ATTENTION AND ADHD

134 Pages·2014·0.69 MB·English

ATTENTION AND ADHD: MEASUREMENT AND MEDICATION

by

Kimberly Blair Saliba

A thesis submitted in conformity with the requirements
for the degree of Doctor of Philosophy
Graduate Department of Applied Psychology and Human Development
Ontario Institute for Studies in Education
University of Toronto

© Copyright by Kimberly Blair Saliba 2014
Attention and ADHD: Measurement and Medication
Kimberly Blair Saliba
Doctor of Philosophy
Graduate Department of Applied Psychology and Human Development
Ontario Institute for Studies in Education
University of Toronto
2014
Abstract
The chronic and severe attention difficulties experienced by adults with Attention-
Deficit/Hyperactivity Disorder (ADHD) are well documented in terms of their behavioral
manifestations (e.g., disorganization, distractibility, hyperactivity, etc.). By contrast, the precise
nature of the underlying cognitive manifestations of inattention remains elusive and the effects of
long-acting stimulant medication on cognition attention are even less clear.
Study 1. Investigated the validity of the computation method for calculating the attention
network scores, as measured by the ANT paradigm, as well as its test-retest reliability (e.g.,
across test-retest intervals of several hours as well as across an interval of two weeks). Twenty
adult participants with ADHD (2 females, 18 males) aged 21-65 (M=39.50, SD=10.83) were
administered the ANT seven times across different time frames (evening, morning, and ranging
from hours to 2 weeks). A strong relationship was found between flanker or cue conditions used
to compute network scores. Test-retest reliability of the orienting network reaction time scores
was adequate in adults with ADHD, and that for the executive network was moderate across all
conditions. By contrast, the alerting network scores revealed adequate reliability across a short
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time frame (6-8 hours, relatively unpracticed), but lower reliability in well-practiced
performance.
Study 2. Thirty adult participants with ADHD (2 females, 28 males) aged 21-65
(M=42.20, SD=11.32) completed the ANT four times in an 18-hour period (at hours 0, 8, 11, 15
post-ingestion) on two occasions about 2 weeks apart, in a randomized, double-blind, crossover
placebo-controlled trial of a novel long-acting stimulant medication (Multilayer-Release-
Methylphenidate; MLR-MPH). MLR MPH had no effects on the efficiency of the ANT networks,
nor on overall reaction times (RT). However, at Hour-8 (i.e., after 2nd peak release; 3:30pm-
5pm) participants’ RTs were significantly less variable when receiving MLR-MPH compared to
placebo.
Conclusion. ANT performance scores (response times, accuracy) showed low to
adequate test-retest reliability across various time frames and practice in a clinical sample of
adults with ADHD. Specifically, the alerting network scores had lower reliability. The long-
acting stimulant medication, MLR-MPH enhanced performance consistency (as indexed by
intra-individual variability of RTs) during its extended period of release (i.e., 8-11 hours post
ingestion).

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Acknowledgements
During my long, tumultuous journey in obtaining my PhD, I encountered several set backs – I
felt bewildered at times, and then also from time to time I felt glimmers of excitement and hope.
Through it all, my mentor and supervisor, Dr. Rosemary Tannock, challenged me to think
beyond the scope of the data and she encouraged me to think critically about my research, which
internally pushed me to find inner strength and fortitude to persevere. I whole-heartedly
contribute my PhD thesis completion to all the incredible support and dedication Rosemary has
given to me over the years. I will always forever cherish her expert guidance.

I would also like to thank my committee members, Dr. Umesh Jain and Dr. Laura Janzen. Umesh,
I thank you for going out of your way to accommodate me in scheduling and meeting with all the
different participants and completing the surmountable necessary paperwork. Above all, I value
your sense of humor during the countless times I needed it most. Laura, I want to thank you for
your diligence in thoroughly reading my thesis numerous times, providing me with feedback,
and support.

To my parents, you both hold education as such a high regard and value the importance of
learning. Mom, your love has made it possible for me to get through all the life journeys I had to
endure during my PhD. Dad, your love and support have always been constant but above all, you
have taught me to never back down from intimidating/educated people. To my uncle Lenny, you
have always made me feel so very special and loved, thank you.

To my siblings, John, Melissa, and Teri – all three of you are my constant sounding board and
rock. John, thank you for always carrying the conversation, looking up to me and believing in me,
and making me laugh. Ter, thank you for loving me the way you do and being able to constantly
provide sound judgment/logic and reason – this always helps me make a sound decision. Missy, I
know I can always count on you, I value that I can rely on you to provide me with your
undivided attention, your jokes, and your love. My life experiences are completely enriched
because I have each one of you to be there with me, whether it’s in my heart, a phone call away,
or in person. Thank you for believing in me and supporting me throughout my entire schooling
journey.

To the Saliba family, Mary and Vince you two truly are the kindest and selfless people I know.
Your love and support touches my heart behind words. To Vinnie, Sonya, and Jackie – Son,
thank you for editing my papers, your wordsmith abilities are phenomenal. Jack, your kind,
sensitive wellbeing and encouragement mean the world to me. Vinnie thank you for inner
encouragement and belief in me.

Lastly, to my loving husband, Paul- I began my schooling journey with you 14 years ago. We
have gone through not only life events together but also all the trials and tribulations that come
with me being a student for so long. You never allowed me to give up, you always wanted the
best for me every step of the way even when things looked bleak on so many different levels.
You pushed me when I didn’t think I had it in me any more. If I could, I would give half this
degree to you, as you deserve it for so many reasons that I hold very dear to me. I truly adore you
and love you so very much, thank you for being my life partner.
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Table of Contents
Abstract ii
Acknowledgements iv
List of Tables and Figures vii
List of Appendices ix

CHAPTER ONE: Rationale and Overview of Dissertation Research 1
1.1 Overview of Thesis 2
1.2 ADHD in Adults: Clinical Manifestations 4
1.3 ADHD in Adults: Cognitive Manifestations 6
1.4 Models and Measurements of Attention 7
1.4.1 Models of Attention 7
1.4.2 Attention Network Measurement 12
1.5 Pharmacological Treatment of ADHD 17
1.5.1 Neurochemistry of ADHD 17
1.5.2 Stimulant Medication 17
1.5.3 Stimulant Effects on Behavioral Symptoms 18
1.5.4 Stimulant Effects on Cognitive Attention Tasks 19
1.5.5 Stimulant Effects on Attention Network Test 20
1.6 Rational, Objectives, Hypotheses, and Outlines of Studies 22
CHAPTER TWO: Psychometric Properties of the ANT (prepared manuscript) 27
2.1 Abstract 28
2.2 Introduction 29
2.3 Method 32
2.3.1 Participants 32
2.3.2. Material and Procedures 33
2.3.3. Data Analyses 35
2.4 Results 38
2.5 Discussion 40

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CHAPTER THREE: The Effects of Long-acting Stimulant on Cognitive
Attention in ADHD (prepared manuscript) 55
3.1 Abstract 56
3.2 Introduction 58
3.3 Method 61
3.3.1 Participants 61
3.3.2 Material and Procedures 62
3.3.3. Data Analyses 66
3.4 Results 67
3.4.1 Baseline: Group Equivalency 67
3.4.2 Effects of MLR-MPH During the Extended Release Period 68
3.4.3 Effects of MLR-MPH on Task Performance Within Each Hour 70
3.4.4 Supplemental Quantitative Analyses 72
3.5 Discussion 72
CHAPTER FOUR: Conclusions and Implication 86
4.1 Summary of Findings 87
4.1.1 Validity of the Traditional Approach for Calculating ANT scores 88
4.1.2 Robustness of the ANT 89
4.1.3 MLR MPH Effects on the ANT 90
4.1.4 MLR MPH Effects on Performance with Each Hour 95
4.1.5 MLR MPH Effects on Arousal 95
4.3 Study Limitations and Strengths 96
4.4 Implications for Clinical Practice 99
4.5 Theoretical Implications 100
4.6 Future Directions 101
4.7 Conclusion 102
CHAPTER FIVE: Supplemental Section 104
References 118

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List of Figures and Tables
Chapter 2
Table 1. Descriptive Statistics for Demographic Information 45
Table 2. Novel ANT Analyses of the Alerting and Orienting Network Scores,
as a Function of Flanker Condition and Time (Visit 3, Visit 4) 46
Table 3. Novel ANT Analyses of the Executive Network Scores, as a Function of
Cue Condition and Time (Visit 3, Visit 4) 47
Table 4. Correlational ANT Analyses of the Network Scores, as a Function of Cue
and Flanker Condition 48
Table 5. Short-Term Test-Retest Reliability of the ANT, Using Conventional
Computational Approach, as a Function of Practice
(Short-Term Unpracticed/Practiced) and Method for Calculating
Mean RT (Untrimmed v. Trimmed) 49
Table 6. Longer-Term (Two-week) Test-Retest Reliability of the ANT, Using
Conventional Computational Approach, at Hour 0, as a Function
of Practice (Visit 3 vs. Visit 4) and Method for Calculating Mean
RT (Untrimmed vs. Trimmed) 50
Table 7. Test-Retest Correlational Reliability of the ANT, Using
Conventional Computational Approach, as a Function of Time (Short/Long),
Practice (Practiced/Unpracticed), and Method for Calculating Mean RT
(Untrimmed vs. Trimmed) 51
Figure 1. Schematic of the Attention Network Test 52
Figure 2. Operational Network Computation for Conventional ANT Analyses 53
Figure 3. Participants Visit Procedures 54

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Chapter 3
Table 1. Descriptive Statistics for Demographic Information by Drug Order Sequence 76
Table 2. Analyzing Group Equivalency at Baseline at Hour 0 at, Visit 3 and Visit 4 77
Table 3. Mean RT and Variability in Mean RT for correct response of Attention
Network Scores on the ANT across the day, as a function of Hour 78
Table 4. ANT analyses of Mean RT and Variability in Mean RT of Network
Scores Across the Day, as a Function of Drug, Hour, and Order 79
Table 5. Mean RT and Variability in Mean RT Scores on the ANT Within
Each Hour, as a Function of Block 80
Table 6. ANT Analyses of Mean RT and Variability in Mean RT Scores for
Correct Responses Within Each Hour, as a Function of Drug, Block and Order 81

Figure 1. Participants Visit Procedures 82
Figure 2. Schematic of the Attention Network Test 83
Figure 3. Operational Network Computation for Conventional ANT Analyses 84
Graph 1. Interaction of Drug by Order of the Overall Mean and Executive
Functioning Network RT Scores 85

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List of Appendices
Page
Supplemental
Method: Description of Data Analyses for Novel Method 104
Table 1: Novel ANT Analyses of Alerting Variables, as a Function of 106
Time and Visit
Table 2: Novel ANT Analyses of Orienting Variables, as a Function of 107
Time and Visit
Table 3: Novel ANT Analyses of Executive Variables, as a Function of 108
Time and Visit
Table 4: Test-retest correlational reliability of conventional ANT analyses, 109
as a Function of Time and Method for computing Mean
Table 5: Operational Network Computations for Novel ANT analyses 110
Table 6: Participants’ Self Report in Identifying when on Drug and Placebo 111
Table 7: Participants’ Self Report in Identifying when on Drug and Placebo 112
for Both Visits, as a Function of Drug Order
Table 8: Participants’ Self-Report Symptomology 113
Table 9: Potential Methylphenidate Side Effects/Risks 114
Section 10: Inclusion/Exclusion Criteria 115
Section 11: Screening Evaluation 117

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1

CHAPTER ONE

Rationale and Overview of Dissertation Research