Neural Correlates of Anosognosia in Neurocognitive Disorders
Poster No:
55
Submission Type:
Abstract Submission
Authors:
Serap Özlü1
Institutions:
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
First Author:
Introduction:
Dementia, also known as major neurocognitive disorder, is a comprehensive term used to describe the loss of cognitive abilities, changes in memory, language functions and alterations in behavior.(1) Major neurocognitive disorders have significant repercussions on patients, their families, the economy, and healthcare systems. (2) Anosognosia is a word of Ancient Greek origin that translates to "without knowledge of disease".
Anosognosia represents a multifaceted neurological phenomenon that exists along a spectrum. It pertains to situations, where individuals are unable to recognize or accurately assess the deficits caused by their disease. Anosognosia has substantial implications for individuals with dementia and the caregivers who support them. (3)
The primary objective of this study was to explore the neural underpinnings of anosognosia in individuals with neurodegenerative diseases. Given the complexity of anosognosia research, our approach was characterized by an unbiased, systematic investigation, and a meta-analysis conducted without any predefined hypotheses.
Anosognosia represents a multifaceted neurological phenomenon that exists along a spectrum. It pertains to situations, where individuals are unable to recognize or accurately assess the deficits caused by their disease. Anosognosia has substantial implications for individuals with dementia and the caregivers who support them. (3)
The primary objective of this study was to explore the neural underpinnings of anosognosia in individuals with neurodegenerative diseases. Given the complexity of anosognosia research, our approach was characterized by an unbiased, systematic investigation, and a meta-analysis conducted without any predefined hypotheses.
Methods:
The systematic review was conducted in accordance with PRISMA guidelines. The protocol for the systematic review and meta-analysis was registered on the database PROSPERO. The comprehensive search is conducted by using the electronic database MEDLINE (PubMed). Anosognosia-related keywords were included following an extensive literature search, while the classification of neurodegenerative diseases was based on the DSM-5 criteria. The search strategy consists of three main categories: neurodegenerative diseases, lack of awareness and neuroimaging methods. Two independent reviewers conducted a thorough screening of article titles and abstracts, and where necessary, they examined full texts in accordance with a predefined search strategy. Studies failing to meet the eligibility criteria were systematically excluded from the analysis. Data are extracted from papers according to a predesigned data collection form.
For meta-analysis Brainmap GingerALE (v3.0.2) software is used. GingerALE is designed for conducting meta-analyses of neuroimaging studies via the activation likelihood estimation (ALE) method. (4) For the quality assessment of studies, we used the Newcastle-Ottawa Scale adapted version of cross-sectional studies. Lastly, we conducted Jackknife sensitivity analysis to test the reliability of the results.
For meta-analysis Brainmap GingerALE (v3.0.2) software is used. GingerALE is designed for conducting meta-analyses of neuroimaging studies via the activation likelihood estimation (ALE) method. (4) For the quality assessment of studies, we used the Newcastle-Ottawa Scale adapted version of cross-sectional studies. Lastly, we conducted Jackknife sensitivity analysis to test the reliability of the results.
Results:
During the initial screening phase, we identified a total of 1,904 studies. Following eligibility criteria, we arrived at a final selection of 16 studies that met the criteria for inclusion in the systematic review. All studies used appropriate measurements, and diagnostic criteria, and included representative
groups of relative dementia subtypes.
In the ALE analysis, the results revealed two clusters and three peak coordinates. Gray matter correlations of dementia across all groups showed that medial frontal gyrus and cingulate gyrus were mainly affected areas by anosognosia.
The outcomes of the jackknife sensitivity analysis revealed the stability of specific brain regions. The medial frontal gyrus demonstrated robust stability in 12 out of 16 iterations, while the cingulate gyrus exhibited stability in 14 out of 16 iterations.
groups of relative dementia subtypes.
In the ALE analysis, the results revealed two clusters and three peak coordinates. Gray matter correlations of dementia across all groups showed that medial frontal gyrus and cingulate gyrus were mainly affected areas by anosognosia.
The outcomes of the jackknife sensitivity analysis revealed the stability of specific brain regions. The medial frontal gyrus demonstrated robust stability in 12 out of 16 iterations, while the cingulate gyrus exhibited stability in 14 out of 16 iterations.
Conclusions:
Awareness of a disease has significant impacts on both patient and caregiver in terms of having the correct diagnosis and following an appropriate treatment. Patients with anosognosia struggle with self-evaluation of disease-related symptoms and decline. Therefore, it is necessary to understand the underlying mechanisms of this phenomenon and its correlates in the brain. To our knowledge this is the first coordinate based meta-analysis on anosognosia in several types of dementia. Our results,aligning with previous research findings (5) (6), revealed that reduced gray matter volumes and diminished metabolic activity within the medial frontal gyrus and cingulate gyrus are inversely correlated with the severity of anosognosia.
Brain Stimulation:
Non-invasive Magnetic/TMS 1
Disorders of the Nervous System:
Neurodegenerative/ Late Life (eg. Parkinson’s, Alzheimer’s) 2
Higher Cognitive Functions:
Higher Cognitive Functions Other
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Cortical Anatomy and Brain Mapping
Keywords:
Cognition
Consciousness
Degenerative Disease
FUNCTIONAL MRI
Meta- Analysis
Meta-Cognition
MRI
Positron Emission Tomography (PET)
1|2Indicates the priority used for review
Provide references using author date format
2: Hugo, J., & Ganguli, M. (2014). Dementia and cognitive impairment: epidemiology, diagnosis, and treatment. Clinics in geriatric medicine, 30(3), 421–442. https://doi.org/10.1016/j.cger.2014.04.001
3: Howard J. Rosen (2011) Anosognosia in neurodegenerative disease, Neurocase: The Neural Basis of Cognition, 17:3, 231-241
4: Eickhoff, S. B., Laird, A. R., Grefkes, C., Wang, L. E., Zilles, K., & Fox, P. T. (2009). Coordinate-based activation likelihood estimation meta-analysis of neuroimaging data: a random-effects approach based on empirical estimates of spatial uncertainty. Human brain mapping, 30(9), 2907–2926. https://doi.org/10.1002/hbm.20718
5: Jobson, D. D., Hase, Y., Clarkson, A. N., & Kalaria, R. N. (2021). The role of the medial prefrontal cortex in cognition, ageing and dementia. Brain communications, 3(3), fcab125. https://doi.org/10.1093/braincomms/fcab125
6: Tan, R. H., Pok, K., Wong, S., Brooks, D., Halliday, G. M., & Kril, J. J. (2013). The pathogenesis of cingulate atrophy in behavioral variant frontotemporal dementia and Alzheimer's disease. Acta neuropathologica communications, 1, 30. https://doi.org/10.1186/2051-5960-1-30