Cerebral Asymmetry in Insomnia Sufferers

Abstract

Cerebral asymmetry is used to describe the differences in electroencephalographic activity between regions of the brain. The objective of this study was to document frontal, central, and parietal asymmetry in psychophysiological (Psy-I) and paradoxical (Para-I) insomnia sufferers as well as good sleeper (GS) controls, and to compare their patterns of asymmetry to others already found in anxiety and depression. Additionally, asymmetry variations between nights were assessed. Participants were 17 Psy-I, 14 Para-I, and 19 GS (mean age = 40 years, SD = 9.4). They completed three nights of polysomnography (PSG) recordings following a clinical evaluation in a sleep laboratory. All sleep cycles of Nights 2 and 3 were retained for power spectral analysis. The absolute activity in frequency bands (0.00–125.00 Hz) was computed at multiple frontal, central, and parietal sites in rapid eye movement and non-rapid eye movement sleep to provide cerebral asymmetry measures. Mixed model ANOVAs were computed to assess differences between groups and nights. Correlations were performed with asymmetry and symptoms of depression and anxiety from self-reported questionnaires. Over the course of the two nights, Para-I tended to present hypoactivation of their left frontal region but hyperactivation of their right one compared with GS. As for Psy-I, they presented increased activation of their right parietal region compared with Para-I. Asymmetry at frontal, central, and parietal region differed between nights. On a more disrupted night of sleep, Psy-I had increased activity in their right parietal region while Para-I presented a decrease in cerebral activity in the right central region on their less disrupted night of sleep. Anxious and depressive symptoms did not correlate with asymmetry at any region. Therefore, Psy-I and Para-I present unique patterns of cerebral asymmetry that do not relate to depression or anxiety, and asymmetry varies between nights, maybe as a consequence of variability in objective sleep quality from night to night.

Cortical Structural Connectivity Alterations in Primary Insomnia: Insights from MRI-Based Morphometric Correlation Analysis

“…Although, by far, there is no clear evidence about asymmetric effects of insomnia on the brain, previous studies have also reported lateralized patterns of brain structural alterations in PI [ 67 – 69 ]. It is plausible that the asymmetric structural changes may be related to the abnormal functional asymmetries in patients with PI during night or sleep [ 70 , 71 ]. In addition, we also noted that only the SCNs of the primary auditory and olfactory regions showed statistically significant alterations in patients with PI (survived in the multiple comparison correction), but the SCNs of the primary visual cortex.…”

HIRREM™: a noninvasive, allostatic methodology for relaxation and auto‐calibration of neural oscillations

“…Frontal EEG asymmetry has been described as a marker for affective style, with left and right frontal cortex associated with approach and withdrawal tendencies, respectively (Davidson et al 1990). Other reports have associated hemispheric oscillatory asymmetry with posttraumatic stress disorder (Rabe et al 2006;Engdahl et al 2010), insomnia (St-Jean et al, 2012), attention-deficit disorder (Hale et al 2010), autism (Stroganova et al 2007;Lazarev et al 2010), dyslexia (Spironelli et al 2008), and schizophrenia (Swanson et al 2010). Whether there could be a physiologic disturbance common to these asymmetries has not been much considered, but the hemispheric lateralization of management of the autonomic nervous system functioning (Yoon et al 1997;Avnon et al 2004;Craig 2005)sympathetic and parasympathetic divisions by the right and left hemispheres, respectivelyseems to raise the possibility that hemispheric oscillatory asymmetry may be an indicator of dysregulation of autonomic nervous system functioning.…”

“…; Engdahl et al. ), insomnia (St‐Jean et al., ), attention‐deficit disorder (Hale et al. ), autism (Stroganova et al.…”

REM sleep as a potential indicator of hyperarousal in psychophysiological and paradoxical insomnia sufferers

“…Perhaps, finer REM sleep microstructure variables such as the density of the activities in the different frequency bands measured using PSA might be a better reflection of this heightened arousal in insomnia. Limited literature exists on this subject, but so far, results obtained using PSA tend to show significant differences between PSY-I, PARA-I and GS in the density of each frequency bands during REM sleep (Freedman, 1986;Krystal et al, 2002;Merica et al, 1998;Perlis et al, 2001;St-Jean et al, 2012. Therefore, it seems that this finer aspect of REM sleep microstructure is somehow related to the hyperarousal typically suggested in INS.…”