The relationship between self-reported physical frailty and sensor-based physical activity measures in older adults - a multicentric cross-sectional study

BACKGROUND

The decline in everyday life physical activity reflects and contributes to the frailty syndrome. While especially self-reported frailty assessments have the advantage of reaching large groups at low costs, little is known about the relationship between the self-report and objective measured daily physical activity behavior. The main objective was to evaluate whether and to what extent a self-reported assessment of frailty is associated with daily physical activity patterns.

METHODS

Daily activity data were obtained from 88 elderly participants (mean 80.6 ± 9.1 years) over up to 21 days. Acceleration data were collected via smartwatch. According to the results of a self-report frailty questionnaire, participants were retrospectively split up into three groups, F (frail, n = 43), P (pre-frail, n = 33), and R (robust, n = 12). Gait- and activity-related measures were derived from the built-in step detector and acceleration sensor and comprised, i.a., standard deviation of 5-s-mean amplitude deviation (MADstd), median MAD (MADmedian), and the 95th percentile of cadence (STEP95). Parameters were fed into a PCA and component scores were used to derive behavioral clusters.

RESULTS

The PCA suggested two components, one describing gait and one upper limb activity. Mainly gait related parameters showed meaningful associations with the self-reported frailty score (STEP95: R² = 0.25), while measures of upper limb activity had lower coefficients (MADmedian: R² = 0.07). Cluster analysis revealed two clusters with low and relatively high activity in both dimensions (cluster 2 and 3). Interestingly, a third cluster (cluster 1) was characterized by high activity and low extent of ambulation. Comparisons between the clusters showed significant differences between activity, gait, age, sex, number of chronic diseases, health status, and walking aid. Particularly, cluster 1 contained a higher number of female participants, whose self-reports tended towards a low health status, the frequent use of a walking aid, and a higher score related to frailty questions.

CONCLUSIONS

The results demonstrate that subjective frailty assessments may be a simple first screening approach. However, especially older women using walking aids may classify themselves as frail despite still being active. Therefore, the results of self-reports may be particularly biased in older women.

P0664CKDSENS, A NOVEL HEALTHCARE PLATFORM FOR CHRONIC KIDNEY DISEASE

Background and Aims

The 10% of the global adult population, more than 730 million people, suffers from some degree of chronic kidney disease (CKD). From that population, a 30% is suffering from an advanced stage of the disease. Approximately 38 million of the European population is affected by an advanced stage renal disease with 1 million of new cases every year. These patients require close monitoring, which increase the burden of the disease. New tools and methods are required to improve the patients’ well-being, the perception and management of their disease, decrease the impact of the complications, as well as to delay of the progression of the disease.

Method

Seven partners have joined in the CKDSens consortium and are contributing to the project with different expertise and technical resources (medical, technological, educational, business and management): CreatSens Health SL, Hospital Clínic de Barcelona – Fundació Privada Clínic per a la Recerca Biomèdica, Genesis Biomed, Eurecat, Universitat de Barcelona, Universidad Politécnica de Madrid, and Madopa. This consortium is a novel and unique technological platform, combining in vitro diagnostic devices and software components, that connects patients with CKD and healthcare professionals to improve the well-being of people and the efficiency of the healthcare system by monitoring relevant biomarkers out of the hospital in a simple and cost- effective connected paper-based sensors. The proposal aims to increase the quality of life of CKD patients through early diagnostics, real time monitoring and personalization of therapies.

Results

The CKDSens consortium is developing a novel technological platform for real-time and low-cost diagnostics for two key biomarkers in renal diseases (creatinine and potassium), which include a new point-of-care device that allows monitoring by remote control these biomarkers. The technology has been patented for both biomarkers, and it has been transferred to CreatSens, a spinoff from Universitat Rovira i Virgili. The product integrates paper-based sensors in a drop of blood analysis, wireless connectivity and a digital platform as data analytics. The aim of the consortium is to validate the use of a new medical device as a product that can fit and truly generate value and business. Through that perspective, the optimization, manufacturing and validation of the tool and the business case will be performed as a first step, while usability, end user interaction and regulatory pathway will be developed in the second step. CKDSens will afford a novel approach to embed healthcare in daily life and routine. This new strategy implies production and commercialization for prevention and diagnose where markets are well known and validated. The aim is to mimic a well-known business model such as glucometer, translating this one into renal diseases. CKDSens has risen funding for this purpose through a grant of the European Institute of Innovation and Technology (EIT Health, ID Project 19579), and it is working to have validated this device at the end of the year. This requires also a clinical validation, which will be performed in a clinical trial in the second half of the year.

Conclusion

CKDSens consortium has been created as a novel technological platform to develop and validate a new medical device for a remote control of patients with CKD, in order to increase the quality of life of CKD patients through early diagnostics, real time monitoring and personalization of therapies. It is expected to have this device designed and validated by the end of the year 2020 and ready for further commercialization.

Big-Loop Recurrence within the Hippocampal System Supports Integration of Information across Episodes

Recent evidence challenges the widely held view that the hippocampus is specialized for episodic memory, by demonstrating that it also underpins the integration of information across experiences. Contemporary computational theories propose that these two contrasting functions can be accomplished by big-loop recurrence, whereby the output of the system is recirculated back into the hippocampus. We use ultra-high-resolution fMRI to provide support for this hypothesis, by showing that retrieved information is presented as a new input on the superficial entorhinal cortex-driven by functional connectivity between the deep and superficial entorhinal layers. Further, the magnitude of this laminar connectivity correlated with inferential performance, demonstrating its importance for behavior. Our findings offer a novel perspective on information processing within the hippocampus and support a unifying framework in which the hippocampus captures higher-order structure across experiences, by creating a dynamic memory space from separate episodic codes for individual experiences.

The Neural Representation of Prospective Choice during Spatial Planning and Decisions

We are remarkably adept at inferring the consequences of our actions, yet the neuronal mechanisms that allow us to plan a sequence of novel choices remain unclear. We used functional magnetic resonance imaging (fMRI) to investigate how the human brain plans the shortest path to a goal in novel mazes with one (shallow maze) or two (deep maze) choice points. We observed two distinct anterior prefrontal responses to demanding choices at the second choice point: one in rostrodorsal medial prefrontal cortex (rd-mPFC)/superior frontal gyrus (SFG) that was also sensitive to (deactivated by) demanding initial choices and another in lateral frontopolar cortex (lFPC), which was only engaged by demanding choices at the second choice point. Furthermore, we identified hippocampal responses during planning that correlated with subsequent choice accuracy and response time, particularly in mazes affording sequential choices. Psychophysiological interaction (PPI) analyses showed that coupling between the hippocampus and rd-mPFC increases during sequential (deep versus shallow) planning and is higher before correct versus incorrect choices. In short, using a naturalistic spatial planning paradigm, we reveal how the human brain represents sequential choices during planning without extensive training. Our data highlight a network centred on the cortical midline and hippocampus that allows us to make prospective choices while maintaining initial choices during planning in novel environments.

Using neuroimaging and computational modelling, this study explains how the human brain represents initial versus subsequent choices during spatial planning in novel environments.

We are remarkably adept at inferring the consequences of our actions, even in novel situations. However, the neuronal mechanisms that allow us to plan a sequence of novel choices remain a mystery. One hypothesis is that anterior prefrontal brain regions can jump ahead from an initial decision to evaluate subsequent choices. Here, we examine how the brain represents initial versus subsequent choices of varying difficulty during spatial planning in novel environments. Specifically, participants visually searched for the shortest path to a goal in pictures of novel mazes that contained one or two path junctions. We monitored the participants’ brain activity during the task with functional magnetic resonance imaging (fMRI). We observed, in the anterior prefrontal brain, two distinct responses to demanding choices at the second junction: one in the rostrodorsal medial prefrontal cortex (rd-mPFC), which also signalled less demanding initial choices, and another one in the lateral frontopolar cortex (lFPC), which was only engaged by demanding choices at the second junction. Notably, interactions of the rd-mPFC with the hippocampus, a region associated with memory, increased when planning required extensive deliberation and particularly when planning led to accurate choices. Our findings show how humans can rapidly formulate a plan in novel environments. More broadly, these data uncover potential neural mechanisms underlying how we make inferences about states beyond a current subjective state.

Retrieval-Based Model Accounts for Striking Profile of Episodic Memory and Generalization

A fundamental theoretical tension exists between the role of the hippocampus in generalizing across a set of related episodes, and in supporting memory for individual episodes. Whilst the former requires an appreciation of the commonalities across episodes, the latter emphasizes the representation of the specifics of individual experiences. We developed a novel version of the hippocampal-dependent paired associate inference (PAI) paradigm, which afforded us the unique opportunity to investigate the relationship between episodic memory and generalization in parallel. Across four experiments, we provide surprising evidence that the overlap between object pairs in the PAI paradigm results in a marked loss of episodic memory. Critically, however, we demonstrate that superior generalization ability was associated with stronger episodic memory. Through computational simulations we show that this striking profile of behavioral findings is best accounted for by a mechanism by which generalization occurs at the point of retrieval, through the recombination of related episodes on the fly. Taken together, our study offers new insights into the intricate relationship between episodic memory and generalization, and constrains theories of the mechanisms by which the hippocampus supports generalization.

Stimulus Novelty Energizes Actions in the Absence of Explicit Reward

Novelty seeking has been tied to impulsive choice and biased value based choice. It has been postulated that novel stimuli should trigger more vigorous approach and exploration. However, it is unclear whether stimulus novelty can enhance simple motor actions in the absence of explicit reward, a necessary condition for energizing approach and exploration in an entirely unfamiliar situation. In this study human subjects were cued to omit or perform actions in form of button presses by novel or familiar images. We found that subjects’ motor actions were faster when cued by a novel compared to a familiar image. This facilitation by novelty was strongest when the delay between cue and action was short, consistent with a link between novelty and impulsive choices. The facilitation of reaction times by novelty was correlated across subjects with trait novelty seeking as measured in the Tridimensional Personality Questionnaire. However, this li between high novelty-seeking and action facilitation was driven by trials with a long delay between cue and action. This prolonged time window of energization following novelty could hint at a mechanistic underpinning of enhanced vigour for approach and exploration frequently postulated for novelty seeking humans. In conclusion, we show that stimulus novelty enhances the speed of a cued motor action. We suggest this is likely to reflect an adaptation to changing environments but may also provide a source of maladaptive choice and impulsive behaviour.

Context-specific activation of hippocampus and SN/VTA by reward is related to enhanced long-term memory for embedded objects

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We tested if a rewarding context improved memory for embedded objects.

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Pattern-separation demands associated with context discrimination were manipulated.

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Contextual reward improved object memory in the similar condition alone.

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Improved memory was linked to context-related activation of the DG/CA3 and SN/VTA.

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SN/VTA engagement may determine whether memories are improved by contextual reward.

Animal studies indicate that hippocampal representations of environmental context modulate reward-related processing in the substantia nigra and ventral tegmental area (SN/VTA), a major origin of dopamine in the brain. Using functional magnetic resonance imaging (fMRI) in humans, we investigated the neural specificity of context-reward associations under conditions where the presence of perceptually similar neutral contexts imposed high demands on a putative hippocampal function, pattern separation. The design also allowed us to investigate how contextual reward enhances long-term memory for embedded neutral objects. SN/VTA activity underpinned specific context-reward associations in the face of perceptual similarity. A reward-related enhancement of long-term memory was restricted to the condition where the rewarding and the neutral contexts were perceptually similar, and in turn was linked to co-activation of the hippocampus (subfield DG/CA3) and SN/VTA. Thus, an ability of contextual reward to enhance memory for focal objects is closely linked to context-related engagement of hippocampal–SN/VTA circuitry.

Basal Ganglia Activity Mirrors a Benefit of Action and Reward on Long-Lasting Event Memory

The expectation of reward is known to enhance a consolidation of long-term memory for events. We tested whether this effect is driven by positive valence or action requirements tied to expected reward. Using a functional magnetic resonance imaging (fMRI) paradigm in young adults, novel images predicted gain or loss outcomes, which in turn were either obtained or avoided by action or inaction. After 24 h, memory for these images reflected a benefit of action as well as a congruence of action requirements and valence, namely, action for reward and inaction for avoidance. fMRI responses in the hippocampus, a region known to be critical for long-term memory function, reflected the anticipation of inaction. In contrast, activity in the putamen mirrored the congruence of action requirement and valence, whereas other basal ganglia regions mirrored overall action benefits on long-lasting memory. The findings indicate a novel type of functional division between the hippocampus and the basal ganglia in the motivational regulation of long-term memory consolidation, which favors remembering events that are worth acting for.

How beliefs about self-creation inflate value in the human brain

Humans have a tendency to overvalue their own ideas and creations. Understanding how these errors in judgement emerge is important for explaining suboptimal decisions, as when individuals and groups choose self-created alternatives over superior or equal ones. We show that such overvaluation is a reconstructive process that emerges when participants believe they have created an item, regardless of whether this belief is true or false. This overvaluation is observed both when false beliefs of self-creation are elicited (Experiment 1) or implanted (Experiment 2). Using brain imaging data we highlight the brain processes mediating an interaction between value and belief of self-creation. Specifically, following the creation manipulation there is an increased functional connectivity during valuation between the right caudate nucleus, where we show BOLD activity correlated with subjective value, and the left amygdala, where we show BOLD activity is linked to subjective belief. Our study highlights psychological and neurobiological processes through which false beliefs alter human valuation and in doing so throw light on a common source of error in judgements of value.

Action and valence modulate choice and choice-induced preference change

Choices are not only communicated via explicit actions but also passively through inaction. In this study we investigated how active or passive choice impacts upon the choice process itself as well as a preference change induced by choice. Subjects were tasked to select a preference for unfamiliar photographs by action or inaction, before and after they gave valuation ratings for all photographs. We replicate a finding that valuation increases for chosen items and decreases for unchosen items compared to a control condition in which the choice was made post re-evaluation. Whether choice was expressed actively or passively affected the dynamics of revaluation differently for positive and negatively valenced items. Additionally, the choice itself was biased towards action such that subjects tended to choose a photograph obtained by action more often than a photographed obtained through inaction. These results highlight intrinsic biases consistent with a tight coupling of action and reward and add to an emerging understanding of how the mode of action itself, and not just an associated outcome, modulates the decision making process.

Is choice-induced preference change long lasting?

The idea that decisions alter preferences has had a considerable influence on the field of psychology and underpins cognitive dissonance theory. Yet it is unknown whether choice-induced changes in preferences are long lasting or are transient manifestations seen in the immediate aftermath of decisions. In the research reported here, we investigated whether these changes in preferences are fleeting or stable. Participants rated vacation destinations before making hypothetical choices between destinations, immediately afterward, and 2.5 to 3 years later. We found that choices altered preferences both immediately after being made and after the delay. These changes could not be accounted for by participants' preexisting preferences, and they occurred only when participants made the choices themselves. Our findings provide evidence that making a decision can lead to enduring change in preferences.

The effect of steam sterilisation at 134 degrees C on light intensity provided by fibrelight Macintosh laryngoscopes

We studied the repeated effect of sterilisation on light intensity in laryngoscopes from Penlon, Riester, Heine (two different blades), Medicon and Upsher. Light intensity was measured by a light meter using two methods. Measurements were performed before the decontamination procedure was carried out and subsequently after each series of 25 procedures until a total of 200 cycles was reached. Using method 1 (and 2), the reduction in light intensity after 200 cycles was 100% (100%; no light emitted), 37% (13%), 75% (69%), 79% (60%), 37% (14%) and 63% (55%) for each blade, respectively.

Medaka spalt acts as a target gene of hedgehog signaling

In vertebrates, pattern formation in the eye, central nervous system, somites, and limb depends on hedgehog activity, but a general target gene controlled by hedgehog in all these signaling centers has remained largely elusive. The medaka fish gene spalt encodes a zinc-finger transcription factor, which is expressed in all known hedgehog signaling centers of the embryo and in the organizer region at the midbrain-hindbrain boundary. We show that the spalt expression domains expand in response to ectopic hedgehog activity and narrow in the presence of protein kinase A activity, an antagonist of hedgehog signaling, indicating that spalt is a hedgehog target gene. Our results also suggest a signaling mechanism for anterior-posterior patterning of the vertebrate brain that controls spalt expression at the midbrain-hindbrain boundary in a protein kinase A dependent manner likely to involve an unknown member of the hedgehog family.

Alternating nevirapine and zidovudine treatment of human immunodeficiency virus type 1-infected persons does not prolong nevirapine activity

The potential use of an alternating treatment strategy with nevirapine and zidovudine in prolonging the antiretroviral effects of nevirapine was evaluated. Ten human immunodeficiency virus type 1 (HIV-1)-infected p24 antigen-positive persons who had not received prior antiretroviral therapy were treated for 9-13 weeks with an alternating regimen of 1 week of nevirapine (200 mg/day) and 3 weeks of zidovudine (600 mg/day). Serum p24 antigen levels declined during the first week of nevirapine treatment (median, 59%); however, subsequent courses of nevirapine were characterized by rising p24 antigen levels, while antigen levels remained stable or declined during zidovudine treatment. Serum beta 2-microglobulin levels and CD4+ cell counts exhibited similar responses. HIV-1 isolates obtained from 2 patients revealed 40- and 1000-fold reductions in nevirapine sensitivity after 8 weeks. These findings demonstrate that alternating treatment with zidovudine and nevirapine does not prolong the effectiveness of nevirapine and does not prevent the development of nevirapine resistance.

Radical vitrectomy and silicone-oil injection in the treatment of proliferative vitreoretinopathy following retinal detachment

Eighteen consecutive patients with proliferative vitreoretinopathy following retinal detachment were treated with radical pars-plana vitrectomy and silicone oil injection. At least 6 months follow-up demonstrated fully attached retinas in 12 patients, partly attached retinas in 3 patients and primary failure in 3 patients. The visual fields revealed serious defects in 50% of those patients with attached retinas. The expected complications such as cataract (100%), glaucoma, corneal decompensation and subretinal oil were seen as well, but the complication rate is expected to diminish with newer surgical techniques.

Healon as intravitreal substitute in retinal detachment surgery in 40 patients

Forty patients with hypotony during retinal detachment surgery were treated with intravitreal Healon. Healon was very well tolerated, except for a transient rise in the intra-ocular pressure in 19 out of 40 patients. A relationship between the rise in intra-ocular pressure and the mount of Healon used was not found. Temporal corneal decompensation occurred in two patients. Early cases of proliferative vitreo-retinopathy with retinal detachment were treated successfully with external retinal-detachment surgery and intravitreal Healon.

Comparison of vitreous replacement with Healon and with HPMC in rabbits' eyes

Ten rabbits underwent vitreous aspiration and replacement by either Healon or Hydroxy Propyl Methyl Cellulose 2%. Four weeks' observation did not reveal noticeable differences between Healon and HPMC with regard to anterior chamber reaction, intra-ocular pressure or cataract. The vitreous reaction in eyes with HPMC was much more severe than in Healon eyes, with typical white precipitates and vitreous bands. Post-mortem examination confirmed the clinical findings.

Congenital corneal opacity (Peters' anomaly) combined with buphthalmos and aniridia

A case history of a newborn infant is discussed. At birth he showed bilateral buphthalmos with aniridia and congenital corneal opacities, agreeing with Peters' anomaly. A keratoplasty was performed. The dysgenesis mesenchymalis classification is mentioned briefly. High resolution banding technique of chromosomes revealed no abnormality.

Interspecific crossability studies in poplars

Pollen-stigma interactions were studied with scanning electron microscopy in intraspecific and intersectional crosses of Populus tremuloides (Sect. LEUCE); P. deltoides, P. nigra (Sect. AIGEIROS); and P. trichocarpa (Sect. TACAMAHACA). Intraspecific variation in hydration, size of hydrated pollen grains, and tube morphology is described. Exine sculpture in P. tremuloides was densely spinulate or scabrate, in P. trichocarpa densely reticulate, in the other species somewhat intermediate. In six of seven intersectional cross combinations pollen-tube behavior on the stigmatic surface at 5-22 hours after pollination was the same as in conspecific matings; in P. tremuloides x P. trichocarpa crosses, the percentage of twisted and bulging tubes was significantly higher. Irradiated mentor pollen did not affect pollentube behavior of adjacent incompatible pollen, but increased hybrid seedling production in interspecific crosses. By contrast, hexane treatment of pollen or stigma, and the spraying of catkins with gibberellic acid or naphtalene acetic acid were ineffective. The results are discussed in relation to several mechanisms presumed to be involved in restricting gene exchange among poplar species; and in relation to Hogenboom's (1973) incongruity concept.