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Biomedical subjects

Andrew D Wilson

Publications and source records attributed to Andrew D Wilson.

6 recordsLinked to original sources
PubMed2006

Methodological issues in measures of imitative reaction times.

Ideomotor (IM) theory suggests that observing someone else perform an action activates an internal motor representation of that behaviour within the observer. Evidence supporting the case for an ideomotor theory of imitation has come from studies that show imitative responses to be faster than the same behavioural measures performed in response to spatial cues. In an attempt to replicate these findings, we manipulated the salience of the visual cue and found that we could reverse the advantage of the imitative cue over the spatial cue. We suggest that participants utilised a simple visuomotor mechanism to perform all aspects of this task, with performance being driven by the relative visual salience of the stimuli. Imitation is a more complex motor skill that would constitute an inefficient strategy for rapid performance.

Adult↗
PubMed2005

Human movement coordination implicates relative direction as the information for relative phase.

The current studies explore the informational basis of the coupling in human rhythmic movement coordination tasks. Movement stability in these tasks is an asymmetric U-shaped function of mean relative phase; 0 degrees is maximally stable, 90 degrees is maximally unstable and 180 degrees is intermediate. Bingham (2001, 2004a, 2004b) hypothesized that the information used to perform coordinated rhythmic movement is the relative direction of movement, the resolution of which is determined by relative speed. We used an experimental paradigm that entails using a circular movement to produce a linear motion of a dot on a screen, which must then be coordinated with a linearly moving computer controlled dot. This adds a component to the movement that is orthogonal to the display. Relative direction is not uniquely defined between orthogonal components of motion, but relative speed is; it was therefore predicted that the addition of the component would only introduce a symmetric noise component and not otherwise contribute to the U-shape structure of movement stability. Results for experiment 1 supported the hypothesis; movement that involved the additional component was overall less stable than movement that involved only the parallel component along which relative direction can be defined. Two additional studies ruled out alternative explanations for the pattern of data in experiment 1. Overall, the results strongly implicate relative direction as the information underlying performance in rhythmic movement coordination tasks.

Adult↗
PubMed2005

Perceptual coupling in rhythmic movement coordination: stable perception leads to stable action.

Rhythmic movement coordination exhibits characteristic patterns of stability, specifically that movements at 0 degrees mean relative phase are maximally stable, 180 degrees is stable but less so than 0 degrees, and other coordinations are unstable without training. Recent research has demonstrated a role for perception in creating this pattern; perceptual variability judgments covary with movement variability results. This suggests that the movement results could be due in part to differential perceptual resolution of the target movement coordinations. The current study used a paradigm that enabled simultaneous access to both perception (between-trial) and movement (within-trial) stability measures. A visually specified 0 degrees target mean relative phase enabled participants to produce stable movements when the movements were at a non-0 degrees relationship to the target being tracked. Strong relationships were found between within-trial stability (the traditional movement measure) and between-trial stability (the traditional perceptual judgment measure), suggestive of a role for perception in producing coordination stability phenomena. The stabilization was incomplete, however, indicating that visual perception was not the sole determinant of movement stability. Rhythmic movement coordination is intrinsically a perception/action system.

Adolescent↗
PubMed2003

Proprioceptive perception of phase variability.

Previous work has established that judgments of relative phase variability of 2 visually presented oscillators covary with mean relative phase. Ninety degrees is judged to be more variable than 0 degrees or 180 degrees, independently of the actual level of phase variability. Judged levels of variability also increase at 180 degrees. This pattern of judgments matches the pattern of movement coordination results. Here, participants judged the phase variability of their own finger movements, which they generated by actively tracking a manipulandum moving at 0 degrees, 90 degrees, or 180 degrees, and with 1 of 4 levels of Phase Variability. Judgments covaried as an inverted U-shaped function of mean relative phase. With an increase in frequency, 180 degrees was judged more variable whereas 0 degrees was not. Higher frequency also reduced discrimination of the levels of Phase Variability. This matching of the proprioceptive and visual results, and of both to movement results, supports the hypothesized role of online perception in the coupling of limb movements. Differences in the 2 cases are discussed as due primarily to the different sensitivities of the systems to the information.

Adolescent↗
PubMed2002

The natural history of acute cough in children aged 0 to 4 years in primary care: a systematic review.

Professional and parental uncertainty regarding the natural history of cough and respiratory tract infection (R77) in pre-school children may in part be responsible for the high consultation, reconsultation, and antibiotic prescribing rates in this age group. The aim of the study was to review the evidence about the natural history of acute cough in children aged between 0 and 4 years presenting to primary care in terms of illness duration and complications. The study was a systematic review, with qualitative and quantitative data synthesis, of control and placebo arms of systematic reviews, randomised controlled trials (RCTs), and cohort studies set in primary care. Searches were done of MEDLINE (between 1966 and June 1998), EMBASE (between 1988 and September 1998), and the Cochrane Library databases, using the MeSH terms 'respiratory tract infection, 'cough, and 'bronchitis, and the textwords 'cough' 'bronchitis, and 'chest infection, limited to children aged between 0 and 4years, and English language articles. Eight RCTs and two cohort studies met the review criteria. At one week, 75% of children may have improved but 50% may be still coughing and/or have a nasal discharge. At two weeks up to 24% of children may be no better. Within two weeks of presentation, 12% of children may experience one or more complication, such as rash, painful ears, diarrhoea, vomiting, or progression to bronchitis/pneumonia. This review offers parents and clinicians more prognostic information about acute cough in pre-school children. Illness duration may be longer and complications higher than many parents and clinicians expect. This may help to set more realistic expectations of the illness and help parents to decide when and if to reconsult. This information may be useful to those designing patient information and self-help resources.

Acute Disease↗