Student1Presentation2019Sp11.pptx

The MRI Race: Brain Volume Deficiency in individuals with ADHD

Student Presenter

Department of Biology, East Central University

19 April 2019

Introduction roadmap

Background

What Is ADHD?

The MRI Race and Why We Care

Paper Citations

Papers

Paper #1

Paper #2

Paper #3

What is ADHD?

Single most common mental disorder affecting children1

5% of all children

2.5% of all adults

Characterized by: Inattention, hyperactivity, and impulsivity

(1) American Psychiatric Association

Stanford Medicine 2015 (image)

ADHD is caused by a wide variety of things. These include problems during pregnancy, premature birth, genetics, and some other things that scientists are still trying to figure out. ADHD is the single most common mental disorder affecting children, affecting 5% of all children and 2.5 percent of adults. ADHD is characterized by inattention, hyperactivity, and impulsivity.

I originally studied ADHD in my honors thesis. As a future developmental pediatrician I will diagnose and treat ADHD more than any other disorder. I have always been interested in the neurobiology behind ADHD, but using MRI to learn more about the specific structures and areas affected will benefit the future patients I look forward to serving.

The MRI race and why we care

Using MRI to visualize brain volumes:

Unique insight into ADHD brain volume deficiencies

National Institute of Mental Health 2007 (image)

Now we need to talk about the neurobiology of ADHD. Research shows that brains of those with AHD develop at a normal rate but is delayed by an average of three years in certain brain regions. If you look at this picture you can see that certain brain structures are delayed between the important ages of 7 and 13. For example the frontal cortex is delayed. The frontal cortex controls thinking, planning, and attention. All behaviors that are associated with ADHD.

Paper citations

Paper #1:

Hoogman M, Bralten J, Hibar DP, Mennes M, Zwiers MP, Schweren L, van Hulzen KJE, Medland SE, Shumskaya E, Jahanshad N, et al. Subcortical brain volume differences of participants with ADHD across the lifespan: an ENIGMA collaboration. The Lancet Psychiatry. 2017 Feb 16:1–39.

Paper #2:

Castellanos, F. X.; Lee, P. P.; Sharp, W.; Jeffries, N. O.; Greenstein, D. K.; Clasen, L. S. Developmental Trajectories of Brain Volume Abnormalities in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder. Jama 2002, 288, 1740.

Paper #3:

Batty MJ, Liddle EB, Pitiot A, Toro R, Groom MJ, Scerif G, Liotti M, Liddle PF, Paus T, Hollis C. Cortical Gray Matter in Attention-Deficit/Hyperactivity Disorder. Journal of the American Academy of Child & Adolescent Psychiatry. 2010;49(3):229–238.

____ = date of publication

Paper #1: SubCortical Brain Volume Differences of Participants with ADHD Across the Lifespan: an ENIGMA Collaboration

Mega-analysis

1713 cases (ADHD)

1529 controls

Hoogman et al. 2017

Cliff Notes:

Size deficiency in all regions tested except the pallidum and thalamus

Psychostimulant medication & symptom severity: no effect on size

Paper #2: Developmental Trajectories of Brain Volume Abnormalities in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder

Castellanos et al. 2002

152 cases (ADHD)

139 controls

Cliff Notes:

1. Stimulant medication increases volumes of all structures tested, but not at levels similar to controls

Paper #3: Cortical Gray Matter in Attention-Deficit/Hyperactivity Disorder: A Structural Magnetic Resonance Imaging Study

25 cases (ADHD)

24 controls

Cliff Notes:

Statistical deficit of the pars opercularis cortex

Hypothesis supported

Batty et al. 2010

Pars opercularis because of its connection to inhibitory control, a facet of ADHD behavior.

Analysis roadmap

Introduction

Methods

Results

Discussion

Overview

Introduction

Paper #1

Pros:

Framing the problem and objectives in separate subsections

Paper #2

Pros:

Detailed literature review

Paper #3

Pros:

Good mix of subject and literature review

Cons:

Missing a hypothesis

Cons:

Abstract skimpy in context and methods; heavy in results

Cons:

Title is general

Methods

Paper #1

Pros:

Repeatable description of overall experiment

Paper #2

Pros:

Repeatable patient gathering/ screening

Paper #3

Pros:

Matched every ADHD case with a control with matching demographics

Cons:

Questionable if experiment can be run without error at every lab

Cons:

Unnecessary page-long description of statistics

Cons:

No plan for MRI scans w/ movement; All participants on medication; 1 female

Results

Paper #1

Pros:

Focused on the effects of secondary variables on specific structures

Paper #2

Pros:

Included data linking behavior ratings with brain structures

Paper #3

Pros:

Data presentation answers objectives and hypothesis

Cons:

2 graphs for 4 data tables

Cons:

1 graph for 3 data tables

Cons:

Used color to distinguish data in a graph

discussion

Paper #1

Pros:

Advocates for DSM update to lower stigma

Paper #2

Pros:

Openly discussed limitations of study

Paper #3

Pros:

Proposed future experiments

Cons:

Discussed limitations, but heavily overshadowed by positives

Cons:

Repeats results

Cons:

Discussed only having a medication group but overlooked past research on subject

Overview

Paper #1

Pros:

Added Research in context section

Paper #2

Pros:

Data tables easy to read and interpret

Paper #3

Pros:

Free space for eyes to rest

Cons:

Graphs at end of paper

Cons:

Results section of abstract absurdly long

Cons:

Smallest number of brain scans

Conclusion

My favorite: Paper #1; Hoogman et al. 2017

My least favorite: Paper #3; Batty et al. 2010

Each article added to this body of research in their own distinct way

Interesting Note: Papers 1 & 3 referenced paper 2

Any questions?