Postural sway and joint kinematics during quiet standing are affected by lumbar extensor fatigue

The purpose of this study was to investigate changes in postural sway and strategy elicited by lumbar extensor muscle fatigue. Specifically, changes in center of mass (COM), center of pressure (COP), and joint kinematics during quiet standing were determined, as well as selected cross correlations between these variables that are indicative of movement strategy. Twelve healthy male participants stood quietly both before and after exercises that fatigued the lumbar extensors. Whole-body movement and ground reaction force data were recorded and used to calculate mean body posture and variability of COM, COP, and joint kinematics during quiet standing. Three main findings emerged. First, participants adopted a slight forward lean post-fatigue as evidenced by an anterior shift of the COM and COP. Second, post-fatigue increases in joint angle variability were observed at multiple joints including joints distal to the fatigued musculature. Despite these increases, anterior-posterior (AP) ankle angle correlated well with AP COM position, suggesting the body still behaved similar to an inverted pendulum. Third, global measures of sway based on COM and COP were not necessarily indicative of changes in individual joint kinematics. Thus, in trying to advance our understanding of how localized fatigue affects movement patterns and the postural control system, it appears that joint kinematics and/or multivariate measures of postural sway are necessary.     

Pseudodementia: A slow death

The clinical term pseudodementia has remained a permanent nosological entity in the literature for over 100 years. Indeed, recognition of the fact that clinical symptoms associated with reversible neuropsychiatric conditions can mimic irreversible disorders was known as early as the middle of the 19th century. The importance of the term lies in the inherent assumption that the presenting dementia is not real, or is at least reversible, and therefore treatable. Nonetheless, there continues to be controversy regarding the validity and appropriate clinical use of the term. This article reviews the evolution and clinical utility of the term pseudodementia and attempts to redirect investigative efforts toward an understanding of the neuroanatomical substrates that underlie depression and cognitive impairment in the elderly. Based on a critical analysis of the relevant literatures, a subcortical-frontal neuroanatomical substrate of late-life depression is supported. Further, the presence of leukoaraiosis, as measured by magnetic resonance imaging, is proposed as a potential neurobiological marker that contributes to the depressed mood, cognitive impairment, and later cognitive deterioration of some elderly depressed.     

Measuring depressive symptomatology of patients referred to a behavioral medicine clinic: Concordance of self-report measures

We measured depressive symptomatology of 134 outpatient veterans treated within a Behavioral Medicine Clinic utilizing three reliable instruments with depression subscales: Minnesota Multiphasic Personality Inventory (MMPI), Derogatis Stress Profile (DSP), and Symptom Checklist 90—Revised (SCL-90-R). Results indicate that although the instruments correlate significantly, they differ in sensitivity to depression and are clinically discordant. The MMPI classified a substantially higher number of patients as depressed than either the DSP or SCL-90-R. The present study argues that the discrepancy in clinical concordance and sensitivity of the three depression scales has considerable implications for psychologists concerned with the assessment and treatment of depression.     

Aspects of body image perception in obese and normal-weight youngsters

Perceptual and projective aspects of body image in obese youngsters (not in psychological treatment) and normal-weight youngsters 8–9 years of age and 12–13 years of age were investigated. The results indicate that perceptual distortions in estimating various body dimensions of oneself are primarily a function of age rather than weight status. The accuracy of estimating the weight of peers and an adult showed an association with the sex of the subject. No group differences were found in terms of projective aspects of body image as measured by barrier and penetration responses. This study suggests that obese youngsters in the middle childhood and entering puberty periods in comparison to normal-weight youngsters of the same age do not manifest differences in perceptual factors of body image.     

Potential moral stigma and reactions to sexually transmitted diseases: evidence for a disjunction fallacy

Five experiments demonstrate how potential moral stigma leads people to underplay their susceptibility to sexually transmitted diseases (STDs) and dampens their interest in getting tested. After adding unprotected sex to a list of otherwise innocuous possible vectors for a disease, the authors found that infected people were perceived to be less moral (Experiment 1a), and individuals believed that if they had the disease, others would see them as less moral too (Experiment 1b). Adding this stigmatized vector also reduced reported testing intentions (Experiment 2) and perceived risk of exposure (Experiment 3)--a disjunction fallacy because adding a potential cause reduced estimated likelihood, in violation of basic probability rules. Finally, the authors replicated the effect in a computer virus analog (Experiment 4) and showed that it did not result from simply knowing that one has not engaged in the stigmatized behavior. Results suggest that avoidance of potential stigma can have dramatic health consequences, both for an individual's health decision and for health policy.     

Cultural illiteracy and the Internet.

The Internet has created different expectations regarding its possibilities as a tool for including groups that have heretofore been excluded from the modern world. But mere access to information does not necessarily imply correct and effective use of it. Despite the great increase in Internet access in previously excluded areas, expectations of inclusion have not been fulfilled. Research suggests that the effectiveness of Internet use varies among cultures, but all such studies analyze countries as a whole with no further breakdown. Yet it is known that within a given country there co-exist subcultures that differ both in language and social context. This paper presents a study that shows the correlation between different social subcultures and their Internet knowledge.     

An individual differences approach to the suggestibility of memory over time

We examined how certain personality traits might relate to the formation of suggestive memory over time. We hypothesised that compliance and trust relate to initial acceptance of misinformation as memory, whereas fantasy proneness might relate to integration of misinformation into memory after later intervals (relative to the time of exposure to misinformation). Participants watched an excerpt from a movie—the simulated eyewitness event. They next answered a recall test that included embedded misinformation about the movie. Participants then answered a yes/no recognition test. A week later, participants answered a second yes/no recognition test about the movie (each yes/no recognition test included different questions). Before both recognition tests, participants were warned about the misinformation shown during recall and were asked to base their answer on the movie excerpt only. After completing the second recognition test, participants answered questions from the Neuroticism Extroversion Openness Personality Inventory-3 (McCrae, Costa, & Martin, 2005) and Creative Experiences Questionnaire (Merckelbach, Horselenberg, & Muris, 2001). While compliance correlated with misinformation effects immediately after exposure to misinformation, fantasy-prone personality accounted for more of the variability in false recognition rates than compliance after a 1-week interval.     

Age and gender moderate the effects of localized muscle fatigue on lower extremity joint torques used during quiet stance

This study examined the effects of localized muscle fatigue, age, and gender on lower extremity joint torques used during quiet stance. Thirty-two participants performed exercises designed to fatigue the ankle plantarflexors, knee extensors, torso extensors, or shoulder flexors. Body kinematics and ground reaction forces were obtained both before and after the exercises, and joint torques were derived via inverse dynamics. Single joint fatigue affected torque variability at all lower extremity joints, with similar changes for both age groups. Males and females exhibited increased ankle torque variability after different tasks, with males showing more variability after ankle fatigue and females after shoulder and lumbar fatigue. Correlations between peak torques and torque variability differed between males and females and between age groups in certain cases. The results of this study suggested that both age and gender moderate the effects of fatigue on postural control and should be considered when developing strategies to prevent occupational falls.