Diagnosis of hip fracture by the auscultatory percussion technique.

Traumatic hip pain is a commonly encountered complaint in the emergency department. Occasionally, initial radiographs fail to show a fracture. A delayed diagnosis can result in significant patient morbidity. Diagnostic algorithms have been formulated to evaluate the patient with hip pain and negative initial radiographs. The auscultatory percussion technique can alert the physician of the presence or absence of an occult hip fracture. Consequently, the physician may order a more sophisticated imaging technique.

Misunderstanding between knowledge engineers and domain experts: a re-evaluation of the use of induction for medical expert systems.

The effectiveness of an induction algorithm for making decisions was investigated using a complete set of diagnoses and corresponding outcomes for all possible distinct cases of thyroid disorders. Investigation of both diagnoses and outcomes followed a late discovery of a misunderstanding between the knowledge engineers and the expert. The knowledge engineers had erroneously equated the expert's terms 'diagnosis' and 'outcome'. Following this discovery, two previously reported induced expert systems were re-evaluated using the more appropriate 'outcomes' and were found to be correct for 79 and 70% of all cases.

Comparison of smoking habits between patients with surgically confirmed herniated lumbar and cervical disc disease and controls.

There have been numerous studies that implicate cigarette smoking as a risk factor for the development of back pain or disc disease. The purpose of this article is to review patients who underwent surgery for cervical or lumbar radiculopathy and to investigate the relationship between cigarette smoking and development of surgical disc disease. A cigarette smoking study of 205 surgical patients with lumbar and cervical disc diseases was done, with the surgical patients compared to 205 age-sex-matched inpatient controls during 1987-1988. This study was conducted at the Pennsylvania Hospital in Philadelphia, Pennsylvania. There were 163 patients with lumbar disc disease and 42 patients with cervical disc disease. The ratio of men to women was 1.5:1 for lumbar disc and 2.5:1 for cervical disc disease. Smoking history (current and ex-smokers) was strikingly increased in both prolapsed lumbar intervertebral disc (56% vs. 37% of controls, p = 0.00029) and cervical disc disease (64.3% vs. 37% of controls, p = 0.0025). Calculated relative risks for smokers were 2.2 for lumbar disc and 2.9 for cervical disc diseases. This association between cigarette smoking and disc disease was more significant when comparing between current smokers versus nonsmokers (p = 0.000011 for lumbar disc disease, and p = 0.00064 for cervical disc disease). Relative risks for current smokers were 3.0 for lumbar disc and 3.9 for cervical disc diseases. This correlation was significant for both males (p = 0.000068 for lumbar disc disease, p = 0.043 for cervical disc disease) and females (p = 0.018 for lumbar disc disease, p = 0.006 for cervical disc disease).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the use of induction in the development of a medical expert system.

In an earlier study, two medical expert systems for diagnosing thyroid disorders, developed by the application of induction on a sample of previously diagnosed cases and on expert-generated rules, diagnosed a set of test cases better than an expert system developed by the more traditional method of collaboration between a knowledge engineer and an expert. In this paper, an alternative measure of the accuracy of diagnosis of each system is used to evaluate the systems. Diagnoses for every distinct case represented by a combination of indicating factors are compared with diagnoses that the expert made. The induced systems provide diagnoses for many more distinct cases, but a much higher proportion of these diagnoses are incorrect. It is argued that generalizing to unseen cases is an inappropriate use of induction algorithms. The systematic development of a decision table is a more appropriate method for devising a medical expert system.

Comparing two objects for size after a comparison of one of the objects with other objects.

When shown the names of two objects, subjects determine which object is larger more slowly as the difference in the sizes of the objects decreases. This might result from variations in the time taken to access sufficient information to perform the task; information which crudely specifies size is accessed first and can be used when the sizes differ greatly; information which specifies size on a more finely graded scale must be accessed when they do not. This hypothesis was tested. Subjects shown the names of three objects, determined which object was intermediate in size. Immediately thereafter the name of another object was shown, the task then being to decide whether the object previously judged intermediate was larger than this object. In this second task reaction times increased with decreasing differences in size between the two objects; this increase was smaller, however, when the sizes of the objects in the first task were similar. The results were predicted from the assumption that when the specification of an object's size in terms of fine discrimination is accessed for comparison in the first task it remains available for use in the second task; thus the time normally required for accessing that information in the second task is reduced. Some implications of the results are discussed.