Task modulation of brain responses in visual word recognition as studied using EEG/MEG and fMRI.

Do task demands change the way we extract information from a stimulus, or only how we use this information for decision making? In order to answer this question for visual word recognition, we used EEG/MEG as well as fMRI to determine the latency ranges and spatial areas in which brain activation to words is modulated by task demands. We presented letter strings in three tasks (lexical decision, semantic decision, silent reading), and measured combined EEG/MEG as well as fMRI responses in two separate experiments. EEG/MEG sensor statistics revealed the earliest reliable task effects at around 150 ms, which were localized, using minimum norm estimates (MNE), to left inferior temporal, right anterior temporal and left precentral gyri. Later task effects (250 and 480 ms) occurred in left middle and inferior temporal gyri. Our fMRI data showed task effects in left inferior frontal, posterior superior temporal and precentral cortices. Although there was some correspondence between fMRI and EEG/MEG localizations, discrepancies predominated. We suggest that fMRI may be less sensitive to the early short-lived processes revealed in our EEG/MEG data. Our results indicate that task-specific processes start to penetrate word recognition already at 150 ms, suggesting that early word processing is flexible and intertwined with decision making.

Consultants in Scotland: survey of educational qualifications, experience and needs of Scottish consultants.

AIMS: To survey Scotland's NHS consultants regarding their teaching roles; educational qualifications/training; attitudes to educational qualifications; perceptions of health boards' attitudes to educational activities; usefulness of various educational courses and preferred delivery methods. METHODS: Postal questionnaire (n=3615). RESULTS: Sixty two percent response rate (n=2246). 98% had one or more roles in education/training. 54% spent more time in educational roles than job-plan allocations. 6% had educational qualifications. 30% rated educational qualifications valuable to their educational role; 21% to their career. 48% had not attended any educational training. 19% of respondents rated their health board as supportive of their educational activities. Respondents rated dealing with underperforming students (74%), dealing with challenging behaviour (63%), appraising students (63%), trainee assessment (61%) and feedback (58%) as the most useful topics. CONCLUSIONS: Scottish consultant involvement in educational activities is virtually universal but consultants perceive they need more time than allocated in job plans. Most consultants had no teaching qualifications. Nearly half had no formal training for educational activities. Educational qualifications were valued by a minority regarding both career development and educational activities. Increased access to staff development for teaching is required as NHS sources are not meeting the need for teacher training of consultant staff.

Towards the routine use of brain imaging to aid the clinical diagnosis of disorders of consciousness.

Clinical audits have highlighted the many challenges and dilemmas faced by clinicians assessing persons with disorders of consciousness (vegetative state and minimally conscious state). The diagnostic decision-making process is highly subjective, dependent upon the skills of the examiner and invariably dictated by the patients' ability to move or speak. Whilst a considerable amount has been learnt since Jennett and Plum coined the term 'vegetative state', the assessment process remains largely unchanged; conducted at the bedside, using behavioural assessment tools, which are susceptible to environmental and physiological factors. This has created a situation where the rate of misdiagnosis is unacceptably high (up to 43%). In order to address these problems, various functional brain imaging paradigms, which do not rely upon the patient's ability to move or speak, have been proposed as a source of additional information to inform the diagnostic decision making process. Although accumulated evidence from brain imaging, particularly functional magnetic resonance imaging (fMRI), has been encouraging, the empirical evidence is still based on relatively small numbers of patients. It remains unclear whether brain imaging is capable of informing the diagnosis beyond the behavioural assessment and whether brain imaging has any prognostic utility. In this study, we describe the functional brain imaging findings from a group of 41 patients with disorders of consciousness, who undertook a hierarchical speech processing task. We found, contrary to the clinical impression of a specialist team using behavioural assessment tools, that two patients referred to the study with a diagnosis of vegetative state did in fact demonstrate neural correlates of speech comprehension when assessed using functional brain imaging. These fMRI findings were found to have no association with the patient's behavioural presentation at the time of investigation and thus provided additional diagnostic information beyond the traditional clinical assessment. Notably, the utility of brain imaging was further underlined by the finding that the level of auditory processing revealed by functional brain imaging, correlated strongly (rs = 0.81, P < 0.001) with the patient's subsequent behavioural recovery, 6 months after the scan, suggesting that brain imaging may also provide valuable prognostic information. Although further evidence is required before consensus statements can be made regarding the use of brain imaging in clinical decision making for disorders of consciousness, the results from this study clearly highlight the potential of imaging to inform the diagnostic decision-making process for persons with disorders of consciousness.

Can I have a quick word? Early electrophysiological manifestations of psycholinguistic processes revealed by event-related regression analysis of the EEG.

We applied multiple linear regression analysis to event-related electrophysiological responses to words and pseudowords in a visual lexical decision task, yielding event-related regression coefficients (ERRCs) instead of the traditional event-related potential (ERP) measure. Our main goal was to disentangle the earliest ERP effects of the length of letter strings ("word length") and orthographic neighbourhood size (Coltheart's "N"). With respect to N, existing evidence is still ambiguous with respect to whether effects of N reflect early access to lexico-semantic information, or whether they occur at later decision or verification stages. In the present study, we found distinct neurophysiological manifestations of both N and word length around 100ms after word onset. Importantly, the effect of N distinguished between words and pseudowords, while the effect of word length did not. Minimum norm source estimation revealed the most dominant sources for word length in bilateral posterior brain areas for both words and pseudowords. For N, these sources were more left-lateralised and consistent with perisylvian brain areas, with activation peaks in temporal areas being more anterior for words compared to pseudowords. Our results support evidence for an effect of N at early and elementary stages of word recognition. We discuss the implications of these results for the time line of word recognition processes, and emphasise the value of ERRCs in combination with source analysis in psycholinguistic and cognitive brain research.

When thoughts become action: an fMRI paradigm to study volitional brain activity in non-communicative brain injured patients.

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the neural correlates of consciousness, even a normal activation in response to passive sensory stimulation cannot be considered as proof of the presence of awareness in these patients. In contrast, predicted activation in response to the instruction to perform a mental imagery task would provide evidence of voluntary task-dependent brain activity, and hence of consciousness, in non-communicative patients. However, no data yet exist to indicate which imagery instructions would yield reliable single subject activation. The aim of the present study was to establish such a paradigm in healthy volunteers. Two exploratory experiments evaluated the reproducibility of individual brain activation elicited by four distinct mental imagery tasks. The two most robust mental imagery tasks were found to be spatial navigation and motor imagery. In a third experiment, where these two tasks were directly compared, differentiation of each task from one another and from rest periods was assessed blindly using a priori criteria and was correct for every volunteer. The spatial navigation and motor imagery tasks described here permit the identification of volitional brain activation at the single subject level, without a motor response. Volunteer as well as patient data [Owen, A.M., Coleman, M.R., Boly, M., Davis, M.H., Laureys, S., Pickard J.D., 2006. Detecting awareness in the vegetative state. Science 313, 1402] strongly suggest that this paradigm may provide a method for assessing the presence of volitional brain activity, and thus of consciousness, in non-communicative brain-injured patients.

The time course of visual word recognition as revealed by linear regression analysis of ERP data.

EEG correlates of a range of psycholinguistic word properties were used to investigate the time course of access to psycholinguistic information during visual word recognition. Neurophysiological responses recorded in a visual lexical decision task were submitted to linear regression analysis. First, 10 psycholinguistic features of each of 300 stimulus words were submitted to a principal component analysis, which yielded four orthogonal variables likely to reflect separable processes in visual word recognition: Word length, Letter n-gram frequency, Lexical frequency and Semantic coherence of a word's morphological family. Since the lexical decision task required subjects to distinguish between words and pseudowords, the binary variable Lexicality was also investigated using a factorial design. Word-pseudoword differences in the event-related potential first appeared at 160 ms after word onset. However, regression analysis of EEG data documented a much earlier effect of both Word length and Letter n-gram frequency around 90 ms. Lexical frequency showed its earliest effect slightly later, at 110 ms, and Semantic coherence significantly correlated with neurophysiological measures around 160 ms, simultaneously with the lexicality effect. Source estimates indicated parieto-temporo-occipital generators for the factors Length, Letter n-gram frequency and Word frequency, but widespread activation with foci in left anterior temporal lobe and inferior frontal cortex related to Semantic coherence. At later stages (>200 ms), all variables exhibited simultaneous EEG correlates. These results indicate that information about surface form and meaning of a lexical item is first accessed at different times in different brain systems and then processed simultaneously, thus supporting cascaded interactive processing models.

Portfolio assessment in medical students' final examinations.

The introduction of an outcome-based approach to education at Dundee Medical School in Scotland instigated a search for assessment methods that would appropriately assess the students' achievements in terms of the learning outcomes. Portfolio assessment has been developed for this purpose and has been adopted for the summative assessment of students in their final examination in Dundee. The contents of the portfolio and the assessment process have been defined and the first cohort of students to be assessed in this way has been studied. The evaluation of the approach demonstrated strong staff support. Students were also positive although with some reservations. It is concluded that portfolio assessment is a powerful approach to assessing a range of curriculum outcomes not easily assessed by other methods and is worthy of inclusion in the assessor's toolkit.

AMEE Medical Education Guide No. 24: Portfolios as a method of student assessment.

This guide is intended to inform medical teachers about the use of portfolios for student assessment. It provides a background to the topic, reviews the range of assessment purposes for which portfolios have been used, identifies possible portfolio contents and outlines the advantages of portfolio assessment with particular focus on assessing professionalism. The experience of one medical school, the University of Dundee, is presented as a case study. The current state of understanding of the technical, psychometric issues relating to portfolio assessment is clarified. The final part of the paper provides a practical guide for those wishing to design and implement portfolio assessment in their own institutions. Five steps in the portfolio assessment process are identified: documentation, reflection, evaluation, defence and decision. It is concluded that portfolio assessment is an important addition to the assessor's toolkit. Reasons for using portfolios for assessment purposes include the impact that they have in driving student learning and their ability to measure outcomes such as professionalism that are difficult to assess using traditional methods.

Susceptibility-induced loss of signal: comparing PET and fMRI on a semantic task.

Functional magnetic resonance imaging (fMRI) has become a popular tool for investigations into the neural correlates of cognitive activity. One limitation of fMRI, however, is that it has difficulty imaging regions near tissue interfaces due to distortions from macroscopic susceptibility effects which become more severe at higher magnetic field strengths. This difficulty can be particularly problematic for language tasks that engage regions of the temporal lobes near the air-filled sinuses. This paper investigates susceptibility-induced signal loss in the temporal lobes and proposes that by defining a priori regions of interest and using the small-volume statistical correction of K. J. Worsley, S. Marrett, P. Neelin, A. C. Vandal, K. J. Friston, and A. C. Evans (1996, Hum. Brain Mapp. 4: 58-83), activations in these areas can sometimes be detected by increasing the statistical power of the analysis. We conducted two experiments, one with PET and the other with fMRI, using almost identical semantic categorization paradigms and comparable methods of analysis. There were areas of overlap as well as differences between the PET and fMRI results. One anticipated difference was a lack of activation in two regions in the temporal lobe on initial analyses in the fMRI data set. With a specific region of interest, however, activation in one of the regions was detected. These experiments demonstrate three points: first, even for almost identical cognitive tasks such as those in this study, PET and fMRI may not produce identical results; second, differences between the two methods due to macroscopic susceptibility artifacts in fMRI can be overcome with appropriate statistical corrections, but only partially; and third, new data acquisition paradigms are necessary to fully deal with susceptibility-induced signal loss if the sensitivity of the fMRI experiment to temporal lobe activations is to be enhanced.

Task-based learning: the answer to integration and problem-based learning in the clinical years.

INTRODUCTION: Integrated teaching and problem-based learning (PBL) are powerful educational strategies. Difficulties arise, however, in their application in the later years of the undergraduate medical curriculum, particularly in clinical attachments. Two solutions have been proposed - the use of integrated clinical teaching teams and time allocated during the week for PBL separate from the clinical work. Both approaches have significant disadvantages. Task-based learning (TBL) is a preferred strategy. In TBL, a range of tasks undertaken by a doctor are identified, e.g. management of a patient with abdominal pain, and these are used as the focus for learning. Students have responsibility for integrating their learning round the tasks as they move through a range of clinical attachments in different disciplines. They are assisted in this process by study guides. METHOD: The implementation of TBL is described in one medical school. One hundred and thirteen tasks, arranged in 16 groups, serve to integrate the student learning as they rotate through 10 clinical attachments. RESULTS: This trans-disciplinary approach to integration, which incorporates the principles of PBL offers advantages to both teachers and students. It recognizes that clinical attachments in individual disciplines can offer rich learning opportunities and that such attachments can play a role in an integrated, as well as in a traditional, curriculum. In TBL, the contributions of the clinical attachments to the curriculum learning outcomes must be clearly defined and tasks selected which will serve as a focus for the integration of the students' learning over the range of attachments.

An evaluation of CASES--an educational audit programme for orthodontists.

A regional approach to a national clinical audit programme in orthodontics in the UK is described and evaluated. The programme was designed using the CRISIS criteria for effective continuing education. Programme participants completed duplicate questionnaires on 6 simulated patient scenarios, chosen for their relevance to everyday practice while posing important clinical dilemmas. The participation rate was 77% from hospital-based practitioners and 29% from specialist practitioners. Feedback to programme participants was given in the form of histograms, and provided a snapshot of national approaches to patient investigation, treatment and expected outcomes. A commentary on the data and references to appropriate articles in the literature were included. Evaluation of the programme by questionnaire survey showed that it was extensively used by hospital-based practitioners. It is concluded that the model used provided an effective and efficient framework for conducting clinical audit and delivering continuing education to the hospital-based group.

Approaches to eliminating sociocultural disparities in health.

The recent flurry of studies documenting the presence of racial, ethnic, and socioeconomic disparities in health care and health have outpaced articles that describe effective strategies to eliminate disparities. Through literature review and informal interviews with research, policy, and program experts, we developed a framework of programs that address disparities through targeting clinicians, patients and communities, and health systems. We found that the lack of technical expertise, resources, and sensitive tools are all common barriers to evaluating programs. To stimulate more effective programs and rigorous evaluations, we describe specialized implementation and evaluation techniques programs can use, and make recommendations for future efforts.

Empathy, expectations, and situational preferences: personality influences on the decision to participate in volunteer helping behaviors.

Although considerable evidence indicates that dispositional empathy is associated with the degree of help that observers will offer needy targets, little is known about the effect of empathy on one's initial willingness to enter situations in which such needy targets might be found. Three studies were conducted to evaluate two related propositions: (1) that dispositional empathy influences such situational preferences, and (2) that this influence is mediated by the expectancies one holds regarding the emotions likely to occur in those situations. Using hypothetical judgments, Study 1 found support for both propositions. Study 2, in which participants believed that their responses actually committed them to encountering needy targets, provided further support for the model, as did Study 3, which examined the experiences of actual community volunteers. The theoretical and practical implications of these findings are discussed.

AMEE Medical Education Guide No. 15: Problem-based learning: a practical guide.

This practical guide for health professions teachers provides a perspective of one of the most important educational developments in the past 30 years.Problem-based learning (PBL) is a continuum of approaches rather than one immutable process. It is a teaching method that can be included in the teacher's tool-kit along with other teaching methods rather than used as the sole educational strategy.PBL reverses the traditional approach to teaching and learning. It starts with individual examples or problem scenarios which stimulate student learning. In so doing, students arrive at general principles and concepts which they then generalize to other situations. PBL has many advantages. It facilitates the acquisition of generic competences, encourages a deep approach to learning and prepares students for the adult learning approach they need for a lifetime of learning in the health care professions. It is also fun. PBL helps in curriculum planning by defining core, ensuring relevance of content, integrating student learning and providing prototype cases. There are also drawbacks associated with PBL. Students may fail to develop an organized framework for their knowledge. The PBL process may inhibit good teachers sharing their enthusiasm for their topic with students and student identification with good teachers.Teachers may not have the skills to facilitate PBL.The problem scenario is of crucial significance. It should engage the students' interest and be skilfully written. While the medium selected for presentation of the scenario is usually print, other media may be used.The clinical tasks carried out by the student may replace the problem scenario as the focus for learning.Students are supported during the PBL process by tutors and/or study guides.The amount of support required is inversely related to the students' prior learning and understanding of the PBL process. A range of additional learning resources and opportunities may be made available to the students, including textbooks, videotapes, computer-based material, lectures and clinical sessions. Tutors require group facilitation skills, an understanding of the PBL process and knowledge of the course and of the curriculum in general.They need special personal qualities and it is preferable if they have expertise in the content area.While special assessment processes have been developed to assess students learning by the PBL method, the general principles of assessment apply to PBL courses and a mixed menu of assessment methods needs to be employed. Curriculum design involves a skilful blend of educational strategies designed to help students achieve the curriculum outcomes. PBL may make a valuable contribution to this blend but attention needs to be paid to how it is implemented.

AMEE Guide No. 14: Outcome-based education: Part 5-From competency to meta-competency: a model for the specification of learning outcomes.

Increased attention is being paid to the specification of learning outcomes.This paper provides a framework based on the three-circle model: what the doctor should be able to do ('doing the right thing'), the approaches to doing it ('doing the thing right') and the development of the individual as a professional ('the right person doing it').Twelve learning outcomes are specified, and these are further subdivided.The different outcomes have been defined at an appropriate level of generality to allow adaptability to the phases of the curriculum, to the subject matter, to the instructional methodology and to the students' learning needs. Outcomes in each of the three areas have distinct underlying characteristics.They move from technical competences or intelligences to meta-competences including academic, emotional, analytical, creative and personal intelligences. The Dundee outcome model offers an intuitive, user-friendly and transparent approach to communicating learning outcomes. It encourages a holistic and integrated approach to medical education and helps to avoid tension between vocational and academic perspectives.The framework can be easily adapted to local needs. It emphasizes the relevance and validity of outcomes to medical practice.The model is relevant to all phases of education and can facilitate the continuum between the different phases. It has the potential of facilitating a comparison between different training programmes in medicine and between different professions engaged in health care delivery.

An adult with a severe Class II division 1 malocclusion: Frances' case.

This article describes treatment options for an adult with a severe Class II division 1 malocclusion. The opinions of British orthodontists, as obtained through the CASES project, are summarized and the patient's actual treatment is discussed.