An EEG study of mental rotation-related negativity in children with Developmental Coordination Disorder.
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Adult↗
Biomedical subjects
P H Wilson
Publications and source records attributed to P H Wilson.
Motor, visual and egocentric transformations in children with Developmental Coordination Disorder.
AIM: This study aimed to test the internal modelling deficit (IMD) hypothesis using the mental rotation paradigm. BACKGROUND: According to the IMD hypothesis, children with Developmental Coordination Disorder (DCD) have an impaired ability to internally represent action. Thirty-six children (18 DCD) completed four tasks: two versions of a single-hand rotation task (with and without explicit imagery instructions), a whole-body imagery task and an alphanumeric rotation task. RESULTS: There was partial support for the hypothesis that children with DCD would display an atypical pattern of performance on the hand rotation task, requiring implicit use of motor imagery. Overall, there were no significant differences between the DCD and control groups when the hand task was completed without explicit instructions, on either response time or accuracy. However, when imagery instructions were introduced, the controls were significantly more accurate than the DCD group, indicating that children with DCD were unable to benefit from explicit cuing. As predicted, the controls were also significantly more accurate than the DCD group on the whole-body task, with the accuracy of the DCD group barely rising above chance. Finally, and as expected, there was no difference between the groups on the alphanumeric task, a measure of visual (or object-related) imagery. CONCLUSIONS: The inability of the DCD group to utilize specific motor imagery instructions and to perform egocentric transformations lends some support to the IMD hypothesis. Future work needs to address the question of whether the IMD itself is subgroup-specific.
Analysis of Variance↗
Internal representation of movement in children with developmental coordination disorder: a mental rotation task.
Recent studies show that children with developmental coordination disorder (DCD) have difficulties in generating an accurate visuospatial representation of an intended action, which are shown by deficits in motor imagery. This study sought to test this hypothesis further using a mental rotation paradigm. It was predicted that children with DCD would not conform to the typical pattern of responding when required to imagine movement of their limbs. Participants included 16 children with DCD and 18 control children; mean age for the DCD group was 10 years 4 months, and for controls 10 years. The task required children to judge the handedness of single-hand images that were presented at angles between 0 degrees and 180 degrees at 45 degrees intervals in either direction. Results were broadly consistent with the hypothesis above. Responses of the control children conformed to the typical pattern of mental rotation: a moderate trade-off between response time and angle of rotation. The response pattern for the DCD group was less typical, with a small trade-off function. Response accuracy did not differ between groups. It was suggested that children with DCD, unlike controls, do not automatically enlist motor imagery when performing mental rotation, but rely on an alternative object-based strategy that preserves speed and accuracy. This occurs because these children manifest a reduced ability to make imagined transformations from an egocentric or first-person perspective.
Child↗
Genotypic and phenotypic studies of murine intestinal lactobacilli: species differences in mice with and without colitis.
Lactobacilli represent components of the commensal mammalian gastrointestinal microbiota and are useful as probiotics, functional foods, and dairy products. This study includes systematic polyphasic analyses of murine intestinal Lactobacillus isolates and correlation of taxonomic findings with data from cytokine production assays. Lactobacilli were recovered from mice with microbiota-dependent colitis (interleukin-10 [IL-10]-deficient C57BL/6 mice) and from mice without colitis (Swiss Webster and inducible nitric oxide synthetase-deficient C57BL/6 mice). Polyphasic analyses were performed to elucidate taxonomic relationships among 88 reference and murine gastrointestinal lactobacilli. Genotypic tests included single-locus analyses (16S ribosomal DNA sequencing and 16S-23S rRNA intergenic spacer region PCR) and genomic DNA profiling (repetitive DNA element-based PCR), and phenotypic analyses encompassed more than 50 tests for carbohydrate utilization, enzyme production, and antimicrobial resistance. From 20 mice without colitis, six Lactobacillus species were recovered; the majority of the mice were colonized with L. reuteri or L. murinus (72% of isolates). In contrast, only, L. johnsonii was isolated from 14 IL-10-deficient mice. Using an in vitro assay, we screened murine isolates for their ability to inhibit tumor necrosis factor alpha (TNF-alpha) secretion by lipopolysaccharide-activated macrophages. Interestingly, a subpopulation of lactobacilli recovered from mice without colitis displayed TNF-alpha inhibitory properties, whereas none of the L. johnsonii isolates from IL-10-deficient mice exhibited this effect. We propose that differences among intestinal Lactobacillus populations in mammals, combined with host genetic susceptibilities, may account partly for variations in host mucosal responses.
Animals↗
Fine motor deficiencies in children with developmental coordination disorder and learning disabilities: an underlying open-loop control deficit.
Thirty-two children with Developmental Coordination Disorder (DCD) and learning disabilities (LD) and their age-matched controls attending normal primary schools were investigated using kinematic movement analysis of fine-motor performance. Three hypotheses about the nature of the motor deficits observed in children with LD were tested: general slowness hypothesis, limited information capacity hypothesis, and the motor control mode hypothesis. Measures of drawing movements were analyzed under different task conditions using a Fitts' paradigm. In a reciprocal aiming task, the children drew straight-line segments between two targets 2.5 cm apart. Three Target Sizes were used (0.22, 0.44, and 0.88 cm). Children used an electronic pen that left no trace on the writing tablet. To manipulate the degree of open-loop movement control, the aiming task was performed under two different control regimes: discrete aiming and cyclic aiming. The kinematic analysis of the writing movements of the 32 children with DCD/LD that took part in the experimental study confirmed that besides learning disabilities they have a motor learning problem as well. Overall, the two groups did not differ in response time, nor did they respond differently according to Fitts' Law. Both groups displayed a conventional trade-off between Target Size and average Movement Time. However, while movement errors for children with DCD/LD were minimal on the discrete task, they made significantly more errors on the cyclic task. This, together with faster endpoint velocities, suggests a reduced ability to use a control strategy that emphasizes the terminal control of accuracy. Taken together, the results suggest that children with DCD/LD rely more on feedback during movement execution and have difficulty switching to a feedforward or open-loop strategy.
Biomechanical Phenomena↗
The ability to execute saccades on the basis of efference copy: impairments in double-step saccade performance in children with developmental co-ordination disorder.
The double-step saccade task (DSST) was used to test the hypothesis that children with developmental co-ordination disorder (DCD) who experience deficits in motor imagery have difficulty processing the visual spatial consequences of intended movements using efference copy signals. In order to ensure that the second saccade in the DSST was executed in the absence of visual cues and had to be programmed on the basis of extra-retinal information (efference copy), we analysed only those double-step ensembles where latency plus duration of first saccades was greater than 240 ms (total presentation time of the targets). No significant differences between DCD and control children were evident on measures of latency of first saccades, intersaccadic interval and first saccade error. As predicted, children with DCD who have impaired motor imagery demonstrated specific deficits on the DSST where efference copy had been used to program the saccade sequence. More specifically, these children were less accurate in terms of final eye position on second saccades. Our results raise the possibility that abnormalities in the processing of efference copy signals could underlie motor clumsiness in the majority of children with DCD. Furthermore, the origin of this deficit in efference copy probably exists at the level of the parietal lobe.
Child↗
Abnormalities of motor and praxis imagery in children with DCD.
In an earlier study using the visually guided pointing task (VGPT) the authors showed that the timing of imagined movement sequences in children with developmental coordination disorder (DCD) does not conform to the conventional speed-for-accuracy trade-off (or Fitts' law [P.M. Fitts, Journal of Experimental Psychology 47 (1954) 381-391]) that occurs when the distance and accuracy requirements of movements are varied [P. Maruff, P.H. Wilson, M. Trebilcock, J. Currie, Neuropsychologia 37 (1999b) 1317-1324]. The present study sought to replicate this earlier finding and to examine (using a weight manipulation) whether this deficit was also attributable to inaccurate programming of relative force. The chronometry of real and imagined movements was investigated in a group of 20 children with DCD aged between 8 and 12 years and a group of controls matched on age and verbal IQ (VIQ). Movement duration was tested for real and imagined movements using the preferred hand, with the VGPT performed under two load conditions: with and without the addition of a weight attached to a pen. Group means of each subjects' mean movement duration were calculated and plotted against target width for each of the four conditions [Movement type (2) x Load (2)] and a logarithmic curve was fitted to the data points. In the control group, the speed-for-accuracy trade-off for both real and imagined performance conformed to Fitts' law under each load condition. In the DCD group only real movements conformed to Fitts' law. Moreover, the effect of load differed between groups--for real movements, movement duration did not differ between load and no-load conditions for either group, while for imagined movements, movement duration increased under the load condition for the control group only. These results replicate and extend the results of our earlier study. This pattern of performance suggests that children with DCD have an impairment in the ability to generate internal representations of volitional movements which may reflect an impaired ability to process efference copy signals. The ability to programme both relative force and timing appears to underly this difficulty. Results have implications for the use of (guided) motor imagery training in order to facilitate the development of motor skill in children with DCD.
Child↗
Bannayan-Riley-Ruvalcaba syndrome: report of a family.
Bannayan-Riley-Ruvalcaba (BRR) syndrome is a rare inherited condition. We describe the protean orofacial manifestations of this syndrome in one family and consider their management. The dental surgeon should be aware of this entity, its orofacial connotations and the possible association with Cowden's syndrome.
Abnormalities, Multiple↗
Development of the psychological impact of tinnitus interview: a clinician-administered measure of tinnitus-related distress.
The development of valid and reliable methods for assessing psychological aspects of tinnitus continues to be an important goal of research. Such assessment methods are potentially useful in clinical and research contexts. Existing self-report measures have a number of disadvantages, and so a need exists to develop a form of assessment that is less open to response bias and the effects of experimental demand. A new approach, the Psychological Impact of Tinnitus Interview (PITI), is described, and some preliminary data on its psychometric properties are reported. The results suggest that the PITI is capable of providing a measure of separate, relatively independent dimensions of tinnitus-related distress--namely, sleep difficulties, general distress, mood, suicidal aspects, and avoidance of or interference with normal activities. This method may lead to more refined measures of these dimensions of tinnitus-related psychological difficulties. The PITI should be regarded as a promising assessment tool for use in experimental settings, pending further work on its content, coding method, and administration.
Humans↗
Asymmetries between dominant and non-dominant hands in real and imagined motor task performance.
Motor imagery is a dynamic state in which an individual mentally simulates the performance of a specific motor action or motor task. Recent behavioural and neuroimaging evidence suggests that the same neurocognitive networks control real and imagined movements. This hypothesis was tested by investigating whether motor asymmetries related to cerebral dominance also occurred for imagined movements. Fifty subjects performed the visually guided pointing task of Sirigu et al. [Sirigu, A., Duhamel, J., Cohen, L., Pillon, B., Dubois, B. and Agid, Y., The mental representation of hand movements after parietal cortex damage. Science, 1996, 273, 1564-1567.] using their dominant and non-dominant hands. Analysis of group data indicated that both real and imagined movement conformed to Fitts' law. Analysis of individual data indicated that asymmetries arising from motor dominance in real movements also occurred for imagined movements. However, the relative slowing and error associated with the non-dominant hand was greater for imagined movements than for real movements. These asymmetries support the hypothesis that real and imagined movements are represented within the same neurocognitive networks but suggest that asymmetries in performance related to handedness are greater for imagined movements. In addition, while the visually guided pointing task provides a useful test of the ability to make imagined movements, asymmetries in the speed and reliability of imagined performance are significantly greater than those for real performance.
Adolescent↗
Isolation of Lautropia mirabilis from oral cavities of human immunodeficiency virus-infected children.
Lautropia mirabilis, a pleomorphic, motile, gram-negative coccus, has been isolated from the oral cavities of 32 of 60 (53.3%) children infected with human immunodeficiency virus (HIV) and 3 of 25 (12.0%) HIV-uninfected controls; the association of L. mirabilis isolation with HIV infection is significant (P < 0.001). All children in the study, both HIV-infected children and controls, were born to HIV-infected mothers. The presence of this bacterium was not associated with clinical disease in these children. The HIV-infected children with L. mirabilis did not differ from the HIV-infected children without L. mirabilis in immunological status, clinical status, or systemic medications. The role of HIV infection itself or concomitant factors in the establishment of L. mirabilis in the oral cavity remains to be elucidated.
Child↗
A critical analysis of directive counselling as a component of tinnitus retraining therapy.
Tinnitus retraining therapy (TRT) has been presented as a new approach to tinnitus management. In this paper a number of theoretical and practical problems with TRT are identified. These problems relate to the distinction between directive counselling and cognitive therapy, the adequacy of the cognitive therapy components, the nature of the outcome data which have been presented to date, the theoretical basis for the treatment, and the conceptual clarity of terms such as perception, attention and coping. The stated goal of removal of the perception of tinnitus may lead to confusion about the likely outcome of TRT for most patients. Methodological limitations in the research which has been published to date preclude any claims about the efficacy of TRT at the present time. It is suggested that randomized, controlled studies which include no-treatment and placebo conditions need to be undertaken. Studies are required in which the efficacy of the counselling and white noise components can be clearly isolated. Suggestions are made about the role of psychologists and non-psychologists in the provision of counselling and cognitive therapy services to tinnitus patients.
Adaptation, Psychological↗
Information processing deficits associated with developmental coordination disorder: a meta-analysis of research findings.
A meta-analysis was conducted to identify information processing factors that characterise children with Developmental Coordination Disorder (DCD). A total of 50 studies yielded 374 effect sizes based on 983 DCD and 987 control children. A mild generalised performance deficit was indicated, since motor-impaired children were inferior on almost all measures of information processing. There were, however, several areas where their deficiencies were more pronounced. The greatest deficiency was in visual-spatial processing. This was evident regardless of whether or not the tasks involved a motor component. Most other deficiencies were in the small-to-moderate range and included kinaesthetic and cross-modal processing. The findings support the notion that perceptual problems, particularly in the visual modality, are associated with difficulties in motor coordination.
Child↗
Covert orienting of visuospatial attention in children with developmental coordination disorder.
It is still unclear whether impairments in visuospatial processing in children with developmental coordination disorder (DCD) are a consequence of their motor deficits or are independent of them. In two experiments, 20 children with DCD and 20 matched controls were tested on the covert orienting of a visuospatial attention task (COVAT). Experiment 1 used a COVAT with peripheral cues and an 80% probability that targets would appear at the cued location. While the results suggested a deficit in the disengage operation of orienting covert attention for the DCD group, they were difficult to reconcile with models of covert orienting and the results of past research. Experiment 2 tested subjects on two new versions of the COVAT: the first used peripheral cues and no probability information (exogenous mode), and the second used central cues and an 80% probability that targets would appear at the cued location (endogenous mode). The DCD group displayed attentional orienting deficits only for the endogenous mode. These results suggest that impairments in the endogenous control of visuospatial attention are independent of motor deficits in DCD.
Attention↗
Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of human parotid salivary proteins: comparison of dansylation, coomassie blue R-250 and silver detection methods.
Detection of human parotid salivary proteins by dansylation and UV-transillumination after sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) has been compared with Coomassie Blue R-250 and silver staining procedures. Dansylation gives superior results in terms of both resolution and sensitivity, especially with basic proline-rich proteins (PRPs).
Dansyl Compounds↗
Prediction of adherence and control in diabetes.
This study aims to predict adherence to diabetic treatment regimens and sustained diabetic control. During two clinic visits that were 2 months apart, 63 adult outpatients completed measures of diabetic history, current treatment, diabetic control, adherence, and self-efficacy about adherence to treatment. Results showed that self-efficacy was a significant predictor of later adherence to diabetes treatment even after past levels of adherence were taken into account. Posttest levels of adherence in turn were significantly associated with posttest %HbA1c after control for illness severity. A stepwise multiple regression to predict %HbA1c at post entered pretest measures of diabetic control, treatment type, and self-efficacy, which together predicted 50% of the variance. Results are related to self-efficacy theory and implications for practice are discussed.
Adaptation, Psychological↗
Operant-behavioural and cognitive-behavioural treatment for chronic low back pain.
Fifty-eight outpatients with chronic low back pain were randomly allocated to one of six experimental conditions. Four conditions were designated as treatment conditions and two as control conditions. The four treatment groups consisted of: cognitive treatment (either with or without relaxation training) and behavioural treatment (either with or without relaxation training). The cognitive and behavioural groups also received physiotherapy. The two control conditions consisted of: attention (physiotherapy plus discussion sessions) and no-attention (physiotherapy-only) conditions. All conditions, including the two controls, received the same physiotherapy back-education and exercise program. For the sample as a whole, improvements were obtained on measures of affective distress, functional impairment, medication use, pain-related dysfunctional cognitions and use of active coping strategies. These improvements were generally maintained at 6- and 12-month follow-ups. The combined psychological/physiotherapy treatment conditions improved significantly more than the physiotherapy-only conditions from pre to posttreatment on measures of pain intensity, self-rated functional impairment and pain-related dysfunctional cognitions. However, these differences were only weakly maintained at 6- and 12-month follow-ups. The behavioural conditions improved significantly more than the cognitive conditions from pre to posttreatment on the self-rated measure of functional impairment, but this difference was not maintained at 6- and 12-month follow-ups. Progressive relaxation training was found to make little contribution to either cognitive or behavioural treatments.
Adult↗