Brain Imaging in Diagnosis of Lewy Body Dementia

Brain image highlighting right insula implicated in DLB

Recent information has emerged concerning the suicide death of the comedian/actor Robin Williams.

Autopsy results have demonstrated that Robin Williams suffered from dementia with Lewy bodies (DLB).

This public case demonstrates the difficulty in making a correct diagnosis of DLB prior to the findings at autopsy.

In a previous post I reported on a screening tool for clinicians that appears to have some promise for screening for high-risk DLB patients.

In this post, I want to follow up on this topic by reviewing a recent brain imaging study that targeted patterns of brain cortical thinning in the dementias.

The key elements in the design of this research study included the following elements:

• Subjects: 28 subjects with prodromal DLB, 27 subjects with prodromal Alzheimer's disease (AD), 31 subjects with DLB, 54 subjects with AD and cognitively normal elderly adults.
• Brain Imaging: Structural magnetic resonance imaging (MRI) with a 3 Tesla scanner
• Statistical Analysis: FreeSurfer analysis of regional cortical thickness pattern across diagnosis groups

The key findings from the study included the following:

• DLB subjects showed distinct patterns of cortical thinning compared to AD
• DLB was associated with increased thinning of the right insular cortex
• AD was associated with left parahippocampal thinning and bilateral parietal lobe thinning
• In those with full dementia, AD subjects demonstrated more thinning in the enterorhinal cortex

The authors of this study note in the discussion section of the paper that the key finding is the finding of right insular cortex thinning in DLB. This finding may allow use of brain imaging as a sensitive addition to the use of clinical and neuropsychological assessment in elderly with early and later dementia.

This study will need to be replicated in additional independent samples. Some research groups may already have scan data that may be able to be analyzed in an attempt to replicate the current study.

Readers with more interest in the study can access the free full-text manuscript by clicking on the PMID link in the citation below.

Image of the right insular cortex is from a screen shot from my iPad using the Brain Tutor app.

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Blanc F, Colloby SJ, Philippi N, de Pétigny X, Jung B, Demuynck C, Phillipps C, Anthony P, Thomas A, Bing F, Lamy J, Martin-Hunyadi C, O'Brien JT, Cretin B, McKeith I, Armspach JP, & Taylor JP (2015). Cortical Thickness in Dementia with Lewy Bodies and Alzheimer's Disease: A Comparison of Prodromal and Dementia Stages. PloS one, 10 (6) PMID: 26061655

The Brain Insula: Function and Disease

Nature Reviews Neuroscience is a scientific journal dedicated to neuroscience topics that recently celebrated it’s ten year anniversary.  To commemorate the accomplishment, the most highly cited articles from each of the last 10 years was identified.  This method provides a good proxy for the most important publication each year.  The 2009 most cited article was Dr. A.D. Craig’s article entitled: “How do you feel—now? The anterior insula and human awareness”.

Dr. Craig’s article highlights the converging fields of knowledge about the brain cortex region known as the insula.  This region lays hidden inside the brain in close proximity to the anterior cingulate gyrus (ACC).  The ACC is receiving increased attention as an important area for emotional processing.   The insula and the ACC have significant numbers of connections supporting a role for their mutual role in a variety of brain functions. 

The insula has been long identified as a sensory region for the gut and body.  New anatomical and imaging research has identified significant expanded domains related to the insular cortex including:

• Interoception (sensing state of gut, heart, pain etc)
• Body movement
• Self-recognition
• Vocalizationand music
• Emotional awareness
• Risk, uncertainty and anticipation
• Visual and auditory awareness of movement
• Time perception
• Attention
• Perceptual decision-making
• Cognitive control and performance monitoring

Dr. Craig provides a summary of the research supporting the expanded role of the insula in each of  these additional domains.  He notes that the expanding role of the insula is supportive of the James-Lang theory of emotion.  The James-Lang theory of emotion denotes a theory developed independently by William James and Carl Lange in the 19^th century.  Their theory states that emotions follow rather than precede the autonomic nervous system changes to environmental stimuli.  So instead of the sequence 1.) see bear, 2.) experience fear, 3.) heart races, the James-Lang theory states the correct sequence is 1.) see bear, 2.) heart races, 3.) experience fear.   The James-Lang theory. 

The evolving research on insular cortex function also supports the somatic marker hypothesis of Antonio Damasio from the University of Iowa.  Damasio proposes that decision making is influenced by somatic/emotional processes that can guide or bias our behaviors.  These somatic/emotional processes are thought to be stored in the ventromedial prefrontal cortex regions.

There are going to be significant discoveries related to a variety of clinical neuroscience disorders that are likely to involve the insular cortex.  There is already evidence of it playing a key role in such diverse disorders as:

• Autism
• ADHD
• Addictions including nicotine dependence
• Anorexia nervosa
• Major depression
• Pain disorders
• Alzheimer’s disease (in nonfluent primary progressive aphasia)

 I highly recommend both the 10 year anniversary manuscript as well as the 2009 summary of research on the insula.  They are both packed with data and commentary that I found quite revealing and intriquing.

Photo of iPad snap shot of Brain Tutor app with insular cortex in blue courtesy of Yates Photography.

Craig AD (2009). How do you feel--now? The anterior insula and human awareness. Nature reviews. Neuroscience, 10 (1), 59-70 PMID: 19096369


Luo L, Rodriguez E, Jerbi K, Lachaux JP, Martinerie J, Corbetta M, Shulman GL, Piomelli D, Turrigiano GG, Nelson SB, Joëls M, de Kloet ER, Holsboer F, Amodio DM, Frith CD, Block ML, Zecca L, Hong JS, Dantzer R, Kelley KW, & Bud Craig AD (2010). Ten years of Nature Reviews Neuroscience: insights from the highly cited. Nature reviews. Neuroscience, 11 (10), 718-26 PMID: 20852655