Physical activity and respiratory behavior in daily life of patients with panic disorder and healthy controls

Cardiorespiratory Assessments in Panic Disorder Facilitated by Wearable Devices: A Systematic Review and Brief Comparison of the Wearable Zephyr BioPatch with the Quark-b2 Stationary Testing System

Abnormalities in cardiorespiratory measurements have repeatedly been found in patients with panic disorder (PD) during laboratory-based assessments. However, recordings performed outside laboratory settings are required to test the ecological validity of these findings. Wearable devices, such as sensor-imbedded garments, biopatches, and smartwatches, are promising tools for this purpose. We systematically reviewed the evidence for wearables-based cardiorespiratory assessments in PD by searching for publications on the PubMed, PsycINFO, and Embase databases, from inception to 30 July 2022. After the screening of two-hundred and twenty records, eight studies were included. The limited number of available studies and critical aspects related to the uncertain reliability of wearables-based assessments, especially concerning respiration, prevented us from drawing conclusions about the cardiorespiratory function of patients with PD in daily life. We also present preliminary data on a pilot study conducted on volunteers at the Villa San Benedetto Menni Hospital for evaluating the accuracy of heart rate (HR) and breathing rate (BR) measurements by the wearable Zephyr BioPatch compared with the Quark-b2 stationary testing system. Our exploratory results suggested possible BR and HR misestimation by the wearable Zephyr BioPatch compared with the Quark-b2 system. Challenges of wearables-based cardiorespiratory assessment and possible solutions to improve their reliability and optimize their significant potential for the study of PD pathophysiology are presented.

The psychophysiology of the sigh: II: The sigh from the psychological perspective

A sigh is a distinct respiratory behavior with specific psychophysiological roles. In two accompanying reviews we will discuss the physiological and psychological functions of the sigh. The present review will focus on the psychological functions of the sigh. We discuss the regulatory effects of a sigh, and argue how these effects may become maladaptive when sighs occur excessively. The adaptive role of a sigh is discussed in the context of regulation of psychophysiological states. We propose that sighs facilitate transitions from one psychophysiological state to the next, and this way contribute to psychophysiological flexibility, via a hypothesized resetting mechanism. We discuss how a sigh resets respiration, by controlling mechanical and metabolic properties of respiration associated with respiratory symptoms. Next, we elaborate on a sigh resetting emotional states by facilitating emotional transitions. We attempt to explain the adaptive and maladaptive functions of a sigh in the framework of stochastic resonance, in which we propose occasional, spontaneous sighs to be noise contributing to psychophysiological regulation, while excessive sighs result in psychophysiological dysregulation. In this context, we discuss how sighs can contribute to therapeutic interventions, either by increasing sighs to improve regulation in case of a lack of sighing, or by decreasing sighs to restore regulation in case of excessive sighing. Finally, a research agenda on the psychology of sighs is presented.

The Accuracy of Tidal Volume Measured With a Smart Shirt During Tasks of Daily Living in Healthy Subjects: Cross-sectional Study

Background

The Hexoskin is a smart shirt that can take continuous and objective measurements and could be part of a potential telemonitoring system.

Objective

The aim of this study was to determine the accuracy of the calibrated Hexoskin in measuring tidal volumes (TVs) in comparison to spirometry during various tasks.

Methods

In a cross-sectional study, the TV of 15 healthy subjects was measured while performing seven tasks using spirometry and the Hexoskin. These tasks were performed during two sessions; between sessions, all equipment was removed. A one-time spirometer-based calibration per task was determined in session 1 and applied to the corresponding task in both sessions. Bland-Altman analysis was used to determine the agreement between TV that was measured with the Hexoskin and that measured with spirometry. A priori, we determined that the bias had to be less than ±5%, with limits of agreement (LOA) of less than ±15%. Lung volumes were measured and had to have LOA of less than ±0.150 L.

Results

In the first session, all tasks had a median bias within the criteria (±0.6%). In the second session, biases were ±8.9%; only two tasks met the criteria. In both sessions, LOA were within the criteria in six out of seven tasks (±14.7%). LOA of lung volumes were greater than 0.150 L.

Conclusions

The Hexoskin was able to correctly measure TV in healthy subjects during various tasks. However, after reapplication of the equipment, calibration factors were not able to be reused to obtain results within the determined boundaries.

Trial Registration

Netherlands Trial Register NL6934; https://www.trialregister.nl/trial/6934

Inductive plethysmography potential as a surrogate for ventilatory measurements during rest and moderate physical exercise

Background:

Portable respiratory inductive plethysmography (RIP) systems have been validated for ventilatory assessment during resting conditions and during incremental treadmill exercise. However, in clinical settings and during field-based exercise, intensity is usually constant and submaximal. A demonstration of the ability of RIP to detect respiratory measurements accurately during constant intensity conditions would promote and validate the routine use of portable RIP devices as an alternative to ergospirometry (ES), the current gold standard technique for ventilatory measures.

Objective:

To investigate the agreement between respiratory variables recorded by a portable RIP device and by ES during rest and constant intensity exercise.

Method:

Tidal volume (V_T), respiratory rate (RR) and minute ventilation (V_E) were concurrently acquired by portable RIP and ES in seven healthy male volunteers during standing rest position and constant intensity treadmill exercise.

Results:

Significant agreement was found between RIP and ES acquisitions during the standing rest position and constant intensity treadmill exercise for RR and during the standing rest position for V_E.

Conclusion:

Our results suggest that portable RIP devices might represent a suitable alternative to ES during rest and during constant submaximal exercise.

Metabolic decoupling in daily life in patients with panic disorder and agoraphobia

Various studies have assessed autonomic and respiratory underpinnings of panic attacks, yet the psychophysiological functioning of panic disorder (PD) patients has rarely been examined under naturalistic conditions at times when acute attacks were not reported. We hypothesized that emotional activation in daily life causes physiologically demonstrable deviations from efficient metabolic regulation in PD patients. Metabolic coupling was estimated as within-individual correlations between heart rate (HR) and indices of metabolic activity, i.e., physical activity (measured by 3-axial accelerometry, Acc), and minute ventilation (Vm, measured by calibrated inductive plethysmography, as proxy for oxygen consumption). A total of 565 daytime hours were recorded in 19 PD patients and 20 healthy controls (HC). Pairwise cross-correlations of minute-by-minute averages of these metabolic indices were calculated for each participant and then correlated with several indices of self-reported anxiety. Ambulatory HR was elevated in PD (p = .05, d = 0.67). Patients showed reduced HR-Acc (p < .006, d = 0.97) and HR-Vm coupling (p < .009, d = 0.91). Combining Vm and Acc to predict HR showed the strongest group separation (p < .002, d = 1.07). Discriminant analyses, based on the combination of Vm and Acc to predict HR, classified 77% of all participants correctly. In PD, HR-Acc coupling was inversely related to trait anxiety sensitivity, as well as tonic and phasic daytime anxiety. The novel method that was used demonstrates that anxiety in PD may reduce efficient long-term metabolic coupling. Metabolic decoupling may serve as physiological characteristic of PD and might aid diagnostics for PD and other anxiety disorders. This measure deserves further study in research on health consequences of anxiety and psychosocial stress.

Are respiratory abnormalities specific for panic disorder? A meta-analysis

OBJECTIVES

There is evidence of baseline respiratory abnormalities in panic disorder (PD), but whether they are specific to PD remains unclear. To investigate this issue, we meta-analyzed results from studies comparing baseline respiratory and hematic variables between subjects with PD and subjects with other anxiety disorders.

METHODS

A literature search in bibliographic databases was performed. Fixed-effects models were applied. Several moderator analyses and publication bias diagnostics were performed.

RESULTS

We found: (1) significantly lower mean end-tidal partial pressure of CO(2) (et-pCO(2)) in subjects with PD than in those with social phobia (SP) or generalized anxiety disorder (GAD), and (2) higher mean respiratory rate, lower venous et-pCO(2) and HCO(3)(-) concentration in subjects with PD than in those with SP. No publication bias was found.

CONCLUSIONS

Subjects with PD show a condition of baseline hyperventilation when compared to subjects with SP or GAD. Hematic variables suggest that the hyperventilation may be chronic. These results support the idea that baseline respiratory abnormalities are specific to PD pathophysiology. Further studies are needed to clarify whether these abnormalities are related to a malfunction of the respiratory system or to specific cognitive/emotional/behavioral factors in this population.

Phosphate levels as a possible state marker in panic disorder: preliminary study of a feasible laboratory measure for routine clinical practice

OBJECTIVE

Low serum phosphate level is considered one of the metabolic adaptations to the respiratory alkalosis induced by hyperventilation associated with panic disorder. The aim of this study was to assess phosphatemia as a possible state marker for panic disorder.

METHODS

Sixteen panic disorder patients underwent clinical assessment with a semi-structured interview, a set of rating scales and the self-rated State and Trait Anxiety Inventory (STAI), as well as extraction of venous blood samples at baseline and after 12 weeks of pharmacological treatment. Ten healthy volunteers of similar sex, age and educational level filled out the STAI and gave blood samples at baseline and 12 weeks later.

RESULTS

The median (25th-75th percentiles) of phosphate levels (mg/dl) was 2.68 (2.22-3.18) among patients and 4.13 (3.74-4.70) among healthy volunteers respectively (P < 0.001). Seven (44%) patients and no healthy volunteers presented low serum phosphate (<2.50 mg/dl) at baseline; this patient abnormality was corrected in all cases after successful treatment. At baseline, the age-adjusted correlation between phosphate levels and state-anxiety was -0.66 (P < 0.001) among all 26 participants and -0.51 (P = 0.05) among the 16 panic disorder patients.

CONCLUSIONS

Measurement of phosphate levels could be easily introduced into clinical practice as a possible marker for chronic hyperventilation in panic disorder, although further investigations with larger sample sizes are necessary to characterize panic disorder patients with low versus normal phosphate levels.

Reexperiencing symptoms, dissociation, and avoidance behaviors in daily life of patients with PTSD and patients with panic disorder with agoraphobia

Panic attacks are frequently perceived as life threatening. Panic disorder (PD) patients may therefore experience symptoms of posttraumatic stress disorder (PTSD). The authors explored this in 28 healthy controls, 17 PTSD patients, and 24 PD patients with agoraphobia who completed electronic diaries 36 times during 1 week. Patient groups frequently reported dissociation as well as thoughts, memories, and reliving of their trauma or panic attacks. PTSD patients reported more trauma/panic attack thoughts (incidence rate ratio [IRR] = 2.9) and memories (IRR = 2.8) than PD patients. Patient groups relived their trauma or panic attacks equally frequently, and reported comparable bodily reactions and distress associated with trauma or panic attack memories. Clinical groups avoided trauma or panic attack reminders more often than healthy controls (avoidance of trauma- or panic attack-related thoughts (IRR = 8.0); avoidance of things associated with the trauma or panic attack (IRR = 40.7). PD patients avoided trauma or panic attack reminders less often than PTSD patients (avoidance of trauma- or panic attack-related thoughts [IRR = 2.5]; avoidance of things associated with the trauma or panic attack [IRR = 4.1]), yet these differences were nonsignificant when controlling for functional impairment. In conclusion, trauma-like symptoms are common in PD with agoraphobia and panic attacks may be processed similarly as trauma in PTSD.

Baseline respiratory parameters in panic disorder: a meta-analysis

BACKGROUND

The presence of abnormalities in baseline respiratory function of subjects with panic disorder (PD) is expected according to PD respiratory theories. We aimed to meta-analyze results from studies comparing baseline respiratory and hematic parameters related to respiration between subjects with PD and controls.

METHODS

A literature research in bibliographic databases was performed. Fixed-effects models were applied for all parameters while random-effects models only when suitable (at least 10 independent studies). Several moderator analyses and publication bias diagnostics were performed.

RESULTS

We found significantly higher mean minute ventilation and lower et-pCO(2) in subjects with PD than controls. Moreover we also found evidences of reduced HCO(3)(-) and PO(4)(-) hematic concentrations, higher indexes of respiratory variability/irregularity and higher rate of sighs and apneas. Evidence of heterogeneity was partly explained by moderator analyses. No relevant publication bias was found.

LIMITATIONS

Several shortcomings affected the included studies, such as over-inclusive recruitment criteria, samples unbalanced for socio-demographic characteristics, lack of statistical details and small number of studies available for several parameters.

DISCUSSION

Our results support the idea of abnormalities in respiratory function of subjects with PD. Compared to controls, they showed baseline hyperventilation; the results from hematic parameters suggest that hyperventilation may be chronic and not simply caused by their high anxiety levels during respiratory assessment. Evidences of higher variability and irregularity in respiratory patterns of subjects with PD were also found. It is unclear to what extent the higher rate of sighs and apneas may explain the other baseline respiratory abnormalities found in PD.

Prevalence of the metabolic syndrome in patients with borderline personality disorder: results from a cross-sectional study

Metabolic syndrome (MetS) is an important risk factor for the development of type-2 diabetes and coronary artery disease. We aimed to compare the MetS prevalence in patients with borderline personality disorder (BPD) with comparison subjects followed in primary care from a similar region. One hundred and thirty-five BPD patients according to DSM-IV diagnostic criteria were compared to 1009 subjects from primary care. We used the American Heart Association/National Heart, Lung and Blood Institute criteria to determine the rate of MetS. The age-standardized prevalence of MetS was more than double in patients with BPD compared to comparison subjects (23.3 vs. 10.6 %, p < 0.05). Regarding individual MetS criteria, hyperglycemia was significantly more prevalent in both genders (p < 0.05). Abdominal obesity (p < 0.05) and hypertriglyceridemia (p < 0.05) were significantly higher only in women with BPD. Within BPD patients, an increased rate of MetS was associated with higher BMI (p = 0.004), age (p = 0.03), treatment with second-generation antipsychotics (quetiapine, olanzapine and clozapine; p = 0.032), dysthymia (p = 0.031), panic disorder (p = 0.032), benzodiazepine dependency (p = 0.015) and binge eating disorder p = 0.02). Our results demonstrate an increased MetS rate, dysregulated glucose and lipid metabolism in patients with BPD. Cardiometabolic monitoring and careful screening for physical health conditions among people with BPD is warranted.

A sigh following sustained attention and mental stress: effects on respiratory variability

Normal breathing consists of considerable correlated variability (parameters of subsequent breaths are correlated) and some random variability. Emotional and attentive states alter normal breathing variability, which can be restored by a sigh. The present study aimed to investigate the effects of mental arithmetic and sustained attention on respiratory variability. In addition, the effect of a spontaneous sigh following both conditions was examined, compared to an instructed sigh and a control maneuver. Mental arithmetic and sustained attention were characterized by decreased correlated and total breathing variability, respectively. A spontaneous sigh restored correlated variability. An instructed sigh restored correlated variability following mental arithmetic, and increased total variability following sustained attention. These results suggest that a spontaneous sigh and an instructed sigh, when physiologically appropriate, restore respiratory variability influenced by stress or attention.

The Significance of Transcutaneous Continuous Overnight CO(2) Monitoring in Determining Initial Mechanical Ventilator Application for Patients with Neuromuscular Disease

Objective

To reveal the significance of continuous transcutaneous carbon dioxide (CO₂) level monitoring through reviewing cases which showed a discrepancy in CO₂ levels between arterial blood gas analysis (ABGA) and continuous transcutaneous blood gas monitoring.

Method

Medical record review was conducted retrospectively of patients with neuromuscular diseases who had started home mechanical ventilation between June 2008 and May 2010. The 89 patients underwent ABGA at the 1st hospital day, and changes to their CO₂ level were continuously monitored overnight with a transcutaneous blood gas analysis device. The number of patients who initially appeared to show normal PaCO₂ through ABGA, yet displayed hypercapnea through overnight continuous monitoring, was counted.

Results

36 patients (40.45%) presented inconsistent CO₂ level results between ABGA and continuous overnight monitoring. The mean CO₂ level of the 36 patients using ABGA was 37.23±5.11 mmHg. However, the maximum and mean CO₂ levels from the continuous monitoring device were 52.25±6.87 mmHg and 46.16±6.08 mmHg, respectively. From the total monitoring period (357.28±150.12 minutes), CO₂ retention over 45 mmHg was detected in 198.97 minutes (55.69%).

Conclusion

Although ABGA only reflects ventilatory status at the puncturing moment, ABGA results are commonly used to monitor ventilatory status in most clinical settings. In order to decide the starting point of home mechanical ventilation in neuromuscular patients, continuous overnight monitoring should be considered to assess latent CO₂ retention.

Instability of physical anxiety symptoms in daily life of patients with panic disorder and patients with posttraumatic stress disorder

The present study examined severity as well as degree and temporal pattern of instability of DSM-IV-based bodily symptoms of anxiety (BSA) in daily life of 26 panic disorder (PD) patients, 17 posttraumatic stress disorder (PTSD) patients, and 28 healthy controls (HC) during 1 week, using electronic diaries. The ecological momentary assessment around every 3h during wake times was accepted well by patients. Compared to HC, patient groups exhibited elevated instability of BSA. BSA instability was more pronounced in PTSD than PD (p<0.005), even after controlling for mean symptom level. Numbers of symptomatic episodes were comparable in PTSD and PD, but the duration of symptom-free episodes was shorter in PTSD than PD. Results indicate that PTSD patients are particularly burdened by fluctuations in somatic symptoms of anxiety, implying perceived unpredictability and uncontrollability. Electronic diaries can be applied in innovative ways to provide novel insights into the phenomenology of anxiety disorders that may not be captured well by retrospective interviews and questionnaires.

Temporal stability and coherence of anxiety, dyspnea, and physiological variables in panic disorder

Twenty-five panic disorder (PD) patients, 19 social phobics (SP), and 20 healthy controls (HC) sat quietly for 15 min, rating their anxiety and dyspnea every 30s while respiratory, cardiovascular, and electrodermal responses were recorded. No panic attacks were reported. For self-reported anxiety and dyspnea, within-subject variability over time was higher in PD than in SP or HC. In PD within-subject correlations across 30-s epochs were significant for (a) self-reported anxiety versus dyspnea, end-tidal pCO2, minute volume, duty cycle, skin conductance level, and interbeat interval, and for (b) dyspnea versus end-tidal pCO2, minute volume, tidal volume, and inspiratory flow rate. Several positive or negative correlations were greater in PD than in other groups. Thus in PD, experienced anxiety and dyspnea are temporally unstable but are correlated with each other and with fluctuations in respiratory and autonomic variables, even in the absence of panic attacks.