A Program of Research Examining the Cognitive Correlates of Methamphetamine Abuse.

Cognitive Battery

• Broad in Scope

• Probes Simple Effects

– or

• Uses Instruments Known to Tap Specific Effects

__________________________

• Several Studies

• N’s will be reported

• Comparison Groups do not differ in:

– Age

– Gender

– Education

– Ethnicity

Memory Tests

• Word Recall

• Picture Recall

• Word Recognition

• Picture Recognition

• Backward Digit Span

Perceptual Speed and Manipulation of Information

• Digit Symbol

• Trail Making A

• Trail Making B

Other Instruments• Ability to Ignore Irrelevant Information

• Stroop

• Short Form IQ • Shipley-Hartford Vocabulary • Shipley-Hartford Abstract Thinking

• Verbal Fluency • FAS

• Abstract Reasoning • WCST

First Question

Are there cognitive deficits in individuals currently abusing methamphetamine?

Perceptual Speed and Manipulation of Information

N= 65 per group

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10

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40

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60

70

80

Digit Symbol Trails A Trails B

MAComparison

*

*

Ability to Ignore Irrelevant Information - Stroop Test

N = 65 per group

0

1020

3040

5060

7080

90100

Words Colors Color-Words

MAComparison

*

Memory TestsN = 65 per group

0

5

10

15

20

25

Word

Rec

all

Pic

ture

Rec

all

Word

Rec

ogn

itio

n

Pic

ture

Rec

ogn

itio

n

MA

Comparison

* *

Short Form IQN= 65 per group

0

5

10

15

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25

30

Vocabulary Abstract Thinking

MAComparison

*

Other Measures

• Verbal Fluency

• FAS NS

• Working Memory for Digits

• Backward Span NS

• Abstract Thinking

• WCST NS

Second Question

Are the deficits found in current methamphetamine abusers associated with the amount, pattern, frequency or length of use?

Associations with Cognitive Deficits

N = 90 MA Abusers

• No Association was found for• Length of Use• Age• Family History• Medical History• Gender• Route of Administration

Association with Cognitive Deficits

N = 90 MA Abusers

• Frequency of Use Predicts:

– Recall p=.02

– Recognition p=.02

– Word p=.01

– Picture p=.02

– Stroop Interference p<.01

– Digit Symbol p=.02

Third Question

Are the same deficits found for current abuse of other stimulants such as cocaine?

Comparison of Cognitive Performance of Current Abusers of

MA and Cocaine• N = 160

• Four groups of 40

• MA

• MA comparison

• Cocaine

• Cocaine comparison

MA vs. CocaineMeasure MA Comp Coc. Comp

Vocabulary 26.6 30* 24.7 28*

Abstract Thinking 11.5 16** 10.6 13.6*

Digit Symbol 53 66** 51 56

Trails A 32 27** 36 31

Trails B 81 62** 87 70

Stroop CW 39 46** 36.6 40.3*

Word Recall 3.1 6.2* 2.5 4.2**

Picture Recall 5.5 6.7 5.0 6.7**

Difference on Word Recognition for groups with Wender Scores >46

& <46

Mean Word Recognition

WURS>46 12.7

WURS<46 15.2 (t80=2.04, p=.04)

Effect of Childhood ADHD as Measured by the Wender Utah

Rating Scale• WURS Score does not predict cognitive

performance.

• WURS Score >46 = Probable ADHD

• 83 Currently Using MA Abusers were divided into two groups: >46 (N=25) and > 46 (N=58).

Differences on WCST between Probable ADHD and Comparison

Groups>46 Comparison

Categories 4.76 5.67 *

Total Errors 28.4 17.9 *

Perseverative 14.4 9.11 *

Nonperseverative 14.0 8.81 *

% Conceptual Level 67.0 77.6 *

Failure to Maintain Set 1.04 0.47 *

<46 vs. Comparison NS on all Measures

Fourth Question

What is the duration of the deficits after use stops?

Memory 0 - 3 Months

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5

10

15

20

25

Word Recall PictureRecall

WordRecognition

PictureRecognition

Comparison

1-7 days

3 Months

N=22

Ability to Ignore Irrelevant Information 0 - 6+ Months

41

4243

4445

4647

4849

5051

Color-Words

ComparisonPositive3 Months6 Months6+ Months

Cross Sectional Data

Manipulation of Information and Perceptual Speed 0 - 6

Months

0

10

20

30

40

50

60

70

80

Digit Symbol Trails Trails B

Comparison1 - 7 days3 Months6 Months

N = 7

Memory 0 - 6 Months

0

5

10

15

20

25

Word Recall PictureRecall

WordRecognition

PictureRecognition

Comparison1-7 days3 Months6 months

N=7

Manipulation of Information and Perceptual Speed 0 - 6+

Months

0

10

20

30

40

50

60

70

80

Digit Symbol Trails Trails B

Comparison1 - 7 days3 Months6 Months6+ Months

Cross Sectional Data

Manipulation of Information and Perceptual Speed

0

10

20

30

40

50

60

70

80

Digit Symbol Trails A Trails B

Comparison1-7 Days3 Months

N = 22

Memory 0 - 6 Months Cross Sectional Data

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5

10

15

20

25

Word Recall PictureRecall

WordRecognition

PictureRecognition

ComparisonPositive3 Months6 Months6+ Months

Work Planned and in Progress:Further Questions

Questions about Memory

• Is the problem for abusers task difficulty or verbal material?

• Does the problem exist for Semantic as well as Episodic Memory?

• Is Implicit Memory Effected?

• Is Working Memory Effected?

Questions about Memory Continued

• What memory process(s) are affected? – Encoding– Rehearsal– Retrieval

Does the problem exist for Semantic as well as Episodic Memory?

• No

• We found no difference between MA abusers and the comparison group on Shipley-Hartford Vocabulary and FAS. Both of these are tests of Semantic Memory.

Is Implicit Memory Effected?

Preliminary analyses suggest that Implicit Memory is not affected in MA abusers.

MA Comparison

Word Fragment Words 3.8 4.3

Total Words 7.6 10.2

N (MA=17, Comparison=14)

Is Working Memory Effected?

Results from our tests of working memory

are not consistent.

MA Comparison

Missing Digit 7.52 6.92

Sentence Span 1.9 2.4*

N (MA=17, Comparison=14)

Questions About Attention

• How pervasive are problems with attention?

• If attention is a problem, how long does the problem last?

• Do deficits in attention account for some of the problems with memory?

Questions about Executive Function

• Are there deficits found on tasks that are associated with a specific area of the prefrontal cortex?

• Is the score on the measure of childhood ADHD associated with performance on tasks tapping executive function?

Word Recognition

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1-7 days 3 months 6 months

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1-7 days 3 months 6 months

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Word Recall