Disrupted Regional Spontaneous Neural Activity in Mild Cognitive Impairment Patients with Depressive Symptoms: A Resting-State fMRI Study

Abstract

Depressive symptoms are common in individuals with mild cognitive impairment (MCI) who have an increased risk of dementia. It is currently unclear whether the pattern of spontaneous brain activity in patients with MCI differs between subjects with and without depressive symptoms. The current study sought to investigate the features of spontaneous brain activity in MCI patients with depressive symptoms (D-MCI) using coherence regional homogeneity (CReHo) analysis with resting-state functional magnetic resonance imaging (rsfMRI). We obtained rsfMRI data in 16 MCI patients with depressive symptoms and 18 nondepressed MCI patients (nD-MCI) using a 3 T scanner. Statistical analyses were performed to determine the regions in which ReHo differed between the two groups in specific frequency bands, slow-4 (0.027–0.073 Hz) and slow-5 (0.010–0.027 Hz), and typical bands (0.01–0.08 Hz). Correlation analyses were performed between the CReHo index of these regions and clinical variables to evaluate the relationship between CReHo and pathophysiological measures in the two groups. Our results showed that D-MCI patients exhibited significantly higher CReHo in the left Heschl's gyrus and left thalamus and lower CReHo in the left postcentral gyrus in the typical frequency band. In the slow-4 frequency band, D-MCI patients showed significantly higher CReHo in the left Heschl's gyrus and left thalamus. In the slow-5 frequency band, D-MCI patients exhibited significantly lower CReHo in the superior medial prefrontal gyrus. In addition, the results revealed that CReHo values in the left thalamus were positively correlated with Hamilton Depression Rating Scale (HAMD) scores in D-MCI patients. These results suggest that the sensorimotor network may be one of the main pathophysiological factors in D-MCI.

Depression Affects Intrinsic Brain Activity in Patients With Mild Cognitive Impairment

“…Although it is still unclear what causes the difference between those parameters and the potential physiological significance might be, with the limitation of each parameters, it is still necessary to take into consideration all these metrics (Zuo et al, 2010). We found ReHo only decreased in cerebellum, while another study found that MCID patients showed significantly higher coherence ReHo (cReHo) than MCIND patients in the left Heschl's gyrus and thalamus, lower cReHo in the left postcentral gyrus (Liu et al, 2019). These differences may be influenced by different calculation of ReHo.…”

“…IBA involves dynamic neural and metabolic activities, it is activity and plays a pivotal role in brain function (Dai and He, 2014;Raichle, 2015). These methods have been widely used to evaluate the IBA of neurological disorders or neuropsychiatric disorders, such as AD, depression, and MCI (Yao et al, 2009;Zhang et al, 2012;Guo et al, 2016;Wee et al, 2016;Stoyanov et al, 2017;Zhang et al, 2017;Kandilarova et al, 2018;Yang et al, 2018;Liu et al, 2019). Furthermore, evidence indicated that once brain got an internal or external stimuli, it could respond by dynamic integration or adjustment over multiple time scales (Hutchison et al, 2013;Bassett and Sporns, 2017;Yan et al, 2017).…”

“…Studies have identified regions in MCI compared with the NC, with a decreased or increased ALFF/fALFF/ReHo (Han et al, 2011;Zhang et al, 2012;Dai and He, 2014;Liu et al, 2018Liu et al, , 2019Yang et al, 2018). Previous study found that changes from ALFF/fALFF measurements of IBA may be worthwhile to characterize the early and gradual changes in physiological alterations throughout AD progression (Yang et al, 2018).…”

“…Another study found that abnormal ALFF values in MCID group could serve as markers to effectively differentiate MCID from MCI patients . As for ReHo, it can be used to classify the depression subtypes and MCI, also changes in ReHo could be a biomarker for the pathophysiology and therapeutic response of depression (Guo et al, 2013;Liu et al, 2019). Previously, by combining dynamic FC with static FC, some studies found that the diagnostic accuracy for MCI could be significantly improved (Wee et al, 2016;Zhang et al, 2017).…”

Information Delivery Methods and their Association with Older Adults Memory and Comprehension

“…Surprisingly, when we examined comprehension results per groups, the results were multifaceted. For example, in groups A and C, the "figures and words" instructions resulted in the highest scores; whereas, "figures only" instructions resulted in the highest score in group B [26][27][28]. Furthermore, the scores of those receiving "words only" instructions in group C was very low.…”