Saliva amylase as a measure of sympathetic change elicited by autogenic training in patients with functional somatic syndromes

Salivary Alpha-Amylase as a Biomarker of Stress in Behavioral Medicine

In recent years, research in behavioral medicine has become increasingly focused on understanding how chronic and acute exposure to stress impacts health outcomes. During stress, the body’s physiological stress systems are activated. These systems closely interact with the immune system and are, thus, importantly implicated in the onset and maintenance of disease states. While much of the research in behavioral medicine that has investigated the effects of stress on disease has focused on the role of the hypothalamic-pituitary-adrenal axis and its downstream biomarker, cortisol, it is evident that the autonomic nervous system (ANS) also plays a crucial role in both the biological stress process and the manifestation and maintenance of stress-related symptoms. In recent years salivary alpha-amylase (sAA) has emerged as a valid and reliable marker of ANS activity in stress research and is therefore an important biomarker to consider in behavioral medicine. In this commentary, we will highlight research relevant for behavioral medicine that has utilized sAA measurements, both basally, and in response to stress, to examine ANS function in clinical populations. We will additionally summarize findings from studies that have examined the effects of various targeted interventions on changes in sAA levels. Through this, our aim is to present evidence that sAA can serve as a feasible biomarker of ANS (dys)function in health and disease. To this end, we will also highlight important methodological considerations for readers to keep in mind when including sAA assessments in their own studies. The overarching goal of this brief commentary is to highlight how a multidimensional approach toward physiological stress measurement can allow researchers to develop a better understanding of physical health and disease states.

The relationship between salivary amylase and the physical and psychological changes elicited by continuation of autogenic training in patients with functional somatic syndrome

Background

The aim of this study was to clarify the changes in biological measures during autogenic training (AT) sessions and the relationship between these biological measures and the changes in physical and psychological measures induced by continuation of AT in patients with functional somatic syndrome (FSS). We used the salivary amylase (SAMY) level, skin temperature of the finger (TEMP), subjective symptom scores, and psychological characteristics to assess these changes.

Methods

We assessed 24 patients with FSS and 23 healthy controls before and after AT. We then conducted the same tests after the participants had practiced AT at home 1 and 2 months later.

Results

The baseline SAMY levels in the first session were significantly higher in the FSS group than in the control group. However, this difference was not significant in the second and third sessions. The pattern of changes in TEMP induced by AT was not different between the FSS and control groups. Tension-anxiety and somatic symptoms in patients with FSS were improved by AT. In the FSS group, the baseline SAMY levels in the first session showed a significant negative correlation with the changes in the subjective symptom score and tension-anxiety score at baseline.

Conclusions

The practice of AT, both during the first session and after 1 month of continuation, eased the dysregulation of the autonomic nervous system that is reflected in SAMY in patients with FSS. AT also contributed to decreases in the tension-anxiety and somatic symptoms in patients with FSS. We suggest that SAMY is related to both physical and psychological effects of AT in patients with FSS.

Links among emotional awareness, somatic awareness and autonomic homeostatic processing

Emotional awareness and somatic interoceptive awareness are essential processes for human psychosomatic health. A typical trait of lacking emotional awareness related to psychosomatic symptoms is alexithymia. In contrast, alexisomia refers to the trait of lacking somatic awareness. Links between emotional and somatic awareness and homeostatic processing are also significant for the psychosomatic health. The purpose of the present paper is to review the links among emotional awareness, somatic interoceptive awareness and autonomic homeostatic processing. On the basis of the collected evidence, the following arguments were presented¹: (1) The main subcortical neural substrates for these processes are limbic-related systems, which are also responsible for autonomic functions for optimization of homeostatic efficiency. (2) Considerable studies have shown that autonomic activity and/or reactivity to stress correlate with both emotional and interoceptive awareness. A hypothesis was advocated about the links between the two types of awareness and autonomic function: Autonomic dysfunction, especially high sympathetic tone at baseline and/or attenuated reactivity or variability to stress, appears to be involved in disturbance of emotional and interoceptive awareness. (3) Several studies suggest that a link or a cooperative relationship exists between emotional and somatic awareness, and that somatic awareness is the more fundamental of the two types of awareness. Emotional awareness, somatic awareness and autonomic homeostatic processing generally occur in parallel or concurrently. However, some complex features of pathologies include coexistence of reduced interoceptive awareness and somatosensory amplification. The autonomic homeostatic process is fundamentally involved in emotional and somatic awareness. Investigation of these types of awareness with both neuroimaging evaluations and estimation of peripheral autonomic function are required as next steps for exploration of the relationship between awareness and human somatic states including somatic symptoms as well as general psychosomatic health.