Memory for pain and affect in chronic pain patients

Radioligand binding studies were performed to determine the effect of various cations on the characteristics of [3H]glibenclamide binding to its high-affinity receptor in rat cerebral cortex membranes. Mg2+ was shown specifically to reduce radioligand binding to membranes pretreated with 5 mM EDTA. CaCl2 enhanced [3H]glibenclamide binding whilst MnCl2, KCl and NaCl were without significant effect. 2 mM MgCl2 induced a statistically significant rightward shift in the dissociation constant for glibenclamide obtained from both saturation and competition studies. These results suggest that Mg2+ may participate in the regulation of the sulphonylurea receptor in the rat cerebral cortex.     

Attention and verbal learning in patients with chronic fatigue syndrome

Former neuropsychological studies with Chronic Fatigue Syndrome (CFS) patients evaluated a broad range of cognitive functions. Several, but not all, reported subtle attentional and memory impairments suggesting possible mild cerebral involvement. In this study, a battery of attentional tests and a verbal memory task were administered to 20 CFS patients and 22 healthy controls (HC) in order to clarify the specific nature of attention and memory impairment in these patients. The results provide evidence for attentional dysfunction in patients with CFS as compared to HC. CFS patients performed more poorly on a span test measuring attentional capacity and working memory. Speeded attentional tasks with a more complex element of memory scanning and divided attention seem to be a sensitive measure of reduced attentional capacity in these patients. Focused attention, defined as the ability to attend to a single stimulus while ignoring irrelevant stimuli, appears not to be impaired. CFS patients were poorer on recall of verbal information across learning trials, and poor performance on delayed recall may be due to poor initial learning and not only to a retrieval failure.     

Interpersonal stress and pain behaviors in patients with chronic pain.

Evaluated the role of interpersonal stress in eliciting pain behavior. 34 male patients with chronic back pain and their wives participated in a randomized between-groups study examining the effects of 2 interactional conditions (i.e., maritally focused stress interview and neutral talking control task) on subsequent persistence in a physically demanding task and with self-reports of pain. Results show that a greater proportion of patients in the stress interview group terminated the physical activity task prematurely, compared with controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expectancy variables predicting tolerance and avoidance of pain in chronic pain patients

Contemporary views on etiology and treatment for solitary bone cyst are presented. Coehn theory of metaphyseal blood flow disturbances as the cause of solitary cyst formation has been emphasized. Minimally invasive treatment modalities have been honored as steroid or autogenous marrow injections into the cyst. Campannaci classification, the most versatile one, embracing various types of cyst remodeling after treatment has been introduced in Polish literature for the first time.     

Clinical correlates of insomnia in patients with chronic illness

BACKGROUND: Patients with chronic insomnia are more likely to develop affective disorders, cardiac morbidity, and other adverse health outcomes, yet many clinicians tend to trivialize the complaint of insomnia or to attribute it only to psychiatric causes. OBJECTIVES: To estimate the prevalence and longitudinal course of insomnia in patients with documented chronic medical illness and/or depression and to quantify the associations between specific chronic conditions and insomnia. METHODS: The presence of mild or severe insomnia was based on responses to a sleep questionnaire completed by 3445 patients with at least 1 of 5 physician-identified chronic conditions (hypertension, diabetes, congestive heart failure, myocardial infarction, or depression) at baseline; a subsample of 1814 patients completed follow-up questionnaires at 2 years. Using multivariate techniques, we evaluated the relationship between chronic conditions, patient-reported comorbidities, and insomnia (complaints of initiating and maintaining sleep), adjusting for sociodemographics and health habits. RESULTS: Sixteen percent of study patients had severe and 34% had mild insomnia at baseline. At 2-year follow-up, 59% (95% confidence interval, 55%-63%) of patients with mild insomnia and 83% (95% confidence interval, 78%-88%) of patients with severe insomnia at baseline still had sleep problems. Odds ratios corresponding to mild and severe insomnia for key risk factors were as follows: current depressive disorder, 2.6 and 8.2; subthreshold depression, 2.2 and 3.4; congestive heart failure, 1.6 and 2.5; obstructive airway disease, 1.6 and 1.5; back problems, 1.4 and 1.5; hip impairment, 2.2 and 2.7; and prostate problems, 1.6 and 1.4. The majority of insomnia-comorbidity associations observed at baseline persisted at 2-year follow-up. CONCLUSIONS: Patients with insomnia require follow-up, as the majority continue to be bothered by difficulty initiating and maintaining sleep. In addition to detecting affective disorders in patients with insomnia, clinicians should focus on medical conditions that disturb sleep, especially cardiopulmonary disease, painful musculoskeletal conditions, and prostate problems.     

Mechanical and thermal allodynia in chronic central pain following spinal cord injury

The interstitial cells of Cajal (ICC) are found in a number of different locations in the gastrointestinal tract, where they form close associations with both muscle cells and nerve terminals. In this study we examined the embryological origin of ICC in the mouse intestine to determine whether they arise from the neural crest or from the intestinal wall. Segments of intestine were removed from embryonic mice either before or after the arrival of neural crest cells (the precursors of enteric neurons and glial cells) and transplanted under the renal capsule of host (adult) mice and allowed to develop for 18-41 days. In the mouse intestine, antibodies to c-kit protein selectively label ICC at a variety of locations, and antibodies to the NK1 receptor (the receptor for substance P) labels ICC at the level of the deep muscular plexus in the small intestine and a subpopulation of enteric neurons in the large intestine. The presence of neurons in the explants was examined using antisera to neuron-specific enolase, substance P, and calretinin. In segments of small and large intestine explanted after the arrival of neural crest cells, immunoreactive neurons and c-kit- and NK1-immunoreactive ICC were present with a distribution similar to that seen in control tissue at a similar developmental age. In segments of large intestine explanted before the arrival of neural crest cells, neurons were not present; however, c-kit-immunoreactive ICC were present in these aneuronal explants, indicating that ICC do not arise from the neural crest. The source of ICC in mammals is therefore likely to be the mesenchyme of the gut.     

Stimulation of the central and peripheral nervous system for the control of pain

After suffering some setbacks since its introduction in 1967, stimulation of the spinal and peripheral nervous systems has undergone rapid development in the last ten years. Based on principles enunciated in the Gate Control Hypothesis that was published in 1968, stimulation-produced analgesia [SPA] has been subjected to intensive laboratory and clinical investigation. Historically, most new clinical ideas in medicine have tended to follow a three-tiered course. Initial enthusiasm gives way to a reappraisal of the treatment or modality as side-effects or unanticipated problems arise. The last and third phase proceeds at a more measured pace as the treatment is refined by experience. This review is divided into three parts as it traces the progress of spinal cord stimulation [SCS] and peripheral nerve stimulation [PNS]. The review commences with a discussion of the theory of SCS and PNS, and is followed by early reports during which it became apparent that the modality is essentially only effective in the treatment of neuropathic pain. The last section describes the modern experience including efficacy in specific types of pain and concludes with recent accomplishments that dramatize the relief of pain which can be achieved in nonoperable peripheral vascular disease or myocardial ischemia. Over the years, a search for those transmitters that might be influenced by spinal cord stimulation focused on somatostatin, cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), neurotensin and other amines, although only substance "P" was implicated. More recently, in animal studies, evidence that GABA-ergic systems are affected may explain the frequent successful suppression of allodynia that follows spinal cord stimulation. During the past eight years, much attention has been directed to studies that use a chronic neuropathic pain model. While PNS held significant promise as a pain relieving modality, early electrode systems and their surgical implantation yielded variable results due to evolving technical and surgical skills. These results dramatically reduced the continued development of PNS, which then gave way to a preoccupation with SCS. Modern development of SCS with outcome studies, particularly in relation to failed back surgery syndrome [FBSS] and the outcome of peripheral nerve surgery for chronic regional pain syndromes, has earned both modalities a place in the ongoing management of patients with intractable neuropathic pain. The last section, dealing with pain of peripheral vascular and myocardial ischemia, is perhaps one of the more exciting developments in stimulation produced analgesia and as the papers discussed demonstrate, can provide a level of analgesia and efficacy that is unattainable by other treatment modalities. SCS and PNS has an important role to play in the management of conditions that are otherwise refractory to conservative or other conventional management.     

Physician judgments of chronic pain patients

Recent evidence has indicated that physician judgments of patients can be influenced by contextual factors. This study examined three contextual factors relevant to hypothetical patients with low back pain, using vignettes that were varied in a 2 x 2 x 2 factorial design: level of reported pain (high vs low), level of supporting medical evidence (high vs low), and the valence of the physician-patient interaction (positive vs negative). Perceived levels of pain, disability, emotional distress, and somatic preoccupation were rated by internists after reading a vignette. Ratings of pain and disability were lower for patients without supporting medical evidence; ratings of distress, somatic preoccupation, and disability were greater for patients who exhibited negative rather than positive affect; internist ratings of pain were lower than patient ratings among patients reporting high levels of pain, while ratings were inflated for patients with low levels of pain. The results suggest that characteristics of both the patient and the situation may influence medical judgments.     

Assimilation: central and peripheral effects

Assimilation and contrast have opposite effects: Contrast leads to an increase of perceived differences between neighbouring fields, whereas assimilation leads to a reduction. It is relatively easy to demonstrate these effects, but the precise localisation of these effects in the perceptual system is not yet possible. In an experiment the strength of assimilation effects was modified by adding spatial noise. By varying the localisation in perceived space of the added noise (by presentation of the noise pattern with different binocular disparities) the masking effect of this noise can be influenced. Masking caused by binocularly disparate noise is less than masking caused by binocularly non-disparate noise. It is concluded that the effect at least partly occurs beyond the (binocular) locus of separation in different depth planes. A similar approach, involving moving noise, is also presented. Finally, several demonstrations show that images that are peripherally similar can give rise to differences in the perceived amount of assimilation. These effects further indicate that a central mechanism is involved in assimilation.     

Increasing the reliability and validity of pain intensity measurement in chronic pain patients

This study examined the effects of increasing the number of assessments on the reliability and validity of measures of average pain intensity. Two hundred chronic pain patients completed 2 weeks of hourly pain ratings. A series of regression analyses were performed, and test-retest stability, internal consistency and validity coefficients were computed to address 4 questions. (1) Are chronic pain patients' reports of pain similar from one day to another? (2) What is the reliability and validity of a single rating of pain intensity when used as an indicant of average pain? (3) How many assessments (data points) are required to obtain estimates of average pain intensity with adequate to excellent psychometric properties? (4) How important is it to sample pain from different days? The results were consistent with predictions based on patients' self-reports of their pain and on psychometric theory. First, the majority of patients did not report similar levels of pain from one day to another, and average pain scores calculated from ratings obtained from a single day were less stable than those calculated from ratings obtained from multiple days. Also, and as expected, the results indicate that a single rating of pain intensity is not adequately reliable or valid as a measure of average pain. However, a composite pain intensity score calculated from an average of 12 ratings across 4 days demonstrated adequate reliability and excellent validity as a measure of the average pain in this sample of chronic pain patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Active and passive coping strategies in chronic pain patients

This study assessed the validity of active and passive coping dimensions in chronic pain patients (n = 76) using the Coping Strategies Questionnaire and the Vanderbilt Pain Management Inventory. The validity of active and passive coping dimensions was supported; passive coping was strongly related to general psychological distress and depression, and active coping was associated with activity level and was inversely related to psychological distress. In addition, the Coping Strategies Questionnaire was found to be a more psychometrically sound measure of active and passive coping than the Vanderbilt Pain Management Inventory.     

Self-reported sleep and mood disturbance in chronic pain patients

BACKGROUND: Gastrostomies provide reliable long-term enteral access in patients with traumatic brain injuries. The impact of technique of gastrostomy on total hospital cost is not known. METHODS: A retrospective analysis of patients who sustained head trauma and required gastrostomies for long-term enteral access between 1 July 1990 and 1 July 1996 was performed. RESULTS: The patients who received percutaneous endoscopic gastrostomies (PEG) were similar to patients who received Stamm gastrostomies (OPEN) with respect to age, injury severity score, mechanism of injury, associated injuries, complication rates, and deaths. Total hospital costs ($ x 10(3)) were lower for patients who had PEGs placed in the intensive care unit (78.2 +/- 37.4) or endoscopy suite (71.9 +/- 37.7) compared with PEGs placed in the operating room (122.4 +/- 75.7) or OPEN gastrostomies (119.8 +/- 65.1). CONCLUSIONS: In head-injured patients, PEGs are a reliable method of obtaining long-term enteral access with a complication rate equivalent to Stamm gastrostomies. If performed in either the intensive care unit or the endoscopy suite, PEGs are associated with significantly reduced total hospital costs.     

Management of chronic pain among elderly patients

OBJECTIVE: To identify the Staphylococcus aureus capsular serotypes that are not typable, using capsular serotypes 5 and 8, which are currently used to type S aureus isolated from cows with mastitis. SAMPLE POPULATION: Milk samples (n = 273) from cows with mastitis in 178 dairy herds in California, Wisconsin, Michigan, Texas, and New York that were collected by state diagnostic laboratories and S aureus-positive milk samples collected by Veterinary Health Services in the United Kingdom (15), France (22), The Netherlands (36), and Germany (21). PROCEDURE: Capsular serotyping of coded isolates was performed by use of direct cell agglutination and immunoprecipitation of cell extracts with antisera specific for capsular types 5 and 8 and a newly developed S aureus serotyping antiserum 336. RESULTS: In the United States, S aureus capsular types 5 and 8 accounted for 18 and 23% of the isolates, respectively, and type 336 accounted for 59%. Percentage of capsular serotypes in European samples were as follows: type 5 = 34%, type 8 = 34%, type 336 = 30%, and nontypable = 2%. CONCLUSIONS: Serotypes 5 and 8 accounted for only 41% of S aureus isolates from US milk samples, but accounted for 70% of isolates from European milk samples. Addition of the newly developed serotyping antiserum 336 to the typing scheme accounted for 100% of US samples and 98% of European samples and will enable development of a more comprehensive S aureus vaccine.     

Effects of gabapentin on the different components of peripheral and central neuropathic pain syndromes: a pilot study

Anticonvulsants are widely used in the treatment of neuropathic pain, and are assumed to act preferentially on lancinating, shooting pain. In the present study, the effects of gabapentin, a novel anticonvulsant, were evaluated systematically on both spontaneous and evoked pain in 18 patients with peripheral nerve injuries or central lesions. Gabapentin was administered orally in gradually increasing doses up to a maximum of 2,400 mg/day. Evaluations of spontaneous ongoing and paroxysmal pain, allodynia and hyperalgesia were performed at the beginning of the study ('baseline') and 6 weeks after the steady-state dose had been reached. Quantitative sensory tests were used to measure detection and pain thresholds to mechanical and thermal stimuli and the responses to suprathreshold stimuli. Gabapentin induced a moderate and statistically significant relief of ongoing spontaneous pain and was particularly effective in reducing paroxysmal pain. A striking finding was the significant effect on brush-induced and cold allodynia. In contrast, no effects were observed on detection and pain thresholds to static mechanical and hot stimuli. Side effects were generally minor and did not interfere with everyday activities. The present study suggests that gabapentin has preferential antihyperalgesic and/or antiallodynic effects, and is equally effective in pain due to peripheral nerve injuries and central lesions.     

Relation between catastrophizing and depression in chronic pain patients.

The relation between catastrophizing, depression, and pain was examined in 125 chronic pain patients. The Coping Strategies Questionnaire (CSQ) developed by A. K. Rosenstiel and F. J. Keefe (see record 1984-18170-001) assessed patients' use of cognitive and behavioral strategies to cope with chronic pain. A significant association between catastrophizing and depression was found. In order to address questions of measurement redundancy, 6 clinical psychologists rated the degree to which items on the CSQ reflected depressive symptomatology. All items contained in the Catastrophizing subscale were rated by all psychologists as being reflective of symptoms of depression and were removed from the CSQ. When this subscale was excluded, none of the remaining CSQ subscales were significantly related to depression. The discussion addresses the interpretive difficulties that arise from hypothesizing mediating relations between variables that are conceptually and operationally confounded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polymedication and medication compliance in patients with chronic non-malignant pain

Most reports of polymedication among patients with chronic non-malignant pain have relied only on the patient's statements which have been proven to be unreliable regarding actual drug consumption. This study investigates the incidence of polymedication and medication compliance in these patients by applying objective methods. One-hundred-nine consecutive patients predominantly with facial, neuropathic or back pain were interviewed about present medication at first admission to the pain clinic. Reports were verified by toxicological urine screening, mainly with thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) coupling. Follow-up investigations of 61 patients were conducted within 1 and 24 months after beginning therapy. Polymedication--here defined as daily intake of 3 or more preparations--was found in 41 patients (38%) in the initial investigation. In only 74 patients (68%) did the results of urine screening correspond with their reports: 23 patients (21%) concealed the consumption of drugs, and 2 patients (2%) did not take their medications. Ten cases were not interpretable. Fifty-four percent of the drugs concealed were psychotropic substances, mostly benzodiazepines, and 42% were analgesic combinations, partly with psychotropic additives. Drug intake was concealed significantly more often with polypharmacy which was occurring more frequently in patients with headache or facial pain, longer duration of pain, young age, psychiatric diagnosis and history of substance abuse. Patients with initial non-compliance were more likely to conceal drug consumption in follow-up investigations as well (P = 0.05). Therefore, screening for medication compliance in patients with chronic non-malignant pain is recommended, especially in those with the abovementioned risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pain-related correlates of MMPI profile subgroups among back pain patients.

96 17–80 yr old male and 218 16–83 yr old female outpatients at a back pain clinic were administered the Cornell Medical Index, the Minnesota Multiphasic Personality Inventory (MMPI), the McGill Pain Assessment Questionnaire—Revised, and the Shipley Institute of Living Scale. Analysis showed greater disruption of daily activities and affective disturbance and poorer adjustment to pain among subgroups with elevated neurotic scales. Results are consistent with those of similar studies of chronic pain patients showing that MMPI profile subgroups may be identified that are associated with relatively unique pain-related correlates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural brain correlates of verbal and nonverbal fluency measures in Alzheimer's disease.

This study examined the relationships between regional brain volumes and semantic, phonological, and nonverbal fluency in 32 participants with Alzheimer's disease (AD). Object but not animal semantic fluency correlated with frontal and temporal gray matter volumes. Phonological fluency was not significantly associated with any brain volume examined. Nonverbal fluency was selectively associated with bilateral frontal gray matter volumes. Hippocampal volumes, although markedly reduced in these patients, were not related to any of the fluency measures. Results lend evidence to the importance of the frontal lobes in the directed generation of nonverbal and verbal exemplars by AD patients. Furthermore, both left and right-hemisphere regions contribute to the generation of verbal and nonverbal exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved)