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Biomedical subjects

J Ridderikhoff

Publications and source records attributed to J Ridderikhoff.

13 recordsLinked to original sources
PubMed2001

Hip problems in older adults: classification by cluster analysis.

No validated classification system of hip disorders in primary care is available. This study explores whether it is possible to obtain such a classification with the method of cluster analyses. A total of 224 consecutive patients aged 50 years or older, consulting the general practitioner for pain in the hip region, and referred for X-ray investigation of the hip, underwent a standardized examination. Ward's cluster analysis with variables from history and physical examination of the hip region resulted in a classification with nine different clusters. These clusters were reproduced in 10 random subsamples and with an alternative cluster analysis. Significant relationships of various external variables (radiological and sonographic signs and variables of low-back and knee examination) with the distinctive clusters were found. Twenty of the approached experts recognized the symptoms in seven clusters as identifiable syndromes. However, further validation of the achieved classification system, especially with respect to the clinical importance, is needed before introducing it into clinical practice.

Cluster Analysis↗
PubMed1999

Who is afraid of the system? Doctors' attitude towards diagnostic systems.

Although physicians indicate a need for diagnostic support, devices that may provide such support, i.e. computer-aided systems are not in widespread use. Practising physicians often blame this on the computer. We have tested this idea by asking physicians to solve a number of patient problems with the help of a diagnostic decision support system in a realistic environment. As we expected, the use of the computer was not found to be an obstacle. However, the support part of the system, which was meant to stimulate the user's thoughts and to prompt him to review his conclusions, turned out to be problematic. The critiquing function of the system hardly seemed appreciated by the participants, and only rarely influenced their diagnostic judgement. Sources of additional information were ignored. We have come to the conclusion that the combination of physicians and computer-aided diagnosis deserves further and thorough exploration.

Adult↗
PubMed1998

The diagnosis of allergic rhinitis: how to combine the medical history with the results of radioallergosorbent tests and skin prick tests.

OBJECTIVE: To identify the most useful combinations of symptoms and the results of radioallergosorbent tests (RASTs) and skin prick tests (SPTs) for the diagnosis of allergic rhinitis. DESIGN: A prospective comparison was made of symptoms and the results of RASTs and SPTs with 7 different nasal allergies; the references used were the "consensus diagnoses" provided by 3 experts. SETTING: Nineteen general practices in The Netherlands. PATIENTS: 365 consecutive patients aged 12 or over who visited their general practitioner because of chronic or recurrent nasal symptoms between 1 March 1990 and 1 March 1991. MAIN OUTCOME MEASURES: The most useful combinations of items from the history, RASTs, and SPTs, for the diagnosis of 7 different nasal allergies; the predictive probabilities of these combinations. RESULTS: Diagnostic criteria could be drawn up resulting in a near-perfect discrimination between patients diagnosed as having allergic rhinitis and patients diagnosed as not having allergic rhinitis. Most of these criteria combined only a single item from the history with either RAST or SPT. For nearly all nasal allergies, both the negative predictive probabilities and the positive predictive probabilities were 97% or more. CONCLUSIONS: The common nasal allergies can be diagnosed with a very high certainty with the aid of simple diagnostic criteria. Data from a strictly limited case history combined with either RAST or SPT are sufficient.

Adolescent↗
PubMed1998

Comparison between two devices for measuring hip joint motions.

OBJECTIVE: To compare the reliability of measurements of hip motions obtained with two instruments, an electronic inclinometer and a two-arm goniometer, and to investigate whether the two instruments, and different body positions, produce the same measurement data. METHODS: Maximal active and passive hip movements were measured simultaneously with both instruments, in nine subjects during 10 consecutive measurements at short intervals. RESULTS: Intra-observer variability was lower with the inclinometer in measurements of passive hip rotations. The two instruments showed equal intra-observer variability for hip movements in general. The inclinometer showed lower inter-observer variability in the measurements of active internal rotation. More rotational movement was measured with the two-arm goniometer; more extension and flexion with the inclinometer. Also, more rotational movement was found in the prone position compared to sitting and supine positions. CONCLUSIONS: The inclinometer is more reliable in measurements of hip rotation. For hip movements in general the two-arm goniometer is just as accurate when used by only one observer. The two instruments, and some positions, are not interchangeable during consecutive measurements.

Adult↗
PubMed1997

[Cluster headache: misjudged because unknown].

Cluster headache is a rare but very typical disease. Too often, however, the correct diagnosis is made only after several years of patient suffering, while adequate treatment is readily available. Two patients, men aged 29 and 45 years, showed a good picture of the typical features: excruciating, unilateral headache occurring in attacks and associated among other aspects with conjunctival redness, swelling of nasal mucosa and motor restlessness.

Adult↗
PubMed1997

A diagnostic support system in general practice: is it feasible?

A medical diagnostic decision support system (DDSS) has been developed for and tested in general practice. Two major issues have been addressed: diagnostic support and usefulness. The diagnostic support pertains to the ability of the system to generate diagnostic hypotheses from a set of patient data. The usefulness is approached by creating a computer system which can be used simultaneously with the doctor-patient consultation. The support function operates by matching symptoms from the patient data base with symptom configurations contained in the knowledge base. The support is presented as a list of diagnostic hypotheses ranked by degree of concordance. A user-friendly interface has been constructed with a comprehensive set of clinical terms within which the doctor can locate a desired symptom and store it with a single keystroke. With another keystroke the doctor can check the stored data and ask for support at any moment during the process. The overall purpose is to invite the doctor to rethink and re-examine his steps and to reconsider possible alternatives in the light of the presented diagnostic information. In our view it has to be the doctor who makes the final judgement. A test with the system in general practice revealed good performance of the system and an astonishing proficiency of the participating doctors in its use during the consultation. Twenty doctors solved five patient cases, entering 2000 clinical items within acceptable limits of consultation time. In 96% of the cases the correct diagnosis appeared in the differential diagnosis list. The doctors' diagnostic accuracy was 43%. The use of standardised terminology as an option for further development is discussed. The role of the doctor in computer-aided diagnostics remains open to debate. A computer-aided diagnostic support system in general practice appears to be feasible.

Adult↗
PubMed1996

Nasal smear eosinophilia for the diagnosis of allergic rhinitis and eosinophilic non-allergic rhinitis.

OBJECTIVE: To evaluate nasal smear eosinophilia for the diagnosis of allergic rhinitis and eosinophilic non-allergic rhinitis in general practice. DESIGN: Nasal smear eosinophilia was assessed and compared with 'consensus diagnoses' made by three experts in a modified Delphi method. SETTING: Nineteen general practices in The Netherlands. SUBJECTS: 363 consecutive patients aged 12 years or over who visited their general practitioner because of chronic or recurrent nasal symptoms between 1 March 1990 and 1 March 1991. MAIN OUTCOME MEASURES: The predictive value of nasal smear eosinophilia for allergic rhinitis; the prevalence of eosinophilic non-allergic rhinitis. RESULTS: The positive predictive value of nasal smear eosinophilia (> or = 10% eosinophils) for allergic rhinitis was 30/37 = 81% (95% confidence interval (CI): 65-92%), the negative predictive value 172/312 = 55% (95% CI: 50-61%). Addition of the result of nasal smear eosinophilia to the information that was already obtained from the medical history resulted in a significant but very small improvement in the discrimination between patients with and without allergic rhinitis. The prevalence of eosinophilic non-allergic rhinitis was 7/349 = 2.0% (95% CI: 0.8-4.1%). CONCLUSION: Nasal smear eosinophilia contributes significantly to the diagnosis of allergic rhinitis; however, this contribution is very small and considered clinically irrelevant. Eosinophilic non-allergic rhinitis has a low prevalence; identifying this disorder is of minor importance. In conclusion, nasal smear eosinophilia is not recommended for use in general practice.

Adolescent↗
PubMed1994

The Phadiatop test compared with RAST, with the CAP system; proposal for a third Phadiatop outcome: "inconclusive".

In 19 general practices, blood samples were obtained from 361 patients aged 12 years or older with chronic nasal symptoms. The Phadiatop test and a panel of RASTs to common inhalant allergens were performed on all sera with the recently introduced Pharmacia CAP system. The RAST panel was accepted as the standard. The sensitivity of the Phadiatop was 94% (95% confidence interval (CI): 89-97%), the specificity 98% (95% CI: 95-99%), the positive predictive value 97% (95% CI: 94-99%), and the negative predictive value 95% (95% CI: 91-98%). It is noteworthy that these values are very similar to those found in hospital outpatient departments. It was possible to reduce further the small percentage of false outcomes by replacing the cutoff point of the Phadiatop ratio of 1.00 by the two cutoff points 0.75 and 1.15. This resulted in three possible outcomes: a highly predictive positive outcome, a highly predictive negative outcome, and an "inconclusive" outcome. Alternatively, the cutoff point of 1.00 may be maintained while attaching the annotation "borderline" to all positive or negative Phadiatop outcomes where the Phadiatop ratio is between 0.75 and 1.15. By this simple method, physicians are alerted to the possibility of a false outcome; on the basis of the case history and other clinical findings, they can then decide whether further testing should be done.

Administration, Inhalation↗
PubMed1993

Problem-solving in general practice.

OBJECTIVE: To identify problem solving strategies in general practice. BASIC PROCEDURES: Three styles of scientific reasoning were defined and modelled on the medical environment. These models were tested in a simulated doctor-patient encounter. MAIN FINDINGS: According to the definitions contained in the models a deductive or hypotheticodeductive strategy could not be discovered. All participants used exclusively the inductive method and, more specifically, the speculative variant. This variant may be best described as a process of iterative pattern recognition. CONCLUSIONS: The manifest utilization of the inductive method carries many implications among which are the irretraceability and irreproducibility of the process. The speculative form approaches the conception of art rather than science. This is exactly what most doctors try to tell: medicine is an art. The strategy allows for flexibility and quick response to the patient's needs.

Adult↗
PubMed1993

Information exchange in a patient-physician encounter. A quantitative approach.

The efficiency of data acquisition in a patient-physician encounter was investigated. In a simulation study, in which 60 family physicians and eight internists participated, the patient was replaced by an actor who used a structured set of patient data. The simulation model proved to be quite natural; data acquisition was primarily influenced by the amount of time available. Discerning between overall and diagnostic information, conclusions could be drawn on the effectiveness of data acquisition. Under time pressure, physicians tend to look for broadly defined symptoms rather than for details of the patient's illness. The collection of patient data then has an inquisitive character, having implications for the quality of clinical judgement. The physician's capabilities in eliciting relevant information from a patient appear to be of crucial importance for clinical problem-solving. The present study shows that patient-physician interviewing is effective insofar it concerns broad descriptions, but ineffective in eliciting specific data. If interviewing is laborious and time-consuming this may, therefore, affect the kind of information to be collected.

Communication↗
PubMed1991

Medical problem-solving: an exploration of strategies.

In contrast to factual knowledge the reasoning processes of doctors in their attempts to clarify the patient's problem has been a somewhat neglected domain of study. The rise of experimental psychology, clinical decision analysis, and problem-based learning fostered studies in this area. Several studies from different viewpoints have been performed, leading to a more profound understanding of these processes. I approached the issue from a general physician viewpoint which reverted to the old distinction between deductive and inductive reasoning. Within a group of 68 participating doctors (family doctors and general physicians) the inductive method was exclusively employed. From this finding we conjecture that the inductive type of reasoning is the predominant style in the medical world. The consequences as attached to the overall utilization of the inductive method are far-reaching. Among others, process retracing as a feedback mechanism fails to function when it results from the intuitive nature of the (pattern-recognition) process. As a consequence we do not and can not know what we may learn from experience, good things as well as bad things. The inductive method is a method of practice and quick reaction, but it leaves us empty-handed as far as understanding and teaching are concerned.

Diagnosis↗