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PubMed2006

Predictive validity of five comorbidity indices in prostate carcinoma patients treated with curative intent.

BACKGROUND: Comorbidity is important to consider in clinical research on curative prostate carcinoma because of the role of competing risks. Five chart-based comorbidity indices were assessed for their ability to predict survival. METHODS: This was a case-cohort study of prostate carcinoma patient cohort treated with curative intent in Toronto and Southeast Cancer Care Ontario regions between 1990 and 1996; the subcohort was drawn from these men, whereas cases were cohort members who died from causes other than prostate carcinoma. Comorbidity data were obtained from medical charts (269 subjects). Vital status, age, area of residence, and socioeconomic status information were available. Predictive validity was quantified by the percent variance explained (PVE) over and above age using proportional hazards modeling. RESULTS: The Chronic Disease Score (CDS) (PVE = 11.3%; 95% confidence interval [95% CI], 3.5-22.8%), Index of Coexistent Disease (ICED) (PVE = 9.0%; 95% CI, 2.9-17.9%), Cumulative Illness Rating Scale (CIRS) (PVE = 7.2%; 95% CI, 1.4-17.1%), Kaplan-Feinstein Index (PVE = 4.9%; 95% CI, 0.6-12.8%), and Charlson Index (PVE = 3.8%; 95% CI, 0.3-10.9%) each explained some outcome variability beyond age. PVE differences among indices were not statistically significant. A comorbidity identified at the time of cancer diagnosis was the cause of death in 59.2% of cases (75% for cardiac or vascular causes). CONCLUSIONS: The better-performing, more comprehensive indices (CDS, ICED, and CIRS) would be useful in measuring and controlling for comorbidity in this setting. The CDS was easiest to apply and explained the most outcome variability.

Aged↗
PubMed2002

High numbers of granzyme B/CD8-positive tumour-infiltrating lymphocytes in nasopharyngeal carcinoma biopsies predict rapid fatal outcome in patients treated with curative intent.

This study determined whether tumour-infiltrating lymphocytes (TILs) in nasopharyngeal carcinomas (NPCs) include activated cytotoxic T lymphocytes (CTLs) and whether the numbers of activated CTLs in these biopsies are related to clinical outcome. Moreover, the study investigated whether the numbers of activated CTLs are associated with the expression of MHC class I proteins and the granzyme B antagonist PI-9 in the tumour cells. Forty-three Indonesian NPC patients (T(1-3), N(1-3), M(0)), who were treated with curative intent by radiotherapy only, were studied. Tumour-infiltrating activated CTLs were detected using antibodies against granzyme B, CD8, and CD56. Expression of MHC class I proteins and PI-9 was also determined by immunohistochemistry. Granzyme B-positive TILs were detected in all NPC biopsies. The presence of a high percentage (>25%) of granzyme B-positive TILs appeared to be a very strong predictor of a rapid fatal clinical outcome, independent of stage. Complete absence of MHC class I heavy chain expression in tumour cells was observed in 11 of 31 evaluable cases and low levels were observed in seven additional cases. No association between MHC class I expression and the numbers of granzyme B-positive TILs was observed. Expression of the granzyme B antagonist PI-9 in tumour cells was detected in three cases. It is concluded that the presence of many granzyme B-positive TILs in a selected group of Indonesian NPC patients is a strong and stage-independent marker for a rapid fatal clinical outcome.

Adult↗
PubMed2002

What do Swedish physiotherapists feel about research? A survey of perceptions, attitudes, intentions and engagement.

BACKGROUND AND PURPOSE: Although the past decades have witnessed an increase in physiotherapy research, there remains a concern about the translation of research into clinical practice, a problem that to date has attracted relatively limited interest. The aim of the present study was to investigate perceptions and attitudes toward research, intentions to perform as well as actual engagement in research-related activities in a sample of Swedish physiotherapists. METHOD: A cross-sectional design was used, and 343 Swedish physiotherapists responded to a postal questionnaire (representing a response rate of 61.7%). Questions about research-related activities were measured on a Likert-type scale, whereas questions referring to attitudes toward research used a semantic differential scale. RESULTS: The physiotherapists considered research as an important part of their professional role. Reading research literature was perceived as the most important research activity, and all mean attitude ratings were on the positive side of the scale. High workload and lack of time were the most commonly mentioned barriers to participation in research-related activities. Although Swedish physiotherapists read a large variety of journals, they most frequently read in their own language. CONCLUSIONS: The physiotherapists in this study were generally positive about research, which offers hope for an increased use of evidence-based practice in the future. In order to facilitate this development, easily accessible summaries could be provided. A cultural change within the profession, allowing more time for reading and discussing research reports should be encouraged.

Adult↗
PubMed2001

Intention-to-treat: methods for dealing with missing values in clinical trials of progressively deteriorating diseases.

Since it came up in the 1960s, the principle of intention-to-treat (ITT) has become widely accepted for the analysis of controlled clinical trials. In this context the question of how to perform such an analysis in the presence of missing information about the main endpoint is of major importance. Uncritical use of several ad hoc strategies for dealing with missing values is common in the practice of clinical trials. On the other hand, little is known about possible dangers and problems of applying these strategies. We therefore performed a detailed investigation of different methods for dealing with missing values in order to develop recommendations for their practical use. A simulation study was performed investigating possible consequences on type I error and power of applying different methods for dealing with missing values. The simulations were based on a clinical trial of osteoporosis, a progressively deteriorating disease. The strategies examined can be roughly classified into numerical imputation strategies (last observation carried forward, mean and regression based methods) and non-parametric strategies (rank and dichotomization based methods). Different drop-out mechanisms and different types of progression of disease are considered. The type I error increases drastically for the different strategies, especially if the courses of disease vary between treatment groups. The loss in power can be substantial. There is no strategy which is adequate for all different combinations of drop-out mechanisms, drop-out rates and courses of disease over time. For drop-out rates less than 20 per cent and similar courses of disease in the treatment groups, missing values might be replaced by the mean of the other group, or counted as treatment failures after dichotomization of the endpoint. For larger drop-out rates or less similar courses of disease, no adequate recommendations can be given. Because of the drastic consequences of increasing drop-out rates, it has to be a primary goal in clinical trials to keep missing values to a minimum. Unobserved information cannot be reliably regained by any methodological resources. As there are no strategies for universal use, reasons for the choice of a certain method have to be provided when designing and analysing clinical trials.

Computer Simulation↗
PubMed2005

A comparison of intent-to-treat and per-protocol results in antibiotic non-inferiority trials.

While the intent-to-treat (ITT) analysis is widely accepted for superiority trials, there remains debate about its role in non-inferiority trials. It is often said that the ITT tends to be anti-conservative in the demonstration of non-inferiority. This concern has led to some reliance on per-protocol (PP) analyses that exclude patients on the basis of post-baseline events, despite the inherent bias of such analyses. We compare ITT and PP results from antibiotic trials presented to the public at the FDA's Anti-infective Drug Advisory Committee from 1999 to 2003. While the number of available trials is too small to produce clear conclusions, these data did not support the assumption that the ITT would lead to smaller treatment difference than the PP, in the setting of antibiotic trials. Possible explanations are discussed.

Anti-Bacterial Agents↗
PubMed2006

The effects of non-compliance on intent-to-treat analysis of equivalence trials.

The standard approach for analysing a randomized clinical trial is based on intent-to-treat (ITT) where subjects are analysed according to their assigned treatment group regardless of actual adherence to the treatment protocol. For therapeutic equivalence trials, it is a common concern that an ITT analysis increases the chance of erroneously concluding equivalence. In this paper, we formally investigate the impact of non-compliance on an ITT analysis of equivalence trials with a binary outcome. We assume 'all-or-none' compliance and independence between compliance and the outcome. Our results indicate that non-compliance does not always make it easier to demonstrate equivalence. The direction and magnitude of changes in the type I error rate and power of the study depend on the patterns of non-compliance, event probabilities, the margin of equivalence and other factors.

Data Interpretation, Statistical↗
PubMed2006

Choosing the analysis population in non-inferiority studies: per protocol or intent-to-treat.

For superiority trials, the intent-to-treat population (ITT) is considered the primary analysis population because it tends to avoid the over-optimistic estimates of efficacy that results from a per-protocol (PP) population. However, the roles of the ITT population and PP population in non-inferiority studies are not clearly defined as in superiority trials. In this paper, a simulation study is conducted to systematically investigate the impact of different types of missingness and protocol violations on the conservatism or anticonservatism of analyses based on the ITT and the PP population in non-inferiority trials. We find that conservatism or anticonservatism of the PP or ITT analysis depends on many factors, including the type of protocol deviation and missingness, the treatment trajectory (for longitudinal study) and the method of handling missing data in ITT population. The requirement that non-inferiority be shown for both PP and ITT populations does not necessarily guarantee the validity of a non-inferiority conclusion and a sufficiently powered PP analysis is not necessarily powered for ITT analysis. It is important to assess the potential types and rates of protocol deviation and missingness that might occur in a non-inferiority trial and to obtain some prior knowledge regarding the treatment trajectory of the test treatment versus the active control at the design stage so that a proper analysis plan and appropriate power estimation can be carried out. In general, for the types of protocol violations and missingness considered, we find that hybrid ITT/PP analysis, which excludes non-compliant patients as in the PP analysis and properly addresses the impact of non-trivial missing data as in the MLE-based ITT analysis, is more promising by way of providing reliable non-inferiority tests.

Analysis of Variance↗
PubMed2000

Neural representation for the perception of the intentionality of actions.

A novel population of cells is described, located in the anterior part of the superior temporal sulcus (STSa, sometimes called STPa) of the temporal lobe in the macaque monkey. These cells respond selectively to the sight of reaching but only when the agent performing the action is seen to be attending to the target position of the reaching. We describe how such conditional selectivity can be generated from the properties of distinct cell populations within STSa. One cell population responds selectively to faces, eye gaze, and body posture, and we argue that subsets of these cells code for the direction of attention of others. A second cell population is selectively responsive to limb movement in certain directions (e.g., responding to an arm movement to the left but not to an equivalent leg movement or vice versa). The responses of a subset of cells sensitive to limb movement are modulated by the direction of attention (indicated by head and body posture of the agent performing the action). We conclude that this combined analysis of direction of attention and body movements supports the detection of intentional actions.

Animals↗
PubMed1999

Communicative intentions and language: evidence from right-hemisphere damage and autism.

In this review article, it is argued that the wide range of communicative deficits that have been noted in both individuals with damage to the right cerebral hemisphere (RHD) and high-functioning individuals with autism may stem from difficulties appreciating the importance of their interlocutor's communicative intentions (CIs). It is also argued that the abnormal semantic development noted in infants with RHD and autism may be related to difficulties in appreciating CIs as well. Finally, it is suggested that the CIs hypothesis may provide an avenue for integrating a number of theoretical suggestions that have been made regarding the right hemisphere's contributions to communicative competence.

Adult↗
PubMed2002

Libet's research on the timing of conscious intention to act: a commentary.

S. Pockett (Consciousness and Cognition, this issue) and G. Gomes (Consciousness and Cognition, this issue) discuss a possible bias in the method by which Libet's subjects estimated the time at which they became aware of their intent to move their hands. The bias, caused by sensory delay processing the clock information, would be sufficient to alter Trevena and Miller's (Consciousness and Cognition, this issue) conclusions regarding the timing of the lateralized readiness potential. I show that the flash-lag effect would compensate for that bias. In the last part of my commentary I note that the other target articles do not examine the most interesting aspect of Libet's unfashionable views on free will. I point out that Libet's views are less strange than they at first appear to be.

Consciousness↗
PubMed2000

Dissociating automatic and intentional processes in children's eyewitness memory.

Two experiments investigated the contribution of automatic and intentional memory processes to 5- and 8-year-old children's acceptance of misinformation. Children were presented with a picture story followed by misleading postevent details that either were read to participants or were self-generated in response to semantic and perceptual hints. Children were then given a recognition test under 2 instructional conditions. In the inclusion condition children reported whether they remembered items from either of the previous phases. In the exclusion condition children were instructed to exclude postevent suggestions. Children were more likely to accept misled-generate items compared to misled-read items in the inclusion condition, but the opposite was the case under exclusion instructions. Both automaticity and recollection (cf. L. L. Jacoby, 1991) influenced misinformation acceptance, but the role of automatic processes declined with age.

Age Factors↗
PubMed2002

Putting intentions into cell biochemistry: an artificial intelligence perspective.

The living cell exists by virtue of thousands of nonlinearly interacting processes. This complexity greatly impedes its understanding. The standard approach to the calculation of the behaviour of the living cell, or part thereof, integrates all the rate equations of the individual processes. If successful extremely intensive calculations often lead the calculation of coherent, apparently simple, cellular "decisions" taken in response to a signal: the complexity of the behavior of the cell is often smaller than it might have been. The "decisions" correspond to the activation of entire functional units of molecular processes, rather than individual ones. The limited complexity of signal and response suggests that there might be a simpler way to model at least some important aspects of cell function. In the field of Artificial Intelligence, such simpler modelling methods for complex systems have been developed. In this paper, it is shown how the Artificial Intelligence description method for deliberative agents functioning on the basis of beliefs, desires and intentions as known in Artificial Intelligence, can be used successfully to describe essential aspects of cellular regulation. This is demonstrated for catabolite repression and substrate induction phenomena in the bacterium Escherichia coli. The method becomes highly efficient when the computation is automated in a Prolog implementation. By defining in a qualitative way the food supply of the bacterium, the make-up of its catabolic pathways is readily calculated for cases that are sufficiently complex to make the traditional human reasoning tedious and error prone.

Animals↗
PubMed2000

Movement and mind: a functional imaging study of perception and interpretation of complex intentional movement patterns.

We report a functional neuroimaging study with positron emission tomography (PET) in which six healthy adult volunteers were scanned while watching silent computer-presented animations. The characters in the animations were simple geometrical shapes whose movement patterns selectively evoked mental state attribution or simple action description. Results showed increased activation in association with mental state attribution in four main regions: medial prefrontal cortex, temporoparietal junction (superior temporal sulcus), basal temporal regions (fusiform gyrus and temporal poles adjacent to the amygdala), and extrastriate cortex (occipital gyrus). Previous imaging studies have implicated these regions in self-monitoring, in the perception of biological motion, and in the attribution of mental states using verbal stimuli or visual depictions of the human form. We suggest that these regions form a network for processing information about intentions, and speculate that the ability to make inferences about other people's mental states evolved from the ability to make inferences about other creatures' actions.

Adult↗
PubMedDate not supplied

On the relations among priming, conscious recollection, and intentional retrieval: evidence from neuroimaging research.

Neurobiological distinctions among forms of memory have been investigated mainly from the perspective of lesion studies in nonhuman animals and experiments with human neurological patients. We consider recent neuroimaging studies of healthy human volunteers using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) that provide new information concerning the neural correlates of particular forms of memory retrieval. More specifically, we consider evidence indicating that priming, a form of implicit retrieval, is associated with decreased activity in various cortical regions. We also consider evidence suggesting that two components of explicit retrieval-intentional or effortful search and successful conscious recollection-are preferentially associated with increased activity in prefrontal and medial temporal regions, respectively.

Brain↗
PubMed1986

Non-intentional motor vehicle-related carbon monoxide deaths-revisited.

A study of non-intentional, motor vehicle-related, carbon monoxide-related deaths was performed on the case files of the Office of the Medical Examiner of Metropolitan Dade Country in Miami, FL (USA) during the years 1980-1984. A total of 15 cases were collected during that time period. These are presented in some detail. A discussion ensues that compares the similar circumstances of these cases, notably running the engine of an automobile in an enclosed space, with older reports in the literature which emphasized defective vehicle exhaust systems as the leading etiology for these deaths.

Accidents↗
PubMed1989

An assessment of the existence of muscle synergies during load perturbations and intentional movements of the human arm.

A cross-correlation analysis was performed on EMG activities in elbow and shoulder flexors evoked by force perturbations acting in different directions on the forearm and during intentionally generated movements with the purpose of characterizing the temporal relationships between patterns of activation of different muscles. Qualitatively it was found that the shape of the cross-correlation function differed from one experimental condition to the next. A principal component analysis permitted a quantitative assessment of this point. In general it was found that two principal components could account for the data. Furthermore when the cross-correlograms are represented in principal component space, there was no clustering of the data points. Several possible definitions of 'muscle synergies' are discussed from the perspective of this finding. It is concluded that the most restrictive definition is incompatible with the data. Less restrictive definitions, while compatible with the data, do not lead to a simplification of the control problem.

Arm↗
PubMed1988

Intentions to use predictive testing by those at risk for Huntington's disease: implications for prevention.

Huntington's disease (HD) is a late onset, genetic disorder that is incurable and undetectable until the onset of symptoms. A marker for the gene that causes HD was recently discovered which will lead to a predictive test. The purpose of this research was to assess the knowledge, attitudes, beliefs, and behavioral intentions concerning the impending predictive test by those at risk for HD. Results indicated that a majority of participants favored using the test presymptomatically and would encourage their adult children to use it as well. Fewer participants favored using the predictive test prenatally or on minors. Characteristics that best differentiated those who intend and do not intend to use predictive testing were identified and discussed. Suggestions for interventions were presented with an emphasis on outreach and prevention programs designed to prepare HD families for the difficult decisions the predictive test will precipitate and the subsequent impact of those decisions.

Adult↗
PubMed1993

Mental illness and the mind-brain problem: delusion, belief and Searle's theory of intentionality.

Until recently there has been little contact between the mind-brain debate in philosophy and the debate in psychiatry about the nature of mental illness. In this paper some of the analogies and disanalogies between the two debates are explored. It is noted in particular that the emphasis in modern philosophy of mind on the importance of the concept of action has been matched by a recent shift in the debate about mental illness from analyses of disease in terms of failure of functioning to analyses of illness in terms of failure of action. The concept of action thus provides a natural conduit for two-way exchanges of ideas between philosophy and psychiatry. The potential fruitfulness of such exchanges is illustrated with an outline of the mutual heuristic significance of psychiatric work on delusions and philosophical accounts of Intentionality.

Biological Psychiatry↗