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Biomedical subjects

M N Janal

Publications and source records attributed to M N Janal.

16 recordsLinked to original sources
PubMed2003

Reliability of clinician judgements of bruxism.

Bruxism is considered to be a parafunctional disorder requiring treatment and is viewed as a risk factor for the development of temporomandibular disorders (TMDs). The purpose of this investigation is to examine the reliability of clinician judgements of bruxism severity. Twenty dentists who are faculty members in a dental school examined 29 stone casts and gold-plated models of individual teeth for evidence of bruxism. Ordinal ratings of bruxism severity for the 29 augmented models were made on two occasions, approximately 3 months apart. Inter-rater reliability among all clinicians, evaluated using intraclass correlation coefficients (ICCs), was poor at both time one and time two (i.e. ICC = 0.33 and 0.32, respectively), with somewhat better reliability found among those clinicians with above-average time elapsed since completion of dental training (i.e. ICC = 0.48 and 0.50 for time 1 and time 2, respectively). Three-month test-retest reliabilities were fair (ICC = 0.46) for the full group of raters and were unrelated to clinicians' degree of confidence in their ratings. These results indicate a need to standardize methods for clinical assessment of bruxism. Additionally, they have implications for studies using clinical assessments of bruxism to test the association between bruxism and other conditions such as TMDs.

Adult↗
PubMed2002

Materials design of ceramic-based layer structures for crowns.

Radial cracking has been identified as the primary mode of failure in all-ceramic crowns. This study investigates the hypothesis that critical loads for radial cracking in crown-like layers vary explicitly as the square of ceramic layer thickness. Experimental data from tests with spherical indenters on model flat laminates of selected dental ceramics bonded to clear polycarbonate bases (simulating crown/dentin structures) are presented. Damage initiation events are video-recorded in situ during applied loading, and critical loads are measured. The results demonstrate an increase in the resistance to radial cracking for zirconia relative to alumina and for alumina relative to porcelain. The study provides simple a priori predictions of failure in prospective ceramic/substrate bilayers and ranks ceramic materials for best clinical performance.

Aluminum Oxide↗
PubMed2001

How separate are the sensory, emotional, and motivational dimensions of pain? A multidimensional scaling analysis.

UNLABELLED: To map the structure of the space generated by verbal descriptors of pain, 41 male college students made pairwise similarity judgments to all possible pairings of 16 words that describe experiences commonly associated with noxious electrical stimulation. Individual Differences Scaling (INDSCAL) yielded four dimensions (D) in the group stimulus space: D-1, Intense to Moderate Experiences, contained two attributes: Strong Sensations and Strong Emotions; D-2, Moderate to Weak Experiences, exhibited two attributes: Moderate Sensations and Moderate Emotions; D-3, Motivational State, possessed two attributes: Pain and Arousal Level; D-4, Sensory Qualities, exhibited two attributes: Pain and Somatosensory Qualities. The interpretation of the dimensions was supported by Preference Mapping (PREFMAP) and by correlations between subject weights and (a) psychological tests and (b) responses to noxious electrical stimuli. CONCLUSION: semantically, the pain attribute or component of the total pain-suffering experience pervades emotional, motivational and somatosensory attributes. Pain is not an independent dimension. This means that a score on a pain rating scale is not a pure measure of the patient's pain, but is heavily influenced in unknown ways by the patient's emotional and motivational state.

Adolescent↗
PubMed2000

A placebo-controlled study of fluoxetine versus imipramine in the acute treatment of atypical depression.

OBJECTIVE: The atypical subtype of depression appears to be both well validated and common. Although monoamine oxidase inhibitors are effective in treating atypical depression, their side effects and prescription-associated dietary restrictions reduce their suitability as a first-line treatment. The objective of this study was to estimate the efficacy of the selective serotonin reuptake inhibitor (SSRI) fluoxetine in the treatment of major depression with atypical features. METHOD: One hundred fifty-four subjects with DSM-IV major depression who met the Columbia criteria for atypical depression were randomly assigned to receive fluoxetine, imipramine, or placebo for a 10-week clinical trial. Imipramine was included because its known efficacy for treatment of atypical depression helped to calibrate the appropriateness of the study group. RESULTS: In both intention-to-treat and completer groups, the effectiveness of both fluoxetine and imipramine was significantly better than that of placebo. The two medications did not differ from each other in effectiveness. Significantly more patients dropped out of treatment with imipramine than with fluoxetine. Before treatment, patients on average rated themselves as very impaired on psychological dimensions of general health and moderately impaired on physical dimensions, compared with population norms. The self-ratings of patients who responded to treatment essentially normalized on these measures. CONCLUSIONS: Despite earlier data that SSRIs might be the treatment of choice, fluoxetine appeared to be no better than imipramine in the treatment of atypical depression, although fluoxetine was better tolerated than imipramine.

Adolescent↗
PubMed1997

Central poststroke pain and Wallenberg's lateral medullary infarction: frequency, character, and determinants in 63 patients.

UNLABELLED: Central poststroke pain (CPSP) is an infrequently recognized complication of lateral medullary infarction (LMI). We determined the frequency, nature, and predictors of this complication in 63 patients with LMI. The hypothesis tested was that the degree of clinical sensory loss and extent of infarction seen on MRI, both graded by a predetermined scoring scale, would be predictive of CPSP. We also performed quantitative sensory testing (QST) of thermal and pressure sensation thresholds in a subgroup of 19 patients (nine with CPSP and 10 without) to analyze in detail the spinothalamic and trigeminothalamic systems mediating these modalities from both sides of the face and body. We analyzed these results for specific markers of CPSP. RESULTS: CPSP developed in 25% (16/63) of the patients, all within 6 months. This was constant and severe with frequent allodynia, but responded in all cases to amitriptyline and recurred promptly on attempted weaning. CPSP affected the ipsilateral peri-orbital region most commonly, either alone or in combination with the contralateral limbs. Ipsilateral neurotrophic facial ulceration developed in two cases. CPSP correlated significantly (Fisher's exact test, p < 0.0002) with the degree of clinical sensory loss but not with the size of infarction seen on MRI (Fisher's exact test, p = 0.7). QST revealed a highly specific (100%) and sensitive (89%) finding for CPSP-thresholds from the check contralateral to the LMI were normal in eight of nine cases with CPSP and abnormal in all of the 10 cases without CPSP. Abnormalities in the face contralateral to the infarct are referable to the crossed trigeminothalamic tract in the medullary reticular formation medial to the infarcted lateral medulla. We conclude that this argues for the theory that central pain is caused by denervation sensitivity of the "paleo"-reticulothalamic connections due to a selective "neo"-spinothalamic lesion.

Adult↗
PubMed1996

Effects of cognitive coping skills training on coping strategies and experimental pain sensitivity in African American adults with sickle cell disease.

The present study examined whether training in cognitive coping skills would enhance pain coping strategies and alter pain perception in adults with sickle cell disease (SCD). Sixty-four African Americans with SCD were randomly assigned to either a cognitive coping skills condition (three 45-min sessions in which patients were trained to use 6 cognitive coping strategies) or a disease-education control condition (three 45-min didactic-discussion sessions about SCD). Pain sensitivity to calibrated noxious stimulation was measured at pre- and posttesting, as were cognitive coping strategies, clinical pain, and health behaviors. Results indicated that, compared with the randomly assigned control condition, brief training in cognitive coping skills resulted in increased coping attempts, decreased negative thinking, and lower tendency to report pain during laboratory-induced noxious stimulation.

Adaptation, Psychological↗
PubMed1994

On the absence of correlation between responses to noxious heat, cold, electrical and ischemic stimulation.

Is a person's response to one noxious stimulus similar to his/her responses to other noxious stimuli? This long-investigated topic in pain research has provided inconclusive results. In the present study, 2 samples were studied: one using 60 healthy volunteers and the other using 29 patients with coronary artery disease. Results showed near-zero correlations between measures of heat, cold, ischemic, and electrical laboratory pains, as well as between these laboratory pains and an idiopathic pain, the latency to exercise-induced angina in the patients. Power analyses showed that the sample sizes were sufficient to detect a correlation of 0.50 or greater at the 0.05 level 99% of the time in the healthy volunteers, and between 80 and 85% of the time in the patients. Reliability analyses indicated retest correlations on the order of 0.60 for these measures, indicating that the lack of correlation between modalities was not due to unreliability within a measure. These studies fail to demonstrate alternate-forms reliability among these tests, and also fail to support the notion that a person can be characterized as generally stoical or generally complaining to any painful stimulus. In practice, this implies that a battery of tests should generally be used to assess pain sensitivity and also that assessments of one pain modality are not generally useful for making inferences about another.

Adult↗
PubMed1993

Multidimensional scaling of painful electrocutaneous stimulation: INDSCAL dimensions, signal detection theory indices, and the McGill Pain Questionnaire.

Individual-differences multidimensional scaling (INDSCAL) determined the dimensions underlying ratings of electrocutaneous stimuli, which ranged from innocuous levels to individual pain intolerance at each of three frequencies. Twenty-five healthy males made pairwise similarity judgments of these 15 stimuli for the INDSCAL procedure, and then rated each stimulus on nine property scales. Signal detection theory indices, as well as ratings on the McGill Pain Questionnaire (MPQ), were also obtained. A Sensory Magnitude dimension scaled the stimuli from lowest to highest perceived intensity; this dimension was related to sensory, affective, and arousal property scales. A Frequency dimension ordered the stimuli from lowest to highest frequency; this dimension was related to the Fast-Slow property. Compared to the Frequency dimension, the Sensory Magnitude dimension was more salient to subjects who better discriminated among painful stimulus intensities, set a more stoical pain report criterion, and were less apt to endorse frequency-related MPQ descriptors. Thus, variation of physical intensity and frequency elicited complementary dimensions of subjective judgment, which were related to perceptual and attitudinal differences among individuals.

Adolescent↗
PubMed1991

Sensory decision theory and visual analogue scale indices predict status of chronic pain patients six months later.

Thirty-nine outpatients suffering from chronic pain were studied in a multidisciplinary program. Pain intensity on a visual analogue pain scale (VAPS), sensory decision indices of thermal discriminability, P(A), and pain report criterion, B, age and sex obtained before treatment, were used to predict the patients' status, determined by a follow-up questionnaire 6 mo later. The results showed that patients who were high on the VAPS at intake had shorter pain relief and decreased physical activities on follow-up. Patients with better thermal discriminability had greater pain relief, while those with low pain report criterion, that is, less stoical, demonstrated improved physical activity, and more social and hobby activities. Patients who were less stoical to thermal stimuli (lower pain criterion) took fewer centrally active drugs after treatment. Younger patients showed greater improvement at follow-up. The data indicate that the VAPS, thermal discriminability, and pain report criterion all predict the duration of pain relief after treatment. Nevertheless, each of these variables had its individual character. The VAPS was most efficient in predicting physical activities, thermal discriminability related best to pain relief, and pain report criterion to social and hobby activities as well as drug intake.

Adult↗
PubMed1991

Multidimensional scaling of painful and innocuous electrocutaneous stimuli: reliability and individual differences.

Multidimensional scaling was used to explore whether a single intensity dimension underlies the perception of both nonpainful and painful electrical stimuli, or whether separate dimensions are required. For the scaling (INDSCAL) procedure, 41 healthy volunteers judged the similarity between all pairs of 16 intensities, which ranged from imperceptible levels to pain tolerance. For the property mapping (PREFMAP) analysis, they rated each intensity on each of 16 property scales. INDSCAL revealed four dimensions that showed high levels of both test-retest and split-half reliability. The first dimension scaled stimuli from the lowest intensity to the pain threshold. This dimension was related to property scales of sensation, affect, and arousal, but not pain, suggesting a sensory magnitude dimension. The second dimension ordered the stimuli from mildly to severely painful and was related to the painful property scale, suggesting a pain intensity dimension. Third and fourth dimensions, which refined the scaling of nonpainful stimuli, were also found. Variability in the subjects' use of the painful and nonpainful dimensions was related to their choice of stimulus descriptors. Like clinical pain, laboratory pain requires multidimensional assessment.

Adolescent↗
PubMed1990

Multidimensional scaling of subjective judgements of drug similarities among ketocyclazocine, morphine, cyclazocine, naloxone and placebo.

Profiles of the subjective and physiologic effects of opioid drugs in man cannot be assigned with precision to specific opioid drug-receptor interactions. We administered a set of training doses of ketocyclazocine, morphine, cyclazocine, naloxone and placebo to 10 drug-using volunteers and obtained similarity judgements between each of 2 test doses of the drugs and a training dose. These data were submitted to multidimensional scaling analysis (INDSCAL) using both neighboring cells estimates and root mean square estimates to estimate missing cells in the data matrices. The results of these analyses are convergent, appear valid and indicate that there are three drug dimensions expressed in this data set: morphine versus placebo and naloxone; cyclazocine and ketocyclazocine versus placebo and naloxone; and ketocyclazocine versus cyclazocine. We interpret this result as supporting evidence that in the set of five drugs studied, three subjective states are induced.

Adult↗
PubMed1986

Multidimensional scaling reveals two dimensions of thermal pain.

The Individual Differences Scaling (INDSCAL) model of multidimensional scaling was used to explore the dimensions of thermal pain. The observers made 66 similarity judgments to all pairs of 12 different thermal stimulus intensities ranging from zero to noxious. Analysis of the data revealed a two-dimensional group stimulus space. The major dimension ordered the stimuli with respect to their intensity. This quantitative, strength-of-sensation dimension may be interpreted as indicating how weak or strong a stimulus feels, apart from any secondary qualities of warmth or pain. The second dimension was related to the qualitative aspects of the stimuli. This bipolar dimension contained two attributes: a pain attribute ranging from just detectable warmth to painful, and a warm-hot attribute running from just detectable warmth to hot. This study demonstrates the utility of the INDSCAL approach to the understanding of pain and offers a new technique for answering the age-old question concerning the number and qualities of the dimensions underlying the pain experience.

Adult↗
PubMed1986

Altered pain and visual sensitivity in humans: the effects of acute and chronic stress.

In the runner study, as measured by tourniquet ischemic pain, exercise stress produced hypoalgesia 20 minutes post-run, followed by hyperalgesia and euphoria at 30 minutes. The hypoalgesia and euphoria were reversed by naloxone. Exercise stress also produced a decrease in P(A), suggesting hypoalgesia to the thermal cutaneous stimulation. However, this analgesia was not naloxone reversible. Nor did exercise stress produce analgesia to cold-pressor pain. In the acupuncture study, noxious electrical stimulation of classical acupuncture sites failed to produce analgesia either during or after stimulation. However, expectation did produce a change in the pain report criterion, but only in the acupunctured arm. Noxious electrical stimulation (TENS) of the median nerve produced no analgesia outside of the related segmental area, that is, acute electrical pain did not produce generalized hypoalgesia. Thus, the effects of the stress produced by noxious electrical stimulation differ from that produced by exercise. In contrast to the results of the acute pain studies, chronic clinical pain, which combines mental stress and pain stress, produced strong hypoalgesia and anesthesia. Again, in contrast to the acute experimental pain studies, the emotional stress of mental illness produces hypoalgesia, but not anesthesia. Finally, the somatosensory system is not the only the sensory system affected by stress. Cold-pressor pain decreases visual sensitivity both during and for a few minutes following stimulation, and does not interfere with short-term (supra-digit span) memory.

Acupuncture Therapy↗
PubMed1982

A model of clinical pain. Technique for evaluation of analgesic agents.

A method is described utilizing repetitive electrical stimulation for the production of long-term continuous pain which approaches the quality of clinical pain. This technique provides for on-line monitoring of actual power delivered to the subject. Incremental stimuli of high and low intensities were randomly superimposed on continuous painful background electrical stimulation. Subjects were studied in a triple crossover design with acupuncture, codeine and baseline treatments. Data were evaluated by Sensory Decision Theory (SDT) procedures. The codeine compound significantly raised the response criterion to higher intensity stimuli but did not effect perception of low intensity stimuli, indicating an analgesic but not an anesthetic effect. No significant differences were found between control and acupuncture results for either pain discriminability or pain report criterion. The results are discussed with regard to the physiological effects of electrical stimulation and the merits of this new stimulation technique.

Acupuncture Therapy↗
PubMedDate not supplied

Effects of moderate and high doses of marihuana on thermal pain: a sensory decision theory analysis.

Sixteen habitual marihuana users, selected for their good mental and physical health, were hospitalized for three months in the New York State Psychiatric Institute. During the first month, the subjects were drug free; during the second month, they smoked marihuana cigarettes provided by NIDA (2% THC, 20 mg per cigarette) at the rate of 3 to 12 a day. A modified Hardy-Wolff dolorimeter was used to present 20 thermal stimuli of 30-second duration in a random manner at nine different intensities. Subjects responded from a 14-category scale, and data were analyzed according to sensory decision theory analysis. During the third month, the subjects were again drug free. At the noxious thermal intensities, there was a decrease in the pain report criterion during the first two weeks of smoking. The pain enhancement effect was followed by return to the presmoking pain level during weeks 3 and 4 and in the postsmoking period, indicating that tolerance had developed. There was also an increase in pain discriminability during the four weeks of smoking which extended for one week after smoking. Tolerance developed to the pain report criterion but not to the thermal discriminability. This study suggests that marihuana may have hyperalgesic activity and probably enhances the perception of pain, in moderate smokers. In contrast, heavy smoking had little effect on discriminability and caused an increase in the pain report criterion.

Adolescent↗