobe function) and frontal lobe functioning.

4. Elderly deficit on the Tower of Hanoi is ameliorated with probes.

5. Amelioration of Elderly’s Deficit on Object Recognition occurs with enhanced contrast.

hasker p. davis 1 , tim curran 2 , and frederick keller 1

Documents

frontal recall

verbal material

age frontal

age recall

normal contrast high

young low contrast

declarative memory

visuospatial material