Biomedical subjects

J P Hatch

Publications and source records attributed to J P Hatch.

At least 37 records · Page 2Linked to original sources

PubMed1999

Histories of childhood trauma and the effects on risky HIV behaviors in a sample of women drug users.

A cross-sectional study was conducted to examine the association between childhood trauma and current human immunodeficiency virus (HIV) risk behaviors of 181 active illicit-drug-using women in San Antonio, Texas. We found very few statistically significant associations, which could he explained by (a) childhood trauma subtypes not being mutually exclusive, (b) clustering of mild-to-severe forms of abuse. and (c) childhood trauma having an indirect, rather than direct, effect on HIV risk behavior. Public health implications from this study are that prevention programs need to consider past and current individual and environmental factors that influence HIV sexual risk behaviors in women drug users.

Adolescent↗

PubMed1999

Psychosocial predictors of high-risk patients undergoing orthognathic surgery.

The purpose of this analysis was to identify a set of predictor variables that are prospectively related to postsurgical outcomes. Specifically, psychosocial characteristics were sought to predict postsurgical outcomes. The 5 Revised Symptom Checklist-90 (SCL-90-R) scales, the neuroticism score of the Eysenck Personality Inventory (EPI), the psychosocial domain score from the Sickness Impact Profile (SIP), and 4 scales from the Oral Health Status Questionnaire (OHSQ) were used as the predictors. A total of 31 male and 86 female subjects participated in this multicenter randomized trial, which compared rigid and wire fixation. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, and 2 years after surgery. Baseline oral health was used as an indicator of postsurgical oral health functioning. A path analytic model of influences on presurgical oral health was estimated (R2 = 0.43). The results suggest that presurgical screening of demographic characteristics (age, sex, and ethnicity), oral health (the OHSQ), quality of life issues (SIP), and personality features (SCL-90-R), accounts for 23% to 39% of the variance in postsurgical oral health outcomes. The path analysis conducted suggests that a patient's age, ethnicity, gender, and elevated scores on the EPI have indirect effects on postsurgical health. As determined by a 2-stage least squares regression model, 3 variables--the patient's presurgical oral health (per the OHSQ), pre- and postsurgical Global Severity Index (GSI) score from the SCL-90-R, and the psychosocial scale score from the SIP--were found to have a statistically significant impact on postsurgical outcomes. Additionally, the GSI, SIP, and OHSQ are reliable measures in predicting oral health outcomes.

Adult↗

PubMed1998

Health-related quality of life following orthognathic surgery.

A randomized controlled trial was conducted to compare the effects of rigid and wire fixation on health-related quality of life following surgical mandibular advancement in patients with Class II malocclusions. Sixty-four patients randomly selected to receive rigid fixation with bicortical position screws were compared with 63 patients randomly selected to receive nonrigid fixation with inferior border wires. Quality of life was measured using the Sickness Impact Profile, a generic measure of health-related quality of life, and the Oral Health Status Questionnaire, a specific measure of oral health and function designed for use with orthognathic surgery patients. Patients were evaluated prior to application of orthodontic appliances, approximately 2 weeks before surgery, and 1 week, 8 weeks, 6 months, 1 year, and 2 years following surgery. Neither instrument revealed a statistically significant difference in quality of life between wire and rigid fixation at any time period. The health-related disability associated with Class II malocclusion is modest compared to many other medical conditions. Nonetheless, orthognathic surgery patients exhibit progressive and statistically significant improvement in health-related quality of life across a wide variety of functional domains, regardless of the fixation method used.

Adolescent↗

PubMed1998

Effects of major Class II occlusal corrections on temporomandibular signs and symptoms.

This study explored the relationship between malocclusion and signs and symptoms of temporomandibular disorders (TMD) in 124 patients with severe Class II malocclusion, before and 2 years after bilateral sagittal split osteotomy (BSSO). Patients were evaluated with the Craniomandibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to assess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index scores dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 years postsurgery (P < 0.001). The CMI and masticatory index (MI) for muscle pain indicated clinically small but statistically significant improvement (P = 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0.15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 33 (26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnitude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.

Adolescent↗

PubMed1997

Comparing prospective and retrospective evaluations of temporomandibular disorders after orthognathic surgery.

The authors conducted a study to document agreement between prospective examinations performed by trained clinical trial examiners and retrospective surgical chart reviews in identifying signs and symptoms of temporomandibular disorders, or TMD. Only a small fraction of the signs and symptoms identified by clinical trial examiners were documented in the surgical charts. Studies relying on retrospective chart reviews may seriously underestimate signs and symptoms of TMD.

Adolescent↗

PubMed1996

Using statistical equivalence testing in clinical biofeedback research.

The technique of statistical equivalence testing is described and recommended for use in clinical biofeedback research. Equivalence testing is valuable in aiding the interpretation of negative results or statistically significant results where effects are small in clinical terms. The method is also useful for establishing the similarity of treatment groups at baseline or for showing that the effect of a potentially confounding variable is tolerably small. Finally, equivalence testing is recommended as a method for documenting the equivalence of biofeedback therapy to proven conventional medical therapies in clinical equivalence trials. Examples, drawn from published literature, are provided.

Biofeedback, Psychology↗

PubMed1995

Cutaneous vascular and sudomotor responses to isometric exercise in humans.

To identify whether isometric handgrip exercise (IHG) affects cutaneous vasoconstrictor and/or active vasodilator activities, seven subjects (6 men and 1 woman) performed 30% maximal voluntary contraction of a forearm under normothermic (1 bout) and hyperthermic (2 bouts) conditions. Skin blood flow was indexed by laser-Doppler flowmetry at a contralateral forearm site at which adrenergic vasoconstrictor function was blocked by iontophoresis of bretylium tosylate (BT) and therefore only has active vasodilation as a mechanism for reflex control. Skin blood flow was also monitored at an adjacent untreated site. Cutaneous vascular conductance (CVC) was calculated from the flow signal and noninvasive blood pressure. CVC was normalized to the value obtained from maximal vasodilation at that site. Sweat rate (SR) was measured at the same locations. During normothermia, IHG did not affect CVC at the control or BT-treated sites, nor did IHG affect SR (P > 0.05). The second bout of IHG in hyperthermia evoked significant reductions in CVC at the untreated (69.4 +/- 3.4 to 58.9 +/- 2.5% of maximum, P < 0.05) and BT-treated sites (75.4 +/- 6.1 to 64.4 +/- 6.2% of maximum, P < 0.05), whereas SR significantly increased (0.62 +/- 0.16 to 0.70 +/- 0.17 mg.cm-2.min-1, P < 0.05). These findings uniquely show that, in hyperthermia, IHG reduces active vasodilator activity while at the same time sudomotor activity is increasing. This suggests independent control of these effectors.

Adult↗

PubMed1993

Classical conditioning in children with attention deficit hyperactivity disorder (ADHD) and anxiety disorders: a test of Quay's model.

Quay (1988) put forward a model of childhood mental disorders based on Gray's (1982) theory that there exists within the brain a behavioral inhibition system (BIS), which processes signals related to aversive or punishing stimuli. According to this model, children with attention deficit hyperactivity disorder (ADHD) show lower than optimal levels of activity in this system, which leads to less responsiveness at a physiological level to signals related to punishment. Children with ADHD and controls were compared on a classical conditioning paradigm. Skin conductance and cardiac responses were measured in response to a conditioned stimulus that had been paired with an aversive unconditioned stimulus. There were no differences between the groups, suggesting that, in terms of classical conditioning, ADHD children are equally responsive to signals related to punishment as controls.

Anxiety Disorders↗

PubMed1993

The effects of severe bruxism on sleep architecture: a preliminary report.

Analysis of sleep in 5 severe bruxists revealed consistent sleep abnormalities. These abnormalities consisted of decreased REM latency (90%), decreased percentage of REM sleep (85%), and increased number of sleep stage transitions (75%). This sleep pattern suggests that bruxing can have a deleterious effect on sleep in otherwise healthy individuals. This effect on sleep can in the long run lead to difficulty in daytime functioning similar to the effects of sleep apnea or nocturnal myoclonus. These data also reveal a significant first night effect, hence future attempts at replicating and expanding these findings should take that into consideration. The small number of subjects studied, the lack of a standardized assessment of their daytime functioning, the lack of information regarding the degree of teethware and daytime bruxing activity limit the generalizability of our findings. A controlled study with a larger sample size can help further delineate the nature of such sleep changes as well as their impact on the patient's overall functioning.

Adult↗

PubMed1992

Electromyographic and affective responses of episodic tension-type headache patients and headache-free controls during stressful task performance.

Thirty-four subjects meeting diagnostic criteria for episodic tension-type headache and 42 who rarely experienced headaches participated in two laboratory sessions in which cephalic electromyographic (EMG) activity, electrodermal activity, heart rate, and finger temperature were recorded. Subjects performed relaxation, choice reaction time, psychomotor tracking, voluntary muscle contraction, and cold pressor tasks. Headache subjects showed significantly greater EMG activity than controls during baseline and stressful task performance. During relaxation, both groups reduced EMG activity from baseline levels, and there was no significant difference in EMG level between the groups during relaxation. Headache subjects reported higher levels of subjective anxiety, depression, anger, and stress than controls. Headache subjects also reported higher levels of pain than controls, and headache subjects reported greater pain during stressful task performance relative to baseline and recovery periods.

Adult↗

PubMed1992

The application of generalizability theory to surface electromyographic measurements during psychophysiological stress testing: how many measurements are needed?

Generalizability theory is an extension of classical reliability theory that allows multiple sources of measurement error in an experimental design to be investigated simultaneously. In the present study, generalizability theory was used to evaluate measurement error in psychophysiological test procedures used to differentiate tension headache patients from normal controls based upon measures of electromyographic (EMG) responding. Thirty-three subjects who met diagnostic criteria for tension-type headache and 40 normal control subjects who rarely or never experienced headache participated in two laboratory sessions. EMG activity of head and neck muscles was recorded while subjects performed baseline, relaxation, choice reaction time, psychomotor tracking, and cold pressor tasks. Variance components were computed for an experimental design having subjects nested within experimenters and crossed with sessions and replications. Generalizability coefficients were computed for combinations of various numbers of sessions and replications. The generalizability of EMG measures was highly variable, depending on the experimental conditions in force. The largest sources of measurement error were attributed to the unique responsiveness of individual subjects under a particular set of treatment conditions. For some stress tests currently in use, data from several testing sessions may need to be averaged in order to achieve acceptable levels of generalizability. Generalizability greater than 0.80 can be expected only rarely when data are collected during a single session. In the research setting, low generalizability may account for the failure of EMG-based stress tests to differentiate tension headache patients from controls during stressful task performance. In the clinical setting, the generalizability of information derived from "stress profiling" or muscle "scanning" techniques, which depend on results obtained during a single testing session, is doubtful.

Adult↗

PubMed1992

Cardiac sympathetic and parasympathetic activity during self-regulation of heart period.

Fourteen subjects attempted to increase and 15 attempted to decrease cardiac interbeat interval (IBI) while being provided with biofeedback of IBI, T-wave vector magnitude (TWVM), or respiratory sinus arrhythmia (RSA). Subjects in both groups showed directional change in IBI relative to a tracking control task, but the three types of feedback did not differentially affect performance. Voluntary IBI increases were associated with significant increases in TWVM and RSA, and voluntary IBI decreases were associated with significant reductions in RSA and nonsignificant reductions in TWVM. This pattern of results suggests that alterations in cardiac vagal tone are involved in voluntary IBI increase and decrease tasks. The results also suggest a role for cardiac sympathetic nervous activity in voluntary IBI increase. The role of changing respiration cycle period was also investigated.

Adolescent↗

PubMed1992

The effect of influential outliers on parameter estimation in regression analysis.

A comment is made on an article recently published in this journal by Borgeat, Elie, and Castonguay (1991). It is noted that the raw data contained an outlier which is shown to have had a large influence on their estimation of the regression coefficient. Analysis of the data using a nonparametric statistic that is optimal for long-tailed distributions showed that the true regression coefficient is probably smaller than that reported. Other approaches to the analysis of data containing influential outliers are discussed.

Biofeedback, Psychology↗

PubMed1991

Changes in the T-wave vector loop of the three-dimensional vectorcardiogram during exposure to cold pressor stress.

Three-dimensional vectorcardiography was used to characterize changes in the T-wave vector loop during exposure to cold pressor stress. Data were collected from 8 subjects during baseline, cold pressor, and recovery periods. Maximum vector length, polar angle of the longest vector, azimuth angle of the longest vector, sum of all vectors, polar angle of the vector sum, azimuth angle of the vector sum, surface area of the loop, and maximum distance between adjacent vectors were computed from the T-wave vector loop. The amplitude of the one-dimensional T-wave (TWA) was also computed. Interbeat interval and TWA decreased during hand immersion and increased during recovery. Of the vectorcardiographic measures, only maximum vector length and vector sum showed statistically significant change; both decreased during the task and returned to baseline during recovery. TWA accounted for 46% of the task related variance compared to 53% and 47% respectively, for vector sum and maximum vector length. Changes in TWA probably reflect a true change in cardiac electrical potential rather than a change in T-wave vector loop shape or orientation.

Adult↗

PubMed1991

A technique for the long-term application of surface electrodes.

A technique is reported for the long-term application of surface electrodes for ambulatory electromyographic (EMG) recording. Prior to electrode application the surrounding skin is lightly painted with tincture of benzoin. This treatment improves adherence to the skin of disposable electrodes and electrode attachment collars, reduces skin trauma associated with electrode removal, and minimizes sensitivity to electrode adhesives.

Electrodes↗

PubMed1991

Psychophysiological and endocrine responses to sexual arousal in women.

The unexplored possibility that a sexually induced endocrine response might prime further sexual arousal in women guided the current investigation. Healthy, premenopausal, heterosexual women in the follicular phase of their menstrual cycle were randomly assigned to either an experimental or a control group. The experimental group was exposed to a sexually explicit videotape, while the control group saw a nonerotic videotape. Ninety minutes later both groups saw a sexually explicit videotape. Vaginal vasocongestion and hormones (cortisol, prolactin, luteinizing hormone, testosterone) were measured continuously and subjective responses were sampled at 20-min intervals. Compared to controls, experimental subjects showed a greater amplitude and longer duration vaginal response to the second videotape. Subjective measures showed greater sexual response to the second erotic videotape compared to the first, an effect that was not mediated by the hormones measured here. Prolactin decreased significantly across the session for both groups, and several behavioral and affective responses were significantly correlated with hormonal levels. Commonalities and divergence with results of prior research point to the complexity and subtlety of endocrine interactions with sexual response as well as likely sex differences in hormone-behavioral interactions.

Adult↗

PubMed1991

Anger and hostility in tension-type headache.

A battery of standardized psychometric tests was administered to a group of 47 episodic tension-type headache sufferers and 47 headache-free controls. Compared to controls, headache subjects showed higher levels of anxiety, depression, and anger/hostility. The groups did not differ significantly on a measure of anger expressed toward persons or objects, but headache subjects showed significantly greater levels of suppressed anger. The results provide objective data that are in general agreement with predictions derived from psychosomatic theories about the interrelationships among anxiety,

Adult↗

PubMed1990

Dichloroacetate increases glucose use and decreases lactate in developing rat brain.

Dichloroacetate (DCA) activates pyruvate dehydrogenase (PDH) by inhibiting PDH kinase. Neutralized DCA (100 mg/kg) or saline was intravenously administered to 20 to 25-day-old rats (50-75g). Fifteen minutes later a mixture of [6-14C]glucose and [3H]fluorodeoxyglucose (FDG) was administered intravenously and the animals were sacrificed by microwave irradiation (2450 MHz, 8.0 kW, 0.6-0.8 sec) after 2 or 5 min. Brain regional rates of glucose use and metabolite levels were determined. DCA-treated rats had increased rates of glucose use in all regions studied (cortex, thalamus, striatum, and brain stem), with an average increase of 41%. Lactate levels were lower in all regions, by an average of 35%. There were no significant changes in levels of ATP, creatine phosphate, or glycogen in any brain region. Blood levels of lactate did not differ significantly between the DCA- and the saline-treated groups. Blood glucose levels were higher in the DCA group. In rats sacrificed by freeze-blowing, DCA treatment caused lower brain levels of both lactate and pyruvate. These results cannot be explained by any systemic effect of DCA. Rather, it appears that in the immature rat, DCA treatment results in activation of brain PDH, increased metabolism of brain pyruvate and lactate, and a resulting increase in brain glycolytic rate.

Animals↗