Warren S. Torgerson

Subjective Structures and Operations in Semantic Memory.

Abstract Relations of semantic distance to response latencies in similarity judgments, to reaction times in a same-different classification task, and to proximity of recall in a free recall task were investigated. A multidimensional analysis of the similarity judgments was used to determine semantic structure and distances for pairs of animal words chosen from three classes:mammals, birds, andfish. A four-dimensional structure revealed both the class and quantitative contributions to the similarity ratings. Semantic distances were directly related to response latencies for words from the same class and inversely related for words from different classes. Distances were also related to reaction times for “same” judgments in the classification task, but not for “different” judgments. Independent ratings of typicality did not improve the relationship. Semantic distance was also a good predictor of proximity of recall for mammals, less so for birds, and not at all for fish.

A validated, practical classification procedure for many persistent low back pain patients

&NA; We have developed a simple procedure for assigning persistent low back pain patients to one of four mutually exclusive, hierarchically organized classes. The procedure relies on the spatial distribution of a patients pain and the results of straight leg raise tests to make the assignment. We have applied the procedure to a large group of patients who sought treatment for persistent LBP at several university affiliated tertiary care clinics, and found that the resulting four classes of patients were significantly different from one another in their presentation, and in the way they were evaluated and treated by physicians. We concluded that the procedure may have practical research and clinical applications.

Persistent low back pain and sciatica in the United States: treatment outcomes.

Patients with persistent low back pain (LBP) appear to be different in several important ways from patients who have traditionally been classified as patients with acute or chronic LBP, and data on the effectiveness of the treatments prescribed for them are lacking. The aim of the current study was to evaluate the short- and long-term effectiveness of the treatments currently prescribed for these patients. The data reported in this article were gathered as part of a multicenter, prospective, cross-sectional study of patients who were treated for persistent LBP by neurologic and orthopedic surgeons who are recognized specialists in spinal disorders. At enrollment, patients completed a baseline evaluation, and their physicians recorded relevant clinical and treatment data on standardized study forms. At 3, 6, 12, and 24 months after treatment, patients completed follow-up evaluations. Patients were divided into five treatment groups, and effectiveness was evaluated separately for each group using five patient-reported measures of outcome: pain severity, functional disability, psychologic distress, physical symptoms, and health care use. The data revealed that at the 2-year follow-up, the typical patient of the no-treatment group had improved slightly in terms of pain severity and health care use, but had experienced little or no improvement in functional disability, physical symptoms, and psychologic distress. The average patient in the conservative care group reported small improvements in pain severity, functional disability, physical symptoms, and health care use, with no change in psychologic distress. These small improvements occurred within the first 3 months after enrollment, with essentially no change thereafter. The average patient in the immediate surgical care group showed substantial improvement on all of the outcome measures. The observed improvements were evident shortly after treatment and were maintained for the duration of the study. Patients in the delayed surgical care group had outcomes that were less dramatic than those observed in the immediate surgery care group, but greater than those observed in the conservative care group. The patients who were treated surgically by physicians outside the study, outside surgical care group, did not improve over time. Patients with persistent LBP who received no treatment showed no spontaneous recovery. Conservative care treatments prescribed by surgeons who specialize in spinal disorders, did not appear to be any more effective than no treatment. The outcome of surgery for persistent LBP varied from dramatic for one subgroup of surgical patients, to poor for another subgroup of patients. Patients who were selected immediately for surgical treatment improved substantially. Those treated surgically later by study physicians or by physicians not associated with the study fared less well.

Diminished reactivity of postmature human infants to sucrose compared with term infants

Sucrose is an effective calming and analgesic agent in infant humans, and characteristics of this calming effect suggest it may occur through an opioid pathway. Implications of this would be that infants who have experienced chronic prenatal stress and concomitantly elevated levels of endogenous opioids resulting in tolerance should therefore be less responsive to sucrose than nonstressed infants. To test this, we compared healthy term infants (M = 39 weeks 3 days) and chronically stressed, postmature infants (M = 42 weeks) with respect to the sucrose-mediated calming effect at 5-91 hr of age

Varieties of pain

VARIETIES OF PAIN. W.S. Torgerson’ and M,_Be_DD_e_b_b_a_, and K.J. Mason’, Dept. of Neurosurgery, The Johns Hopkins School Of Medicine, Baltimore, MD, 21205, USCI. In 1971, Melzack and Torgerson proposed a tentative system for specifying the relationships between the meaning of words people use to describe the qualities of experienced pain. The system represents each word by its membership in one of 16 mutually exclusive classes, with the classes grouped into three major domains: sensory, affective, and evaluative. Direct judgments of the similarities of pains described by pairs of descriptors reveal some serious inadequacies in the classification system. In 1984, Torgerson and BenDebba proposed an alternative system where each word is characterized by its proximity to several ideal pain types. CI mathematical model was developed to identify the underlying ideal types and the proximity of each descriptor to each ideal type, from data consisting of similarity judgments between pairs of descriptors. Several overlapping similarity judgment studies have been completed. The data have been analyzed using the proposed model and the data fit the model very well. The results of the individual studies were combined to obtain an overall structure for all 102 descriptors from the original Melzack Torgerson list. The obtained structure specifies each word in terms of its value on a common intensity dimension and its proximity to each recovered ideal type. The intensity dimension corresponds closely to Melzack-Torgerson evaluative dimension. The recovered ideal types form to relatively distinct subgroups, one related to the sensory domain of the Melzack-Torgerson system and the other to the affective domain. The obtained structure and its implication for the assessment of clinical pain will be discussed.

A non-parametric test of correlation using rank orders within subgroups

Kendalls rank order test for association between two variables is generalized to the case where the total sample is made up of several subgroups and the data on one or both variables consist of the rank order within each subgroup. The test involves no assumptions concerning scales of measurement, shapes of distributions, or relative level of excellence or amount of variability of the different subgroups. Two empirical examples indicate that the normal approximation to the exact test of significance can be considered adequate for most practical situations. Special consideration is given to the case of tied ranks. If ties occur in but one variable within any given subgroup, only a slight modification in procedure is needed. Extensive ties in both variables within subgroups lead to difficulties in determining the appropriate correction for continuity.

SCALING AND PSYCHOMETRIKA: SPATIAL AND ALTERNATIVE REPRESENTATIONS OF SIMILARITY DATA

Progress over the past twenty-five years in the development and improvement of models for representation of similarity data is reviewed. The discussion includes comments on class, dimensional, ideal type, and dichotomous attribute representations of underlying similarity structures. Most of the theoretical research in the area appeared, and continues to appear, inPsychometrika.

How hyperstereopsis can improve the accuracy of spatial perception: an experimental approach

It has been shown that people consistently underestimate distances between objects in the depth direction as compared to the lateral direction. This study examined the use of artificially enhanced stereopsis (hyperstereopsis) in judging relative distances. The data showed that doubling interocular distance by means of a telestereoscope reduced the illusory compression of depth: subjects who viewed the scene without the telestereoscope averaged a depth compression of 0.28. Subjects who used the telestereoscope yielded an average compression of 0.40. Individual verbal self-reports of depth compression effects were unreliable, pointing out the value of quantitative experimental methods.

Relationship between pain report and diagnosis in women with dysuria

Dysuriar or painful urination, is a symptom common to infections of the urinary tract and the genital tract. In the absence of a pelvic examination, traditional symptom informat ion and genera1 physical findings cannot distinguish between the different sites of infection. Previous studies have suggested that a distinction can be made on the basis of reported pain. We have recently developed methods for assessing the multiple components of dysuric pain, and applied them to 120 consecutive women presenting with dysuria. Our aim was to determine whether urinary and genital tract infections can be distinguished when detailed information on pain is added to traditional genito-urinary symptom information.

A model for evaluating treatment outcomes in low back pain

tance to injections and decreased compliance of the epidural space at the particular site of injection. Pain levels were consistently raised to higher levels on repeated incremental injections and progressively decreased with local anesthetics. Activity levels also increased fallowing local anesthetic injections. Conclusions: The use of electric stimulation identifies the epidural space and more im-portantly, the site of the injection. The caudal approach is advantageous since it provides