Neurocognitive Functions and Brain Volume in Patients with Endogenous Cushing's Syndrome Before and After Curative Surgery

Cognitive decline in Cushing's syndrome: A systematic review

The neurocognitive and psychiatric effects of Cushing's syndrome (CS) are well recognized and negatively impact quality of life. The aim of this systematic review is to compare neurocognitive disease, psychiatric symptoms, and structural brain changes in patients with Cushing's disease (CD)/CS and those with non-functioning pituitary adenoma (NFPA), both before and after surgical treatment, and in comparison to healthy controls. Possible predictors of persistent neurocognitive symptoms and reduced quality of life in patients with CS are highlighted. We reviewed the English literature published in Medline/Pubmed until 2021 to identify eligible studies. This systematic review was registered on Prospero and reported following the PRISMA statement guidelines. The initial literature search yielded 1772 articles, of which 1096 articles remained after removing duplicates. After excluding case reports, animal studies, narrative reviews, comparative reviews, and articles not in English, 86 papers underwent full-text review. Studies eligible for inclusion met the following criteria: (1) described patients with CD/CS, (2) reports of psychiatric symptoms, (3) written in English or with available English translation, and (4) published in a peer-reviewed journal. The full-text review process identified 40 eligible studies. The 40 studies included a total of 2603 participants with CD or CS, with 45.2% of the total participants having CD. The majority of studies were case-control studies and used validated questionnaires such as the Beck's Depression Index, Trail Making Test, Hospital Anxiety and Depression Scale, and Cushing Quality of Life for screening. Compared to NFPA controls, patients with CD who had greater baseline serum cortisol levels had worse cognitive function, even after surgical remission. This suggests a possible association between greater baseline cortisol levels in patients with CS and persistent cognitive impairment. A longer duration of uncontrolled CS was associated with worse cognitive function; however, there was no association found between the length of remission and memory. Overall brain volume was increased in patients in remission from CD compared to active disease. However, temporal and frontal lobe volumes did not recover to normal volumes. Patients with CS experience neurocognitive dysfunction, psychiatric disorders, and diminished quality of life, and symptoms may persist after curative surgery. We found several factors consistently associated with persistent cognitive and neuropsychiatric symptoms in patients with CS including higher pre-operatively baseline cortisol production, longer duration of disease, frontal and temporal lobe atrophy, and the presence of cognitive and neuropsychiatric symptoms at baseline. Larger prospective studies are required to validate these findings.

Reversibility of Impaired Large-Scale Functional Brain Networks in Cushing's Disease after Surgery Treatment: A Longitudinal Study

INTRODUCTION

Chronic exposure to excessive endogenous cortisol leads to brain changes in Cushing's disease (CD). However, it remains unclear how CD affects large-scale functional networks (FNs) and whether these effects are reversible after treatment. This study aimed to investigate functional network changes of CD patients and their reversibility in a longitudinal cohort.

METHODS

Active CD patients (N = 37) were treated by transsphenoidal pituitary surgery and reexamined 3 months later. FNs were computed from resting-state fMRI data of the CD patients and matched normal controls (NCs, N = 37). A pattern classifier was built on the FNs to distinguish active CD patients from controls and applied to FNs of the CD patients at the 3-month follow-up. Two subgroups of endocrine-remitted CD patients were identified according to their classification scores, referred to as image-based phenotypically (IBP) recovered and unrecovered CD patients, respectively. The informative FNs identified by the classification model were compared between NCs, active CD patients, and endocrine-remitted patients as well as between IBP recovered and unrecovered CD patients to explore their functional network reversibility.

RESULTS

All 37 CD patients reached endocrine remission after treatment. The classification model identified three informative FNs, including cerebellar network (CerebN), fronto-parietal network (FPN), and default mode network. Among them, CerebN and FPN partially recovered toward normal at 3 months after treatment. Moreover, the informative FNs were correlated with 24-h urinary-free cortisol and emotion scales in CD patients.

CONCLUSION

These findings suggest that CD patients have aberrant FNs that are partially reversible toward normal after treatment.

Persisting neuropsychiatric symptoms, Alzheimer's disease, and cerebrospinal fluid cortisol and dehydroepiandrosterone sulfate

INTRODUCTION

Neuropsychiatric symptoms are important treatment targets in the management of dementia and can be present at very early clinical stages of neurodegenerative diseases. Increased cortisol has been reported in Alzheimer's disease (AD) and has been associated with faster cognitive decline. Elevated cortisol output has been observed in relation to perceived stress, depression, and anxiety. Dehydroepiandrosterone sulfate (DHEAS) has known anti-glucocorticoid effects and may counter the effects of cortisol.

OBJECTIVES

We aimed to examine whether CSF cortisol and DHEAS levels were associated with (1) neuropsychiatric symptoms at baseline, (2) changes in neuropsychiatric symptoms over 3 years, and (3) whether these associations were related to or independent of AD pathology.

METHODS

One hundred and eighteen participants on a prospective study in a memory clinic setting, including patients with cognitive impairment (n = 78), i.e., mild cognitive impairment or mild dementia, and volunteers with normal cognition (n = 40), were included. Neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory Questionnaire (NPI-Q). CSF cortisol and DHEAS, as well as CSF AD biomarkers, were obtained at baseline. Neuropsychiatric symptoms were re-assessed at follow-up visits 18 and 36 months from baseline. We constructed linear regression models to examine the links between baseline neuropsychiatric symptoms, the presence of AD pathology as indicated by CSF biomarkers, and CSF cortisol and DHEAS. We used repeated-measures mixed ANCOVA models to examine the associations between the neuropsychiatric symptoms' changes over time, baseline CSF cortisol and DHEAS, and AD pathology.

RESULTS

Higher CSF cortisol was associated with higher NPI-Q severity scores at baseline after controlling for covariates including AD pathology status (B = 0.085 [0.027; 0.144], p = 0.027; r = 0.277). In particular, higher CSF cortisol was associated with higher baseline scores of depression/dysphoria, anxiety, and apathy/indifference. Elevated CSF cortisol was also associated with more marked increase in NPI-Q scores over time regardless of AD status (p = 0.036, η² = 0.207), but this association was no longer significant after controlling for BMI and the use of psychotropic medications. CSF DHEAS was associated neither with NPI-Q scores at baseline nor with their change over time. Cortisol did not mediate the association between baseline NPI-Q and changes in clinical dementia rating sum of boxes over 36 months.

CONCLUSION

Higher CSF cortisol may reflect or contribute to more severe neuropsychiatric symptoms at baseline, as well as more pronounced worsening over 3 years, independently of the presence of AD pathology. Our findings also suggest that interventions targeting the HPA axis may be helpful to treat neuropsychiatric symptoms in patients with dementia.