Neurovegetative Decoupling in Somatoform Disorders : Biofeedback Interest (BIOFEESOMATO)

Neurovegetative Decoupling in the Visceral-brain Axis and Cognitive-emotional Vulnerability in Somatoform Disorders : Interest of Vagal Biofeedback

Laboratoire de Psychologie et NeuroCognition, Laboratoire interuniversitaire de psychologie : personnalité, cognition et changement social - LIP-PC2S

Evaluation of the physiological and clinical effects of the biofeedback training with patients suffering from somatoform disorders, depending on their neurovegetative profile related to a visceral-brain decoupling.

Somatoform disorders [SD] are defined as physiological function or organ disturbances unexplained by a specific diagnosis criterion. Some approaches have recently defended the idea of common factors of vulnerability behind the large variability of the clinical symptoms regarding the SD. In this context, the lead of the neurovegetative disturbances started receiving attention following some studies that suggested the autonomic nervous system [ANS] disturbances concerning a somatoform disorder, independently of its form. Two different neurovegetative endophenotypes (individual autonomic profiles) were highlighted: a functional neurovegetative profile (high vagal tone) and a dysfunctional neurovegetative profile (low vagal tone). A dysfunctional neurovegetative profile could be accompanied by a chronic decoupling in the brain-visceral axis according as the ANS is considered as a bidirectional communication system linked the central nervous system [CNS] and the viscera. Depending on the types of the neurovegetative profiles, different degrees of cognitive-emotional vulnerability and a higher or a lower level of acceptance of the illness could be supposed. Finally, recent findings defend the idea of the traumatic experiences as a determining factor to develop a SD. In accordance to the last notions regarding the SD, some therapeutic approaches could be interesting specifically techniques focusing on the vagal nerve. In this context, biofeedback [BFB] could provide a powerful method to restore the clinical and physiological impairments. As a consequence, the main objective is to evaluate the physiological and clinical effects of the BFB training with patients suffering from SD: Irritable Bowel Syndrome [IBS] or Psychogenic Non Epileptic Seizure [PNES]. The investigators make the prediction that the patients will be more or less responding to the biofeedback depending on their neurovegetative profile. A clustering will be performed in advance to identify the patients having a dysfunctional neurovegetative profile and patients having a functional neurovegetative profile. It will also permit to the investigators to confirm the hypothesis about the existence of two neurovegetative profiles related to a visceral-brain decoupling concerning the SD, independently of its form. To attest to it, 2 types of somatoform disorders will be analyzed: the irritable bowel syndrome manifesting by peripheral symptoms and the psychogenic non-epileptic seizures manifesting by central symptoms. Then the investigators will carry out a psycho-social exploration to demonstrate a higher cognitive-emotional vulnerability and a higher traumatic event incidence in this particular population, depending on their autonomic profiles.

Autonomic nervous system, Brain-gut axis, Endophenotype, Cognitive-emotional vulnerability, Traumas, Biofeedback, Heart rate variability, Vagal tone, Central nervous system, Enteric nervous system, Early life events, Somatoform disorders, Stress, Irritable bowel syndrome, Psychogenic non epileptic seizures

The study requires 3 sessions (T1 / T2 / T3) with at least 24 days between each. The period (24 days) between the first session and the second session (T1-T2) will be considered as the control period. During the period, the participants will practice none exercise. The period (24 days) between the second session and the third session (T2-T3) will be considered as the intervention period. At the end of the second session (T2), the participants will be separated into two inter-subject groups: an experimental group performing BFB technique (3X5 min per day) in the intervention period (T2-T3) and a control group not performing a specific exercise in the intervention period (T2-T3).

The participants won't be informed of the condition to which they belong. A debriefing will be done at the end of the last session (T3) for each participant.

The participants assigned to the experimental group will do the biofeedback training using the Emwave software during the intervention period (T2-T3). The biofeedback software (Emwave Pro®) includes a photoplethysmography sensor that can be positioned on the earlobe. The installation of the program and the explanations needed for using it, will be done during the second session (T2). According to the guidelines, a fractional training is proposed 5 minutes, 3 times a day for 24 days (T2-T3).

The participants assigned to the experimental group will not do a specific exercise during the intervention period (T2-T3).

BFB consists of a physiological recording used as a visual physiological feedback that can teach us how to control our physiology, which is naturally unconscious and uncontrollable. The BFB focused on the heart rate variability (HRV-BFB) could regulate the autonomic nervous system (vagal tone and sympathetic-parasympathetic balance) and the emotional state. The HRV BFB has received several clinical and experimental confirmations as a physiological remediation method. It is an innovative and non-pharmacological therapy frequently used to relieve stress.

High frequency (0.15-0.40 Hz), frequency-domain parameter HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

High frequency (0.15-0.40 Hz), frequency-domain parameter HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

High frequency (0.15-0.40 Hz), frequency-domain parameter HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Root mean square of successive RR interval differences, temporal-domain parameter RMSSD will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Root mean square of successive RR interval differences, temporal-domain parameter RMSSD will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Root mean square of successive RR interval differences, temporal-domain parameter RMSSD will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Low frequency (0.04-0.15 Hz), frequency-domain parameter LF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Low frequency (0.04-0.15 Hz), frequency-domain parameter LF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Low frequency (0.04-0.15 Hz), frequency-domain parameter LF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Spectral power of the low-frequency 0.1Hz band (0.075-0.108Hz), frequency-domain parameter LF-0.1Hz will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Spectral power of the low-frequency 0.1Hz band (0.075-0.108Hz), frequency-domain parameter LF-0.1Hz will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Spectral power of the low-frequency 0.1Hz band (0.075-0.108Hz), frequency-domain parameter LF-0.1Hz will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Total power of the 0-0.40 Hertz band, frequency-domain parameter Total power will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Total power of the 0-0.40 Hertz band, frequency-domain parameter Total power will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Total power of the 0-0.40 Hertz band, frequency-domain parameter Total power will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Ratio of LF to HF power, frequency-domain parameter LF/HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Ratio of LF to HF power, frequency-domain parameter LF/HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Ratio of LF to HF power, frequency-domain parameter LF/HF will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Standard deviation of all NN intervals, temporal-domain parameter SDNN will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Standard deviation of all NN intervals, temporal-domain parameter SDNN will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Standard deviation of all NN intervals, temporal-domain parameter SDNN will be measured using the electrocardiogram [ECG]: ECG data will be recorded using 3 single use and adhesive electrodes placed on the inner side of the right wrist, on the right shoulder and on the left side in accordance with the DII standard position (Einthoven). Physiological data recorded are related to the heart rate variability [HRV].

Skin conductance responses [SCR] frequency : number of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Skin conductance responses [SCR] frequency : number of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Skin conductance responses [SCR] frequency : number of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Skin conductance responses amplitude: amplitude of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Skin conductance responses amplitude: amplitude of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Skin conductance responses amplitude: amplitude of the spontaneous galvanic skin responses by periods SCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Integrated skin conductance responses [ISCR]: area of the galvanic skin responses identified on the signal ISCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Integrated skin conductance responses [ISCR]: area of the galvanic skin responses identified on the signal ISCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Integrated skin conductance responses [ISCR]: area of the galvanic skin responses identified on the signal ISCR will be measured using the Galvanic skin responses [GSR]: GSR data will be recorded using 2 skin sensors placed on the third phalanx of the forefinger and of the middle finger of the left hand. Physiological data recorded are related to the cholinergic sympathetic activity (tonic GSR / phasic GSR).

Pulsatility index variation [PI] : transit time flow PI will be measured using the Photoplethysmography [PPG]: PPG data will be recorded using a finger sensor. Physiological data recorded are related to the adrenergic sympathetic tone and allowing a record of the blood pulse waves associated with the heart rate.

Pulsatility index variation [PI] : transit time flow PI will be measured using the Photoplethysmography [PPG]: PPG data will be recorded using a finger sensor. Physiological data recorded are related to the adrenergic sympathetic tone and allowing a record of the blood pulse waves associated with the heart rate.

Pulsatility index variation [PI] : transit time flow PI will be measured using the Photoplethysmography [PPG]: PPG data will be recorded using a finger sensor. Physiological data recorded are related to the adrenergic sympathetic tone and allowing a record of the blood pulse waves associated with the heart rate.

Dominant power of the 0-0.15 Hertz band, frequency-domain parameter Dominant power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Dominant power of the 0-0.15 Hertz band, frequency-domain parameter Dominant power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Dominant power of the 0-0.15 Hertz band, frequency-domain parameter Dominant power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Total power of the 0-0.15 Hertz band, frequency-domain parameter Total power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Total power of the 0-0.15 Hertz band, frequency-domain parameter Total power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Total power of the 0-0.15 Hertz band, frequency-domain parameter Total power will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Slow-waves frequency per minute, frequency-domain parameter Slow-wave frequency will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Slow-waves frequency per minute, frequency-domain parameter Slow-wave frequency will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Slow-waves frequency per minute, frequency-domain parameter Slow-wave frequency will be measured using the electrogastrogram [EGG]: EGG data will be recorded using 6 single use and adhesive electrodes placed on the skin of the abdomen.

Delta frequency 0-4 Hertz band Delta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Delta frequency 0-4 Hertz band Delta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Delta frequency 0-4 Hertz band Delta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Theta frequency 4-7 Hertz band Theta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Theta frequency 4-7 Hertz band Theta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Theta frequency 4-7 Hertz band Theta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Alpha frequency 8-12 Hertz band Alpha frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Alpha frequency 8-12 Hertz band Alpha frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Alpha frequency 8-12 Hertz band Alpha frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Beta frequency 13-30 Hertz band Beta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Beta frequency 13-30 Hertz band Beta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Beta frequency 13-30 Hertz band Beta frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Gamma frequency >30 Hertz band Gamma frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Gamma frequency >30 Hertz band Gamma frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Gamma frequency >30 Hertz band Gamma frequency will be measured using the electroencephalogram [EEG]: EEG data will be recorded using a EEG headsets including 64 electrodes. The EEG is related to the brain activity generated by the neural functioning.

Alexithymia score will be measured using the Bermond-Vorst Alexithymia Questionnaire B version (BVAQ-B; Vorst & Bermond, 2001; French version Deborde et al., 2004). The subscale as considered as a trait scale including 20 items.

Neuroticism score will be measured using the Big Five Inventory-Neuroticism (BFI-N; John et al., 1991; French version Plaisant et al., 2005). The subscale as considered as a trait scale including 8 items.

The trai and state anxiety scores will be measured using the State-Trait Anxiety Inventory (STAI Y-AB) (Spielberger et al., 1983; French version Bruchon-Schweitzer & Paulhan, 1990). The scale includes 40 items.

The style of coping will be measured using the Brief Cope (Carver, 1997; French version Muller & Spitz, 2003). We will use it in its trait version. The subscale as considered as a trait scale including 28 items.

Positive affectivity score will be measured using the Positive And Negative Affect Schedule (PANAS; Watson et al., 1988; French version Caci & Bayle, 2007). To measure a global affective state, a score of positivity will be calculated by subtracting negative affect score from positive affect score. The subscale as considered as a state scale including 20 items.

Positive affectivity score will be measured using the Positive And Negative Affect Schedule (PANAS; Watson et al., 1988; French version Caci & Bayle, 2007). To measure a global affective state, a score of positivity will be calculated by subtracting negative affect score from positive affect score. The subscale as considered as a state scale including 20 items.

Positive affectivity score will be measured using the Positive And Negative Affect Schedule (PANAS; Watson et al., 1988; French version Caci & Bayle, 2007). To measure a global affective state, a score of positivity will be calculated by subtracting negative affect score from positive affect score. The subscale as considered as a state scale including 20 items.

The depressive symptoms score will be measured using the Center for Epidemiologic Studies-Depression Scale (CES-D; Radloff, 1977; French version Führer & Rouillon, 1989). The subscale as considered as a state scale including 20 items.

The depressive symptoms score will be measured using the Center for Epidemiologic Studies-Depression Scale (CES-D; Radloff, 1977; French version Führer & Rouillon, 1989). The subscale as considered as a state scale including 20 items.

The depressive symptoms score will be measured using the Center for Epidemiologic Studies-Depression Scale (CES-D; Radloff, 1977; French version Führer & Rouillon, 1989). The subscale as considered as a state scale including 20 items.

The perceived-stress level will be measured using the Perceived Stress Scale (PSS; Cohen et al., 1983; French version Bellighausen et al., 2009). The subscale as considered as a state scale including 10 items.

The perceived-stress level will be measured using the Perceived Stress Scale (PSS; Cohen et al., 1983; French version Bellighausen et al., 2009). The subscale as considered as a state scale including 10 items.

The perceived-stress level will be measured using the Perceived Stress Scale (PSS; Cohen et al., 1983; French version Bellighausen et al., 2009). The subscale as considered as a state scale including 10 items.

The coping flexibility score will be measured using the Coping Flexibility Scale (CFS; Kato, 2012). The CFS measures the coping flexibility including 10 items. The subscale as considered as a state scale.

The coping flexibility score will be measured using the Coping Flexibility Scale (CFS; Kato, 2012). The CFS measures the coping flexibility including 10 items. The subscale as considered as a state scale.

The coping flexibility score will be measured using the Coping Flexibility Scale (CFS; Kato, 2012). The CFS measures the coping flexibility including 10 items. The subscale as considered as a state scale.

The metacoping score will be measured using a visual analogue scale (VAS). The VAS was developed by ourselves to measure the perceived effectiveness of coping by asking: " how strategies used by yourself to cope with the situation were efficient? ". The participants will have to rate from 0 (no efficacy) to 10 (maximum of efficacy). The subscale as considered as a state scale.

The metacoping score will be measured using a visual analogue scale (VAS). The VAS was developed by ourselves to measure the perceived effectiveness of coping by asking: " how strategies used by yourself to cope with the situation were efficient? ". The participants will have to rate from 0 (no efficacy) to 10 (maximum of efficacy). The subscale as considered as a state scale.

The metacoping score will be measured using a visual analogue scale (VAS). The VAS was developed by ourselves to measure the perceived effectiveness of coping by asking: " how strategies used by yourself to cope with the situation were efficient? ". The participants will have to rate from 0 (no efficacy) to 10 (maximum of efficacy). The subscale as considered as a state scale.

The social support score will be measured using the Social Support Questionnaire short version (SSQ6; Sarason et al., 1987a; French version Bruchon-Schweitzer et al., 2003). The subscale as considered as a trait scale including 6 items.

The interceptive sensitivity score will be measured using the Multidimensional Assessment of Interoceptive Awareness second version (MAIA-2; Mehling et al., 2018). The subscale as considered as a trait scale including 37 items.

The life satisfaction score will be measured using the Satisfaction With Life Scale (SWLS; Diener et al., 1985; French version Blais et al., 1989). The subscale as considered as a state scale including 5 items.

The life satisfaction score will be measured using the Satisfaction With Life Scale (SWLS; Diener et al., 1985; French version Blais et al., 1989). The subscale as considered as a state scale including 5 items.

The life satisfaction score will be measured using the Satisfaction With Life Scale (SWLS; Diener et al., 1985; French version Blais et al., 1989). The subscale as considered as a state scale including 5 items.

The negative impact score will be measured using the Life Experiences Survey (LES; Sarason et al., 1978). The subscale as considered as a trait scale including 50 items. In this study a modified version of the LES will be used, whereby subjects documented the presence and perceived impact of adulthood life events that had occurred since 18 years of age to the time of completion of the survey. For the purposes of this study, 3 scores will be generated from this survey: the number of negatively perceived life events, the negative impact score determined by the sum of the impact scores of negatively perceived life events alone (higher scores indicate greater negative impact), and the total impact score determined by the sum of the impact scores of both negatively and positively perceived life events (higher scores indicate an overall more positive impact and lower scores indicate an overall more negative impact of all adulthood life events).

The frequency, severity and intensity scores will be measured using the Daily Hassles Scale (DHS; Kanner et al., 1981). The subscale as considered as a trait scale including 117 items.

The child abuse scores will be measured using the Childhood Trauma Questionnaire-Short Form (CTQ; Bernstein et al., 2003). The subscale as considered as a trait scale including 28 items.

The acceptance score will be measured using the Illness Cognition Questionnaire for chronic disease (ICQ-18; Evers et al., 2001). The subscale as considered as a state scale including 18 items.

The acceptance score will be measured using the Illness Cognition Questionnaire for chronic disease (ICQ-18; Evers et al., 2001). The subscale as considered as a state scale including 18 items.

The acceptance score will be measured using the Illness Cognition Questionnaire for chronic disease (ICQ-18; Evers et al., 2001). The subscale as considered as a state scale including 18 items.

Inclusion Criteria: Somatoform disorders (IBS or PNES) diagnosis must be established by the partner doctors Participants must have home computer Participants must be of the age of majority Participants must be registered for social security Participants must have signed an informed consent Exclusion Criteria: Specially protected participants (under clauses L1121-5 and L1121-8 by the code of public health): juveniles, pregnant womens, nursing mothers, law's protection peoples Participants suffering from a severe psychiatric disease needing specialised attention Participants suffering from or have suffered from a severe disease causing autonomic dysfunctions (heart failure, asthma, blood disease, renal failure, peripheral neuropathy, vagotomy, thyroid disorder, alcoholism, liver disease, amyloidosis) Participants taking medication which could be impact autonomic nervous system activity (anticholinergic, antiarrhythmics, clonidine, beta-blockers, tricyclic anti-depressants, metronidazole) Participants placing under judicial or administrative supervisions Participants were compensated more than 4500 euros because of his research protocol participation concerning human over the 12 months prior to the actual study Participants being not be able to contact in emergency Participants being in an exclusion period from another study

Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation. 1996 Mar 1;93(5):1043-65. No abstract available.

Laborde S, Mosley E, Thayer JF. Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research - Recommendations for Experiment Planning, Data Analysis, and Data Reporting. Front Psychol. 2017 Feb 20;8:213. doi: 10.3389/fpsyg.2017.00213. eCollection 2017.

Muller L, Spitz E. [Multidimensional assessment of coping: validation of the Brief COPE among French population]. Encephale. 2003 Nov-Dec;29(6):507-18. French.

Mehling WE, Acree M, Stewart A, Silas J, Jones A. The Multidimensional Assessment of Interoceptive Awareness, Version 2 (MAIA-2). PLoS One. 2018 Dec 4;13(12):e0208034. doi: 10.1371/journal.pone.0208034. eCollection 2018.

Varon C, Morales J, Lazaro J, Orini M, Deviaene M, Kontaxis S, Testelmans D, Buyse B, Borzee P, Sornmo L, Laguna P, Gil E, Bailon R. A Comparative Study of ECG-derived Respiration in Ambulatory Monitoring using the Single-lead ECG. Sci Rep. 2020 Mar 31;10(1):5704. doi: 10.1038/s41598-020-62624-5.

de Vroege L, Emons WHM, Sijtsma K, van der Feltz-Cornelis CM. Psychometric Properties of the Bermond-Vorst Alexithymia Questionnaire (BVAQ) in the General Population and a Clinical Population. Front Psychiatry. 2018 Apr 23;9:111. doi: 10.3389/fpsyt.2018.00111. eCollection 2018.

Bulut NS, Wurz A, Yorguner Kupeli N, Carkaxhiu Bulut G, Sungur MZ. Heart rate variability response to affective pictures processed in and outside of conscious awareness: Three consecutive studies on emotional regulation. Int J Psychophysiol. 2018 Jul;129:18-30. doi: 10.1016/j.ijpsycho.2018.05.006. Epub 2018 May 19.

Schumann A, Kohler S, Brotte L, Bar KJ. Effect of an eight-week smartphone-guided HRV-biofeedback intervention on autonomic function and impulsivity in healthy controls. Physiol Meas. 2019 Jul 1;40(6):064001. doi: 10.1088/1361-6579/ab2065.

Sarason IG, Johnson JH, Siegel JM. Assessing the impact of life changes: development of the Life Experiences Survey. J Consult Clin Psychol. 1978 Oct;46(5):932-46. doi: 10.1037//0022-006x.46.5.932. No abstract available.

Watson D, Clark LA, Tellegen A. Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol. 1988 Jun;54(6):1063-70. doi: 10.1037//0022-3514.54.6.1063.

Vorst, Harrie C.M, et Bob Bermond. " Validity and Reliability of the Bermond-Vorst Alexithymia Questionnaire ". Personality and Individual Differences 30, no 3 (février 2001): 413 34.

Plaisant O, Srivastava S, Mendelsohn GA, Debray Q, John OP. Relations entre le Big Five Inventory franc¸ais et le manuel diagnostique des troubles mentaux dans un échantillon clinique franc¸ais. Ann Med Psychol 2005;163:161-7.

Radloff LS. The CES-D scale: a self report depression scalefor research in the general population. App Psycho Meas1977;1:384-401.