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PubMed1991

Alcohol-related efficiency deficits using an ecologically valid test.

This study investigated whether male and female alcoholics and controls differed in their ability to solve an ecologically valid measure of abstraction. Ninety-one alcoholics (39 females, 52 males) and 61 community controls (36 females, 26 males) completed a battery of abstraction tasks including a Piagetian-type task, the Plant Task. The Plant Task demands that subjects predict the outcome of an unseen plant given a specific treatment regime. No group differences in the ability to correctly predict the unseen plant's outcome were obtained. Alcoholics were significantly poorer than controls in isolating the relevant variable (chi 2 (1) = 8.24, p = 0.004). There were no sex differences in the ability to isolate the relevant variable. However, there was a sex effect in the number of irrelevant explanations (chi 2 (3) = 15.58, p = 0.001) with females producing more than males and female alcoholics more than any of the other three cells. These data suggest that (1) alcoholics may exhibit subtle abstraction deficits most readily observed in tasks examining process as opposed to final performance, (2) males and females differ in their response patterns regarding irrelevant material, and (3) further empirical study of the Plant Task may support its use in experimental and clinical settings.

Adult↗

PubMed1999

Units of analysis in nonword reading: evidence from children and adults.

Four experiments examined variations in children's (chronological age range: 5 years 7 months to 9 years 10 months) and adults' reading strategy as a function of task demands. Experiment 1 found that less skilled readers (mean reading age: 8 years 8 months), though able to make use of rime-based spelling-to-sound correspondences (reading "by analogy"), predominantly used simple grapheme-phoneme-level correspondences in reading isolated unfamiliar items. Skilled children (mean reading age: 11 years 6 months) were more likely to adopt an analogy strategy. Experiments 2 and 3 adopted versions of the "clue word" technique used by U. Goswami (1986, Journal of Experimental Child Psychology, 42, 73-83; 1988, Quarterly Journal of Experimental Psychology, 40A, 239-268) and found a much higher incidence of analogical responding by children of all ages, suggesting that reading strategy is task-dependent. Experiment 4 showed that adults' nonword-reading strategy is determined by list composition, in that grapheme-phoneme correspondences are used more when the list context contains nonwords. It is concluded that both adults and young children exhibit considerable flexibility and task-dependence in the levels of spelling-to-sound correspondence (analogies vs decoding) that they use and that grapheme-phoneme correspondences are preferred when maximum generalization to unfamiliar items is required.

Adult↗

PubMed1996

The effect of occupational cultures on coordination of emergency medical service aircrew.

BACKGROUND/HYPOTHESIS: The purpose of the study was to see whether one can determine different occupational cultures in the Emergency Medical Air Ambulance Service and whether these differences in orientation among the crewmembers may have an impace on effective crew coordination. Due to different requirements of the Emergency Medical Service (EMS), each crewmember joins the duty with different backgrounds, interests and expectations. The operational stresses of this kind of service, however, demand teamwork and may easily expose the crew's ability to coordinate their actions to work as a team. METHOD: The initial study consisted of 60 operational crewmembers from the Norwegian Air Ambulance Service. Hofstede's questionnaire Values Survey Module was administered for an evaluation of occupational culture. RESULTS: The analysis reveals group differences at the occupational level in the perception of power distribution, team orientation and achievement preferences. CONCLUSION: We conclude that differences in certain work goals might be attributed partly by specific attitudes and values from the occupational categories' professional background, which influence the interpretation of established rules and procedures in the service. The results are further discussed in relation to the crewmembers' different task demands and areas of responsibility, and emphasis is put on organizational responsibility for enhancing safety and efficiency in the service.

Aerospace Medicine↗

PubMed2000

Brain activation patterns in schizophrenic and comparison volunteers during a matched-performance auditory recognition task.

OBJECTIVE: The biological characteristics of schizophrenia are often studied by using functional imaging techniques. However, since volunteers with schizophrenia routinely fail to perform as accurately or as quickly as healthy volunteers, it is difficult to ascertain whether a particular deficit in blood flow to a brain region is due to behavior or to the underlying illness. In this report, investigators used an auditory recognition task to assess brain blood flow patterns and behavioral correlates of schizophrenic patient volunteers trained on the task. METHOD: Twelve healthy volunteers and 18 volunteers with schizophrenia were trained to make tone frequency recognitions. Accuracy and stimuli were matched between groups. Participants were required to press a button to indicate whether a briefly presented tone was the high-frequency (1500 Hz) reference tone or one of a lower frequency level (level chosen to elicit an 80% accuracy score). Subjects underwent bolus [(15)O]H(2)O blood flow positron emission tomography during inactive rest, a sensory motor control condition, and the decision task. Blood flow patterns were assessed between conditions and between groups. RESULTS: As a group, the patients with schizophrenia (who performed as quickly and accurately as the comparison subjects) exhibited significantly less change in regional cerebral blood flow (rCBF) to the anterior cingulate and supplementary motor cortices when switching from the sensory motor control to the decision condition. There were also marked between-group differences in correlations between rCBF and response time. Whereas the comparison subjects exhibited progressively greater blood flow to the frontal cortex in association with longer response times, the schizophrenic patients exhibited progressively lower blood flow in conjunction with extended response times. CONCLUSIONS: The failure to appropriately enhance cingulate activity when engaged in a demanding task and the progressive, time-dependent decline in frontal blood flow suggest that patients with schizophrenia are unable to make optimal use of frontocingulate systems when maximally engaged in high-error tasks.

Adult↗

PubMed1994

Electroconvulsive stimulations, learning, and protein changes in the rat brain.

Two groups of rats were subjected to 17 training sessions on an operant task demanding the sequential operation of two manipulanda, while two other groups were left with no training experience. Within both the trained and passive groups one was exposed to a series of 12 electroconvulsive stimulations. The series of training and stimulation sessions were concurrent but arranged in such a way that at least 24 h always separated training and stimulation. Upon completion of the behavioural part of the experiment the concentrations of the marker proteins neural cell adhesion molecule (NCAM), D3, synaptophysin, and S100 were estimated in the prefrontal and occipital parts of the cortex, the hippocampus, and in the total forebrain. The electroconvulsively stimulated animals demonstrated severe impairment of learning. The pattern of marker protein concentrations indicated that acquisition and/or performance of the task and exposure to electroconvulsive stimulation were both accompanied by similar patterns of synaptic changes: an increased concentration of small synaptic vesicles in both the prefrontal cortex and the total forebrain and an increased synaptic remodulation in the prefrontal cortex.

Animals↗

PubMed1997

Spectacle/loupe telescope designed for reading music.

BACKGROUND: The optical needs of most low-vision patients can be satisfied with one or more of a large array of prefabricated, off-the-shelf, handheld or spectacle-mounted devices. When these devices do not provide the expected or desired results, a practitioner has the opportunity to design a custom-made device to satisfy the vision demands of the patient. CASE REPORT: A patient with a history of having tried several devices to see his music while playing the violin was examined and a simple, inexpensive. Galilean telescopic device was formulated, designed, and constructed. The objective was to create a telescope that would provide adequate magnification with a wider field of view than was available with prefabricated devices. The components needed to generate the required magnification were determined using basic telescope design concepts and equations. CONCLUSIONS: For patients with intermediate and/or distance symptoms testing with a telescope is an important part of the low-vision evaluation. Field of view, expense, and the time required to obtain the device are important considerations in deciding what to prescribe. The pathology involved, task demands, time since onset of decreased acuity, and personality of the patient will dictate, to a large degree, the acceptance of the device.

Eyeglasses↗

PubMed1997

Job strain among registered nurses and other hospital workers.

OBJECTIVE: The authors describe factors associated with job strain for various job titles in the acute care hospital using the Karasek Job Strain Model, discuss the reliability and validity of the Job Content Questionnaire, and discuss use of the model to enhance the work environment. BACKGROUND: The Karasek Job Strain Model has been used to describe many occupations in the United States and other countries. Some research indicates that occupations that arouse stress hormones are those in which employees have little job control or must complete psychologically demanding tasks, such as those under time pressure, and these positions can be describe as high-strain jobs. METHOD: This descriptive correlational study was conducted at five tertiary care hospitals on the West Coast. A purposive volunteer sample of staff members working at least 20 hours per week in the adult medical-surgical and specialty nursing units was recruited. RESULTS: Mean scores for each of the nursing units and the overall mean scores for the staff in the initial analysis fell into the Active Work quadrant of the Karasek Job Strain Model. When nursing job titles were analyzed, registered nurses had significantly higher Decision Latitude scores than did nurse assistants (P < 0.001) and clerical staff (P < 0.001), but there were no significant differences for Psychological Demands. CONCLUSIONS: Working with nurse assistants to appropriately increase decision latitude related to their work has the potential to enhance the work environment by reducing job strain and improving staff health and morale.

Adult↗

PubMed1997

Visual scanning and pilot expertise: the role of attentional flexibility and mental model development.

In order to examine differences in flying expertise, 12 novice and 12 expert pilots flew a 7-segment simulation pattern under specific attentional constraints while cockpit instrument visual scan was recorded. Flight segments involved various combinations of maneuvering of heading, altitude and airspeed. Expert pilots performed better than novices on vertical and longitudinal, but not lateral control. They accomplished their superior vertical tracking by allocating more control resources to the vertical control. Analyses of scanning strategies revealed that experts: a) had shorter dwells and more frequent visits to most instruments; b) adapted their visiting strategy more flexibly in response to changing task demands; c) demonstrated a better mental model of cross-coupling and predictive relations between and within axes; and d) showed more frequent checking of axes whose values remained constant. The data is discussed in terms of their implications in pilot cockpit scan training program development.

Adolescent↗

PubMed2007

Goal-directed training: linking theories of treatment to clinical practice for improved functional activities in daily life.

BACKGROUND: Goal-directed training is an activity-based approach to therapy. Meaningful, client-selected goals are used to provide opportunities for problem solving and to indirectly drive the movements required to successfully meet the task demands. This is in contrast to interventions that focus on changing body functions. Here, the principles of goal-directed training will be studied through two case studies with the aim of linking theories of treatment to clinical practice. PRINCIPLES ILLUSTRATED: The approach is based on the dynamic systems motor control theory and occupation-based therapy models, which suggest that movement patterns emerge from the interaction between the person's abilities, environment and the goal. Motor learning principles are applied to structure and schedule practice. THEORY IN PRACTICE: Four components provide the basis for goal-directed training: (1) selection of a meaningful goal; (2) analysis of baseline performance; (3) intervention/ practice regime; and (4) evaluation of outcome. Two individuals with acquired brain injury practised self-care tasks: eating and tying hair into a ponytail. Intensive training was undertaken over four weeks and the intervention outcome measured using the Goal Attainment Scale. CONCLUSIONS: The positive achievements in the self-care tasks illustrated that theories of motor control and motor learning can be applied to goal-directed training. The examples demonstrated that the approach could be applied to individuals with a range of abilities.

Activities of Daily Living↗

PubMed1995

Going beyond heart rate: autonomic space and cardiovascular assessment of mental workload.

Psychophysiological assessment of pilot mental workload using heart rate should be augmented with an autonomic space model of cardiovascular function. This model proposes that autonomic nervous system influences on the heart may change with psychological processing in ways that are not evident in heart rate. A method of mental-workload assessment was proposed that used multiple psychophysiological measures of cardiovascular responsivity to derive the underlying sympathetic and parasympathetic information needed to represent the autonomic space for heart rate. Principal-components analysis was used to extract Sympathetic and Parasympathetic components from heart period, residual heart period. respiratory sinus arrhythmia, and Traube-Hering-Mayer wave in three experiments that manipulated perceptual/central processing and physical task demands. This initial evaluation of the method concluded that the autonomic components were valid and that the components had greater diagnosticity, and for some manipulations greater sensitivity, than heart rate. These results support the contention that the Sympathetic and Parasympathetic components provided increased precision for mental-workload assessment.

Adolescent↗

PubMed2006

Measuring the development of executive control with the shape school.

Although several neurodevelopmental and psychiatric disorders can emerge during the preschool period, there are comparatively few instruments to assess executive control. Evidence for validity of the Shape School (K. A. Espy, 1997) was examined in a sample of 219 typically developing young children. There was good evidence for validity, as Shape School performance variables were interrelated and were associated to other criterion measures considered to measure aspects of executive control. Also suggesting validity, the Shape School variables varied as a function of whether the task demands (a) were executive, (b) required inhibition of a prepotent response or context-controlled selection among relevant stimulus-response sets, and (c) included unitary or concurrent processing. The Shape School may be an effective tool by which to measure executive control in young children who have atypical developmental patterns.

Attention↗

PubMed1999

Coherence of sequential movements and motor learning.

The analysis of oscillatory EEG phenomena such as interregional coherence (task-related coherence [TRCoh] or event-related coherence) has advanced our knowledge of neurophysiological processes underlying the performance and learning of skilled finger movements. It has become clear that various types of higher task demands are reflected by changes in the functional coupling of different cortical areas and not only by changes in regional activation. Neuroscientists are merely starting to understand how coherent oscillations might encode information in the human motor system ("sensorimotor binding") and how well this can be measured from the surface EEG. However, interregional coherence is a potentially independent mechanism that can, up to now, only be investigated with electrophysiological techniques such as EEG and MEG. The studies reviewed below focus on coherence of finger movements and motor learning: increasing complexity of a movement sequence, internal rhythm generation, visuomotor integration, deficits in interhemispheric coupling, and bimanual coordination. Evidence is presented for a special functional significance of TRCoh in the beta frequency range (13 to 21 Hz) for information processing in large-scale sensorimotor networks during motor tasks.

Electroencephalography↗

PubMed1984

Cardiovascular responses to static exercise.

In light static exercise the heart rate and blood pressure increase much more than during dynamic exercise at the same oxygen uptake level. Heavy static exercise is characterized by a failure of the local blood flow to adjust to the oxygen demands of the exercising muscles. Respiratory and circulatory responses are dominated by an incompetence to obtain steady-state conditions, and thus the worktime is short. After the cessation of heavy static exercise a sudden compensatory increase occurs in cardiac output and oxygen uptake. Due to the higher increase in blood pressure, even light static exercise causes much higher strain on the heart than an equivalent amount of dynamic exercise. The heart responds to the increased afterload by increasing contractility and heart rate and thus improves cardiac output. In persons with a poor cardiac reserve a rise in the left ventricular end-diastolic pressure is seen, along with a fall in the stroke work index in response to the increased afterload caused by static exercise. It is possible that a discrepancy exists between work capacity during tasks demanding also isometric muscle work and a dynamic exercise test performance. The decreased cardiac reserve may first appear after the great increase in afterload, even in relatively light static work.

Adaptation, Physiological↗

PubMed2006

Intact discrimination reversal learning but slowed responding to reward-predictive cues after dopamine D1 and D2 receptor blockade in the nucleus accumbens of rats.

RATIONALE: The prediction error hypothesis of dopamine action states that dopamine signals are necessary for the brain to update the predictive significance of cues. Yet, little is known whether D1 or D2 receptor-mediated signals in the nucleus accumbens core (AcbC) are required to learn a reversal of the predictive significance of cues. OBJECTIVE: Here we examined the effects of a selective D1 or D2 receptor blockade in the AcbC on learning a reversal of previously acquired cue-reward magnitude contingencies. MATERIALS AND METHODS: Rats were trained on a reaction time (RT) task demanding conditioned lever release with discriminative visual cues signalling in advance the upcoming reward magnitude (one or five food pellets). After acquisition, RTs were guided by cue-associated reward magnitudes, i.e. RTs of responses were significantly shorter for expected high vs low reward. Thereafter, cue-reward magnitude contingencies were reversed. Reversal learning was tested for 12 daily sessions with intra-AcbC micro-infusions being given on sessions 1-6. Subjects received pre-trial infusions of the selective D1 or D2 receptor antagonists, SCH23390 (0.5, 2 microg per side) or raclopride (1, 4 microg per side), or vehicle (0.5 microl). RESULTS: Intra-AcbC infusion of SCH23390 (0.5, 2 microg) or raclopride (1, 4 microg) did not inhibit discrimination reversal learning, but the higher dose of each drug increased RTs of instrumental responses. CONCLUSIONS: In a visual discrimination task as used here, D1 and D2 receptor-mediated signals in the AcbC seem to be unnecessary in updating the reward-predictive significance of cues, rather, they serve to activate instrumental behaviour.

Animals↗

PubMed1993

The difficulty with recalling people's names: the plausible phonology hypothesis.

Recalling the name of a person is a simple, but often a problematic, everyday task. There are various explanations of this phenomenon, but here it is argued that the explanations offered so far, by failing to consider learning of names, have overlooked a simple account of name recall difficulty. The starting observation for this viewpoint is that names of people are often non-words, in that they have never been encountered before. This is not true of, say, names of professions. Not only does the relatively high rate of new exemplars mean that people's names are likely to be underlearned, but furthermore, even for equal degrees of learning, a person's name is at a disadvantage because of the high plausibility of most phonologies: "dreaner" is much more readily accepted as the name of a person than as the name of their profession. So specifying the phonology of people's names is inherently a more demanding task, compared to the phonology of other names. The implications of this view are explored with regard to explanations of empirically established name recall phenomena in normal subjects, the patterns of performance of anomic patients and the difficulty of name recall in different word domains. It is shown that these arguments, derived from a real world fact, account in a simple way for existing data and make predictions in different areas of research.

Age Factors↗

PubMed2004

Changes in brain activation during the acquisition of a new bimanual coodination task.

Motor skill acquisition is associated with the development of automaticity and induces neuroplastic changes in the brain. Using functional magnetic resonance imaging (fMRI), the present study traced learning-related activation changes during the acquisition of a new complex bimanual skill, requiring a difficult spatio-temporal relationship between the limbs, i.e., cyclical flexion-extension movements of both hands with a phase offset of 90 degrees. Subjects were scanned during initial learning and after the coordination pattern was established. Kinematics of the movements were accurately registered and showed that the new skill was acquired well. Learning-related decreases in activation were found in right dorsolateral prefrontal cortex (DLPFC), right premotor, bilateral superior parietal cortex, and left cerebellar lobule VI. Conversely, learning-related increases in activation were observed in bilateral primary motor cortex, bilateral superior temporal gyrus, bilateral cingulate motor cortex (CMC), left premotor cortex, cerebellar dentate nuclei/lobule III/IV/Crus I, putamen/globus pallidus and thalamus. Accordingly, bimanual skill learning was associated with a shift in activation among cortico-subcortical regions, providing further evidence for the existence of differential cortico-subcortical circuits preferentially involved during the early and advanced stages of learning. The observed activation changes account for the transition from highly attention-demanding task performance, involving processing of sensory information and corrective action planning, to automatic performance based on memory representations and forward control.

Adult↗

PubMed2003

Assessing the compatibility of work system factors through an integrative model: a case study.

Work Factor Compatibility (WFC) theory proposes that human performance is dependent on the interaction of various components (e.g., physical and mental task demands, physical environment, social environment) of the work system and integrates multiple human performance perspectives into a single mathematical model. Work Factor Analysis (WFA) is a comprehensive survey administered to employees to determine the WFC index. WFA also provides recommendations for targeting specific work system areas for improvement. Preliminary testing of the tool was conducted at a manufacturing operation of a Fortune 10 company. Results are discussed and recommendations for further study are made.

Efficiency↗

PubMed2006

Trunk biomechanical models based on equilibrium at a single-level violate equilibrium at other levels.

Accurate estimation of muscle forces in various occupational tasks is critical for a reliable evaluation of spinal loads and subsequent assessment of risk of injury and management of back disorders. The majority of biomechanical models of multi-segmental spine estimate muscle forces and spinal loads based on the balance of net moments at a single level with no consideration for the equilibrium at remaining levels. This work aimed to quantify the extent of equilibrium violation and alterations in estimations when such models are performed at different levels. Results are compared with those of kinematics-driven model that satisfies equilibrium at all levels and EMG data. Regardless of the method used (optimization or EMG-assisted), single-level free body diagram models yielded estimations that substantially altered depending on the level considered (i.e., level dependency). Equilibrium of net moment was also grossly violated at remaining levels with the error increasing in more demanding tasks. These models may, however, be used to estimate spinal compression forces.

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