Debating point - The artificial and elusive demarcation between health and disease

A number of problems and uncertainties have been raised by this brief review. Although they are well-known in philosophical and social scientific circles they are otherwise consistently ignored. But I call for a wider debate about them. If medicine cannot come to terms with its own confusing terminology and methodology; if medicine cannot stop raising expectations it cannot fulfil; if medicine does not deliberately restrict its boundaries; and if medicine does not take serious steps to explain why it chooses to call some conditions states of health and others states of disease; then the result must be that health policy (which medicine largely continues to direct) will either be simply an arbitrary matter, or will be implemented on the basis of economic arguments. Where everything else is imprecise the discipline that offers precision will triumph. And the evidence of the moment is that this is exactly what is happening

Decision-making strategies in the general practice

With regard to the question what is to be tran$mitted in teaching two aspects have to be considered: a) the contents of the specialty; and b) the problem-solving methods with regard to the specialty. On the first aspect an overwhelming amoUnt of book$ and articles has bee~ written in medicine. The second 8Spect is usually only mentioned in passing. In my opinion, ~his subject has thusfar been greatly undervalued. When one is unable to trace the - problem-solving processes how can anyone determine the efficscy, the effectivity, and the efficiency of this process, or value~ the outcome. To state it in Magerien terms: "If you do not know where to g;o, you may very well end up somewhere else- and not even know it." How physicians solve clinical problems is the main object of this research. The investigator studied and modeled two of the eldest and famous ways of pJroblei!Jlrsolving: the deductive and the inductive strategy9 with the modern probability reasoning viewed as an extension of the latter strategy. All 68 physicians who participated in this investigation used the inductive strategy for the -usually four - presented patient-problems. Within the inductive strategy three variants could be distinguished. The consequences of this finding are far-reaching. As the inductive strategy does not include a logical hierarchy of argumentationsteps, retracing of the process is impossible. (This aspect is also relate~ to our opinions about experience-knowledge end teaching)A As the hypothesis generation is prior to the acquisition of infot~tion, this latter aspect can only be viewed in the light of the former~ and thus limited to a small number of domains. As the hypothesis generation is - partly - unrelated to the total available amount of information, the decision making (chopsing the ultimate diagnostic hypothesis) will usually follow implicit~ personal trends and standards, e.g. satisfying minimal eicpectations (Satisficing Theory, Simon} or risk-avoiding prospects (Prospect Theory, Kahnemann & Tversky). It suggests a highly personal character of diagnostics and/or the therapeutic management, which is contradictory to general accessibility of medical knowledge and medical teaching. This feature of personal concepts easily links up with Polanyi's theory of "PeJrsonal" or 91Tacit Knowledge" as contrasted to "Objective Knowledge" (Popper) 9 which has general accessibility and validity. During the investigation this as~oct came forth. The framework of the investigation (patient simulation) end the special definitions and coding of illness elements (symptoms, signs9 tests) all~wed for comparing similar conceptions (diagnoses, treatments) ~ong the participants. These comparisons confirm Polanyi's theory and the concepts of inductive reasoning. Mutual comparibility of diagnoses seems hardly possible when analysing these conceptions into their basic elements (symptoms etc.). This aspect touches upon one of the main cornerstones of clinical ~edicine. When the starting positions have not been unequivocally defined treatment, .,;ie-Jed as the intervention in the natural course of a disease, can only lead t4:!1 uncertain outcomes. The lack of · standardized :medical definitions and a tmiform, unambiguous taxonomy inhibits the application of a formalised, normative decision theorry for clinical medicine. Future planning aims at a reconsideration of medical terminology~ medical taxonomy and medical problem-solving methods by means of clustering the basic elements of clinical medicine

Informational and Neuromuscular Contributions to Anchoring in Rhythmic Wrist Cycling

Continuous rhythmic movements are often geared toward particular points in the movement cycle, as evidenced by a local reduction in trajectory variability. These so-called anchor points provide a window into motor control, since changes in the degree of anchoring may reveal how informational and/or neuromuscular properties are exploited in the organization of rhythmic movements. The present experiment examined the relative contributions of informational timing (metronome beeps) and neuromuscular (wrist postures) constraints on anchoring by systematically varying both factors at movement reversal points. To this end, participants cycled their right wrist in a flexed, neutral, or extended posture, either self-paced or synchronized to a metronome pacing peak flexion, peak extension, or both peak flexion and extension. The effects of these manipulations were assessed in terms of kinematics, auditory-motor coordination, and muscle activity. The degree of anchoring seen at the reversal points depended on the degree of compatibility of the prevailing configuration of neuromuscular and informational timing constraints, which had largely independent effects. We further observed systematic changes in muscular activity, which revealed distinct contributions of posture- and muscle-dependent neuromuscular properties to motor control. These findings indicate that the anchor-based discretization of the control of continuous rhythmic wrist movements is determined by both informational timing and neuromuscular constraints in a task-specific manner with subtle interactions between the two, and exemplify how movement variability may be exploited to gain such insights

Error correction in bimanual coordination benefits from bilateral muscle activity: evidence from kinesthetic tracking

Although previous studies indicated that the stability properties of interlimb coordination largely result from the integrated timing of efferent signals to both limbs, they also depend on afference-based interactions. In the present study, we examined contributions of afference-based error corrections to rhythmic bimanual coordination using a kinesthetic tracking task. Furthermore, since we found in previous research that subjects activated their muscles in the tracked (motor-driven) arm, we examined the functional significance of this activation to gain more insight into the processes underlying this phenomenon. To these aims, twelve subjects coordinated active movements of the right hand with motor-driven oscillatory movements of the left hand in two coordinative patterns: in-phase (relative phase 0°) and antiphase (relative phase 180°). They were either instructed to activate the muscles in the motor-driven arm as if moving along with the motor (active condition), or to keep these muscles as relaxed as possible (relaxed condition). We found that error corrections were more effective in in-phase than in antiphase coordination, resulting in more adequate adjustments of cycle durations to compensate for timing errors detected at the start of each cycle. In addition, error corrections were generally more pronounced in the active than in the relaxed condition. This activity-related difference was attributed to the associated bilateral neural control signals (as estimated using electromyography), which provided an additional reference (in terms of expected sensory consequences) for afference-based error corrections. An intimate relation was revealed between the (integrated) motor commands to both limbs and the processing of afferent feedback

Group differences in physician responses to handheld presentation of clinical evidence: a verbal protocol analysis

<p>Abstract</p> <p>Background</p> <p>To identify individual differences in physicians' needs for the presentation of evidence resources and preferences for mobile devices.</p> <p>Methods</p> <p>Within-groups analysis of responses to semi-structured interviews. Interviews consisted of using prototypes in response to task-based scenarios. The prototypes were implemented on two different form factors: a tablet style PC and a pocketPC. Participants were from three user groups: general internists, family physicians and medicine residents, and from two different settings: urban and semi-urban. Verbal protocol analysis, which consists of coding utterances, was conducted on the transcripts of the testing sessions. Statistical relationships were investigated between staff physicians' and residents' background variables, self-reported experiences with the interfaces, and verbal code frequencies.</p> <p>Results</p> <p>47 physicians were recruited from general internal medicine, family practice clinics and a residency training program. The mean age of participants was 42.6 years. Physician specialty had a greater effect on device and information-presentation preferences than gender, age, setting or previous technical experience. Family physicians preferred the screen size of the tablet computer and were less concerned about its portability. Residents liked the screen size of the tablet, but preferred the portability of the pocketPC. Internists liked the portability of the pocketPC, but saw less advantage to the large screen of the tablet computer (F[2,44] = 4.94, p = .012).</p> <p>Conclusion</p> <p>Different types of physicians have different needs and preferences for evidence-based resources and handheld devices. This study shows how user testing can be incorporated into the process of design to inform group-based customization.</p

Computer-aided DSM-IV-diagnostics – acceptance, use and perceived usefulness in relation to users' learning styles

BACKGROUND: CDSS (computerized decision support system) for medical diagnostics have been studied for long. This study was undertaken to investigate how different preferences of Learning Styles (LS) of psychiatrists might affect acceptance, use and perceived usefulness of a CDSS for diagnostics in psychiatry. METHODS: 49 psychiatrists (specialists and non-specialists) from 3 different clinics volunteered to participate in this study and to use the CDSS to diagnose a paper-based case (based on a real patient). LS, attitudes to CDSS and complementary data were obtained via questionnaires and interviews. To facilitate the study, a special version of the CDSS was created, which automatically could log interaction details. RESULTS: The LS preferences (according to Kolb) of the 49 physicians turned out as follows: 37% were Assimilating, 31% Converging, 27% Accommodating and 6% Diverging. The CDSS under study seemed to favor psychiatrists with abstract conceptualization information perceiving mode (Assimilating and Converging learning styles). A correlation between learning styles preferences and computer skill was found. Positive attitude to computer-aided diagnostics and learning styles preferences was also found to correlate. Using the CDSS, the specialists produced only 1 correct diagnosis and the non-specialists 2 correct diagnoses (median values) as compared to the three predetermined correct diagnoses of the actual case. Only 10% had all three diagnoses correct, 41 % two correct, 47 % one correct and 2 % had no correct diagnose at all. CONCLUSION: Our results indicate that the use of CDSS does not guarantee correct diagnosis and that LS might influence the results. Future research should focus on the possibility to create systems open to individuals with different LS preferences and possibility to create CDSS adapted to the level of expertise of the user

Comparing unilateral and bilateral upper limb training: The ULTRA-stroke program design

<p>Abstract</p> <p>Background</p> <p>About 80% of all stroke survivors have an upper limb paresis immediately after stroke, only about a third of whom (30 to 40%) regain some dexterity within six months following conventional treatment programs. Of late, however, two recently developed interventions - constraint-induced movement therapy (CIMT) and bilateral arm training with rhythmic auditory cueing (BATRAC) - have shown promising results in the treatment of upper limb paresis in chronic stroke patients. The ULTRA-stroke (acronym for Upper Limb TRaining After stroke) program was conceived to assess the effectiveness of these interventions in subacute stroke patients and to examine how the observed changes in sensori-motor functioning relate to changes in stroke recovery mechanisms associated with peripheral stiffness, interlimb interactions, and cortical inter- and intrahemispheric networks. The present paper describes the design of this single-blinded randomized clinical trial (RCT), which has recently started and will take several years to complete.</p> <p>Methods/Design</p> <p>Sixty patients with a first ever stroke will be recruited. Patients will be stratified in terms of their remaining motor ability at the distal part of the arm (i.e., wrist and finger movements) and randomized over three intervention groups receiving modified CIMT, modified BATRAC, or an equally intensive (i.e., dose-matched) conventional treatment program for 6 weeks. Primary outcome variable is the score on the Action Research Arm test (ARAT), which will be assessed before, directly after, and 6 weeks after the intervention. During those test sessions all patients will also undergo measurements aimed at investigating the associated recovery mechanisms using haptic robots and magneto-encephalography (MEG).</p> <p>Discussion</p> <p>ULTRA-stroke is a 3-year translational research program which aims (1) to assess the relative effectiveness of the three interventions, on a group level but also as a function of patient characteristics, and (2) to delineate the functional and neurophysiological changes that are induced by those interventions.</p> <p>The outcome on the ARAT together with information about changes in the associated mechanisms will provide a better understanding of how specific therapies influence neurobiological changes, and which post-stroke conditions lend themselves to specific treatments.</p> <p>Trial Registration</p> <p>The ULTRA-stroke program is registered at the Netherlands Trial Register (NTR, <url>http://www.trialregister.nl</url>, number NTR1665).</p

Bilateral motor unit synchronization is functionally organized.

To elucidate the neural interactions underlying bimanual coordination, we investigated in 11 participants the bilateral coupling of homologous muscles in an isometric force production task involving fatiguing elbow flexion and extension. We focused on changes in motor unit (MU) synchronization as evident in EMG recordings of relevant muscles. In contrast to a related study on leg muscles, the arm muscles did not exhibit MU synchronization around 16 Hz, consistent with our hypothesis that 16 Hz MU synchronization is linked to balance maintenance. As expected, bilateral MU synchronization was apparent between 8 and 12 Hz and increased with fatigue and more strongly so for extensor than for flexor muscles. MU synchronization in that frequency band is interpreted in terms of common bilateral input and substantiates the idea that common input is functionally organized. Since these findings are consistent with the literature on mirror movements, they suggest that both phenomena may be related. © 2006 Springer-Verlag