Patients suffering from nonspecific work-related upper extremity disorders exhibit insufficient movement strategies

The purpose of this research was to investigate whether patients experiencing nonspecific complaints of the forearm caused by sustained use of the personal computer exhibit deviant movement strategies as compared to healthy participants. Patients (N=10) and controls (N=24) performed a graphical aiming task combined with an auditory memory task. Force production (pen pressure), kinematic- and performance variables were recorded. During a trial, the control group gradually increased pen pressure from the stationary phases to the dynamic phase. The patients increased their pen pressure much more abruptly and to such a degree that the final pressure during real-time movement far exceeded that of the controls. Memory load led to a greater increase of pen pressure from the stationary phase to the dynamic phase in the patient group. Patients further displayed longer reaction times. The results are discussed within the framework of our recent theory on the role of neuromotor noise in the regulation of task performance under conditions of stress.     

Driving and riding avoidance following motor vehicle crashes in a non-clinical sample: psychometric properties of a new measure

Three studies were conducted to assess the reliability and validity of a measure that we developed using a non-clinical sample of university undergraduates, the Driving and Riding Avoidance Scale (DRAS). Study 1 indicated that the scale was internally consistent (α=0.92) and that a four-factor model (general avoidance, avoidance of traffic and busy roads, avoidance of weather or darkness, and riding avoidance) provided the best fit to the data in a sample of 386 crash survivors. This study also revealed that survivors who received medical treatment for their crash-related injuries reported significantly greater avoidance than people who were uninjured or injured and not medically treated. Study 2 revealed that the DRAS possessed acceptable test-retest reliability (r=0.83) over a 4-week interval in a sample of 67 crash survivors. Using a sample of 118 survivors, study 3 examined the instrument’s convergent and divergent validity through correlations with the Accident Fear Questionnaire (AFQ), the Mobility Inventory (MI), the Fear Survey Schedule-II (FSS-II), and the Fear Questionnaire (FQ). The strongest relationships were observed between the DRAS and the AFQ and with a driving subscale created from the MI items. The DRAS exhibited significantly weaker relationships with the FQ subscales that assessed other kinds of phobic avoidance.     

The role of crawling and walking experience in infant spatial memory

This research explored infants' use of place learning and cue learning in a locomotor task across the transition from crawling to walking. Novice and expert crawling and walking infants were observed in a novel locomotor task-finding a hidden goal location in a large space. In Experiment 1, infants were tested with distal landmarks. Infants with fewer than 6 weeks of experience, either crawling or walking, could not find the goal location. All infants with more locomotor experience were more successful. Learning did not transfer across the transition to walking. In Experiment 2, novice and expert crawlers and walkers were tested with a direct landmark. Again, novice crawlers and walkers with fewer than 6 weeks of experience could not find the goal, whereas those with more experience could. Taken together, these findings suggest that infants' spatial learning is inextricably linked to mode of locomotion.     

The effects of meaningful irrelevant speech and road traffic noise on teachers' attention, episodic and semantic memory

The aim of the present experiment was to examine the effects of meaningful irrelevant speech and road traffic noise on attention, episodic and semantic memory, and also to examine whether the noise effects were age-dependent. A total of 96 male and female teachers in the age range of 35-45 and 55-65 years were randomly assigned to a silent or the two noise conditions. Noise effects found in episodic memory were limited to a meaningful text, where cued recall contrary to expectations was equally impaired by the two types of noise. However, meaningful irrelevant speech also deteriorated recognition of the text, whereas road traffic noise caused no decrement. Retrieval from two word fluency tests in semantic memory showed strong effects of noise exposure, one affected by meaningful irrelevant speech and the other by road traffic noise. The results implied that both acoustic variation and the semantic interference could be of importance for noise impairments. The expected age-dependent noise effects did not show up.     

Gaze characteristics of elite and near-elite athletes in ice hockey defensive tactics

Traditional visual search experiments, where the researcher pre-selects video-based scenes for the participant to respond to, shows that elite players make more efficient decisions than non-elites, but disagree on how they temporally regulate their gaze. Using the vision-in-action [J.N. Vickers, J. Exp. Psychol.: Human Percept. Perform. 22 (1996) 342] approach, we tested whether the significant gaze that differentiates elite and non-elite athletes occurred either: early in the task and was of more rapid duration [A.M. Williams et al., Res. Quart. Exer. Sport 65 (1994) 127; A.M. Williams and K. Davids, Res. Quart. Exer. Sport 69 (1998) 111], or late in the task and was of longer duration [W. Helsen, J.M. Pauwels, A cognitive approach to visual search in sport, in: D. Brogan, K. Carr (Eds.), Visual Search, vol. II, Taylor and Francis, London, 1992], or whether a more complex gaze control strategy was used that consisted of both early and rapid fixations followed by a late fixation of long duration prior to the final execution. We tested this using a live defensive zone task in ice hockey. Results indicated that athletes temporally regulated their gaze using two different gaze control strategies. First, fixation/tracking (F/T) gaze early in the trial were significantly shorter than the final F/T and confirmed that the elite group fixated the tactical locations more rapidly than the non-elite on successful plays. And secondly, the final F/T prior to critical movement initiation (i.e. F/T-1) was significantly longer for both groups, averaging 30% of the final part of the phase and occurred as the athletes isolated a single object or location to end the play. The results imply that expertise in defensive tactics is defined by a cascade of F/T, which began with the athletes fixating or tracking specific locations for short durations at the beginning of the play, and concluded with a final gaze of long duration to a relatively stable target at the end. The results are discussed within the context of gaze research in open and closed skills, as well as theoretical models of long-term memory and decision making in sport.     

Clinical and anatomical correlates of apraxia of speech

In a previous study (Dronkers, 1996), stroke patients identified as having apraxia of speech (AOS), an articulatory disorder, were found to have damage to the left superior precentral gyrus of the insula (SPGI). The present study sought (1) to characterize the performance of patients with AOS on a classic motor speech evaluation, and (2) to examine whether severity of AOS was influenced by the extent of the lesion. Videotaped speech evaluations of stroke patients with and without AOS were reviewed by two speech-language pathologists and independently scored. Results indicated that patients with AOS made the most errors on tasks requiring the coordination of complex, but not simple, articulatory movements. Patients scored lowest on the repetition of multisyllabic words and sentences that required immediate shifting between place and manner of articulation and rapid coordination of the lips, tongue, velum, and larynx. Last, all patients with AOS had lesions in the SPGI, whereas patients without apraxia of speech did not. Additional involvement of neighboring brain areas was associated with more severe forms of both AOS as well as language deficits, such as aphasia.     

Effects of iron deficiency in infancy on patterns of motor development over time

This longitudinal study of the effects of iron deficiency in infancy assessed motor development over time in 185 healthy Costa Rican children who varied in iron status at 12-23 months. Longitudinal analyses (hierarchical linear modeling) used the Bayley Psychomotor Index before and both 1 week and 3 months after iron treatment in infancy and the Bruninks-Oseretsky Test of Motor Proficiency - long form at 5 years and short form at 11-14 years. Children with chronic severe iron deficiency in infancy had lower motor scores at the beginning of the study and a lower but parallel trajectory for motor scores through early adolescence. Thus, there was no evidence of catch-up in motor development, despite iron therapy in infancy that corrected iron deficiency anemia in all cases.     

Different types of environmental enrichment have discrepant effects on spatial memory and synaptophysin levels in female mice

Environmental enrichment paradigms that incorporate cognitive stimulation, exercise, and motor learning benefit memory and synaptic plasticity across the rodent lifespan. However, the contribution each individual element of the enriched environment makes to enhancing memory and synaptic plasticity has yet to be delineated. Therefore, the current study tested the effects of three of these elements on memory and synaptic protein levels. Young female C57BL/6 mice were given 3h of daily exposure to either rodent toys (cognitive stimulation) or running wheels (exercise), or daily acrobatic training for 6 weeks prior to and throughout behavioral testing. Controls were group housed, but did not receive enrichment. Spatial working and reference memory were tested in a water-escape motivated radial arm maze. Levels of the presynaptic protein synaptophysin were then measured in frontoparietal cortex, hippocampus, striatum, and cerebellum. Exercise, but not cognitive stimulation or acrobat training, improved spatial working memory relative to controls, despite the fact that both exercise and cognitive stimulation increased synaptophysin levels in the neocortex and hippocampus. These data suggest that exercise alone is sufficient to improve working memory, and that enrichment-induced increases in synaptophysin levels may not be sufficient to improve working memory in young females. Spatial reference memory was unaffected by enrichment. Acrobat training had no effect on memory or synaptophysin levels, suggesting a minimal contribution of motor learning to the mnemonic and neuronal benefits of enrichment. These results provide the first evidence that different elements of the enriched environment have markedly distinct effects on spatial memory and synaptic alterations.     

Work potential of road accident survivors with post-traumatic stress disorder

Work potential in adult survivors of road accidents with and without post-traumatic stress disorder (PTSD) was examined at a mean of 8.6 months (SD = 3.77) post-accident. All participants were working prior to their accident. Results showed that survivors with PTSD had significantly less work potential post-accident than survivors without PTSD. Specific barriers to employability for survivors with PTSD identified by this study included high levels of depression, reduced time-management ability, and an over-concern or anxiety with physical injuries. Respondents with PTSD, however, reported significantly greater extrinsic motivation to work than those without PTSD. Early intervention and referral to occupational rehabilitation programs that: (1) help address these barriers to employability and stimulate the existing motivation to return to work, and (2) work alongside clinical treatment programs, may assist in the reduction of poor work outcomes that people with PTSD following road accidents often experience.     

Interference effects demonstrate distinct roles for visual and motor imagery during the mental representation of human action

Four experiments were completed to characterize the utilization of visual imagery and motor imagery during the mental representation of human action. In Experiment 1, movement time functions for a motor imagery human locomotion task conformed to a speed-accuracy trade-off similar to Fitts' Law, whereas those for a visual imagery object motion task did not. However, modality-specific interference effects in Experiment 2 demonstrate visual and motor imagery as cooperative processes when the action represented is tied to visual coordinates in space. Biomechanic-specific motor interference effects found in Experiment 3 suggest one basis for separation of processing channels within motor imagery. Finally, in Experiment 4 representations of motor actions were found to be generated using only visual imagery under certain circumstances: namely, when the imaginer represented the motor action of another individual while placed at an opposing viewpoint. These results suggest that the modality of representation recruited to generate images of human action is dependent on the dynamic relationship between the individual, movement, and environment.