Few negative effects of psychotherapy in a psychiatric day hospital: a follow-up survey to a multiprofessional treatment with acceptance and commitment therapy.

While there are many studies on psychotherapy and its efficacy - in terms of desired outcomes - there is comparatively little evidence on the possible negative effects of psychotherapy. The aim of this study was to investigate the possible negative effects of a multi-professional psychiatric day hospital treatment for patients with mental health disorders based on Acceptance and Commitment Therapy (ACT), including possible confounding factors. Fifty-one patients with a range of psychiatric diagnoses were assessed three months after an ACT-based psychiatric day hospital treatment. Questionnaires were used to measure negative effects of psychotherapy (INEP), subjective quality of life (WHOQOL-BREF), and symptomatology (BDI-II and SCL-90-R). Correlational analyses and group comparisons were performed to determine the relationship between the sum of reported negative effects on the one hand and symptomology, quality of life, and sociodemographic variables (gender, age, diagnosis, education) on the other hand. At least one negative effect out of a list of 18 possible effects was reported by 45% of participants, and 10% reported more than two. The number of negative effects reported correlates positively with symptomology and negatively with quality of life. The sum of reported negative effects does not correlate with age or gender and does not vary by education level and primary diagnosis. In the light of previous findings, patients included in this study showed lower rates of negative effects, both overall and at item level. Practical implications of these findings are discussed.

DR.BEAT: Initial Functional Testing of a BCG Wearable Prototype for Recording Ballistocardiographic Signals.

DR.BEAT ("Digital Research on Ballistocardiography for Extraterrestrial And Terrestrial use") develops a miniaturized sensor system with signal processing to interpret ballistocardiographic signals and implements an application oriented user interface. Presented is a breadboard prototype's functional tests with regard to data completeness and plausibility. The analysis confirmed a reliability of 99.99995% over the tests and the signals displayed the expected heart-specific characteristics. These results support the ethical justifiability of an initial study.

DR.BEAT: First Insights into a Study to Collect Baseline BCG Data with a Sensor-Based Wearable Prototype in Heart-Healthy Adults.

The DR.BEAT project aims at the further development of a measurement system for recording ballistocardiographic signals into a body-worn sensor system combined with extensive signal processing, data evaluation and visualization. With a first breadboard prototype, an explorative feasibility study for acquiring initial signals of healthy cardiac activity in adults was performed. This paper briefly presents the DR.BEAT project, the breadboard prototype, the study conducted, and initial insights into the study results. The signals obtained in the study exhibit the seismocardiographic characteristics as reported in the literature and form the basis for further development of the hardware as well as the pre-processing and automated analysis algorithms in the DR.BEAT project.Clinical Relevance- The characteristics of ballisto- and seismocardiographic signals allow to infer about the mechanical work of the heart. The development of a body-worn sensor system to record ballisto- and seismocardiographic signals, compact enough for everyday wear, enables the acquisition of heart-specific parameters in terrestrial as well as extraterrestrial application scenarios. Combined with extensive signal analysis and visualization, it holds the potential to monitor heart health in a variety of contexts and support its maintenance and improvement.

Acute effects of lithium augmentation on the kidney in geriatric compared with non-geriatric patients with treatment-resistant depression.

INTRODUCTION: Lithium augmentation (LA) of antidepressants is a first-line therapy option for treatment-resistant depression (TRD). Nevertheless, it is rarely used in geriatric patients mostly because of the fear of kidney toxicity. The purpose of this study is to investigate estimated glomerular filtration rate (eGFR) changes and number of acute kidney injuries (AKI) using LA in geriatric compared with non-geriatric patients. METHODS: In a prospective multicenter cohort study, eGFR changes were measured in 201 patients with unipolar depression (nage≥65years  = 29; nage<65years  = 172) at baseline and over 2-6 weeks of LA. We used linear mixed models to investigate changes in eGFR upon LA and assessed the number of AKIs, according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. RESULTS: Both age groups showed a significant eGFR decline over the course of treatment with lower eGFR in geriatric patients. The lithium serum level (interpretable as "effect of LA") had a significant effect on eGFR decline. Both effects (age group and lithium serum level) on eGFR decline did not influence each other, meaning the effect of LA on eGFR decline did not differ between age groups. Two AKIs were observed in the geriatric age group when serum lithium levels exceeded the therapeutic range of >0.8 mmol/L. CONCLUSION: This is the first study investigating eGFR change and AKI upon LA for TRD in geriatric compared with non-geriatric patients. Our data suggest that LA, as an effective treatment option in geriatric patients, should be closely monitored to avoid AKIs.

Effect of Colorants and Process Parameters on the Properties of Dope-Dyed Polylactic Acid Multifilament Yarns.

The color of textile fibers is typically imparted by submersion in a high-temperature dye bath. However, the treatment of the effluent is challenging and the textile industry is therefore a major source of water pollution. Current fashion trends favor biobased polymers such as polylactic acid (PLA) but exhaust dyeing at high temperatures causes hydrolytic degradation, reducing the crystallinity and tenacity of the yarn. To preserve the mechanical properties of PLA-based textiles, an alternative to exhaust dyeing called dope dyeing can be used, wherein colorants are incorporated into the polymer matrix during melt spinning. We evaluated this process by dope dyeing PLA with several colorants, then testing the thermal, physical, and mechanical properties of the yarn and the physical properties of circular-knitted fabrics. Although the colorants affected the crystallization behavior at lower cooling rates, during the melt-spinning process, the drawing speed had a greater effect on the crystallinity and mechanical properties of the dyed yarn. Scanning electron microscopy revealed that the colorants were well dispersed in the PLA matrix. We found that the colorants did not affect the physical properties of the knitted fabric. Our results can be used to develop more environmentally beneficial dope-dyed PLA yarn with improved mechanical properties.

Electrocardiographic Changes During Initiation of Lithium Augmentation of Antidepressant Pharmacotherapy.

PURPOSE/BACKGROUND: Lithium augmentation of antidepressants represents a common strategy to overcome treatment resistance in patients with major depressive disorder. The use of lithium has been associated with cardiovascular adverse effects such as QTc prolongation and tachyarrhythmia. Although the previous studies investigated monotherapy with lithium, the aim of this study was to investigate electrocardiographic changes in LA. METHODS/PROCEDURES: A 12-lead surface electrocardiogram (ECG) was obtained from 38 patients with major depressive disorder before and during LA. Changes in heart rate, PQ, QRS and QTc interval, QT dispersion, ST segment, and T- and U-wave alterations were analyzed using a linear mixed model. FINDINGS/RESULTS: The ECG readings of 33 patients were evaluated. Lithium augmentation was not significantly associated with changes in heart rate, QTc, PQ, or QRS interval. We found a significant decrease in QT dispersion. These results were independent of sex, age, stable comedication, and comorbidities. During LA, we observed 9 cases of T-wave alterations and 2 cases of new U waves. CONCLUSIONS: Our data provide no evidence for serious ECG abnormalities at therapeutic serum lithium levels in patients treated with LA. In particular, we did not find evidence for QTc time lengthening or tachyarrhythmia, such as torsades des pointes. The recommended intervals for ECG checks should be considered to detect long-term effects of LA.

Acceptance and commitment therapy in a psychiatric day hospital-A longitudinal naturalistic effectiveness trial.

Objectives: Despite the transdiagnostic approach and the good cross-professional applicability, only few studies have examined the effects of Acceptance and Commitment Therapy (ACT) in a naturalistic clinic setting. This study aims to help closing this gap by investigating the effects of ACT in a psychiatric day hospital during COVID pandemic. It was investigated whether psychopathological symptomology decreased, and quality of life and general functioning improved with the treatment. Additionally, longitudinal effects were tested. Methods: Participants in this follow-up-design were 92 patients (64.1% female) of a psychiatric day hospital. Survey data of clinical symptoms, quality of life and global functioning were assessed at three time points (with admission, discharge, and 3 months after treatment). Differences between time points were tested using two-sided paired samples t-tests. Additionally, the reliability of change index (RCI) was calculated. Results: From pre-treatment to post-treatment, symptomology decreased significantly (d = 0.82-0.99, p < 0.001), and global functioning as well as quality of life increased significantly (d = 0.42-1.19, p < 0.001). The effects remained relatively stable, with no significant change between post-treatment and follow-up. The difference between pre-treatment and follow-up was significant for clinical symptoms, physical and psychological wellbeing, and global quality of life (d = 0.43-0.76, p < 0.007). Conclusion: The significant and sustained improvement in all measures indicates that patients are benefiting from the treatment. Since the trial was neither randomized nor controlled, effects have to be interpreted with caution. Possible influences of the pandemic are discussed. Clinical trial registration: http://www.drks.de/DRKS00029992, identifier DRKS00029992.

Faster speed of onset of the depressive episode is associated with lower cytokine serum levels (IL-2, -4, -6, -10, TNF-α and IFN-γ) in patients with major depression.

INTRODUCTION: Cytokines might play a key role in the pathophysiology of major depressive disorder (MDD). The speed of onset of depressive episodes has been discussed as an important clinical parameter in MDD. The aim of this study was to investigate a potential influence of the speed of onset of the depressive episode on cytokine serum levels. METHOD: Serum level of the cytokines interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ) granulocyte and monocyte colony stimulating factor (GM-CSF) were measured in a total of 92 patients with MDD that did not respond to at least one previous antidepressant treatment. Patients were retrospectively divided in two groups: Faster (≤4 weeks) and slower (>4 weeks) onset of the depressive episode defined as the time passing from the first depressive symptoms to a full-blown depressive episode by using information from a clinical interview. RESULTS: We found significantly lower serum levels of IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ in patients with a faster onset compared to patients with a slower onset of the depressive episodes. Furthermore, lower cytokine serum levels of IL-2, IL-8, IL-10 and IFN-γ were found in patients with a shorter duration (less than 6 months) compared to a longer duration (6-24 months) of the current depressive episode. This effect on cytokines was independent from the effect of the speed of onset of the depressive episode. CONCLUSIONS: Patients with faster onset of the depressive episode might represent a biological subtype of MDD with lower serum levels of IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ.

Online but not remote: Adapting field-based ecology laboratories for online learning.

Teaching ecology effectively and experientially has become more challenging for at least two reasons today. Most experiences of our students are urban, and we now face the near immediate and continuing need to deliver courses (either partially or wholly) online because of COVID-19. Therefore, providing a learning experience that connects students to their environment within an ecological framework remains crucial and perhaps therapeutic to mental health. Here, we describe how prior to the pandemic we adapted our field-based laboratories to include data collection, analysis, and interpretation, along with the development of a citizen-science approach for online delivery. This design is simple to implement, does not require extensive work, and maintains the veracity of original learning outcomes. Collaboration online following field data collection in ecology courses within the context of cities offers further options to adapt to student experience levels, resource availability, and accessibility, as well as bringing instructors and students together to build an open well-curated data set that can be used in ecology courses where no laboratories are available. Finally, it promotes an open collaboration among ecology instructors that can drive lasting conversations about ecology curriculum.

Development of screening questions for doctor-patient consultation assessing the quality of life and psychosocial burden of glioma patients: an explorative study.

PURPOSE: Psychosocial screening for glioma patients is challenging because many patients suffer from neurocognitive deficits, which may impair assessment. This study's aim was to exploratively develop three screening questions for unmet needs to prospectively be applicable in patient-doctor consultation. METHODS: Patient interviews, a survey for health-care professionals and a weighted scoring procedure were developed for this study. Six main areas were defined according to main areas of validated questionnaires (psyche, cognition, body, role functioning, social support, unmet needs). Patients and health-care professionals rated the importance of these areas and corresponding items, patients additionally stated whether the issues addressed affected them. RESULTS: A total of 50 patients were included, and 36 health-care professionals participated in the online survey. The three areas (psyche, body and cognition) considered to be most relevant by both, health-care professionals and patients, generated three screening questions. If the patient was affected by the issue addressed with a screening question, a subordinate question from that area that our patient sample considered most important could additionally be asked. The elaborated screening questions are the following: (1) main area psyche: "Has your mood worsened?", (2) main area body: "Do physical changes put a strain on you?", and (3) main area cognition: "Has your memory capacity worsened?" CONCLUSION: These questions represent a basis for further research regarding their application in neuro-oncological clinical routine.

["I Indeed Consider it to be a Temporary Solution" - A Qualitative Analysis of the Conditions and Obstacles to Implementation of Psychiatric Home-Treatment in Berlin and Brandenburg]. / "Ich sehe es tatsächlich als Zwischenschritt" ­ eine qualitative Analyse der Implementierungsbedingungen und -hürden von Stationsäquivalenter Behandlung in Berlin und Brandenburg.

OBJECTIVE: The obstacles to implementation of a German variation of psychiatric Home-Treatment (HT), called "Inpatient Equivalent Home-Treatment" (IEHT) are examined. METHOD: 43 employees from 11 psychiatric hospitals in the federal states of Berlin and Brandenburg were questioned using interviews and focus groups. A thematic analysis was conducted using the socio-institutional theoretical model. RESULTS: At system-level, implementation is hampered by an inadequate service definition, staff shortages, as well as performance assessments by health insurances. This leads to reluctant implementation at hospital-level with insufficient staffing of the teams. Other barriers include a lack of mobile devices for documentation and team communication. At the level of employees, poor information, and cooperation as well as unclear assignment of tasks are impeding factors. CONCLUSION: For a more needs-oriented, flexible, and nationwide introduction of HT according to IEHT, improvements to the underlying framework conditions and further research addressing efficacy, effectiveness and implementation are necessary.

Intuitive Judgments in Depression and the Role of Processing Fluency and Positive Valence: A Preregistered Replication Study.

Background: Recent preliminary evidence indicates that depression is associated with impaired intuitive information processing. The current study aimed at replicating these findings and to move one step further by exploring whether factors known as triggering intuition (positivity, processing fluency) also affect intuition in patients with depression. Method: We pre-registered and tested five hypotheses using data from 35 patients with depression and 35 healthy controls who performed three versions of the Judgment of Semantic Coherence Task (JSCT, Bowers et al., 1990). This task operationalizes intuition as the inexplicable and sudden detection of semantic coherence. Results: Results revealed that depressed patients and healthy controls did not differ in their general intuitive performance (Hypothesis 1). We further found that fluency did not significantly affect depressed patients' coherence judgments (H2a) and that the assumed effect of fluency on coherence judgments was not moderated by depression (H2b). Finally, we found that triads positive in valence were more likely to be judged as coherent as compared to negative word triads in the depressed sample (H3a), but this influence of positive (vs. negative) valence on coherence judgments did not significantly differ between the two groups (H3b). Conclusion: Overall the current study did not replicate findings from previous research regarding intuitive semantic coherence detection deficits in depression. However, our findings suggest that enhancing positivity in depressed patients may facilitate their ability to see meaning in their environment and to take intuitive decision.

Treatment response of lithium augmentation in geriatric compared to non-geriatric patients with treatment-resistant depression.

BACKGROUND: Lithium augmentation (LA) of antidepressants is an effective strategy for treatment-resistant depression (TRD). Nevertheless, it is rarely used in geriatric patients. The purpose of this study was to investigate treatment response of LA in geriatric compared to non-geriatric patients. METHOD: In a prospective multicenter cohort study, severity of depression was measured weekly in 167 patients with unipolar depression (nage≥65years = 22; nage<65years = 145) at baseline and over at least four weeks of LA. RESULTS: Geriatric patients showed a significantly better response to LA compared to non-geriatric patients (Hazard Ratio = 1.91; p = 0.04). LIMITATIONS: An important limitation of our study is the lack of a control group of LA and the missing evaluation of side effects in both groups. CONCLUSIONS: This is the first study investigating the efficacy of LA for TRD in geriatric compared to non-geriatric patients. Our data suggest that LA is an effective treatment option in geriatric patients that clinicians might consider more frequently and earlier on in the course of treatment.

Validating Deep Neural Networks for Online Decoding of Motor Imagery Movements from EEG Signals.

Non-invasive, electroencephalography (EEG)-based brain-computer interfaces (BCIs) on motor imagery movements translate the subject's motor intention into control signals through classifying the EEG patterns caused by different imagination tasks, e.g., hand movements. This type of BCI has been widely studied and used as an alternative mode of communication and environmental control for disabled patients, such as those suffering from a brainstem stroke or a spinal cord injury (SCI). Notwithstanding the success of traditional machine learning methods in classifying EEG signals, these methods still rely on hand-crafted features. The extraction of such features is a difficult task due to the high non-stationarity of EEG signals, which is a major cause by the stagnating progress in classification performance. Remarkable advances in deep learning methods allow end-to-end learning without any feature engineering, which could benefit BCI motor imagery applications. We developed three deep learning models: (1) A long short-term memory (LSTM); (2) a spectrogram-based convolutional neural network model (CNN); and (3) a recurrent convolutional neural network (RCNN), for decoding motor imagery movements directly from raw EEG signals without (any manual) feature engineering. Results were evaluated on our own publicly available, EEG data collected from 20 subjects and on an existing dataset known as 2b EEG dataset from "BCI Competition IV". Overall, better classification performance was achieved with deep learning models compared to state-of-the art machine learning techniques, which could chart a route ahead for developing new robust techniques for EEG signal decoding. We underpin this point by demonstrating the successful real-time control of a robotic arm using our CNN based BCI.

Classification and regression of spatio-temporal signals using NeuCube and its realization on SpiNNaker neuromorphic hardware.

OBJECTIVE: The objective of this work is to use the capability of spiking neural networks to capture the spatio-temporal information encoded in time-series signals and decode them without the use of hand-crafted features and vector-based learning and the realization of the spiking model on low-power neuromorphic hardware. APPROACH: The NeuCube spiking model was used to classify different grasp movements directly from raw surface electromyography signals (sEMG), the estimations of the applied finger forces as well as the classification of two motor imagery movements from raw electroencephalography (EEG). In a parallel investigation, the designed spiking decoder was implemented on SpiNNaker neuromorphic hardware, which allows low-energy real-time processing. MAIN RESULTS: Experimental results reveal a better classification accuracy using the NeuCube model compared to traditional machine learning methods. For sEMG classification, we reached a training accuracy of 85% and a test accuracy of 84.8%, as well as less than 19% of relative root mean square error (rRMSE) when estimating finger forces from six subjects. For the EEG classification, a mean accuracy of 75% was obtained when tested on raw EEG data from nine subjects from the existing 2b dataset from 'BCI competition IV'. SIGNIFICANCE: This work provides a proof of concept for a successful implementation of the NeuCube spiking model on the SpiNNaker neuromorphic platform for raw sEMG and EEG decoding, which could chart a route ahead for a new generation of portable closed-loop and low-power neuroprostheses.

Leptin gene polymorphisms are associated with weight gain during lithium augmentation in patients with major depression.

Weight gain is a common adverse effect of lithium augmentation. Previous studies indicate an impact of genetic variants at the leptin gene on weight gain as a consequence of psychopharmacological treatment. The primary aim of our study was to identify variants at the leptin locus that might predict lithium-induced weight gain. The secondary aim was to investigate if these variants modulate leptin levels. In 180 patients with acute major depressive disorder, body mass index was measured before and after 4 weeks of lithium augmentation, in a subsample also after 4 and/or 7 months. In a subsample of 89 patients, leptin serum concentrations were measured before and during lithium augmentation. We used linear mixed model analyzes to investigate the effects of 2 polymorphisms at the leptin locus (rs4731426 and rs7799039, employing the respective proxy SNPs rs2278815 and rs10487506) on changes in body mass index and leptin levels. For both polymorphisms, which are in high linkage disequilibrium, body mass index was significantly lower in homozygous A-allele carriers than in carriers of other genotypes at baseline. Over the follow-up period, body mass index increased less in homozygous A-allele carriers of rs4731426 than in carriers of other genotypes. This was not the case for rs7799039. Neither polymorphism modulated leptin protein expression. Our study strongly supports the hypothesis that genetic variability at the leptin locus is involved in lithium augmentation-associated weight gain in major depressive disorder. Furthermore, Genotype-Tissue Expression data provide strong evidence that rs4731426 influences the expression of leptin messenger ribonucleic acid in fibroblasts.

Gumpy: a Python toolbox suitable for hybrid brain-computer interfaces.

OBJECTIVE: The objective of this work is to present gumpy, a new free and open source Python toolbox designed for hybrid brain-computer interface (BCI). APPROACH: Gumpy provides state-of-the-art algorithms and includes a rich selection of signal processing methods that have been employed by the BCI community over the last 20 years. In addition, a wide range of classification methods that span from classical machine learning algorithms to deep neural network models are provided. Gumpy can be used for both EEG and EMG biosignal analysis, visualization, real-time streaming and decoding. RESULTS: The usage of the toolbox was demonstrated through two different offline example studies, namely movement prediction from EEG motor imagery, and the decoding of natural grasp movements with the applied finger forces from surface EMG (sEMG) signals. Additionally, gumpy was used for real-time control of a robot arm using steady-state visually evoked potentials (SSVEP) as well as for real-time prosthetic hand control using sEMG. Overall, obtained results with the gumpy toolbox are comparable or better than previously reported results on the same datasets. SIGNIFICANCE: Gumpy is a free and open source software, which allows end-users to perform online hybrid BCIs and provides different techniques for processing and decoding of EEG and EMG signals. More importantly, the achieved results reveal that gumpy's deep learning toolbox can match or outperform the state-of-the-art in terms of accuracy. This can therefore enable BCI researchers to develop more robust decoding algorithms using novel techniques and hence chart a route ahead for new BCI improvements.

Cytokine serum levels remain unchanged during lithium augmentation of antidepressants in major depression.

Lithium augmentation (LA) of antidepressants is a first-line therapy in treatment-resistant depression. Immunomodulatory effects of lithium have been described. The cytokine hypothesis of depression postulates that cytokines play a key role in the pathophysiology of depression. Concordantly, it has been shown that proinflammatory cytokine serum levels decrease during antidepressant treatment. The aim of this study was to investigate changes in cytokine serum levels during LA. Serum concentrations of the cytokines interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor alpha, interferon-gamma, granulocyte and monocyte colony stimulating factor were measured in a total of 95 acutely depressed patients before and after four weeks of LA. Changes in cytokine levels were corrected for the confounding factors severity of depression, treatment response, lithium serum level, gender, age and body mass index in a linear mixed-model analysis. We did not find a significant change in any of the measured cytokine serum levels during LA (p > 0.05). In conclusion, our study does not support the role of cytokine serum levels as a state marker in treatment of depression with LA.

Ghrelin Serum Concentrations Are Associated with Treatment Response During Lithium Augmentation of Antidepressants.

Background: Lithium augmentation of antidepressants is an effective strategy in treatment-resistant depression. The proteohormone ghrelin is thought to be involved in the pathophysiology of depression. The purpose of this study was to investigate the association of treatment response with the course of ghrelin levels during lithium augmentation. Method: Ghrelin serum concentrations and severity of depression were measured in 85 acute depressive patients before and after 4 weeks of lithium augmentation. Results: In a linear mixed model analysis, we found a significant effect of response*time interaction (F1.81=9.48; P=.0028): under treatment, ghrelin levels increased in nonresponders and slightly decreased in responders to lithium augmentation. The covariate female gender had a significant positive effect (F1.83=4.69; P=.033), whereas time, response, appetite, and body mass index (kg/m2) did not show any significant effect on ghrelin levels (P>.05). Conclusion: This is the first study showing that the course of ghrelin levels separates responders and nonresponders to lithium augmentation. Present results support the hypothesis that ghrelin serum concentrations might be involved in response to pharmacological treatment of depression.

A Self-Synthesis Approach to Perceptual Learning for Multisensory Fusion in Robotics.

Biological and technical systems operate in a rich multimodal environment. Due to the diversity of incoming sensory streams a system perceives and the variety of motor capabilities a system exhibits there is no single representation and no singular unambiguous interpretation of such a complex scene. In this work we propose a novel sensory processing architecture, inspired by the distributed macro-architecture of the mammalian cortex. The underlying computation is performed by a network of computational maps, each representing a different sensory quantity. All the different sensory streams enter the system through multiple parallel channels. The system autonomously associates and combines them into a coherent representation, given incoming observations. These processes are adaptive and involve learning. The proposed framework introduces mechanisms for self-creation and learning of the functional relations between the computational maps, encoding sensorimotor streams, directly from the data. Its intrinsic scalability, parallelisation, and automatic adaptation to unforeseen sensory perturbations make our approach a promising candidate for robust multisensory fusion in robotic systems. We demonstrate this by applying our model to a 3D motion estimation on a quadrotor.