Harnessing the Power of a Novel Program for Dynamic Balance Perturbation with Supported Body Weight

Abstract

Self-initiated postural adjustments commonly occur in daily life. To accessibly measure this type of dynamic balance, we developed a simple computer program to induce virtual perturbations and combined it with a commercially available balance board and portable EMG system to measure resulting self-initiated postural adjustments. When performing perturbed balance tests, safety harness with body weight support (BWS) is often used. However, influences of these harnesses on postural reactions are not well known. This study investigated the sensitivity of our assessment tool under different BWS conditions and muscle responses during postural adjustments following perturbation at different directions. Fifteen neurologically intact participants performed self-initiated postural adjustments under conditions with: (1) no harness; (2) harness with no BWS; and (3) harness with 10% BWS. Postural adjustment time and muscle activities of the lower leg were measured. We observed significant increases in postural adjustment time in the harness with no BWS condition and differneces in lower leg muscles response to virtual perturbation. Our findings suggest that the combination of our customized program with EMG is a sensitive and convenient tool to measure postural adjustments that approximate real-world scenarios. This method can be used with light body weight support to ensure safety without influencing muscle synergies.     

Non-symbolic arithmetic in adults and young children

Five experiments investigated whether adults and preschool children can perform simple arithmetic calculations on non-symbolic numerosities. Previous research has demonstrated that human adults, human infants, and non-human animals can process numerical quantities through approximate representations of their magnitudes. Here we consider whether these non-symbolic numerical representations might serve as a building block of uniquely human, learned mathematics. Both adults and children with no training in arithmetic successfully performed approximate arithmetic on large sets of elements. Success at these tasks did not depend on non-numerical continuous quantities, modality-specific quantity information, the adoption of alternative non-arithmetic strategies, or learned symbolic arithmetic knowledge. Abstract numerical quantity representations therefore are computationally functional and may provide a foundation for formal mathematics.     

Lexical and Metrical Stress in Word Recognition: Lexical or Pre-lexical Influences?

The influence of lexical stress and/or metrical stress on spoken word recognition was examined. Two experiments were designed to determine whether response times in lexical decision or shadowing tasks are influenced when primes and targets share lexical stress patterns (JUVenile–BIBlical [Syllables printed in capital letters indicate those syllables receiving primary lexical stress.]). The results did not support an effect of lexical stress on the organization of lexical memory. In Experiment 3 primes and targets whose first syllables shared lexical stress only (MUDdy–PASta), metrical stress only (alTHOUGH–PASta), both cues (LECtern–PASta), or neither cue (conTROL–PASta) revealed no priming effect. However, targets whose first syllables were strong were responded to faster than targets whose first syllables were weak. Experiment 4 manipulated the metrical stress patterns of bi-syllabic primes and targets. Targets with strong–weak metrical stress patterns were responded to more quickly than those with strong–strong or weak–strong patterns. Although the priming paradigm did not reveal an influence of lexical and metrical stress on the organization of lexical memory, the data do support an influence of strong syllables on the processing of auditorily presented words.     

Novel metaphors appear anomalous at least momentarily: evidence from N400

This study addresses a central question in perception of novel figurative language: whether it is interpreted intelligently and figuratively immediately, or only after a literal interpretation fails. Eighty sentence frames that could plausibly end with a literal, truly anomalous, or figurative word were created. After validation for meaningfulness and figurativeness, the 240 sentences were presented to 11 subjects for event related potential (ERP) recording. ERP's first 200 ms is believed to reflect the structuring of the input; the prominence of a dip at around 400 ms (N400) is said to relate inversely to how expected a word is. Results showed no difference between anomalous and metaphoric ERPs in the early window, metaphoric and literal ERPs converging 300-500 ms after the ending, and significant N400s only for anomalous endings. A follow-up study showed that the metaphoric endings were less frequent (in standardized word norms) than were the anomalous and literal endings and that there were significant differences in cloze probabilities (determined from 24 new subjects) among the three ending types: literal > metaphoric > anomalous. It is possible that the low frequency of the metaphoric element and lower cloze probability of the anomalous one contributed to the processes reflected in the early window, while the incongruity and near-zero cloze probability of the anomalous endings produced an N400 effect in them alone. The structure or parse derived for metaphor during the early window appears to yield a preliminary interpretation suggesting anomaly, while semantic analysis reflected in the later window renders a plausible figurative interpretation.     

Psychoanalytic patients in the U.S., Canada,and Australia: II. A DSM-III-R validation study

A study was conducted to validate our previous work on the DSM-III-R disorders diagnosed in patients in psychoanalysis in the U.S., Canada, and Australia and to determine which specific mood, anxiety, and personality disorders were the most common in these patients. The earlier study consisted of three surveys of psychoanalytic practice that together obtained data on 1,718 patients, through extensive mail surveys to analysts in the three countries. In the validation study, 206 patients were diagnosed using a different technique. Analysts similar in important respects to those who participated in the original surveys rated patients diagnostically before and after DSM-III-R training. After training, no significant changes appeared in the rates for any of the specific mood disorders. For the thirty disorders examined, training effects decreased the identification of the generalized anxiety disorder, and increased the identification of three personality disorders: avoidant, dependent, and personality disorder not otherwise specified. Thus, analysts slightly underdiagnosed the number of personality disorders, and some "anxious" patients appear to have qualified for personality disorders. Some limitations of the DSM-III-R notion of narcissistic personality are discussed, as are the importance and stability of the self-defeating (masochistic) personality disorder. The most common Axis I disorder in psychoanalytic patients was dysthymia, followed by major depression, recurrent. This study reinforces the findings of the original three surveys. Minor corrections were developed to adjust the original three surveys.     

The role of collaborative planning in children's source-monitoring errors and learning.

The aim of this research was to provide empirical evidence for a cognitive process that may contribute to children's learning from another person. A cornerstone of Vygotsky's sociocultural theory is that knowledge is internalized from others; however, the cognitive processes that support this transformation are underspecified. In a series of three studies, kindergarten children (mean age 5 years 8 months) participated in a categorization task with an adult in several collaborative and noncollaborative conditions and then were tested on their memory of who had performed which actions in the task. After the memory task, children were asked to recategorize the items on their own. Source-monitoring patterns and children's learning varied across conditions according to predictions. A measure of recoding was related to children's planning language that, in turn, predicted learning among the children. The results suggest that one process that contributes to children's internalization of knowledge may involve recoding of agent information and that recoding can be indexed by source-monitoring performance.     

Response variability in attention-deficit disorders

Reaction times in a mental rotation task were measured across a diverse population that sorted into two groupings based on overall variability. Although both the low- and the high-variance groups produced data that displayed the trends typical of mental rotation, the two groups' reaction time sequences had very different autocorrelation functions. Power spectra derived from the two groups' data showed the presence of distinctive noise processes with long memory. Normal levels of variance were associated with 1/f noise, whereas high-variance data had substantial traces of random walk contour. These findings provide new perspectives on cognitive assessments of attention dysfunction.     

The PHQ-9 as a brief assessment of lifetime major depression

The Patient Health Questionnaire-9 (PHQ-9; R. L. Spitzer, K. Kroenke, J. B. W. Williams, & The Patient Health Questionnaire Primary Care Study Group, 1999), modified to ask about the worst period of depression lifetime, was validated against lifetime mood disorder diagnoses established by the Structured Clinical Interview for DSM-IV (SCID; M. B. First, R. L. Spitzer, M. Gibbon, & J. B. W. Williams, 2001) in 526 participants. PHQ-9 dichotomous scores corresponded highly with major depressive episode (MDE) Criterion A, MDE, and major depressive disorder (MDD), odds ratios >or= 9.5, and area under the receiver operating characteristic curve (AUC) >or= 0.84. The continuous scale score was higher in participants who did (M=17.14, SD=7.36) than in those who did not (M=6.05, SD=6.29) meet MDE Criterion A, t(524)=18.09, p<.001; was correlated with number of MDE Criterion A symptoms, r(525)=.67, p<.001; and detected MDE Criterion A (AUC=0.88). The PHQ-9 as a lifetime measure may be used to complement or replace more costly interview assessments.     

Active and Avoidant Coping and Coping Efficacy as Mediators of the Relation of Maternal Involvement to Depressive Symptoms among Urban Adolescents

Our study tested an extension of the social resource model in an urban sample of 129 African American and 114 European American adolescents. Maternal involvement was positively related to the use of active and avoidant coping strategies among youth of both ethnicities. Additionally, use of active coping strategies was related to greater coping efficacy, which, in turn, was associated with less depressive symptomatology. For African Americans, avoidant coping was related to greater coping efficacy, which, in turn, was associated with less depressive symptoms. For European Americans, avoidant coping was not significantly related to coping efficacy. Our findings underscore the importance of examining developmental models across ethnic/racial groups and suggest that adolescent mental health programs may benefit from culturally sensitive attention to coping beliefs and practices.