Abnormal amplitude of low-frequency fluctuations associated with rapid-eye movement in chronic primary insomnia patients

Abstract

PurposeChronic primary insomnia (CPI) is the most prevalent sleep disorder worldwide. CPI manifests as difficulties in sleep onset, maintaining sleep, prolonged sleep latency, and daytime impairment and is often accompanied by cognitive problems such as poor academic performance, poor attention, and decreased memory. The most popular explanation of insomnia is hyperarousal or increased activities of neurons. Rapid eye movement (REM) sleep detected by polysomnography (PSG) exhibits a positive relationship with brain homeostasis and can be helpful for optimally preparing an organism for emotional and social function. Limited work has been performed to explore brain function of insomnia patients in combination with PSG analysis.ResultsWe observed increased ALFF within areas related to hyperarousal such as the midbrain and bilateral extra-nucleus, whereas decreased ALFF was observed within areas associated with memory and attention involving the parietal and occipital lobule and others. Furthermore, the altered ALFF was associated with the duration of insomnia, sleep efficiency, duration of REM, latency of RME and ratio of REM.Materials and MethodsIn this study, we recruited twenty-five CPI patients and twenty-five normal sleep (NS) volunteers as a control group to investigate the amplitude of low-frequency fluctuations (ALFF) and the correlation between those altered ALFF regions through resting-state fMRI and PSG data.ConclusionsThese findings suggest that hyperarousal reflected by ALFF abnormality within brain areas related to cognition and emotion in insomnia associated with REM sleep.

A lack of consistent brain alterations in insomnia disorder: An activation likelihood estimation meta-analysis

“…Moreover, applied rs-fMRI methods in ID were also diverse e.g. independent component analysis (ICA), amplitude of low-frequency fluctuations (ALFF), regional homogeneity, and whole brain functional connectivity (40)(41)(42)(43)(44)(45)(46)(47). Similarly, although there is no experimental variability in the included structural MRI (27,30,31) and PET studies (32,33), analytical heterogeneity such as various statistical thresholds or spatial transformation of the brain images is an important issue in such studies.…”

“…Our screening process yielded 19 studies consisting of 6 task-based fMRI, 8 rs-fMRI, 3 VBM, and 2 PET publications comprising 404 patients with ID and 395 good sleepers (27,(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47) (Table 1, S1). Recorded data includes the first author's name, year of publication, age, gender, number of subjects, scanning modality, and the peak coordinates (x,y,z) in Talairach (57) or Montreal neurological institute (MNI) (58) stereotactic space.…”

Altered Spontaneous Brain Activity in Patients With Idiopathic Trigeminal Neuralgia

“… 30 This index was subsequently used to differentiate 2 resting states, that is, eyes open versus eyes closed. 31 Moreover, ALFF has already been applied to patient studies including chronic pain, 32 , 33 attention deficit hyperactivity disorder, 34 and early Alzheimer disease. 35 However, it has been indicated that the ALFF is also sensitive to the physiological noise.…”

The functional and structural characteristics of the emotion network in alexithymia

“… 22 , 23 The images were corrected for slice-time differences, realigned for head motion correction, co-registered to T1, and spatially smoothed, according to a previous study’s suggestion. 24 The amplitude of low-frequency fluctuation (ALFF) map was calculated and the ALFF values of 21 regions of interest (ROI) in the emotion network were extracted. The ROI selection was based on the previous studies ( Table 1 ).…”