Effect of walking surface,late-cueing,physiological characteristics of aging,and gait parameters on turn style preference in healthy,older adults

Turning while walking is a crucial component of locomotion, often performed on irregular surfaces with little planning time. Turns can be difficult for some older adults due to physiological age-related changes. Two different turning strategies have been identified in the literature. During step turns, which are biomechanically stable, the body rotates about the outside limb, while for spin turns, generally performed with closer foot-to-foot distance, the inside limb is the main pivot point. Turning strategy preferences of older adults under challenging conditions remains unclear. The aim of this study was to determine how turning strategy preference in healthy older adults is modulated by surface features, cueing time, physiological characteristics of aging, and gait parameters. Seventeen healthy older adults (71.5 ± 4.2 years) performed 90° turns for two surfaces (flat, uneven) and two cue conditions (pre-planned, late-cue). Gait parameters were identified from kinematic data. Measures of lower-limb strength, balance, and reaction-time were also recorded. Generalized linear (logistic) regression mixed-effects models examined the effect of (1) surface and cuing, (2) physiological characteristics of ageing, and (3) gait parameters on turn strategy preference. Step turns were preferred when the condition was pre-planned (p < 0.001) (model 1) and when the gait parameters of stride regularity and maximum acceleration decreased (p = 0.010 and p = 0.039, respectively) (model 3). Differences in turn strategy selection under dynamic conditions ought to be evaluated in future fall-risk research and rehabilitation utilizing real-world activity monitoring.     

Lateral asymmetries of orientation to track control in extrapersonal space

In an initial experiment, subjects were asked to make simple lateral lever responses to left and right verbal and arrow directions with the preferred hand. No asymmetries were found. In two subsequent experiments, subjects guided a track through a left or right turn in one of four orientations under instructions which were direct, compass points, or physical referents, by either a rotary or a discrete control. Asymmetries of direction of turn were observed. Rotary control produced a response bias towards the body midline, but independently of this factor there was a powerful bias towards right turns of track direction in extrapersonal space. Discrimination in the horizontal plane was more difficult than in the vertical plane especially when the instructions were compass points. Within the horizontal plane, together with the bias to right turns of track direction, a bias towards the right of the display was present. The interaction of these factors is believed to underlie reported errors in route finding and direction giving situations.     

Representational drawings of solid objects by young children

Two groups of children aged 6 and 8 years were given three tasks requiring graphical representations of solid geometric forms. These tasks were drawing from life models, copying from photographs, and copying from line drawings of these objects. Performance was assessed on the basis of level of approximation to correct perspective. Older children used more perspective features than younger children in their drawings. At all ages, the drawings from life were most difficult. Results on the two copying tasks were not consistent. Drawings made by copying photographs were either as advanced as or poorer than copies of line drawings. The results are explained in terms of the difficulties exhibited by young children in translating the three-dimensional scene to a two-dimensional picture plane and strategies adopted by them to cope with these problems.     

Prospective and retrospective memory in normal aging and dementia: an experimental study

Two experiments investigated the effects of normal aging and dementia on laboratory-based prospective memory (PM) tasks. Participants viewed a film for a later recognition memory task. In Experiment 1, they were also required either to say "animal" when an animal appeared in the film (event-based PM task) or to stop a clock every 3 min (time-based PM task). In both tasks, young participants were more successful than older participants, who were, in turn, more successful than patients with Alzheimer's disease (AD). For successful remembering in the time-based task, older participants and AD patients checked the clock more often than did young participants. In Experiment 2, participants were asked to reset a clock either when an animal appeared in the film (unrelated cue-action) or when a clock appeared in the film (related cue-action). Responses were faster in the related condition than in the unrelated condition. Again, there were differences in PM performance between young and older participants, and between older participants and AD patients. The observed deficits were not due to the forgetting of the PM task instructions in either experiment. Retrospective memory (RM) tasks (digit span, sentence span, free recall, and recognition) were more impaired by AD than were the PM tasks. Factor analysis revealed separate factors corresponding to RM and PM.     

Turn-taking and speech act patterns in the discourse of senile dementia of the Alzheimer's type patients

Conversational discourse patterns of 11 normal elderly and 11 senile dementia of the Alzheimer's type (SDAT) patients engaged in dyadic interaction with an examiner were examined. Differences in word usage, turn taking, and speech act production were investigated both for the two-subject groups and for the examiner's conversations with each group. Compensatory shifts in discourse by participants are identified. For the subject, differences were shown on words per turn with SDAT subjects speaking in shorter turns and in nonverbal responses with SDAT subjects using this strategy more frequently. Speech act categories of Requestives and Assertives also differed with SDAT subjects using more Requestives and fewer Assertives. The SDAT subjects had significantly more occurrences of unintelligible utterances. For the examiner, words per turn differed with the examiner using shorter turns with SDAT subjects. No differences were shown in the examiner's patterns of speech act usage, nonverbal responses, or intelligibility. In general, these results indicate significant discourse differences in the words per turn level for all participants and speech act levels of conversation for SDAT subjects. They also indicate generally maintained interaction patterns by speakers so that the discourse genre of conversation is sustained. The pattern of compensatory shifts in discourse suggests retained flexibility in the communication system of early and mid stage SDAT patients.     

Spatial exploration patterns determine navigation efficiency: trade-off between memory demands and distance travelled

A total of 41 participants explored a novel square-shaped environment containing five identical boxes each hiding a visually distinct object. After an initial free exploration the participants were required to locate the objects first in a predetermined and subsequently in an optional order task. Two distinct exploration strategies emerged: Participants explored either along the main axes of the room (axial), or in a more spatially spread, circular pattern around the edges of the room (circular). These initial exploration strategies influenced the optimality of spatial navigation performance in the subsequent optional order task. The results reflect a trade-off between memory demands and distance efficiency. The more sequential axial strategy resulted in fewer demands on spatial memory but required more distance to be travelled. The circular strategy was more demanding on memory but required less subsequent travelling distance. The findings are discussed in terms of spatial knowledge acquisition and optimality of strategy representations.     

Spatial exploration patterns determine navigation efficiency: Trade-off between memory demands and distance travelled

A total of 41 participants explored a novel square-shaped environment containing five identical boxes each hiding a visually distinct object. After an initial free exploration the participants were required to locate the objects first in a predetermined and subsequently in an optional order task. Two distinct exploration strategies emerged: Participants explored either along the main axes of the room (axial), or in a more spatially spread, circular pattern around the edges of the room (circular). These initial exploration strategies influenced the optimality of spatial navigation performance in the subsequent optional order task. The results reflect a trade-off between memory demands and distance efficiency. The more sequential axial strategy resulted in fewer demands on spatial memory but required more distance to be travelled. The circular strategy was more demanding on memory but required less subsequent travelling distance. The findings are discussed in terms of spatial knowledge acquisition and optimality of strategy representations.     

Influences of elbow,shoulder, trunk motion and temporospatial parameters on arm swing asymmetry of Parkinson's disease during walking

Arm swing asymmetry is commonly observed in early Parkinson's disease (PD) and has been found to be useful for early diagnosis. However, there are uncertainties about the nature of its relationships with gait parameters, especially shoulder and elbow motions. Therefore, this study explored how these relationships are different between PD and controls. Forty one early PD and 23 controls were included. Participants walked at self-selected speed for 3D motion analysis. Arm swing at the wrist (AS), temporospatial parameters and kinematics in elbow, shoulder and trunk were obtained. Amplitudes and asymmetries of these variables were compared between PD and control groups. PD group showed increased AS asymmetry, compared to controls. Multiple hierarchical regression analysis on AS asymmetry was conducted in order to investigate how PD influences on the relationship between AS asymmetry and other variables. In pooled data (PD and control group), asymmetries in elbow and shoulder range of motion (RoM) were significant predictors for AS asymmetry but walking speed and asymmetries in temporospatial parameters were not significant. Group effect (PD effect) was significantly mediated by only elbow RoM asymmetry. Interaction between group and elbow RoM asymmetry was statistically significant, indicating that group was an effect modifier for elbow RoM asymmetry effect on AS asymmetry. Conclusively, arm swing asymmetry measured at the wrist represents the involvement of PD effect on the unilateral and distal upper limb in early stage. These findings are helpful for future researches related to clinical applications and mechanisms of arm swing asymmetry in PD.     

A multidisciplinary treatment for encopresis in children with developmental disabilities

Achieving continence of one's bowel movements is a key step in development and failure to do so leads to many negative consequences. Treatments for encopresis appearing in the literature have employed behavioral strategies; medications such as suppositories, laxatives, or enemas; and in some studies a combination of these approaches. To date, attempts to extend successful treatments for encopresis in typically developing children to those with developmental disabilities have been limited. The current study included three participants diagnosed with developmental disabilities who had a history of encopresis. None of the participants had a continent bowel movement under baseline conditions. Continent bowel movements increased during treatment that included the addition of suppositories to elicit continent bowel movements. Two participants began having independent continent bowel movements (i.e., without requiring suppositories) and medication was successfully faded out for the remaining participant. Treatment took between 13 and 21 days.     

Experimental dissociations between memory measures: Influence of retrieval strategies

The objective of this study was to explore the participants’ processing strategies on the mere exposure effect, object decision priming and explicit recognition. In Experiments 1, we observed that recognition and the mere exposure effect for unfamiliar three-dimensional objects were not dissociated by plane rotations in the same way as recognition and object decision priming. However, we showed that, under identical conditions, prompting analytic (part-based) processing at testing produced a large plane rotation effect on recognition and the mere exposure effect similar to that observed for object decision priming (Experiment 2). Furthermore, inducing a non-analytic (whole-based) processing strategy at testing produced a reduced plane rotation effect on recognition and object decision (Experiments 3 and 4), similar to that observed for the mere exposure effect. These findings suggest that participants’ processing strategies influence performance on the three tasks.     

Learner Articulation as Interactional Achievement: Studying the Conversation of Gesture

Learner articulation, studied under a variety of names (e.g., self-explanation, self-directed, and generative summarization), has been shown to contribute to new learning. Whereas prior research has focused on measuring the effects of various forms of articulation on learning outcomes, this article focuses on how such articulation may be accomplished, moment to moment and turn by turn, in learning settings. It documents some of the ways in which participants use their bodies and, in particular, their hands while displaying what they know. It presents fine-grained analyses of 3 videotaped fragments of naturally occurring interaction among medical teachers and students participating in tutorial meetings in a problem-based learning curriculum. Within these 3 exhibits evidence was found of recipient design with regard to gesture production and recipient response with reference to its performance. Also found was evidence of gesture reuse as a mechanism for cohesion across turns at talk and as a display of mutual understanding. This article represents a preliminary step toward a more general program of research focusing on sense-making practices in learning settings. Extending an understanding of how such practices are accomplished interactionally is a crucial step toward eventually being able to give an adequate account of what makes any exemplary form of instruction effective.     

Strategies used for unconstrained direction change during walking

Full functional mobility requires adaptations, such as turning, to the basic straight locomotor pattern. The aim was to assess the mechanics of completing a complex turning manoeuvre. A full 3-dimensional kinematic and kinetic analysis of the ipsilateral limb was carried out during both straight gait and unconstrained turning through 90 degrees. 10 healthy university students participated. Analysis indicated that two distinctive substrategies of the spin turn-ipsilateral pivot and ipsilateral crossover-were employed. The ipsilateral pivot was the more dynamic turn and required two additional power phases at the ankle and hip to facilitate the pivot phase. The ipsilateral crossover uses a fall into the new direction. The spin turn is a more complex action than previously indicated.     

Memory for targets in a multi‐level simulated‐environment: A comparison between able‐bodied and physically disabled children

Two groups of children, one able‐bodied and the other with physical disabilities, explored a symmetrical three‐tiered virtual building that contained six distinctive target objects, two on each storey. In a subsequent test, the target objects were removed and participants were asked to make judgments of the directions to the former target locations from each floor in turn. At each test site, judgments were required for targets that were formerly on the same floor and for those on higher and lower floors. Relative tilt error scores suggested a bias for both groups, in that targets that were higher than the test location were judged as consistently lower than their actual position, whereas targets that were lower than the test location were judged as higher than their actual position. Absolute tilt errors revealed an asymmetry in both groups, with more accurate tilt errors for judgments directed to lower than higher floors. The relevance of these results for the source of the asymmetry is discussed.     

Common and specific gait patterns in people with varying anatomical levels of lower limb amputation and different prosthetic components

The present study’s aim was to identify the kinematic and kinetic gait patterns and to measure the energy consumption in people with amputation according to both the anatomical level of amputation and the type of prosthetic components in comparison with a control group matched for the gait speed. Fifteen subjects with unilateral transtibial amputation (TTA), forty with unilateral transfemoral amputation (TFA) (9 with mechanical, 17 with CLeg and 14 with Genium prosthesis) and forty healthy subjects were recruited. We computed the time-distance gait parameters; the range of angular motion (RoM) at hip, knee and ankle joints, and at the trunk and pelvis; the values of the 2 peaks of vertical force curve; the full width at half maximum (FWHM) and center of activity (CoA) of vertical force; the mechanical behavior in terms of energy recovery (R-step) and energy consumption. The main results were: i) both TTA and TFA show a common gait pattern characterized by a symmetric increase of step length, step width, double support duration, pelvic obliquity, trunk lateral bending and trunk rotation RoMs compared to control groups. They show also an asymmetric increase of stance duration and of Peak1 in non-amputated side and a decrease of ankle RoM in amputated side; ii) only TFA show a specific gait pattern, depending on the level of amputation, characterized by a symmetric reduction of R-step and an asymmetric decrease of stance duration, CoA and FWHM and an increase of Peak1 in the amputated side and of hip and knee RoM, CoA and FWHM in the non-amputated side; iii) people with amputation with Genium prosthesis show a longer step length and increased hip and knee RoMs compared to people with amputation with mechanical prosthesis who conversely show an increased pelvic obliquity: these are specific gait patterns depending of the type of prosthesis. In conclusion, we identified both common and specific gait patterns in people with amputation, either regardless of, or according to their level of amputation and the type of prosthetic component.     

Trait-Focused Spin in Presidential Debates: Surviving the Kisses of Death

In the context of presidential debates, 2 experiments explored the impact of “trait-focused spin”—messages interpreting potentially negative personality traits in terms of broader, positive frameworks—in comparison to unfocused spin—messages simply predicting positive performance. Of interest were differences between high and low Need for Cognition (NFC) participants in their willingness to accept these messages. In Experiment 1, high NFC participants responded well to trait-focused spin but found unfocused spin unpersuasive. Low NFC participants responded equally well to both. In Experiment 2, high NFC participants again rated the target candidate more positively after trait-focused but not after unfocused spin, whereas low NFC participants did the opposite. Thus trait-focused spin can influence even those suspicious of unfocused spin.     

Speech Planning at Turn Transitions in Dialog Is Associated With Increased Processing Load

Speech planning is a sophisticated process. In dialog, it regularly starts in overlap with an incoming turn by a conversation partner. We show that planning spoken responses in overlap with incoming turns is associated with higher processing load than planning in silence. In a dialogic experiment, participants took turns with a confederate describing lists of objects. The confederate’s utterances (to which participants responded) were pre‐recorded and varied in whether they ended in a verb or an object noun and whether this ending was predictable or not. We found that response planning in overlap with sentence‐final verbs evokes larger task‐evoked pupillary responses, while end predictability had no effect. This finding indicates that planning in overlap leads to higher processing load for next speakers in dialog and that next speakers do not proactively modulate the time course of their response planning based on their predictions of turn endings. The turn‐taking system exerts pressure on the language processing system by pushing speakers to plan in overlap despite the ensuing increase in processing load.     

Standard and Short RoM Isokinetic Testing: Comparative Analysis in Identifying Submaximal Shoulder External Rotator Effort

An isokinetic-related parameter termed the difference between eccentric-concentric strength ratios at two distinct test velocities (DEC) based on 60° (standard) range of motion (RoM) has been proven to be highly efficient detecting feigned muscular efforts. This study aimed to verify whether a DEC derived from a much shorter test RoM (20°) was equally useful than a long RoM–derived one. Eighteen healthy men (32.4 ± 6.4 years old) took part in a study focusing on shoulder external rotation isokinetic strength. Participants performed a genuine shoulder external rotator maximal effort (eight pairs of concentric and eccentric contractions at high and low velocities at short and long RoM) and then instructed to feign maximal effort. Contraction velocities were adjusted accordingly by applying a 1:4 gradient and peak moments registered. Both condition DEC was then calculated by subtracting the eccentric and concentric strength ratios at low velocities from those at high velocities. DEC scores in the feigned effort were significantly higher than maximal effort ones in both conditions in men. It enabled the setting of specific cutoff levels for separating the efforts. Both approaches revealed a coincident sensitivity (78%) whereas short RoM showed an even higher specificity: 88% versus 78%. Thus, the short RoM protocol provides clinically acceptable detection power.     

“Tower,Am I Cleared to Land?”: Problematic Communication in Aviation Discourse

This study examined problematic communication in pilot–air traffic controller (ATC) interaction. More than 15 hours of pilot–ATC dialogue were collected by monitoring control tower frequencies at 15 U.S. airports. The transcribed data yielded a total of 34 ATCs, 270 pilots, and 1,799 turns of talk. Analyses revealed that (a) communication problematics manifested in pilot turns more than ATC turns, (b) higher amounts of information led to increased problematic communication in the subsequent turn, and (c) linguistic violations of ATC protocol increased problematic communication in the subsequent turn. Partial support was found for the effect of frequency congestion on problematic communication. No effect was observed for airport size on problematic communication. The discussion addresses the significance of protocol deviations and system constraints for problematic communication. Applications for the findings in pilot–ATC radio interaction are also suggested.     

Specificity and variability of trunk kinematics on a mechanical horse

As perturbation training is gaining popularity, it is important to better understand postural control during complex three-dimensional stimuli. One clinically relevant and commonly used three-dimensional stimulus is found in hippotherapy and simulated hippotherapy on a mechanical horse. We tested nine healthy participants on a horse simulator, measured head and trunk kinematics, and characterized data in time (root-mean-square and variability) and frequency (amplitude spectra, gains, and phases) domains. We addressed three fundamental questions: 1) What is the specificity of postural responses to the simulator? 2) Which plane of motion is associated with the most and least variability (repeatable movements across repeated stimuli and across participants)? 3) To what extent are postural responses influenced by different degrees of stability (addition of pelvis straps and trunk support)? We found head and trunk responses were highly specific to the three-dimensional simulator perturbation direction and frequency. Frontal plane responses had the least variability across repetitions and participants whereas transverse motion was most variable. Head motion was more variable than the trunk at low frequencies and exhibited a marked decrease in tilt in the sagittal plane. Finally, the inclusion of pelvis straps had minimal effect on kinematics at low frequencies but altered higher frequencies; whereas added trunk support reduced head and trunk responses to perturbations and altered timing characteristics in all three planes. In conclusion, the present study suggests that frontal plane motion was under a high level of control, and results support the idea that specific head and trunk postural responses can be elicited from a complex three-dimensional stimuli, such as those found in hippotherapy. Researchers and clinicians can use results from this study to help interpret variability, implement mechanical adjustments to stability, and assess responses in pathological populations.     

Stability and variability of affective experience and interpersonal behavior in borderline personality disorder

This study examined both mean levels and intraindividual variability in the mood and interpersonal behavior of individuals with borderline personality disorder (BPD) and nonclinical control participants over a 20-day event-contingent recording period. Individuals in the BPD group experienced more unpleasantly valenced affect and were less dominant, more submissive, more quarrelsome, and more extreme in overall levels of behavior than control participants. In addition to these mean-level differences, individuals with BPD also reported more intraindividual variability in overall affect valence and in pleasantly valenced affect; displayed greater variability in dominant, quarrelsome, and agreeable behaviors; and exhibited an increased tendency to "spin" among interpersonal behaviors relative to nonclinical control participants. The findings document behavioral and affective manifestations of BPD in the context of naturally occurring interpersonal situations.