Cortical morphological alterations in cognitively normal Parkinson's disease with severe hyposmia

Early cortical alterations and neuropsychological mechanisms in amyotrophic lateral sclerosis

OBJECTIVE

This study investigates the characteristics of cortical structural and functional alterations in amyotrophic lateral sclerosis (ALS) patients and their modulation of emotional and cognitive functions, as well as to discuss their diagnostic value in early-stage ALS.

METHODS

Fifty-nine ALS patients (28 in ALS 1 and 31 in ALS 2, categorized using King's College Staging) and 31 healthy controls were evaluated using multiparametric MRI, motor and neuropsychological assessments, and serum neurofilament light chain (NfL) levels. Mediation analyses were performed to examine how cortical alterations influence the relationship between emotional and cognitive functions. Support vector machine (SVM) classification models were constructed to assess the diagnostic utility of differential cortical parameters.

RESULTS

ALS 1 patients exhibited increased cortical thickness (CT) and functional activity in the cingulate and frontotemporal regions, correlating with neuropsychological performance and NfL levels. Mediation analysis revealed that perigenual and frontotemporal functional activity significantly modulated the relationship between depressive symptoms and cognitive function. SVM classification showed that the combined altered regions with Amplitude of Low Frequency Fluctuations (ALFF) model achieved slightly better performance (AUC = 0.853, 95 %CI: 0.687-1.000, p < 0.001) compared to CT (AUC = 0.779, 95 %CI: 0.587-0.972, p < 0.001), although both models showed limited efficacy in differentiating between ALS 1 and ALS 2 groups.

CONCLUSIONS

Cortical structural and functional alterations in ALS mediate the impact of depression on cognitive function, offering insights into the neuropsychological mechanisms of the disease and potential biomarkers for early-stage diagnosis.

Cholinergic basal forebrain atrophy and cortical alterations in Parkinson's disease with apathy

INTRODUCTION

Emerging evidences support the contribution of cholinergic deficiency to apathy in Parkinson's disease (PD). We aimed to ascertain the role of structural alterations of cholinergic basal forebrain (BF) and its innervated cortical regions in the pathogenesis of apathy in PD.

METHODS

Twenty-one PD patients with apathy (PD-A), 28 without apathy (PD-NA), and 20 healthy controls (HCs) were recruited in this study. Changes in subregional volumes of the BF were compared. Cortical thickness and local gyrification index (LGI) analysis were adopted to reveal the concomitant cortical alterations. The correlation with the severity of apathy and the diagnostic capacity were also assessed.

RESULTS

Compared to PD-NA and HCs groups, PD-A group showed excessively nucleus basalis of Meynert (NBM/Ch4) atrophy (p < 0.05 after Bonferroni correction), accompanied by cortical thinning and hypergyrification of the right entorhinal cortex (p < 0.001 after Bonferroni correction). Furthermore, regression analysis showing that the Ch4 volume was negatively associated with the severity of apathy in PD-A group (β = -23.198, T = -1.063, p = 0.039). All the above significant neuroimaging alterations showed good performance in identifying apathetic patients (p < 0.001).

CONCLUSION

Our findings highlighted that BF cholinergic degeneration driven by Ch4 atrophy may be involved in the pathogenesis of apathy in PD patients without dementia or depression.

Sex-specific brain morphological and network differences in patients showing Parkinson's disease with and without possible rapid eye movement sleep behavior disorder

Background

Sex is a crucial determinant in the clinical manifestations of diseases. However, previous studies have not clarified whether altered brain morphology shows sex-specific patterns in patients with Parkinson's disease (PD) with or without possible rapid eye movement sleep behavior disorder (RBD). This study aimed to investigate sex-specific differences in the patterns of morphological changes among different subgroups of PD.

Methods

High-resolution T1-weighted magnetic resonance imaging and clinical scale data were collected from 278 participants in the Parkinson's disease Progression Marker Initiative database: 93 patients with PD-pRBD (60 males, 33 females), 114 patients showing PD without RBD (PDnon-pRBD group; 68 males, 46 females), and 71 healthy controls (HCs; 44 males, 17 females). The Computational Anatomy Toolbox (CAT) 12 was utilized to collect data on gray matter volume (GMV) and cortical morphological metrics. Subsequently, individual-level morphological similarity networks were constructed on the basis of these cortical metrics. Finally, the topological properties of the network were analyzed using graph theoretical methods.

Results

In the PD-pRBD group, the GMV in the frontal and temporal lobes of males was lower than that of females. In contrast, the gyrification index (GI) of the frontal lobe in males was lower than that in females within the PDnon-pRBD group. Network analyses based on graph theory revealed that male PD-pRBD patients showed lower network information integration than female patients, particularly in terms of the global properties of fractal dimension (FD) networks. Moreover, in the PD-pRBD group, male patients showed a strong correlation between morphological network metrics and cognitive performance, as measured by the Hopkins Verbal Learning Test-Revised (HVLT-R) memory scores.

Conclusion

The presence of more significant sex-related differences in brain morphological changes in the PD-pRBD group in comparison with the PDnon-pRBD group highlights the importance of considering sex-related differences in the diagnosis and management of patients with PD-pRBD.