Higher cardiovascular activation, but normal heartbeat-evoked potentials and cardiac interoceptive accuracy in somatoform disorders and major depressive disorder

in Psychiatry Research Communications (2022), 2(3), 100052

The perception-filter model posits that the generation of medically-unexplained symptoms is associated with (I.) more intense afferent bodily signals, (II.) impaired filter system activity to ... [more ▼]

The perception-filter model posits that the generation of medically-unexplained symptoms is associated with (I.) more intense afferent bodily signals, (II.) impaired filter system activity to differentiate relevant from irrelevant signals, and (III.) altered perception of bodily signals. We tested these assumptions for cardiac perception in patients with somatoform disorders (SFD), patients with major depressive disorder (MDD) and healthy control (HC) individuals. Heart rate (variability; HR/HRV) and blood pressure served as indicators of bodily signals (I.); heartbeat-evoked potentials (HEPs) assessed during a heartbeat counting task (HCT) and a distraction task indicated filter system activity (II.); interoceptive accuracy (IAc) in the HCT was interpreted as an index of perception (III.). All indicators were assessed before and after a socially-evaluated cold pressor stress task (SECPT) and a control intervention. SFD patients (n ​= ​24) showed higher average HR and diastolic blood pressure, as well as lower HRV than HC individuals (n ​= ​22), but there were no differences in HEPs or IAc. Neither were there significant differences between the SFD and the MDD groups (n ​= ​24), nor any stress effect on HEPs or IAc. Our findings suggest that increased intensity of bodily signals (I.) is the only model assumption that could be supported for patients with fully-developed SFD. [less ▲]

Impaired filter function in patients with somatoform disorders and major depression, as reflected by auditory evoked potentials in an oddball and an active distraction paradigm

in Abstractband Psychologie und Gehirn 2018 (2018)

Introduction: In the in influential perception-filter model of somatoform disorders (SD), three stages of symptom perception are postulated: (1) bodily signals, which may be amplified by stress, (2) a ... [more ▼]

Introduction: In the in influential perception-filter model of somatoform disorders (SD), three stages of symptom perception are postulated: (1) bodily signals, which may be amplified by stress, (2) a filter system, which distinguishes between relevant and irrelevant stimuli, and (3) cortical perception of physical symptoms. As there is dearth of evidence so far supporting the relationship between (1) bodily signals and (2) filter processes in SD, this study investigated if filter processes are altered in SD and if stress may affect filter mechanisms. Methods: Twenty-four patients with SD, 24 with depression and 24 healthy control individuals were assessed. Event-related potentials (ERPs) with two different auditory distraction procedures were recorded over four blocks, one before and three after either a socially evaluated cold pressor test (SECPT) or a control procedure. We manipulated both the frequency of and the attentional focus on stimuli to reflect filter processes. Results: We found smaller P3b amplitudes (reflecting memory storage) in patients with depression and SD, as compared to healthy controls. Furthermore, both patient groups showed a smaller P3a amplitude (reflecting attention), when counting the infrequent tone ("Oddball task") and a smaller N1 amplitude when counting the frequent tone ("active distraction"). In patients with SD, the SECPT had a decreasing effect on P3a amplitudes. Conclusions: Both late filter processes, reflecting attention (P3a) and memory storage (P3b), may be impaired in SD and depression. As acute stress affected attention in SD patients only, the impact of bodily signals (1) on filter processes (2) may be specific for SD. [less ▲]