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