Locus coeruleus signal intensity and emotion regulation in agitation in Alzheimer's disease

Kathy Y Liu*, Matthew J Betts, Dorothea Hämmerer, Emrah Düzel, Mara Mather, Jonathan P Roiser, Anja Schneider, Annika Spottke, Ayda Rostamzadeh, Björn H Schott, Boris-Stephan Rauchmann, Christoph Laske, Daniel Janowitz, Eike J Spruth, Ersin Ersözlü, Falk Lüsebrink, Frank Jessen, Ingo Frommann, Ingo Kilimann, Jens WiltfangJohanna Brustkern, Josef Priller, Julian Hellman-Regen, Katharina Buerger, Klaus Fliessbach, Klaus Scheffler, Luca Kleineidam, Melina Stark, Michael Ewers, Michael Wagner, Oliver Peters, Peter Dechent, Robert Perneczky, Sebastian Sodenkamp, Stefan Hetzer, Stefan Teipel, Wenzel Glanz, Robert Howard

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Hyperphosphorylated tau accumulation is seen in the noradrenergic locus coeruleus from the earliest stages of Alzheimer's disease onwards and has been associated with symptoms of agitation. It is hypothesized that compensatory locus coeruleus-noradrenaline system overactivity and impaired emotion regulation could underlie agitation propensity, but to our knowledge this has not previously been investigated. A better understanding of the neurobiological underpinnings of agitation would help the development of targeted prevention and treatment strategies. Using a sample of individuals with amnestic mild cognitive impairment and probable mild Alzheimer's disease dementia from the German Center for Neurodegenerative Diseases (DZNE)-Longitudinal Cognitive Impairment and Dementia (DELCODE) study cohort ( N = 309, aged 67-96 years, 51% female), we assessed cross-sectional relationships between a latent factor representing the functional integrity of an affect-related executive regulation network and agitation point prevalence and severity scores. In a subsample of individuals with locus coeruleus MRI imaging data ( N = 37, aged 68-93 years, 49% female), we also investigated preliminary associations between locus coeruleus MRI contrast ratios (a measure of structural integrity, whole or divided into rostral, middle, and caudal thirds) and individual affect-related regulation network factor scores and agitation measures. Regression models controlled for effects of age and clinical disease severity and, for models including resting-state functional MRI connectivity variables, grey matter volume and education years. Agitation point prevalence showed a positive relationship with a latent factor representing the functional integrity (and a negative relationship with a corresponding structural measure) of the affect-related executive regulation network. Locus coeruleus MRI contrast ratios were positively associated with agitation severity (but only for the rostral third, in N = 13) and negatively associated with the functional affect-related executive regulation latent factor scores. Resting-state functional connectivity between a medial prefrontal cortex region and the left amygdala was related to locus coeruleus MRI contrast ratios. These findings implicate the involvement of locus coeruleus integrity and emotion dysregulation in agitation in Alzheimer's disease and support the presence of potential compensatory processes. At the neural level, there may be a dissociation between mechanisms underlying agitation risk per se and symptom severity. Further studies are needed to replicate and extend these findings, incorporating longitudinal designs, measures of autonomic function and non-linear modelling approaches to explore potential causal and context-dependent relationships across Alzheimer's disease stages.

Original languageEnglish
Pages (from-to)fcae457
JournalBrain Communications
Volume7
Issue number1
Early online date17 Dec 2024
DOIs
Publication statusE-pub ahead of print - 17 Dec 2024

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