Biomedical subjects
Publications and source records attributed to C S Stohler.
A hand-held, servo-controlled tissue palpation device (SCPD) was developed to measure the pressure-pain characteristics of human tissue for disease states linked to altered pressure-pain sensitivity. The design was based on an adaptive controller using force feedback to reach and maintain a desired force in spite of movements of the operator's hand holding the device or positional changes of the subject.
The endogenous opioid system is involved in stress responses, in the regulation of the experience of pain, and in the action of analgesic opiate drugs. We examined the function of the opioid system and mu-opioid receptors in the brains of healthy human subjects undergoing sustained pain. Sustained pain induced the regional release of endogenous opioids interacting with mu-opioid receptors in a number of cortical and subcortical brain regions. The activation of the mu-opioid receptor system was associated with reductions in the sensory and affective ratings of the pain experience, with distinct neuroanatomical involvements. These data demonstrate the central role of the mu-opioid receptors and their endogenous ligands in the regulation of sensory and affective components of the pain experience.
No general agreement exists regarding the effect that bolus size has on masticatory movement, probably because both the size and texture of food change during mastication. In this experiment, in order to clarify the effect of bolus size on masticatory movement, a food that does not change in size and texture--chewing gum--was chosen, and the relationship between bolus size and the chewing cycle was analyzed. Ten healthy subjects in their twenties were asked to chew pieces of softened chewing gum of four different sizes. For ten cycles, beginning with the fifth cycle of mastication, gape and masticatory width were calculated for the spatial parameter of the chewing cycle, and cycle time was calculated as the temporal parameter. The relationship between these parameters and the bolus size was investigated. As the bolus size increased, the spatial and temporal parameters increased. In addition, there was a positive correlation between the bolus size and each parameter. The influence of the bolus size was as follows: gape, r = 0.91; masticatory width, r = 0.79; and cycle time, r = 0.74 (all, P < 0.001). From these results it was concluded that the shape of the chewing cycle was altered by the size of the food bolus, and that the changes in sensory input from the peripheries greatly affected the masticatory movement.
Neurokinin-1 receptor and mu-opioid receptor agonists affect respiratory rhythm when injected directly into the preBötzinger brainstem complex, which is the hypothesized site for respiratory rhythmogenesis in mammals (Science 286 (1999) 1566). Early stress-induced analgesia (SIA) is naloxone-insensitive and as such considered independent of the activation of the mu-opioid system. Prolonged application of electrical shocks, however, produces analgesia that is mediated by the mu-opioid system (Science 208 (1980) 623). Together these findings suggest that any early pain-specific increased respiration should be attenuated in the tonic state of pain. Ten healthy, pain-free female volunteer subjects participated in this experimental study involving deep acute and tonic pain. The experimental design included three conditions: (1) baseline; (2) pain; and (3) a placebo control stimulus. Experimental pain was induced by the infusion of hypertonic saline into the masseter muscle. Infusion of isotonic saline in the contralateral masseter was used as a control. Blinded subjects were randomly assigned to a particular sequential order of the experimental stages, i.e. hypertonic saline infusion preceded the isotonic saline infusion or vice versa. Respiration rate, mean peak inspiratory and expiratory flow rates, and the minute ventilation volume quantified breathing. Results indicate that effects on respiration were pain-specific and that the early effects on respiration were significantly attenuated in sustained pain. In the early stage of pain, all monitored variables (respiration rate, minute ventilation volume, and inspiratory and expiratory flow rates) were elevated to statistically significant degrees when compared to measurements taken at baseline or during control infusion. Only respiration rate continued to be significantly elevated in sustained pain. We concluded that rhythmogenic neurons in the preBötzinger brainstem complex appear as the likely target for pro-nociceptive and anti-nociceptive input, explaining both the observed initial facilitation and subsequent habituation of respiration in early and sustained pain.
Conditions involving chronic orofacial pain represent a major health problem, and patients with persistent pain are difficult to manage successfully. These conditions are often comorbid with additional health issues such as sleep disturbances, cardiovascular, gastrointestinal and reproductive system complaints, weight loss or weight gain, swelling, numbness, sweating and flushing, and concerns regarding loss of libido, drive, attention, and memory. Neuroendocrine and autonomic pain-stress responsivity and the consequences of pain for sensory, motor, immune and reproductive functions, and mood seem to account for the broad range of comorbid complaints. Susceptibility to a particular response appears to explain intra-individual differences in disease expression. Understanding of these regulatory, mostly adaptive processes will support novel treatments to manage many troublesome comorbid complaints for which current approaches are unsatisfactory.
AIMS: To determine the degree to which the generic pain intensity rating (i.e., overall and without reference to a particular body site) of facial pain patients being seen in a specialty setting for facial pain is influenced by painful comorbidity in body parts other than the face. METHODS: In this prospective study, 40 consecutive female temporomandibular pain patients rated their generic pain on a 100-mm visual analog scale. After marking all painful body sites on pain drawings, patients were asked to rate the pain intensity for each of the indicated pain sites; the patients did not have access to the generic pain intensity score. Pearson's correlation coefficient was used to correlate the generic pain intensity score with site-specific pain intensity ratings, their mean and maximum, and the number of pain sites. RESULTS: The medians of the generic, maximum, and facial pain intensity scores were 49.5, 53, and 45.5, respectively. The generic pain intensity rating correlated more highly with the intensity scores reported for the most painful body site (r2 = 0.82; P < 0.001) than with the average rating across all painful sites (r2 = 0.62; P < 0.001), or the pain intensity score in the face (r2 = 0.61; P < 0.001). The number of pain sites did not correlate to any statistically significant degree with the generic pain intensity rating (r2 = 0.006; P = 0.65). CONCLUSION: The results of this study suggest that the maximum visual analog scale pain intensity score, observed in any body location, is a better reflection of the generic pain intensity rating than the corresponding score of the face. To avoid over-rating or underrating of facial pain intensity, patients should be instructed to provide site-specific pain intensity scores if painful comorbidity is present.
Explore the source record for details and available documents.
There is considerable evidence in support of differential information processing of the sensory-discriminative and motivational-affective meanings of pain. The purpose of this work was to examine whether temporal (acute, tonic, persistent) and spatial (local, regional, widespread) aspects of deep somatic pain influence the sensory and affective dimensions of pain. Acute pain consisted of a short bout of pain, lasting about 100 s. Tonic pain was the experience of experimentally maintained pain for 18 min. Both acute and tonic pain were induced by infusion of an algesic or control substance into muscle with the subject blinded with respect to the type of infusion and randomization of the application sequence. Comparing the response of experimental subjects to a group of matched cases with persistent masticatory myalgia alone or in combination with widespread musculoskeletal pain, we examine whether the experimental state is different from the matched clinical condition, and whether there is a difference between the condition being restricted to the face or not. The McGill pain questionnaire was used to assess the sensory and affective correlates of pain. The normalized sensory score for acute/unilateral face pain was different from that established for tonic/unilateral face pain (P = 0.055, borderline s.), and so was the normalized affective score (P = 0.009, s.). When comparing tonic/unilateral versus tonic/bilateral face pain, the affective scores increased with increased pain involvement (P = 0.009, s.) while the sensory sores were unaffected by the additional pain induced in the contralateral masseter muscle (P = 0.357, n.s). Notably, sensory and affective scores for tonic/bilateral and persistent/bilateral face pain were not statistically different (sensory: P = 0.169, n.s.; affective: P = 0.643, n.s). On the other hand, when contrasting persistent/bilateral face pain with persistent/ widespread musculoskeletal pain, both scores were significantly different (sensory: P < 0.001, s.; affective: P = 0.041, s.). Time in and spread of pain influenced the perceptual correlates of pain to a significant degree. The major increase in the sensory dimension occurred from 'no pain' to 'acute pain'. Affective scores showed the most significant increases from acute to tonic pain, particularly with greater spatial involvement. The significant increases in sensory scores observed when contrasting persistent facial pain alone and in combination with widespread musculoskeletal pain was attributed to the broader body experience. Because the perceptual correlates of tonic and matched persistent (chronic) pain states were similar, we concluded that it does not require months for the development of the sensory and affective meaning of persistent pain as assumed.
Many structural, behavioral, and pharmacological interventions imply that favorable treatment effects in musculoskeletal pain states are mediated through the correction of muscle function. The common theme of these interventions is captured in the popular idea that structural or psychological factors cause muscle hyperactivity, muscle overwork, muscle fatigue, and ultimately pain. Although symptoms and signs of motor dysfunction can sometimes be explained by changes in structure, there is strong evidence that they can also be caused by pain. This new understanding has resulted in a better appreciation of the pathogenesis of symptoms and signs of the musculoskeletal pain conditions, including the sequence of events that leads to the development of motor dysfunction. With the improved understanding of the relationship between pain and motor function, including the inappropriateness of many clinical assumptions, a new literature emerges that opens the door to exciting therapeutic opportunities. Novel treatments are expected to have a profound impact on the care of musculoskeletal pain and its effect on motor function in the not-too-distant future.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Two hundred consecutive female patients, who were referred to a university-based facial pain clinic, were asked to mark all painful sites on sketches showing the contours of a human body in the frontal and rear views. The drawings were analyzed with transparent templates containing 1875 (frontal view) and 1929 (rear view) square cells of equal size. The average patient scored 71.8 cells in the frontal and 99.7 cells in the rear view (corresponding to 3.8% and 5.2% of the maximum possible scores). In individual patient drawings, however, up to 42.7% and 44.9% of all cells were marked. Only 37 cases (18.5%) exhibited pain that was limited to the trigeminal system. An analysis of the pain distribution according to the arrangements of dermatomes revealed three distinct clusters of patients: (1) pain restricted to the region innervated by the trigeminal nerves (n = 37); (2) pain in the trigeminal dermatomes and any combination involving the spinal dermatomes C2, C3, and C4, but no other dermatomes (n = 32); and (3) pain sites involving dermatomes in addition to the ones listed above (n = 131). Mean ages in the three clusters were 38.7, 35.5, and 37.5 years, respectively (p = 0.62, n.s.). Widespread pain existed for longer durations (median, 48 months) than conditions involving local and regional pain (median, 24 months) (p = 0.02, s.). Our findings showed that among a great percentage of persistent facial pain patients the pain distribution is more widespread than commonly assumed, and that the persistence of pain in the regional and widespread pain presentations is significantly greater than in cases with pain limited to the trigeminal system.
OBJECTIVE: The assessment of facial mobility is a key element in the treatment of patients with facial motor deficits. In this study, we explored the utility of a three-dimensional tracking system in the measurement of facial movements. METHODS AND RESULTS: First, the three-dimensional movement of potentially stable facial soft-tissue, headcap, and dental landmarks was measured with respect to a fixed space frame. Based on the assumption that the dental landmarks are stable, their motion during a series of standardized facial animations was subtracted from that of the facial and headcap landmarks to estimate their movement within the face. This residual movement was used to determine which points are relatively stable (< or = 1.5 mm of movement) and which are not (> or = 1.5 mm of movement). Headcap landmarks were found to be suitable as references during smile, cheek puff, and lip purse animations, and during talking. In contrast, skin-based landmarks were unsuitable as references because of their considerable and highly variable movement during facial animation. Second, the facial movements of patients with obvious facial deformities were compared with those of matched controls to characterize the face validity of three-dimensional tracking. In all instances, pictures that appear to be characteristic of the various functional deficits emerged. CONCLUSIONS: Our results argue that tracking instrumentation is a potentially useful tool in the measurement of facial mobility.
Explore the source record for details and available documents.
Knowledge about the different kinds of treatment provided to patients with nonmalignant musculoskeletal facial pain is limited. The present study was based on 206 consecutive patients who were referred to a university-based tertiary care clinic for the diagnosis and management of persistent facial pain. Its purpose was to get information about the number and specialty of providers consulted by patients prior to their referral, and to follow the underlying treatment-seeking patterns. The results showed that on average 4.88 providers from 44 different categories were consulted. A general dentist or a dental specialist was seen by about 70% of patients. For patients whose first provider was a dentist, the most likely subsequent provider was another dentist. Conversely, if the first provider was a physician, chances were greater that the subsequent provider was a physician rather than a dentist. Among the nondental therapies patients received, physical therapy was chosen most frequently (42.2%). More than 60% of patients had at least one nondental treatment; however, the majority of these patients experienced two or more different types of such therapy (e.g., chiropractic, osteopathic, relaxation training). Patients' satisfaction with care and treatment was moderate, since only 18.5% of the patients were very satisfied, while 27.7% were dissatisfied or very dissatisfied. The present findings, which corroborate a recent study from the Kansas City, Missouri, region, indicate that patients with persistent facial pain see a large number of different providers, and that nonmedical/nondental treatment approaches are common. The moderate satisfaction experienced with any of the therapies points out that much needs to be done before this patient population is served satisfactorily.
STATEMENT OF PROBLEM: With diagnostic and therapeutic procedures being heavily influenced by the patient's chief complaint, the question arises whether this information alone represents a solid basis for clinical action. PURPOSE: The aim of this investigation was to assess the agreement between pain complaints and patient generated paper-and-pencil drawings of the distribution of pain in patients suffering from temporomandibular disorders. METHODS: The study included 140 adult female patients with temporomandibular disorders. Pain drawings served as a standard, against which the oral reports were compared. In 40 (29%) of the patients, pain was limited to the head and face; in the remaining subjects, it exceeded the boundaries of these regions. Nine potential pain sites were distinguished (head, face, neck, shoulders, arms, chest, abdomen, back, and legs). Whenever one of these regions was part of the drawing or the pain complaint, it was counted. Sensitivity, specificity, and kappa indices were computed for each site. RESULTS: Patients with pain limited to the head and face showed a close correspondence between pain report and drawing. On the other hand, patients with temporomandibular disorders with concomitant pain sites outside the head and face frequently did not mention these additional pain locations. This was reflected in low sensitivities (minimum: 0.00; maximum: 0.48) and low kappa values (minimum: -0.02; maximum: 0.19). CONCLUSIONS: This study showed that the chief complaint frequently underestimates the real extent of pain involvement.
Explore the source record for details and available documents.
Persistent pain is often accompanied by functional disability. This study investigated the effect of pain extent and the involvement of specific pain sites on pain-related disability, as determined by the Pain Disability Index (PDI). Complete data were available from 278 persistent facial pain (PFP) patients. Patients were divided into one of two groups based on drawings of their pain distribution. When the patient's pain drawing was limited to the region supplied by the trigeminal nerves (Nn. V(1) V(2), and/or V(3)), with or without the inclusion of any combination of the cervical dermatomes C2, C3 and C4, the patient was assigned to the local/regional pain group. If the pain extended beyond this area, the patient was allocated to the group exhibiting widespread pain. In addition to the PDI, patients filled out the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI). The local/regional pain group had significantly lower scores on the PDI, the BDI and STAI state than cases with widespread pain. Patients with widespread pain who indicated pain locations in any one or more of the extremities plus the lower back scored significantly higher on the PDI and the BDI than patients with no such combined involvement. Multiple regression analysis revealed that depressive preoccupation, pain extent and pain intensity were significant predictors of pain-related disability, whereas the STAI was not. If controlled for pain extent and pain intensity, the presence of high as opposed to low depressive scores added almost 11 points to the PDI score. These results showed that pain distribution, pain intensity and depressive mood are significant predictors of pain-related disability.