A statistical approach to sensorimotor strategies: conjugate cross-correlations

A simple method, based on cross-correlation functions (CCFs) between two time series of kinematic or physiological measurements, is proposed for the analysis of multisegmental movements. Special emphasis is placed on measuring accelerations. When the movements of two body segments are coordinated but consistently time lagged, their CCF displays a peak at the corresponding time abscissa. The reproducible positions of the peaks reflect biomechanical or physiological constraints. Several significantly large peaks can be observed in a CCF. It is possible to identify coordinated movements involving more than two segments by applying simple rules of compatibility between the time lags and between the signs of the correlation peaks. With the method proposed, it is possible to determine the signs of relative variation and the time lags of the successive statistically correlated segmental movements. This is particularly useful in the case of both continuous and periodic sensorimotor control, where classical poststimulus methods cannot be applied. Unlike the classical poststimulus methods, this method does not require a time origin, and it is not necessary to monitor the muscles or even to specify exactly which ones are involved. The method is also applicable to experiments involving a time origin (e.g., and applied perturbation), although in this case it is less accurate than the averaging technique. Individual postural strategies can be identified, which suggests some interesting potential applications of the method to clinical studies.     

Lexical and semantic fluency discrepancy scores in aMCI and early Alzheimer's disease

Episodic memory is compromised in amnestic mild cognitive impairment (aMCI), but lesser deficits in other cognitive domains are also commonly observed and may be helpful in identifying this group. The relative difference in performance on lexical and semantic fluency tasks may be a sensitive and specific measure in aMCI and early Alzheimer's disease (AD). We compared four groups of participants, 35 early AD, 47 aMCI, 24 healthy controls, and 18 depressive out‐patient controls, on semantic and lexical fluency as well as other neuropsychological tests. Early AD and aMCI patients showed a distinct pattern of semantic impairment in the two fluency measures compared with the healthy and depressive controls. The findings implicate early failure of the semantic memory system in aMCI and AD and suggest that consideration of the discrepancy in performance on semantic and lexical fluency measures may help in the early identification of AD.     

Spatial memory of domestic dogs (Canis familiaris) for hidden objects in a detour task

Spatial memory of domestic dogs (Canis familiaris) for hidden objects was investigated via a visible displacement problem of object permanence with a detour paradigm. Experiment 1 showed that dogs were able to spontaneously locate a disappearing object in a detour situation. In Experiments 2 and 3, dead reckoning and allocentric spatial information were put in conflict. Results revealed that dogs simultaneously encoded both sources of information when they had to bypass an obstacle to locate a hidden object. Experiment 3 also revealed that, over the course of testing, dogs gradually learned to rely predominantly on allocentric cues when the detour involved several reorientations. The current study reveals that spatial memory of dogs for hidden objects in a detour task was guided by flexibility in processing spatial information. Dogs could simultaneously encode dead reckoning and allocentric information to locate a disappearing object and used them hierarchically according to the complexity of the detour they encountered in the environment.     

The buffering power of overt socially supportive and unsupportive behaviors from the significant other on posttraumatic stress disorder individuals’ emotional state

Background and objectives: Social support is one of the three strongest predictors of posttraumatic stress disorder (PTSD). In the present study, we aimed to assess the buffering power of overt socially supportive and unsupportive behaviors from the significant other, in a group with PTSD and a comparison group. Design and methods: A total of 46 individuals with PTSD and 42 individuals with obsessive-compulsive disorder (OCD) or panic disorder (PD) completed diagnostic interviews and an anxiety-oriented social interaction with a significant other. Heart rate of participants was continuously measured during this interaction and overt social behaviors from the significant other were recorded on videotape and coded using a validated system. Results: Changes in heart rate in PTSD participants correlated negatively with changes in overt socially supportive behaviors from their significant other (r from ?.36 to ?.50, p?<?.05), while changes in overt unsupportive social behaviors from their significant other did not yield any significant correlation (r from ?.01 to .05, p?>?.05). No such statistically significant association emerged in the group with OCD or PD (r from .01 to ?.27, p?>?.05). Conclusions: This study sustain the buffering power of overt supportive behaviors from the significant other on heart rate changes in PTSD.     

Healthcare utilization following cognitive-behavioral treatment for panic disorder with agoraphobia

The aim of this study was to examine the overall changes in healthcare services utilization after providing an empirically supported cognitive-behavioral treatment for panic disorder with agoraphobia. Data on healthcare utilization were collected for a total of 84 adults meeting DSM-IV criteria. Participants were completers of a cognitive-behavioral treatment for panic disorder with agoraphobia. Data on utilization of healthcare services and medication were obtained from semi-structured interviews from baseline to 1-year after treatment. Results of the Friedman non-parametric analysis reveal a significant decrease in overall and mental health-related costs following treatment. This study shows a significant reduction in healthcare costs following cognitive behavior therapy for panic disorder with agoraphobia. More studies are needed to examine the potential long-term cost-offset effect of empirically supported treatments for panic disorder.     

Inferential confusion in obsessive-compulsive disorder: the inferential confusion questionnaire

The current article represents the further validation of the construct of inferential confusion amongst clinical samples. Inferential confusion is proposed to be a meta-cognitive confusion particularly relevant to obsessive compulsive disorder (OCD) that leads a person to confuse an imagined possibility with an actual probability. As such, it conceptualizes OCD as a form of belief disorder similar to a delusion or overvalued idea that is a product of distorted reasoning processes. In contrast, other cognitive models of OCD emphasize a phobic model of development in OCD, and thus consider the exaggerated interpretation of intrusions as an essential element in OCD. The present study administered a revised version of the Inferential Confusion Questionnaire, and the Obsessive Belief Questionnaire (OBQ), to a total of 183 participants in three clinical groups and a non-clinical control group. Results suggest that OCD, at least in part, follows a non-phobic model of development with inferential confusion significantly related to obsessive-compulsive symptoms independently of cognitive domains as measured by the OBQ, and mood states. Further, scores on inferential confusion were particularly high in those with OCD and delusional disorder as compared to anxious and non-clinical controls.     

Impaired oral reading in two atypical dyslexics: a comparison with a computational lexical-analogy model

A computational model of reading was developed based upon the notion that the structural relationship between orthography and phonology is of greater importance than the dimension of semantics for the reading aloud of single words. Degradation of this model successfully simulated the reading performance of two patients with atypical acquired dyslexia. The first patient CAV, studied and described in the literature by Warrington in 1981, presented with unusual concrete word dyslexia, i.e., he had a category-specific reading deficit for concrete words compared with abstract words. The second patient BG is a phonological dyslexic who, although displaying a strong concreteness effect (concrete words read better than abstract words), was able to read functors individually perfectly well, a pattern that is rarely if ever seen. The computational model was used to generate a set of words for which it was predicted that BG would show no concreteness effect. The results of BG's reading of these words were consistent with this prediction, thereby providing greater support for the validity of the model. It is concluded that a computational approach that attempts not only to reproduce the core symptoms of the major varieties of acquired dyslexia but also to simulate clinical data from specific patients has much to contribute to the understanding of cognitive deficits and to the design of effective rehabilitation strategies.     

Direct and Indirect Effects of Caregiver Social Support on Adolescent Psychological Outcomes in Two South African AIDS-Affected Communities

Caregiver social support has been shown to be protective for caregiver mental health, parenting and child psychosocial outcomes. This is the first known analysis to quantitatively investigate the relationship between caregiver social support and adolescent psychosocial outcomes in HIV‐endemic, resource–scarce Southern African communities. A cross‐sectional household survey was conducted over 2009–2010 with 2,477 South African adolescents aged 10–17 and their adult caregivers (18 years or older) in one urban and one rural community in South Africa’s KwaZulu‐Natal province. Adolescent adjustment was assessed using adult caregiver reports of the Strengths and Difficulties questionnaire (SDQ), which measures peer problems, hyperactivity, conduct problems, emotional symptoms and child prosocial behavior. Hierarchical linear regressions and multiple mediation analyses, using bootstrapping procedures, were conducted to assess for: (a) direct effects of more caregiver social support on better adolescent psychosocial wellbeing; and (b) indirect effects mediated by better parenting and caregiver mental health. Direct associations (p < .001), and indirect associations mediated through better parenting, were found for all adolescent outcomes. Findings reinforce the importance of social support components within parenting interventions but also point to scope for positive intervention on adolescent psychosocial wellbeing through the broader family social network.