Prediction of foot clearance parameters as a precursor to forecasting the risk of tripping and falling

Tripping and falling is a serious health problem for older citizens due to the high medical costs incurred and the high mortality rates precipitated mostly by hip fractures that do not heal well. Current falls prevention technology encompasses a broad range of interventions; both passive (e.g., safer environments, hip protectors) and active (e.g., sensor-based fall detectors) which attempt to reduce the effects of tripping and falling. However the majority of these interventions minimizes the impact of falls and do not directly reduce the risk of falling. This paper investigates the prediction of gait parameters related to foot-to-ground clearance height during the leg swing phase which have been physically associated with tripping and falling risk in the elderly. The objective is to predict parameters of foot trajectory several walking cycles in advance so that anticipated low foot clearance could be addressed early with more volitional countermeasures, e.g., slowing down or stopping. In this primer study, foot kinematics was recorded with a highly accurate motion capture system for 10 healthy adults (25-32 years) and 11 older adults (65-82 years) with a history of falls who each performed treadmill walking for at least 10 min. Vertical foot displacement during the swing phase has three characteristic inflection points and we used these peak values and their normalized time as the target prediction values. These target variables were paired with features extracted from the corresponding foot acceleration signal (obtained through double differentiation). A generalized regression neural network (GRNN) was used to independently predict the gait variables over a prediction horizon (number of gait cycles ahead) of 1-10 gait cycles. It was found that the GRNN attained 0.32-1.10 cm prediction errors in the peak variables and 2-8% errors in the prediction of normalized peak times, with slightly better accuracies in the healthy group compared to elderly fallers. Prediction accuracy decreased linearly (best fit) at a slow rate with increasing prediction horizon ranging from 0.03 to 0.11 cm per step for peak displacement variables and 0.34 × 10(-3) - 1.81 × 10(-3)% per step for normalized peak time variables. Further time series analysis of the target gait variable revealed high autocorrelations in the faller group indicating the presence of cyclic patterns in elderly walking strategies compared to almost random walking patterns in the healthy group. The results are promising because the technique can be extended to portable sensor-based devices which measure foot accelerations to predict the onset of risky foot clearance, thus leading to a more effective falls prevention technology.     

Effects of an Internet-based intervention for subthreshold eating disorders: a randomized controlled trial

BackgroundWomen reporting initial eating disorder (ED) symptoms are at highest risk for the development of an eating disorder. Preventive interventions should, therefore, be specifically tailored for this subgroup.AimsTo adapt and evaluate the effects of the Internet-based prevention program “Student Bodies?” for women with symptoms of disordered eating and/or subthreshold eating disorder (ED) syndromes.Method126 women, reporting subthreshold ED symptoms (high weight and shape concerns and below threshold bingeing, purging, chronic dieting or several of these symptoms) were randomly assigned to a Student Bodies?+ (SB+) intervention or a wait-list control group and assessed at pre-intervention, post-intervention, and 6-month follow-up. “Student Bodies?” was adapted to be suitable for subthreshold EDs. Main outcome measures were attitudes and symptoms of disordered eating. Pre-follow-up data were analyzed by ANCOVAS with mixed effects.ResultsAt 6-month follow-up, compared to participants in the control group, participants in the intervention group showed significantly greater improvements on ED-related attitudes. Intervention participants also showed 67% (95% CI = 20–87%) greater reductions in combined rates of subjective and objective binges, and 86% (95% CI = 63–95%) greater reduction in purging episodes. Also, the rates of participants abstinent from all symptoms of disordered eating (restrictive eating, binge eating and any compensatory behavior) were significantly higher in the intervention group (45.1% vs. 26.9%). Post-hoc subgroup analyses revealed that for participants with binge eating the effect on EDE-Q scores was larger than in the pure restricting subgroup.ConclusionThe adapted “SB+” program represents an effective intervention for women with subthreshold EDs of the binge eating subtype.     

Causal imprinting in causal structure learning

Suppose one observes a correlation between two events, B and C, and infers that B causes C. Later one discovers that event A explains away the correlation between B and C. Normatively, one should now dismiss or weaken the belief that B causes C. Nonetheless, participants in the current study who observed a positive contingency between B and C followed by evidence that B and C were independent given A, persisted in believing that B causes C. The authors term this difficulty in revising initially learned causal structures "causal imprinting." Throughout four experiments, causal imprinting was obtained using multiple dependent measures and control conditions. A Bayesian analysis showed that causal imprinting may be normative under some conditions, but causal imprinting also occurred in the current study when it was clearly non-normative. It is suggested that causal imprinting occurs due to the influence of prior knowledge on how reasoners interpret later evidence. Consistent with this view, when participants first viewed the evidence showing that B and C are independent given A, later evidence with only B and C did not lead to the belief that B causes C.     

The effect of cognitive behavior therapy on decision making in adolescents who self-harm: a pilot study

Research shows poor decision making in adolescents who self-harm and a positive correlation between decision-making abilities and duration since last self-harm episode. This exploratory study investigated whether decision making in self-harming adolescents could be improved through treatment with a novel cognitive behavior therapy (CBT). It also investigated whether improvement in decision making following treatment was linked to self-harm cessation. Adolescent self-harmers receiving CBT (n = 24) or no treatment (n = 9) and healthy controls (n = 22) were longitudinally compared on the Iowa gambling task (IGT). Significant IGT improvements were only observed for adolescents who self-harm following CBT. CBT may benefit adolescent self-harmers and generate decision-making improvements.     

The development of causal categorization

Two experiments examined the impact of causal relations between features on categorization in 5- to 6-year-old children and adults. Participants learned artificial categories containing instances with causally related features and noncausal features. They then selected the most likely category member from a series of novel test pairs. Classification patterns and logistic regression were used to diagnose the presence of independent effects of causal coherence, causal status, and relational centrality. Adult classification was driven primarily by coherence when causal links were deterministic (Experiment 1) but showed additional influences of causal status when links were probabilistic (Experiment 2). Children's classification was based primarily on causal coherence in both cases. There was no effect of relational centrality in either age group. These results suggest that the generative model (Rehder, 2003a) provides a good account of causal categorization in children as well as adults.     

The role of defeat and entrapment in depression, anxiety, and suicide

Defeat and entrapment are psychological constructs that have played a central role in evolutionary accounts of depression. These concepts have since been implicated in theoretical accounts of anxiety disorders and suicidality. The current article reports on a systematic review of the existing research investigating the links among defeat, entrapment, and psychopathology in the domains of depression, suicidality, posttraumatic stress disorder (PTSD), and other anxiety syndromes. Fifty-one original research articles were identified and critically reviewed. There was strong convergent evidence for a link with depressive symptoms, across a variety of clinical and nonclinical samples. Preliminary support for an association with suicidality was also observed, with effects not readily explainable in terms of comorbid depression. There was strong evidence for an association between defeat and PTSD, although this may have been partly accounted for by comorbid depression. The findings for other anxiety disorders were less consistent. There was, however, evidence that social anxiety in individuals with psychosis may be related to perceptions of entrapment. Overall, there was evidence that perceptions of defeat and entrapment were closely associated with various forms of human psychopathology. These effects were often in the moderate to large range and superseded the impact of other environmental and psychological stressors on psychopathology. We provide a unified theoretical model of how defeat and entrapment may contribute to these different psychopathological conditions. Clinical implications and avenues for future research are discussed.     

When fit fosters favoring: The role of private self-focus

The present research extends work on the ‘the value from fit’ principle by showing that regulatory fit effects on persuasion and behavioral compliance are stronger for people high, as opposed to low, in private self-focus. Previous research has shown that people high in private self-focus are strongly affected by external information. In the current work, we demonstrated that people high (vs. low) in private self-focus are more persuaded by information that matches (vs. mismatches) activated self-knowledge.     

Stability and Invariance of Psychopathic Traits from Late Adolescence to Young Adulthood

The current study examined the longitudinal stability and invariance of psychopathic traits in a large community sample of male twins from ages 17 to 23. Participants were assessed across 6 years to gauge the stability and measurement invariance of the Minnesota Temperament Inventory (MTI), a Cleckley-based measure of psychopathic personality traits, and how family functioning and externalizing behavior were linked to these traits. A latent variable approach was used to model the structure of the MTI and provide a statistical test of measurement invariance across time. The results revealed support for invariance and moderate to strong stability of the MTI factors, which showed significant associations with the external correlates in late adolescence but not early adulthood.     

The cultural narratives of Francophone and Anglophone Quebecers: using a historical perspective to explore the relationships among collective relative deprivation, in-group entitativity, and collective esteem

Responding to calls to contextualize social psychological variables in history, the present research examines the relationship between collective relative deprivation and collective esteem using a historical perspective. We hypothesized that collective relative deprivation perceived to be experienced during an important low-point in a group's history serves to define the group's current collective identity, which is in turn associated with collective esteem. In Study 1, cultural narrative interviews were conducted with Francophone and Anglophone Quebecers in order to identify key historical chapters for these groups and to examine the extent to which historical low-points were identity-defining features of their narratives. In Study 2, using the information obtained from these narratives, collective relative deprivation was explored across group members' perceived histories and related to current in-group entitativity and collective esteem. The relationship between collective relative deprivation thought to be experienced by one's group during a historical low-point and collective esteem was positive for both Anglophone and Francophone Quebecers and was mediated by in-group entitativity. Collective relative deprivation perceived to be experienced during a historical low-point serves to define one's collective identity, which is in turn associated with greater collective esteem.