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A paradigm was developed to experimentally investigate the dysregulation of affective reactivity in clinical depression. The literature so far reported evidence for three directions of dysregulation - negative potentiation, positive attenuation, and emotion context insensitivity. Therefore a paradigm was designed to allow to test all three hypotheses simultaneously. Furthermore, to enable generalization across the specific stimuli used in the experiment, stimuli of two sensory modalities were used - pictures and sounds. Because it was hypothesized, that the specificity of affective reactivity of depressed patients will be especially prominent in long lasting affective situations, a categorically blocked presentation mode was chosen. Regarding the dependent variables, a multimethod approach was conducted. Besides self-report ratings of the feeling state, startle responses, skin conductance responses, heart rate, and the electromyogram of the corrugator and zygomatic muscle were recorded. In a separate session, BOLD-responses during picture viewing were collected by functional magnetic resonance imaging (fMRI). Both sessions were conducted with three samples: a healthy student sample, a depressed outpatient sample, and a healthy age and gender matched control sample. The results of the patient sample support an integration of the emotion context insensitivity and the negative potentiation hypothesis. Patients reported generally to feel more unpleasant and more aroused than healthy controls. Skin conductance and startle responses were modulated by valence to a smaller degree in the patients than in the controls. No group differences were found in the facial muscle activity. BOLD-responses were potentiated during unpleasant compared to neutral pictures in the patient but not in the control group in the amygdala, the insular cortex and the orbito frontal cortex. A model to integrate these results is developed. Its central assumption is, that the inability to respond to affective stimuli is an aversive experience and therefore leads to a negativity bias in attention and cognition. Direction of further research and implications for psychotherapies are discussed.
Brain aging even in healthy older adults is characterized by a decline in cognitive functions including memory, learning and attention. Among others, memory is one of the major cognitive functions affected by aging. Understanding the mechanisms underlying age-related memory decline may help pave the road for novel treatment strategies. Here, we tried to elucidate the neural correlates associated with memory decline using structural and functional neuroimaging and neuromodulation with transcranial direct current stimulation (tDCS).
Over the course of three studies, we investigated 1) the influence of white matter integrity and grey matter volume on memory performance in healthy older adults, 2) the role of functional coupling within the memory network in predicting memory performance and the impact of tDCS in modulating retrieval performance in healthy older adults, 3) the effect of tDCS over the sensorimotor cortex on cognitive performance in young adults.
MRI was used to study associations of cognitive performance with white matter integrity and grey matter volume, and examine their causal relationship in the course of aging. White matter integrity was assessed by acquiring diffusion tensor imaging (DTI) and performing deterministic tractography based on constrained spherical deconvolution. Grey matter volume was estimated using fully automated segmentation. Both white matter integrity and grey matter volume were correlated with behavioral data of a verbal episodic memory task. Percentage of correct answers at retrieval was used to measure memory performance (Manuscript 1). In addition, anodal tDCS (atDCS) (1 mA, 20 min) was applied over CP5 (left temporoparietal cortex) to modulate memory formation in healthy older adults. Participants underwent resting-state fMRI before the stimulation. Functional connectivity analysis was performed to determine whether functional coupling within the memory network predicted initial memory performance, and to examine its association to tDCS-induced enhancement effect (Manuscript 2). Finally, atDCS (1 mA, 20 min) was applied over C3 (left sensorimotor cortex) to explore the effect of tDCS over the sensorimotor cortex on cognitive performance in young adults. During the stimulation, participants performed three tasks; gestural task, attentional load task and simple reaction time task (Manuscript 3).
Results showed that volumes of the left dentate gyrus (DG) and tractography-based fractional anisotropy (FA) of individual fornix pathways were positively related to memory retrieval in older adults. Brain-behavior associations were observed for correct rejections rather than hits of memory performance, indicating specificity of memory network functioning for detecting false associations. Thus, the data suggested a particular role of neural integrity that promotes successful memory retrieval in older adults. Subsequent mediation analysis showed that left DG volume mediated the effect of fornix FA on memory performance (48%), corrected for age, revealing a crucial role of hippocampal pathway microstructure in modulating memory performance in older adults (Manuscript 1). tDCS results showed that atDCS led to better retrieval performance and increasing learning curves, indicating that brain stimulation can induce plasticity of episodic memory processes in older adults. Combining tDCS and fMRI, hippocampo-temporoparietal functional connectivity was positively associated with initial memory performance in healthy older adults and was positively correlated with the magnitude of individual tDCS-induced enhancement, suggesting that individual tDCS responsiveness may be determined by intrinsic network coupling (Manuscript 2). Finally, our findings suggested that atDCS over left sensorimotor cortex reduced reaction times in the gestural-verbal integration task, specifically for incongruent pairs of gestures and verbal expressions, indicating the role of sensorimotor cortex in gestural-verbal integration in young adults (Manuscript 3).
The results of all three studies may help to elucidate age-related structural deterioration and functional coupling network underlying cognitive processes in healthy adults. Furthermore, these studies emphasized the importance of interventions like tDCS in modulating cognitive performance, specifically episodic verbal memory and gestural-verbal integration. By unveiling the specific role of brain structures and functional network coupling as well as the role of tDCS in modulating cognitive performance, our results contribute to a better understanding of brain-behavior associations, and may help to develop clinical interventional approaches, tailored for specific cognitive functions in aging.
Introduction: The Cognitive Behavioral Analysis System of Psychotherapy (CBASP) was developed for the treatment of persistent depressive disorder (PDD), where comorbid personality disorders (PD) are common. In contrast to other PD, comorbid borderline personality disorder (BPD) is often regarded as an exclusion criterion for CBASP. In clinical settings, however, subthreshold BPD symptoms are prevalent in PDD and may not be obvious at an initial assessment prior to therapy. As data on their impact on CBASP outcome are very limited, this naturalistic study investigates BPD features in PDD and their relevance for the therapeutic outcome of a multimodal CBASP inpatient program.
Method: Sixty patients (37 female, mean age 38.3, SD 11.9 years) meeting DSM-5 criteria for PDD underwent a 10 weeks CBASP inpatient program. BPD features (i.e., number of fulfilled DSM-5 criteria) together with childhood maltreatment and rejection sensitivity were assessed on admission. Before and after treatment, severity of depressive symptoms was measured using the Montgomery-Asberg Depression Rating Scale (MADRS) and the Beck Depression Inventory (BDI-II). BPD symptoms were assessed using the Borderline Personality Disorder Severity Index (BPDSI-IV) and the Borderline Symptom List (BSL-23). Intercorrelations of baseline characteristics and symptom change during treatment were analyzed.
Results: Patients with PDD met a mean of 1.5 (SD 1.6) BPD criteria with 4 patients fulfilling ≥5 criteria. BPD symptoms and depressive symptoms showed a strong correlation, and BPD symptoms were additionally correlated with emotional abuse and rejection sensitivity. There was no association between BPD features at baseline and improvement on the MADRS, however, BPD features tended to be associated with a lower response according to the BDI-II score after 10 weeks of treatment. Furthermore, BPD symptoms (i.e., abandonment, impulsivity and affective instability) were reduced after 10 weeks of CBASP treatment.
Discussion: BPD symptoms are prevalent in patients with PDD and highly intertwined with the experience of depressive symptoms. In this naturalistic study in PDD, BPD features at baseline did not limit the clinical response to CBASP. Future studies may extend the spectrum of PDD to comorbid subsyndromal or even syndromal BPD in order to develop tailored psychotherapeutic treatment for these complex affective disorders.
Background: Interpersonal skills deficits and dysfunctional metacognitive beliefs have been implicated in the etiology and maintenance of depression. This study aimed to investigate the association between changes in these skills deficits and change in depressive symptoms over the course of treatment with Cognitive Behavioral Analysis System of Psychotherapy (CBASP) and Metacognitive Therapy (MCT).
Methods: In this prospective, parallel group observational study, data was collected at baseline and after 8 weeks of an intensive day clinic psychotherapy program. Based on a shared decision between patients and clinicians, patients received either CBASP or MCT. Ninety patients were included in the analyses (CBASP: age M = 38.7, 40.5% female, MCT: age M = 44.7, 43.3% female). Interpersonal deficits were assessed with the short-form of the Luebeck Questionnaire for Recording Preoperational Thinking (LQPT-SF) and the Impact Message Inventory (IMI-R). Metacognitive beliefs were assessed with the Metacognition Questionnaire-30 (MCQ-30). The Quick Inventory of Depressive Symptomatology (QIDS-SR16) was utilized to assess depressive symptoms. A regression analysis was conducted to assess variables associated with outcome. ANCOVAs were utilized to investigate whether improvement in skills deficits is dependent on type of treatment received.
Results: Improvements in preoperational thinking and increases in friendly-dominant behavior were associated with change in depressive symptoms. There was no association between reductions in dysfunctional metacognitive beliefs and a decrease in depressive symptoms. While both treatment groups showed significant improvements in interpersonal and metacognitive skills, there was no significant between-group difference in the change scores for either of these skills.
Conclusion: Our findings suggest that changes in interpersonal skills seem to be of particular relevance in the treatment of depression. These results have to be replicated in a randomized-controlled design before firm conclusions can be drawn.
Individual responses to behavioral treatment of anxiety disorders vary considerably, which requires a better understanding of underlying processes. In this study, we examined the violation and change of threat beliefs during exposure. From 8,484 standardized exposure records of 605 patients with different anxiety disorders, learning indicators were derived: expectancy violation as mismatch between threat expectancy before exposure and threat occurrence, expectancy change as difference between original and adjusted expectancy after exposure, and prediction-error learning rate as extent to which expectancy violation transferred into change. Throughout sessions, high threat expectancy but low occurrence and adjusted expectancy indicated successful violation and change of threat beliefs by exposure. Expectancy violation, change, and learning rate substantially varied between patients. Not expectancy violation itself, but higher learning rate and expectancy change predicted better treatment outcome. Successful exposure thus requires expectancy violation to induce actual expectancy change, supporting learning from prediction error as transdiagnostic mechanism underlying successful exposure therapy.
Body dissatisfaction is pervasive among young women in Western countries. Among the many forces that contribute to body dissatisfaction, the overrepresentation of thin bodies in visual media has received notable attention. In this study, we proposed that prevalence-induced concept change may be one of the cognitive mechanisms that explain how beauty standards shift. We conducted a preregistered online experiment with young women (N = 419) and found that when the prevalence of thin bodies in the environment increased, the concept of being overweight expanded to include bodies that would otherwise be judged as “normal.” Exploratory analyses revealed significant individual differences in sensitivity to this effect, in terms of women’s judgments about other bodies as well as their own. These results suggest that women’s judgments about other women’s bodies are biased by an overrepresentation of thinness and lend initial support to policies designed to increase size-inclusive representation in the media.
Children as young as 3 years can remember an object’s location within an arrangement and can retrieve it from a novel viewpoint (Nardini et al., 2006). However, this ability is impaired if the arrangement is rotated to compensate for the novel viewpoint, or, if the arrangement is rotated and children stand still. There are two dominant explanations for this phenomenon: self-motion induces an automatic spatial updating process which is beneficial if children move around the arrangement, but misleading if the children’s movement is matched by the arrangement and not activated if children stand still and only the arrangement is moved (see spatial updating; Simons and Wang, 1998). Another explanation concerns reference frames: spatial representations might depend on peripheral spatial relations concerning the surrounding room instead on proximal relations within the arrangement, even if these proximal relations are sufficient or more informative. To evaluate these possibilities, we rotated children (N = 120) aged between 3 and 6 years with an occluded arrangement. When the arrangement was in misalignment to the surrounding room, 3- and 4-year-olds’ spatial memory was impaired and 5-year-olds’ was lightly impaired suggesting that they relied on peripheral references of the surrounding room for retrieval. In contrast, 6-years-olds’ spatial representation seemed robust against misalignment indicating a successful integration of spatial representations.
Given the increasing prevalence of chronic kidney disease (CKD) and its impact on health care, it is important to better understand the multiple factors influencing health-related quality of life (HRQOL), particularly since they have been shown to affect CKD outcomes. Determinants of HRQOL as measured by the validated Kidney Disease Quality of Life questionnaire (KDQOL) and the Patient Health Questionnaire depression screener (PHQ-9) were assessed in a routine CKD patient sample, the Greifswald Approach to Individualized Medicine (GANI_MED) renal cohort (N = 160), including a wide range of self-reported data, sociodemographic and laboratory measures. Compared to the general population, CKD patients had lower HRQOL indices. Dialysis was associated with (1) low levels of physical functioning, (2) increased impairments by symptoms and problems, and (3) more effects and burden of kidney disease. HRQOL is seriously affected in CKD patients. However, impairments were found irrespective of eGFR decline and albuminuria. Rather, the comorbid conditions of depression and diabetes predicted a lower HRQOL (physical component score). Further studies should address whether recognizing and treating depression may not only improve HRQOL but also promote survival and lower hospitalization rates of CKD patients.
Purpose
The continuum of mental health/illness has been subject to scientific debate for decades. While current research indicates that continuum belief interventions can reduce mental health stigma and improve treatment seeking in affected populations, no study has yet systematically examined measures of continuum beliefs.
Methods
This preregistered systematic review summarizes measures of continuum beliefs. Following the PRISMA statement, three scientific databases (PubMed, PsycInfo and PsycArticles via EBSCOhost, Web of Science) are searched, instruments are described and discussed regarding their scope, and methodological quality.
Results
Overall, 7351 records were identified, with 35 studies reporting relevant findings on 11 measures. Most studies examined general population samples and used vignette-based measures. Schizophrenia and depression were most commonly examined, few studies focused on dementia, ADHD, OCD, eating disorders, and problematic alcohol use, or compared continuum beliefs across disorders. Validity was very good for most measures, but reliability was rarely tested. Measures mostly assessed beliefs in the normality of mental health symptoms or the normality of persons with such symptoms but rarely nosological aspects (i.e., categorical v continuous conceptualization of mental disorders).
Conclusions
Current research provides psychometrically sound instruments to examine continuum beliefs for a variety of mental disorders. While studies suggest utility for general population samples and mental health professionals, more research is necessary to corroborate findings, for instance, regarding age (e.g., in adolescents), gender, or type of mental disorder. Future research should also compare self-report ratings, and vignette-based measures, include measures of nosological concepts to fully grasp the continuum concept of mental illness.
Preregistration
PROSPERO: CRD42019123606.
The fear of somatic sensations is highly relevant in the etiology and maintenance of various disorders. Nevertheless, little is known about this fear of body symptoms and many questions are yet unanswered. Especially physiological studies on interoceptive threat are rare. Therefore, the present thesis investigated defensive mobilization, autonomic arousal, and brain activation during the anticipation of, exposure to, and recovery from unpleasant body sensations. Symptoms were provoked using a standardized hyperventilation procedure in a sample of high (and as controls: low) anxiety sensitive individuals - a population high at risk for developing a panic disorder and high in fear of internal body symptoms.
In study one, anxious apprehension was investigated during anticipation of interoceptive threat (somatic sensations evoked by hyperventilation) and exteroceptive threat (electric shock). Symptom reports, autonomic arousal, and defensive mobilization assessed by the startle eyeblink response were analyzed. Extending the knowledge on anticipation of interoceptive threat, study two investigated the neural networks activated during anxious apprehension of unpleasant body sensations. Symptom reports and startle response data were collected during a learning session after which participants high and low in fear of somatic symptoms attended a fMRI session anticipating threat (hyperventilation – learned to provoke unpleasant symptoms) or safety (normal breathing). Study three examined the actual exposure to internal body symptoms, investigating symptoms reports, autonomic arousal, and the startle eyeblink response during guided breathing (hyperventilation and, as a non-provocative comparison condition, normoventilation) and during recovery. And finally, study four addressed changes in the defensive mobilization during repeated interoceptive exposure via a hyperventilation procedure. High and low anxiety sensitive persons went through two guided hyperventilation and normoventilation procedures that were spaced one week apart while symptom reports, breathing parameters, and startle response magnitudes were measured.
In study one it was demonstrated that the anticipation of exteroceptive threat led to a defensive and autonomic mobilization in high and low anxiety sensitive individuals, while during interoceptive threat only high anxiety sensitive participants were characterized by a potentiated startle response and autonomic activation. Imaging data of study two revealed that 1) during anticipation of hyperventilation all participants were characterized by an increased activation of a fear network consisting of anterior insula/ orbitofrontal cortex and rostral parts of the dorsal anterior cingulate cortex/ dorsomedial prefrontal cortex, 2) high fear individuals showed higher anxious apprehension than low fear controls during the entire context (safe and threat conditions), indexed by an overall stronger activation of the described network, and 3) while low fear controls learned that (undisclosed to all participants) in the fMRI scanner the threat cue was not followed by an unpleasant hyperventilation task, high fear participants continued to show stronger fear network activation to this cue. In study three it was demonstrated, that the hyperventilation procedure led to a marked increase in somatic symptoms and to autonomic arousal. While high and low anxiety sensitive groups did not differ during hyperventilation, in the early recovery only high anxiety sensitive individuals showed defensive mobilization, indicated by potentiated startle response magnitudes, and increased autonomic arousal after hyperventilation as compared to after normoventilation. Substantiating these findings, in study four all participants reported more symptoms during hyperventilation than during normoventilation, in both sessions. Nevertheless, only high anxiety sensitive participants displayed a potentiation of startle response magnitudes after the first hyper- vs. normoventilation. One week later, when the exercise was repeated this potentiation was no longer present and thus both groups no longer differed in their defensive mobilization. Even more, the number of reported baseline symptoms decreased from session one to session two in the high-AS group. While high anxiety sensitive persons reported increased baseline anxiety symptoms in session one, groups did not anymore differ in session two.
These data indicate that the standardized hyperventilation procedure is a valid paradigm to induce somatic symptoms. Moreover, it induces anxious apprehension especially in persons highly fearful of internal body symptoms. The repetition of interoceptive exposure, however, reduces associated fear in highly fearful individuals. Thus, this paradigm might provide an innovative method to study anxious apprehension and also treatment effects in patients with panic disorder. The present findings are integrated and discussed in the light of the current literature.
The learning theory of panic disorder differs between panic attacks and anxious apprehension as distinct emotional states. Acute panic is accompanied by extreme fear, experience of strong body symptoms reflecting autonomic surge and flight tendencies. In contrast, anxious apprehension is associated with hypervigilance towards bodily sensations and increased distress when subtle somatic symptoms are identified. Following animal models, these clinical entities reflect different stages of defensive reactivity depending upon the imminence of interoceptive or exteroceptive threat cues with lowest distance to threat during panic attacks. We tested this model by investigating the dynamics of defensive reactivity in a large group of patients suffering from panic disorder and agoraphobia (PD/AG) prior to a multicenter controlled clinical trial. Three hundred forty-five patients participated in a standardized behavioral avoidance test (being entrapped in a small, dark chamber for 10 minutes). Defensive reactivity was assessed measuring avoidance and escape behavior, self reports of anxiety and panic symptoms, autonomic arousal (heart rate and skin conductance), and potentiation of the startle reflex before and during the exposure period of the behavioral avoidance test. While 125 patients showed strong anxious apprehension during the task (as indexed by increased reports of anxiety, elevated physiological arousal, and startle potentiation), 72 patients escaped from the test chamber. Active escape was initiated at the peak of the autonomic surge accompanied by an inhibition of the startle response as predicted by the animal model. These physiological responses were observed during 34 reported panic attacks as well. We found evidence that defensive reactivity in PD/AG patients is dynamically organized ranging from anxious apprehension to panic with increasing proximity of interoceptive threat. Importantly, the patients differed quite substantially according defensive reactivity during the behavioral avoidance test despite all patients received the same principal diagnosis. These differences can be explained in part by differences in the disposition according to two genetic variants previously associated with panic disorder. Patients carrying the risk variant of a polymorphism in the neuropeptide S receptor gene showed an overall increased heart rate during the whole behavioral avoidance test reflecting an enhanced sympathomimetic activation and consequently arousal level. During the entrapment situation in which heart rate further increased over an already elevated baseline level, risk variant carriers were prone to experience more panic symptoms. This is in line with the learning perspective of panic disorder, postulating that internal cues of elevated arousal increase the chance of experiencing another panic attack once they have been associated with aversive responses. Furthermore, the risk variant of a polymorphism in the monoamine oxidase A gene was observed to augment the occurrence of panic attacks and escape behavior preparation. In addition, we find evidence that suggest an enhanced resistance to corrective learning experiences as indicated by a lack of a reduction of avoiding and escaping behavior during repeated test chamber exposures in wait-list control patients carrying the risk gene variant. Both effects may strengthen the learning mechanism hypothesized to be involved in the pathogenesis of panic disorder. Exteroceptive and interoceptive cues previously associated with the initial panic attack might trigger subsequent attacks in risk allele carriers more rapidly while simultaneously the opportunity to dissolve once established associations due to contradictory experiences is limited. Now, differential dispositions regarding defensive reactivity in PD/AG patients has to be linked to mechanisms supposed to be involved in exposure based therapy. First outcome evaluations of the clinical trial indicated that a behavioral therapy variant suggested to be linked with higher fear activation during exposure exercises is more effective than another. Further analyses have to proof whether those patients showing a clear specific fear response during the behavioral avoidance test benefit more than others from exposure based therapy.
Background: Controversy surrounds the questions whether co-occurring depression has negative effects on cognitivebehavioral therapy (CBT) outcomes in patients with panic disorder (PD) and agoraphobia (AG) and whether treatment for PD and AG (PD/AG) also reduces depressive symptomatology. Methods: Post-hoc analyses of randomized clinical trial data of 369 outpatients with primary PD/AG (DSM-IV-TR criteria) treated with a 12-session manualized CBT (n = 301) and a waitlist control group (n = 68). Patients with comorbid depression (DSM-IV-TR major depression, dysthymia, or both: 43.2% CBT, 42.7% controls) were compared to patients without depression regarding anxiety and depression outcomes (Clinical Global Impression Scale [CGI], Hamilton Anxiety Rating Scale [HAM-A], number of panic attacks, Mobility Inventory [MI], Panic and Agoraphobia Scale, Beck Depression Inventory) at post-treatment and follow-up (categorical). Further, the role of severity of depressive symptoms on anxiety/depression outcome measures was examined (dimensional). Results: Comorbid depression did not have a significant overall effect on anxiety outcomes at post-treatment and follow-up, except for slightly diminished post-treatment effect sizes for clinician-rated CGI (p = 0.03) and HAM-A (p = 0.008) when adjusting for baseline anxiety severity. In the dimensional model, higher baseline depression scores were associated with lower effect sizes at post-treatment (except for MI), but not at follow-up (except for HAM-A). Depressive symptoms improved irrespective of the presence of depression. Conclusions: Exposure-based CBT for primary PD/AG effectively reduces anxiety and depressive symptoms, irrespective of comorbid depression or depressive symptomatology.
Development of the Greifswald questionnaire for the measurement of interprofessional attitudes
(2020)
Two decades of research indicate that visual processing is typically enhanced for items that are in the space near the hands (near-hand space). Enhanced attention and cognitive control have been thought to be responsible for the observed effects, amongst others. As accumulating experimental evidence and recent theories of dual-tasking suggest an involvement of cognitive control and attentional processes during dual tasking, dual-task performance may be modulated in the near-hand space. Therefore, we performed a series of three experiments that aimed to test if the near-hand space affects the shift between task-component processing in two visual-manual tasks. We applied a Psychological Refractory Period Paradigm (PRP) with varying stimulus-onset asynchrony (SOA) and manipulated stimulus-hand proximity by placing hands either on the side of a computer screen (near-hand condition) or on the lap (far-hand condition). In Experiment 1, Task 1 was a number categorization task (odd vs. even) and Task 2 was a letter categorization task (vowel vs. consonant). Stimulus presentation was spatially segregated with Stimulus 1 presented on the right side of the screen, appearing first and then Stimulus 2, presented on the left side of the screen, appearing second. In Experiment 2, we replaced Task 2 with a color categorization task (orange vs. blue). In Experiment 3, Stimulus 1 and Stimulus 2 were centrally presented as a single bivalent stimulus. The classic PRP effect was shown in all three experiments, with Task 2 performance declining at short SOA while Task 1 performance being relatively unaffected by task-overlap. In none of the three experiments did stimulus-hand proximity affect the size of the PRP effect. Our results indicate that the switching operation between two tasks in the PRP paradigm is neither optimized nor disturbed by being processed in near-hand space.
Background
Numerous wearables are used in a research context to record cardiac activity although their validity and usability has not been fully investigated. The objectives of this study is the cross-model comparison of data quality at different realistic use cases (cognitive and physical tasks). The recording quality is expressed by the ability to accurately detect the QRS complex, the amount of noise in the data, and the quality of RR intervals.
Methods
Five ECG devices (eMotion Faros 360°, Hexoskin Hx1, NeXus-10 MKII, Polar RS800 Multi and SOMNOtouch NIBP) were attached and simultaneously tested in 13 participants. Used test conditions included: measurements during rest, treadmill walking/running, and a cognitive 2-back task. Signal quality was assessed by a new local morphological quality parameter morphSQ which is defined as a weighted peak noise-to-signal ratio on percentage scale. The QRS detection performance was evaluated with eplimited on synchronized data by comparison to ground truth annotations. A modification of the Smith-Waterman algorithm has been used to assess the RR interval quality and to classify incorrect beat annotations. Evaluation metrics includes the positive predictive value, false negative rates, and F1 scores for beat detection performance.
Results
All used devices achieved sufficient signal quality in non-movement conditions. Over all experimental phases, insufficient quality expressed by morphSQ values below 10% was only found in 1.22% of the recorded beats using eMotion Faros 360°whereas the rate was 8.67% with Hexoskin Hx1. Nevertheless, QRS detection performed well across all used devices with positive predictive values between 0.985 and 1.000. False negative rates are ranging between 0.003 and 0.017. eMotion Faros 360°achieved the most stable results among the tested devices with only 5 false positive and 19 misplaced beats across all recordings identified by the Smith-Waterman approach.
Conclusion
Data quality was assessed by two new approaches: analyzing the noise-to-signal ratio using morphSQ, and RR interval quality using Smith-Waterman. Both methods deliver comparable results. However the Smith-Waterman approach allows the direct comparison of RR intervals without the need for signal synchronization whereas morphSQ can be computed locally.